Practical Handbook for Wetland Identification and Delineation, Second Edition (Mapping Science)

PR ACTICAL HANDBOOK FOR

WETLAND IDENTIFICATION AND DELINEATION SECOND EDITION JOHN GRIMSON LYON • LYNN KRISE LYON

Boca Raton London New York

CRC Press is an imprint of the Taylor & Francis Group, an informa business

CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2011 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Version Date: 2011914 International Standard Book Number-13: 978-1-4398-3892-1 (eBook - PDF) This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers. For permission to photocopy or use material electronically from this work, please access www.copyright.com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com

Contents Preface......................................................................................................................vii Chapter 1 Introduction...........................................................................................1 Chapter 2 Background...........................................................................................9 What Is a Wetland?...............................................................................9 The Federal Definition and Criteria for Identification of Wetlands...... 14 Hydric Soils.................................................................................... 14 Wetland Hydrology Characteristics and Indicators........................ 17 Presence of Wetland Plants............................................................ 19 Chapter 3 Methods...............................................................................................25 Selecting a Method of Analysis and Level of Detail.......................... 25 Routine‑Level Methods and Analysis Procedures.............................. 26 Comprehensive Intermediate‑Level Methods and Analyses Procedures........................................................................................... 34 Comprehensive Advanced-Level Procedures...................................... 43 Chapter 4 Additional Background and Details.................................................... 45 Soils..................................................................................................... 45 Soil Surveys......................................................................................... 52 Munsell Color Charts.......................................................................... 53 Plant Measurements............................................................................54 Chapter 5 Additional Methods and Considerations............................................. 59 Topographic Maps............................................................................... 59 Aerial Photos and Remote Sensor Image Data................................... 65 Aerial Photos or Images for Characterizing Soils..............................80 Large Area Wetland Evaluations........................................................ 81 National Wetland Inventory Products.................................................84 Surveying and Mapping...................................................................... 85 Chapter 6 Advanced Methods, Hydrology, Soils, and Plants.............................. 89 Qualitative Methods............................................................................ 89 Regional and Local Guidance........................................................ 89 Hydrology....................................................................................... 91 iii

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Contents

Quantitative Methods.......................................................................... 91 Hydrology Measures....................................................................... 93 Wetland Hydrology Assessments................................................... 95 Hydrology Details..........................................................................97 WETS Tables................................................................................ 100 National Integrated Drought Information System and Drought..... 101 Hydrologic Indicators................................................................... 101 Hydrology and Water Techniques................................................ 102 Wetland Soils..................................................................................... 103 Soil Saturation.............................................................................. 103 Hydric Soils Lists......................................................................... 105 Soil Surveys and Soil Maps............................................................... 106 Growing Season................................................................................ 106 Calibrating Hydric Soil Field Indicators to Long‑Term Wetland Hydrology.......................................................................................... 107 Plants and Soil Chemistry................................................................. 108 Plants............................................................................................ 109 Visual Estimates of Plants............................................................ 110 Specimens..................................................................................... 111 Chapter 7 Advanced Methods, Mapping Sciences............................................ 113 Mapping Sciences.............................................................................. 113 Remote Sensing and Geographic Information Systems.................... 113 Geographic Information Systems................................................. 114 Format and Databases.................................................................. 115 Maps.................................................................................................. 117 Digital Elevation Models................................................................... 118 Digital Terrain Models, Digital Line Graphs, and Other Data......... 119 Surveying.......................................................................................... 119 Photogrammetry................................................................................ 120 Topographic Information.................................................................. 123 Floodplain Mapping.......................................................................... 124 National Wetlands Inventory............................................................. 125 Detailed Mapping and GIS............................................................... 127 Web Services..................................................................................... 128 Remote Sensing and Mapping of Wetlands...................................... 130 Remote Sensing............................................................................ 130 Photographs and Images............................................................... 132 Parts of the Spectrum and Radiation Characteristics.................. 135 Visible, Infrared, and Thermal Infrared...................................... 135 Radiation...................................................................................... 136 General Wetlands.............................................................................. 139 Spectral Analyses.............................................................................. 139 Detailed Remote Sensor Analyses.................................................... 141 Radar................................................................................................. 143

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Data Fusion........................................................................................ 145 Continental‑Scale Image Data Sets................................................... 145 Advanced Applications and Pattern Recognition............................. 147 Indicators........................................................................................... 148 Chapter 8 Oil and Wetlands............................................................................... 151 Oil Spills and Hazardous Waste........................................................ 151 Oiling and Methodologies................................................................. 152 Wetlands and Oil............................................................................... 152 Spectra............................................................................................... 153 Water Quality Issues and Oiling....................................................... 154 Oil Applications of GIS..................................................................... 155 Chapter 9 Permitting, Field Inspection, and Jurisdiction.................................. 157 The Permitting Process..................................................................... 157 Connectivity...................................................................................... 159 Jurisdiction........................................................................................ 161 Permitting and Environmental Attorneys......................................... 162 Wetlands and Riparian and Riverine Areas...................................... 162 Mitigation.......................................................................................... 163 The Report and Permitting................................................................ 165 Oversight........................................................................................... 165 Inspections......................................................................................... 166 Chapter 10 Conclusions....................................................................................... 169 Where We Are................................................................................... 169 Where We Are Going........................................................................ 169 Hydrology, Connectivity, and Jurisdiction........................................ 169 Definitions......................................................................................... 170 Advanced and Enhanced Methods.................................................... 170 Where Are We Going?...................................................................... 171 Appendix: Plant‑Related References.................................................................. 173 References.............................................................................................................. 175

Preface THE DELINEATOR’S MISSION The mission is simple. Draw a line in the sand or mud or dirt. The line is not arbi‑ trary but is created after collecting data from multiple sources, studying that data, and comparing it to standards (Figure P.1). Sometimes the standards are scientific. Sometimes they are legal. The delineator’s job is to decide what level of analysis is needed, collect data, and decide where the line should be drawn (Figure P.2). Wetlands are an important environmental resource. They are essential compo‑ nents in land drainage systems. They help improve water quality by acting as filters. They provide habitat for wildlife (Figure P.3). In general, wherever water meets land, there is an opportunity for a wetland. Wetland delineations are done for two main reasons. The first is scientific. Scientists study everything from water quality issues to habitat loss. Part of studying the resource is determining how big it is. A scientific delineation answers the ques‑ tion “Is it likely that this is a wetland?” The other reason for doing a wetland delineation is legal. The question in this situation is “Does this wetland meet the legal definition of a wetland?” Wetlands are a protected resource in the United States (Figure P.4). Various laws, statutes, and regulations govern their use (Figure P.5). Current government policy is that there will be “no net loss” of wetlands in the United States. Any proposed change in land use, features, or human encroachment is subject to review. The term jurisdictional wetland defines which lands are subject to this regulatory review. Like many laws, those governing jurisdictional wetlands have been subjected to legal tests (Figure P.6). Of particular note is the case of Rapanos v. United States and ultimately the Supreme Court decision. Rapanos allegedly drained and filled 22 acres of wetlands in preparation for a shopping mall he was planning to build. He claimed that the wetlands were “isolated” and thus did not meet the legal definition of a jurisdictional wetland. Part of the current definition of a jurisdictional wetland is that the wetlands must connect to the waters of the United States. The regulators and justice system applied a broader definition and sought millions of dollars in fines and penalties from Rapanos for filling a wetland. Rapanos took the issue to the Supreme Court. The Court, in a 4‑1‑4 plurality, held that isolated wetlands could not be con‑ sidered waters of the United States. Rapanos had not filled a jurisdictional wetland according to the Court. Since this ruling, “connectivity” has become a big issue. New laws have been pro‑ posed to change the jurisdictional definition to read “all waters of the United States.” For now, the definition of a jurisdictional wetland remains understood, but delinea‑ tors doing work need to be mindful of definitional changes (Figure P.7). Over seventeen years have passed since the first edition of this book. The basic methods and procedures for collecting wetland data are the same. What has changed vii

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Preface

FIGURE P.1  Pictured is an “ideal scene” that constitutes a wetland. Note the combination of standing water, hydric soils, and wetland‑loving plants.

FIGURE P.2  This combination of water, soils, and vegetation clearly meets the definition of a jurisdictional wetland.

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ix

FIGURE P.3  Even in arid regions there are wetlands. The wetland area and playa lake shown here are in a national park. Badwater, California, is known for being over 200 feet below sea level.

FIGURE P.4  Great Lakes coastal wetlands often have near‑shore beach barrier wetlands and adjacent wash‑over fans like those shown here.

dramatically is the availability of other types of data. Low and higher altitude aerial photographs or images, geographical information system (GIS) databases, updated and easily accessible land cover maps, and fine‑resolution satellite data are just a few of the resources available today. These can all be used to better characterize wetland conditions on a given property and to help decide where to draw the line around a wetland (Figure P.8). Though many references exist stating what mandatory technical criteria must be met, what field indicators to look for, and what other information may be useful, it is difficult to find actual directions on how to gather all the needed data. That is the purpose of this book.

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Preface

FIGURE P.5  Boreal forest ecosystems typically contain many classic examples of wetlands. Omitted from the image are the corollary heat, humidity, and bugs that accompany these places in the summer months.

FIGURE P.6  Note the contrast between desert hills surrounding the lower riverine areas and wetlands. It is always a challenge to determine whether these areas should be character‑ ized as arid or desert wetlands or as uplands and riverine systems.

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xi

FIGURE P.7  The spring season is a time of renewal in wetlands, though “green up” is often delayed compared to uplands. This is due to the slow warming of wetland waters and shading of tree and shrub structures as pictured here in central Ohio.

FIGURE P.8  Even in the winter season wetlands display their unique characteristics. Extensive knowledge of plant residue and hydric soil indicators is essential for characteriza‑ tion during winter seasons.

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Introduction

Identification and delineation of wetlands have become and remain an important topic. This is partly due to the variety of groups that have interest in wetlands, due to the value of the resources and the pervasiveness of the issue. Though the viewpoints of each group may be quite different on the valid uses of these areas, each shares a concern for wetlands and requires information to advance their agenda with regard to the resource. Knowledge of wetland identification and delineation is vital to the interests of all. The prevailing condition in the United States is that wetland laws are applied in new ways compared to historic efforts (Figures 1.1 and 1.2). The level of enforcement and varieties of wetland under scrutiny by governmental regulatory agencies and concerned parties have increased, and the advent of new state and federal laws pres‑ ents opportunities for additional oversight. No net loss of wetlands is the goal; the future will bring a different goal such as increasing wetland total area or increasing wetland value and function (Brinson 1993; Brinson et al. 1995; National Research Council [NRC] 1995; 2001). In this time of concern related to wetlands, many groups have compelling reasons to identify and delineate wetlands. The reasons important to an individual group, however, may be very different and as varied as the wetland related objectives of each group. Financial institutions frequently require wetland evaluations as part of an environmental assessment. This evaluation and the resulting “environment report” are necessary for granting of loans for development of property. Civil engineers need delineations of wetlands so that they can design the property site plan and excavations and filling of land mass. It is necessary to do so without disturbing the resource, for all know that wetlands provide important hydrological and other functions (Natural Resource Conservation Service [NRCS] 1997; Mitsch and Gosselink 2007). It can also be an expensive effort to work around a wetland resource and hence optimization of site plans is an economic and environmental necessity (Salvesen 1990; Hammer 1992). Conservation, recreation, and environmentally oriented groups may wish to iden‑ tify especially valuable wetlands for purchase as preserves or parks (Hruby et al. 1995). They also need to make wetland evaluations and possess knowledge to inter‑ pret the wetland reports of others. With such capabilities they can provide a learned dialogue on development and management related issues. Local and state governments need wetland evaluations for management and planning of existing properties or evaluations of properties for future acquisitions. Governments also need wetland analyses when they expand roads, utilities, and execute other governmental functions. As with the case of any owner of property, governmental agencies can only act with knowledge of the wetland resources that will be impacted (Figure 1.3). 1

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Practical Handbook for Wetland Identification and Delineation

FIGURE 1.1  High‑altitude or alpine areas hold wetlands that are pleasant to the eye and important habitat to wildlife and plants. Southern Utah near the North Rim of the Grand Canyon holds these resources.

FIGURE 1.2  Arid areas can hold a variety of plants and wetlands where water is relatively abundant. Hot springs and other sources nourish wetlands in the low‑altitude golf course at Furnace Creek, California.

Introduction

3

FIGURE 1.3  Great Plains areas, despite heavy farming, hold a variety of wetlands. Here, a copse of woods springs forth from rolling plains in eastern South Dakota.

This knowledge of wetland resources locally or regionally can also help with site planning that incorporates wetland resources into storm water retention, wet‑ land water treatment, and other activities that enhance a site (Tiner 1999). This also provides for a “green” approach to public stewardship and generally lowers relative costs of operation over time. The above examples are all valid reasons for interest in wetlands and reasons for having knowledge of methods for identifying their presence and mapping their loca‑ tions. The motivations of each group or interest are different, yet each needs to have knowledge of wetland resources to advance their respective agendas. The federal government’s interest in wetlands stems from a number of existing laws (W. Ward 1992) and the fact that they are a large land steward. The application of these mandates has received a higher level of attention in the last two decades; previous decades focused on wetland conversion, drainage, pest eradication, and general management that resulted in loss of land mass and/or wetland functions. An Executive Order further implemented by President George H. W. Bush expanded the scope of wetland activities from a historical path of drainage and filling to permit‑ ting activities with the goal of no net loss of wetlands. This Order resulted in an increase in oversight by the U.S. Army Corps of Engineers (USACE) under historic laws includ‑ ing Section 404 of the Clean Water Act (CWA, 33 U.S.C. 1344) and Section 10 of the Rivers and Harbors Act of 1899 (33 U.S.C. 403). Section 404 of the Clean Water Act also regulates discharge of sediment laden waters and materials into wetlands, and it has also received attention under the leadership of state water quality agencies and/or the U.S. Environmental Protection Agency (USEPA) under Section 401 (33 U.S.C. 1341). The advent of the Food Security Act of 1985 and the Farm Laws of 1990 and 2008 have also focused attention on wetland resources found on farmed lands. These have been the site of wetlands and wetland conversion to other land uses or land cover types such as production farming, silvaculture, and development (Carter 1990; Field et al. 1990; Dahl 2006).

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Practical Handbook for Wetland Identification and Delineation

As the primary federal agency concerned with wetland regulation, the U.S. Army Corps of Engineers (USACE) has moved vigorously over time to administrate their mandates. They have also moved to supply information to help in the process (for example, Guidice and Ratti 1995; Cole et al. 1997; Dunne et al. 1998; Hayes et al. 2000; Hauer et al. 2002) and made in‑roads into filling the void of information on local wetland evaluation information needs related to methodological options (for example, USACE 2006a–b, 2007, 2008a–e, 2009a–b, 2010a–f, and others). Increased regulation has led to concerns on the part of the public, and this level of action has contributed greatly to the dialogue on the wetlands issue. The U.S. Environmental Protection Agency has an oversight function, as well as this and other jurisdiction on issues related to water quality. Farmed wetlands are in the domain of the Farm Services Agency and the Natural Resources Conservation Service of the U.S. Department of Agriculture (USDA) and are candidates for reserve programs or easements to enhance their numbers and value. The attention of USACE to the regulatory element of the wetland issue has resulted in enforcement actions that were initially unanticipated by developers, engineers, and contractors. Initially, in the 1990s, project delay and work interruption was a real issue that influenced a great deal of people and projects. Subsequent wetland regulation, rules and laws have been interpreted in the courts and later by regulatory agencies. Hence, the issues have been and are still today a real, potential problem for landowners who are ignorant or not respectful of prevailing permitting issues includ‑ ing wetlands or have a complex site or site plan to address. On the other hand, there is a widespread perception that large quantities of wet‑ lands of smaller size are still being filled (Tiner 2003a; Tiner 2005). This is thought to occur despite the current level of enforcement by the USACE and the renewed awareness of wetlands‑related sanctions available to the public through government regulators. It is very difficult to gather statistics on trends, and this leads to further questions as to status. In this period of controversy related to implementation of process and procedures and interpretations by the courts, there has been limited information on how to proceed. A body of literature has been developed on the issues and how to provide an assessment of wetlands suitable for permitting activities of USACE. In the absence of detailed govern‑ mental information on local jurisdictional wetlands, it has become necessary for individ‑ uals to obtain wetland assessments before development of their property (Figure 1.4). This level of federal oversight has pointed to the lack of general knowledge related to regulatory requirements and lack of methods that are documented in the popular literature and particularly for difficult‑to‑identify wetlands (Figure  1.5). The past years have seen a great deal of work to clarify regional and local issues and that is continuing (Figure 1.6). The goal of this book and the previous edition is to present the characteristics and indicators of wetlands that are the focus of the jurisdictional wetland issue and present strategies and methods for making wetland identifications and delinea‑ tions to meet federal requirements (Figure 1.7). It has also been a goal to explain these complex issues in such a fashion that readers from a variety of backgrounds can better understand the issues and methods to identify and delineate a wetland (Figure 1.8).

Introduction

5

FIGURE 1.4  Building on and near wetlands is commonplace in many areas. Wetlands are juxtaposed with human settlements along the coastal wetlands of Galveston Island, Texas.

FIGURE 1.5  The desert wetland can be a subtle thing. In the middle ground, the dark tone is made up of bulrush plants filling a low spot that drains the surrounding countryside.

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Practical Handbook for Wetland Identification and Delineation

FIGURE 1.6  Wetlands were once known as the “devil’s land” and subjected to a variety of human activities. This area was formerly a quarry that supplied aggregate in the past. It is now prime wildlife habitat. Seen here is a blue heron looking for mice.

FIGURE 1.7  Distant light‑toned areas are playa lakes. They are sinks for surrounding run‑ off. Accumulated water supports wetlands. In relatively dry times, fine particles are shaped by winds into dunes and salt deposits here in the Great Basin Desert of Oregon.

Introduction

7

FIGURE 1.8  Streams meander downhill, incising the landscapes, creating riverine habitat and often wetlands. Pictured here are reclaimed surface mine lands near Zanesville, Ohio.

2

Background

WHAT IS A WETLAND? A wetland can be many things to many people. Generally, the word wetland conjures an image of a lake or pond surrounded by cattails that is alive with ducks, fish, frogs, and the like paddling about (Figure 2.1). Many types of wetlands depart from this model and they are often overlooked by people (Figure 2.2). Also, areas that have been historically wetlands in nature and have undergone conversion often revert back to their wetland characteristics and function if not man‑ aged over time. This is because the same hydrologic parameters of the landscape that occasioned the wetland are still present and active or can create wetland function again. These are often the same areas that are the subject of regulatory attention. Should the use of the area be proposed to change from the natural state or converted state such as farmlands to another land use or land cover such as commercial or residential land uses, the question of whether the area is a jurisdictional wetland can be posed. There is a need to recognize a variety of wetlands to insure optimal preservation and management and to comply with federal and state requirements. To appreciate the variety of wetland types, it is necessary to understand the ecological and environ‑ mental conditions that foster wetlands and learn the characteristics and indicators of wetlands as they exist in a natural state across the landscape (Tiner et al. 2002; Lyon 2001). Wetlands may be hard to distinguish from adjacent terrestrial or aquatic areas. This begs the questions: What is a wetland and what are the characteristics of wet‑ lands? There are a variety of definitions, just as there are a variety of people with ideas of “model” wetland types. A wetland can be described as a mix of characteristics from terrestrial or upland areas and the characteristics of aquatic or water environments. In essence, a wetland is the edge or interphase between uplands and adjacent water areas. The water may be in the form of rivers, streams, creeks, lakes, ocean areas, or wet spots. As such, wetlands may be found almost anywhere. They will possess characteristics of both upland and aquatic environments and exhibit a mix of soil, plant, and hydrological conditions (Figure 2.3). This mix of characteristics creates a unique habitat for life and Earth processes, but the mix also makes wetlands hard to identify. This is due to the inherent grada‑ tion of these characteristics from uplands to the aquatic environment and the pres‑ ence of both kinds of conditions in various combinations along that gradient.

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Practical Handbook for Wetland Identification and Delineation

FIGURE 2.1  Weeping willows and other wetland and facultative wetland plants can sur‑ vive, thrive, and procreate in the presence of rising and ponding waters.

FIGURE 2.2  Riverine and wetland areas are often adjacent in stream courses. To separate them out, it is necessary to carefully evaluate soils looking for hydric conditions and then to closely examine and evaluate plants. This is tricky because the stream course, though river‑ ine, is made of many wetland‑like areas.

Background

11

FIGURE 2.3  The plains hold many wetland or wetland‑looking areas. Cottonwood trees and a stream meander are caught in the winter season. See the white snow defining the water path.

There are a variety of formal wetland definitions. Several have been used by vari‑ ous groups, including federal agencies. Four federal agencies have collaborated over a number of years to arrive at an “accepted” definition for use in their activities. The definition comes from the “Corps of Engineers Wetlands Delineation Manual.” Here, it is referred to as the “Wetlands Delineation Manual” (U.S. Army Corps of Engineers [USACE] 1987). The definition stems from the Clean Water Act and from USACE regulations and work over a number of years with other groups. The definition describes a wetland as: Those areas that are inundated or saturated by surface or groundwater at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands generally include swamps, marshes, bogs, and similar areas. (See also EPA, 40 CFR 230.3, definitions, and 230.41, Section 404(b)(1) Guidelines for Specification of Disposal Sites for Dredged or Fill Material; and CE, 33 CFR 328.3, Navigation and Navigable Waters)

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Practical Handbook for Wetland Identification and Delineation

FIGURE 2.4  Floating leaf plants become apparent during flooding buoyed by sedi‑ ment‑filled waters.

This definition is used by the USACE and U.S. Environmental Protection Agency (USEPA) and other agencies and by people using the Wetlands Delineation Manual (USACE 1987) for their work. In essence, it is also an operational definition. From it stems the three criteria used as the standards to be applied in identifying jurisdic‑ tional wetlands (Figure 2.4). The waters addressed in the application of this definition include those impor‑ tant to USACE. Under Section 404 of the Clean Water Act (CWA), this definition may be applied to regulate discharges of dredge or fill material in the waters of the United States. These areas may include navigable waterways, most lakes, riv‑ ers, streams, impoundments, wetlands, sloughs, prairie potholes, wet meadows, ponds, and the like (USACE 1987; Maltby and Barker 2009). In essence, this definition and the application of it to waters under USACE juris‑ diction result in most wetland areas falling into the domain of regulatory oversight. Other wetlands found above the headwaters but with connectivity (as per current interpretations) and found to have indicators of all three wetland criteria may also be subject to the regulatory attention of USACE when discharge or filling is to occur and under prevailing interpretations. There are several other definitions of wetlands that may be important. This is particularly true of wetland areas that may be farmed lands or areas where state or

Background

13

other laws based on other definitions also prevail (for example, for inland wetlands in Michigan or New Jersey). There are also historical definitions that have been impor‑ tant (Shaw and Fredine 1956) to the interpretation of wetlands and the development of definitions over time (Cowardin et al. 1979). The use of a given definition depends on the characteristics of the study area and interests of the particular agencies or groups that may be involved in wetland evaluations. Another important alternative definition is found in the Food Security Act of 1985, which codified wetlands and farming activities. This is because it is applied to farmed lands, which are treated differently from unfarmed wetland areas. This approach has been reiterated in later legislation such as the Farm Act of 2008. Wetlands are defined as areas that have a predominance of hydric soils and that are inundated or saturated by surface or ground water at frequency and duration sufficient to support, and under normal circumstances do support, a prevalence of hydrophytic vegetation typically adapted for life in saturated soil conditions, except lands in Alaska identified as having a high potential for agricultural development and a predominance of permafrost soils. (U.S. Department of Agriculture [USDA] 1988)

Later Farm Bills have further refined the activities that involve wetlands for farm‑ ing (Farm Act of 2008). Over the years, the U.S. Fish and Wildlife Service have used a definition of wet‑ lands from the National Wetlands Inventory (NWI) Program (Figure 2.5). The defi‑ nition states: Wetlands are lands transitional between terrestrial and aquatic systems where the water table is usually at or near the surface or the land is covered by shallow water. For purposes of this classification wetlands must have one or more of the following three attributes: (1) at least periodically, the land supports predominantly

FIGURE 2.5  This stream meander is laden with salt deposits. We can see that a river‑ ine system is apparent, but is there a wetland present? An assessment will characterize the conditions.

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Practical Handbook for Wetland Identification and Delineation hydrophytes, (2) the substrate is predominantly undrained hydric soil, and (3) the substrate is non‑soil and is saturated with water or covered by shallow water at some time during the growing season of each year. (Cowardin et al. 1979)

THE FEDERAL DEFINITION AND CRITERIA FOR IDENTIFICATION OF WETLANDS The finding of a jurisdictional wetland is based on criteria set forth in the Wetlands Delineation Manual (USACE 1987). An area is considered a jurisdictional wetland only if all three wetland criteria are met. Evaluation of these three wetland criteria includes a determination as to (a) whether the soils are considered hydric or waterlogged, (b) whether the soils show demonstrable evidence of hydrologic conditions associated with flooding or ponding of water, and (c) whether 50% of the dominant plants found growing on the site are those commonly found in wetlands. Fundamentally, property areas that fail to satisfy one of the three wetland crite‑ ria are not considered jurisdictional wetlands. The exact conditions depend on the Delineation Manual that prevails at a given moment, and one should be aware of current conditions based on the manual and any prevailing regulatory guidance from the USACE (2010a–f). It is also very desirable to document conditions in a wetland report based on study of the site, as one would develop an environment report for any parcel of land. The exceptions to the requirement that three criteria be satisfied are properties that have been disturbed. These areas may not exhibit one or more of the criteria, due to burial or removal, and represent a special case. These areas are evaluated using less than the total three criteria. The procedures are similar to a regular evaluation, except that the wetland elements that are disturbed or missing are no longer a factor in the analyses. This procedure is described in the Wetlands Delineation Manual with updates (USACE 1987) and other places (Federal Interagency Committee for Wetlands Delineation [FICWD] 1989; USEPA 1991, 2008; USACE 2009a–b). It is desirable, here, to address the three criteria characteristics in detail. This approach allows for appreciation of phenomena that cause an area to exhibit wetland conditions. It also demonstrates how information on hydric soils, wetland hydrol‑ ogy, and wetland plants helps to define a jurisdictional wetland area. It can also promote the understanding of indicators employed in an assessment of jurisdictional wetlands and help one appreciate the complex mix of the three characteristics that make a wetland.

Hydric Soils If a given soil is subject to flooding or ponding of water for more than two weeks during the growing year period (USACE 1987), it will often demonstrate hydric or waterlogged soil characteristics. These waterlogged conditions greatly influence soil chemistry and the conditions for plant life (Figure 2.6).

Background

15

FIGURE 2.6  The confluence of creeks yields year‑round moisture. Shrub wetland areas in the middle of the scene lead into a rush‑filled marsh.

The significance of standing water or waterlogged soils is that chemical and bio‑ logical oxygen demands will rapidly exhaust oxygen that is available in the soil. This is significant because a lack of soil oxygen for roots will commonly cause death of upland plants during the growing season. All plant roots need air to respire and use airborne oxygen to metabolize sugar and supply energy for life. Diffusion of oxygen into soil is a slow process in general. It is even slower in water. Migration of oxygen into waterlogged soils and into the root zone of plants is also very slow and proceeds at an unacceptable rate compared to the oxygen needs of upland plants and other biological and chemical oxygen demands in the soil. Hence, areas that experience periodic flooding or ponding of water are often pop‑ ulated by plants adapted to poor oxygen conditions in the root zone. These plants are commonly known as wetland plants (Figure 2.7). Soils that experience these oxygen‑poor or anaerobic conditions on a periodic basis are characterized as being hydric. The USDA’s National Technical Committee for Hydric Soils Criteria has developed a list of soils that often display hydric soil characteristics (e.g., http://soils.usda.gov/use/hydric/). One can identify potential hydric soils by examining a USDA county soil survey (USDA 1975; http://soils.usda.gov/survey/). Soil types found on the site of interest can

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Practical Handbook for Wetland Identification and Delineation

FIGURE 2.7  Note the ponded water in the foreground and the white peaked plant debris just above it in the photo. This is a winter scene in a disturbed area. Determining whether this is a wetland requires ample experience and possibly additional techniques.

be compared to those on the Hydric Soils List. The presence of hydric soils on a site is often interpreted administratively by federal agencies and other groups as being indicative of potential wetland soil conditions and potential jurisdictional wetlands. Evaluation of the county soil survey for soils on the USDA Hydric Soils List (USDA 1991 and revisions) is a necessary first step in an evaluation of a given prop‑ erty. If soils on the Hydric Soils List are found on the property, it will often be incumbent upon the landowner to determine whether jurisdictional wetlands are present by analysis of the site using the three criteria of the Wetlands Delineation Manual (USACE 1987) or other current wetland delineation methods required locally or regionally. In a practical sense, the presence of soils from the USDA Hydric Soils List on a given property indicates a potential jurisdictional wetland condition (USDA 1996). This means that the property may be subject to administrative review by USACE for the presence of jurisdictional wetlands, should the landowner propose to change the end‑use of the property. This is because the soil survey and Hydric Soils List are often used by federal agencies and others as a “first cut” evaluation of the potential for wetlands (Wakeley et al. 1996). Soil survey information and other sources such as NWI maps (http://www.fws. gov/wetlands/) may be interpreted by USACE personnel in judging the probability of finding jurisdictional wetlands on a given site (n.b., Web site addresses cited in the text were checked for service in late 2010). Hence, the person doing the delineation or the delineator should pay attention to those characteristics of a given site and take the condition into judgment. Soil surveys are available from the county offices of the Natural Resource Conservation Service (NRCS) of the USDA or from their Web sites (http://soils.usda. gov/survey/). These offices are commonly found in the county seat of government and the state capitol and can be identified in the governmental section of local and regional Web sites or through like directory services.

Background

17

FIGURE 2.8  The dark area shows where river wash has undermined the ground along the outside of the streambed curve. This is where water velocity is the highest and can do the most work in eroding the banks. Often the resulting deposits can become sediments for the foundation of wetlands.

The USDA Hydric Soils List can be obtained from the local NRCS office or from state headquarters of NRCS in each state capitol. It is also available from the USDA‑NRCS National Technical Committee for Hydric Soils, Criteria for Hydric Soils at http://soils. usda.gov/technical/manual/ or http://soils.usda.gov/technical/handbook/. Hydric soil indicators can be identified in the field. This generally involves obser‑ vations made by digging a hole or probing the soil to approximately 18 inches in depth. The soil color (Munsell Color 1990) is evaluated using hue, value, and chroma characteristics from the Munsell Color Chart for soils (Figure 2.8). Observations of the macroscopic manifestations of anaerobic soil chemistry should also be made and can be used in identifying waterlogged conditions.

Wetland Hydrology Characteristics and Indicators Soils and plants that are generally flooded or saturated to the soil surface display a number of characteristics that are diagnostic of waterlogging or anaerobic soil con‑ ditions (Figure 2.9). These characteristics or indicators include the presence of soil colors or mottling, dark soil color or chroma, as well as the presence of chemical constituents associated with chemical reactions that occur in the absence of oxygen. Other overt signs of the influence of water and conditions of wetland hydrology include flood “markings” on the soil surface and coatings of clay or silt particles that may appear on plants. Rafted debris may be present on the ground at the margin of flooding (Figure 2.10). Materials or debris may be found suspended in plant branches or stems several feet above the ground. During inspection of the hole dug in the soil, it is desirable to observe whether water seepage is encountered within 18 inches or so of the soil surface. This is a strong indicator of wetland hydrological conditions and an important jurisdictional measure of soil hydrology. An obvious filling of the hole with water is a very good

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Practical Handbook for Wetland Identification and Delineation

FIGURE 2.9  A lone cottonwood, water courses, woods, and wetlands are common scenes among prairie agriculture in rolling hills of glacial origin.

FIGURE 2.10  Winter scenes are the most challenging for delineators. Deposits of deterio‑ rating plant residue and the lack of trafficking in a farm field can be used to help identify the location of possible wetlands. In this case, a tree line follows a country path along a stream bed, making a good starting point for characterization activities.

indicator of a seasonal high water table. It can be readily interpreted as meeting the hydrological condition based on the manual (USACE 1987) and its criteria. Another method of determining potential wetland hydrological conditions is to evaluate the proximity of a given property to rivers, streams, gullies, and nearby wetlands of significance. This can be performed without a field visit and may be completed by using available maps or aerial photos or satellite images. Federal Emergency Management Agency (FEMA) flood plain maps are also useful for identifying adjacent riverine characteristics and may be obtained from FEMA. The

Background

19

question of connectivity is a good jurisdictional one, and such evaluations will be helpful in answering that question. All these characteristics can be important in the assessment of jurisdictional wetlands. These are all descriptive indicators. The Wetlands Delineation Manual (USACE 1987) specifically asks for these sorts of data and it is best to focus initial data collection efforts on the acquisition of the required information. Certainly more detailed measurements can be employed if available, if their use is valuable for better characterizing the conditions, or if a higher level of detail is requested by USACE.

Presence of Wetland Plants The third important criterion is whether the site has an abundance of plants adapted to grow in wetland or waterlogged soils. In general, plants are adapted to grow in specific environments and compete with each other for nutrients and light. One com‑ petitive advantage for a given plant species is the capability to grow and reproduce in the air- or oxygen‑free environment of waterlogged or anaerobic soils. Waterlogged soils present a very stressful environment for many plants. However, for the plant species that have capabilities to grow in this environment, it can provide a competitive advantage over other plants and provide quality habitat for the wetland plant. Wetland plants exploit this stressful environment to grow and reproduce and thereby “out‑compete” upland plants for a habitat or “home.” A number of plants are capable of growth and reproduction in wetlands. Plants exhibit structural or physiological adaptations to accommodate their growth in wet‑ land areas. These adaptations include plant biochemistry optimized for anaerobic soil conditions and the presence of plant tissue for conduction of air from above to the roots (Sculthorpe 1967; Good et al. 1978; Richardson and Vepraskas 2007), among others. Plants may also change their form of growth to maximize surface contact with the air environment through structures such as shallow roots, multiple tree trunks, or roots on the surface of the ground (Figure 2.11). Plants that have these characteristics are commonly found in wetland environments, and there is a wealth of scholarly references devoted to their study over time and in the literature (Sculthorpe 1967; Hutchinson 1975; Teskey and Hinckley 1978). The identity of plant species that can exist in wetlands is known and generally agreed upon within the scientific community (Reed 1988; USACE 2009a–b, 2010a–f). A list of plant species and their affinity for wetland conditions has been published and is referred to here as the “National List” or as Reed (1988), the National List of Plant Species That Occur in Wetlands: 1988 National Summary, published by the U.S. Fish and Wildlife Service (USFWS) of the Department of Interior and maintained by USACE. The National List is a fundamental resource for identifying the wetland affinity of individual plants species. This list is used in wetland delineation and related studies for jurisdictional purposes. It is important for all interested parties to obtain a paper or digital copy or have access to updated lists through the Web. Also, certain wetland delineation consulting groups publish their own adaptations of the National List for local or regional areas, and these may be useful and can be found by Web search.

20

Practical Handbook for Wetland Identification and Delineation

FIGURE 2.11  Roads and utility corridors where the land has been altered are often homes for wetlands. The Great Basin holds many such places that perform useful functions.

Revisions of the National List have been published since 1988 and will continue to be so in the future and can be found on the USACE Web site http://www wetland-plants. usace.army.mil/. The capability of a given plant to live in a wetland and the probability of it being found in a wetland is rated in one of five categories. This assessment has been made for thirteen different regions of the United States. The system of categories (Reed 1988; http://www.wetlands.com/fws/plants97. htm) recognizes that certain plants are found almost exclusively in upland environ‑ ments (system category: UPL or uplands). A number of plant species maybe found in wet environments less than 33% of the time and are termed facultative upland plants (category: FACU). Some species usually occur in wetlands with an estimated probability of 34–66% of the time but are occasionally found in non‑wetlands and are called facultative (FAC) wetland species. Some plants are usually found in wetlands with an estimated probability of 67–99% and are called facultative wetland plants (FACW; Figure  2.12). Certain plants almost always occur in wetlands with an estimated probability of >99% and are called obligate (OBL) wetland plants (Figure 2.13). Often times a suffix of “+” or “−” is applied to indicate that the plant is found on the higher or lower ends of the range in probabilities. In the process of wetland delineation, one must identify the plant species that are the most common or dominant plants in a given area. These common plants must be estimated as to their relative abundance (Figure 2.14). One simple method is to estimate dominance for each common plant species on an area basis or areal coverage extent basis in percentage. Such an evaluation is made for each domi‑ nant plant species in each layer of vegetation including the tree, shrub, vine and ground (herbaceous) layers. If a vine or other demonstrable layer or stratum of vegetation exists, it should be used in the analyses (Figure 2.15).

Background

21

FIGURE 2.12  Farmed wetlands and farm drainage go hand in hand. This winter scene shows a conservation tilled field and a distant copse of woods. Often the woods will be either wet or stony and have resisted land clearing and tillage for a century or more.

FIGURE 2.13  A forested scene with squishy land surrounding a pothole‑like area of water is likely a wetland. But is it a jurisdictional wetland? One should do the analysis and check for connectivity to waters.

It seems to be best to separate the vegetative cover into the common three lay‑ ers of tree, shrub, and ground. The assessment of vegetative dominance of wetland plants incorporates the sum dominance, and that is the deciding factor. The expert determines the status of wetlands in a given area by recording all domi‑ nant plants. The determination ivtself involves enumerating only the plants most capa‑ ble of existing in wetlands. These are the FAC, FACW, and OBL categories of plants. A given site is determined to be a wetland for this criterion when the total domi‑ nance of FAC, FACW, and OBL plants exceeds 50% of the total dominant plants found on the site.

22

Practical Handbook for Wetland Identification and Delineation

FIGURE 2.14  Desert areas, particularly in the high desert of the Great Basin, drain locally rather than running out to the sea. Here is a large lake reservoir. Note the cottonwoods along the shoreline and the Scirpus (bulrushes) emerging from the shallows in the foreground.

FIGURE 2.15  The Mojave Desert has a number of springs and wells that supply water for the area. Palms, salt cedar, and other shrubs form layers and mark these waters near Furnace Creek.

A variety of methods are recorded in the scientific literature for measurements of plants. There are a number of methods favored by the individuals (USACE 2009a–b, 2010a–f) and a number of methods that are workable and can be employed in analy‑ ses (Wakeley 2002). For delineations, it is necessary to estimate the dominance and relative abundance of dominant species, and it is necessary to do so using methods that are not overly time consuming (Figure 2.16). Determination of dominance may be completed by visual estimation or by more complex estimation procedures such as the point intercept method or some

Background

23

FIGURE 2.16  Despite the partial ice cover, this pond near Ann Arbor, Michigan, displays many of the characteristics of a wetland in the early spring. The woody plant residue from prior seasons is the most obvious.

quadrant‑based methods (Mueller‑Dombois and Ellenburg 1974; FICWD 1989; Lyon 1993). The method of choice is up to the person conducting the delineation, and the approach should be acceptable to USACE (for example, USACE 2010a–f). The method should be repeatable and should be uniform in its application. Results of these analyses can be recorded in the field. The field results can be summarized on record sheets such as those provided in the Regional Supplements to the Wetlands Delineation Manual (USACE 2009a–b, 2010a–f) or from other sources that have developed sheets and may be found through a Web search.

3

Methods

A number of methods can be used to delineate wetland areas. As per the Wetlands Delineation Manual (U.S. Army Corps of Engineers [USACE] 1987), one must identify potential jurisdictional wetlands by addressing the three criteria. This may be accomplished by using a combination of data sources and field indica‑ tors with different levels of attention (Figure 3.1). These levels may be applied based on the need for information and documentation as per the tractability of the issue. To identify and delineate wetlands in a given area it is best to use a combination of existing data, reference materials, and field evaluation procedures. This approach allows all three criteria to be addressed in detail and their conditions recorded for future validation. Field measurements may involve ground examinations of the three criteria (Figure 3.2). These activities may include field evaluations of hydric soils that may have been identified on soil survey maps or other sources of information; evaluations of indicators of waterlogged soils and/or flooding associated with wetland hydrol‑ ogy; and estimations of dominant plant species and the relative percentage of those plants that are commonly found in wetlands. The following activities have been found to be beneficial for identification of jurisdictional wetlands and for delineating and mapping wetlands.

SELECTING A METHOD OF ANALYSIS AND LEVEL OF DETAIL An important initial consideration in any project is the level of detail and efforts nec‑ essary to identify and delineate wetlands. The Federal Wetlands Delineation Manual (USACE 1987) presents three levels of effort that yield an increasing quantity of detail. Selection of the level of effort can be very helpful in tailoring the work product to the need for information. One can also start with the basic level and progress as results or the issues at hand demonstrate the need for more information (Figure 3.3). The routine level of evaluation involves office efforts and perhaps limited field‑ work for an initial or reconnaissance‑level effort. It is a very good starting point, because it reveals the possible extent of wetlands and identifies the potential for gen‑ eral wetland areas or potential jurisdictional wetlands. The intermediate‑level evaluation employs field‑based methods to evaluate wet‑ land resources and to quantify wetland characteristics and produce information to inform a detailed report (Figure 3.4). The results of this delineation and the inter‑ mediate‑level report present a good level of information and can be used in various permitting activities that involve the USACE. The resulting work can be used by the USACE and can also inform the oversight activities on permitting by the U.S. Environmental Protection Agency (USEPA). These activities all come under the 25

26

Practical Handbook for Wetland Identification and Delineation

FIGURE 3.1  In this farm field in the glaciated part of southeastern Ohio, frozen water and snow cover much of the land in early spring. Vegetation is crop residue. Delineations under these conditions require careful and thorough efforts.

auspices of sections of the Federal Water Pollution Control Act, commonly known as the Clean Water Act (CWA). Comprehensive‑level methods are highly detailed and laborious and may be required for special case wetland areas that are under intense scrutiny or for better characterization of wetlands for purposes of wetland function evaluations in support of mitigation (Figure 3.5) or for other needs as discussed in later chapters.

ROUTINE‑LEVEL METHODS AND ANALYSIS PROCEDURES The preliminary or “routine”‑level of analysis is a good place to start any effort. This is because one can conduct a “reconnaissance” and characterize the scope of the work. The routine evaluation indicates where potential jurisdictional wetlands or general wetlands may be located. It can involve an office evaluation of the soil survey and a field inspection for the presence of wetland plants, hydric soils, and wetland hydrology (Figure  3.6). Further detail can be collected within this framework by later applying comprehensive/intermediate‑level evaluations to determine whether local areas are truly jurisdictional wetlands. For the purposes of routine‑level analyses, there is a need to define the concept of a “potential jurisdictional wetland.” This label or category allows for documenting a

Methods

27

FIGURE 3.2  Identifying plants is difficult because wetlands have a combination of upland, wetland, and aquatic plants. These can be a greater challenge where wetlands and wetland plants are ephemeral or, as shown here, practically invisible during the off‑season. Delineators should try, whenever possible, to make plant and wetland determinations during the season when the indicators can be expected to be present.

potential condition before the evaluation of all three wetland criteria has been made. Usually, it is necessary to “scope” the potential jurisdictional wetlands. This scoping or routine‑level wetland report will allow the client to appreciate the conditions and choose whether to go forward (Lyon 1993). Hence, it is desirable to define a potential jurisdictional wetland as an area that exhibits one or more of the three wetland criteria. This potential jurisdictional wet‑ land may also be called a general wetland (Lyon 2001). Wetlands identified during routine‑level evaluations may be jurisdictional wet‑ lands but it is necessary to complete an intermediate‑level evaluation to make an actual determination as to whether the area is a jurisdictional wetland. The inter‑ mediate‑level wetland determination would involve greater field sampling detail on plants, soils, and hydrological conditions (Figure 3.7). To complete a routine investigation and identify potential jurisdictional wetlands, it is desirable to use the following suggested steps and procedures. One should conduct the routine‑level effort by:

28

Practical Handbook for Wetland Identification and Delineation

FIGURE 3.3  Delineators should look for the three layers in any vegetative community: trees, shrubs, and ground cover. This desert waterway displays only two of the four major layers. The ground and shrub layers are apparent but the tree and vine layers are absent. It also shows how one or two of these layers may be missing from certain parts of the area, yet one has to work with this. The location is the Death Valley National Park in California.

FIGURE 3.4  Isolated wetlands are difficult to discern from jurisdictional wetlands. Pictured is an isolated hardwood swamp found near a roadside rest stop in Union County in central Ohio.

Methods

29

FIGURE 3.5  Note the high water, plants, and hydrologic indicators of flotsam. The classic wetland indicators are present but separated in space because it is a sandy beach barrier. The location is the Straits of Mackinac of Lake Michigan, Lower Peninsula of Michigan. This is also nesting habitat for the endangered piping plover.



1. Obtaining the county soil survey. Examine the soil type boundaries. It may be useful to transfer the soil boundaries from soil survey maps onto a topographic map or geographic information system (GIS) map of the site. If an engineering‑style map is available this may also be used. This can be done for all soil types on the property, with particular attention to soils found on the USDA Hydric List (U.S. Department of Agriculture [USDA] 1991 or http://www.USDA.gov/hydricsoils). 2. Taking the soils map and other data sources such as aerial photos or images, National Wetlands Inventory (NWI) wetland maps, and large‑scale topo‑ graphic maps to the field and walking the site. Pay attention to lower eleva‑ tion areas, all streams, creeks, gullies, wet spots, and wetlands. Evaluate any anomalous conditions of soil, bedrock, or hydrology that could result in flooding, ponded water, or a high water table (Figure 3.8). Walk the entire site and visit the entire property. Walk or drive the sur‑ rounding area. Be alert to the above and other conditions. On the site, make notes as to the presence of indicators of hydric soils, wetland hydrology, and wetland plants.

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Practical Handbook for Wetland Identification and Delineation

FIGURE 3.6  Trees with fat bases are often a good indicator of wetland hydrology.

It is vital to evaluate the entire site and avoid omission of small or hidden wetlands. This is necessary to assure that all potential jurisdictional wetlands are identified and located. It is also important because the USACE will often wish to inspect the entire site, and omission of wetlands can create many diffi‑ culties as to whether the evaluation was performed in total (Figure 3.9). Also, because findings are administered based on the presence and area of wet‑ lands, omissions go to the heart of the quality and quantity of the evaluation. One should pay particular attention to hydric soil areas as mapped on the soil survey (http://soils.usda.gov/survey/, http://soils.usda.gov/use/hydric/). Also, look for wetland plants that may “signal” the presence of hydric soil conditions that do not appear on the soil survey or conditions such as hydric soil inclusions within the larger soil survey mapping unit. One should note the presence of wetland plants, in particular the obligate wetland plants and facultative wetland plants. 3. Taking the field information, available aerial photographs and images, the county soil survey, and other pertinent data and identifying potential wet‑ land areas (Figure 3.10). It is desirable to identify any area with one or more wetland indicators as a potential jurisdictional wetland or general wetland. These locations can be noted and visited or visited again. Upon further examination, they may be later sampled at the intermediate level of detail to determine whether true jurisdictional wetland conditions are present.

Methods

31

FIGURE 3.7  Indicators here are similar to Figure 3.6, yet the absence of standing water demonstrates the value of the indicator.

Map the boundaries of potential jurisdictional wetlands on an overlay of the property map, large‑scale topographical map, or engineering‑style map or GIS map. The desirable minimum mapping unit should be one tenth or one hundredth of an acre. Using a digitizer, a scanner, a planimeter, or another area measurement device, make a preliminary estimate of the total area of potential jurisdictional wetlands from the mapping product. 4. Integrating information from other data sources, such as watershed and drainage maps, to help characterize any additional resource conditions that may be potentially of jurisdictional interest. 5. Spending some time checking the routine-level wetland report. This may include further field visits. It is important to be sure that no potential juris‑ dictional wetlands have gone unnoticed (Figure  3.11). The landowner is depending on the expert for an accurate assessment of potential jurisdic‑ tional wetlands. Later, the landowners will conduct their efforts based on the report or use it to initiate an intermediate‑level evaluation and report. An inaccurate report at any level of detail can cause incredible difficulties after commencement of development, should a regulatory or other agency become involved and a conflict results as to the presence or absence of wet‑ lands on the site.

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Practical Handbook for Wetland Identification and Delineation

FIGURE 3.8  Flotsam is deposited high in these branches from the surrounding Earth. How did they get there? This indicates that water levels may have been much higher previously, even though those same conditions are not present during a field visit.

FIGURE 3.9  This is a classic scene of a swamp in the spring. Standing water, emerging plants, and other indicators leave little doubt that this is a wetland area.

Methods

33

FIGURE 3.10  In late spring, ponded water is characteristic of a farmed wetland. The water conditions will delay planting. Subtle topographic differences exist with the home in the background sitting on a higher elevation. This site is near Circleville, Ohio.

FIGURE 3.11  Drainage pipe and ditches abound in the suburban environment. These man‑made features alter the connectivity of water conveyances to reduce or eliminate flood‑ ing of structures.

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Practical Handbook for Wetland Identification and Delineation

Completion of these steps provides a certain minimum level of information and allows identification of areas that are potential jurisdictional wetlands. This prelimi‑ nary or routine‑level report is suitable for identifying the scope of the problem and is the starting point for further intermediate‑level analyses to characterize potential jurisdictional wetlands as jurisdictional wetlands or not (Figure 3.12).

COMPREHENSIVE INTERMEDIATE‑LEVEL METHODS AND ANALYSES PROCEDURES A higher level of detail is supplied by comprehensive intermediate‑level evaluation procedures (USACE 1987). The resulting product is valuable for making an actual determination of jurisdictional wetlands and their quantities. Such an analysis and the documents resulting from it can be used to respond to wetland‑related ques‑ tions posed by the USACE and the Clean Water Act (CWA), section 404, permitting process. To complete an intermediate‑level evaluation it is necessary to conduct a more intensive effort in the field and office, compared to the routine level of analysis. These steps are outlined in the Wetlands Delineation Manual (USACE 1987) and are provided here along with enhancements developed from many applications of

FIGURE 3.12  Farmed wetlands often maintain many of their wetland characteristics over time despite human intervention. Larger wetlands filter water through farmed areas in wet years, often preventing planting or killing germinated seeds.

Methods

35

FIGURE 3.13  Where water and land meet, wetland plants propagate, procreate, and flour‑ ish. Here is a desert wetland in South Africa.

these procedures by the authors and colleagues. It is assumed that a routine‑level evaluation has been conducted to characterize the scope of the problem and that potential jurisdictional wetlands need to be identified and delineated as jurisdic‑ tional wetlands or not (Figure 3.13). The steps in the evaluation may include the following:

*

1. Take data source materials developed from the routine‑level evalua‑ tion and go to the field. Begin sampling for the three criteria to char‑ acterize the potential jurisdictional wetlands at the locations of interest (Figure 3.14). Record information collected in a notebook with appropri‑ ate writing instruments for the field (e.g., permanent markers or pens and waterproof paper). For the intermediate‑level effort, it is desirable to locate the field sam‑ pling in some reference framework. This can be accomplished by the estab‑ lishment of a grid system of points to be sampled in the field. A 100 × 100 foot grid mesh has been found to be suitable size and resolution for sam‑ pling at the intermediate‑level of detail.* U.S. customary units are used here because most if not all land parcels are in the U.S. Land Survey System, which uses these units, and parcels of land are recorded and deeded in these units. Many map products are in U.S. customary units, and so forth. Hence, these units are used throughout the text.

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Practical Handbook for Wetland Identification and Delineation

FIGURE 3.14  Water ponds along this highway near the White Mountains in California. A desert spring also feeds wetland plants in a narrow strip adjacent to the highway.

Such a mesh of sampling locations can be laid out by pacing or by using a tape measure. The grid would be located within the boundaries and outside the boundaries of the potential jurisdictional wetland defined by the routine level evaluation (Figure 3.15). In this way, one can establish grid node loca‑ tions within the wetlands and in the uplands and then refine the boundary between grid nodes. Initially, one should lay out a 100‑foot length on the ground using a tape measure. Over time and with experience one can use pacing to estab‑ lish distances and the grid.* It is also possible to use steel or fabric dis‑ tance tapes or other methods of estimation that provide a field‑expedient way to measure distances and create grid sampling nodes separated at regular intervals. With a set grid mesh and grid size and directional references for the grid, it is possible to sample at an appropriate frequency and document the loca‑ tion of the samples in the field and on mapping products. The grid can be referenced to cardinal directions, fence lines, or other reference points via a *

This can be done by determining the average number of paces required to cover 100 feet of distance. This “calibration” should be performed by each individual undertaking the wetland study. Repeat this calibration procedure several times to determine the average number of steps per 100 feet of distance. Afterward, one can lay out 100‑foot lengths in the field on a reliable basis by pacing.

Methods

37

FIGURE 3.15  Sometimes water is present and ponded where it is unwelcome. Wildlife and wetland plants exploit the presence of unwelcome waters along this roadside in San Diego County, California.

compass. It will be possible to relocate the sample sites for later inspection by USACE personnel. It may be necessary to revisit the field to locate the jurisdictional bound‑ ary because they are often found between the sample points. In essence, it is necessary to interpolate between the points to fix the boundary. If the char‑ acteristics of the wetland boundary are not clear, sample soils and plants to determine the actual boundary as it is found between the sampling points of the 100‑foot grid. Be sure to “flag” or monument the individual sample points so that they can be checked at later field inspections. Surveyor’s tape, Mylar tape, or other permanent flags should be employed. Time and weather are hard on these materials and care should be taken in selecting materials that will last. Often, it may be many months before a given property is inspected, or it may never be necessary to inspect a property. It is still important, however, to be able to relocate the sampling sites at a later date. A request for an inspection by the USACE may be encountered at any time, and the elements of the field sample should be preserved to facilitate a response to questions posed by USACE.

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Practical Handbook for Wetland Identification and Delineation

It is also desirable to measure with a tape or pace from a given sample point to adjacent examples and evaluate whether the grid system is square. This allows one to determine whether individual points are out of position, and it facilitates correction of misplaced samples or lost points at a later date. In certain instances, it is desirable to use survey methods to establish the grid and create a surveyed map. Suitable techniques are discussed later. At each individual sample point or grid node, it is necessary to col‑ lect detailed information on soils, hydrology, and plants. Data should be recorded on field sheets or memo pads. The data can be presented later on the appropriate forms supplied in the Wetlands Delineation Manual (USACE 1987). In particular, forms B-2 and B-6 have been useful, and now examples like the Wetland Determination Form are useful (USACE 2010a–f). They provide adequate space for the recording of plant, soil, and hydrological measures on the form (Lyon 1993). 2. To evaluate wetland hydrology and subsurface hydric soil conditions as well as soil type and characteristics, one should dig a hole. This can be done with a shovel at the grid sampling site. The sampling hole should be deep enough to evaluate the top eighteen or so inches of the soil profile and hydrology (Figure 3.16). It may be sufficient to use a soil probe to evaluate soils, but it is much more difficult to observe soil characteristics mentioned below. In addition, a shovel hole or pit will remain for many months, and the location of a given sample can be inspected by regulatory personnel at a later date. Observe the excavation hole for standing water or seepage of water into the hole from the bottom or from the sides. Observe the conditions for fif‑ teen to twenty minutes after the hole is dug. One may wish to dig holes at several nodes and rotate around the site to observe them over time. This can be accomplished by checking the hole after a certain time period has elapsed while one is conducting other evaluations at sample nodes nearby. Note the hydrologic conditions. If water has seeped in, note the depth or distance from the soil surface to the water seepage surface and make notes. Also, check for gley or very wet soils resulting from very anaerobic condi‑ tions, sulfur or methane smell, and other indicators of wetland hydrology. Check for surface manifestation of wetland hydrology (Figure  3.17). This would include rafted debris, “fat‑based” tree trunks, sediment‑stained leaves, or dark and wetted leaves or duff. 3. Describe the soil type found at each sample point. This could include gen‑ eral soil textural conditions, soil levels or horizons, and soil colors. Record whether sample points have similar or dissimilar soils to those indicated by the county soil survey. These soil evaluations should include checking the Munsell Color Charts (Munsell Color 1990) for color, value, and chroma and checking for iron oxide mottling, the presence and depth of organic matter and organic soils, and the presence of manganese reduction products and/or grey or gley deposits.

Methods

39

FIGURE 3.16  Salt cedar is a real problem in many states. It effectively kicks out native plants by depositing salt in adjacent soils. The plant provides limited forage for local wildlife. This example is from along the Colorado River in Arizona.

Be sure to sample each soil layer encountered and record your findings. These layers are commonly called the “A” horizon or top soils, “B” horizon or subsoil, and the “C” horizon or parent material (USDA 1962, 1975, 1991; Foth 1990; Richardson and Vepraskas 2007). For jurisdictional purposes, soils that exhibit more than one of these indicators, such as standing water or seepage, dark Munsell chroma (/2, /1), lots of mottling, thick layers of high‑organic‑matter soils, gleyed soils, or other products from highly anaerobic soil chemistry conditions, will be considered to be evidence of a hydric criterion (USACE 1987). 4. One should check for indicators of wetland hydrology such as seasonal high water conditions (Figure 3.18). Such conditions are usually defined as 7 to 14 days’ duration of flooding or high water table per year during the growing season. In other manuals or proposed manuals, these periods may vary between 15 days of flooding or 21 days of very high water table. These measures of duration of flooding may change in the future, so be aware of current requirements. Currently, the interpretation is two weeks

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Practical Handbook for Wetland Identification and Delineation

FIGURE 3.17  The end of a culvert provides a common source of periodic water where wet‑ land plants can develop and flourish.

FIGURE 3.18  Wetland plants can develop wherever water appears. Impoundments, like this one behind Boulder Dam in Arizona, often drown other riverine system features, but new wetlands can quickly develop.

Methods

of standing water or subsurface saturation during the growing season period as defined by the USDA soil survey for the county. Record whether the soil and surrounding landscape exhibit hydrologi‑ cal indicators. At each sample point, note flood markings or rafted debris lines, shallow root systems, wet and/or poorly decomposed plant materials, adjacent stream courses, and other indicators of wetland hydrology men‑ tioned in the Wetlands Delineation Manual (USACE 1987). In particular, look for a surface layer of undecomposed leaves and/or an absence of plant growth compared to adjacent areas or silt and clay deposits on leaves and tree trunks. 5. Evaluate the plants found at the sample site. The ground, shrub, vine and tree layers of the vegetation need to be described by the plant species that are dominant. Dominance is defined as 50% or more vegetation in the veg‑ etative layer are composed of facultative plants (FAC), facultative wetland plants (FACW) or more wetland‑loving plants (obligate or OBL). It has been found to be appropriate to evaluate the ground layer of veg‑ etation within a circle of radius of 10 feet centered at the sample point. The shrub layer should be described within a 20‑foot radius and the tree layer within a 30‑foot radius circle about the sample point. These radii have proven useful in wetland delineations and are based on suggestions in the Wetlands Delineation Manual (USACE 1987). This approach may be not be suitable if there are changes in future interpretations or manuals, due to local or regional conditions or due to the requests by other, so be aware of current requirements (Wakeley 2002; USACE 2010a–f). It is also necessary to estimate the relative abundance of each dominant plant species based on the relative prevalence of the given species. This is then compared to the relative percentage abundance or cover to the total quantity of vegetation at each sample point. This may be done by visual estimates, particularly if the observer is experienced in this method of estimation. The Wetlands Delineation Manual (USACE 1987; USACE 2010a–f) and other sources provide addi‑ tional dominance estimating procedures, but the visual estimate is both field expedient and accurately performed with practice. 6. The plant species data and the dominance estimates in percentage are used to identify the common plants at the sampling site. The wetland determina‑ tion procedure is presented in the Wetlands Delineation Manual (USACE 1987) and other supplements and sources (Federal Interagency Committee for Wetlands Delineation [FICWD] 1989; USACE 2010a–f), and the same or similar techniques are addressed in scholarly books or journals (Mueller‑Dombois and Ellenburg 1974; Lyon 1993, 2001). The procedure consists of determining whether 50% of the dominant plants have a high probability of occurring in wetlands (USACE 1987). The National List (Reed, 1988; http://www.wetlands.com/fws/plants97. htm) records the plants species and their agreed‑upon categories of prob‑ ability of occurrence in wetlands. Wetland plant species do vary in their probability of occurrence from one region to another, and hence the

41

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Practical Handbook for Wetland Identification and Delineation

probabilities are listed by the geographical region of interest. One uses the intermediate‑level recording sheets to record and sum the percentage cover‑ age of dominants that are listed as types facultative FAC, FACW, and OBL wetland plants species. 7. It is desirable to plot the locations of the sampled points on an available topographic map or engineering‑style planimetric or plan map or GIS map and to supply the boundaries of any jurisdictional wetlands (Figure 3.19). It may also be desirable, though not necessary, to present the boundaries of any hydric soils encountered on a separate map. These boundaries will make a nice contrast with any USDA hydric soil boundaries shown on the soil survey map. 8. To make a finding that an area is a jurisdictional wetland it is necessary to (1) have hydric soils, (2) have evidence of wetland hydrology, and (3) find that 50% or more of the dominant plants have a high probability of occur‑ ring in a wetland. All three of these criteria must be satisfied. Failure to meet one or more of the three criteria means that the area is not considered a wetland for jurisdictional purposes. Use other sources of data and field checks to determine the adequacy and accuracy of mapped jurisdictional wetland boundaries. Check and recheck your work. Adjust boundaries as necessary and determine the acre‑

FIGURE 3.19  Flood waters can create temporary riverine systems and establish conditions for more permanent wetlands. Desert systems are particularly well adapted to both activate and procreate in a short time span and even in alternate years if necessary. The scene is from Santa Clara River floodplain in Tucson, Arizona.

Methods

43

age of the actual jurisdictional wetlands. Supply the acreage estimate in the comprehensive/intermediate wetland assessment report. It is also desirable to check and pace the location and size of the wetland and ensure that its characteristics have been correctly mapped. Double‑check the dimensions of the wetland by pacing or other measurement technique to ensure that the area estimates are correct. It may also be necessary to flag the actual boundaries of the wetland on the ground, to facilitate surveying of boundaries or to facilitate inspections by the USACE. 9. Allow a period for evaluation of products by the client. Incorporate com‑ ments and criticisms and produce final products identifying jurisdictional wetland areas. At this point the wetland report may be filed or the information used in planning and management of the wetland resource. A sample intermediate‑level report is provided in Lyon (1993). Please note that in USACE (1987) Appendix C in the reference is outdated as are some other paragraphs and equivalent information must be obtained from regional wetlands‑related offices such as USACE or Regional Supplements to the Corps of Engineers Wetland Deliniation Manual (USACE 2009a–b, 2010a–f). These products and a report summarizing the methods used in their production may be submitted as a wetland assessment to the U.S. Army Corps of Engineers in support of CWA section 404 permitting activities. Note that the requirements for and types of permits as well as reporting requirements change over time. It is desirable to become familiar with the permitting requirements in the area of study before work begins. Follow the requirements and deadlines such that permitting is an orderly process. The information and methods provided above lend some insight and appreciation of the complexities involved in wetland evaluations. Comprehensive/intermediate‑level methods and reporting can be useful in a number of applications, and they provide a good, general model of how to acquire and present data for determination of jurisdic‑ tional wetlands. The comprehensive/intermediate‑level report is very suitable for permitting activ‑ ities and often represents the minimum of detail necessary to support a finding of jurisdictional wetlands, depending on reporting requirements. It is particularly desirable to document the preconstruction conditions of a given property using these techniques, even if no jurisdictional wetlands are found. Completion of a comprehensive intermediate report provides good documentation if questions arise after initiation of construction, and it is good evidence of due dili‑ gence on the part of the landowner in fulfilling responsibilities related to wetlands.

COMPREHENSIVE ADVANCED-LEVEL PROCEDURES In certain situations it may be necessary to use additional techniques to augment those presented above or described in the Wetlands Delineation Manual (USACE 1987). The need for comprehensive procedures to supply great detail may be mani‑ fest by the complexity of the wetland or the complexity of the terrestrial and aquatic interface.

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Practical Handbook for Wetland Identification and Delineation

Detailed, comprehensive/advanced‑level procedures may be necessary because the status and extent of the wetlands are in contention. Other needs may be dictated by the presence of a unique plant or animal species that uses the wetland as a habitat or home and hence wetland characteristics must be detailed for more than the sim‑ ple needs of identifying a jurisdictional wetland and CWA Section 404 permitting activities. There may also be local or state requirements or requirements of water quality reporting and permitting within a state based on CWA Section 401 “State Certification of Water Quality.” All are reasons to add more detail to the evaluations. The following chapters supply a number of methods that may be used to augment the comprehensive/intermediate‑level procedures and reporting. Some of these meth‑ ods are defined as comprehensive‑type methods in the Wetlands Delineation Manual (USACE 1987) and other scholarly works (e.g., USACE 2009a–b, 2010a–f). Other approaches are suggested by the authors or colleagues based on personal experience. All these techniques provide a higher level of detail and can be used to customize the wetland evaluation process to meet the unique characteristics of a particular site or jurisdiction or both.

4

Additional Background and Details

SOILS Hydric soil characteristics need to be understood and appreciated to supply good identification and delineations. Soil conditions need to be evaluated using methods from the Wetlands Delineation Manual (U.S. Army Corps of Engineers [USACE] 1987) and other manuals and sources to adequately address the hydric soils criterion in determination of jurisdictional wetlands. Wetland soils are formed wherever water stands for a period of time or where there is a frequent presence of water (Figure 4.1). These conditions may occur in or adjacent to a stream, creek, or ephemeral pond. The mechanisms for development of wetland soils and the reasons that wetland plants are found on these soils are related to soil characteristics as influenced by waterlogging. The chemistry of waterlogged soils changes over time. As explained previously, the oxygen found in water‑filled voids between soil particles is quickly exhausted by biological and chemical oxygen demands. Once the oxygen is gone, it is slow to be replaced. Little can diffuse through the water to replace that which is gone, and the anaerobic or air‑free condition begins. In the absence of oxygen, the soil’s electrochemistry changes greatly. No longer is oxygen available as an electron acceptor in reduction–oxidation or “redox” reactions (Richardson and Vepraskas 2007). Depending on the duration of inundation, various elements including sulfur and nitrogen become the electron acceptors. Iron, manga‑ nese, and other electron donors are also involved, and they change their “oxidation states” (Foth 1990). The duration of waterlogging has a great influence on the variety and quantity of anaerobic soil chemical products found in soil. Over time, change in the elec‑ trochemical environment of soils results in the production of different compounds compared to those found in air‑rich or aerated soil environments. These oxygen‑free or oxygen‑scarce areas are anaerobic and result in reduced forms of iron and manga‑ nese, as well as different forms of other elements, compounds, or ions. Other examples of results from waterlogging will be familiar to the reader. They include the presence of methane instead of carbon dioxide, ammonium ions instead of nitrates, and hydrogen sulfides instead of sulfate ions (Richardson and Vepraskas 2007). Indeed, conversion of chemicals from one form to another is a major value and function of anaerobic soils and wetlands. The soils will remain largely without oxygen as long as they remain waterlogged. They return to the oxygen‑rich or aerobic condition after the water has drained out 45

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Practical Handbook for Wetland Identification and Delineation

FIGURE 4.1  One can take advantage of existing excavations to examine soil character‑ istics, learn about soil conditions and types, and gain proficiency in soil identification and classification methods.

of the soil and air again fills the voids between soil particles and cracks in soil. After the water drains from the soil and oxygen in air is again available in the system, the soil chemistry changes to that of an aerobic system as a result of the electrochemistry of oxygen (Good et al. 1978). What remains in the soil horizon is the record of the general presence of water and period of duration of water logging. The record is in the form of chemical com‑ pounds or deposits in the soil horizon resulting from anaerobic conditions. The remaining chemical products can be used to judge whether soil waterlogging has occurred at a given site at some time of year in the past. A common condition found in hydric mineral soils is the presence of iron oxides. These are deposited after air is restored to the soil system following waterlogging. The waterlogged and anaerobic soil conditions initially cause iron compounds that are normally insoluble to become soluble. Hence, iron ions become available in the anaerobic waterlogged system and can be transported. When the water table drops and water drains from the soil horizon, the iron ions and other compounds are converted to oxides in the presence of “new” oxygen in air and soil air voids or pores. These iron oxides are insoluble in oxygenated water or in the presence of air and are deposited in the voids and cracks of the soils, creating a series of irregularly distributed, “rusty” colors called iron oxide mottling (U.S. Department of Agriculture [USDA] 1991). The presence of mottling is a good indicator that the soils have been waterlogged at some time in the past. They may have been deposited during the non‑growing sea‑ son or may have been deposited several years ago during periods of higher precipita‑ tion, snow melt, or other conditions that cause waterlogging (Figure 4.2). Iron oxide mottling can also occur at a variety of times during the year. So, it is not de facto evidence of long‑term waterlogging during the recent growing sea‑

Additional Background and Details

47

FIGURE 4.2  Field personnel use various tools to check for soil conditions. A common shovel is used here to dig a hole or small pit. The advantages to the shovel method include speed of excavation, quick collection of a good quantity of material to be examined, and shovel holes can often be easily relocated much later in time.

son period, because they may have developed during the non‑growing period or developed during a particularly unusual precipitation year. The quantity of mottling may be interpreted as being somewhat related to the frequency of waterlogging. Mottling varies greatly in size distribution and in color. It may appear as a fine distribution of small particles or may be large, nonrandomly distributed deposits. Mottles may also vary in their color. This variability can result from local chemical conditions, frequency and duration of flooding, and other vari‑ ables such as the availability of different elements or compounds. It is desirable to describe whether mottling is present in the soils and to char‑ acterize their color. Mottling may be characterized by comparing them to the Munsell Color Chart (Munsell Color 1990) and recording hue, value, and chroma (Figure 4.3). One should conduct this evaluation for all visible soil layers or horizons. It is also desirable to record the distance from the surface to where they are deposited (Figure 4.4). Long periods of anaerobic conditions produce materials that are indicative of severely waterlogged soils. For example, the presence of manganese deposits, called concretions, in soil horizons results from waterlogging of long duration. In frequently flooded or constantly waterlogged soils there are formations present called gley deposits or gleyed soils. The presence of loose grey soils and grey depos‑ its in soil voids results from long periods of anaerobic conditions (Vepraskas et al. 2004; Richardson and Vepraskas 2007). These grey deposits or gleys have distinct, though not outstanding, colors, and they may be described with a Munsell Color Chart (Munsell Color 1990) specific for gleys (Figure 4.5). Hydric soils are often characterized by a relative abundance of organic matter, and organic matter decays in upland soils (Figures 4.6, 4.7, and 4.8). This occurs because decomposition of organic matter proceeds at one fourth the rate in waterlogged soils

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Practical Handbook for Wetland Identification and Delineation

FIGURE 4.3  Next to this shovel hole is a Munsell Color Chart. The chart is a matching tool that can be in the field. The delineator can create a soil matrix color determination for each layer or horizon removed from the hole. A soil matrix can be developed for each sampling site or node in a sampling grid, creating a comprehensive soil survey of an area.

FIGURE 4.4  A common yardstick can show the depth of each hole, supply scale in pho‑ tographs, and document the depth of each soil layer or horizon. The Munsell Color Chart is used to describe the soil matrix color and chroma of each soil horizon and any mottling or other soil color conditions.

Additional Background and Details

49

FIGURE 4.5  Delineators also check for the presence of mottling and other hydric soil indi‑ cators. Mottled colors or highly anaerobic gleyed soils are characterized using the Munsell Color Chart. Seepage and drainage conditions are also noted as part of the wetland hydrology assessment.

FIGURE 4.6  Here is a dry wetland area with little water in the hole or on the soil excavation surfaces. The plants appear to be wetland‑loving species and the soils look mineral in nature as opposed to organic.

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Practical Handbook for Wetland Identification and Delineation

FIGURE 4.7  Photographing each sample location is always a good idea. Note the shovel for excavation and for scale and the notebook with large lettering to denote the sample node location of row “D” and column point “0.” Sites can be marked or flagged nearby to make it easy to identify the site at another time.

FIGURE 4.8  Typical upland soils from a site in central Ohio. Note the presence of leafy plant residue on the surface of mineral soils with some mottling.

compared to soils that are aerobic or aerated (Foth 1990; USDA 1991). As a result, the organic matter builds up and over hundreds of years an organic‑rich soil is devel‑ oped (Figure 4.9). Organic matter has a very low reflectance of light and tends to stain soils and make them very dark in color (Lyon 1987, 2001). This dark staining can be viewed by digging up the top 12 or more inches of the organic soil. This dark color is com‑ monly an indicator of hydric soils, and the condition can be judged by low (/2, /1) chromas on the Munsell Color Charts (Munsell Color 1990).

Additional Background and Details

51

FIGURE 4.9  These soils are mottled, which appears as a light grey against the white of the mineral soil tones in this photo. The surface is mostly duff or peat composed of organic material from deciduous leaves.

FIGURE 4.10  Flagging of some type can help locate the sample site or node. Pictured here is plastic packing tape marked with a location using permanent ink.

Longer‑term waterlogging of soils (see Figure 4.9) also results in the presence of undecayed organic matter that still shows plant structures or peat, and reduced forms of sulfur and carbon. These sulfur‑based compounds include examples that have well‑known odors. Highly anaerobic conditions can be sensed by the “rotten egg” smell. Reduced carbon can be sensed by the “swamp gas” smell of methane. Sampling these soils is usually a simple matter of digging or probing the soil (Figure  4.10). In very wet or submerged soils special techniques may be necessary

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Practical Handbook for Wetland Identification and Delineation

(USDA 1991; Richardson and Vepraskas 2007). These techniques really are more for research than permitting, because soils that are very wet or submerged meet the soil hydric criterion and may not require extensive sampling to establish a record of an obvi‑ ous condition.

SOIL SURVEYS County soil surveys were developed by the soil scientists of the USDA Soil Conservation Service (SCS) and later the Natural Resource Conservation Service (NRCS) in cooperation with state university and state resource agency soil scientists. They are based on extensive field‑ and office work. In a preliminary evaluation of a property, the soil survey may be very helpful in identifying hydric soil types and potential jurisdictional wetland areas. The level of detail of a soil survey is good but necessarily general in nature. Soil surveys include soil type maps that consist of soil boundary delineations on copies of black‑and‑white aerial photos (USDA 1962, 1975). This “photo map” product can be easy to use because the aerial photo mapping base records a lot of information. The photo maps are a record of actual conditions rather than a stylized rendition of conditions typically supplied by map symbols on maps (see Figures 4.3 and 4.4). Soil survey products also supply detail on cultural or planimetric information. These details can be used to locate a given property on the soil survey maps. Once the property is located, the reader should note the presence of soil types indicated by soil type boundaries and map codes. A list of these types should be made, and the characteristics of each soil type should be evaluated from the descriptive part of the soil survey. Soil types are described in the county soil survey by the name of a location where the particular soil type was originally described. For example, Houghton muck soils were first described near the town of Houghton, Michigan; a Kokomo soil near Kokomo, Indiana; and so forth. The system is further detailed in the Soil Survey Manual (USDA 1962) and other references (USDA 1975 2010). Soil types are also labeled by agricultural soil scientists using the Series Soil Classification System. It is hierarchical in levels of categorization and its system of labels. The soil survey uses these levels of detail to describe the characteristics of soils. Under the name of each soil type, the soil survey lists a variety of information that characterizes the soil. Included in the narrative of the soil survey and in the tables are soil particle size distributions or soil texture. The general hydrological characteristic descriptions of soils are addressed, as well as the agronomic, forestry, and engineering‑related soil characteristics. Tables provide information on depths and types of layers or horizons; soil physical characteristics; typical crop yields for the soils; suggested land uses such as farming, forestry, or wetland habitat for each soil; suggested tree or shrub plantings; soil and nutrient characteristics; and a great deal more. Though the information in a county soil survey is general, it is of good quality, and available for almost all counties in the U.S. The survey is uniform in content and

Additional Background and Details

53

detail, and it is free in book form. It is an ideal routine‑ or reconnaissance‑level tool for planning and management. Hence, it is often used by groups for that purpose, and it is certainly used as an information source by the USACE. A disadvantage of soil surveys and their level of detail is that many of these products were completed some time ago. Often, users do not recognize this fact and make decisions based on old information. Any errors of this nature become obvious with field visits. Soil surveys were not developed and produced to function as a regulatory tool. They may be involved in regulatory decisions and enjoy widespread availability. As a practical matter, the presence of hydric soil types on the soil survey of a given property can be a “trigger” for an increased level of attention by regulatory agencies. They do not within themselves present the best product for jurisdictional evaluations and as such should be used for routine‑level evaluations.

MUNSELL COLOR CHARTS Munsell Color Charts (Munsell Color 1990) for soils provide a good, qualitative tool to estimate color characteristics. The results of physical and chemical processes that create soil types and soil horizons can be recorded in the field or in the lab using Munsell Color Charts. The color characteristics of soils are conceptualized as color hue, value, and chroma. Hue refers to the general color, value refers to the depth or intensity of color, and chroma refers to the strength or darkness (Foth 1990). A Munsell Color Chart evaluation of soils involves three steps: (a) selecting the correct color and hue page; (b) using the page in the field to identify soil color value characteristic; and (c) identifying the chroma or strength of color along the right axis of the page. Munsell Color Charts should be used to record the general color characteristics of the soil horizons encountered. One measures the background color of the layer or soil “matrix” color. One might record two such estimates for each sample site; one for the top layer of soil or “A” horizon and one for the subsoil or “B” horizon. As discussed previously, certain chemical products of aerobic and anaerobic con‑ ditions are manifest as colors displayed by mottled or gleyed soils. If mottling or gley soils are present, additional records of color should be made to document either of these conditions, and to do so for each horizon. One can find the general colors of a given soil type listed in the soil survey. The color swatch can be examined in the book of Munsell Color Charts, and the hue page can be selected. On a given Munsell Color Charts hue page (e.g., 10YR or 5YR), the color choices will be presented as a matrix of values and chroma for each hue. Use the appropriate hue card to make your estimates in the field. If difficulty is experienced identifying the best hue card to use, one should again check the soil sur‑ vey for the appropriate choice of hue page for the soil types mapped on the property. If mottling or gley areas appear in the soil matrix, Munsell Color Charts should be used to estimate their color. There exists a special Munsell Chart for gley soils alone, which is optimized for the blue‑grey colors of gley. This tool is currently

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Practical Handbook for Wetland Identification and Delineation

of limited use, because the presence of gley is indicative of hydric conditions and detailed recording of their characteristics may be of limited interest only. Adequate detail can be supplied with the soils Munsell Color Charts if the special gley chart is unavailable. The characteristic colors of a given wetland soil and its soil layers or horizons are recorded in the county soil survey. In general, soil color chroma of /1 or /2 below are indicative of wet soils and a hydric condition. The Wetlands Delineation Manual (USACE 1987) and other manuals indicate that soils with these chroma should be categorized as hydric and they meet the soil hydric criteria for jurisdictional wetland areas.

PLANT MEASUREMENTS A given plant’s abundance and distribution will be largely determined by its toler‑ ance to wetland soil and hydrology factors. As a result, wetland plants are a valuable indicator of wetland conditions in a given area. Plants respond to many environmen‑ tal parameters such as flooding, topography, soil type, soil nutrients, and general water quantity and quality conditions. Because of this capability to grow in these environmental conditions and variability of habitats they grow in, plants can be used as indicators of potential jurisdictional wetlands and actual wetland areas. Often the change in wetland plant types across a wetland area is a gradual one, with overlapping areas of different plant species that tolerate slightly different wet‑ land soil and hydrological conditions. The presence or absence of certain plants can be used to help classify these wetlands as to type and map these types of wetlands. For regulatory purposes, the dominant plants need to be identified at the species level (see Figure  4.5). Dominance is defined in the Wetlands Delineation Manual (USACE 1987) as the relative abundance of the most common plant species in a given layer of vegetation. The abundance of each dominant plant species needs to be estimated in the field. Only the most dominant species need to be estimated. However, it is good to note the relative abundance of all plants in the sampling area. This would be true of any obligate (OBL) or facultative wetland (FACW+; Reed 1988; http://www.wet‑ lands.com/fws/plants97.htm) plants, which may not be dominant but are certainly of interest. The tree, shrub, vine and ground layer of vegetation should be sampled (see Figure 4.6) if plants are found in each of these layers. One method is to describe the type and estimate the relative quantity of plant species and their dominance. Dominance can be estimated by visual determinations of percentage areal cover of the plant layer or stratum or number of stems/trunks in a given vegetation layer. Relative abundance can be estimated in 5 or 10% increments totaling a 100% relative cover or abundance for a given vegetation layer. This can be done by visual estimate, by counting stems/trunks, or by relative size or girth of the tree species. The level of detail (5/10%) of vegetation can be at the choice of the user. The Wetlands Delineation Manual (USACE 1987) and other scholarly works (USACE, 2009a–b, 2010a–f) and the experience of the author’s suggest that estimates for the tree layer should be made within 30 feet of the sample point. A 20‑foot‑radius

Additional Background and Details

55

circle from the sample point should be sampled for the shrub layer and 10 feet in each direction from the center of the sampling point for the ground or herbaceous layer. Knowledge of plants is highly desirable. One need not be a botanist or have extensive training. The Wetlands Delineation Manual (USACE 1987) states that the person evaluating the plants should be able to identify the dominant plant species present in the area (see Figure 4.7). In any effort, a variety of plant identification books should be used for identifying or “keying” plants to their species names. One should make use of local plant books, because they often have books with maps of plant species distributions. In the beginning of any effort, it may be desirable to collect plants in the field. A good approach is to refrigerate them until there is time to identify the plants at the office. Once an individual is thoroughly familiar with the dominant plant types, they may be described in the field without collecting plants at each individual sample point (Figure 4.11). Books with color photographs of the plant species of interest can be invaluable, along with plant identification keys. One needs to employ photos in addition to traditional keys to help insure a correct determination. The combination of local plant distribution lists or maps, plant photos, and plant keys will greatly assist the reader in correctly identifying plant species. Due to the inherent difficulty of plant identification for non‑botanists, it is impor‑ tant to use a number of books and sources (see Appendix). At a minimum, one needs a wetland plant book (e.g., Fassett 1957; Hotchkiss 1972), a tree book (Harlow 1957; Sargent 1969; Miller and Lamb 1985; Mohlenbrock and Thieret 1987), a shrub book (Billington 1968), books about non‑woody plants (Dana 1963; Peterson and

FIGURE 4.11  The flagging will stay up for about a year with the adhesive keeping it in place. It can be knotted to stay in place longer. Later, it will fall to Earth and can be found.

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Practical Handbook for Wetland Identification and Delineation

McKenny 1968; Courtenay and Zimmerman 1972; Mohlenbrock 1987; Forey 1990), books on grasses and sedges (Fassett 1951; Hitchcock 1971; Knobel 1977), as well as books about a variety of plants (Britton and Brown 1970; Agricultural Research Service 1971). A variety of books are necessary to address the mix of upland and wetland plants that occupy the interphase between each environment. Delineation of wetlands occurs at the edge and hence a mix of publications is required. Additional books that can be helpful in plant identification are listed in the Appendix. Plants typically have one or more names in common usage, known as common names. These may be used in describing the plants in the field and/or in the report of the project. Plants also have a scientific name. It is best to employ scientific names in the wetland report and to do so with plant names on the record sheets (e.g., Lyon 1993) that were supplied in the Wetlands Delineation Manual (USACE 1987 and supplements USACE 2009a–b, 2010a–f). The scientific names have two parts written in Latin. The first word is the family or generic name. Plants are grouped into families that are thought to have a common evolutionary ancestry. This is based on plant physical characteristics or morphology. The second name is that of the individual plant or plant species in the family. Until familiarity with common or scientific plant names is established, use general names or identification labels in the field. This labeling approach allows straight‑for‑ ward identification in the field and allows one to record the dominance level and then determine the actual species scientific name later in the office. Consider drying selected examples of plants. This may be done in a plant press of layered cardboard and blotter paper, all secured by straps to flatten and help dry the plants. These plants may be useful at later time, as a record to verify their identity and satisfy questions of critics or regulators. The plant criterion for a jurisdictional wetland is determined by enumerating only the dominant plants that have the highest probability of existing in wetland areas. These are the facultative (FAC), FACW, and OBL categories of plants. A given area is determined to be a wetland for this individual jurisdictional criterion when the total abundance of FAC, FACW, and OBL plants exceeds 50% of the total of dominant plants found at a given sampling location on the site (Reed 1988; http:// www.wetlands.com/fws/plants97.htm). A fundamental problem for analyses of wetlands is that some plants “evade” harsh winter growing conditions through death or dormancy. As a result, there is an absence or lower abundance of structures like leaves or flowers to assist in their iden‑ tification. The absence of these and other plant features can make plant identification difficult (Figures 4.12 and 4.13). Plant species keys have been developed for winter conditions (Harlow 1946, 1947; Symonds 1958, 1973; Trelease 1967) and can be employed, but identification is much slower. One identifies plants from the plant residue that remains. It may be impos‑ sible to identify or locate some plants, particularly for the ground or herbaceous layer, if the plants have decomposed or are otherwise absent (Figure 4.14).

Additional Background and Details

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FIGURE 4.12  Coastal and back barrier wetlands abound near Galveston Island, Texas. Wetlands grow along highway corridors, utility corridors, the Houston Ship Canal, and around other vestiges of human activity near water.

FIGURE 4.13  Even in the most well‑manicured landscapes, like this one near a famous golf course in La Jolla, California, remnants of wet areas may begin to look like wetlands. Likely a palm is missing and water has seeped into the spot.

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Practical Handbook for Wetland Identification and Delineation

FIGURE 4.14  Water ponds above this rock wall. Some water leaks down the vertical sur‑ face. Plants take hold in the crevices of the rock. These areas may demonstrate all three wetland criteria, but a delineator would need to test to be certain.

5

Additional Methods and Considerations

Wetlands exhibit a variety of conditions that may not be easy to identify and char‑ acterize. Conditions may require application of methods that supply detail beyond those in previous chapters. The following methods and considerations may be helpful in a variety of situations (Figure 5.1). Their implementation, along with intermediate‑level examples of meth‑ ods, will facilitate the assessment of wetlands and their variable characteristics. The identification and delineation of jurisdictional wetlands should employ a combination of methods. Here, information is supplied on individual methods and scientific or engineering approaches that may be useful in a variety of situ‑ ations (Figure 5.2). The best approach for evaluation of a given property would be to combine routine‑ and intermediate‑level techniques and to draw upon the following methods to supply additional information as dictated by the problem at hand.

TOPOGRAPHIC MAPS Maps and their digital counterparts are useful for a variety of needs. These can include reconnaissance of the site, displaying draft and final results of analyses, stor‑ ing information in image or picture form, calculations of dimensions, and communi‑ cating results to audiences (Figure 5.3). Maps are designed to render a scaled version of reality. Often, they are referred to by the scale of a given measure in proportion or ratio form. For example, mod‑ erate‑resolution United States Geological Survey (USGS) maps have scales of 1:24,000, where one inch or one centimeter on the map represents 24,000 inches or 24,000 cm on the Earth’s surface. In general, moderate‑resolution or course‑resolution maps are referred to as small‑scale products, due to the fact that the ratio is small. One can also remember this because features on the Earth’s surface appear “small” on the map. Conversely, engineering‑scale two‑dimensional maps or planimetric maps or three‑dimensional maps have details that appear large and have scales on the order of 1 inch = 200 feet or 1 inch-500 feet scale and objects on the Earth’s surface appear “large.” Hence, these images or maps are called large‑scale maps (Figure 5.4). Large‑scale topographic maps are usually available for sites to be developed. These large‑scale, engineering‑style maps are useful for delineation of wetlands as well as their traditional uses of calculating Earth movement activities or “cut and fill,” laying out pavements and sidewalks, and so forth. They present topographic detail of much higher frequency and quality than USGS 1:24,000 scale maps. 59

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FIGURE 5.1  A low‑altitude aerial photograph captures the variety of coastal wetlands. Note the presence of tree canopies in the top right evident from the texture and dark tones created by shadows from the canopy.

FIGURE 5.2  A river meanders across the landscape, creating irregular shapes in the land. Abandoned channels or meander scars appear lighter than active channels still full of water. Lakes or ponds often seem to have a white “outline.” Bare soils at the lake and pond edges reflect more light, thus creating the outlining effect seen in some aerial photos.

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61

FIGURE 5.3  Forested wetlands can be identified from this low‑altitude aerial image. Note the central dark shape of the tree canopy. From this altitude, it is possible to identify the trees as to forest community. At a lower viewing altitude, identification of species is possible.

FIGURE 5.4  Low‑altitude photographs can be very useful to delineators. A small digital camera, a rented aircraft, and a steady hand caught this image. Note the detail in the tree canopy. This can aid in tree species identification. The dark tone found along the lower chan‑ nel near the light‑toned beach or soil areas in the lower center is probably a small emergent wetland. Another emergent wetland appears to be located around the pond at the top right of the photo. The mottled light and dark area could be a mixture of wetland plants and soils near the shore.

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Large‑scale topographic maps are commonly made by surveying and photogram‑ metry techniques (Falkner 1994; Falkner and Morgan 2001). Generally, they are produced at scales of 1 inch = 50 feet, 1 inch = 100 feet or 1 inch = 200 feet. They are called large scale because the ratio fraction of scale is large compared to the ratio fraction of a 1:24,000 scale map (1 inch = 2,000 feet). A method to remember these terms is that objects appear larger on large‑scale maps. The ranges in vertical elevation of the landscape are presented as contour inter‑ vals. They can be used to characterize topography from these large‑scale maps. One can also evaluate topographic detail from 1:24,000 scale USGS quadrangles, but large‑scale topographic maps present more detail for evaluations of sites for wetland conditions (Figure 5.5). Topography is commonly presented either in 1 foot or 2 foot contours. In moun‑ tainous regions or for maps of small scale, the contour interval used maybe 5 or 10 feet. The actual interval depends on the general topography of the site and the needs of the project for detail. Two foot contours are fine for general design of projects. A 1 foot contour is nec‑ essary for finer details of project design, including cut and fill calculations, planning and design of storm sewers and water lines, and the platting of property for homes. Either contour interval on the large‑scale topographic map can be employed in wet‑ land evaluations. Large‑scale topographic maps can be valuable for presentation of the location of jurisdictional wetlands. This product makes an excellent record for permitting when maps of 1 inch = 100 feet or 1 inch:200 feet scale or larger are used. Such maps and wetland delineations may also facilitate highly detailed determinations of wetland areas.

FIGURE 5.5  Note the lighter‑toned area composed of relatively bare soils and non‑woody vegetation found on distributary levee deposits and in abandoned discharge channels. The dark‑toned and coarse‑textured areas in the top of the image are wetland and upland forests of this large‑scale image.

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63

FIGURE 5.6  Riverine deposits form islands surrounded by marshes, creating an abundance of habitat.

Large‑scale maps also indicate where detailed intermediate‑level sampling was conducted and facilitate later inspection of the site by regulatory personnel. They can also be employed to record the extent of hydric soils as determined in the field. In general, they make a very good base map and can be annotated with appropriate detail to make a product that is useful in permitting (Figure 5.6). USGS topographic maps are available for the United States at a variety of scales. The moderate‑resolution scale product is the 1:24,000 scale quadrangles, and these maps can be found for most of the continental United States (http://topomaps.usgs. gov/). USGS quadrangles may be used in reports to identify the general location of the site; the presence of adjacent streams, ponds, and rivers; and the general location of potential jurisdictional wetlands. They are also good for identifying adjacent resources of note, such as other large or significant wetlands or the pres‑ ence of navigable waterways or other large or significant waterways such as rivers and streams. Many people make use of these 1:24,000 scale maps in wetland reports, because the maps are nice products and readily available. The resolution is really too coarse, however, for recording the size of wetlands encountered in permitting actions. They are inferior to large‑scale maps for making determinations of wetland size or acreage. Potentially, large errors can be made due to the course resolution asso‑ ciated with the scale. They are certainly useful in the absence of aforementioned large‑scale, engineering‑style topographic maps but should not be substituted for such large‑scale maps. It is also desirable to obtain general‑purpose road and stream drainage maps of the region. For example, the connectivity of stream, gullies, and drainage system is important for locating the position of the resource upon the landscape and for evalu‑ ating jurisdiction issues such as connectivity or isolation. A variety of map and other geospatial data is useful for evaluations and should be obtained (Figure 5.7).

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FIGURE 5.7  Here light‑toned areas show soils covered with emergent plants and floating leaf species such as Nuphar. This combination of relatively bright soil reflectance and the reflectance off the waxy surface of plant leaf materials makes for a bright contrast with rela‑ tively dark‑toned and shadow forested areas adjacent.

Use of the topographic maps allows the relative topography of the site to be evaluated. This fosters identification of low spots where water may pond and assists in the identification of streams, creek, gullies, floodplains, and other conveyances of water. This sort of information is valuable for locating the water conveyances and the connectivity of water courses that make up the drainage of the landscape. These water‑formed landscapes or low areas may be potential wetland areas, and it is desirable to use maps to locate them and investigate their presence in the field. A variety of techniques to evaluate the drainage pattern or connectivity of water conveyances can be found in Lyon (2003) and Maidment (2002), among others. Other mapping data can also be used to locate the property very clearly for the reader. This is accomplished by supplying a copy of the road map with the prop‑ erty location indicated. Road or county maps are also useful in developing a verbal description of the property location; that is, a description of the property as it is referenced to streets. Certainly, a legal description of the property is also valuable, though such a detailed description may not be necessary for some activities, includ‑ ing permitting, where wetlands are described within the parcel. Increasingly there are thematic maps available for many areas on a local basis. These and other types of maps, or reports containing maps, may be encountered in the search of available information. As stated previously, it is important to make use of all available data sources in making an assessment. Hence, one should use all mapping information to ensure a complete data base for analysis (Figure 5.8). This approach also allows one to take advantage of available and “free” information and insures that no important mapping or wetland details are missed or ignored. The numerous Web sites with mapping or geospatial data facilitate such a search for detail.

Additional Methods and Considerations

65

FIGURE 5.8  This image, shot from a commercial aircraft window, captures the relatively low topographic areas frequently occupied by wetlands, bare soil, or saline soil areas. It also captures adjacent human activities such as farming and sewage treatment. These human activities are often sited so that effluent after treatment can flow downhill to the wetlands.

Thematic maps usually have topical information such as geologic types or themes, land cover or land use themes, or land ownership themes. The National Wetlands Inventory (NWI) maps are a type of thematic maps, as are land cover maps of for‑ ests, agriculture, urban, and suburban areas. Increasing, these maps are encountered and can be useful in this work.

AERIAL PHOTOS AND REMOTE SENSOR IMAGE DATA In a similar manner to maps, aerial photos or images provide a vertical or synoptic view of wetlands (Roller 1977; Lyon 1979; K. Lee and Lunetta 1995). Depending on the altitude where the photography was taken, photos can be used to identify wetland plant species and/or groups of plants known as wetland plant communi‑ ties (Figure  5.9). Photos can also be interpreted for hydrological conditions (Lyon and Drobney 1984; Lyon et al. 1986; Lyon and Greene 1992; Garofalo 2003) and provide a valuable record and source of data for assessment of the year‑to‑year or season‑to‑season variability in wetland hydric conditions (USACE 1987). Many wetland types exhibit distinct light reflectance characteristics in the visible or infrared portions of the electromagnetic radiation spectrum. Wetland soils and water have distinctive reflectance characteristics that can be used to identify their presence and condition. Distinct shapes or patterns are also found in association with wetland site conditions (Figure 5.10). All these characteristics can be used for identification, and they are evident on aerial photos as different colors, tones, shapes, and textures or patterns (Lyon 1979, 1981, 2003). Aerial photos are also valuable as a historical record. They are a permanent measure of conditions at one point in time (Figure 5.11). Aerial photos have been acquired of the United States on a regular basis since 1935. It is common to find a series of dates of photographic coverage for a given site, beginning before World

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Practical Handbook for Wetland Identification and Delineation

FIGURE 5.9  From this low‑altitude photo, one can see forested areas in the lower right. The circular shape in the water near the top of the photo is a USACE contained disposal area that holds dredged materials from the Saginaw River, Michigan. The containment area keeps dredge materials out of the aquatic environment and creates bird habitat in the bay.

FIGURE 5.10  This aerial photo was taken from a commercial aircraft flying over the Midwestern United States. Note the large size of the area where river meandering has occurred. The extreme variability in land shapes, the disorganized drainage pattern, and the lack of human‑induced features such as roads all provide strong evidence that this is a hydro‑ logically shaped landscape.

Additional Methods and Considerations

67

FIGURE 5.11  This is a low‑altitude image taken over farm fields and forested wetlands in Van Wert County, Ohio. The scene appears from one perspective in this image and a different one in Figure 5.12.

War II and continuing on a periodic basis to the present (Lyon 1987; Garofalo 2003). Often more than ten individual dates of aerial photos or images can be identified for a given site. This photo record can be exploited whenever the historical condition of a site needs to be evaluated (Lyon 1987, 2001). They are also useful in judging change in conditions over time (Lyon et al. 1986; Garofalo 2003) or for making an assessment of the original conditions of wetlands (Figure 5.12). From a regulatory viewpoint, the original condition and subsequent illegal fill‑ ing of a wetland can be documented from photos or images. Most USACE Districts make frequent use of historical and current photographs of wetland areas (USACE 2010a–f). Filled areas look very different from undisturbed wetlands, due to the dif‑ ference in reflectance of dry soil (relatively light toned) and wetland (relatively dark toned). Simple comparisons of current and historical photographs allow rapid iden‑ tification of filled areas. Subsequent evaluation of permit files and/or field inspection can verify the character of the fill. An additional advantage that aerial photos or satellite images offer is the capabil‑ ity to make precise and accurate measurements using principles of surveying and photogrammetry. From a few survey measurements on the ground or distance mea‑ surements from maps and measurements from aerial photos of the same distance, one can calculate horizontal distances and vertical elevations of selected features (Falkner 1994; Falkner and Morgan 2001). Almost all topographic maps are made with these photogrammetric and surveying technologies, and, hence, one can develop topographic mapping products from photos and use the variables of distance and of elevation to help in identifying and delineating wetlands (Figure 5.14).

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FIGURE 5.12  The same area of Figure 5.11 is shown here from a different angle. Comparing multiple images from a low‑altitude platform can provide a better overview of conditions on the ground. Is the forested area an upland or wetland forest or a mix? Note the bare soil as an irregular white‑toned area near the head of the forest where crops have not been established. Could the area have been wet during planting?

FIGURE 5.13  The white stripes in this field in Van Wert County, Ohio, are field drainage tiles or tubing. The tiles or tubing themselves are not visible. What creates the lighter stripes is lower water content in the soils. Drier soil typically appears lighter in aerial photos. In the field along the left side of the image the undrained soils are much darker. One can use aerial photos to locate drains, identify areas for repair, or find areas that need additional drainage.

Additional Methods and Considerations

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FIGURE 5.14  Look at the dark‑toned soil patch along the left reaching toward the center of this image. Note the relatively uniform dark tone and irregular shape. This area may have been a wetland area in years past and developed relatively high‑organic‑content soils that retained the dark‑toned organic matter and absorb moisture.

The identification of potential wetlands at the routine or intermediate level can be difficult during some times of the year. This is due to inclement weather includ‑ ing snowfall, cold and hot temperatures, or some inherent problems such as size of the properties, presence of hazardous materials, limits to access of lands, and/or possible disturbance of plants or animals. Other considerations are the risk to field personnel from noxious plants and potentially dangerous wildlife or insects. Photos can be used under these conditions to allow “access” to the site (Figure 5.15). They may also augment other measurements and allow some work to progress under less than desirable conditions.

FIGURE 5.15  Dark tones show moist soils across the bottom of the image adjacent to forest cover. Farmed areas drain to these moist soils through channel ways.

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One can use aerial photos or images to evaluate wetland characteristics over time (Lyon and Olson 1983; Lyon and Drobney 1984; Lyon et al. 1986; Williams and Lyon 1991; Lyon and Greene 1992) and do so during the course of the senescent or dormant seasons. Many groups make use of aerial photographs or images to identify and quantify potential wetlands year‑round and avoid poor conditions for fieldwork (Figure 5.16). For USACE permitting purposes, it may still be necessary to await the growing season to complete the analyses and present the results for inspection. There are numerous advantages in employing analyses or interpretations of pho‑ tos or images as one of the many data sources in an integrated wetland analysis. In the process of identifying wetlands it is desirable to determine what type of wetlands are present. Using aerial photos or images it is possible to separate the wetlands as to type, such as forested wetlands (Figure 5.17), marshes, and/or riparian areas. Using aerial photographs or images, wetlands can be labeled or categorized as to types according to a given classification or categorization scheme. Classification schemes or systems are useful in many activities including delineation. In particular, scien‑ tists and engineers favor the USGS Anderson system (Anderson et al. 1976) or the

FIGURE 5.16  Between the darker uplands and the open pond waters, there is a mixture of light‑toned soil areas and darker‑toned wetland plants. These are shallow emergent wetlands.

Additional Methods and Considerations

71

FIGURE 5.17  This low‑altitude image shows an overview of land features. The combina‑ tion of tone, texture, pattern, and adjacency helps delineators identify features such as forest cover in farmed fields or wetlands bordering creek areas. Higher‑altitude images are not as useful for this broad identification.

National Wetlands Inventory System (Cowardin et al. 1979) for describing wetlands as to type when mapping over regional and national scales (Figure 5.18). Often individual states have optimized the Anderson system for local conditions, and this state‑driven categorization of wetlands usually has a similar goal and meth‑ odological approach to that used in the U.S. Fish and Wildlife Service’s (USFWS) NWI Program and other state or federal agency programs.

FIGURE 5.18  Note the uniform rectangular farm fields in northwestern Ohio. In the United States, the Land Survey system parceled land into uniform sections with roads running along the boundaries. Departures from this regular pattern are there for a reason. Streams and adjacent forests that have resisted farming are ever present. Could it be that they are too wet to work?

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FIGURE 5.19  In agricultural areas, lands that do not readily support farming are often used for homes, farm buildings, and cemeteries. Forested areas and wetlands are often adjacent to these domestic areas.

In these efforts, wetlands are identified by the interpreter from aerial photographs or images and the wetland boundaries are plotted. The type of wetland is then described according to the types listed in the applicable classification system such as a state‑developed system (Figure  5.19). Often they are also described with the NWI wetland classification system to facilitate comparisons and communications of results (Cowardin et al. 1979). One can acquire aerial photos or images by custom order or contract through a vendor. Or one may make use of a variety of times and types of aerial photographs or images from governmental and private archive (Lyon 1987). Archival photos will be of both historical and recent origin. It is desirable to obtain and use a variety of photos from the archive (Figure 5.20). This is because one can accumulate histori‑ cal data on wetlands and other conditions related to soil, hydrology, and vegetation conditions. One can also document the chronology of land use activities and do so with an independent source of information. To map wetlands from aerial photos or images, it is desirable to have an opera‑ tional definition to facilitate this work. General wetlands or potential jurisdic‑ tional wetlands have been defined (Lyon 1993, 2001) as having one or two or three of the wetland indicator criterion as described by the USACE (1987). This operational definition allows one to create mapping products that are useful as per having a definition that fits the capabilities of the aerial or remote sensing tool. Aerial photographs are acquired at different times and record a number of wet‑ land conditions. These include hydrological conditions, as well as the extent and type of wetlands present. Use of classification schemes and aerial photographic or image interpretation of wetlands provides a means to map general types of wetlands and a product to be used to determine the area of the wetland. Also, photos or images are

Additional Methods and Considerations

73

FIGURE 5.20  Even in areas of limited habitat availability, plants persist. The vertical view shows some habitat interspersed with roads, ponds, and farm fields.

acquired with parts of the electromagnetic spectrum beyond the human eye, such as the near infrared. These images supply additional information (Figure 5.21). It is important to consider the time of year when the particular archival photos or images were taken and prevailing conditions of plants, soils, and hydrology at that particular time. If one accesses a variety of archival photographs or images, it is also possible to evaluate wetland conditions during leaf‑off and leaf‑on periods of the year. Thus, seasonal change can be inferred from multiple date coverage of wetland areas. One needs to interpret the aerial photographs or images with knowledge of the seasonal condition of plants. This knowledge of condition is often referred to as the growth cycle, seasonality, phenology, or the crop calendar of the plants. There are certain common elements of plant “behavior” or growth cycle, such as death or senescence. Senescence or “fall colors” occurs when the chlorophyll and its green reflectance characteristics disappear with the breakdown of the chlo‑ rophyll. One sees the reflectance of other plant pigments that remain. These other pigments include anthocyanins, flavonoids, and other constituents. These pigments are plant wastes stored in vacuoles or waste‑holding voids within the plant cells.

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FIGURE 5.21  Using alternative types of film can be helpful in some cases. Here, film that is sensitive to the near infrared shows water as very dark toned. Plant‑laden areas appear as very light toned. The presence of homes, farm buildings, agricultural lands, and highways can conceal wetland habitats from the ground view but are revealed from the vertical.

These compounds give deciduous foliage its yellow, orange, and red colors in the fall season and provide the orange color of dead evergreen needles. Senescence is a common characteristic of seasonal plants, and it is a common element in the behavior of all plants. One can also observe genus and species dif‑ ferences in the growth cycle, including differences in the timing of reproduction or flowering, plant shape or structure, rates of growth, timing of the onset of senes‑ cence, and differences in location where a plant grows or its habitat (Figure 5.22). Many of these plant characteristics can be interpreted and recorded from aerial pho‑ tographs or images. Sources of these photos or images include the U.S. Geological Survey (USGS), the U.S. Department of Agriculture (USDA) and related agencies, the National Oceanic and Atmospheric Administration (NOAA), the U.S. Environmental Protection

Additional Methods and Considerations

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FIGURE 5.22  Aerial images from archives are a great way to capture details and track changes over time. Here, the location is the Black River entering Lake Michigan.

Agency (USEPA), the National Archives and Records Service (NARS), as well as the archives of mapping companies (Lyon 1987; Lyon and Greene 1992; Ward and Trimble 2007). These groups maintain coverage over portions of the United States and can be counted on to supply multiple dates of coverage of a given area. Photos or images are also available from local archives, and these may be maintained by a variety of groups. In each county seat of government, aerial pho‑ tos of recent or older “vintage” are held by the county offices of USDA–Natural Resource Conservation Service (NRCS, http://www.nrcs.usda.gov/) and/or the Farm Service Agency (FSA). These are the same offices that supply the county soil surveys and support crop programs on a local basis. In the county offices, the photos may be viewed and assistance can be provided in ordering them from archives. These photos are also valuable because they are taken during the grow‑ ing season in support of crop programs. Most archival images have been collected in the leaf‑off seasons so that the contour of the land can be seen through dormant plant canopies. Hence, these FSA/USDA images are very valuable for interpreta‑ tions of growing season features.

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In most state capitols and in regional headquarters, photos or images may also be available. In particular, one should try to access archives maintained by state depart‑ ments of transportation (DOT), departments of natural resources (DNR), depart‑ ments of environmental protection, departments of ecology or wildlife, and/or other state agencies with similar mandates. In particular, state DOT photographs are valuable because they are flown at low altitude and they are large in scale and objects on the Earth’s surface appear large to the eye (Figure 5.23). These products supply very good detail for local wetland area evaluations and evaluations of river and stream characteristics and drainage pat‑ terns important to understanding hydrology conditions and helping to fix jurisdiction based on water resource characteristics. Contract photography missions to acquire “custom” photos can be flown by a vari‑ ety of groups (Figure 5.24). Commercial mapping firms can be employed and these regional and national firms can be located in Web or other directories. Many of these firms can also be identified from the list of sustaining members of the American Society for Photogrammetry and Remote Sensing (ASPRS). This list is available from the Society* or from its journal Photogrammetric Engineering and Remote Sensing. This journal is archived in most libraries or is available from ASPRS or their Web site. As described earlier, most large‑scale topographic maps are compiled from aerial photos. These photos can be obtained from the company charged with mapping the site for engineering design purposes. The scale of photos should be large, and hence

FIGURE 5.23  Extractive industries often remove great quantities of materials yet provide opportunities for wetlands to develop in the waters that pond in pits. Eventually many such sites will develop wetlands. Though difficult to view from the ground, these resources can be identified from aerial coverage. *

5410 Grosvenor Lane, Bethesda, MD 20814.

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77

FIGURE 5.24  A custom aerial image shows the parallel drainage pattern formed downslope on the syncline–anticline complex of folded Earth.

they will provide additional detail (USACE 1993; Falkner 1994; Lyon et al. 1995; Falkner and Morgan 2001). One can also take advantage of the capabilities of color and color infrared (CIR) types of films. Often these films reveal more information about plant and water resources than do black‑and‑white photos alone. Portions of the spectrum that humans may not see, such as the infrared, can be recorded with special film emul‑ sions or instruments. Color or color infrared photos are available from archive, by contract with an aerial mapping firm, or photos may be taken by other means (Lyon 1987; A. Ward and Trimble 2005). Several characteristics of wetlands can be used to identify and quantify their pres‑ ence from aerial photos or images. CIR photos or images are particularly suitable for identification of wetland areas, because they can help distinguish plant species or plant communities depending on scale. One can also identify water resource characteristics using CIR. A valuable application is locating the water surface edge. This can be accomplished by taking advantage of the very high absorption characteristic of infrared light by water and the contrasting very high reflectance of soil and vegetation. Reflectance of light is defined as the ratio of the incoming radiation to the exiting radiation, and it is char‑ acteristic of a given material or mixture of materials. Reflectance is also known as the tone we see on aerial photographs, and reflectance is probably the most impor‑ tant clue in identify features on the Earth’s surface (Lyon et al. 1992; Lyon 2001). Experience has demonstrated that several wetland plant communities or types can be identified from CIR using photo interpretation “clues.” These types include emer‑ gent wetlands, submerged or submergent wetlands, forested wetlands, and shrub/ scrub wetlands. The clues that can be used to identify these wetland communities are described as follows.

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FIGURE 5.25  One advantage to using low‑altitude images is that they can be collected at any time of year.

Emergent wetlands communities are variable in plant species composition and juxtaposition of plants, water and soil, and as a result will be variable in color or tone on infrared photos or images. This variability in color or tone is distinct from the uniform color associated with other plant communities such as one-species stands of trees or farmed fields (Figure 5.25). Sometimes, one encounters uniform tone or color when a single species is predom‑ inately present in a vegetation community. On the eastern and western marine coast, Spartina are found in “monotypic” stands, and these wetlands are usually uniform in color or tone. In areas of cattail stands, one will encounter somewhat uniform color or tone, but these clues may be broken up by the clonal growth pattern or “bunch‑like” groupings of cattails. The bunches are created by vegetative reproduction from exist‑ ing plant material, as opposed to the seed or sexual methods of reproduction. Emergent wetlands can be identified by a number of photo or image interpretive clues. For example, their proximity to the terrestrial/aquatic interphase can be a clue to their presence. Also, the presence of streams entering and/or exiting the site is a good clue. The red or magenta color on CIR is indicative of growing plants. One can note their irregular boundaries, in contrast to human‑created boundaries such as the regu‑ lar pattern of property lines that follow the U.S. Land Survey. During the non‑growing season, emergent wetland areas appear very dark in color or tone. This is because the plants are devoid of chlorophyll and hence the character‑ istic reflectance of green plants as shown by a red color on CIR film is absent. The presence of water also makes the reflectance of emergents or their residue even lower than surrounding terrestrial plant and soil materials. The combination of chlorophyll‑free plant residue and presence of water creates this very low reflectance or dark color/tone condition in dormant emergent wetlands as compared to surrounding areas. This characteristic reflectance can be used to reli‑ ably identify wetland areas on aerial photos (Figure 5.26).

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FIGURE 5.26  Note the adjacency of salt deposits, abandoned river channels, and upland areas in this image.

Submerged wetland communities are found beneath the surface of the water and hence are called submerged plants or submergents. They appear characteristically dark in color or tone. This is due to the inherent low reflectance of water that covers the plants. The dark color or tone is also due to the general low reflectance of plants in the visible portion of the spectrum. Most infrared light is extinguished by water and hence the infrared reflectance of plants beneath the surface of water is very low to zero, and there is no infrared contribution or red color found on CIR photos or images of submerged wetlands. These phenomena create the very low reflectance, color, or tone of submergent wetlands. They are some of the darkest features on aerial photos, and they can be identified by the characteristic dark color or tone and irregular shape. This is in com‑ parison to sand and clay bottom sediments, which have higher relative reflectances (Lyon 1980, 2001; Lyon and Olson 1983; Lyon et al. 1992). They are commonly found in shallow water where the high reflectance or bright tone of bottom sediments is apparent from the air and provide a stark contrast between the dark‑toned plants and light‑toned sediments and irregular shape of plant community boundaries. Shrub‑scrub wetland areas exhibit wetland soils and hydrology but differ from the other wetland types mentioned here in that they are populated largely by shrubs, bushes, or brush. These woody plants are persistent year to year. These areas can be identified by the interpretation of their characteristics on photos or images. Clues include the rough texture or fine‑scale variability in the photo or image color or tone resulting from the shape of the shrub branching pattern and the shape of the tops or crowns of shrubs. The irregular shape of the wetland area and the presence of water or streams running into and out of irregular‑shaped areas are also good clues. The association of the shrub wetland with adjacent emergent or forested wetlands is an additional valuable clue. Forested wetlands are commonly known as swamps and are defined by the pres‑ ence of trees that mostly cover the site and are persistent. Forested wetlands may

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be identified on CIR films by the red or magenta color of green leaf material in the growing season and by the texture, or “roughness,” of the tone or color resulting from the spatial variability of tree canopies or crowns. On black‑and‑white photographs or images, forests exhibit the same textural characteristics but are dark toned due to the low reflectance of woody plants in the visible portion of the spectrum (Lyon and Olson 1983; Lyon 2001). Other good photo interpretation clues include the irregularly shaped boundaries of the forested area, the presence of standing water on the ground surface, or a stream entering or leaving the area. The lower relative topography compared to the general topography of the surrounding areas is an additional valuable clue (Figures 5.11 and 5.12). Forested wetland areas may be populated with trees that drop their foliage in winter (deciduous) or trees with year‑round green foliage (evergreens). Evergreen trees will display the characteristic red or magenta color on CIR film on a year‑round basis. Hence, CIR can help to identify evergreen forested wetlands and separate them from deciduous forested wetlands using the contrasting colors or tones of pho‑ tos from the summer or leaves‑on period and winter or leaves‑off period. Forested wetlands may be difficult to identify with leaves‑on photographs. Most CIR photos or images are taken during the growing season, and often the forest canopy obscures the wet ground below. At the height of the growing season, upland trees and wetland trees may be difficult to distinguish based on plant reflectance alone (Lunetta et al. 1999; Lyon 2001). Hence, it is desirable to obtain additional leaves‑off archival photography or images to help identify forested wetlands from upland forests. Most existing archi‑ val black‑and‑white photographs were acquired during leaves‑off conditions, so that ground contours could be mapped without being obscured by foliage. Use of a com‑ bination of photos from different times is always a useful approach, but it is particu‑ larly so in the case of separating forested wetlands from upland forests.

AERIAL PHOTOS OR IMAGES FOR CHARACTERIZING SOILS Aerial photos and remote sensor data can be useful for identification of wetland soil areas. It is possible to determine general moisture conditions of soils by color or grey tone of photos. Differences in color or tone may be reliably interpreted for variation in the relative hydrological and textural characteristics of soils (Lyon 1987). Wetter areas of soils appear as black or dark tones on black‑and‑white aerial photographs or images. Wet soils are always darker than the same dry soil. This is because water greatly reduces the reflectance of materials it coats or mixes with and brings its low reflectance characteristics to the mixture. This phenomenon can be used as an indicator of relative soil moisture from aerial photographs. These dark tones can also be used as indicators of relatively low topographical areas, which may commonly be filled with surface or subsurface water, and they function hydrologically as conduits of runoff (Lyon 1987; 2001). Fine‑textured soils composed mostly of silts and clays can also be identified by evaluation of photo tone. These soils are usually medium grey to dark grey in tone. These soils may be found on lower elevation parts of fields or other areas where water ponds.

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Coarse‑textured soils appear as lighter grey tones on black‑and‑white aerial pho‑ tographs or images. This results from the relatively rapid drainage of rainfall by the coarse textured soils. Identification of lighter tones in soils may indicate the location of coarse‑textured soil deposits in abandoned stream channels adjacent to existing streams and rivers (Lyon 1987). These abandoned channels may be possible paths of movement of subsurface flow.

LARGE AREA WETLAND EVALUATIONS Aerial photos or images are particularly useful in evaluations of potential wetland resources over large areas. An effort might involve areas in size from 2,000 acres to an entire state. Naturally, this sort of activity would be of interest to a variety of users. It can assist the regulatory process in general by providing additional informa‑ tion of a uniform quality and content. A similar process is performed by the NWI of the U.S. Fish and Wildlife Service to provide NWI wetland maps of selected regions (Cowardin et al. 1979), and these products will help meet the need for generalized wetland information over large study areas. It is important to note that one should attempt to identify only potential jurisdic‑ tional wetlands using a large area evaluation. This sort of a project may be directed to identify areas that are jurisdictional wetlands, but the approach is much more successful when one attempts to evaluate what is called potential jurisdictional wet‑ lands or general wetlands (Lyon 1993; Lyon 2001). To make a true determination of a jurisdictional wetland it is necessary to test for the three criteria and to do so with fieldwork. To identify resources in a large area it is best to use a combination of maps and custom order aerial photos and archival aerial photos or images. The photographs or images may satisfy many needs, because they will be both historical and of recent origin. It is desirable to fly custom photos or obtain fine resolution satellite images, and to use a variety of available photos or images from archives (Figure 5.27). This is because one can accumulate historical data on wetlands during different times, during different meteorological and hydrological conditions, and during leaves‑off and leaves‑on conditions. One can also take advantage of the fact that archival aerial photographs or images often include different film or image types that may reveal more information than black‑and‑white photos or images alone. These color or CIR archival photos or images can be acquired for little cost, yet they can potentially supply a very useful “data point” on plants, soils, and hydrology. The steps in aerial photo or image analysis of wetlands over a large area include the following:

1. Fly aerial photo or digital image coverage of the region or county at relative large‑scale in Fall and/or Spring seasons. This will allow evaluations during two different soil moisture and plant growth conditions and record current land cover or use of the area. Black‑and‑white or color film or digital cameras can be used during leaves‑off conditions. CIR film or digital coverage can be

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FIGURE 5.27  Low‑altitude images from a small aircraft give a good overview of a site. Here a tank farm, storage areas, a pond, and the surrounding berm can be seen easily. Low‑altitude images are also useful tools for training others about the features in the landscape. This view helps train the eyes and mind to interpret higher altitude imagery where the individual ele‑ ments are less clear for interpretation.







used during leaves‑on conditions, and one can exploit the special detail that CIR provides and for evaluation of plant species and hydrological conditions. 2. Obtain available archival aerial photographs or images from a number of sources. To obtain the most complete record and to insure aerial photo or images coverage that addresses all three wetland criteria, it is important to write, phone, Web search or visit (1) the local USDA‑NRCS or Farm Service Agency offices, (2) state resource agency offices, (3) state trans‑ portation agency offices, (4) the USGS EROS Data Center archive, (5) the USDA‑FSA‑Salt Lake City archive, and (6) the National Archives and Record Service. Included in the search would be archives of aerial mapping firms and any other archives that come to your attention during the search. 3. Take all the photographs or images, the county soil survey, topographic maps, and any other pertinent data sources and study them to identify and delineate potential jurisdictional or general wetlands (Lyon 1993; Lyon 2001). 4. If custom aerial photos are flown during the growing season, these photos or images and additional examples from archives should be used to further locate individual wetland areas. 5. Use the information developed from evaluations and interpretations, along with any field experience, to integrate these data sources. Sources such as maps of geology, watersheds, and drainage can help identify potential areas of wetlands in a large area inventory.

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6. Use fieldwork to check the adequacy and accuracy of mapped wetland areas. Make corrections as needed, such that the product shows the highest probability areas of potential jurisdictional wetlands. If possible, develop a method to assess the accuracy of these mapping products and the wetland classes they display (Congalton and Green 1998, 2008; Lunetta and Lyon 2004). This is particularly important if the result‑ ing large area mapping product is to be used by a variety of groups or is to be used as some type of regulatory tool. 7. Take these map products and transfer boundaries to digital mapping prod‑ ucts using geographical information system (GIS) software or remote sens‑ ing analysis software, or other geospatial processing capabilities. In their absence, one can use acetate or Mylar or other permanent, transparent materials to facilitate production of mapping products. 8. Provide maps and other data products and a report summarizing the meth‑ ods of production and characteristics of the products and estimate their accuracy, if possible. 9. Allow a period for evaluation of the products by interested parties. 10. Incorporate comments and criticisms and any new information that has been identified. Produce the final products that identify and locate potential jurisdictional or general wetland areas.

It is also possible to utilize satellite or airborne and space‑borne sensors to inventory potential jurisdictional wetlands (Lyon 1979, 2001; Lyon et al. 1992, 1998). This satellite sensor-based approach is particularly appropriate when large areas are to be evaluated. Airborne or satellite sensor data are in a digital formats and the capabili‑ ties of computers and geospatial software processing techniques can be exploited. Remote sensors, much like CIR films, also measure light in different parts of the spectrum, which may provide more details on wetlands than are found in the visible part of the spectrum. Digital remote sensor data are particularly useful in modeling of habitat characteristics and ecological indicators (Lyon et al. 1987; Lyon 2001), and these modeling efforts have seen great results in addressing these difficult to measure characteristics and indicators. Recent work using radar or microwave sensor products has demonstrated value in wetland analyses. Microwaves are responsive to the structure of features and to the dielectric constant of the materials. Water in soils and standing water demonstrate distinct spectral differences in radar sensors compared to dry soils and the absence of standing water, flooding, or saturated soils. The use of radar products with visible and other spectral products in a data fusion exercise can be valuable in identifying wetland resources. Certain difficult‑to‑identify wetlands such as the separating of forested wetland from upland forests during the growing or leaves‑on season, wet‑ land and riparian resources under high canopy forests or jungles, and shrub‑scrub or rangeland wetlands from terrestrial rangeland shrubs land covers have demonstrated great utility or potential utility (Ramsey 1998). Laser microwave sensors or light detection and ranging (LIDAR) data have also proven valuable in data fusion exercises. LIDAR products can show subtle differ‑ ences in vegetation crown shapes and relative height as well as grown elevation and

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riparian or stream floodplain and stream boundary and watershed characteristics. With increasing availability of these products and use in data fusion efforts, one can help to identify potential jurisdictional wetlands or general wetlands from upland and riparian land covers. It is also possible to develop detailed watershed products and water drainage characteristics for small or relatively unmapped areas and supply greater detail for evaluations of water boundary conditions.

NATIONAL WETLAND INVENTORY PRODUCTS Decades ago, the USFWS generated the idea and developed the methods to con‑ duct an NWI. The goals were to provide maps of the extent of wetland areas and to identify these areas through the use of aerial photographs, photographic and image interpretation and photogrammetric technologies, and geospatial and GIS tools for analyses and display (Cowardin et al. 1979; Welch et al. 1992; Yi et al. 1994). The main product or “final step” product is a series of wetland maps products at small‑scale (1:100,000), intermediate‑ or moderate‑resolution scales (1:24,000), and in digital form for the United States for geospatial analyses (Williams and Lyon 1991, 1997). The mapping work was executed from aerial photographs and images at a variety of scales, and the photos and images generally ranged from 1:60,000 to 1:12,000. Maps of what would be called here potential jurisdictional wetlands or general wet‑ lands can be viewed as product and processed in computer mapping or geospatial analyses systems. Products can be viewed and distributed as computer files or maps or printed at an agreed‑upon scale, such as 1:24,000 scale, and can be used for analy‑ ses with references to the mapping guidelines provided on the paper maps or at the Web site (Wilen 1990; USFWS 2004). The program is continuing to supply updates to these maps for the entire United States and to maintain and facilitate the use of these products to support planning and management activities related to NEPA, and other federal mandates, and the wetland‑related interest of the public. A graphic displaying the 1:24,000 scale maps of the United States that are avail‑ able can be obtained from the National Wetland Inventory at http://www.fws.gov/ wetlands/. Web mapping services can be found at http://www.fws.gov/wetlands/Data/ WebMapServices.html. A number of services are available from nongovernmental vendors including Keyhole Mapping Language (KML) products and assistance from the OpenGIS Consortium. The wetland maps of 1:100,000 scale are of limited value due to their small scale. Wetlands that are large enough to engender regulatory attention may not show up on the 1:100,000 scale products but some will probably appear on 1:24,000 intermedi‑ ate‑scale products. These maps are useful in evaluating the stream and river drainage systems in the area of interest and can be informative in establishing general con‑ nectivity of water resources. In production of NWI products, the types of wetlands are labeled using a catego‑ rization system developed especially for the effort. The combination of locating and mapping wetland areas from one or more dates of photos or images and categorizing them as to type results in a product that is a thematic map of wetland land covers.

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Geology maps, soil survey maps, land use–land cover maps and other maps are all examples of maps that display themes and are thematic maps. Wetland types or themes are categorized and described using the National Wetland Inventory Classification System (Cowardin et al. 1979). The system is hierarchical in that it possesses tiers or layers of categories or types. It is possible to make wetland maps of varying degrees of detail by providing all the category labels or only a sub‑ set of the category labels. The basic level of identification involves five general categories or types of wet‑ land. The class names are similar to the hydrological conditions of the wetlands. The wetland types and their system labels or types include lacustrine or lake‑based wet‑ lands (L), riverine or wetlands found along rivers (R), palustrine or wetlands found inland from obvious water bodies (P), estuarine wetland types found where fresh‑ and saltwater systems mix in the coastal zone (E), and marine or saltwater wetland types found adjacent to or in saline waters (M). NWI map products have been generated for many years and are now selectively available for much of the United States. If a map is available for a given area, it may be useful as a guide to where potential jurisdictional wetlands are located and pro‑ vide information as to their identity or type. One should also note that NWI maps at either 1:100,000 or 1:24,000 scale are necessarily a “coarse look” at the issue and may include too many or too few areas that are true jurisdictional wetlands. The definition of jurisdictional wetlands and the wetland types used for the NWI are not the same. The NWI describes general types and locations and is on par with the detail and quality of a county soil survey. Hence, NWI products provide a good indicator of wetlands for the routine level of wetland evaluation. An NWI map should be used much like the USDA‑NRCS county soil survey products, in that they are an indicator of potential jurisdictional wetlands. The NWI maps were not intended to be a regulatory tool. They certainly may be used by a variety of groups including the USACE to identify properties that may need a wetland assessment. Like county soil survey data, NWI maps will often help “trigger” an inquiry by the USACE upon development of a property.

SURVEYING AND MAPPING An important component of a delineation of jurisdictional wetlands is an estimate of total wetland area and a map of the location of the wetlands. This information and products may be developed by the wetland expert, if the person is also familiar with surveying, mapping, photogrammetry, GIS, and/or computer‑aided mapping methods (Lyon 1995). Regardless of background, the wetland expert must be capable of rendering an accurate and precise wetland boundary on the ground for inspec‑ tion and record that boundary on available maps for inclusion in resulting wetland reports (Figure 5.28). A general mapping capability is suitable for routine or reconnaissance‑level eval‑ uations. In cases where large wetland areas are encountered or small, very valu‑ able areas are identified, it may be necessary to obtain the assistance of surveyors.

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FIGURE 5.28  Survey monuments are created to record horizontal and vertical positions for reference. They can be useful in all types of work including that of wetlands. Pictured here is a U.S. Lake Survey monument placed in the Laurentian Great Lakes to help understand the natural vertical fluctuation of water levels that can range approximately 6 feet from lowest to highest recorded levels.

Surveyors can assist in placing the boundary of jurisdictional wetlands on a map and thereby facilitate the permitting and planning process. An additional advantage of surveying the boundaries of jurisdictional wetlands is that the acreage estimate is usually a more accurate and precise estimate than that of the wetland delineator alone. Usually, the surveyed estimate is smaller in acreage than the relatively crude estimate of the delineator. A more accurate and precise boundary is a better product for the landowner and the USACE and oftentimes the acreage estimate is smaller. This may be a vital consideration when the initial esti‑ mate of acreage exceeds one acre or some other critical quantity used in the permit‑ ting process. Obtaining a survey is usually a simple matter because civil engineers and survey‑ ors concerned with the design of the site plan are in possession of requisite knowl‑ edge and equipment to complete the mapping task. The services of surveyors can be made available to permanently record the wetland boundary delineated by the expert. The boundary/topographic mapping data used in the engineering site plan can be employed as a base map and the wetland boundary placed as an overlay on the map using surveying, mapping, or computer‑aided design software. The location of wetlands must be “flagged” in the field for the survey crews by personnel familiar with the extent of jurisdictional wetlands on site. It is desirable to have the wetland expert delineate the boundary and flag it and have surveying personnel measure the area and map the boundary on the available site maps or maps they create from the survey. It is also desirable to have the wetland expert accompany the surveyors to the site and familiarize them with the wetland boundar‑ ies and method of flagging. Upon completion of the survey and the resulting wetland map, an estimate of wetland acreage can be made by surveyors and supplied to the delineator for use in the wetland report. This survey and survey map product are

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also valuable documentation of the site that may be useful if post‑construction and post‑permitting activities should call the work into question. To provide an optimum survey of wetland boundaries for the purposes of permit‑ ting and to provide suitable detail for maps at scales of one inch = 50 feet to 1 inch = 200 feet, it is necessary to be respectful of scale considerations in flagging and surveying the boundary. To obtain a good product, it is important for the wetland field personnel to overly flag the boundaries. It is also important to select a “line of sight” that is straight for distances of, say, 5 to 10 feet or more. An optimal amount would be 50 or more feet, though the variability in wetland shape may not allow this. The distance of 20 to 50 feet on the ground equates to a distance of 0.04 feet or 0.5 inches on a map of scale 1 inch = 100 feet. Hence, it serves a practical purpose to flag a boundary for the survey that includes relatively long, straight distances. It is also important that the surveyed and flagged boundary remain a true representation of the boundary of jurisdictional wetlands. In the field, the wetland expert or other knowledgeable person can use a line of sight or hand compass to help line up the flags and create straight boundary lines (Lyon 1995). The wetland personnel may also wish to pace these distances and record their angles using a compass. These data can be used to (1) make a map for a wetlands report or (2) provide a preliminary map and assist personnel in completing a more detailed survey. The existence of high-frequency flagging and a general map will greatly facilitate the work of the surveyors and insure an accurate and precise boundary.* It may also be desirable for the wetland expert to accompany the surveyors and assure the quality and resolve any boundary ambiguities on the spot. In the case of a lawsuit, this supervision of the survey would be vital as it relates to process and perhaps to chain of custody. This approach assures a high‑quality mapping product and an accurate and pre‑ cise estimate of wetland area. This is a particularly important detail, because a well‑defined and mapped boundary is generally a correct estimate and produces the best result for the USACE. Such a map, particularly of large wetland areas, is also greatly appreciated by government regulators.

*

Note that the use of global positioning systems (GPS) allows a number of navigation activities to be facilitated. Over short distances, the GPS may not be as valuable as, say, a survey or use of traditional methods.

6

Advanced Methods, Hydrology, Soils, and Plants

Most delineations can be performed with the techniques and methods described in earlier chapters. When complication seeps in, more and varied approaches become necessary. Here, a variety of advanced tools and ideas are supplied to help in harder applications. These approaches are described in general, and very specific guidance can be obtained through the use of the literature, Web sites, and practice (Figure 6.1).

QUALITATIVE METHODS The wetland delineation process and techniques were designed to do assessments in the field and document the results. The goal is to agree upon a boundary by the regulators and the landowner. It may be necessary to do more to reach consensus. The approach does not contemplate heroic efforts unless they are necessary. For example, having an engineering firm do multiple seasonal hydrologic moni‑ toring is only necessary or desirable if there is a clear need or lack of agreement between landowner and regulators. A detailed, multiple‑year study of areas from aerial photographs or remote sensor images is only necessary or desirable if agree‑ ment cannot be reached on permitting. Hence, these tools are applied where needed and to foment consensus (Figure 6.2).

Regional and Local Guidance The practice of evaluation of wetlands as to their presence and extent has stretched throughout the nation. Due to the diversity of ecological and environmental condi‑ tions, there has been a large effort to develop methods, procedures, and tools to address these myriad conditions. This approach may have been advanced in the name of making uniform the appli‑ cation of rules and statues or by efforts to solidify the procedures and the adjudica‑ tion of wetlands. Regardless, much work has been done, and the efforts may be valuable for addressing these diverse conditions and locations (Figure 6.3). These methods (see U.S. Army Corp of Engineers [USACE] publications in the References) also can be useful as a reservoir of techniques to inform a given appli‑ cation because they have been established and tested. They can be helpful in char‑ acterizing a given site that is typical of local conditions but does not fit the average 89

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FIGURE 6.1  This is a classic wetland look. An expanse of open water is surrounded by stands of vegetation and trees for nesting and perching.

FIGURE 6.2  Sometimes wetlands are inconveniently located next to roads or other con‑ structed features. Though less picturesque than the previous photo, these wetlands are every bit as functional.

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FIGURE 6.3  A real conundrum is the presence of reed grass in wetland and upland areas. Though perceived by the public as an attractive plant, it is lower in habitat value than indig‑ enous species.

situation throughout the nation. Or they may be useful when an unusual set of condi‑ tions is present or disturbance has rendered necessary characteristics absent.

Hydrology A great deal has been written about hydrology and how hydrological conditions can create and maintain wetlands. For the purposes of permitting, it is important to establish the characteristics of an area to determine whether it has met the hydrologi‑ cal criterion of the wetlands definition. To an extent, the great volumes of hydrological knowledge are a help to under‑ standing the existence and the important functions of wetlands. One has to balance needs for identifying wetland hydrology in the field using qualitative methods versus the requirements of the definition and regulatory practices either locally, regionally, or nationally. These characteristics also become important when the hydrology of a wetland is difficult to determine due to exceptional or atypical circumstances. These conditions can result from an unusual hydro period or seasonal deviations from usual conditions in rainfall, snowfall, or intensity and duration of each. They may also differ due to the creation of drainage near or on the site or by the alteration of the drainage condi‑ tions of the wetland in some other manner such as earthmoving. Or the regulatory agency may require additional information beyond the field‑expedient measures usually used in permitting activities (Figure 6.4).

QUANTITATIVE METHODS These methods and techniques have been worked out by a variety of practitioners. The USACE has been particularly active with studies by their headquarters and field units and in their research programs and laboratories. For example, you may wish to examine USACE examples (USACE 1988, 1995a, 1995b, 2005, 2006a–b, 2007,

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FIGURE 6.4  Specialized equipment is useful for monitoring hydrologic characteristics. A water‑level gauge and recorder can provide details in open water areas as well as in stilling wells or large pipe deployments.

2008a–e, 2009a–b, 2010a–f) or other pertinent efforts from your region for ideas. A great deal of the work is cited here, because it represents an organized effort and a resulting body of publications. And thus becomes a great source of alternatives that is uniform and stems from the “parent group” involved in regulatory activities; that is, the USACE. It is important to note that techniques have been developed for plant and soil issues as well as for hydrological issues (Figure 6.5). These efforts include methods and techniques that may be used to address poten‑ tial wetland areas found in dry or seemingly dry areas. The potential jurisdictional

FIGURE 6.5  Tidal action is one of those factors that virtually mandates the use of advanced methods for accurately delineating wetland boundaries. This large site north of San Diego, California, is a good example of a wetland subjected to tides.

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FIGURE 6.6  Mudflat areas are often overlooked as wetlands. Note the dark‑toned areas of submergent vegetation against the relatively light‑toned mud.

wetlands can include such examples as ephemeral wetlands, interdunal wetlands, wet‑ lands present in very sandy or well-drained soils, and deserts or other arid areas. Conversely, wetlands are found in very cold and wet areas, where the entire land‑ scape appears to be a wetland to the untrained eye. Though these areas appear wet to the lay viewer, they may experience low relative rainfall and cryospheric conditions such as frozen Earth or permafrost and effectively “pond” water and occasion the presence of wetland‑loving plant types and appear as wetlands. Alpine and moun‑ tainous areas can be like this, as well as taiga, tundra, and arctic areas. It is possible to argue that too much emphasis has been placed on characterizing problematic situations, in what might be an attempt to be uniform in application of regulations in the face of the great diversity that composes the nation (Figure 6.6). As one reviews the titles of publications and thinks of the work that has been incorporated into these efforts, the “one‑size‑fits‑all” approach comes to mind. Yet these efforts can be a great source of guidance in application of techniques to a given site, and they supply approved or somewhat approved tools from the regulatory entity.

Hydrology Measures The issue of hydrology of wetlands is an important example, because hydrology drives the presence of wetland conditions, including anaerobic soil chemistry, and occasions the presence of wetland‑loving plants (Figure 6.7). The purpose of hydrology indicators is to provide evidence that the site has a current wetland hydrologic regime. These have been discussed in earlier chapters. However, when there is a need for more detail or the indicators are missing for per‑ haps other than natural reasons, there exists additional guidance and additional mea‑ sures that can help clarify wetland hydrology and document the presence or absence in recent times (Figure 6.8).

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FIGURE 6.7  A quick glance at this photo shows dark trees in the background. Logically, it would follow that other dark‑toned areas would also be vegetation. Soils and sand are light toned. The standing water in the center of the photo is grey. Note how water extinguishes light. This illustrates the differential reflectance and absorbance characteristics of materials.

The list of indicators includes recorded gauge data and historical records, visual observation of inundation, visual observation of soil saturation, watermarks, drift lines, sediment deposits, drainage patterns and rainfall, runoff, water level, and river stage (USACE 2009a–b, 2010a–f). In fact, a very authoritative study has been done on indi‑ cators and provides a nice tutorial and reference as to these topics (Skaggs et al. 1994). In the case of hydrology issues, conditions can differ based on the various contri‑ butions to the hydrological cycle, These can include precipitation and its variability or intensity, snowfall and snow pack, drainage, groundwater or surface water con‑ tributions, percolation and infiltration, and any changes that may occur due to natu‑ ral or human‑induced forcing functions (Ward and Elliott 1995; Ward and Trimble 2003). The use of methods that better characterize “average” conditions will go to the quality of the evaluation of wetland functions and wetland presence and extent.

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FIGURE 6.8  The public loves the look of cattails in a marsh, yet they provide less valuable habitat than other wetland plants for wildlife.

To better characterize these conditions one may use methods and techniques including extensive or more frequent fieldwork, monitoring or measurements, and multiple seasonal evaluations or year‑round or multiple‑year evaluations (Figure 6.9).

Wetland Hydrology Assessments It is always important to carefully examine and utilize definitions that encom‑ pass regulations. This is what the regulatory agencies and their staff do and ultimately how adjudications are made. Hence, it is invaluable to revisit these definitions and always keep them in mind throughout the process, because they will become the “test” that is applied to these activities and to the property under study (Figure 6.10). The definition of wetland hydrology can take several forms (see earlier chapters). The thrust of the definition is that hydrological conditions must be persistent enough during growing conditions such that soils are anaerobic and that soil conditions are such that plants that can tolerate or grow and procreate under these stressful condi‑ tions are found there and are abundant and dominant.

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FIGURE 6.9  With time one can pick out potential wetlands across the desert landscape. The green plants are often darker toned than the relatively drier upland species. Note the lateral line of dark foliage behind the cottonwood copse.

FIGURE 6.10  The riverine areas of Zion National Park in Utah show how obvious water resources and plants are not wetlands.

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Hydrology Details Field methods exclude longer‑term hydrological considerations such as average rain‑ fall and water table records. Examinations in the field on a given date necessarily can occur during above‑average rainfall months or below‑average rainfall months. Hence, it is valuable to consider the rainfall conditions of the past seasons and year when making hydrologic assessments under prevailing conditions that depart from average conditions. Naturally, rainfall and other hydrological considerations such as the conditions of drought can make qualitative, field‑expedient methods problematic. In the past, dis‑ tricts have issued guidance to help the evaluation of wetland hydrology. An example is the Norfolk District and the drought period of approximately 2007. Here they choose to inform and guide and to use more complex methods to make clear guid‑ ance during departures from average conditions such that the permitting activities could go on (Figure 6.11). Over the longer‑term assessments, varying results can be encountered. It is valu‑ able to consider a variety of records including rainfall and water table records. For example, the Norfolk District found that results from the examination of the field method showed that by only considering water table records from average rainfall months, many sites that did have wetland hydrology were incorrectly identified as uplands. They also found that sites that meet the hydrologic criterion under actual rainfall often do not meet the criterion when only months of average rainfall record are examined (Figure 6.12).

FIGURE 6.11  Riverine wetlands and riverine systems can vary in function and type based on flows that are variable themselves. Riverine wetlands near the Ohio State University cam‑ pus are a good example of this variability.

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FIGURE 6.12  Dry river beds (sometimes called washes) are always a challenge in arid regions. Advanced delineation techniques will help separate riverine areas from wetlands.

Results indicated that a site that satisfies the wetland hydrologic criterion on a long‑term average may be much drier than a site meeting the criterion under average rainfall conditions. These are examples where field‑expedient methods and results can be called into question by regulators based on hydrological conditions that may deviate from average conditions. Hence, one needs to use these data in harmony with other sources. One can be the antecedent rainfall monitoring data. This is because it influences the availability of water and the variability compared to the average conditions during and before the growing season period. This all goes to the USACE Manual definition that addresses the “average conditions” (USACE 2005). These advanced methods have been suggested or required in the past when unusual precipitation conditions prevail (Figure  6.13). A further example is the approximately 2006–2007 period in Virginia, where the Norfolk District of USACE issued an interpretation of hydrological measures. The Norfolk District Regulatory Office reviewed precipitation data from 2008–2009 with an emphasis on the period December 2008 through mid‑March 2009 from a number of weather stations in Hampton Roads. They also examined reference wetlands in the cities of Hampton and Chesapeake that were studied in some detail from 2002 through 2005. After reviewing current and historic data as well as drought indices and regional analy‑ ses, we conclude that current and antecedent conditions are drier than typical and are unreliable for well data monitoring for wetland determinations. Therefore, we will not consider 2009 well data by itself, to constitute conclusive evidence that a par‑ ticular property in Hampton Roads vicinity is not a wetland. However, we will con‑ tinue to make wetland determinations based on the field indicators of vegetation, soils, and wetland hydrology described in the Interim Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Atlantic and Gulf Coastal Plain Region

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FIGURE 6.13  Dry river beds with water present take on a totally different look than their dry counterparts. Advanced techniques are required to help determine whether wetland char‑ acteristics exist. This example is from near Tucson, Arizona. (October 2008) for the Virginia Coastal Plain and the Corps of Engineers Wetlands Delineation Manual (1987) and associated guidance for the remainder of the state.

The Norfolk District determined, “As of March 13, 2009, the majority of the reference sites were far drier than they were during corresponding dates from 2002 through 2005. Analyses prepared by the U.S. Drought Monitor suggest that south‑ eastern Virginia is experiencing abnormally dry conditions.” It is appropriate here to present this finding and their work because it illustrates a level of adaptability and level of complexity that a given district can bring to bear on a given unusual condition (Figure 6.14). Though this may or may not be a harbinger for USACE practices, similar but less complex or less formal approaches may be used and communicated to the public in other USACE districts, to be able to conduct the regulatory activities and stay “true” to the laws, rules, and regulations. This example from the Norfolk District follows the “spirit” of guidance sup‑ plied in “Technical Standard/or Water‑Table Monitoring of Potential Wetland Sites” (USACE 2005):

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FIGURE 6.14  Under this highway bridge, wet soils, standing water, and the presence of wetland‑looking plants indicate that this may be a wetland. Spring flooding in Pima County, Arizona, poses the question. For many wetlands, water tables in a given year may be affected by precipitation that occurred in previous years, especially if monitoring occurs after an extended period of drought or precipitation excess. After a series of dry years, for example, it may take several years of normal or above‑normal rainfall to recharge groundwater and return water tables to normal levels. Therefore, in evaluating wetland hydrology based on short‑term monitoring, it is necessary to consider the normality of rainfall over a period of years prior to the groundwater study. Recent precipitation trends can be determined by comparing annual rainfall totals at the monitoring site with the normal range given in WETS tables for two or more years prior to the monitoring study, or by examining trends in drought indices. …

Again, this example demonstrates flexibility in interpretation, use of a variety of measures to understand conditions, and drawing upon guidance supplied to USACE documents resulting from a regional‑based research (Figure 6.15). Hence, it is impor‑ tant to stay attuned to such guidance or announcements (Sprecher and Warne 2000; Lichvar and Wakeley 2004; USACE 2009a–b, 2010a–f).

WETS Tables In these evaluations, one can also make use of precipitation data from National Weather Service (NWS) stations. The NWS data are available from their offices and archive in Asheville, North Carolina, at http://www.nws.noaa.gov/. Analyses can be developed based, say, on a standard 30 years of rainfall data. One can provide monthly and annual thresholds for the following conditions: below normal rainfall (lowest 3 years in 10 years); above normal rainfall (highest 3 years in 10 years); and other potential range con‑ ditions. Subsequent analyses of the current year of interest can be compared to previous

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FIGURE 6.15  Intense seasonal flooding like that shown here in the Salt River floodplain of Arizona again begs the question of whether this is a wetland. Field measurements, perhaps advanced measures, monitoring, and evaluation of frequency of events can all come into play when trying to sort this out (USACE 2009a–b, 2010a–f).

years of average conditions and cumulative analyses of conditions over the years. This approach provides for statistical analyses as well, and all can provide a perspective. The WETS tables can assist in these analyses and are generally useful and accept‑ able by regulatory agencies for analyses. The Website is located at http://www.wcc. nrcs.usda.gov/climate/wets_doc.html, where guidance can be found on their capa‑ bilities and utility for understanding precipitation and hydrological conditions. In essence, they are another tool that is acceptable for understanding and conveying conditions that influence wetland hydrology.

National Integrated Drought Information System and Drought Another way to understand drought and potentially how it can influence wetlands is to query the National Integrated Drought Information System (NIDIS; http://www. drought.gov or NIDIS.gov or http://www.drought.gov/portal/server.pt/community/ drought.gov/gis_resources). This is a very capable measurements and modeling sys‑ tem that can provide valuable details about drought conditions on a regional basis. NIDIS is relatively new, and hence wetland‑related applications are being devel‑ oped. It is a high‑quality system based on field monitoring of soil moisture and mod‑ eling and use of indicators. If you look back at the Norfolk District application and the use of a variety of informa‑ tion to assess drought conditions, it is apparent that NIDIS can be a resource in under‑ standing the regional conditions as they may influence wetlands and wetland hydrology.

Hydrologic Indicators Previous chapters and the Wetland Delineation Manual (USACE 1987) and supple‑ ments (USACE 2008a–e, 2009a–b, 2010a–f) discuss hydrological indicators. They

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FIGURE 6.16  Often the wetland characteristics all seem to be present, at least temporar‑ ily, creating ephemeral hydrology areas. Powerful water runoff carved this notch through a hillside near Sasabe, Arizona.

certainly can be useful in field evaluations of the hydrological criterion. A detailed study and listing of indicators has been done and can be found in Skaggs et al. (1994) and Noble et al. (2005). The work, publication, and USACE Web site describe the indicators currently listed in the Wetland Delineation Manual, other sources, and the 1992 field data form, as well as 53 possible additions (Figure 6.16).

Hydrology and Water Techniques The use of water well information for hydrologic interpretations can be useful. For given reasons, it may be desirable to install and monitor shallow groundwater wells in the spring to determine whether wetland hydrology is present in a particular area. There is no requirement to submit well data to refine wetland delineations. However, the USACE will consider well data as it would other data that contribute to the understanding of the property and wetland issues (USACE 2005). When reviewing shallow well data to determine whether wetland hydrology is present, one approach that can be considered is the use of cumulative precipitation totals for the 3‑month period prior to well monitoring compared to the cumulative precipitation totals for typical conditions (determined to be between the 30th and 70th percentiles of monthly precipitation totals for a given weather station over a 30‑year period). The distribution of rainfall events during this period is also an important consideration. A number of studies and references can be informative. They include Ward and Trimble (2003), “Accessing and Using Meteorological Data to Evaluate Wetland

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Hydrology,” (Sprecher and Warne 2000) and “Guidelines for Conducting and Reporting Hydrologic Assessments of Potential Wetland Sites,” (Warne and Wakeley 2000), and “Installing Monitoring Wells/Piezometers in Wetlands,” and these latter examples along with a number of other reports and information can be found at http://el.erdc.usace.army.mil/wrap/. Any monitoring wells used to facilitate wetland hydrology determinations should be installed in accordance with the guidelines in “Technical Standard for Water‑Table Monitoring of Potential Wetland Sites,” ERDC‑TN‑WRAP‑05‑2 (USACE 2005; available from http://el.erdc.usace.army.mil/elpubs/pdf/tnwrap05‑2.pdf) or other authoritative source. Again, this is a special activity for hard‑to‑evaluate sites. If such data will feed a permitting action, it is desirable in some corners to discuss the work with the USACE. Carrying out such a plan will take time, and time can be lost. Hence, in developing well data for a specific site, one may wish to provide a well monitoring plan for review as to the location and installation of the monitoring wells.

WETLAND SOILS The concept of hydric soils includes soils developed under sufficiently wet condi‑ tions to support the growth and regeneration of hydrophytic vegetation. Soils that are sufficiently wet because of artificial measures are included in the concept of hydric soils. Also, soils in which the hydrology has been artificially modified are hydric if the soil, in an unaltered state, was hydric. Some series designated as hydric have phases that are not hydric depending on water table, flooding, and ponding charac‑ teristics (Figure 6.17). The U.S. Department of Agriculture’s Natural Resources Conservation Service defines a hydric soil as “a soil that formed under conditions of saturation, flooding, or ponding long enough during the growing season to develop anaerobic conditions in the upper part” (USDA 1994). The National Food Security Act Manual defines wetland hydrology as an area that “… is inundated for at least seven consecutive days during the growing season in most years, or saturated at or near the surface for at least fourteen consecutive days during the growing season in most years. Soils may be considered saturated if the water table is within: −0.5 feet of the surface for sands −1.0 feet of the surface for all other soils.” (The soil surface is considered to be at 0.0 feet.) These definitions are used in support of USDA activities in and around wetlands, farmed wetlands, or “prior converted croplands.”

Soil Saturation Saturation of soils is an indication of wetland hydrology and is defined as when all soil pores are filled with water. This can be determined by observation in the field of surface conditions and by subsequent soil probing or digging of soil observation holes as suggested in previous chapters. It can also be determined quantitatively by other measures such as weight of soil cores or use of tensiometer measures and inter‑ pretation or the seasonal or yearly monitoring of ground water table, if required.

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FIGURE 6.17  After heavy flooding in arid areas, the ground sometimes looks like this. The flaky, pancake‑looking shapes are actually silt and clay deposits called invertisols. As the water recedes, the land dries and shrinks, leaving these shapes. This image is from Death Valley National Park in California.

Field indicators are soil characteristics that are documented to be strictly associ‑ ated with hydric soils. Field indicators are an efficient on‑site means to confirm the presence of hydric soil. The field indicators are designed to identify soils that meet the hydric soil definition without further data collection. Some hydric soils exist for which no field indicators have yet been recorded and documented, and to identify these soils as hydric, evidence must be gathered to demonstrate that the definition is met. Additional field indicators are being developed and tested all the time and can be used when advanced methods are required (Figure 6.18). Field observation of the soils and water table are very useful for gauging wetland characteristics. Previous chapters advocate excavation of a soil hole or pit on a grid and grid node basis. This is a valuable approach to help during field visits if a given location is where “the soil is saturated to the surface at some time during the grow‑ ing season of the prevalent vegetation” and “the depth to saturated soils will always be nearer to the surface due to the capillary fringe” (USDA 1994).

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FIGURE 6.18  Submerged soil samples retrieved from standing water help determine whether an area is a historic wetland. Here is a silty‑clayey soil pulled from beneath 10 feet of water in the St. Marys River in Michigan. Isoetes (quillwort) plants and residue confirm that this area could have submergent wetlands.

Hydric Soils Lists The lists of hydric soils were created by using National Soil Information System (NASIS) database selection criteria developed by the National Technical Committee for Hydric Soils. These criteria are selected soil properties that are documented in soil taxonomy (USDA 1962, 1991, 2010) and were designed primarily to generate a list of potentially hydric soils from the NASIS database. Hydric soil lists have a number of agricultural and nonagricultural applications. These include assistance in land‑use planning, conservation planning, and assess‑ ment of potential wildlife habitat. A combination of the hydric soil, hydrophytic vegetation, and hydrology properties defines wetlands as described in the National Food Security Act Manual (USDA 1994), USACE (1987), and USACE Regional Supplements. Therefore, an area that meets the hydric soil definition must also meet the hydrophytic vegetation and wetland hydrology definitions in order for it to be correctly classified as a jurisdictional wetland (Figure 6.19). The national list of hydric soils is maintained on a Web site and is updated yearly. The most current national electronic list of hydric soils may be obtained directly from this Web site. State lists of hydric soils are also available electroni‑ cally from this site or as hardcopy from the NRCS state conservationist in each state. The NRCS also maintains, for each conservation district in the United States, lists of map units that contain, or may contain, in some delineations, hydric soils. These detailed lists are available by contacting your NRCS state conservationist and are recommended only for preliminary use in making wetland determinations. Field indicators must be used for all on‑site determinations of hydric soils (USDA 1991, 1996).

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FIGURE 6.19  Soil probes are a good tool for evaluating soil and hydrologic characteristics. They can be used repeatedly and are suitable for confined areas. In areas with high water tables, delineators can draw a soil sample and observe how quickly the hole refills.

SOIL SURVEYS AND SOIL MAPS Soil surveys and soil descriptions in the county soil surveys are very useful in char‑ acterizing soils and helping with field assessments. Soil surveys are also valuable for getting the lay of the land in a given area whether on it is familiar and particularly so if it is unfamiliar. Generally they are good with respect to and if one remains respect‑ ful of inclusions and minimum mapping units disclaimers. Regulators no doubt rely on them for detail and for map‑like products. Often they were completed years ago and soil details are not obscured by development. Certainly if a known hydric soil is present on the soil survey map of a given piece of property, the delineator had better check it extensively because the regulators certainly will (Figure 6.20).

GROWING SEASON The growing season for plants is “… the portion of the year when soil temperature (measured 20 inches below the surface) is above biological zero (41 °F or 5 °C).” This can be found for a given county in the county soil survey (USDA 1991; Wakeley 2002). For operational purposes, this condition “[m]ay be approximated by the growing season definition, which is a period when the air temperatures are above 28 °F at a frequency of 5 years in 10 years.” This definition can be informed by details in soil surveys and WETS tables and by more advanced techniques or methods if required. Though seemingly mundane, the growing season duration as including in the county soil survey is very important. It anchors the local definition of hydric soils and saturated or standing water durations. Particularly in northern areas of the United States this period can be very informative in determining hydric soil conditions and duration of inundation or saturation.

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FIGURE 6.20  Images can help record data at each sampling location. A variety of low‑tech markers can be used to identify each location. Here a grid number written on a pad serves as a simple reference.

CALIBRATING HYDRIC SOIL FIELD INDICATORS TO LONG‑TERM WETLAND HYDROLOGY From the USACE Manual and described earlier, areas that meet the hydrologic crite‑ rion are required to be saturated to the surface for 5% or more of the growing season in 5 out of 10 years (Vepraskas et al. 2004). There is a need for field‑expedient mea‑ sures with the experimental backing that relate this test and the long‑term definition to the field methods. Vepraskas and his colleagues have worked hard on these issues and reported their results, but practical field methods for confirming this are lacking. Their study deter‑ mined whether hydric soil field indicators were related to wetland hydrology require‑ ments. Water table levels were monitored daily for 2.5 years in nine soil plots that included well‑ to poorly drained examples of soils. Monitoring data were used to calibrate a hydrologic model that simulated water table levels from inputs of hourly rainfall data. Forty years of rainfall data were then used with the model to com‑ pute long‑term daily water‑table levels in each plot. These data were summarized as saturation events, which were the frequency that water tables were at or above preselected depths for at least 21 days. Twenty‑one days was the average period needed for iron (Fe) reduction to begin in these saturated soils. This condition must occur for hydric soil field indicators to form, such as mottles. Regression equations were developed to relate saturation events to percentages of redoximorphic or redox‑related features. The coefficient of determination (r2) values for relationships between percentages of redoximorphic features and saturation events were >0.80 for depths of 15 centimeters (approximately

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6 inches) and >0.90 for depths between 30 and 90 centimeters (approximately 24 to 72 inches). Results showed that the depleted matrix field indicator, in which redox deple‑ tions occupy >60% of the horizon, occurred in soils that were saturated for 21 days or longer at least 9 years out of 10. This indicated that the depleted matrix indica‑ tors occurred in soils that were saturated nearly twice as long, and more frequently, than the minimum requirements needed to meet wetland hydrology requirements, meaning that for these soils and conditions redoximorphic wetland indicators were conservative measures of wetland conditions. This is a nicely executed example of quantitative work that informs soil sicence and provides a basis for field‑expedient, qualitative methods to evaluate hydric con‑ ditions in soils. Vepraskas and his colleagues’ work is also nicely described in his book with Curt Richardson (Richardson and Vepraskas 2007).

PLANTS AND SOIL CHEMISTRY There is a scientific basis for the behavior of the wetland‑loving plants and the plant dominance definition. These anaerobic conditions of wetlands result in changes in soil chemistry, which occasion the presence of soil chemistry indicators. Anaerobic condi‑ tions also occasion the presence of plants whose biochemistry and metabolic character‑ istics allow them to persist and procreate in the absence of oxygen as an electron donor. The absence or very low concentration of oxygen in soils results in forcing the pres‑ ence of plants that can tolerate and grow in these difficult conditions. This can be done by avoiding the conditions, say, by dormancy during spring floods, by either obtaining oxygen from another source via “plumbing” such aerenchyma or “trees knees” or by using another electron donor and biochemical pathways such as the malic acid cycle (Reddy and DeLaune 2008). Plants that are unable to cope with this stressful metabolic condition created by lack of oxygen die and hence “leave” and do not reproduce and are replaced by wetland‑loving or wetland‑tolerant species (Figure 6.21). Yet certain plants have adapted to persist and procreate there, in essence creating an ecological niche or “place of business” in exclusion of other competitor plants, also known as upland plants. The characteristics of this stressful environment are the very thing that make them a different, functional environment and the very thing used to identify their presence and their persistence over time (Figure 6.22). A fixed duration of flooding or saturation during the growing season is difficult to define based on local and regional conditions. This is difficult to state because plants vary in their tolerances and by region (hence, the plant list; Reed 1988). This is also difficult to predict because the solubility of oxygen is temperature dependent, as are many things. However, oxygen has a negative relationship with temperature and hence is different from many materials (Foth 1990; National Research Council [NRC] 1995). Naturally, this temperature dependence is sensitive to pressure that deviates with weather, latitude and altitude, sunlight, and other variables that are influential such as slope. Yes, this is a somewhat technical explanation, but the basic facts are that anaero‑ bic wetland environments are very stressful, and for reasons of the behavior of oxy‑ gen, flooding or saturation of soils, and plant metabolic pathways some plants live there and are wetland loving.

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FIGURE 6.21  Reed grass has taken over this wetland in Wayne County, Michigan (Lopez 2006 for reports of a study). Though it looks attractive, this plant has very little habitat value compared to other plants. It is a persistent invasive species.

FIGURE 6.22  This scene shows salt flats near the Great Salt Lake in Utah. High saline levels from runoff and ancient sea bottom deposits limit the utility of the area, yet all wetland functions are present.

Plants Often talented people find the work with plants mystifying. Hence, some thoughts on how to make this portion of the activity more understandable and straight forward are desirable. Identification of plant species can be daunting for those uninitiated into the botanical world. But it does not have to be so and can be quite enjoyable for many. Traditionally, taxonomic hierarchical keys are used and can be valuable for these evaluations, particularly when a specimen appears to be of one or two or three can‑ didate species. This often happens with specimens from the off‑season because

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fruiting bodies and/or flowers are not present and are often necessary to key out the final identity of the specimen. A particularly valuable approach is the use of lots of books with pictures. These contain keys, too, but the presence of a variety of drawings, images, and maps of distribution by state and counties in states can be invaluable. The Appendix holds the names of many of these books and visits to used book stores or Web sites can help build a library in support of these activities. The USACE has developed local and regional guides and Web support that can be a great help in this work. Examples include USACE (2006a–b, 2007, 2008a–e, 2009a–b, 2010a–f) and others such as Adamus et al. (1991), Andreas and Lichvar (1995), and Shafer et al. (2008).

Visual Estimates of Plants The assessment of plants and their dominance is a fundamental part of the wetland criteria. It offers the most challenge to many delineators because it is a subjective measure in a world now dominated with quantitative and analytical measures. The question is one of scale. If you have to evaluate large areas and estimate charac‑ teristics, a subjective but semiquantitative, field‑expedient measure is appropriate and necessary. In the plant and vegetation ecology and landscape ecology world these estimates are often done. If performed regularly, the user can be comfortable with their appli‑ cation and repeatability or precision. In earlier chapters this activity was addressed. Building upon that, one can go into the field and assess each canopy or layer of vegetation. Most humid area vegetation communities have a tree, shrub, and ground cover or layer. One can estimate abun‑ dance and assess dominance in each layer and then develop a composite estimate for all layers present. If the dominance estimate is made up of plants that are wetland loving in excess of 50% dominance, the wetland plant criterion is met. Visual estimates can be performed by a variety of people with practice. It can be a good practice to make assessment via vegetation layer in 10% increments for each layer and assign the plant list wetland indicator to each plant species encountered. One can later calculate the dominance and then average over the layers present. Over time a person can become familiar with and confident in visual estimations. This visualization technique has foundations in the vegetation community ecology literature and study of theory and techniques can be useful in the field. Estimates can also be made with several devices. These devices may have value for certain areas where the information is complex or where one can visit the site once and time is limited or where extensive documentation is required. Optical esti‑ mation, using scopes, prisms, and camera optics, is an approach. Typically, one takes a digital image of the site or a combination of image and field records. One can sweep the site, capturing the variety of vegetation present for documentation, and/ or use the optics to later determine plant characteristics such as areal extent, domi‑ nance, or measures of interest to remote sensing or plant ecophysiology studies such as Leaf Area Index (LAI).

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Optical integration of plant characteristics has been done effectively in one dis‑ tinct example. The U.S. Environmental Protection Agency (USEPA) conducted an extensive evaluation of sampling sites in the Neuse River watershed of North Carolina. They visited over 300 sites and recorded vegetation in the layers in support of land cover mapping for water quality monitoring and analyses. Use of an optical integrating device, vegetation assessment, and validation by botanists helped to cre‑ ate a high‑quality database accessible on the Web and to accurately assess later land cover mapping. This database serves a variety of activities, including training people in the utility of land cover maps by having them virtually revisit the sites as well as assessment of the vegetation communities that go into the land cover classes. The Neuse River virtual database can be found at http://www.epa.gov/ nerlesd1/ land‑sci/lcb/nrb/VFRDB/.

Specimens There is value in storing voucher specimens of plants taken from field sampling locations. This can serve a purpose when the delineator is beginning his work and encounters plants new to him or when he identifies a certain plant in abundance that is a “tie‑breaker” from either a wetland or upland determination of dominance (and could be called into question at a later date) or as a sample for comparative purposes. These samples can be saved by drying the plants in a plant press of blotter paper and thin panels or board secured by belt ties. Though a bit traditional, this method can maintain plants over time and allows comparison at a later date.

7

Advanced Methods, Mapping Sciences

MAPPING SCIENCES A good way to conceptualize the common elements and heritage of spatial technolo‑ gies is to view them broadly. It is valuable to organize these technologies mentally as the “mapping sciences.” This concept addresses the variety broadly without exclud‑ ing necessary examples. It also recognizes that the mapping sciences is a “toolbox” of methods that can be applied to wetland issues when the need arises. And like the old adage, one applies the “right tool for the job.” These tools and approaches are particularly useful in wetlands work (Figure 7.1). Wetlands are mixtures of terrestrial and aquatic land covers found across the land‑ scape. Their distribution, relationship with water conveyances, and need for location and characterization all argue for the application of these technologies. Of particular note in sorting through these issues are the capabilities of geographic information systems (GIS) and remote sensing to develop hard information on convey‑ ances of water or drainage patterns (Figure 7.2). Many determinations for jurisdictional purposes rest on the adjacency, connectivity, and path and sources of water. These technologies can help to build this informational base and make compelling documen‑ tation for the reality of the situation (Lyon and McCarthy 1995; Maidment and Djokic 2000; Lyon 2001; Maidment et al. 2001; Maidment 2002; Villeneuve 2005).

REMOTE SENSING AND GEOGRAPHIC INFORMATION SYSTEMS These modern technologies have historical antecedents, and they developed from earlier and useful technologies such as surveying, photogrammetry, photo or image interpretation, and the like. And they are useful for many different applications. Remote sensing is the practice of measuring an object from a distance or remote location using an instrument. In essence, it is instrumental sensing that is done with‑ out touching the object. This may be performed with an aircraft and a camera or sensor or with a spacecraft and sensor instrument system. Geographic information systems are technologies with antecedents in surveying, mapping, cartography, and information management technologies. GIS technologies allow the storage and processing of data in a spatial or map‑like reference system. The concept is over 30 years old, yet elements of GIS technologies have been applied for many more years. The myriad applications and the advent of lower cost comput‑ ing capabilities have made the discipline grow in a rapid fashion (Lyon 2003; Lopez et al. 2006). 113

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FIGURE 7.1  This aerial view of Buffalo Wallows in West Texas is from a color infrared image. Notice how the ponds, with their irregularly shaped boundaries, disrupt the otherwise regular pattern of rectangular land parcels.

FIGURE 7.2  Often geology dictates the location of water and wetlands.

Geographic Information Systems GIS are databases that usually have a spatial component in the storage and pro‑ cessing of data. Hence, they have the potential to both store and create map‑like products. They offer the potential for performing multiple analyses or evaluations of scenarios from model simulations (Lyon 2003). Data are stored in multiple files (Figure 7.3). Each file contains data in a coordi‑ nate system that identifies a position for each data point or entry. Characteristics of the data point are stored as “attributes” of the point. A database of individual files is developed and may contain files with characteristics such as stream locations, topog‑ raphy, management practices, and more.

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Ontario

Lake Superior

Minnesota

Lake Huron

Wisconsin

New York

Lake Michigan N W

E

Michigan Lake St. Clair

Illinois Indiana

S

0.0–2.5 2.5–5.5 5.5–9.9 9.9–19.1 19.1–65.1 Not Available

Lake Ontario

Percent urban adjacent to wetlands

Pennsylvania

Ohio

GLB Landscape Metrics 1 km of Shoreline Quantile

Lake Erie

0

200

100 Miles 0

100

200

Kilometers

FIGURE 7.3  GIS images and map products can be a great help in organizing and under‑ standing wetland issues (Lopez 2006).

The strength of the GIS approach lies in the quality of the database and how it can be used to address the application of interest. Each variable or “layer” in the GIS can be used in the application to develop information on function, processes, and characteristics of wetlands.

Format and Databases Remote sensor and GIS technologies organize data according to two general proto‑ cols. Remote sensors collect their data in grid cell or raster format, and GIS tech‑ nologies process data in raster or vector form or both as needed. GIS data are stored in files using one of two common methods, raster or vector. Raster storage is grid cell form and grid cells “build up” the image. Hence, a given area or polygon will be composed of a number of cells that have a certain area. The grid cells are referred to as “rasters” or as picture (“pix”) elements (“els”) or pixels.

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FIGURE 7.4  Low‑altitude images help reveal features across the landscape. Here, the build‑ ings near the top of the image, the tree line, and the curve in the road suggest a possible place to look for wetlands. Another place to look is shown along the lower right side. The normal rectangular land divisions are disrupted by what appears to be a stream and wooded area. Both areas deserve further examination to determine whether wetlands do exist there. The key things to look for on the low‑altitude images are adjacencies and clusters of indicators.

The other common way to store GIS data is in coordinate or vector form. A vector data set is stored as an x,y position for a point, two x,y positions and a line for a vec‑ tor, and/or a number of x,y points connected by line segments to form a polygon. Attributes are used to tag locations with information or metadata (Figure 7.4). An attribute is a characteristic or value of a variable stored in a GIS file. Depending on the GIS requirements, one or several characteristics or attributes can be stored for a given point or area. Attributes can be almost anything. Examples for a given point or area could include elevation; ownership; size or concentration; grid or map position; or a whole series of characteristics such as those pertaining to a given application. These attributes and position details and spectra can be organized. We often can access collections of data or databases and obtain needed information. The use of existing data can expedite analyses, help focus field sampling activities, and gener‑ ally ease the process of analyses to focus resources on the question at hand. An important thing to remember about data sources and databases is that they are inherently inexpensive, once they have been created and are available to the public. On a relative basis when compared to the costs of actual field sampling data, these sources can be acquired at lower relative costs and in a timely fashion. At a minimum, these sources can provide information for a reconnaissance‑level analysis before the more expensive and more detailed field evaluations are conducted (Lyon 1993, 2001). The data ease the planning process, allowing the investigators to “come up to speed” quickly and at minimal relative cost (Figure  7.5). The implementation of existing databases is vital to most projects for the reasons above. In measure to their importance, a number of sources for these data and databases are provided in Lyon (1987, 1993, 2001), Garofalo (2003), Ward and Elliot (1995), Ward and Trimble (2003), and mentioned here (Figure 7.6).

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FIGURE 7.5  This low‑altitude image shows low depressions and abandoned stream channel patterns that would probably not be visible to a delineator standing in the field.

FIGURE 7.6  Sometimes man‑made barriers affect a delineator’s ability to access a site. Ground‑level imagery and low‑altitude aerial photographs may be the only way to see whether wetland indicators are present. Captured here are battery casings stacked near a pond at a Superfund site in Oregon (Lyon 1987). It is likely that wetlands are bordering the pond, but without collecting ground‑truth data it is hard to be certain.

MAPS Maps are often the starting point in an analysis and often are used in the presenta‑ tion of results in reports. They can capture attributes and their spatial relationships in image form. U.S. Geological Survey (USGS) and other original source maps may be used to obtain a variety of information. They can be used to take point position infor‑ mation; topographic contour information, and they include cultural or planimetric details such as roads, waterways, dwellings, or public land ownership boundaries

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FIGURE 7.7  A ground‑level image taken near (Figures 7.6 and 7.21), but facing away, shows why there might be a concern about wetlands here. The site borders the lower Willamette River in Oregon.

(Figure 7.7). The maps can provide the starting point to form a variety of land cover themes or layers in a GIS. Engineers often have large‑scale maps available in digital form for site planning and design as discussed earlier. The scale is commonly 1 inch:100 feet or 200 feet. The contour interval is often one foot of elevation. These products are especially useful in hydrological analyses, and they are created through surveying or a combi‑ nation of surveying, photogrammetric, and/or light detection and ranging (LIDAR) technologies (Shan and Toth 2008).

DIGITAL ELEVATION MODELS Digital elevation models (DEMs) are map‑like products stored in computer files com‑ posed of x,y grid locations and point elevation data or z variables. They are generated in a variety of ways and from a variety of map scales by the USGS and by commer‑ cial firms. These files are produced as part of National Mapping Programs and are provided in large‑scale 1:24,000 scale or 7.5‑minute and 1:62,500 scale 15‑minute products, intermediate‑scale 30‑minute or 2‑arc‑second products, and 1‑degree unit small‑scale products. The elevation data are very useful for a GIS and wetland resource activities (Lyon 2003). The data can be further processed to yield important derivative products, including digital maps of wetland resources, watershed characteristics (Lyon 2003) and related attributes such as slope or slope aspect. With more detailed image pro‑ cessing, water channels and subbasin information can be derived. Stream channel or network information can be the data input for more complex analyses, including route of water flow and to address connectivity of water courses (Lyon 2003).

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These capabilities point to the value of identifying and locating water conveyances and of GIS and related technologies in supporting jurisdictional analyses. They will be subject to detailed discussion later because they can facilitate data gathering and analyses of jurisdictional questions.

DIGITAL TERRAIN MODELS, DIGITAL LINE GRAPHS, AND OTHER DATA Digital terrain model (DTM) data are an additional product created by a number of groups. DTM data provide digital topographic contours at a variety of scales. As with DEM products, these DTM data are available from commercial firms, the USGS, and local or regional sources. Digital line graph (DLG) data are available from the USGS and others, and they provide map‑like presentations of the road network and stream courses for many USGS quadrangle areas. The data make very nice “overlays” of remote sensor or other map data, in addition to providing important detail on the location of road and road types and larger stream and river connectivity. A digital raster graphic (DRG) is a scanned image of a USGS standard topo‑ graphic map, including all map information. The map image is georeferenced to the surface of the Earth using the Universal Transverse Mercator (UTM) map projection and scanned at a minimum resolution of 250 dots per inch. The horizontal positional and vertical accuracy are the same or similar to the original map product (Falkner and Morgan 2001). The USGS National Hydrography dataset provides digital stream course data use‑ ful in connectivity and isolated wetlands determinations (nhd.usgs.gov).

SURVEYING Surveying is the science of obtaining precise and accurate measurements of the Earth’s surface or its waters using instruments. These measurements include horizon‑ tal locations as well as vertical or elevation locations (Van Sickle 2008). Commonly, these measurements are tied to some absolute reference to characterize the location of Earth features in an absolute sense and allow later relocating these features using the original measurements or map products (Figure 7.8). Surveying is important in wetlands and hydrology, because these measurements form the basis of many wetland area and hydrological calculations (Shah and Toth 2008). The surveyed positions of basins, subbasins, channels, control structures, and the like all form important inputs to calculations for water connections and wetlands. These positions may also provide the basis for GIS databases and form GIS model calculations (Van Sickle 2008). Surveying is also important in the production of photogrammetric products (USACE 1993; Falkner and Morgan 2001). In general, to make photogrammetric calculations in absolute units and to reference measurements absolutely, it is neces‑ sary to collect ground‑surveyed positions or use Kinematic GPS. These positions or ground control points (GCP) allow the stereo model to be tied into absolute ground

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FIGURE 7.8  Subtleties come out in low‑altitude imagery. In the top right, the darker‑toned zig‑zag pattern is where the crop planter halted at the end of the field rows. In the middle right, light‑toned soil shows through the plant canopy where foliage or stems are missing.

positions. Surveying is also used to mark the positions and follow the progress of field construction and ensure that the engineering design specifications are met, such as the design and subsequent construction and avoiding jurisdictional wetlands. These measurements and resulting engineering‑style maps or plans are also valuable in design and location of mitigation wetlands (Figure 7.9). An exciting arena is that of global positioning systems (GPS) surveying. GPS can be used in taking measurements and reference control for photogrammetric mea‑ surements, among other applications (Falkner and Morgan 2001; Van Sickle 2008). An example application of this work would be the staking of a water conveyance or wetland such that any modification would, for example, help to create more fish habitat and reduce erosion as well avoid any trafficking during construction (Hook et al. 1995).

PHOTOGRAMMETRY Photogrammetry is a very valuable technology that has provided many years of service. Almost all maps showing horizontal positions, point elevations, elevation contours, and/ or topographic maps are made using photogrammetric technologies. Photogrammetry is the science of obtaining precise and accurate measurements from overlapping or ste‑ reoscopic photographs or images (USACE 1992; Lyon et al. 1995; Falkner and Morgan 2001). The products mentioned previously such as DEMs, DLGs, and other spatial products including maps are often made using photogrammetric means. Commonly, photographs are taken from an aircraft platform, and individual exposures record the ground under the aircraft. The photos are taken such that an

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FIGURE 7.9  The light‑toned areas in this field show where foliage and plants are absent. There appears to be a diagonal border to the light‑toned areas from the lower left up toward the upper right. This is probably the outermost boundary on the valley bottom where the stream (far left) meandered across the land over thousands of years.

individual photo includes ground coverage of the previous and next exposure in a series or flight line of overlapping photos. These photographs are called stereoscopic pairs. The difference in perspective of a common feature photographed from differ‑ ent positions is called parallax. The relative parallax or difference in position of a given feature on the pair of exposures creates the stereoscopic effect and allows us to determine the elevation position of features in addition to their horizontal relative positions (Figures 7.10 and 7.11). Photogrammetry is important because it is often the most cost‑effective method to make topographic maps. In the past, almost all USGS or National Oceanic and Atmospheric Administration (NOAA) topographic maps were made from aerial photographs using photogrammetric technologies. Most large‑scale engineering maps are also made from aerial photographs. Hence, most of the products that are used in hydrological analyses are made from photogrammetric analysis of aerial photographs or images (USACE 1993; Falkner and Morgan 2001). Now, a number of watersheds are characterized using point elevations generated by laser LIDAR systems (Falkner and Morgan 2001; Shan and Toth 2008). Vertical, overlapping photographs can be valuable for photogrammetric mea‑ surements and for photointerpretation. Photogrammetric measurements from aerial photographs can document historical conditions and change over time (Lyon 1987, 2003; Williams and Lyon 1995; Garofalo 2003). This is particu‑ larly true of hydrological events that cause change. This information is valu‑ able for scientific, engineering, and legal studies and is quantitative in quality (Figures 7.12 and 7.13).

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FIGURE 7.10  An odd‑shaped pond and adjacent ditch wetlands are in the lower right of this low‑altitude image. The farm field bordering these areas on the right appears to be either an old abandoned field or perhaps part of a cropland reserve program. The cropped fields along the top and the upper right have a distinctly different texture and pattern from active fields on the left. The shape and apparent depth of the pond indicate that extraction activities may have occurred here at one time.

FIGURE 7.11  The similar area from a more distant view tells a great story. The previ‑ ous close‑up allows detailed examination, whereas the distant supplies more context and association.

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FIGURE 7.12  Advanced methods can assist in wetland identification in the off‑season or nongrowing seasons of the year. This is important because work goes on year‑round, includ‑ ing permitting. Here we see a winter scene of the Scioto River in Franklin County, Ohio. The river banks, floodplain, mid‑channel fluvial deposits, and other land features are readily apparent in the absence of foliage. This may be a riverine area or it may be a wetland area.

FIGURE 7.13  This is the same area in summer. The fluvial deposit supports wetland vegeta‑ tion during the growing season. The river banks have trees, shrubs, and other foliage that are not indicative of wetlands. With the exception of the fluvial deposit area, this site is riverine, not a wetland.

TOPOGRAPHIC INFORMATION Wetlands are often occasioned by the drainage and ponding of water, which can be governed by the two‑ and three‑dimensional characteristics of the surface. The addi‑ tion of planimetric and topographic information can be very useful in the identifica‑ tion and delineation of wetlands.

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Typically, surface information has been obtained by surveying and by photo‑ grammetric means. Resulting products such as maps in the old days and digital files presently have been converted to digital products discussed in the mapping sections (e.g., DEMs, etc.). The advent of airborne or space‑borne laser ranging sensors using coherent light or LIDARs has been revolutionary (Shan and Toth 2008). The value of these data products is evident in the advancement of floodplain mapping. In the wetland arena, LIDAR mapping products provide great detail on two‑ and three‑dimensional sur‑ face characteristics. LIDAR measurements can be made such that the plant or forest canopy can be measured, as well as the Earth’s surface. Subsequent mapping from LIDAR allows much of this information to be inte‑ grated into a two‑ or three‑dimensional form. GIS can store data for retrieval and facilitate the interpretation of the point sampling in the continuum of two and three dimensions. Analysis techniques also allow the extrapolation or interpolation of data by providing a scientific basis of interpolation between points rather than just a mathematical basis such as kriging. These sources of information can be of great utility in the multispectral approach to land cover characterization. Much as radar data can be combined with visible and infrared sensing, LIDAR data are also combinable to make products that add new information to the analyses such as relative crown height, and hence value. DTM datasets from LIDAR can be used to construct watershed and connectivity data for determinations (Maidment 2002; Lyon 2003).

FLOODPLAIN MAPPING The Federal Emergency Management Agency (FEMA) supports and distributes a number of products that may be of assistance in permitting activities. An example is the Q3 Flood Data product in support of FEMA’s Response and Recovery activities and flood insurance policy marketing initiatives. The Q3 Flood Data can be used in floodplain management, hazards analysis, and risk assessment activities. The digital data product contains a subset of information derived from paper flood insurance rate maps (FIRMs) usually derived from surveying and photogrammetry. Q3 Flood Data were developed by electronically scanning the existing paper FIRMs. Certain key features are digitally captured and then converted into area features (floodplain boundaries, flood insurance zones, political boundaries). Using computer mapping software, you can overlay the Q3 Flood Data with your own infor‑ mation (general wetlands, land parcels, transportation networks, customer addresses, etc.) to display zones of potential flood risk. Such floodplain information can provide details as to water conveyances, adjacency, and potential regulators interests. Q3 Flood Data include the 100‑year and 500‑year floodplain areas (1 and 0.2% annual probability or chance of flooding, respectively). This also includes Zone V areas, certain floodway areas, and zone designations; Coastal Barrier Resources Act (COBRA) areas; other political boundary or jurisdictional areas, including com‑ munity identification number; FIRM panel areas, including panel number and suf‑ fix; and the appropriate USGS 1:24,000 scale topographic quadrangle information, which can aid in navigating all the mapping and other information together.

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It is important to note that with all digital data or paper mapping products that changes occur over time, and the user should confirm the quality of the information through query of the provider’s Web site and in the field. This approach can be used with a number of mapping products, but remember to be careful of enlarging the resulting product and potential distortions. This can result in miscalculations of accuracy and precision with an enlarged product different from the original mapping scale and intent of use (Falkner and Morgan 2001).

NATIONAL WETLANDS INVENTORY The coverage in the United States is mostly complete and can now be somewhat dated. However, it is a useable source of information, particularly in first analyses (Figure 7.14). Certainly, the regulators will make use of the coverage even though it may be incomplete because it is another regional source and is mostly uniform. The coverage can include 24K coverage maps or 100K coverage maps at mapping scales of 1:24,000 and 1:100,000 respectively. Further details can be found at http://www. fws.gov/wetlands/ for general information and for downloads of digital data or http:// www.fws.gov/wetlands/Data/index.html for an index. The wetland boundaries are supplied as polygons in shape file format. Early use of the digital products was conducted by Williams, Gauthier, Lunetta, and Lyon and is reported in Williams and Lyon (1991, 1997) as well as others (Scieszka 1990; Thompson and Gauthier 1990; Schaal 1995). More current efforts make use of Web mapping services, and these may be helpful, as would the use of USGS topographic maps. Web mapping service capabilities can be examined at http://www.fws.gov/wetlands/data/WebMapServices.html.

FIGURE 7.14  Note the presence of a limestone quarry and general wetlands along the Scioto River in the Columbus, Ohio, urban/suburban environment. The location of Figures 7.12 and 7.13 are at the right edge of Figure 7.14 on the black-toned river.

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For the latest National Wetlands Inventory (NWI) digital data, the site and related examples supply capabilities to build, search, query, and download cus‑ tom digital maps and data in the area you choose. By using the Wetlands Data Extraction Tool you can download current seamless wetlands data as viewed on the Wetlands Mapper. All data downloaded using the Wetlands Data Extraction Tool will be in the geographic coordinate system (GCS) with a North American Datum (NAD) of 1983. With each download you will receive a .zip file that contains one or all of the following shapefiles: Wetland_Polygons, NWI wetland polygon data; Metadata, NWI project metadata including image dates used for mapping; Historic_Map_Info, NWI historic map report information. See http://wetlandswms.er.usgs.gov/imf/imf. jsp?site=extract_tool. In addition, these and other data are available on The National Map (Figure 7.15). See http://nmviewogc.cr.usgs.gov/viewer.htm.

FIGURE 7.15  An aerial photo of the same Olentangy River area as Figure 6.11 from a his‑ torical archive. Note the scale quantities of each product. The relatively small scale of aerial photos can be a challenge that can be overcome with practice and experience. The combina‑ tion of fieldwork and images, low altitude and higher altitude, and thematic and topographic maps all help with the convergence of information.

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FIGURE 7.16  A USGS topographic map of the same Olentangy River area (Northwest Columbus, Ohio, quadrangle 1:24,000 scale, from 1965).

Also, limited amount of raster data (scanned) for nondigital maps are now avail‑ able on the Wetlands Mapper and via our WMS service for viewing in ESRI’s ArcGIS (http://www.fws.gov/wetlands/data/WebMapServices.html). Whether on paper maps or in digital form, NWI information is potentially useful for general wetlands. One should pay attention to the disclaimers, which are important because most mapping products are created at a certain resolution or scale and need to representative (Figure 7.16). Very simply, the NWI presents general wetlands and jurisdictional wetlands as mapping from aerial photos or images over time (American Society of Photogrammetry and Remote Sensing [ASPRS] 1995). Remember the details of the methods of their assembly and the disclaimers (Falkner 1993). Certainly, regulators and others view these NWI maps with an eye to jurisdic‑ tional questions. You also need to be aware of their information content for a given site (Figures 7.17 and 7.18).

DETAILED MAPPING AND GIS An important capability of GIS is the simulation of physical, chemical, and biologi‑ cal processes using models. GIS can be used with deterministic or complex models composed of algorithms that simulate processes, or they can be applied with statisti‑ cal or stochastic models or with simple models as in wetland landscape ecology work (http://www.epa.gov/nerlesd1). The requirement is that the model to be applied has the

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FIGURE 7.17  An additional mapping product from the same location. Note the Ohio State University Stadium here on on the photos and map. Figure 6.11 is located in the lower right and in the lower middle portion of Figure 7.16 where Lane Avenue bridges the Olentangy.

capability to take spatial and/or multiple file or layer data as input to computations and yield some meaningful information on issues such as wetland function and/or wetland water treatment capabilities (Kang et al. 1994; Ji and Mitchell 1995; Ji 2007). GIS databases and products are also amenable to evaluations of general wetland identification quality. It is an important aspect of these efforts to document the qual‑ ity of the data and determine the accuracy of the product. A number of methods can be used to conduct an assessment of accuracy (Congalton and Green 1998; Lunetta and Lyon 2004), and these approaches can be implemented in the experimental design (Congalton and Green 1998, 2009).

WEB SERVICES The utility of Web mapping services has found favor by the public. It is great to see people using these capabilities, such as Web‑based satellite or airborne remote sens‑ ing products, LIDAR, and GPS to add value to their daily lives. Naturally, people will use these technologies in wetlands‑related work, which is fine, remembering the strengths and accuracy characteristics of the products. Google Chrome, Google Maps, Microsoft Virtual Earth/Bing Maps, Mapquest, and so forth supply information and the capabilities of mapping and remote sensing for the layperson and are pretty evident in our modern world of GPS and digital maps. As per the old saying, “Everyone is doing it …” is little comfort to those who hold dear film‑based photography, phonographic recordings, magnetic tapes, and paper maps. Yet from the ashes comes a marvel of technology that all can use, not just the aficionado or the specialist. The use of Web services and Keyhole Mapping Language (KML) products has proven to be of value. A good source of information and assistance is from the

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FIGURE 7.18  A National Wetland Inventory product for the part of Atlanta, Georgia, area. Note the presence of mapping general wetlands in the urban/suburban environment.

OpenGIS Consortium (Wetlands Mapper: [email protected]). Making use of the Consortium capabilities, the U.S. Fish and Wildlife Service (USFWS) and oth‑ ers can supply good regional information. For watershed or state‑level data, contact the Regional Wetlands Coordinator or [email protected]. The digital realm can go beyond the capabilities of Photoshop® and Google Earth and Maps. With high‑quality digital imagery one can enter the image processing realm, which has decades of experience in teasing out details of multiple spectral images. Image sharpening and image fusion compositing of different images from

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different parts of electromagnetic spectrum can supply image enhancement products for applications. These approaches are detailed elsewhere but are mentioned here for both their place in the wetlands arena and to supply ideas to the users.

REMOTE SENSING AND MAPPING OF WETLANDS The practice of remote sensing is generally defined as sensing features or materials without direct contact with the material. Often this approach will use electromag‑ netic energy that is either sunlight “bounced off” or reflected from a material or one will create one’s own light, if you will. This could be as simple as shining a flash‑ light at night, or using a source of microwave radiation such as radar to illuminate materials directly so as to create one’s own radiation sources without the use of sunlight. For example, reasonably priced night‑vision capabilities are now available to the wildlife scientist or ecologist to study night behavior of wetland creatures and plants. Multiple spectra and their integration can result in a multispectral product for analysis. The combinations may take on many forms, because the product is results oriented or outcome driven (Figure 7.19). The use of composite images from different sensors is called data fusion, which is a topic of great interest. This is because the synergism resulting from different spectral or spatial views of the same terrain can yield unique information. The sum is greater than the individual parts. One can combine three images and make a color composite image and later con‑ duct manual or semiautomated or automated interpretations (Rundquist et al. 2001). This represents data fusion in its simplest form. One can make unlimited combi‑ nations with fusion, always guided by hypotheses as to what information can be gleaned (Figure 7.20). A combination of these and other databases can help to establish the location of water conveyances (Jensen et al. 1993; Kadmon and Harari‑Kremer 1999). Combined with large‑scale topographic, engineering‑style maps of a given site they can provide a good synthesis of water conveyances that will influence or establish jurisdiction (Lampman 1993; Jakubauskas et al. 2000). They can also identify places to search in the field for water conveyances and potential wetland areas (Figure 7.21).

Remote Sensing Remote sensor technologies can be used to acquire a variety of data for applica‑ tions. A number of these technologies can supply a wealth of data and acquisition can be potentially accomplished at a lower cost than many other technologies (Lyon 2001). These advantages have attracted great interest in the wetland community (Figure 7.22). To apply remote sensing technologies, it is necessary to identify the application and the characteristics that may be measured by the remote sensor (Rouse et al. 1973; Roller 1977; Remillard and Welch 1993; Sader et al. 1995; Tiner 2003a; Torbick 2004; Wang et al. 2007). These characteristics or variables may be measured directly by

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FIGURE 7.19  Aerial photos from archives can be a great source of historic information including land use, agricultural history, earthmoving activities, and natural phenomenon. Note the abundance of Oregon oak woodlands and wetlands in the top center of this image. The site is Ridgefield National Wildlife Refuge in Washington and Sauvie Island in Oregon, each separated by the Columbia River.

the sensor or indirectly through measurement of a surrogate variable whose behavior is correlated to the variable of interest. Then, we can select the appropriate technol‑ ogy or tool from a suite of technologies. This selection is made with the knowledge of the characteristics or variables to be measured, the available budget and resources, and time frame of the project. This is tricky with wetland land covers, because such interpretation and analyses can be complex (Figure 7.23). They are a mix of materials, and these approaches will be discussed later. To implement a remote sensor technology for monitoring requires knowledge of the problem, the characteristics that can be measured remotely, and a plan for col‑ lecting the requisite data (Johnston and Handley 1990; Lyon 2001; Heber 2008). The budget available to support the effort is very important. It can be influential in the selection of the methods and instruments to be used as well as to generate the accu‑ racy assessment of resulting products (Lunetta et al. 1991; Becker et al. 2007).

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FIGURE 7.20  This image shows clearly the abandoned river channels or sloughs on either side of the Columbia River. Though they can be seen on the ground, the vertical view makes them more apparent and their association with the river obvious.

Photographs and Images Photographic products have well‑known characteristics and can be used in a vari‑ ety of forms to collect and store original data or for the production of derivatives. Photographs use silver‑halide chemistry to capture a black‑and‑white or color images on film (transparencies) or paper. As such, photography using cameras is a remote sensor technology. It has a number of advantages in that the products are usu‑ ally available and are often low in relative cost compared to other sensor products (Figure 7.24). Aerial photos or images are acquired constantly to support science and engineer‑ ing activities. These photographs are usually saved after the initial project and may be later obtained from a variety of sources (Figure  7.25). Historical aerial photo‑ graphs are particularly valuable because they are a record of a variety of conditions, including hydrology (Garofalo 2003; Lyon 2003). They can be obtained and used in a variety of analyses and applications (Lyon et al. 1986; Lyon 1987, 2003; Williams and Lyon 1997). Aerial photographs can be obtained from a number of sources. They include the USGS, the U.S. Department of Agriculture (USDA), NOAA, state natural resource and transportation agencies, local aerial photography firms, and other valuable sources (Lyon 1993; Ward and Trimble 2003). Their utility has been illustrated here in other chapters and in figures and figure captions.

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FIGURE 7.21  Lake Vancouver, Washington, illustrates peripheral wetlands around in the lake. Note how the mirror‑like water surface is interrupted and mottled by the emergent wet‑ lands, helping to identify their boundaries.

FIGURE 7.22  A low‑altitude image of a river bend shows common features including chan‑ nel point bars and deposition of sediment inside the river curve. Outside the river curve, the water is excavating sediment from the banks.

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FIGURE 7.23  A low‑altitude shot from a small aircraft captures a great deal of detail. Note the very large deciduous forest in the center of the image, with a pond wetland near the forest center bottom. From this height, more subtle variation in texture and tone can be seen in the center forested area. Upon ground inspection, this area proved to be a depressional wetland or bog hidden in the forest.

FIGURE 7.24  The polka dots in this image are from center‑pivot irrigation systems. Note the dark‑toned areas of crop so different from the light‑toned soils and riverine deposits.

Images are defined as two‑dimensional, pictorial representations of data. Images are often presented as nonphotographic data, and they are usually the result of com‑ puter systems. The word image helps to identify and separate the photographic‑image products that are so common from the pictorial presentation of data or results from computer processing systems. The advent of relatively inexpensive software and very capable digital cameras has opened a whole new world for digital imaging.

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FIGURE 7.25  Many people are used to looking at land below out of the window of an airplane. The view is off to one side but still above the site. This is called an oblique view. Oblique view images are very useful for reports and public presentations. This image shows a lake or reservoir near a town surrounded by forests.

Parts of the Spectrum and Radiation Characteristics Remote sensing inherently measures light. Light or electromagnetic radiation ema‑ nates from the sun, is propagated through the atmosphere, strikes and interacts with the Earth’s surface, returns through the atmosphere, and is ultimately measured by the remote sensor or film above the Earth. Many valuable portions of the light spectrum can be sensed. In particular, wet‑ land and water characteristics are identified using visible, near, and thermal infrared; microwave or radar; and sonar sensors. The selection of the appropriate portion of the spectrum and sensor is based on the application and the cost of using the sensor (Figure 7.26). There are a variety of light types, and these are usually measured based on the perceived information that can be obtained about a feature such as water. Hence, only a portion of the total spectrum of electromagnetic energy is measured, and this is called a spectral measurement.

Visible, Infrared, and Thermal Infrared The visible portion of the spectrum is found approximately from wavelengths between 0.3 micrometers and 0.7 micrometers. This is the part of the spectrum that the human eye is sensitive too, and, no surprise, it is the same part that black‑and‑white and color film and/or digital cameras sense to produce photographic images that capture scenes in the ways human see. The infrared portion of the spectrum is just beyond what a human may see. The “reflected infrared” is found approximately between 0.7 micrometers and 1.4 micrometers, and the “middle infrared” is found between 1.5 micrometers and 2.8 micrometers. Infrared images are useful in wetland studies because they can identify

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FIGURE 7.26  Low‑altitude vertical imagery (shot from directly above a site) is an extremely value tool for delineators. Note the presence of dark tones in the forest. Wetland marsh areas show up as a more uniform gray tone.

the presence or absence of water conditions via change in relative reflectance or tone. Note that clean and deep standing water is black in tone because water readily absorbs near‑infrared radiation. Conditions include standing water, soil moisture or saturation, and absence of significant moisture (Figure 7.27). Color and color infrared (CIR) photography or imagery is also very valuable for hydrology‑related analyses. The CIR image can facilitate interpretation of water resource characteristics and general vegetation types and conditions. The stereoscopic coverage allows viewing of relative topography and the shape of tree canopies. The thermal infrared (TIR) is a measure of the heat emitted from features. TIR is found between 3.0 micrometers and 14.0 micrometers, and it provides very good information on features resulting from their emission of heat. All features emit ther‑ mal infrared radiation and, as such, TIR can be used for detection both night and day. Most TIR sensors that record the passive emission of light energy from a feature are called passive sensors.

Radiation One of the great capabilities of remote sensing is the fact that light can be measured or modeled in a quantitative manner. Photo or image interpretation is inherently qualitative, though photographic or image generation processes may be the subject of quantitative analyses. Remote sensor data are digital as they come from the sensor and can be processed in the same fashion as any digital product. With these charac‑ teristics it is possible to model the characteristics of light and sensors and predict the behavior of measurement experiments beforehand. Generally speaking, electromagnetic radiation is radiated in three ways, and most materials exhibit a dominant way as well as a combination of other phenomena

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FIGURE 7.27  Enlargement of aerial photos can make viewing easier, although it may dis‑ turb the metrics of the image (Falkner 1994; Falkner and Morgan 2001). The Muskingum River is the giant shepherd’s hook shape along the right side of the photo. On the lower left, wetland areas are dark toned.

depending upon material characteristics. A diffuse or Lambertian source radiates light equally in all directions and is the most common or dominant phenomenon. A specular source has a particular angular orientation to the reradiation of light; the glare or sunglint one sees on water surfaces is a great example of specular reflectance. Bidirectional radiation refers to the nondiffuse behavior typical of many materials. We can think of it as a combination of the above two ways of radiation. Most objects that we measure on the Earth exhibit a combination of these phenomena, and the types and quantity of light encountered will be wavelength dependent (Figure 7.28).

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FIGURE 7.28  Satellite or aerial images can be of fine resolution and multiple spectra are captured. They can be analyzed digitally to reveal additional information. The image is the Gulf Coast of Texas approximately 2006.

The measurement of light energy is usually separated into types based on the quantity and variety of light under study. Radiometry refers to measuring all avail‑ able light, or at least all the light that can be measured by your particular sensor. Spectral measurements refer to the fact that we measure discrete wavelengths or frequencies, rather than the whole. Spectral units are employed to record a quantity of energy per unit of wave‑ length. These units are encountered whenever per wavelength units are reported. Examples include graphs of reflectance; radiometer measurements; or engineer‑ ing data on instrument response per unit wavelength in a certain portion of the spectrum. For additional discussion of these geometric and electromagnetic radiation characteristics, please consult a detailed text (e.g., Milman 1999; Campbell 2002; Lillesand et al. 2004; Jensen 2006; Campbell 2007).

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FIGURE 7.29  Floodplain areas can be a source of wetlands particularly in arid areas such as this. Note the dark tone of drip‑irrigated farm fields as well as a dark line of cottonwood trees along the river channel.

GENERAL WETLANDS In previous efforts, the authors have coined the concept of either a potential juris‑ dictional wetland or a general wetland. The objective was to create an operational definition to be able to identify wetlands or wetland‑like features from a distance (Lyon 1993, 2001). This definition can facilitate medium‑ and small‑scale invento‑ ries of features so important to management and ecological studies. It also allows the use of remote measurement or remote sensing approaches that often yield great details on general wetlands yet may not supply enough detail for a jurisdictional characterization in the strict sense of the wetland definition and laws, statutes, and rules (Figure 7.29). Though this concept may not have caught on, it is important to have an opera‑ tional definition to allow good work to advance. A mapping example of such an operational definition is that of the minimum mapping unit, where a finite resolution is defined and results are analyzed based on the criterion. A great challenge in wetlands is the mixture of materials that make up and create their presence. The variable and complex combination of plants, soils, and water can confound most analyses, yet great work has been done over the years. This issue will be discussed in a number of places because it is an important capability yet can be tricky.

SPECTRAL ANALYSES Spectral measurements of materials can greatly help in the understanding of the spectral differences of those same materials. Wetlands are particularly problematic in the identification and their separation from other land cover types. This is partially

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due to their inherit mixture of materials types, plants, soils, and water. Mixtures have generally been difficult to separate from the pure land cover types or from two mixture types such as soils and plants or plants and water or water and soils. Over the years technologies have been developed to address wetlands and the myriad of wetland subtypes, and again they are very similar in spectral mixtures to upland land cover types (Figure 7.30). The very advanced techniques utilize spectral differences to identify and separate materials. Much work over the years has been conducted on the spectra of plants, water, and soils, as well as combinations of the materials. Early work in the 1960s and 1970s by such leaders as H. Gausman, David Gates, Charles Olson, Ronald Lyon, W. Allen, J. Richardson, Virgina Carter, Mary Butera, G. Suits, the Purdue Laboratory for Applied Remote Sensing, U.S. Department of Agriculture Agricultural Research Service laboratories, University of Michigan and University of California Berkeley laboratories, USEPA Laboratory in Las Vegas, and Department of Energy (DOE) or National Laboratories pioneered the technologies and created a foundation. This work was advanced through the 1980s and 1990s both in the laboratory and field and in airborne and space‑borne studies.

FIGURE 7.30  The angle of observation and lateness of the day create shadows that enhance the viewing of features. Note the pitted wetland landscape in the middle right of the image. Shrub and tree shadows along with the dark‑toned water and plants look different from the crop and soils in nearby agricultural lands.

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The advent of operational, multiple spectral analyses or multispectral work has greatly advanced the utility of these approaches and demonstrated valuable experi‑ mental and operational results. The 1990s and new millennium have seen the devel‑ opment of multispectral as well as hyperspectral and ultraspectral measurements and modeling (Thenkabail et al. 2011). Now, the combination of a variety of sensor products and image processing analyses yields great information. Again, this can be addressed by identification and location of general wetlands or potential jurisdictional wetlands and characterizing their spatial distribution as compared to the location and drainage of water conveyances.

DETAILED REMOTE SENSOR ANALYSES Detailed spectral measurements can supply valuable detail on processes and help characterize materials. These spectra may be collected from lab research, the field, or above the Earth. Anderson and Perry (1996) supplied a good example of how valu‑ able these measures can be for wetland analyses. Their work characterized flooding, plants species, and redox conditions. In Anderson and Perry’s (1996) experiments, spectral measurements were recorded for red maple (Acer rubrum) leaves to characterize leaf reflectance at different stages of flooding. The experimental sites had two different soil types possessing different soil moisture regimes. Leaves were taken from different parts of the trees, and their reflectance properties were measured with a handheld spectroradiometer recording from 400 nanometers to 900 nanometers in 3‑nanometer increments (Figure 7.31). Soil redox potentials were recorded at the sites in an attempt to characterize stress as a function of the soil‑reducing conditions. Spectral curves, reflectance peaks, soil moisture observations, and redox potentials were plotted and analyzed to document the conditions of the trees during a two‑and‑a‑half‑month period in the early local growing season. Compared to nonflooded trees, spectral measurements for flooded trees showed elevated reflectance in both the green spectral region at 550 nanometers as well as the near‑infrared region at 770 nanometers. In addition, the reflectance measure‑ ments were strongly related to redox potentials. This illustrates the stressful condi‑ tions that plants experience during flooding due to lack of oxygen for respiration and that have been discussed here by authors. The results indicated that spectrally detectable changes in visible and near‑infra‑ red leaf reflectance may be more influenced by prolonged flooding than saturation. This suggests that when remote sensing is used for wetland mapping, there may be optimal times (Figure 7.31) to spectrally separate stands of forested wetlands during the growing season (Figure 7.32). The work of Ramsey et al., Lunetta et al. and others have shown this to be true. Others have demonstrated how multiple spectra or multispectral remote sensing can enhance studies of general wetlands and adjacent land covers (Place 1985; Gross et al. 1987; May et al. 2002; McCauley and Jenkins 2005; Frohn et al. 2009; Lunetta et al. 2009, 2010), and particularly so with their addition to other data sources, including soils (Federal Interagency Committee for Wetlands Delineation [FICWD] 1989; Soils Conservation Service [SCS] 1992; Anger 2003; Dwivedi et al. 2011),

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FIGURE 7.31  Winter brings its own challenges and advantages. The pinnate drainage pat‑ tern is characteristic when an area has windblown soils and shrub vegetation. The snow‑cov‑ ered farm fields are the light areas in this image of Missouri.

FIGURE 7.32  Low‑altitude images reveal a great deal in a desert area. Juniper trees are darkest. Roads are shadowy light gray. The meandering river is a darker gray. The mottled or spotted looking areas are a mixture of smaller vegetation and dry soils.

hydrology (Mizgalewicz et al. 2003; Ji 2007; Berkowicz 2009), field spectra (Lopez 2006; Lopez et al. 2006), and historical aerial photos or images (Niedzwiedz and Ganske 1991; Barrette et al. 2000; Tiner 2003b; De Roeck et al. 2008). Hyperspectral data are contributing greatly to the capabilities (Hirano et al. 2003; Artigas and Yang 2005; Harken and Sugumaran 2005; Belluco et al. 2006; Zomer et al. 2009; Thenkabail et al. 2011). The convergence of remote sensing experiments such as these holds the promise of understanding complex, spatially disbursed phenomena that govern wetlands.

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RADAR Radar sensors work in the microwave region of the spectrum and have wavelengths that are relatively long compared to the visible and infrared. Commercial sensors generally operate between millimeter wavelengths and 24 centimeters and longer. Radar sensors generate their own microwave wavelength electromagnetic radiation and can be used actively during night or day. Radar provides information that is fundamentally different from sensors that operate in the visible and infrared portions of the electromagnetic spectrum. Due to dielectric constant and surface configuration arguments, radar is sensitive to inunda‑ tion, flooding, and soil saturation as well as salinity conditions. Although the interpretation of radar imagery for civil applications is not as fully developed as that of optical data, radar sensors have many advantages over more traditional optical sensors (Lyon and McCarthy 1981; Wu 1989; Kasischke et al. 1997; Ramsey 1998). As discussed here and other places, characterization of wetland vegetation com‑ munities is also possible with radar and combinations of radar and visual and infra‑ red sensors (Kushwaha et al. 2000; Touzi et al. 2007; Islam et al. 2008). Wetlands such as forested land covers or swamps, shrub‑scrub wetlands, or nonforested wet‑ lands or marshes can be characterized with multiple sensor inputs and at multiple times of the year. This can be done based on land cover characteristics including the presence or absence of woody plants and trees, their abundance or density, and the layering or canopy structure (important in characterizing wetland plants criterion on a vegetative layer dominance test). Lang et al. (2008) have noted that the Wetlands Subcommittee of the Federal Geographic Data Committee (1992, 2009) found that acquiring cloud‑free imagery during the optimal time period was a key obstacle and argued for the utility and value of radar in wetlands work. Lunetta et al. (1999) and others (Ramsey 1995, 1998) have developed multiple date image acquisition and processing procedures to optimize the use of seasonality to identify general wetlands, wetland hydrology and flooding, and forested wetlands. Radar can deliver a number of results that are valuable in the analyses of wet‑ lands. These can include the presence and absence of standing water and saturated soils; the presence and abundance of woody plants and their relative branching pat‑ tern and characteristics; as well as the presence of standing water and moisture con‑ ditions beneath a plant canopy. Sensitivity of radar to water, due to its high dielectric constant, is extremely valuable to the remote sensing of general wetlands. Radar is not only sensitive to soil moisture, but it can also often differentiate between moist soil and standing water using a variety of radar bands and polarizations and their combination (Lyon and McCarthy 1981; Kasischke et al. 1997; Ramsey 1998; Lang et al. 2008; among others). The presence of standing water interacts with the radar signal in a different man‑ ner depending on the dominant vegetation type (Costa et al. 2002; Henderson and Lewis 2008). When the signal interacts with an area of open water without vegeta‑ tion, specular reflection occurs and a dark‑toned area is recorded, as the coherent

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radar light will be re‑irradiated from the antenna and no or a very small signal is observed (Lyon and McCarthy 1981). The radar signal is often dampened in wetlands dominated by emergent or herbaceous vegetation when a layer of water is present (Ramsey 1995, 1998; Kasischke et al. 1997; Wdowinski et al. 2008). Again, specular reflection occurs where a smooth surface reradiates light in an organized fashion in relationship to the source. Polarization aspects of radar can be valuable. The like‑polarization and the dif‑ ferences between C‑HH band (C band or 3cm wavelength radar transmitted horizon‑ tally or H and received horizontally) and C‑VV band have been highly sensitive to flooding (Lang et al. 2008) using airborne sensors. The polarization aspect as well as the dual‑band approach creates the multiple sensor information that is so valuable to analyses. It is also interesting that radar returns often appear bright in tone or high in return in forested wetland areas. This was first identified years ago and much meritorious work has been done to characterize the phenomena and harness its value for analy‑ ses. This is thought to be a combination of functions of water, the vegetation branch‑ ing pattern, and trunk characteristics compared to the radar wavelength or roughness and the corner or dihedral effect of the radar bounced and resulting orientation of receiver or antenna position (e.g., Lyon and McCarthy 1981; Hess et al. 1990, 1995; Ramsey 1995, 1998; Lang et al. 2008). The radar signal is often increased in forested wetlands when standing water is present due to the double‑bounce effect. According to Lang et al. (2008) and others over the years, the double‑bounce result or dihedral/corner return is more notice‑ able in forested wetlands when using L‑band (24 centimeter) radars (Lyon and McCarthy 1979) but can also be seen with C‑band (5.6 centimeters) data (Kasischke et al. 1997, 2003; Ramsey et al. 1998; among others) and X‑band data. Studies conducted with Shuttle Imaging Radar (SIR) ‑C and the Japanese Earth Resources Satellite (JERS) ‑1 L‑HH band imagery have confirmed this finding (Hess et al. 1995; Lang et al. 2008). Many of the first studies applying radar to wetlands and other ecosystems used Seasat imagery and aircraft results (Lyon and McCarthy 1981; Ramsey 1998; Lyon 2001; among others), with an L band horizontal transmission and horizontal receiv‑ ing. This polarity in the use of coherent light allows for different combinations of transmission and reception of radar returns, in essence creating multiple spectra or multispectral imaging. Because materials on the Earth’s surface alter the signal as a function of wavelength and polarity, additional information is obtained by using different bands (i.e., X‑ or C‑band versus L‑band and/or L‑band) and different polari‑ ties, such L-HH versus L‑VH and so forth. This creates multispectral effects that are so useful in analyses. It is also difficult to separate wetland land covers such as fens from sedge/shrubs bogs; these classes cannot be discriminated with optical band sensors and C‑band HH polarization based on theory and on practical experience. Polarimetric information also separates conifer tree bogs from deciduous upland forests under leafy condi‑ tions. This is a roughness argument similar to the case of separating shrub from tree land covers with L‑band radars.

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DATA FUSION Data fusion can provide products that supply much more information than the indi‑ vidual images alone, thereby creating a synergistic effect. These may be fused radar images, a combination of radar and visible and near‑infrared spectral images, and so forth. For example, Ramsey (1998) and Lang et al. (2008) have found that the use of different radar bands such as L‑ and C‑band supplies sensitivity to canopy structure of wetland vegetation communities because of their differential responses to branch‑ ing structure and size. Radar is particularly valuable to separate forest cover from shrub‑dominant cover in upland and wetland areas. The roughness or structural component of the can‑ opy responds greatly to microwaves, and one can discriminate these covers, which at certain times of the growing season may appear to be the same on optical or near‑infrared sensor imagery. A fused image of radar and visible or near‑infrared data can be particularly useful in study and discrimination of general wetlands from upland forested areas, compared to the individual (Ramsey and Rangoonwala 2009) images without fusion images.

CONTINENTAL‑SCALE IMAGE DATA SETS The continental‑scale image data sets are valuable because their content can be loaded into available image processing software. This allows the user to make use of remote sensing data products and tools immediately and learn their utility and value through on‑the‑job training. This is very similar to having the use of Google Earth and Maps and allows gentle entry into this field of endeavor for new users. These advances also allow for regional and continental inventories of land covers including wetlands. The 1990s saw the achievements of continental assessments such as enhanced mosaics of Advanced Very High Resolution Radiometer (AVHRR) data or Earth Resources and Observation and Science or (USGS EROS Data Center Web site), Landsat Multispectral Scanner data (Lunetta et al. 1993) and Thematic Mapper data (D. Shaw et al. 1993), and others (Thenkabail et al. 2000, 2006, 2009; Prigent et al. 2001; Thenkabail 2006). Continental and global coverage have advanced, includ‑ ing GOFCs‑GOLD (http://start.org/programs/gofc‑gold), the Japanese Global Mapping project, and so forth. An early example, the North American Landscape Characterization (NALC) was a pioneering, multiple‑year and ‑agency project to develop current and historical Landsat data sets for evaluation of continental land cover and change in land cover (Lunetta et al. 1993; Lunetta and Elvidge 1998; http://www.epa.gov/mrlc/). It pro‑ vides a good example of how continental‑scale image data sets can useful in regional assessments and how land cover data can assist in regional‑scale analyses (Lunetta et al. 1998). The goals of NALC included developing multispectral scanner (MSS) data for the North American continent, correcting and packaging the data, updating the images in the archive, and analyzing the data sets. The data sets were available as “triplicates” of MSS scenes from the USGS EROS Data Center. A given triplicate contained three Landsat scenes from similar seasons during the epochs of the 1970s (1973 ± one year),

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1980s (1986 ± one year), and 1990s (1991 ± one year). The scenes were produced from the same ground area and with geometric corrections and ground registration of coordi‑ nates. The original radiometric data were provided in the above form using standardized methods (Lunetta et al. 1993). Additional files included DEM data for the scene area and “housekeeping” or metadata files (http://www.epa.gov/nerlesd1/land‑sci/north‑am.htm). Over the years other consortia have been created to address regional‑ and continen‑ tal‑scale issues. This has led to a number of successful efforts in the United States. The NOAA Coastal Change Analysis program (CCAP) has addressed coastal resources and their watersheds (Dobson and Bright 1993) and can be viewed at http://www.csc. noaa.gov/digitalcoast/data/ccapregional/. The USFWS lead consortium has addressed wildlife habitat and land cover of much of the United States with the Gap Analysis Project or GAP (http://www.nbii.gov/portal/server.pt/community/gap_home/1482) and worked with local groups and the USEPA to produce the Southwest GAP (http:// fws‑nmcfwru.nmsu.edu/swregap/HabitatModels/default.htm) and Nevada GAP, for example (http://www.epa.gov/nerlesd1 or http://www.epa.gov/nerlesd1/land‑sci/ pdf/035leb06DB_11x17_Standard.pdf). The U.S. Department of Agriculture U.S. Forest Service has led a consortium to focus on land cover and forest fire fuels for addressing hazards and disasters related to forest and range fires (http://www.landfire. gov/index.php). Perhaps the most well‑known examples of these efforts is the consortium for Multi‑Resolution Land Cover (MRLC), which created over the years the National Land Cover Database the 1990s and for 2001 (http://www.epa.gov/mrlc/nlcd‑2001. html; NLCD 2001) and 2006 (http://www.epa.gov/mrlc/nlcd‑2006.html; NLCD 2006), and the efforts at change detection using these data sets (http://www.epa.gov/ mrlc/change.html). All these efforts can find utility in general wetlands work by providing a regional‑scale look at land covers including wetlands (Prigent et al. 2001). These results can inform on the presence of general wetlands and can be used in display products for reports and other applications. They are particularly amendable to load‑ ing GIS and KML‑based systems for training and analyses. Canada’s wetlands cover about 25% of the country’s landmass and account for nearly 20% of the world’s wetlands. Remote sensing or Earth observation (EO) tech‑ nologies have long been recognized as essential tools for inventory of land covers, and the Canadian government and the Canada Centre for Remote Sensing of Natural Resources Canada is developing such data sets. Groups such as NALC, MRLC/ NLCD (http://www.epa.gov/mrlc/) and other Canadian groups are well known for their outstanding work on continental‑scale mosaic images and land cover thematic maps. Of particular interest are the Laurentian Great Lakes mosaics of Landsat data for the U.S. and Canadian watershed and the forest fire fuels mappings (Guindon, in Lyon et al. [1998] and Lunetta et al. [1998]). Current efforts have been devoted to generating regional‑scale, multiple‑season and multiple‑year data sets from Moderate Resolution Imaging Spetro-radiometer or MODIS data to develop change detection capabilities. Recent work has exam‑ ined corn plantings in the Great Lakes and is moving toward general wetland analy‑ ses over time using the available browser technologies (http://maps6.epa.gov/ami; Lunetta et al. 2008, 2010).

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ADVANCED APPLICATIONS AND PATTERN RECOGNITION Use of pattern recognition and/or computer categorization processes can yield deep information about materials from imagery that goes way beyond the capabilities of human‑driven image interpretation alone (Figure 7.33). These technologies also provide a number of methods to identify, provide location, and characterize general wetlands and their surrounding land covers that greatly influence wetland condition and function. The positioning of these land covers can be operated on with geo‑ spatial technologies as well, to obtain greater information on wetland function and characteristics if desirable. The features can be measured by a given variable or, by implication, functions or processes measures can be based on a secondary measurement or surrogate vari‑ able. This is also the case in using primary measures to infer the actions of an indi‑ rect or secondary measure, which finds great utility in the use of indicators of the

FIGURE 7.33  A suburban area with houses, buildings, roads, natural areas, and waterways is considered a mixed‑use area. Small wetlands are often found in these areas.

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landscape or landscape characterization to feed landscape ecology measures (Lyon 2001; Lunetta and Lyon 2004; Tolcser and Knight 2011).

INDICATORS These same groups are developing Earth observations and indicator‑based methods for mapping wetland indicators required for inventory (http://www.earthobserva‑ tions.org, usgeo.gov). The quality of technology and skills of the interpreters has improved mapping and monitoring of wetlands to a high‑quality level and now the focus is often given to cost‑effective methods and their contribution to identifying, managing, and maintaining wetland resources. A great deal of work has been done over the years to advance the cause of wetlands using spatial technologies. In particular, the leadership of the USEPA’s Environmental Science Division Laboratory has been useful in methods develop‑ ment. This work is available on their Web site (http://www.epa.gov/esd/) and it illustrates great application of GIS, remote sensing, and landscape indicators for understanding environmental impacts and risk to general wetlands (http://www.epa. gov/nerlesd1/land‑sci/lcb/nrb/VFRDB/). The works of Ric Lopez, Ross Lunetta, and associates of the USEPA’s Office of Research and Development (http://www.epa.gov/nerlesd1/land‑sci/pdf/ EPA_600_X‑06_002.pdf) are particularly notable in their insightfulness and use of combinations of advanced remote sensing, GIS, fieldwork, landscape indicators, and accuracy assessment techniques (e.g., Lopez 2006; Lopez et al. 2006; Lunetta et al. 2010). This work also provides an outstanding example as to how to bring together fieldwork, remote sensing, GIS, GPS, and pattern recognition of general wetlands and other land cover types, all to “fuel” models and indicators for analyses and deci‑ sion making. In the U.S. and Canadian Laurentian Great Lakes watershed, a number of us have worked on indicators for some time. In 2008, the Committee on Environmental Quality issued a report on indicators that is favoring their promulgation; the tricky part is making this work over large areas with uniformity and answering a pertinent question. The attraction is, “why can’t we have indicators for the environment and natural resources that mimic the use of economic indicators?” We hope to make indicators a daily or monthly analysis tool and supply answers along with metadata and with uncertainty or error “bars,” so that this approach can be used for informed decision making. In the Great Lakes watershed, we have done this for coastal land cover indicators, energy and transportation issues, and for wetland invasive species (http://www.epa. gov/nerlesd1/land‑sci/default.htm). Researchers at the USEPA (Lunetta et al. 2010) also developed a land cover change detection Web site to look at corn plantings, wetlands, and urbanization on the U.S. and Canadian Great Lakes Watershed. They found increased corn plantings on the U.S. side of the watershed, demonstrating a continental‑scale change in land cover due to policy (Lunetta et al. 2009) using a tool that can be applied by a variety of users. Ric Lopez’s work has brought together field work, remote sensing, GIS, and indi‑ cator modeling to ask general wetlands related questions in a number of locations in

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the United States, including the Laurentian Great Lakes, the White River of Missouri and Arksansas, the lower Mississippi, and East Texas. For example, these analyses are fed data from advanced remote sensing activities in the field and from the sky. Work on Pt. Mouilee and western Lake Erie general wetlands has featured multispectral and hyperspectral imagery (http://www.epa.gov/ nerlesd1/land‑sci/pdf/ptmouillee_25.pdf) and imagery combined with field analyses of Cedar Point and Sandusky Bay (http://www.epa.gov/nerlesd1/land‑sci/pdf/cedar_ point.pdf) and Bay View, Ohio (http://www.epa.gov/nerlesd1/land‑sci/pdf/bayview1. pdf). A historical aerial photo of the same area in 1964 is shown in Lyon (2003) and provides some perspective as to information supplying capabilities of advanced tech‑ nologies. Web browsers have been created to support further work from the resulting datasets and can be found at http://www.epa.gov/nerlesd1. These tools have made use of advanced image processing and data fusion, mul‑ titemporal data collection of moderate and fine resolution, time series analysis and change detection, and pattern recognition and have done so in combination that greatly advanced the technologies and the utility for users (Thenkabail et al. 2011). These bodies of work have been heavily cited and used and are a hallmark of appli‑ cation of remote sensor technologies and have answered policy questions on indica‑ tors and their utility for general wetlands and management queries (Sprecher and Schneider 2000; Lyon 2001; Reddy and DeLaune 2008; Mitsch et al. 2009).

8

Oil and Wetlands

Disasters may be caused by natural Earth processes such as earthquakes, hur‑ ricanes, or tsunamis. Others disasters maybe human induced and are known as environmental or technical disasters (Office of Science and Technology Policy [OSTP] 2006). Disasters are often preceded by hazardous conditions or hazards, and many peo‑ ple prepare for disasters by addressing hazards. This can be accomplished through remediation or through safety and risk assessments to reduce the potential of disas‑ ters and possibly ameliorate their affects. There are many examples of this hazard reduction work worldwide, including efforts on weather, food and water security, and tsunamis events that seek to develop understanding of the issues and hazards before they become disasters (American Society of Mechanical Engineers [ASME] 2008; Thenkabail et al. 2009). An important aspect of a disaster is the assessment of damages. These assess‑ ments are necessary for a variety of reasons (Huadong 2010). They may include iden‑ tification of the presence or absence of damages and estimated losses, prioritization of humanitarian aid and cleanup, and so forth. In the case of environmental disasters it is important to act in assigning responsibility to parties, assessing potential risk and risk mediation, and supplying evidentiary needs for litigation (Group on Earth Observations [GEO], http://www.earthobservations.org). A parallel issue is the extent of damage and monitoring of remediation to make the environment and ecosystems safe and the people “whole.” How can we repair and remediate natural or human‑induced damages without addressing needs, inven‑ tory, and supply and applying resources through triage? In the case of environmental or technical disasters there is precedent in determin‑ ing and assessing damages to potentially responsible parties and to engage these parties along the way to address cleanup goals even in the midst of the disaster and remediation.

OIL SPILLS AND HAZARDOUS WASTE A number of remote sensor and geographic information system (GIS) technologies have been used in the identification, characterization, and management of oil and chemical spills and hazardous waste sites (Lyon 1987; Garofalo 2003). Often the use of remote sensor technologies helps to identify potential problems or hazards and educates the user as to the prevailing conditions of the feature or landscape in rapid fashion (Lyon 2001). These technological methods can also be generalized in their application to issues related to identification, risk or damage assessments, and mitigation of these harms (Institute of Medicine 2010).

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OILING AND METHODOLOGIES The Gulf of Mexico oiling issue comes about a year after the last of the litigation was resolved from the 1989 Exxon Valdez spill and cleanup. These types of large disas‑ ters take on a life of their own. The issue can be in the public eye long after the actual event, such as the World Trade Center disaster (http://www.epa.gov/wtc/panel/pdfs/ WTC‑EPIC‑Text‑draft.pdf). The path of the efforts takes on a face that can be very different in reality as compared to public perceptions. So it is also true with research and operations driven by oil spills. Much of the research on tracking the transport and identifying oiled areas began with the Santa Barbara spills of 1969. Over the years, spill technologies have been researched and tested on a variety of events from small harbor or bay losses to larger examples such as Exxon Valdez. The methods are developed and tend to become dormant once the dialogue is finished. Ten or more years later, it all becomes topical again with a large‑scale event. This happens a great deal in science. One develops some great techniques and methods to address a certain problem. The problems are “solved” and the dialogue moves on. The old saying is a good idea does not become good again until 6 to 10 years after the last piece of work is published. Then the ideas “bloom” or rise as a Phoenix. So too is the case of the oil spill issue. There also is the question of scale. The largest spills are rare and the focus natu‑ rally is on cleaning up, not on research. In the meantime, were the methods codi‑ fied, the technologies engineering into operational tools, and the people trained and equipment deployed? Sure, but for smaller events, which are more common or frequent. Over the years, there was a certain amount of work done on large‑scale solutions in the aftermath of Exxon Valdez. But a great deal focused on the operational aspects of cleanup and the actual cleanup. The advent of hurricanes Katrina and Rita has also witnessed some development and great work done with spills of petrocarbons and hazardous wastes as well as solid waste issues. All these disasters have seen the advance of oil detection and wet‑ land monitoring capabilities and in particular those of remote sensing and GIS.

WETLANDS AND OIL There is a lot of interest in the identification of wetlands that have been inundated with oil. This has to do with the dispersive nature of oil and its components, the dif‑ ficulty in addressing fate and transport, and the location and impact of the oil. It is necessary to identify, map, and determine wetland‑type information in planning and management and, in this case, for remediation. Remote sensor tech‑ nologies such as aerial photographs, airborne and space‑borne sensor data, as well as allied products such topographic maps, engineering‑style maps, and GIS prod‑ ucts offer this capability. These tools are vital for documenting size and loca‑ tion of wetlands and for determination of damage and for addressing remediation (USACE 1987; K. Lee and Lunetta 1995; C. Lee and Marsh 1995; Williams and Lyon 1997; Lyon 2001).

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SPECTRA The presence of oil or hazardous chemicals changes the makeup of the spectral signa‑ tures of wetlands, complex as they are already without oil’s contribution (Thenkabail et al. 2011). It is the deviation from the norm, the unique spectral characteristics of oil, and the influence of oil components on wetlands that make its presence detectable. Crude oil has a number of chemical components. Many of these components, and in particular the refractory or very stable components, are subject to slow decompo‑ sition. Some components are volatile and are soon evaporated. The volatiles often move from the aqueous environment to become an atmospheric problem or can be absorbed or ingested and become a component of the body‑burden of animals if they survive the exposure. There has been discussion in previous chapters about the spectral and spatial characteristics of wetlands. These are naturally diverse in spectral information due to the mixture of soil, water, and plants materials and their juxtaposition across the landscape. This makes them difficult to identify spectrally, because they look like other mixtures of these materials but different from upland or terrestrial land covers. In the case of oiled wetlands, one should look for diagnostic characteristics such as the following:

1. Dark‑toned clumps. For detection purposes, residual oil components that wash onto shore and into wetland areas are spectrally dark toned or colored in the visible spectrum. We see these on images of oiled areas as dark‑toned areas or clumps and various dark tones or colors running from deep black to red‑brown. In coastal and wetland areas, they can be confused in the visible by other dark materials such as organic matter, organic soils, and submer‑ gent plant beds. (Not surprisingly when buried millions of years ago under temperature and pressure, wetlands and similar organic materials were con‑ verted into now dark-toned oil, gas, and coal.) 2. Plants with lower chlorophyll levels or dead plants. The oil and component hazardous chemicals of crude oil also stress and kill the plants found in wetlands, as well as other biota. This will alter the spectra of plant materials over time, particularly that of chlorophyll, in what may have been healthy, leafy biomass. The spectra of plants in the visible and infrared are well known and quite different in response from other materials such as water or soils. These differences can be used to determine the presence or absence of oily materials and their effects on the health of plants. Simply, the death of plants and loss of chlorophyll and its characteristic reflectance cause plants to appear spectrally dead, with an increase in red reflectance and decrease in the near‑infrared reflectance. This plus the dark tone or low reflectance of oiled materials provides a distinct spectral signature to identify oiled areas with dead or dying plants. The spectra of dead plants, or plant residue, is in itself very different from that of oil or oil that has been exposed to the elements or weathered oil. Plant residue over time with its loss of chlorophyll and chlorophyll spectra

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takes on a flatter spectral curve and appears much like soil in spectral curve shape or in freshwater areas like that of soil suspended in water. 3. Mixed spectra. Much has been said of the mix of materials and resulting spectra of wetlands in chapters here. Oil adds to that mix spectrally and spatially. One needs to search out the contribution to the spectra from oil. One also needs to think and search for the juxtaposition of oil. Because water carries the pollutant up into the wetlands it may be distributed based on the actions of water. In some cases the oil is only found on the periphery of the wetlands where it has been transported by water. Oil mixed with plants, water, and soils will initially be found at the base of the marsh and can be obscured by the canopy of the marsh. Temporally, the oil killing affects may not have advanced and again the plants may have an abundance of chlorophyll. Hence, there is clearly a spectral distinc‑ tion but also a spatial and temporal distinction. These differences can be learned and the influence and distribution of oiled wetlands can be followed remotely.

WATER QUALITY ISSUES AND OILING Water quality characteristics can be nicely measured from remote sensor technolo‑ gies (Butera 1983; Bukata et al. 1987, 1995). Water is fairly transparent and absorb‑ ing, and as such it will exhibit characteristics of the materials that are dissolved or suspended in the water. This makes the surficial identification and measurement of concentrations of oil or hazardous chemical materials somewhat straightforward (Lyon et al. 1988). Tracking of surface transport of oil can assist in identifying pos‑ sible landfalls and potential oiling of wetlands. Compared to many terrestrial applications, water, or seawater, specifically is a three‑dimensional material and complicated by differential water depth penetration, extinction, and re–reflectance (Svejkovsky and Muskat 2006, 2009). A number of variables in water have proven to be measureable by remote sensor technologies typi‑ cally in combination with surface and volume sampling. Some water quality variables are measured directly and demonstrate a very good linear response of light reflec‑ tance or absorbance to concentration of the variable, and others must be modeled to understand their transport, possible transformation, and distribution in the water column. There is a literature of the transport by water of oily materials. This has been developed to predict the movement and sometimes the concentration or volume of oiled waters (Lyon et al. 1994; Advanced Resources International 2001). This is thought to be helpful in identifying the trajectory and velocity of oily water move‑ ments and the need for mitigation or cleanup activities. It can also be useful in triag‑ ing distribution of resources and tracking remediation. Water often contains sediment in freshwater systems and phytoplankton in all systems. Surface‑suspended sediment concentrations can be measured in a linear fashion over concentrations from 0 to 25 mg/L to as much as 600 mg/L plus in fresh‑ water. Chlorophyll a also shows good linear responses in concentrations of less than 1 mg/L to more than 25 mg/L and upward depending on freshwater clarity.

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The addition of materials into water results in a reflectance change from the unaltered water body that is a composite of the individual materials. Water that holds nonpoint materials such as oil components and/or high concentrations of other pigments can be evaluated quantitatively using a combination of on‑site sampling and remote sensor analyses (e.g., Lyon et al. 1988; Fingas and Brown 2000; Lyon 2003) and modeling. This is further complicated by the use of dispersants, which cause surface oiling effects to be submerged and become part of the water column.

OIL APPLICATIONS OF GIS The problems associated with nonpoint sources of pollution such as oil can be addressed with remote sensor and GIS technologies. The utility of the data and tech‑ nologies is due to the size and distribution of the problem; the need for quantitative assessments or inventory of resources to manage and remediate; and the widespread distribution of the problem. The capabilities make remote sensor and GIS approaches of great value compared to localized, traditional measures that are important and should be used but by their intensity and localized application are challenged by the two‑dimensional and three‑dimensional characteristics of the problem. GIS technologies allow a number of products to be created and models to be run in support of hydrological and wetland applications. Products include digital files and hardcopy image maps of single variables, variable combinations, thematic maps of drainage and watershed variables, and similar simple products. Three‑dimensional or volumetric displays can also be made of pollutants and position and concentra‑ tions in the water column. Also, these products help to integrate variables that are important to distribution of infrastructure for remediation. GIS technologies can greatly facilitate the storage and analysis of measurements, as described here and in other sources. Many water quality and disaster damage data sets have been developed over the years and perhaps in a number of data col‑ lection campaigns. The differences in sampling can be characterized with attribute entries in GIS files and different layers in the GIS. The sampling points maintain their unique characteristics and information yet they can then be evaluated with GIS technologies for such analyses as before and after the event and monitoring of cleanup. This was useful in tracking sampling for Katrina/Rita events (USEPA 2005; http://www.epa.gov/oem/docs/oil/fss/fss06/roper_3.pdf) for early surface water sam‑ pling in New Orleans and other places. Complex issues can be addressed by developing products to present results of statistical or deterministic models. These products could include visualizations of wetland oiling remediation scenarios; land cover and land use change maps; com‑ bining tabular results of statistical analyses with displays for analyses; presenting results of model simulations; and monitoring remediation and posting tabular and image results. Data fusion techniques are particularly helpful for oiling analyses and modeling. The combination of visible and near‑infrared imagery and radar data can be very valuable. For example, the European, Japanese, or Canadian RADARSAT radar sat‑ ellite systems have unique polarimetric and all‑weather capabilities and supply many of the capabilities unique to radar systems in support of wetland efforts. Space‑borne

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RADARSAT and airborne radar systems data can be a primary and cost‑effective source of information for mapping and monitoring wetlands and the influence of oil (Lyon 1987, 2003; Salem et al. 2005; Jha et al. 2008). Ramsey has worked in many of these areas of wetland characteristics and remote sensing. He and his associates have provided excellent examples of wetland detection and monitoring and assessment capabilities with data fusion, as well as use of visible, near‑infrared, and polarimetric radar as fusion sources of data (Ramsey and Jensen 1990, 1995, 1996; Ramsey and Rangoonwala 2009). This and other applications show how data fusion can help in the identification of wetlands from upland land covers. These technologies can help with identi‑ fication in poor weather and can help parse oiled wetlands from undisturbed coastal wetlands.

9

Permitting, Field Inspection, and Jurisdiction

The delineator must function as per instructions and guidance from the scientific and engineering community and use the regulatory guidance provided by the U.S. Army Corps of Engineers (USACE) and any other agencies involved. One must function in an objective fashion and produce a delineation and report that meets the needs of regulatory entities who administer wetland regulations and permitting activities. It is also important to best represent the needs and rights of the landowner or client in developing the report and presenting results for inspection. One reason that delineations can be difficult to perform is the variety of disci‑ plines and knowledge that go into the activity. Contemplate the skills and experience necessary for doing any of the following: Identifying rare grass species correctly; visually estimating plant dominance in multiple vegetative layers; identifying subtle mottling patterns in soils; laying down a wetland boundary and mapping it for a report; and interacting with clients and regulators. Clearly, these are just the sort of variety in skills that make delineation challeng‑ ing. The varieties of education and experience necessary to do this sort of work make it difficult. Hence, companies or groups often use teams of people with different skills to address this diversity of tasks.

THE PERMITTING PROCESS Once the wetland delineation is made and its conclusions are known, it is possible to evaluate the need for a permit. Currently, whenever jurisdictional wetlands are present on a property, and the intent of the owner is to fill some of those wetlands, it is desirable to obtain a wetland delineation and report and to determine whether a permit is necessary. In general terms, the current situation necessitates applying for a permit when there is a proposed discharge into a jurisdictional wetland of a given size according to per‑ mitting criterion. A variety of tests need be performed when a discharge is contem‑ plated. It is also necessary in general to determine the sources of water for the wetland area and the connectivity of the water sources. This all has to do with the prevailing criteria for discharges as administered under Section 404 and 401 of the Clean Water Act (CWA) and/or the Rivers and Harbors Act in the case of navigable waters of the United States and other prevailing local or regional requirements and/or laws, statutes, or rules. 157

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The discharge may be allowed in some form under prevailing requirements, under nationwide permits or an individual permit, or the area may fall outside of current jurisdiction (http://www.usace.army.mil/CECW/Documents/cecwo/reg/nwp/ nwp2007_gen_conditions_def.pdf). The permitting process and types of permits are described on the USACE Wilmington District Web site (http://www.saw.usace.army. mil/wetlands/permit_primer.html#Types of Permits) and other district or headquar‑ ters site (www.usace.army.mil/CECW/pages/cecwo_reg.aspx). Prevailing conditions and/or interpretation may allow discharge up a certain quantity or into an area in size, for certain reasons, and/or if the area is above the headwaters of the water drainage system or based on characteristics of water connectivity. This is based on interpretations of nationwide permit and/or individual permit results as determined by the USACE. This also assumes that the discharge does not violate other environ‑ mental conditions including state water quality certifications under Section 401 of the CWA (http://www.saw.usace.army.mil/wetlands/permit_primer.html#Types of Permits). The variety of nationwide permits from 2007 is detailed at http://www.usace. army.mil/CECW/Documents/cecwo/reg/nwp/nwp2007_gen_conditions_def.pdf. Their utility is complex and likely localized in the appropriate application in a given part of the United States. Hence, again the need for expertise as to the application of a nationwide permit can be subject to local and regional interpretations. The “headwaters” or isolated wetlands issue is defined in a number of ways as the permitting or laws have been interpreted over time. It is vital to understand the current conditions as to laws, regulations, and statutes in going about wetland issues and certainly as actions relate to discharges and water quality and water connectiv‑ ity issues. A permitting action can be much more complex if a fill or discharge is contem‑ plated in areas of sensitive resources. If a wetland is found in tidewater or coastal areas, if it contains unusual plant or animal species such as federal or state threat‑ ened or endangered species, or if it is below the headwaters of the watershed and/or in navigable water, the regulatory condition can change in complexity. An example is the applicability of the Coastal Zone Management Act in U.S. coastal and Great Lakes waters. Once the need for a permit has been determined, the Army Corps of Engineers can be contacted. This contact can be best made through the USACE district that has jurisdictional for the area under study. The contact is generally the Regulatory Functions Branch or similar branch of the district. USACE contacts are available at http://www.usace.army.mil/ContactUs/Pages/default.aspx. The initiation of discussion with USACE will require information. This entails conversations or correspondence related to the presence of wetlands on the prop‑ erty and the intentions of the landowners concerning any change in land cover that departs from the current wetland condition. Hence, a necessary part of the permit process is a wetland delineation and report to be able to discuss the wetland condi‑ tions from a position of knowledge. As part of this process, the USACE will likely visit the property. This can be accomplished in company with the landowner and/or the author of the wetland delineation report and perhaps an attorney for the landowner. USACE will examine

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the condition of the property, look for wetland indicators, and provide information related to the proposed permit. If the wetland report is available, they will examine the adequacy and quality of the report and delineation in the field. If the report is available, they can either agree with the wetland delineation and report or suggest revisions that are deemed necessary. If the wetland boundaries are flagged and perhaps surveyed, they can inspect the boundaries in the field. After field visits and office work, the report and permit application can be acted upon. A revised delineation report may also be submitted for review in the process. If the report largely represents the consensus of the USACE and the landowner, as presented by the landowner or a designated agent, a permitting action or other action may be pursued. The simplest solution to the permitting matter is to seek consensus with the USACE concerning the presence and location of jurisdictional wetlands. There are few simple remedies for a disagreement between the landowner and the USACE, though some approaches are discussed in Ward (1992) and other sources. To save time and achieve a good resolution, it is best to iterate to a solution that is agreeable to the landowner and to the USACE. For information on permitting activities, go to http://www.usace. army.mil/CECW/Pages/cecwo_reg.aspx or other USACE Web sites. Oftentimes, the delineator and the USACE have findings of jurisdictional wetlands on the site. A very good solution to an impasse on location and quantity of wetlands is to avoid disturbing the wetland resource. This is accomplished by redesign of the site plan to avoid or reduce fill in jurisdictional wetlands. This allows the landowner to avoid the issue of mitigating filled wetlands entirely by reducing the fill in juris‑ dictional wetlands or eliminating the fill or discharge. The action also necessitates protection of the wetland resource from impacts related to adjacent development. Commonly, the optimal course of action is to build around a wetland. This neces‑ sitates development of an engineering plan after the location and size of the wetlands have been determined. Though this makes sense logically, it can be difficult to do “late in the game.” Hence, knowledge of wetlands and other permitting or National Environmental Policy Act (NEPA) 42 U.S.C. 4321 et seq. issues is necessary early in any project to allow for flexibility in site planning. Again, there is a need for a wetland delineation and report to guide the planning of the site or management of the resource. This effort should be completed early in the process of property acquisition and development and, if possible, it should pre‑ cede or be in parallel with the engineering design phase of the project.

CONNECTIVITY An important aspect of permitting is the location and the connectivity of water con‑ veyances. Currently, all meanderings of water moving downhill are of interest pro‑ grammatically to some parties. This emphasis is a direct result of rulemaking and litigation over the past decades. We all need ways to understand the pathways or drainage of water across the landscape, from headwaters to the seas, and to be able to identify and map water

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conveyances and water boundaries. It now remains and is incumbent upon us to harness these technologies to locate, measure, and characterize wetlands as well to identify and document the water connectivity and conveyances that occasion their presence and their persistence and their jurisdictional qualities. Yet it is the questions of laying a boundary on waters, their separation into defi‑ nitional entities, and the wetland hydrological criteria that receives a great deal of attention. Hence, methods to measure those criteria and water conveyances are important here in questions of permitting activities (Garbricht and Martz 1993; Martz and Garbrecht 2003; ESRI 2007). Here we offer a variety of methods to identify and characterize wetlands and methods to locate small to very small water conveyances. This is an attempt to meet that particular need of locating and characterizing water conveyance and wetlands as to possible jurisdiction, which is compelling in modern debate. These methods also can be useful as a compilation of techniques that have been established and tested (Jenson and Dominque 1988; Lyon 2001). These can be help‑ ful in characterizing a given site or when an unusual set of conditions is present or disturbance has rendered characteristics necessary for delineation to be absent. These methods and techniques have been worked out by a variety of practitio‑ ners (Lyon 2001, 2003; Ozesmi and Bauer 2002). The USACE has been particu‑ larly active with studies by their headquarters and field units or districts and in their research programs and laboratories (USACE 2008a–e, 2009a–b, 2010a–f). Other groups have developed water conveyance mapping technologies that can locate the water sources and pathways, map and store the hierarchy of flow, store adjudication decisions as to location and provide information on precedents, and so forth (Lyon 2001; Maidment and Djokic 2000; Maidment 2002; ESRI 2007). These mapping or locational technologies have merit in themselves in identifying and characterizing wetlands. This can be done over large areas to conduct invento‑ ries and to manage resources and can be done locally in support of the obvious case of permitting. As simply explained, one can use these geographic information system (GIS) watershed drainage identification and mapping technologies to identify the drain‑ age pattern or connectivity of a watershed. One can work from available mapping information, but engineering‑style topographic maps in digital form are ideal due to their scale and they are generally available for Earth moving and cut‑and‑fill calcula‑ tions on a site (American Society of Photogrammetry and Remote Sensing [ASPRS 1990]; USACE 1993; Falkner and Morgan 2001). From such a product, the drainage ways can be identified and connected and mapped. From GIS and mapping analyses the sources of water and drainage can be identified high up in the watershed or into the headwaters. The resulting digital connectivity product can be interpreted or subject to digital analyses. It can be “draped” over imagery to provide an image view with drain‑ age. A three‑dimensional perspective can be developed using the topographic map product or digital elevation model, and this can greatly facilitate interpretations of drainage (Argialas et al. 1988; Lyon 2001; Maidment 2002). These products can be checked for accuracy and precision in the field and through remote sensor data analy‑ ses (Stevens and Jensen 2007; Congalton and Green 2008; Lunetta and Lyon 2004).

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Using resulting products from analyses and field inspections, it is possible to iden‑ tify connectivity and determine likely jurisdictional boundaries for waters (Ji and Mitchell 1995; Ji 2007). One can then determine connectivity along the drainage way up into the headwaters and determine whether wetlands are isolated, adjacent, or connected hydrologically, and so forth and map their position to larger down‑ stream waters such as waters of the United States or navigable waters.

JURISDICTION A real and valuable asset of these technologies can be at the forefront of the debate in the wetlands arena. Knowing and tracking the conditions of water conveyances helps one to understand the supply of water to wetlands and to understand the sources of the hydrological criterion. Important to current debates are the identification and location of the water con‑ veyance and how they fit into the legal definitions that drives jurisdiction. Herein lies a great value of these techniques, because if applied correctly, and the knowledge maintained, the characteristics can be used as another aid to sort through the juris‑ dictional questions and make clear the present state. To address jurisdiction and boundary issues requires a mix of technologies along with fieldwork. Typically, the conveyances of water bodies of large sizes are well understood and documented scientifically, engineering‑wise, and legally. These are rivers and streams. This is a result of many years of working in and around these resources or in or on them in the form of navigation, recreation, and commerce. Even the middle‑sized water resources are characterized due to the nature of the work. Feature agricultural areas where drainage and irrigation have been studied and management approaches have been used and improved over the years. These are known as creeks and gullies, yet the various other names used locally portend the variability in knowledge bases and the local flavor of the usage and knowl‑ edge. Picture other names such as creck, coulee, draw, bayou, run, arroyo, and/or third‑degree tributary. The small to the very small features of the water course are known scientifically and to a certain extent by the landowner or land steward or, for that matter, local experts such as river‑keepers or water sports enthusiasts. They are often beneath the minimum mapping unit of mapping exercises or beyond the jurisdiction of national, regional, or local management entities and are basically “off the charts” to most folks. Yet they are the nexus of the arguments about jurisdiction in wetland issues and now require the documentation of the knowledge that heretofore was unneces‑ sary from a regional perspective. Traditionally, regional or national management resources have been brought to bear to understand, document, codify, and manage these resources. This works fine for the grand look or for medium‑sized regional understandings. On collecting details on smaller features or on a more detailed level, this organized approach is avoided due to cost, lack of need, issues of privacy, and so forth. Yet, here is where we find the jurisdictional questions and here is where there is no or little site‑specific information for permit findings or permit oversight.

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Hence, it is valuable and useful to use mapping technologies and remote sensing to both identify wetlands and to characterize the water conveyances that occasion the wetland and those that are connecting or adjacent to, and to characterize them as to jurisdiction (Lyon 2001; Maidment and Djokic 2000; Maidment 2002).

PERMITTING AND ENVIRONMENTAL ATTORNEYS Many questions related to wetlands are mostly legal questions. The people involved in delineation understand laws and regulations from a lay viewpoint and are able to comply with the applicable legal requirements. As is the case in many legal mat‑ ters related to wetlands, it is often necessary to seek the assistance of a specialist or environmental attorney. A 404 wetland permit evaluation by the USACE is designed to be done by the landowner or a designated engineer or wetland expert working for the landowner. However, the complexities of the law, government administration, as well as sci‑ ence and engineering are such that it is very wise to involve attorneys familiar with wetland issues. From the landowner’s perspective, the potential costs associated with a work stop‑ page via a site replanning, a cease‑and‑desist order, or a redesign of the constructed project argue for addressing wetlands in a direct, highly organized fashion early on. Errors can be costly, and all parties involved wish to avoid errors, many of which can be related to legal questions. Environmental attorneys can often solve problems associated with USACE permitting and focus resources on answering the questions in a germane and precise fashion that results in a consensus position. It is also hard to understand the subtleties in identifying water resources of the United States and the current local, regional, and national interpretations. The advent of the Supreme Court decision and the potential of Clean Water Restoration Act debate argues for using very knowledgeable people in activities of this nature. It is also good to note that a scientific and engineering‑based delineation and wetland report is a necessary first step in a wetland analysis, and an attorney will eventually require this information for guidance purposes and for forming replies to the USACE’s questions related to permits if he/she is representing the landowner. Permitting itself can also be complex in determining which type of permits to use, whether nationwide permits are applicable, and prevailing water quality certification issues. Individual permits can be complex or become complex and assistance will likely be needed. For information on permitting activities, go to the state of interest and address the water quality certification issues and/or visit http://www.usace.army. mil/CECW/Pages/nw_permits.aspx or www.epa.gov for more guidance.

WETLANDS AND RIPARIAN AND RIVERINE AREAS Many times work is being contemplated in or around riverine areas. It is important to note that laypeople often consider all riverine features to be wetlands or wetland like. This is not generally true, because many of these areas are well drained during the growing season and do not exhibit anaerobic soils conditions throughout the soil horizon yet have many of the wetland‑loving plants we generally recognize (Ainslie

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et al. 1999). The fact that many plants reside in riverine areas and in wetlands is con‑ templated by the various levels in the National Plant List (Reed 1988). Riparian areas are commonly flooded during spring runoff conditions and condi‑ tions of storm flow (U.S. Department of the Interior [USDI] 2003). Both are tem‑ poral in nature and usually do not create longer‑term anaerobic conditions. Often flooding in spring occurs when deciduous plants are still dormant from winter, and effectively the plants “dodge” the harsh conditions of lack of oxygen for respiration by being in this dormant or low‑metabolic condition. These plants and their adapta‑ tions allow them to “duck” or avoid the harsh period of flooding. Riverine areas without wetlands hold many valuable traits and naturally are rec‑ ognized for those traits by ecologists, conservationalists, and sports enthusiasts and by the regulatory environment. Hence, when working in or around riverine areas one must be cognizant of the regulatory requirements of these environments along with those of wetland areas that may be found there. Each system is different functionally and in regulatory and permitting matters. In addition, the presence of a riverine system or feature begs questions of regula‑ tory identity or the identification of regulatory boundaries. Additional considerations on working in riverine areas can include handling of large woody material from unsalvageable riparian vegetation that may be preserved or used as aquatic habitat features; implementation of best management practices (BMPs) to minimize any effects of trafficking or equipment on soil or vegetation to halt or minimize erosion or sedimentation; and the avoidance of disturbing vegetation during construction and revegetation for stabilization and for wildlife habitat upon completion. These actions include those contemplated by Executive Order 11988, Floodplain Management Compliance, which directs all federal agencies approving or imple‑ menting a project to consider the effects that the project may have on floodplains and flood risks. The project needs to be designed to not increase the frequency or likeli‑ hood of flooding in nearby developed areas. Flood elevations should not increase as a result of the project. In addition, there is Executive Order 11990, Wetlands Protection, which directs all federal agencies to minimize the destruction, loss, or degradation of wetlands and to preserve and enhance the natural and beneficial val‑ ues of wetlands. The project should not result in the destruction, loss, or degradation of wetlands. It is desirable that wetland areas may increase as a result of the proj‑ ect. Clearly, operating in riverine systems necessitates a look at a variety of issues beyond the focus of jurisdictional wetlands.

MITIGATION In some projects the alternative to avoiding wetlands or small nationwide permit actions is an individual permit. The subsequent requirement is often to mitigate the action by constructing new wetlands on a less “central” part of the site or participat‑ ing in a mitigation project or bank. The wetlands can only be legally removed after the permitting process is completed and a mitigation approach or plan has been accepted by the USACE and other interested agencies. The practice of mitigation through constructed wetlands is both costly and con‑ troversial, and there is a large literature on the subject and on the construction and

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operation of mitigation wetlands. Mitigation projects are accompanied by many requirements related to wetland characteristics and functions, permitting activities, and legal issues. One requirement is that similar habitat in function and quality is built and main‑ tained over a long period of time. Mitigation is a serious exercise in engineering and wetland management and assessment of function (Schroeder 1996a, 1996b; Clairain 2002; Klimas et al. 2004, 2005, 2008a, 2008b). Often, an initial milestone used to evaluate the quality of a mitigation effort is that the constructed wetland displays a variety of wetland functions that were present in the original, mitigated wetlands (Brinson 1993; R. Smith 1993, 2001; Brinson et al. 1995; Evans and Allen 1995; D. Smith et al. 1995; Walton et al. 1995; Shafer and Yozzo 1998; R. Smith and Wakeley 2001; Shafer et al. 2002, 2007, 2008; R. Smith and Klimas 2002). Moreover, the function should be maintained over a long period, say 5 years or more (Nestler and Long 1994, 1997; Sprecher and Schneider 2000; Lin 2006; Lin et al. 2006; Cole et al. 2007). The implication is that it should function for a long time, because the habitat it replaced was the result of many years of certain wetland conditions (Johnston 1994; Dibble et al. 1995), and that the function be maintained and measureable in different ecosystems and regions (Wakeley and Smith 2001; Nobel et al. 2002, 2004, 2005, 2007; Rheinhardt et al. 2002; Wakeley 2002; Wilder and Roberts 2002; Shuman and Ambrose 2003; Uranowski et al. 2003; Stutheit et al. 2004; Vidon and Smith 2008). There is a great controversy concerning whether mitigation wetlands have suc‑ ceeded in duplicating or approximating the original conditions of the mitigated wet‑ lands (Walbridge 1993; Falkner and Poach 1996; Washington State Department of Transportation [WSDT] 2008). Though mitigation banks have been in existence for some time, this is a continuing source of discussion and the entire process is sub‑ ject to future change. This change will be likely due to the controversy and due to increased research yielding detailed findings as to success based on functional char‑ acteristics and duration of function of constructed wetlands. The myriad scientific and engineering research that has been done is a mark of how people are trying to understand the results of these efforts and to feed the dialogue with facts. Clearly, the effort that can be involved in mitigation is great and the potential costs can be high. It is more expedient and simpler to avoid the jurisdictional wet‑ lands and build adjacent to them or at some other location. This will preserve the resource and save time and money in the long term. The practices of avoiding wetlands or discharging into wetlands and/or mitigat‑ ing the damage require a wetland evaluation to be conducted. It is an important first step and part of the work to be completed in any site planning or development effort. Much as a developer, planner, or engineer would evaluate a site for buried gasoline tanks, hazardous wastes, floodplain areas, land ownership and titles, and other conditions that could interfere with development, each site must be evaluated for wetland resources. Mitigation is sometimes necessary when the presence of the wetland will hinder use of the property. The issue of mitigation of wetlands is a difficult and complex one. The scope is beyond this effort. Interested parties can refer to other books on the subject for guidance (Salvensen 1990; Hammer 1992; Mitsch and Gosselink 2007; Kadlec and Wallace 2009).

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THE REPORT AND PERMITTING In using these methods and techniques, it is important to remember a number of things. The permitting activity typically is qualitative both in the data gathering and reporting, as well as in the adjudication of the permit. On one hand, the quality and amount of the qualitative information going in to the permit can bolster the finding. On the other hand, the permit is not a scientific or engineering experiment. Too much information can potentially obscure the result or compromise the result through a wealth of detail that may not completely document the case for the needs of a permitting decision. Should these activities be subject to legal action, this wealth of information may be useful. Or it could bamboozle the judge and/or jury or lead to intellectual discourse perhaps unfamiliar to both entities or result in the “battle of the experts.” The old adage of the “right tool for the job” comes into mind and frequently comes into play because it focuses the report on the result or outcome. Naturally, there are times when more detail is required, and this can be supplied by the advanced methods and techniques provided here. This occurs when the wet‑ land conditions are problematic, various indicators are missing due to site conditions or disturbance, or when the permitting group requests more detail. The focus should be to supply enough detail that the wetland or upland and its extent can be demon‑ strated and recorded in documents and graphics, so that the permit can be approved with confidence and within the time allotted. What are the elements of a good permit report? The wetland and upland resources should be well characterized according to the wetland criteria. The finding at each sampling location or point should be well documented, and the sample point should be recovered in the field during inspection to validate the work and its documenta‑ tion via the field conditions. Much later, if a controversy “brews,” it is a comfort to the regulators and to the landowner to have a well‑executed report. The wetland boundary should be made evident on the site. This can be accom‑ plished by marking the boundary in the field using flagging tape, wands, or a combi‑ nation as described earlier. This wetland boundary should be mapped onto a mapping base and provided in the report and for field inspection of the mapped boundary.

OVERSIGHT One of the authors worked for some time in the USEPA and in the USACE. The gentle reader might assume that the author would know something about the goings on in the USEPA’s Office of Water (OW) and in the USACE. Though the USEPA is often many things to many people, it is a regulatory agency and much is held on close hold. Still by astute reading of “tea leaves” and crystal balls and detailed reading of documents (http://www.insideepa.com), one may garner some knowledge beyond Web site information as to how OW and OW people in the regional offices conduct their oversight of USACE permits. According to legend, once the USACE district office has received and processed an application for a wetland permit, the application itself (without supporting docu‑ ments such as the landowner’s report to the USACE, again, according to legend) is elevated to the USEPA regional office for review. That group has some period of time

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to do its oversight and to pass on the permit document from the USACE. According to legend, if there is an issue or two, the permit needs to be halted by a USEPA authority. This may be in practice the regional administrator for the USEPA region. The USEPA oversight group will often examine the presence of nearby adjudica‑ tions; the presence or absence of rare or endangered plants, invertebrates, or ver‑ tebrates species; water conveyances and their jurisdictional components as per the current guidance; and so forth. A good way to learn about the USEPA’s approximately 13 program offices and 10 regions is to read “Inside EPA,” as do many people in the EPA to learn about the goings on at the agency (http://www.insideepa.gov).

INSPECTIONS An important part of most permitting activities is some sort of on‑site inspection. This serves several purposes. In earlier chapters, the reader was urged to walk the entire site and, if possible, do so several times. This goes to good practice and makes sure that one is not surprised by a feature that went unnoticed in earlier efforts. Certainly, one does not want the regulators to find something that is not sampled and made known in the report. Or worse, the area is subsequently recognized as being a wetland as opposed to an upland or riparian area, etc. Though not often true, many times in a given region the same delineators meet up with the same regulators. Contrary to popular notion, regulators often have memories and talk among them‑ selves and often take notes and share them with like‑type regulators. One delineator remembers a very, very large property composed of agricultural fields, hardwood forests, and riparian areas. During a very hot summer period, of great humidity and ample bugs and poisonous flora, that delineator walked the site for days on end looking at every nook and cranny for the elusive jurisdictional wet‑ lands. Some isolated examples were found and incorporated into the site plan for preservation. Of particular note was a feature hidden deep in the hardwood forests by topography and by leafy and woody foliage. From a few feet away, the feature was hidden. After crashing through the woods and being torn by blackberry briars for days on end the feature was revealed. It was a several‑acre, pit hole, high‑pH bog or fen complemented by facultative wetland (FACW) and obligate (OBL) shrubs and bog‑like plants generally known from boreal areas of North America. This feature was determined to be a jurisdictional wetland according to the field study using the USACE Manual and criteria. It was also a rare, glacial relic found very, very infre‑ quently at that given latitude. The delineator revealed that he or she knew of the presence of the feature in the area but not its location and was not sure until it was found that it was truly “out there” or just a hopeful story based on its extreme rarity in the region. Imagine the chagrin of the “messenger” should this feature have been revealed during the inspection, rather than a priori following due diligence and procedures espoused in previous chapters. The regulators are used to doing a great deal of the permitting work in the office, from their sources, and from the wetland and/or environmental reports supplied by the landowner or their designee. They also enjoy the field inspection to get the “lay

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of the land” and to see the resources in person and to evaluate the completeness of the report and the accuracy and adequacy of the flagged and recorded wetland boundaries. Due to the daily schedule of the regulators, the portfolio of inspections, their per‑ mit load, and processing schedule of the permits, a field visit could come at any time after the report is filed and the “clock is running.” On the day of field inspection, arrive early, because the regulators may do the same. They will likely know the area and the wetland resources found there and may check things before you arrive. The visit will also provide some information as to what details of the site are interesting to them. They will also know the subtypes of wetlands that are tricky to identify and tricky as to the laying of their boundaries in the field. They are also capable of evaluating a given site at any time of the year, providing that the site is not covered by snow or by deep floodwaters or obscured in some other way. Once upon a time a delineator went on an inspection of a very large piece of prop‑ erty numbering in the hundreds of acres. Present were the regulators and their expert soil scientist, or so it was said. The expert soil person saw tiny mottles in almost all soil areas that were examined. This was certainly possible in the heavy, clayey min‑ eral soils present and the high quantities of rainfall typically found in the growing season in this particular area or region. But did it mean that the given location was a hydric soil and hydromorphic in development, and could it meet the growing season test? Were these “prior converted croplands” a jurisdictional wetland in “mufti,” as thought the delineator? These expert‑driven observations called the boundaries into question. The regulators and the delineator then agreed upon a different, larger area boundary in the field and it was reflagged and remapped for inspection and permit‑ ting purposes. This brings an important issue to bear. The property owner needs the permit. The regulators need to process the permit applications. The delineator has their report and boundaries in the field and is displaying their “wares” in the field at the inspec‑ tion. The delineator is confident of his/her work and expertise. The regulators are confident of their work and expertise. If the regulators and delineator can agree on a boundary, the work of the inspection is done and the permit will likely go forward to the next step. If at the field inspection step, the regulators and delineator are not in agreement and cannot come to an agreement then and there, a delay is created. What would the gentle reader do under the circumstances? Engage in the battle of the experts or seek a common boundary acceptable to both parties at the inspection? Also, such a delay will likely will go against the landowner’s schedule rather than that of the regulator’s. Another time a delineator went on an inspection. About five people came from the regulatory side of the house. They introduced themselves as “Sam,” “Julie,” “Dan,” and so forth. There followed a nice inspection of a pretty active farm, farmhouse, farm pond, and copse of woods. As the get‑together unfolded, the boundary was agreed upon and examined. Polite discussions focused on some of the plant iden‑ tifications, which were nicely authenticated by Dan, professor of botany at a local university and a likely co-author of the Wetlands Manual (USACE 1987), and by

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Sam, the chief of the regulatory administrative unit of the regulatory agency. The delineators always enjoy folks to see their work, and it is always nice to have the work checked by talented people. When attending a field inspection and a bunch of people show up, it is appropriate to request business cards so that one knows the identity of those who checked the delineator’s work. Another time a delineator went to a controversial site. The regulators and the land‑ owners where trying to iterate to a solution as to whether there had been a “discharge into waters.” The delineator knew this was a tricky issue because the attendees were trying to agree to a, “after the fact” style of permit. A trio of Ford police interceptors disgorged six or more regulators for the get‑together. The delineator presented what facts he/she could, given the mound of “discharge” covering the site in multiple foot depths and did so to the willing, eager, and well‑equipped small “high school foot‑ ball team” of regulators in attendance. “Gosh,” the delineator went on to account that one could have “cut the air with a knife.” This was a valuable lesson in the maxim of bringing like quantities to the parlay; that is, if there are six or more of them, the delineator ought to bring six or more from their “team.” Another time a delineator completed a report on a very large property that had very few if any wetlands. It did have one small patch of wetlands‑looking ground right in the middle of a “footprint” of a proposed building. The wet‑looking area was small and very alone in the grand scheme of the development and very marginal whether it was or was not a jurisdictional wetland. It was the dead of winter, and the delineator had laid a boundary based on soil type and the presence of plant residue and flagged and readied the site for inspec‑ tion. If memory serves well, the dominant plant in these “prior converted croplands” that were actively cultivated at that time was a grass species that was facultative wetland upland (FACU), and the patch was approximately one half of one acre in area or size. On inspection day, in a light snow but with bare ground, the delineator arrived a little early in time to find the lone regulator actively revising the wetland boundary with flagging tape in hand. The regulator was done early with regard to neighbor‑ ing work and was making good use of time so that he/she could return to the home office some distance away before the storm may have broke into true fury. This revised boundary was based on his/her “eye” without regard to the FACU status of the residue of the dominant plant. Nor did he/she wish to “hear about it.” The result‑ ing altered boundary was agreed upon and the permit was issued, with no harm to the regulator and no harm to the landowner. This brings forth to mind the maxim that it may be fine and may be good sport to “shoot the messenger.” It is also part of the maxim that the regulator is “fixed in the picture,” the landowner and/or agent of development is fixed in the picture, but the messenger is disposable or not fixed in the picture. He/she can be “shot” or “hung,” or, like the Pony Express, be replaced by messages conducted by the train, by airmail on planes, or most recently by electronic means of messaging or message delivery. Hence, be aware of the whole picture. Know the surrounding area and issues. Be aware of both parties who are fixed in the picture.

10

Conclusions

WHERE WE ARE Over 20 years have passed since the advent of “no net loss of wetlands.” The nation has made great progress in understanding the resource, bringing issues to the fore‑ front, and preserving, maintaining, and enhancing wetlands. The landscape or “lay of the land” for the issues is very different today and will be in the future. As Voltaire may have first said, the only thing constant is change. The advent of the Supreme Court decisions and their interpretation has been mul‑ tifold. The decisions have called on all parties to reexamine the meaning of wetlands and the jurisdictional issues. They have called into question the practices of delineating wetlands and definitions of jurisdiction and their application in a variety of places. Implementation is an altogether different issue. Establishment of jurisdiction is complex and variable across the nation. Delineation of a wetland requires the setting of a boundary or line that represents an interpretation of the definition of wetland resources. And the definition of the boundary is changing or will be changing.

WHERE WE ARE GOING On the horizon are legislative actions. They run the gamut from a “thirst” over the years to make wholesale updates or improvements to laws and/or modifications of the language by amendment, most notably to the Federal Water Pollution Control Act or, as it is commonly known, the Clean Water Act of 1972 (CWA) as amended. Of particular interest is the advent of the Clean Water Restoration Act (CWRA), with its various ideas and forms. Advocates seek to further modify the CWA and to clarify jurisdiction of the waters in the United States. The antecedents are many and include the Federal Wetlands Jurisdiction Act of 2005 (H.R. 2658) and the effort to “… Amend the Federal Water Pollution Control Act to Clarify the Jurisdiction of the United States over Water of the United States” of 2007 (H.R. 2421) and the Senate CWRA of the 111th Congress (S. 787). These legislative actions and the Supreme Court Decision demonstrate that the ideas have “legs” or perseverance. It has created a myriad of commentary from all sides.

HYDROLOGY, CONNECTIVITY, AND JURISDICTION A great deal of dialogue has taken place concerning the 2006 decision Rapanos v. United States, henceforth referred to here as the Supreme Court Decision or Decision (547 U.S. 715). The reader is urged to view references, Web sites, and blogs included to inform themselves of the details. The following is a lay or non‑lawyerly 169

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description of the decision, how it has been interpreted, and how it influences or may influence wetland identification and delineation. The Supreme Court Decision was a “split” example: four justices were in the affirmative, four justices were in the negative, and Justice Kennedy wrote an inde‑ pendent opinion that advanced the affirmative Decision. Hence five justices agreed to void rulings against the plaintiffs. Circuit courts have been using the Decision in several manners. Some have applied the first example as a test. Some have applied a combination of the first example and Kennedy as tests. Some have applied as a test either the first example or Kennedy. Federal agencies have often applied the “or” examples in their findings. Naturally, this all can change due to subsequent interpretation by the courts, by rule‑making, and by legislation. Hence, it is necessary in permitting activities to be aware of national and regional interpretations or applications of jurisdiction by courts by federal government agencies and by any prevailing local or regional practices. Yet the water resource definitions and the boundary issues thereof are also a chal‑ lenge for the delineator to demonstrate on the lay of the land.

DEFINITIONS Over the years, people have tried to create definitions for something “near and dear” to them—wetlands. Yet they are a mix of things, because aquatic and terrestrial environments have very different characteristics. In general, where water or wet meets terra firma or land, there is an opportunity for a wetland. Wetlands are transitory or ephemeral in some cases. They are stable in extent in other cases. In either case, a landform or entity can be recognized. This is done according to definitions. In this changing landscape of ideas and implementation activities, therein lies the opportunity to apply enhanced technologies and methods for characterization. We have a number of tools to delineate jurisdictional wetlands or to define or map general wetlands or potential jurisdictional wetlands. From these opportunities and with tools, we can determine what the area is indeed. The book provides methods to apply the reigning definitions and supply informa‑ tion. One can then make a finding and document the basis of the finding for report‑ ing purposes.

ADVANCED AND ENHANCED METHODS Over 17 years have passed since the first edition of this book. Though still useful and still in print, we all have learned more that can be shared. The dialogue has changed, and so have the issues as they have matured. Because many factors have remained the same over the last 20 years, these differ‑ ent conditions further complicate the view. Now with operational guides and methods, the underlying assumptions on condi‑ tions have changed, yielding new challenges. The challenges include the change in the rate of land development for commercial and homeowner properties and the dif‑ ferent possible interpretations of waters of the United States.

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New technologies, enhanced methods, and more widely available data and infor‑ mation all help to better characterize wetland conditions on a given property. We hope to offer a number of methods that can help clarify water boundaries or pro‑ vide “lines” to help understand the issue regionally and make a clarification locally. These methods have the hope of bringing clarity to issues for all parties. High‑quality data and their interpretations can bring facts to the dialogue. When matched up with the understood definitions in the permitting process, a lot of good can come to decision‑making activities.

WHERE ARE WE GOING? Where do we establish the jurisdiction? Where do we establish the line? A variety of technologies may be characterized as geospatial or mapping approaches. These include a suite of older, tested approaches and newer examples. All can be employed with the prevailing criteria to establish the line or boundary and with that the jurisdiction. They also can be applied as the need for information goes beyond that supplied by field‑expedient methods and consensus‑based deci‑ sions for permitting. The United States is obviously a diverse place, and what may work in southern Florida may be very different in the Aleutian Islands of Alaska. One size will not fit all. Yet how does the nation applied accepted criteria uniformly and in a manner that can be understood by all or most all? What definitions of the boundaries of water conveyances are to be used and how are they recognized in the field, from maps and images, and in permitting activities? The definitions and issues are being clarified, but change is the harbinger. There exist a lot of good questions, typically advanced by very thoughtful people with more than passing interests. We learned long ago that the “easiest thing in the world is to ask a hard question” which is fine, particularly by thoughtful minds. Yet it is likewise important to offer up solutions—partial, whole, or otherwise. This book encompasses our answers to many of those thoughtful questions and hope that the answers will help bring clarity to the dialogue.

Appendix: Plant‑Related References The following references have been found to be useful for identification of upland and wetland plants. They range in content from books covering the regional types and distribution of plants to books that address national or North American distri‑ butions. They also range in the level of detail they supply in describing the plants. These books will be potentially helpful in delineation when used along with local books on plants. Agricultural Research Service. 1971. Common weeds of the United States. Washington, D.C. and New York, N.Y.: U.S. Department of Agriculture and Dover Publications. Billington, C. 1968. Shrubs of Michigan. Bloomfield Hills, Mich.: Cranbrook Institute for Science. Braun, E. L. 1964. Deciduous forests of eastern North America. New York, N.Y.: Hafner. Braun, E. L. 1989. The woody plants of Ohio. Columbus: Ohio State University Press. Britton, N., and A. Brown. 1970. An illustrated flora of the northern United States and Canada. Vols. 1–3. New York, N.Y.: Dover Publications. Brown, L. 1977. Weeds in winter. Boston: Houghton Mifflin. Brown, L. 1979. Grasses. Boston: Houghton Mifflin. Cobb, B. 1963. Ferns. Boston: Houghton Mifflin. Correll, D. 1975. Aquatic and wetland plants of the southwestern United States. Vols. 1 and 2. Stanford, Calif.: Stanford University Press. Courtenay, B., and J. Zimmerman. 1972. Wildflowers and weeds. New York, N.Y.: Van Nostrand Reinhold. Crow, G., and C. Hellquist. 2005. Aquatic and wetland plants of Northeastern North America. Vol.1. Madison: University of Wisconsin Press. Dana, W. 1963. How to know the wild flowers. New York, N.Y.: Dover Publications. Fassett, N. 1951. Grasses of Wisconsin. Madison: University of Wisconsin Press. Fassett, N. 1957. A manual of aquatic plants. Madison: University of Wisconsin Press. Fassett, N. 1978. Spring flora of Wisconsin. Madison: University of Wisconsin Press. Fisher, T. 1988. The Dicotyledoneae of Ohio, part three, Asteraceae. Columbus: Ohio State University Press. Forey, P. 1990. Wildflowers. New York, N.Y.: Gallery Books. Godfrey, R., and J. Wooten. 2005a. Pteridophytes, gymnosperms, and angiosperms. Vol. 1 of Aquatic and wetland plants of Southeastern United States. Madison: University of Wisconsin Press. Godfrey, R., and J. Wooten. 2005b. Angiosperms, monocotyledons. Vol. 2 of Aquatic and wet‑ land plants of Southeastern United States. Madison: University of Wisconsin Press. Harlow, W. 1946. Fruit key and twig key. New York, N.Y.: Dover Publications. Harlow, W. 1957. Trees of the eastern and central United States and Canada. New York, N.Y.: Dover Publications. Harrington, H. 1957. How to identify grasses: And grasslike plants. Athens: SwallowPress/ Ohio University Press. Hipp, A. 2008. Field guide to Wisconsin sedges: An introduction to the Genus Carex (Cyperaceae). Madison: University of Wisconsin Press.

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Hitchcock, A. 1971. Manual of the grasses of the United States. Vols. 1 and 2. New York, N.Y.: Dover Publications. Hotchkiss, N. 1972. Common marsh underwater and floating‑leaved plants of the United States and Canada. New York, N.Y.: Dover Publications. Kartesz, J. 1994a. Checklist. Vol. 1 of A synchronized checklist of the vascular flora of the United States, Canada, and Greenland. Portland, Ore.: Timber Press. Kartesz, J. 1994b. Thesaurus. Vol. 2 of A synchronized checklist of the vascular flora of the United States, Canada, and Greenland. Portland, Ore.: Timber Press. Knobel, E. 1977. Field guide to the grasses, sedges and rushes of the United States. New York, N.Y.: Dover Publications. Knobel, E. 1988. Identify trees and shrubs by their leaves, a guide to trees and shrubs native to the Northeast. New York, N.Y.: Dover Publications. Lellinger, D. 1985. A field manual of ferns and fern‑allies of the United States and Canada. Washington, D.C.: Smithsonian Institution. Little, E. 1979. Forest trees of the U.S. and Canada, and how to identify them. New York, N.Y.: Dover Publications. Little, E. 1980. The Audubon Society field guide to North American trees, Eastern region. New York, N.Y.: A. Knopf. Martin, E. 1984. A beginner’s guide to wildflowers of the C and O towpath. Washington, D.C.: Smithsonian Institution. Miller, H., and S. Lamb. 1985. Oaks of North America. Happy Camp, Calif.: Naturegraph Publishers. Mohlenbrock, R. 1987. Wildflowers, a quick identification guide to the wildflowers of North America. New York, N.Y.: Macmillan Publishers. Mohlenbrock, R., and J. Thieret. 1987. Trees, a quick reference guide to trees of North America. New York, N.Y.: Macmillan Publishers. Newcomb, L. 1977. Newcomb’s wildflower guide. Boston: Little, Brown and Company. Niering, W., and N. Olmstead. 1979. The Audubon Society field guide to North American wild‑ flowers, eastern region. New York, N.Y.: A. Knopf. Peterson, R., and M. McKenny. 1968. A field guide to wildflowers of northeastern and north‑central North America. Boston: Houghton Mifflin. Petrides, G. 1988. A field guide to eastern trees, eastern U.S. and North America. Boston: Houghton Mifflin. Preston, R. 1989. North American trees. Ames: Iowa State University Press. Sargent, C. 1969. Manual of the trees of North America. Vols. 1 and 2. New York, N.Y.: Dover Publications. Smith, H. 1966. Michigan wildflowers. Bloomfield Hills, Mich.: Cranbrook Institute for Science. Spencer, E. 1957. All about weeds. New York, N.Y.: Dover Publications. Symonds, G. 1958. The tree identification book. New York, N.Y.: William Morrow. Symonds, G. 1973. The shrub identification book. New York, N.Y.: William Morrow. Trelease, W. 1967. Winter botany, an identification guide to native trees and shrubs. New York, N.Y.: Dover Publications. U.S. Army Corps of Engineers. 1977. Wetland plants of the eastern United States. NADP 200‑1‑1. New York, N.Y.: North Atlantic Division. U.S. Army Corps of Engineers. 1979. A supplement to wetland plants of the eastern United States. NADP 200‑1‑1 supplement 1. New York, N.Y.: North Atlantic Division. U.S. Department of Agriculture. 1973. Silvicultural systems for the major forest types of the U.S. Agriculture Handbook No. 445. Washington, D.C.: U.S. Forest Service. Uva, R., J. Neal, and J. Ditomaso. 1997. Weeds of the northeast. Ithaca, N.Y.: Cornell University Press. Voss, E. 1972. Michigan flora, part I: Gymnosperms and monocots. Bloomfield Hills, Mich.: Cranbrook Institute of Science. Voss, E. 1996. Michigan flora, part III: Dicots concluded. Bloomfield Hills and Ann Arbor, Mich.: Cranbrook Institute of Science and University of Michigan Herbarium.

References Adamus, P., L. Stockwell, E. Clairain, M. Morrow, L. Rozas, and R. Smith. 1991. Wetland eval‑ uation technique (WET). Technical Report WRP‑DE‑2. Vicksburg, Miss.: Waterways Experiment System, U.S. Army Corps of Engineers. Advanced Resources International. 2001. Using satellite radar imagery to detect leading aban‑ doned oil wells on the U.S. Outer Continental Shelf. Phase I technology demonstration, Final Report. Herndon, Va.: U.S. Minerals Management Service. Agricultural Research Service. 1971. Common weeds of the United States. Washington, D.C. and New York, N.Y.: U.S. Department of Agriculture and Dover Publications. Ainslie, W, R. Smith, B. Pruitt, T. Roberts, E. Sparks, L. West, G. Godshalk, and M. Miller. 1999. A regional guidebook for assessing the functions of low gradient, riverine wet‑ lands in western Kentucky. Technical Report WRP‑DE‑17. Vicksburg, Miss.: U.S. Army Engineer Waterways Experiment Station. American Society of Mechanical Engineers. 2008. ASME water management technology vision and roadmap: Executive summary. Washington, D.C. ASME. American Society of Photogrammetry and Remote Sensing. 1990. ASPRS accuracy stan‑ dards for large‑scale maps. Photogrammetric Engineering and Remote Sensing 56:1068–1070. Anderson, J., E. Hardy, J. Roach, and R. Witmer. 1976. A land use classification system for use with remote‑sensor data. U.S. Geological Survey Professional Paper 964. Washington, D.C.: U.S. Department of Interior. Anderson, J., and J. Perry. 1996. Characterization of wetland plant stress using leaf reflectance spectra: Implications for wetlands remote sensing. Wetlands 16:477–487. Andreas, B., and R. Lichvar. 1995. Floristic index for establishing assessment standards: A case study for northern Ohio. Technical Report WRP‑DE‑8. Vicksburg, Miss.: U.S. Army Engineer Waterways Experiment Station. Anger, R. 2003. A soil survey enhancement of Landsat Thematic Mapper delineation of wet‑ lands: A case study of Barry county. Master’s thesis, Western Michigan University, Kalamazoo, Mich. Argialas, D., J. Lyon, and O. Mintzer. 1988. Quantitative description and classification of drainage patterns. Photogrammetric Engineering and Remote Sensing 54:505–509. Artigas, F., and J. Yang. 2005. Hyperspectral remote sensing of marsh species and plant vigor gradient in the New Jersey Meadowlands. International Journal of Remote Sensing 26:5209–5220. Barrette, J., P. August, and F. Golet. 2000. Accuracy assessment of wetland boundary delin‑ eation using aerial photography and digital orthophotography. Photogrammetric Engineering and Remote Sensing 66:409–416. Becker, B., D. Lusch, and J. Qi. 2007. A classification‑based assessment of the optimal spec‑ tral and spatial resolutions of coastal wetland imagery. Remote Sensing of Environment 108:111–120. Belluco, E., M. Camuffo, S. Ferrari, L. Modenese, S. Silvestri, A. Marani, and M. Marani. 2006. Mapping salt‑marsh vegetation by multispectral and hyperspectral remote sens‑ ing. Remote Sensing of Environment 105:54–67. Berkowitz, J. 2009. Using IRIS tubes to monitor reduced conditions in soils—Project design. ERDC TN‑WRAP‑09‑1. Vicksburg, Miss.: U.S. Army Engineer Research and Development Center. Billington, C. 1968. Shrubs of Michigan. Bloomfield Hills, Mich.: Cranbrook Institute for Science. 175

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Brinson, M. 1993. A hydrogeomorphic classification for wetlands. Technical Report WRP‑DE‑4. Vicksburg, Miss.: U.S. Army Engineer Waterways Experimental Station. Brinson, M., F. Hauer, L. Lee, W. Nutter, R. Rheinhardt, R. Smith, and D. Whigham. 1995. A guidebook for application of hydrogeomorphic assessments to riverine wetlands. Technical Report WRP‑DE‑11. Vicksburg, Miss.: U.S. Army Engineer Waterways Experiment Station. Britton, N., and A. Brown. 1970. An illustrated flora of the northern United States and Canada. Vols. 1–3. New York, N.Y.: Dover Publications. Bukata, R., J. Bruton, J. Jerome, and W. Haras. 1987. A mathematical description of the effects of prolonged water level fluctuations on the areal extent of marshland. Report RRB‑87‑02. Burlington, Canada: Canada Centre for Inland Waters. Bukata, R., J. Jerome, K. Kondratyev, and D. Pozdnyakov. 1995. Optical properties and remote sensing of inland and coastal waters. Boca Raton, Fla.: CRC Press. Butera, K. 1983. Remote sensing of wetlands. IEEE Transactions on Geoscience and Remote Sensing GE‑21:383‑392. Campbell, J. 2002. Introduction to remote sensing. 3rd Edition. New York: Guilford Press. Carter, V. 1990. Importance of hydrologic data for interpreting wetland maps and assessing wetland loss and mitigation. Federal Coastal Wetland Mapping Programs, Biology Report 90 (18). Washington, D.C.: U.S. Fish and Wildlife Service. Clairain, E. 2002. Introduction and overview of the hydrogeomorphic approach. In: Hydrogeomorphic approach to assessing wetland functions: Guidelines for develop‑ ing regional guidebooks. ERDC/EL TR‑02‑3. Vicksburg, Miss.: U.S. Army Engineer Research and Development Center. Congalton, R., and K. Green. 1998. Accuracy assessment of remotely sensed data: Principles and Practices. Boca Raton, Fla.: CRC/Lewis Publishers. Congalton R., and K. Green. 2009. Assessing the accuracy of remotely sensed data: Principles and Practices, 2nd Edition. Boca Raton, Fla.: CRC Press. Cole, C., R. Brooks, and D. Wardrop. 1997. Wetland hydrology as a function of hydrogeomor‑ phic (HGM) subclass. Wetlands 17:456–467. Costa, M, O. Niemann, E. Novo, and F. Ahern. 2002. Biophysical properties and mapping of aquatic vegetation during the hydrological cycle of the Amazon floodplain using JERS‑1 and Radarsat. International Journal of Remote Sensing 23:1401–1426. Courtenay, B., and J. Zimmerman. 1972. Wildflowers and weeds. New York, N.Y.: Van Nostrand Reinhold. Cowardin, L., V. Carter, F. Golet, and E. LaRoe. 1979. Classification of wetlands and deepwa‑ ter habitats of the United States. Report No. FWS/OBS‑79/31. Washington, D.C.: U.S. Department of Interior, U.S. Fish and Wildlife Service. Dahl, T. 2006. Status and trends of wetlands in the conterminous United States 1998 to 2004. Washington, D.C.: U.S. Fish and Wildlife Service. Dana, W. 1963. How to know the wild flowers. New York, N.Y.: Dover Publications. De Roeck, E., N. Verhoest, M. Miya, H. Lievens, O. Batelaan, A. Thomas, and L. Brendonck. 2008. Remote sensing and wetland ecology: A South African case study. Sensors 8:3542–3556. Dibble, E., J. Hoover, and M. Landin. 1995. Comparison of abundance and diversity of young fishes and macroinvertebrates between two Lake Erie wetlands. Technical Report WRP‑RE‑7. Vicksburg, Miss.: U.S. Army Engineer Waterways Experiment Station. Dobson, J., and E. Bright. 1993. Large‑area change analysis: The Coastwatch Change Analysis Project (CCAP). Paper read at the 12th Pecora Symposium, Sioux Falls, S.D. Dunne, K., A. Rodrigo, and E. Samanns. 1998. Engineering specification guidelines for wet‑ land plant establishment and subgrade preparation. Technical Report WRP‑RE‑19. Vicksburg, Miss.: U.S. Army Engineer Waterways Experiment Station.

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