Hydraulic Tests of Miocene Volcanic Rocks at Yucca Mountain and Pahute Mesa and Implications for Groundwater Flow in the Southwest Nevada Volcanic Field, Nevada and California (GSA Special Paper 381)

Special Paper 381

. . THE GEOLOGICAL SOCIETY • oF AMERICA

Hydraulic Tests of Miocene Volcanic Rocks at Yucca Mountain and Pahute Mesa and Implications for Groundwater Flow in the Southwest Nevada Volcanic Field, Nevada and California

by Arthur l. Geldon

Hydraulic tests of Miocene volcanic rocks at Yucca Mountain and Pahute Mesa and implications for groundwater flow in the Southwest Nevada Volcanic Field, Nevada and California

by Arthur L. Geldon Fractured Planet Hydrogeologic Consulting 10104 W. Lake Drive Littleton, Colorado 80127 USA

Special Paper 381 3300 Penrose Place, P.O. Box 9140

Boulder, Colorado 80301-9140 USA

2004

Copyright © 2004, The Geological Society of America, Inc. (GSA). All rights reserved. GSA grants permission to individual scientists to make unlimited photocopies of one or more items from this volume for noncommercial purposes advancing science or education, including classroom use. For permission to make photocopies of any item in this volume for other noncommercial, nonprofit purposes, contact the Geological Society of America. Written permission is required from GSA for all other forms of capture or reproduction of any item in the volume including, but not limited to, all types of electronic or digital scanning or other digital or manual transformation of articles or any portion thereof, such as abstracts, into computer-readable and/or transmittable form for personal or corporate use, either noncommercial or commercial, for-profit or otherwise. Send permission requests to GSA Copyright Permissions, 3300 Penrose Place, P.O. Box 9140, Boulder, Colorado 80301-9140, USA. Copyright is not claimed on any material prepared wholly by government employees within the scope of their employment. Published by The Geological Society of America, Inc. 3300 Penrose Place, P.O. Box 9140, Boulder, Colorado 80301-9140, USA www.geosociety.org Printed in U.S.A. GSA Books Science Editor: Abhijit Basu Library of Congress Cataloging-in-Publication Data Geldon, Arthur L. Hydraulic tests of Miocene volcanic rocks at Yucca Mountain and Pahute Mesa and implications for groundwater flow in the Southwest Nevada Volcanic field, Nevada and California / by Arthur L. Geldon. p. cm. — (Special paper ; 381) Includes bibliographic references. ISBN 0-8137-2381-7 (pbk.) 1. Groundwater flow--Nevada--Pahute Mesa. 2. Groundwater flow--Nevada--Yucca Mountain. 3. Geology, Stratigraphic--Miocene. 4. Rocks--Nevada--Pahute Mesa--Permeability. 5. Rocks--Nevada-Yucca Mountain--Permeability. 6. Aquifers--Testing. 7. Borings--Nevada--Pahute Mesa. 8. Borings-Nevada--Yucca Mountain. I. Title. II. Special papers (Geological Society of America) ; 381. GB1025.N4G45 2004 551.49’09793—dc22 2004054589 Cover: Northern end of Yucca Mountain (right) and Tram Ridge (left), looking up Solitario Canyon from Crater Flat.

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Contents Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Location of Study Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Regional Geology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Regional Groundwater Hydrology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Hydrostratigraphic Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Groundwater in the Younger Tertiary Tuff and Lava Flows Hydrostratigraphic Unit . . . . . . . . . . . . . 13 Hydraulic Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Well Completion and Instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Flow Distribution in Boreholes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Earth Tides and Barometric Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Analytical Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Constant-Rate Pumping, Injection, and Airlift Tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Slug-Injection and Swabbing Recovery Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Analytical Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Effects of Test Scale on Determination of Hydraulic Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Hydraulic Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 The C-holes Complex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Pumping Test in UE-25 c#3, May 22 to June 1, 1995. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Miscellaneous Hydraulic Tests at the C-holes Complex, 1984–1998. . . . . . . . . . . . . . . . . . . . . . . 49 Pumping Test in UE-25 c#3, May 8, 1996, to November 12, 1997 . . . . . . . . . . . . . . . . . . . . . . . . 52 Drill Hole Wash . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Frenchman Flat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 Well Cluster ER-20-6, Western Pahute Mesa. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Knickerbocker Site, Western Pahute Mesa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Distribution of Hydraulic Conductivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 Relation of Lithology to Hydraulic Conductivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Hydraulic Conductivity Distribution at Yucca Mountain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Hydraulic Conductivity Distribution at Pahute Mesa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Summary and Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Appendix A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Appendix B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 References Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

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Geological Society of America Special Paper 381 2004

Hydraulic tests of Miocene volcanic rocks at Yucca Mountain and Pahute Mesa and implications for groundwater flow in the Southwest Nevada Volcanic Field, Nevada and California Arthur L. Geldon* Fractured Planet Hydrogeologic Consulting, 10104 W. Lake Drive, Littleton, Colorado, 80127, USA INTRODUCTION Yucca Mountain is a windswept, barren, volcanic ridge ~150 km northwest of Las Vegas, Nevada (Fig. 1). From its summit, one looks out on vast panoramas of emptiness—Crater Flat to the west, Jackass Flats to the east, and the Amargosa Desert and mountains flanking Death Valley to the south. In an endlessly repeating series of ridges, mesas, and narrow mountain ranges that protrude above broad, sediment-filled basins in the Great Basin desert, Yucca Mountain is inconspicuous. It is unremarkable, except that the United States government has chosen Yucca Mountain to be the site of the first permanent repository in the nation for storing nearly 60 years of accumulated high-level nuclear waste. Consequently, the U.S. Department of Energy (DOE), the U.S. Geological Survey (USGS), the Nye County Nuclear Waste Repository Project Office, the national laboratories (Los Alamos, Sandia, Lawrence Berkeley), and other interested parties have conducted extensive geological, hydrological, geophysical, and geochemical studies to justify selecting Yucca Mountain as the final resting place for the nation’s nuclear junk. About 25 km north of Yucca Mountain, in the northwest corner of the Nevada Test Site, is Pahute Mesa, a high volcanic plateau (Fig. 2). Between 1966 and 1991, 85 nuclear devices were exploded beneath this plateau, which makes Pahute Mesa the site of the second largest number of nuclear tests conducted on the Nevada Test Site (Townsend and Grossman, 2001). All of these tests were conducted in vertical emplacement holes, most of which extended near or below the water table. Numerous exploratory and observation wells were drilled to obtain geologic and hydrologic data before and after detonations. During the nuclear testing period, hydraulic testing was done in exploratory observation, and emplacement boreholes as opportunities arose. Since

Figure 1. Yucca Mountain, Nevada, looking south from the crest to Jackass Flats, the Amargosa Desert, and the Funeral Mountains.

Figure 2. Pahute Mesa and Oasis Valley looking north from Tram Ridge.

*[email protected]

Geldon, A.L., 2004, Hydraulic tests of Miocene volcanic rocks at Yucca Mountain and Pahute Mesa and implications for groundwater flow in the Southwest Nevada Volcanic Field, Nevada and California: Geological Society of America Special Paper 381, 93 p. For permission to copy, contact [email protected]. © 2004 Geological Society of America

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A.L. Geldon

1990, the U.S. Department of Energy has conducted the multidisciplinary Underground Testing Areas (UGTA) project to evaluate contaminant transport by groundwater flow on the Nevada Test Site and in hydraulically downgradient areas. A three-dimensional groundwater model was developed to evaluate the Death Valley regional groundwater flow system (IT Corporation, 1997a), and similar models are being developed for specific Nevada Test Site nuclear-test areas (e.g., IT Corporation, 1998c). Yucca Mountain and Pahute Mesa form much of the eastern part of the Southwest Nevada Volcanic Field, a voluminous outpouring of predominantly silicic to intermediate Miocene volcanic rocks (Warren et al., 1998). The several hundred hydraulic tests conducted at Yucca Mountain and Pahute Mesa from 1958 to 1999 to support the nation’s nuclear agenda provide insights into the hydrogeology of the entire Southwest Nevada Volcanic Field. In this report, groundwater flow in the Southwest Nevada Volcanic Field, a non-stratiform, fracture-dominated aquifer system, is discussed. Approaches to studying hydraulic properties of the volcanic rocks in the Southwest Nevada Volcanic Field, which were proven by trial and error to be effective at Yucca Mountain and Pahute Mesa, are proposed as models for future hydrologic studies in the volcanic field. Factors that affected analysis of hydraulic tests, such as test scale, Earth tides, atmospheric pressure, and water temperature, are discussed. Transmissivity, hydraulic conductivity, and storativity of Miocene volcanic rocks in the Southwest Nevada Volcanic Field are quantified, and spatial and statistical distributions of these hydraulic properties are presented. Material presented in this study is the culmination of research started while the author was employed as a hydrologist by the USGS on the Yucca Mountain Project and the Death Valley Flow System regional modeling study from 1987 to 2001. This study builds upon, and somewhat supersedes, ideas expressed by the author in six USGS and DOE reports and two abstracts that are cited throughout. The author acknowledges funding by the USGS and the support of colleagues that were required to conduct this study. LOCATION OF STUDY AREA Yucca Mountain, Pahute Mesa, and the Southwest Nevada Volcanic Field are in the Death Valley region of the Great Basin. The Death Valley region is located in southeastern California and Nevada between latitudes 35° and 38°15′ N and longitudes 115° and 118° W (Fig. 3). The area of the Death Valley region varies according to the purpose for which boundaries are delineated. For example, IT Corporation (1997a) incorporated an area of 26,200 km2 in its three-dimensional groundwater flow model of the Death Valley region. Laczniak et al. (1996) conceptualized groundwater flow within an area of ~40,900 km2. Workman et al. (2002) presented a geologic map of the Death Valley region with an area of 57,000 km2, which is slightly larger than the area of a regional groundwater flow model that currently is being developed by the USGS (D’Agnese and Faunt, 1999).

The terrain in the Death Valley region typically consists of northerly and northwesterly trending mountain ranges surrounded by broad sediment-filled basins. The Spring Mountains, the highest topographic feature in the area, rise to an altitude of more than 3600 m above mean sea level (AMSL). Summit altitudes on Pahute Mesa increase eastward from 1800 m to 2250 m AMSL (Minor et al., 1993). Yucca Mountain, which consists of a series of northerly trending ridges, crests at an altitude of ~1760 m AMSL (Day et al., 1998). Intermontane basins bordering Pahute Mesa and Yucca Mountain include Oasis Valley and Crater Flat on the west, Sarcobatus Flat and the Amargosa Desert on the south, Jackass Flats, Frenchman Flat, and Yucca Flat on the east, and Emigrant Valley, Kawich Valley, and Gold Flat on the north. Death Valley, the topographically lowest feature in the region, descends to an altitude of 86 m below sea level. Death Valley National Park and the Ash Meadows National Wildlife Refuge are hydraulically downgradient from Yucca Mountain. Pahrump, Beatty, and Goldfield, Nevada, are the largest of several small towns in the area. REGIONAL GEOLOGY Geologic units present in the vicinity of Yucca Mountain and Pahute Mesa range from Early Proterozoic to Quaternary in age (Table 1). Figure 4 shows their general distribution. Early Proterozoic (1.7–1.4 b.y. old) gneiss, schist, marble, metaconglomerate, metadiorite, and granite crop out mostly in or near Death Valley (Hunt and Mabey, 1966). Clastic and carbonate sedimentary rocks and diabase of the Late to Middle Proterozoic Pahrump Group overlie the eroded surface of the Early Proterozoic rocks from Death Valley to Pahrump Valley (Hunt and Mabey, 1966). Deposition of the Noonday Dolomite during the Late Proterozoic period marked the beginning of alternately marine and terrestrial sedimentation, which continued without lengthy interruption into the Jurassic period (Laczniak et al., 1996). Late Proterozoic to early Middle Cambrian rocks consist mostly of quartzite, sandstone, and argillite, but carbonate rocks intertongue. Late Middle Cambrian to Middle Devonian rocks consist mostly of limestone and dolomite, but clastic intervals are present. During the Mississippian period, carbonate rocks accumulated in stable shelf areas, and clastic rocks accumulated in foreland basins associated with the Antler Orogeny (Cole and Cashman, 1999). Late Pennsylvanian to Late Permian formations are mostly marine, whereas Triassic and Jurassic formations are mostly terrestrial. Between the Late Proterozoic and Jurassic periods, more than 11,000 m of sedimentary rocks accumulated in the Death Valley region (Winograd and Thordarson, 1975). During the Middle Jurassic to Late Cretaceous Sevier Orogeny, major thrust faults, wrench faults, and folds developed that severely disrupted the stratigraphic continuity of previously deposited sedimentary rocks (Faunt, 1997). Intrusion of granitic magmas, mostly as scattered small stocks, accompanied this tectonic activity and continued after it into

Implications for groundwater flow in the Southwest Nevada Volcanic Field

Stone Cabin Valley

Railroad Valley Reveille Valley

Alkali Spring Valley

Cactus Flat

Stonewall Mountain

Stonewall Flat Goldfield Hills

Quinn Canyon-Death Valley Region Boundary Range

Gold Flat

Kawich Range

Sand Spring Valley

Kawich Valley Belted Range

Emigrant Valley Pahranagat Range Pahute Mesa

Sarcobatus Flat

Timber Yucca Mt Shoshone

Bullfrog Hills Mt Oasis Valley Yucca Mt Beatty Grapevine Mts Crater Jackass Flat Flats

- Nevada Test Site

Frenchman Flat

Amargosa Valley

Indian Springs Valley

Death Valley Funeral Mts

Desert Range

Sheep Range

Amargosa Desert

Ash Meadows

Spring Mts

Alkali Flat

Pahrump Valley

Panamint Range Black Mts

BOUNDARY OF SOUTHWEST NEVADA VOLCANIC FIELD

Figure 3. Geographic features in the Death Valley region, Nevada and California.

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A.L. Geldon TABLE 1. STRATIGRAPHIC COLUMN FOR THE DEATH VALLEY REGION

Geologic age (system)

Geologic units

Quaternary to Pliocene

Late-Middle Proterozoic

Stream, lake, playa, marsh, eolian, fan, evaporite, and spring-carbonate sediments with basalt flows and cinder cones Ash-flow, ash-fall, and reworked tuff; rhyolite to andesite lava flows; and sedimentary rocks Zeolitized and argillized tuff, tuff breccia, sedimentary rocks, and rhyolite to andesite lava flows Granodiorite and quartz monzonite stocks and plutons Aztec Sandstone, Chinle and Moenkopi Formations, Kaibab Limestone, Toroweap Formation, White Rim Sandstone, and Supai Group (mostly as inliers in the Spring Mountains) Bird Spring Formation, equivalent to Tippipah Limestone in Yucca Flat and Ely Limestone in northeast Nye County Scotty Wash Quartzite, Chainman Shale, and Eleana Formation, equivalent in eastern areas to Monte Cristo Group Joana Limestone and Pilot Shale Guilmette Formation Simonson Dolomite Sevy Dolomite (Lone Mountain Dolomite at Bare Mountain) Laketown Dolomite (Roberts Mountain Formation at Bare Mountain) Ely Springs Dolomite Eureka Quartzite Pogonip Group Nopah Formation Bonanza King Formation Carrara Formation Zabriskie Quartzite Wood Canyon Formation Stirling Quartzite Johnnie Formation Noonday Dolomite Pahrump Group

Early Proterozoic

Metamorphic and igneous rocks

Miocene Miocene to Oligocene Eocene to Jurassic Jurassic to Permian

Permian to Pennsylvanian Mississippian

Devonian

Silurian Ordovician

Cambrian

Late Proterozoic

Thickness (m) 0–1220+ 0–3010 175–2500 Unknown 0–2400

1070–2500 300–2040 50–280 350–990 120–365 275–500 250–285 50–200 6–150 320–1050 345–766 580–1700 350–500 30–350 600–1150 700–2100 600–2000 457 1250–1570 Unknown

Note: Compiled from Workman et al., 2002; Warren et al., 1998; Laczniak et al., 1996; Bartley and Gleason, 1990; Hoover and Magner, 1990; Taylor, 1990; Kleinhampl and Ziony, 1985; Ekren et al., 1973; Hunt and Mabey, 1966.

the Tertiary period. During the early Tertiary period, the Death Valley region began to be pulled apart along northerly trending, high-angle, normal faults and northwesterly trending strikeslip faults associated with the Walker Lane Belt (Scott, 1990; Blakely et al., 1999; Fridrich, 1999). Episodic eruptions of tuffaceous rocks and rhyolitic to basaltic lava flows began during the Oligocene epoch. In Oligocene and early Miocene time, several extensive ash-flow tuff sheets were emplaced from northern and eastern source areas (Kleinhampl and Ziony, 1985; Jayko, 1990; Minor et al., 1993). Volcanism in middle to late Miocene time (~16–7 million years ago) formed the Southwest Nevada Volcanic Field. Generalized stratigraphic nomenclature for the Southwest Nevada Volcanic Field in the vicinity of Yucca Mountain and Pahute Mesa is listed in Table 2. The Southwest Nevada Volcanic Field comprises 17 extensive ash-flow tuff sheets and associated lava flows that erupted from at least seven large, overlapping caldera complexes (Laczniak et al., 1996; Warren et al., 1998). Pahute Mesa, at the center

of the Silent Canyon and Timber Mountain caldera complexes, is underlain by thick rhyolite, rhyodacite, and trachyte lava flows intercalated with tuff, whereas Yucca Mountain, on the apron of these caldera complexes, is underlain mostly by tuffaceous rocks (Fig. 5). Tertiary volcanic rocks beneath western Pahute Mesa are >4170 m thick (Blankennagel and Weir, 1973). As volcanism waned from Pliocene to Holocene time, coarse-grained detritus shed from uplifted areas filled syntectonic basins, together with lesser amounts of fine-grained lacustrine, playa, and marsh sediments, eolian sand and silt, evaporite deposits, and spring-carbonate deposits. These basin-fill deposits are >1200 m thick locally (Laczniak et al., 1996). REGIONAL GROUNDWATER HYDROLOGY Yucca Mountain and Pahute Mesa are located at the terminus of a large series of interconnected hydrographic basins that comprise the Great Basin regional aquifer system (Prudic et al., 1993; Plume, 1996). As shown in Figure 6, Yucca Mountain is in the

Implications for groundwater flow in the Southwest Nevada Volcanic Field

Figure 4. Generalized surface distribution of geologic units in the Death Valley region (Laczniak et al., 1996).

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A.L. Geldon TABLE 2. STRATIGRAPHIC NOMENCLATURE OF QUATERNARY AND TERTIARY VOLCANIC ROCKS IN THE VICINITY OF YUCCA MOUNTAIN AND PAHUTE MESA

System

Quaternary

Pliocene

Miocene

Age (ma) 0–0.05 0.05–0.1 0.1–0.9 0.9–1.1 1.1–1.6 1.6–3.7 3.7–5.3 5.3–6.7 6.7–7.3 7.3–7.8 7.8–8.3 8.3–9.0 9.0–9.3 9.3–9.35 9.35–9.4 9.4–9.45 9.45–9.5 9.5–10.0 10.0–10.5 10.5–11.3 11.3–11.45 11.45–11.5 11.5–11.6 11.6–11.67 11.67–11.7 11.7–11.75 11.75–11.8 11.8–12.5 12.5–12.6 12.6–12.7 12.7 12.7–12.75 12.75 12.75–12.76 12.76 12.76–12.8 12.8–13.0

Yucca Mountain, Jackass Flats, and Crater Flat Quaternary Alluvium Basalt of Lathrop Wells Cone Quaternary Alluvium Crater Flat cinder cones Quaternary Alluvium Pliocene Alluvium Basalt of southeast Crater Flat Miocene Alluvium

Western Pahute Mesa, Timber Mountain, and Oasis Valley

Eastern Pahute Mesa, Rainier Mesa, Yucca Flat,and Frenchman Flat

Quaternary Alluvium

Quaternary Alluvium

Pliocene Alluvium

Pliocene Alluvium

Miocene Alluvium

Miocene Alluvium Basalt of Frenchman Flat

Volcanics of Stonewall Mountain Basalt of Yucca Flat Rhyolite of Obsidian Butte

Basalt of Jackass Flats Rhyolite of Shoshone Mountain Basalt of Skull Mountain Ammonia Tanks Tuff Rainier Mesa Tuff Rhyolite of Fluorspar Canyon

Rock avalanche breccia Rhyolite of Windy Wash Rhyolite of Comb Peak Tiva Canyon Tuff Yucca Mountain Tuff Rhyolite of Black Glass Canyon Pah Canyon Tuff Topopah Spring Tuff Calico Hills Formation

Alkali Flat–Furnace Creek groundwater basin, which is bordered on the north and west by the Pahute Mesa–Oasis Valley groundwater basin and on the east by the Ash Meadows groundwater basin. In the Alkali Flat–Furnace Creek groundwater basin and adjacent areas, groundwater moves at local, intermediate, and regional scales through multiple aquifers. In deep structural basins, such as the Amargosa Desert, groundwater flows profusely through basin-fill sediments (Dudley and Larson, 1976; Claasen, 1985). At Yucca Mountain (Luckey et al., 1996) and Pahute Mesa (Laczniak et al.,1996), thick rhyolitic to rhyodacitic lava flows, ash-flow tuff sheets, and bedded tuff deposits can be very transmissive. At Yucca Mountain, high-angle, generally westerly dipping faults disrupt the stratigraphic continuity of easterly dipping volcanic formations (Fig. 7) and cause major production zones in different areas to be located randomly

Trail Ridge Tuff Pahute Mesa Tuff Rocket Wash Tuff Comendite of Ribbon Cliff Basalt of Black Mountain region Rhyolite of Boundary Butte Fortymile Wash Volcanics Ammonia Tanks Tuff Basalt of Oasis Valley Rainier Mesa Tuff Rhyolite of Fluorspar Canyon Tuff of Holmes Road Basalt of Tierra Rhyolite of Windy Wash Rhyolite of Benham Tuff of Pinyon Pass Tiva Canyon Tuff Rhyolite of Delirium Canyon Rhyolite of Echo Peak Rhyolite of Silent Canyon Topopah Spring Tuff Calico Hills Formation

Ammonia Tanks Tuff Rainier Mesa Tuff Tuff of Holmes Road Basalt of Tierra

Rhyolite of Scrugham Peak Tiva Canyon Tuff Rhyolite of Delirium Canyon Rhyolite of Echo Peak Topopah Spring Tuff Calico Hills Formation (continued)

among these formations (Fig. 8). Deep interbasin flow occurs primarily through fractured Paleozoic carbonate rocks (Dettinger et al., 1995). Cambrian to Early Proterozoic quartzite, argillite, and metamorphic rocks compartmentalize groundwater flow within overlying aquifers (Winograd and Thordarson, 1975). In the Alkali Flat–Furnace Creek groundwater basin, relatively sparse precipitation recharges aquifers by infiltration on Pahute Mesa, Timber Mountain, and Shoshone Mountain (D’Agnese et al., 1997). Linear zones of elevated temperature, hydraulic gradients, aquifer tests at Yucca Mountain, and hydrochemical data indicate that additional recharge occurs by water rising from Paleozoic carbonate rocks along northerly trending faults, such as the Midway Valley, Paintbrush Canyon, and Bow Ridge Faults (Fridrich et al., 1994; Geldon et al., 2002). Hydraulic tests indicate that subsurface flow into the Alkali Flat–Furnace

Implications for groundwater flow in the Southwest Nevada Volcanic Field

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TABLE 2. STRATIGRAPHIC NOMENCLATURE OF QUATERNARY AND TERTIARY VOLCANIC ROCKS IN THE VICINITY OF YUCCA MOUNTAIN AND PAHUTE MESA (continued) System

Age (ma)

Miocene

13.0–13.08 13.08–13.09 13.09–13.1 13.1–13.11 13.11–13.12 13.12–13.15 13.15–13.2 13.2–13.33 13.33–13.45 13.45–13.72 13.72–13.75 13.75–13.8 13.8–13.9 13.9–13.97 13.97–14.0 14.0–14.05 14.05–14.15 14.15 14.15–14.2 14.2–14.25 14.25–14.26 14.26–14.3 14.3–14.35 14.35–14.4 14.4–14.5 14.5–15.0 15.0–15.1 15.1–15.15 15.15–15.2 15.2–15.4 15.4–15.55 15.55–15.6 15.6–15.7 15.7–16.2 16.2–16.3

Yucca Mountain, Jackass Flats, and Crater Flat

Western Pahute Mesa, Timber Mountain, and Oasis Valley

Eastern Pahute Mesa, Rainier Mesa, Yucca Flat, and Frenchman Flat

Tuff of Pool Rhyolite of Inlet Basalt of Fontina Tuff of Jorum Prow Pass Tuff Andesite of Grimy Gulch Bullfrog Tuff Tram Tuff Dead Horse Flat Formation

Tuff of Pool Rhyolite of Inlet

Wahmonie Formation

Prow Pass Tuff Bullfrog Tuff Tram Tuff

Grouse Canyon Tuff

Tuff of Jorum Prow Pass Tuff Andesite of Grimy Gulch Bullfrog Tuff Tram Tuff Dead Horse Flat Formation Trachyte of Muenster Grouse Canyon Tuff Comendite of Split Ridge

Andesite and dacite lava flows Lithic Ridge Tuff Units A and B of USW G-1 Rhyolite of Picture Rock Andesite of USW G-2

Tunnel Formation

Comendite of Quartet Dome Rhyolite of Handley Rhyolite of Coyote Cuesta Tuff of Sleeping Butte Tuff of Tolicha Peak Rhyolite of Monte Cristo Spring Rhyolite of Quartz Mountain Volcanics of Mt. Helen

Tunnel bed 2 Tuff of Yucca Flat Red Rock Valley Tuff Tuff of Twin Peaks No Data Tuff of Argillite Wash

Comendite of Quartet Dome

Tunnel Formation

Tub Spring Tuff Tunnel bed 2 Tuff of Yucca Flat Tunnel bed 1 Red Rock Valley Tuff Tuff of Twin Peaks Rhyolite of the Hump Tuff of Argillite Wash

Tuff of Whiterock Spring Tuff of Whiterock Spring Note: Compiled from Orkild and Jenkins (1978); Carr and Parrish (1985); Kilroy and Savard (1996); Plume and La Camera (1996); Robledo et al. (1997); Warren et al. (1998); and Fridrich (1999).

Creek groundwater basin is inhibited by the Solitario Canyon and Southern Windy Wash Faults on the west side of Yucca Mountain and by faults following Fortymile Wash on the east side of Yucca Mountain (Geldon, 2000). Groundwater in the basin generally moves southward and discharges as springflow and evapotranspiration at Oasis Valley, Ash Meadows, Alkali Flat, and Death Valley (Fridrich et al., 1994; Tucci and Burkhardt, 1995; D’Agnese et al., 1997). Figure 9 shows a potentiometric surface and general groundwater flow directions in the Yucca Mountain area that are based on data obtained mostly from 1996 to 2002. Static water levels are in Miocene volcanic rocks, except where these formations pinch out in southeastern Fortymile Wash and in the Amargosa Desert. Shallowest static water levels in the latter areas generally are in Quaternary-Tertiary alluvium and playa sediments or Tertiary sedimentary rocks.

Hydrostratigraphic Units Stratabound aquifers and aquitards, as conceived by Winograd and Thordarson (1975), have long been the basis for discussions and numerical simulations of groundwater flow in the Death Valley region. However, this categorization fails to account for structurally and lithologically controlled variations in hydraulic properties within geologic units and vertical groundwater flow between geologic units of diverse lithology, which regionally are the prevailing influences on groundwater flow. Classifying related geologic units that have similar lithologic and hydraulic properties over laterally extensive areas as hydrostratigraphic units (HSUs) or hydrogeologic units (HGUs), instead of aquifers and aquitards, avoids misleading inferences about transmissive properties that do not persist on a regional scale.

8

A.L. Geldon

Figure 5. Lithofacies changes in Miocene volcanic rocks, Pahute Mesa to Yucca Mountain.

Unfortunately, there will never be universal agreement on hydrogeologic nomenclature in the Death Valley region, because the rationale for combining a large number of geologic units into a much smaller number of HSUs or HGUs will always depend on the purpose and scope of the study. Conceptual framework studies tend to have the smallest number of HSUs or HGUs, because these studies emphasize regional influences on groundwater flow. For example, Winograd and Thordarson (1975) identified 11 HGUs above Precambrian metamorphic and igneous “basement” rocks in the vicinity of the Nevada Test Site, whereas Laczniak et al. (1996) recognized only 9 equivalent HGUs. Studies such as this one or that of Belcher et al. (2001), which synthesize sparsely distributed hydraulic data to enable interpretations, require a small number of HSUs or HGUs to optimize available data

for detecting and discussing trends in the data. Both this study and that of Belcher et al. (2001) delineated 11 HSUs or HGUs, although units were defined somewhat differently in the two studies. Numerical modeling studies utilize simple or complex schemes of nomenclature that are commensurate with the model complexity. For example, D’Agnese et al. (1997) incorporated 10 HGUs into three model layers to simulate groundwater flow in the Death Valley region. In contrast, IT Corporation (1997a) constructed a groundwater flow model of the Death Valley region involving 26 HSUs distributed in 20 model layers. Geologists generally have tried to retain the largest number of established geologic units in developing hydrogeologic nomenclature for the Death Valley region. For example, Workman et al. (2002) incorporated 111 broadly defined geologic units into a geologic map

Implications for groundwater flow in the Southwest Nevada Volcanic Field

9

EXPLANATION Ground-water Basins and Sections (1) Pahute Mesa-Oasis Valley Basin a. Kawich Valley Section b. Oasis Valley Section (2) Ash Meadows Basin a. Pahranagat Valley Section b. Tikaboo Valley Section c. Indian Springs Valley Section d. Emigrant Valley Section e. Yucca-Frenchman Flat Section f. Specter Range Section (3) Alkali Flat-Furnace Creek Basin a. Fortymile Canyon Section b. Amargosa River Section c. Crater Flat Section d. Funeral Mountains Section Ground-water Flow Direction

Figure 6. Groundwater flow in the central Death Valley subregion. (Modified from D’Agnese et al., 1997.)

that was compiled to support groundwater modeling. Although this large number of units preserves genetic and structural complexity, insufficient data exist to quantify hydraulic properties of most of these map units. The map nomenclature will have to be simplified substantially for numerical modeling and other syntheses of hydraulic data. Eleven HSUs were recognized in this study for the purpose of discussing hydraulic properties in the Death Valley region. Table 3 lists these HSUs and compares nomenclature used in this study with nomenclature used in some previous hydrologic studies of the Death Valley region. Lithologic and hydrologic properties of HSUs identified in this study are described briefly below. Most basin-fill sediments are included in the QuaternaryTertiary fan, floodplain, and stream alluvium HSU. Component geologic units are Holocene to Pliocene in age. Included sediments consist of sand, gravelly sand, sandy gravel, and gravel, with cobbles, boulders, silty to clayey intervals, and thin interbeds of clay and silt, that were deposited mostly in alluvial fans,

floodplains, and stream channels. Subordinate eolian silt and sand, landslide deposits, debris flows, talus, colluvium, basalt flows, and tuff layers are present locally. Generally unconsolidated at and near the water table, sediments become more indurated with increasing depth. This HSU tends to be an aquifer regionally, but finer grained sediments and intercalated volcanics impede groundwater movement. The Quaternary-Tertiary playa and spring deposits HSU consists of playa, lake, marsh, and spring-deposited clay, marl, limestone, silt, sand, gravel, evaporite deposits, and thin tuff layers. Component geologic units are Holocene to Pliocene in age. Regionally, this HSU tends to be a confining unit, but limestone and sand layers can be very productive aquifers. The Quaternary-Tertiary basalt lava flows HSU consists of mafic lava flows intercalated with and underlying basin-fill sediments, and also cinder cones that are present locally in topographic basins. Component geologic units, which are Holocene to Miocene in age, are not laterally extensive. Hydraulic proper-

10

A.L. Geldon

Figure 7. Hydrogeologic section through the C-holes complex at Yucca Mountain, Nevada. (Section, location shown in Figure 39, is from Geldon et al., 1998.)

Figure 8. Static water levels and major transmissive intervals in Miocene tuffaceous rocks in boreholes drilled at Yucca Mountain. (Modified from Geldon, 1993.)

Implications for groundwater flow in the Southwest Nevada Volcanic Field 4085000

11

Bow Ridge Fault Yucca Wash Fault Sever Wash Fault WT6 1000 Midway Valley Fault 900 Pagany Wash Fault G2 800 Paintbrush Canyon Fault WT24 WT16 750775Fortymile Wash Fault Solitario Canyon WT18 Fault 735 H1 WT4 H5 WT15 B1 H6 WT14 H4 WT2 ONC1 C2P1 WT13 WT7 H3 WT1 G3

4080000

4075000

WT10

J13

WT17 WT3

Yucca Mountain

UTM NORTH, IN METERS

VH1 4070000

J11

WT12

WT11 Crater Flat

J12 18P

Southern Windy Wash Fault

4065000

4060000

Fortymile Wash

Stagecoach Road Fault

728

725

22PB 9SX

731 730

10P

1S 12PB

Jackass Flats 729

722 23P

3S

720 71519D

15P

5S

NEVADA TEST SITE

1X

2DB 710

4PB AD2AAMARGOSA VALLEY AD2

Highway 95 Fault 4055000

Amargosa Desert

4050000 535000

540000

545000

550000

555000

560000

565000

UTM EAST, IN METERS

EXPLANATION FAULT (Generally concealed partially by alluvium LINE OF EQUAL STATIC WATER LEVEL, IN METERS ABOVE MEAN SEA LEVEL—Contour interval variable APPROXIMATE DIRECTION OF GROUND-WATER FLOW Figure 9. Potentiometric surface in the Yucca Mountain area, 1996–2002. (Water-level data are from files of the U.S. Geological Survey and the Nye County Nuclear Waste Repository Project Office.)

No equivalent

Basalt of Crater Flat area, Basalt of Jackass Flats, Post–Thirsty Canyon basalt flows; Funeral Formation

Furnace Creek, Artist Drive, Muddy Creek, Horse Spring, and Pavits Spring Formations

Volcanics of Fortymile Canyon; Timber Mountain, Paintbrush, Crater Flat, and Belted Range Groups; Calico Hills and Wahmonie Formations

Tram Ridge Group; Tunnel Formation; Tuff of Yucca Flat; Tub Spring, Redrock Valley, Shingle Pass, Hiko, and Monotony Tuffs; Volcanics of Quartz Mountain; Tuff of Williams Ridge and Morey Peak

Tertiary, Cretaceous, and Jurassic intrusive rocks

Chinle, Moenkopi, Kaibab, and Toroweap Formations; Permian redbeds

Monte Cristo and Pogonip Groups; Guilmette, Nopah, Bonanza King, and Carrara Formations; Simonson, Sevy, Laketown, and Ely Springs Dolomites

Bird Spring, Eleana, Wood Canyon, and Johnnie Formations; Chainman Shale; Eureka, Zabriskie, and Stirling Quartzites; Pahrump Group

Early Proterozoic igneous and metamorphic rocks.

Quaternary-Tertiary basalt lava flows

Tertiary sedimentary rocks

Younger Tertiary tuff and lava flows

Older Tertiary tuff and lava flows

Tertiary and Mesozoic granitic rocks

Mesozoic and Permian sedimentary rocks

Paleozoic carbonate rocks

Paleozoic and Proterozoic clastic rocks

Early Proterozoic igneous and metamorphic rocks

No equivalent

Upper carbonate-rock aquifer, Eleana confining unit, Quartzite confining unit

Lower carbonate-rock aquifer

No equivalent

Granite

Tuff confining unit (locally welded tuff or lava flow aquifer)

Precambrian metamorphic rocks

Paleozoic-Precambrian clastic rocks

Paleozoic carbonate rocks

Mesozoic sedimentary and metavolcanic rocks

Tertiary–Late Jurassic granitic rocks

Tertiary volcanic rocks; Quaternary-Tertiary lava flows; Tertiary volcanic and volcaniclastic rocks

Tertiary volcanic rocks; Quaternary-Tertiary lava flows

Tertiary volcanic and volcaniclastic rocks

Quaternary-Tertiary lava flows

Quaternary playa deposits

Quaternary-Tertiary valley fill

D’Agnese et al. (1997)

IT Corporation (1997a)

No equivalent

Upper carbonate aquifer; Upper clastic confining unit; Lower clastic confining unit

Lower carbonate aquifer

No equivalent

Intrusives

Basal confining unit; Basal aquifer; Volcanic confining unit; Volcanics undifferentiated;

Timber Mountain aquifer; Tuff cones; Bullfrog confining unit; Belted Range aquifer; Volcanic aquifer

Tertiary sediments and Death Valley section

Volcanic aquifer; Volcanics undifferentiated

Alluvial aquifer

Alluvial aquifer

Hydrogeologic or Hydrostratigraphic Unit

Lava flow and welded tuff aquifers (locally tuff confining unit)

No equivalent

Valley-fill Aquifer

Quaternary-Tertiary lacustrine and playa sediments and spring-carbonate deposits

Laczniak et al. (1996) Valley-fill Aquifer

Quaternary-Tertiary playa and spring deposits

Representative Geologic Units

Quaternary stream-channel and floodplain alluvium; Quaternary-Tertiary fan alluvium

Quaternary-Tertiary fan, floodplain, and stream alluvium

(this report)

Hydrostratigraphic Unit

TABLE 3. HYDROSTRATIGRAPHIC UNITS, REPRESENTATIVE GEOLOGIC UNITS, AND CORRE LATIVE HYDROGEOLOGIC AND HYDROSTRATIGRAPHIC UNITS IN THE DEATH VALLEY REGION

12 A.L. Geldon

Implications for groundwater flow in the Southwest Nevada Volcanic Field ties of individual lava flows are extremely variable, and cinder cones typically are above the water table. The Younger Tertiary tuff and lava flows HSU consists of nonwelded to densely welded ash-flow tuff, depositional and fault-related tuff breccia, ash-fall tuff, reworked tuff, volcaniclastic rocks, and rhyolite, comendite, and trachyte lava flows. Component geologic units are Pliocene to Miocene in age. The volcanic rocks that comprise this HSU tend to have both fracture and matrix permeability. Fracturing, which is most intense near faults, is believed to enhance permeability. Alteration of rock-forming minerals to zeolite, clay, carbonate, silica, and other minerals, which is most intense toward eruptive centers, is believed to reduce permeability. Hydraulic properties within this HSU are extremely variable laterally and vertically. Fortuitous combinations of lithology and structure can result in very transmissive intervals or major impediments to groundwater flow over large areas. The Older Tertiary tuff and lava flows HSU consists mostly of ash-flow tuff, ash-fall tuff, reworked tuff, tuff breccia, volcaniclastic rocks, rhyolite, comendite, rhyodacite, and dacite lava flows, but shale, sandstone, and conglomerate are intercalated. Component geologic units are Miocene to Oligocene in age. The volcanic rocks that comprise this HSU tend to have both fracture and matrix permeability. Ash-flow tuffs tend to be nonwelded, but they can be partly to densely welded. Alteration of ash-flow, ash-fall, and reworked tuffs to zeolite, clay, carbonate, silica, and other minerals is common. Regionally, this HSU tends to be a confining unit. The Tertiary and Mesozoic granitic rocks HSU consists of granodiorite, quartz monzonite, granite, and tonalite stocks and larger plutons. Component geologic units are Oligocene to Jurassic in age. Although these intrusive rocks can produce small quantities of water from fractures and weathered zones, they impede groundwater flow wherever they are present. The Mesozoic and Permian sedimentary rocks HSU consists of interbedded conglomerate, gravelly sandstone, sandstone, siltstone, shale, calcareous shale, limestone, and gypsum. Component geologic units are Jurassic to Permian in age. Hydraulic properties are extremely variable. The Shinarump Conglomerate Member of the Chinle Formation and the Kaibab Limestone are regional aquifers, and other sandstone and limestone intervals transmit water locally. Conversely, intervals predominantly composed of shale, such as upper members of the Chinle Formation, are regional confining units. The Paleozoic carbonate rocks HSU interfingers with the Paleozoic and Proterozoic clastic rocks HSU. The Paleozoic carbonate rocks HSU consists of cherty, siliceous, silty, shaly, and fine-grained limestone and cherty, silty, sandy, and fine-grained dolomite with subordinate chert, shale, siltstone, sandstone, and quartzite. Component geologic units are Permian to Cambrian in age. Although clastic intervals confine flow, Mississippian, Devonian, Silurian, Ordovician, and Cambrian limestone and dolomite are aquifers throughout the Great Basin and adjacent physiographic provinces. The Paleozoic and Proterozoic clastic rocks HSU consists of argillite, shale, siltstone, quartzite, sandstone, and conglomerate

13

with subordinate chert, limestone, dolomite, and diabase. Component geologic units are Permian to Middle Proterozoic in age. Although limestone, dolomite, and clastic rocks locally transmit water, this HSU regionally is considered a confining unit. The Early Proterozoic igneous and metamorphic rocks HSU consists of schist, metaconglomerate, gneiss, marble, and metadiorite, which are intruded by monzonitic to granitic dikes. Although these rocks can produce small quantities of water from fractures and weathered zones, they constitute a confining unit that is the base of the groundwater flow system in the Death Valley region. The remainder of this report focuses on the Younger Tertiary tuff and lava flows HSU. This HSU at Yucca Mountain extends downward from the Rainier Mesa Tuff in the Timber Mountain Group to the Lithic Ridge Tuff in the Tram Ridge Group. This HSU at Pahute Mesa extends downward from the Volcanics of Stonewall Mountain to the Comendite of Split Ridge in the Belted Range Group. As indicated in Figure 10, this HSU is one of the most permeable in the Death Valley region. Groundwater in the Younger Tertiary Tuff and Lava Flows Hydrostratigraphic Unit Transmissive intervals in the Younger Tertiary tuff and lava flows HSU are bound not by stratigraphic or lithologic contacts but by terminations of vertically continuous fractures zones or, less commonly, zones with relatively large matrix permeability. Within these intervals, there is no correlation between the intensity of fracturing or the degree to which tuff layers are welded (Geldon, 1996, tables 4, 5, and 6). Whereas faults cutting the tuffaceous rocks commonly enhance their transmissivity (Geldon, 1996; Geldon et al., 1998), secondary zeolitization tends to inhibit flow through these rocks (Laczniak et al., 1996). In cross-hole hydraulic tests, the effective aquifer is the total thickness of transmissive intervals in the volume of rock between the production and observation wells. The upper and lower limits of the effective aquifer change depending on the interval that is open in the production well. Thus, for example, in an injection test conducted from June 11 to September 1, 1998 (Geldon et al., 1999), the injection well, UE-25 c#3, was open in the Prow Pass Tuff, the open interval between UE-25 c#3 and UE-25 ONC#1 is believed to have been open in the same interval, and the total thickness of transmissive rock between the two wells was estimated to be 19 m. In a pumping test conducted at Yucca Mountain from May 22 to June 1, 1995 (Geldon et al., 1998), the pumping well, UE-25 c#3, was open from the Calico Hills Formation to the Tram Tuff, the open interval between UE-25 c#3 and UE-25 ONC#1 is believed to have extended, also, from the Calico Hills Formation to the Tram Tuff, and the total thickness of transmissive rock between the two wells was estimated to be 176 m. Hypothetical flow paths between UE-25 c#3 and UE-25 ONC#1 in these two tests are shown in Figure 11. As shown in Figure 12, diverse rock types and fracture frequency, among other factors, impart layered heterogeneity to

14

A.L. Geldon 100 QUATERNARY-TERTIARY BASIN FILLSEDIMENTS

CUMULATIVE PERCENT EQUAL OR LESS THAN

90 YOUNGER TERTIARY TUFF AND LAVA

80

OLDER TERTIARY TUFF AND LAVA

70

TERTIARY-MESOZOIC GRANITIC ROCKS

60

MESOZOIC-PERMIAN SEDIMENTARY

50

PALEOZOIC CARBONATE ROCKS

40

PALEOZOICPROTEROZOIC CLASTIC ROCKS

GEOMETRIC MEAN

Figure 10. Log-normal distributions of hydraulic conductivity in Death Valley region hydrostratigraphic units. (Data from Appendix B.)

30 20 10 0 0.00001

0.0001

0.001

0.01

0.1

1

10

100

1000

HYDRAULIC CONDUCTIVITY, IN METERS PER DAY

the Younger Tertiary tuff and lava flows HSU. HSU boundaries are irrelevant for determining hydraulic conductivity, because hydraulic tests can be conducted in multiple combinations of variably transmissive intervals at any site within this HSU. The extent to which transmissive intervals can be traced laterally largely depends on the length, spacing, and interconnectivity of fractures. Tests in which tracers were injected into boreholes ER-20-6#1 and ER-20-6#2 in June 1997 and recovered in borehole ER-20-6#3 established the lateral continuity of transmissive intervals in rhyolite lava flows of the Calico Hills Formation on Pahute Mesa over distances of 89–131 m (IT Corporation, 1998b). Tests in which tracers were injected into boreholes UE-25 c#1 and UE-25 c#2 in 1996 and 1997 and recovered in borehole UE-25 c#3 established the lateral continuity of transmissive intervals in the Bullfrog and Tram Tuffs at Yucca Mountain over distances of 29–85 m (Fahy, 1997). Cross-hole seismic tomography confirmed that transmissive intervals in the Bullfrog and Tram Tuffs at Yucca Mountain extend 29 m between boreholes UE-25 c#2 and UE-25 c#3 (E. Majer, Lawrence Berkeley National Laboratory, 1993, written commun.) Regional groundwater flow between transmissive intervals is maintained by downward or upward hydraulic gradients. Vertical flow is enhanced by well-developed fracture networks related to regional structural fabrics. The principal structures affecting the Yucca Mountain area are a series of high-angle, north-northeasterly striking, extensional faults, including the Southern Windy Wash, Solitario Canyon, Stagecoach Road,

Ghost Dance, Bow Ridge, Midway Valley, Paintbrush Canyon, and Fortymile Wash Faults (most of these are shown in Fig. 9). Most fractures encountered in traverses of outcrops at Yucca Mountain are aligned with these faults (Geldon, 1993, Fig. 18), as are most fractures detected in boreholes (Fig. 13). Of secondary importance are northwesterly trending, predominantly right-lateral, strike-slip faults of the Walker Lane Belt (Carr, 1988), which include the Highway 95, Dune Wash, Drillhole Wash, Pagany Wash, Sever Wash, and Yucca Wash Faults, the Antler Wash Fault Zone, and the Las Vegas Valley Shear Zone (most of these are shown in Fig. 9). An overprint of Walker Lane tectonics is evident in the fracture frequency in boreholes UE-25 c#1 and UE-25 c#2 (Fig. 13). The coexistence of north-northeasterly and northwesterly faults and related fractures in the Yucca Mountain area imparts lateral (x-y) heterogeneity to the area. An example of this heterogeneity in a 21 km2 area was demonstrated by pumping borehole UE-25 c#3 at a rate of 17.9 L/s from May 22 to June 1, 1995. (This test is described fully by Geldon et al. [1998] and in more detail later in this report.) The pumping well, UE-25 c#3, was open in the Calico Hills Formation and the Prow Pass, Bullfrog, and Tram Tuffs. Six observation wells that were used in the test were open in formations ranging from the Topopah Spring Tuff down to the Lithic Ridge Tuff. The pattern of drawdown after 10 days clearly showed the influences of the two prominent fault sets. Drawdown in four wells that responded to pumping ranged from 0.072 to 0.42 m and was distributed along north-northeasterly and northwesterly trending axes (Fig. 14).

Implications for groundwater flow in the Southwest Nevada Volcanic Field

15

Figure 11. Hypothetical flow paths between the production well, UE-25 c#3, and an observation well, UE-25 ONC#1: (A) UE-25 c#3 open in the Prow Pass Tuff during an injection test in 1998; and (B), UE-25 c#3 open in the Calico Hills Formation and the Prow Pass, Bullfrog, and Tram Tuffs during a pumping test in 1995.

Drawdown in boreholes UE-25 c#2, UE-25 ONC-1, and USW H-4 decreased as a function of distance in a northwesterly direction. Drawdown in UE-25 c#1, north-northeast of, and about three times farther from the pumping well than UE-25 c#2, exhibited drawdown that was 26% larger than that in UE25 c#2. Plotted as a function of time, drawdown in UE-25 c#2, UE-25 ONC-1, and USW H-4 (Fig. 15) indicated horizontal hydraulic conductivity of 14 m/d in a northwesterly direction, whereas recovery in UE-25 c#1 (Fig. 16) indicated horizontal

hydraulic conductivity of 7 m/d in a north-northeasterly direction. The Antler Wash Fault Zone, in which boreholes UE-25 c#2, UE-25 ONC-1, and USW H-4 are present, is believed to have influenced drawdown in these observation wells. UE-25 c#1 might have been far enough from the Antler Wash Fault Zone that the Midway Valley Fault, which intersects UE-25 c#1, was the principal influence on drawdown in this well. Faults can act as either conduits or barriers to regional groundwater flow. A recharging fault conducts water between

16

A.L. Geldon

Figure 12. Lithologic and hydrologic heterogeneity in borehole UE-25 c#1 at Yucca Mountain. (Compiled from Geldon, 1993, 1996; Geldon et al., 2002.)

transmissive intervals on either side that have been brought into proximity by displacement of confining layers. The most prominent fault conduit in the Yucca Mountain area is the Midway Valley Fault (Fig. 9). Gravity and magnetic surveys and geologic mapping indicate that this high-angle, normal fault has ~40–60 m of down-to-the-west displacement (Simonds et al., 1995). The Midway Valley Fault intersects the Tram Tuff in boreholes UE-25 c#3 and UE-25 c#1 at Yucca Mountain. Pumping UE-25 c#3 at a rate of 26.8 L/s from October 30 to November 15, 1984 induced recharge from the Midway Valley Fault to the Tram Tuff in UE-25 c#1. This recharge is indicated in Figure 17 by the development of steady-state drawdown ~4500 min after pumping started. Recharge from the Midway Valley Fault dramatically affected drawdown in two observation wells during the lower Bullfrog pumping test, which was conducted May 8, 1996, to November 12, 1997, in borehole UE-25 c#3 (discussed by Geldon et al., 2002, and in more detail later in this report). Pump-

ing the lower Bullfrog interval in UE-25 c#3 at an average rate of 9.21 L/s produced drawdown in 11 observation wells located 29–6414 m away. Unlike the nine other observation wells that responded to pumping, boreholes USW H-4 and UE-25 WT#14 (Fig. 9) appear to have received a flux from a recharge boundary during the test. USW H-4, 2245 m northwest of UE-25 c#3, was open in the Prow Pass, Bullfrog, Tram, and Lithic Ridge Tuffs. UE-25 WT#14, 2249 m northeast of UE-25 c#3, is believed to have been connected hydraulically to UE-25 c#3 during the test through the Topopah Spring Tuff, Calico Hills Formation, Prow Pass Tuff, and Bullfrog Tuff. On June 27, 1996, after 72,000 min of pumping, drawdown in USW H-4, peaked at 0.21 m and then oscillated between 0.18 and 0.20 m at least through December 1996. After 72,000 min of pumping, drawdown in UE-25 WT#14 peaked at 0.15 m and then oscillated between 0.06 and 0.10 m at least through December 1996. An image-well solution (Walton, 1970)

Implications for groundwater flow in the Southwest Nevada Volcanic Field 240

T=

NUMBER OF FRACTURES

UE-25 c#1 200

Q × W (u ) 4πs

(1)

K = T/b

(2)

4Ttu r2

(3)

UE-25 c#2 160 120

S=

80 40 0 250-290

291-339

340-20

21-69

STRIKE AZIMUTH, IN DEGREES

Figure 13. Distribution of non-mineralized fractures in Yucca Mountain boreholes. (Data from Geldon, 1996.)

was applied to drawdown data for these two wells to obtain hydraulic properties. An image-well solution avoids overestimating transmissivity and hydraulic conductivity by removing recharge from the boundary which is superimposed on drawdown from pumping. Additionally, this solution was used to locate the boundary. In an image-well solution, the exponential integral curve of Theis (1935) is fit to drawdown data plotted as a function of time on log-log scales before and after boundary effects are observed for every observation well that exhibits these effects. Hydraulic properties are determined by applying the following equations to the pre-boundary match-point values:

where T is transmissivity (L2/T); Q is the discharge or injection rate (L3/T); W(u) is the exponential integral function; u is a dimensionless parameter defined by Equation 3; K is hydraulic conductivity (L/T); b is the transmissive thickness (L); S is storativity (dimensionless); t is the time since pumping or injection started or stopped corresponding to u; s is the water-level change (L) corresponding to W(u); and r is the distance from the test well to an observation well or the test well radius (L). Image well positions are located by solving the following equation for all observation wells exhibiting boundary effects: ri = r ×

p

(4)

0.40

05

0.05

i

WT#14

H-4

0.35

ONC-1

4076000

C#1 C#2

H-3

WT#13

0.30 0.25

5

0.20

4074000

0.

05

0.1

0.10 0.0

0.15

NW 5

0.10

WT#3 4072000 547000

(t t )

where: ri is the distance from the image well to the observation well (L); r is the distance from the pumped well to the observation well (L); tp is the time required to attain any value of drawdown, sp, before boundary effects are observed (T); and ti is the time required to attain a departure between the matched pre-boundary and post-boundary type curve traces equal to sp (T). For each observation well, a circle with radius ri is drawn with the observation well at the center. The intersection of two circles indicates two possible positions for the image well. The intersection of three circles indicates one possible position for the

0.

4078000

UTM NORTH (METERS)

17

NNE 549000

0.05

551000

553000

UTM EAST (METERS)

555000 DRAWDOWN, IN METERS

Figure 14. Asymmetric drawdown in observation wells at Yucca Mountain 14,000 min after pumping started in borehole UE-25 c#3 on May 22, 1995 (Data from Geldon et al., 1998).

1

18

A.L. Geldon

DRAWDOWN, IN METERS

Early-time Match point 0.1

Figure 15. Analysis of drawdown in observation wells by the method of Neuman (1975), pumping test in UE-25 c#3, Yucca Mountain, May 22–June 1, 1995. (Data from Geldon et al., 1998.)

USW H-4 0.01

UE-25 ONC#1 UE-25 c#2 UE-25 c#1 TYPE CURVE

0.001 0.0001

0.001

0.01

0.1

1

10

100

TIME SINCE PUMPING STARTED/DISTANCE SQUARED, IN MINUTES PER SQUARE METER

1

RECOVERY, IN MINUTES

Early-time Match point 0.1

+

+

Late-time Match Point

Figure 16. Analysis of recovery in borehole UE-25 c#1, June 1–9, 1995, by the method of Neuman (1975), pumping test in UE-25 c#3, Yucca Mountain, May 22– June 1, 1995 (Geldon et al., 1998).

0.01 DATA TYPE CURVE

0.001 1

10

100

1000

10000

100000

TIME SINCE PUMPING STOPPED, IN MINUTES

DRAWDOWN, IN METERS

10

1

Figure 17. Analysis of drawdown in the Tram Tuff interval in borehole UE-25 c#1 caused by pumping borehole UE-25 c#3 October 30–November 15, 1984. (Modified from Geldon, 1996.)

Match Point 0.1

Transmissivity = 730 m2/d Hydraulic conductivity = 12 m/d Storativity = 0.003 Analyzed by method of Cooper (1963)

DATA TYPE CURVE

0.01 1

10

100

1000

10000

TIME SINCE PUMPING STARTED, IN MINUTES

100000

Implications for groundwater flow in the Southwest Nevada Volcanic Field image well. The boundary is located at half the distance between the image well and the pumped well. For USW H-4 and UE-25 WT#14, Theis (1935) curves were matched to the drawdown data before 30,000 min and from 30,000 to 300,000 min. Figure 18 shows the analytical solution for USW H-4. Equations 1–3 applied to early-time match points indicated transmissivity of 560–710 m2/d, hydraulic conductivity of 4.2–5.0 m/d, and storativity of 0.002. Equation 4 applied to values of tp and ti indicated that image wells were located 4762 m from USW H-4 and 3681 m from UE25 WT#14. Circles with a radius of 4.8 km centered on USW H-4 and a radius of 3.7 km centered on UE-25 WT#14 were drawn on the 1:24,000-scale geologic map of Day et al. (1998). The two circles intersected at the southern end of Fran Ridge and at the juncture of Midway Valley and Yucca Wash (Fig. 19). Because USW H-4 and UE-25 WT#14 are north of the pumping well, UE-25 c#3, the juncture of Midway Valley and Yucca Wash, also north of UE-25 c#3, is the more likely of the two intersections for the location of the image well. By definition, the boundary is half the distance between the image well and the pumping well. This solution indicated that the recharge boundary is the Midway Valley Fault zone, 2713 m northeast of UE-25 c#3. Faults act as barriers to regional groundwater flow where transmissive intervals are offset against non-transmissive intervals. One of the most prominent barrier-boundary faults in the Yucca Mountain area is the Solitario Canyon Fault (Figs. 9 and

19

19), which dips ~70° westward. Bedrock displacement along this fault ranges from 61 m down to the east at its northern end to >500 m down to the west at its southern end (Simonds et al., 1995). Primarily, barrier-boundary faults segment the Alkali Flat–Furnace Creek and Ash Meadows groundwater basins (Fig. 6) into separate hydrologic domains. Extensive hydraulic testing conducted at Yucca Mountain from 1995 to 1998 had no effect on water levels in production wells located in Jackass Flats to the east (Fig. 6). This observation appears to indicate that Yucca Mountain and Jackass Flats are located in separate hydrologic domains. In fact, potentiometric contours, geophysical lineaments, and pumping-test data indicate that hydrologic boundaries isolate Yucca Mountain on all sides. Faults coincide with all boundaries of the Yucca Mountain hydrologic domain. Faults bounding the northern part of this hydrologic domain are shown in Figure 20. The west side of the Yucca Mountain hydrologic domain is demarcated by the north-northeasterly trending Solitario Canyon and Southern Windy Wash Faults, both of which dip steeply westward and have mostly down-to-the-west displacement (Simonds et al., 1995). Steepened hydraulic gradients across the Solitario Canyon and Southern Windy Wash Faults (Fig. 9) indicate that these faults inhibit groundwater flow. At the south end of Yucca Mountain, the Southern Windy Wash Fault is a barrier to flow because it offsets transmissive welded tuff and tuff breccia in the Rainier Mesa and Tiva Canyon Tuffs against non-transmissive

1 s i = 0.1 m t i = 90,000 minutes

DRAWDOWN, IN METERS

MATCH POINT 0.1

sp = 0.1 m t p = 20,000 minutes

Figure 18. Analysis of drawdown in USW H-4, pumping test in UE-25 c#3, May 8, 1996, to November 12, 1997. (Data from Geldon et al., 2002.)

0.01 DATA EARLY-TIME W(u) TYPE CURVE LATE-TIME W(u) TYPE CURVE

0.001 1000

10000

100000

TIME SINCE PUMPING STARTED, IN MINUTES

1000000

20

A.L. Geldon

116°27′30″

116°26′00″ EXPLANATION

H-4 –USW H-4 C#3 –UE-25 c#3 WT#14 - UE-25 WT#14 M – Midway Valley Fault F – Fortymile Wash Fault S – Solitario Canyon Fault

Pinnacles Ridge

Yucca Wash

WT#14

36°52′30″

Midway Valley M H-4

Yucca Mountain

WT#14 C#3 Fran Ridge

S 36°47′30″

F Busted Butte

Fortymile Wash

BOREHOLE CIRCLE WITH RADIUS EQUAL TO DISTANCE BETWEEN OBSERVATION AND IMAGE WELLS FAULT DISTANCE BETWEEN IMAGE AND PUMPING WELLS - Cross at recharge boundary

Figure 19. Identification of the Midway Valley Fault as a recharge boundary by an image well solution of a pumping test conducted in UE-25 c#3 at Yucca Mountain, May 8, 1996, to November 12, 1997.

Implications for groundwater flow in the Southwest Nevada Volcanic Field

116°27′30″

21

116°26′00″

EXPLANATION WELL ABBREVIATIONS

YUCCA WASH FAULT

G-2 WT#16

36°52′30″

PAGANY WASH FAULT

H-1

WT#4

H-5 DRILL HOLE WASH

H-6

YUCCA MOUNTAIN WT-7

H-3

ALICE POINT

B#1 MIDWAY VALLEY WT#14 H-4

ONC#1 C#3 WT-1

WT#13

C#1 C#2

FRAN BOW RIDGE RIDGE

WT-10

DUNE WASH

36°47′30″

WT-11

WT#15

FORTYMILE WASH J-13

WT#3

BUSTED BUTTE

G-2 - USW G-2 H-1 - USW H-1 H-3 - USW H-3 H-4 - USW H-4 H-5 - USW H-5 H-6 - USW H-6 B#1 - UE-25 b#1 C#1 - UE-25 c#1 C#2 - UE-25 c#2 C#3 - UE-25 c#3 ONC#1 - UE-25 ONC#1 WT-1 - USW WT-1 WT#3 - UE-25 WT#3 WT#4 - UE-25 WT#4 WT-7 - USW WT-7 WT-10 - USW WT-10 WT-11 - USW WT-11 WT#13 - UE-25 WT#13 WT#14 - UE-25 WT#14 WT#15 - UE-25 WT#15 WT#16 - UE-25 WT#16 FAULT BOUNDARY

ONC#1

JACKASS FLATS

J-12

J-13 SOLITARIO CANYON FAULT

FORTYMILE WASH FAULT

BOREHOLE WITH DRAWDOWN IN 1996-97 PUMPING TEST IN UE-25 c#3

BOREHOLE WITH NO DRAWDOWN IN 1996-97 PUMPING TEST IN UE-25 c#3

Figure 20. Boundaries of the northern Yucca Mountain hydrologic domain, as indicated by a pumping test conducted in borehole UE-25 c#3 May 8, 1996 to November 12, 1997. (Data from Geldon et al., 2002.)

22

A.L. Geldon

Tertiary sedimentary rocks and a bedded interval in the Bullfrog Tuff (Fig. 21). The northern boundary of the Yucca Mountain hydrologic domain is demarcated by the en echelon, northwesterly trending Yucca Wash, Sever Wash, and Pagany Wash Faults, which dip steeply to the southwest and exhibit predominantly strike-slip displacement (Simonds et al., 1995). A large hydraulic gradient in the regional potentiometric surface extends across the area where these faults are present (Fig. 9). Fridrich et al. (1994) interpreted this large hydraulic gradient to be the result of a buried fault at the interface between Paleozoic clastic and carbonate rocks that diverts water recharged to the volcanic rocks north of the fault into the more permeable Paleozoic carbonate rocks

south of the fault. This interpretation is supported by a negative heat-flow anomaly in the vicinity of the large hydraulic gradient, which was discussed by Sass et al. (1988). The east side of the Yucca Mountain hydrologic domain is a poorly delimited graben that follows the trend of Fortymile Wash from Yucca Wash to the town of Amargosa Valley, Nevada. At its northern end, this graben probably includes two faults shown on a geologic map by Day et al. (1998), a concealed fault in Fortymile Wash east of Alice Point, and the Busted Butte Fault. Electrical resistivity and gravity data indicate additional segments of this graben on both sides of Fortymile Wash (Ponce and Oliver, 1995). Offsets of Tertiary volcanic and sedimentary rocks between wells NC-EWDP-15P and NC-Washburn 1x establish

Figure 21. Geologic section across the southern end of Yucca Mountain north of U.S. 95. (Interpreted from Nye County Nuclear Waste Repository Project Office borehole lithologic logs available at http://www.nyecounty.com/.)

Implications for groundwater flow in the Southwest Nevada Volcanic Field the location of the “Fortymile Wash Graben” at the southeastern end of Yucca Mountain (Fig. 21). Step-like decreases in the water table across faults bounding the graben (Fig. 21) indicate that these faults inhibit groundwater flow across them. The south side of the Yucca Mountain hydrologic domain is inferred to be the broad, complex Highway 95 Fault zone, which extends northwesterly along the Nevada-California state line from Pahrump Valley to the southern Amargosa Desert and exhibits predominantly strike-slip displacement (Blakely et al., 1999). A southward 44 m decrease in static water levels between wells NCEWDP-9SX and NC-EWDP-12PB, which straddle the Highway 95 Fault zone at the southwestern end of Yucca Mountain, indicates that the fault zone inhibits groundwater flow across it.

23

North of the Yucca Mountain hydrologic domain, northnortheasterly trending, high-angle, extensional faults and the structural walls of overlapping caldera complexes disturb regional groundwater flow (Laczniak et al., 1996; Blankennagel and Weir, 1973). The north-northeasterly trending, high-angle faults can act as either barriers or conduits, depending on how they offset transmissive and non-transmissive volcanic rocks. Different sequences of lava flows and tuff emplaced within individual calderas and faults associated with caldera walls impede groundwater flow. The Ammonia Tanks and Rainier Mesa calderas (Fig. 22) probably cause limited hydraulic connection between Pahute Mesa and areas to the south (Laczniak et al., 1996).

Figure 22. Generalized geologic map of the Southwest Nevada Volcanic Field between Yucca Mountain and Pahute Mesa, showing caldera complexes and related volcanic rocks. (Modified from Fleck et al., 1996.)

24

A.L. Geldon

HYDRAULIC TESTS Despite the complexity of the groundwater system in the eastern Southwest Nevada Volcanic Field, extensive hydraulic testing has been done there successfully for nearly 50 years. Hydraulic testing in the area evolved over the years from window-of-opportunity efforts during drilling of exploration, monitoring, and emplacement boreholes for nuclear tests to systematic, multidisciplinary approaches in boreholes dedicated for hydrologic research. Planning of the later tests benefited from the knowledge of what worked and what did not in the earlier tests. Whereas identification of transmissive intervals initially relied on crude lithologic logs and relative specific-capacity profiling, it became standard practice to use detailed borehole lithologic and geophysical logs and increasingly refined borehole flowsurvey techniques in this effort. Ongoing geologic mapping at increasingly larger scales, together with petrographic correlation of a growing number of borehole lithologic logs and repeated refinements of stratigraphic nomenclature for Tertiary volcanic

rocks supported the planning and analysis of hydraulic tests. As more funding became available for hydraulic testing, down-hole pressure transducers replaced steel and electric tapes for obtaining borehole water levels, and sophisticated flowmeters replaced weirs, flumes, and buckets for measuring borehole discharge. Electronic data loggers and computers replaced notebooks for data acquisition and storage. Continuing development of analytical methods has made it possible to analyze both newly obtained and previously published hydraulic-test data consistently with diverse hydrogeologic settings and to produce increasingly accurate determinations of hydraulic properties. Hydraulic-test data for the Younger Tertiary tuff and lava flows HSU were obtained from 41 sites in the eastern Southwest Nevada Volcanic Field, which are shown in Figure 23. Well Completion and Instrumentation Most of the wells shown in Figure 23 were drilled by airrotary, reverse-rotary, and hydraulic-rotary methods (Table 4).

Figure 23. Pumping, injection, and observation wells used in tests which provided hydraulic properties of the Younger Tertiary tuff and lava flows hydrostratigraphic unit at Pahute Mesa, Yucca Mountain, Timber Mountain, Frenchman Flat, and Yucca Flat.

UTM COORDINATES, IN METERS, SHOWN ON AXES

+ TEST WELL

710 920.2 898.2 897.6 855.6 1525.2 2587.4 1830.3 2118.4 2287.8 2438.4 1371.6 1277.7 1369.2 1949.2 4171.5 762.2 1219.8

1097.7

1099.0

1302.1

1774.8

1973.5

1973.6

1970.8

1688.0 2143.7

2108.9

2052.9

2048.0

2084.5

1972.7

1905.6

1905.9

1919.3

1864.3

1199.2

1200.7

WW-4 (Gillespie et al., 1996)

WW-4a (Gillespie et al., 1996)

UE-2aw (USGS, unpublished data) PM-3 (Kilroy and Savard, 1996) ER-20–6#1 (IT Corporation, 1998a) ER-20–6#2 (IT Corporation, 1998a) ER-20–6#3 (IT Corporation, 1998a) UE-18r (Carr et al., 1981) UE-19c (Blankennagel and Weir, 1965) UE-19e (Blankennagel and Weir, 1965) UE-19fs (Blankennagel and Weir, 1973) UE-19 gs (Blankennagel and Weir, 1965) UE-19i (Blankennagel and Weir, 1965) U-20a-2 WW (Blankennagel and Weir, 1973) U-20d (Orkild and Jenkins, 1978) UE-20d (Blankennagel and Weir, 1973) UE-20e-1 (Blankennagel and Weir, 1965) UE-20f (Blankennagel and Weir, 1965) UE-25 a#1 (Spengler and others, 1979) UE-25 b#1 (Lahoud et al., 1984)

457.8

447.4

1063.1

1011.5

Well and source of data

J-13 (Thordarson 1983)

Depth (m)

LSD (m AMSL) Drilling method

Air rotary

Hydraulic rotary

Air rotary

Air rotary

Air rotary

Unknown

Air rotary

Air rotary

Hydraulic rotary

Air rotary

Air rotary

Unknown Air rotary

Air rotary

Mud rotary and air rotary Air rotary

Hydraulic rotary

Unknown

Reverse rotary

Air rotary

Hydraulic rotary and air rotary

91–22

44–8

66–16

66–16

66–24

No Data

66–27

66–25

66–25

66–22

66–25

No Data 66–25

76–31

61–31

44–31

61–25

34–31

122–52

91–51

66–19

Hole diameter (cm) Casing

Cased to 518 m

Cased to 8.5 m

Cased to 1,358 m

Cased to 457 m

Cased to 746 m

No Data

Cased to 262 m

Cased to 883 m

Cased to 808 m

Cased to 782 m

Cased to 754 m

Cased to 496 m Cased to 738 m

Cased to 855 m

Cased to 894 m

Cased to 891 m

Cased to 449 m

Cased to 23 m

Cased to 458 m

Cased to 438 m

Cased to 1,032 m

51–31

34

51–24

51–34

51–27

No Data

46–34

51–34

51–34

51–34

51–34

27 50–32

51–14

34–14

34–14

41–27

No Data

91–34

78–34

46–14

Casing diameter (cm)

Cemented to 89 m

Cemented to bottom of casing

Cemented to bottom of casing

Cemented to bottom of casing

Cemented to bottom of casing

No Data

Cemented to bottom of casing

Cemented to bottom of casing

Cemented to bottom of casing

Cemented to bottom of casing

Cemented to bottom of casing

Cemented to bottom of casing Cemented to bottom of casing

Cemented to top of well screen

Mostly cemented to top of well screen Cemented to top of well screen

Cemented to bottom of casing

Casing apparently uncemented

Cemented to 34 m

Cemented to 132 m and partly cemented between sections of perforated casing Cemented to 163 m

Seals

TABLE 4. COMPLETION DATA FOR WELLS USED IN HYDRAULIC TESTS OF THE YOUNGER TERTIARY TUFF AND LAVA FLOWS HSU, YUCCA MOUNTAIN, PAHUTE MESA, AND ADJACENT AREAS

Openings

(continued)

Casing perforated 477–508 m; open hole below 518 m

Open hole below 8.5 m

Open hole below 1358 m

Open hole below 457 m

Open hole below 746 m

No Data

Open hole below 262 m

Open hole below 883 m

Open hole below 808 m

Open hole below 782 m

Open hole below 754 m

Well screen 743–891 m, open hole below Well screen 736–894 m, open hole below Well screen 742–855 m, open hole below Open hole below 496 m Open hole below 738 m

Open hole below 449 m

Casing perforated 304–422 m and 820–1010 m; open hole below 1032 m Casing perforated 287–438 m; open hole below Casing slotted 325–390 m and 416–444 m; open hole below 458 m Open hole below 23 m

Implications for groundwater flow in the Southwest Nevada Volcanic Field 25

1828.8

1132.4

1114.2

1303.0

UE-25 c#2 (Geldon, 1993)

UE-25 c#3 (Geldon, 1993)

UE-25 p#1 (Craig and Robison, 1984) USW H-1 (Rush et al., 1984)

514.8 348.1 481.6 440.7 398.7 399.3 762.0

762.3

1030.1

1169.2

1094.1

1074.7

1076.0

798.3

963.2

469.2

1162.8

1201.1

1,219.9

1,219.2

1478.9

1302.1

1,219.2

914.7

1269.6

1248.7

1830.6 1219.2

1533.9 1483.2

914.4

914.4

Air rotary

Unknown

Air rotary

Air rotary

Air rotary

Air rotary

Air rotary

Dual-wall percussion and reverse-rotary Air rotary

Air rotary

Air rotary

Air rotary

Air rotary

Air rotary Air rotary

Air rotary

Air rotary

Air rotary

Air rotary

Air rotary

Drilling method

31–16

46–21

38–22

38–22

38–22

38–22

122–22

66–22

31–12

91–22

91–22

91–22

44–22

44–8 91–22

122–22

76–25

122–25

91–25

91–22

Hole diameter (cm)

Cased to 278 m

Cased to 121 m

Cased to 37 m

Cased to 21 m

Cased to 14 m

Cased to 15 m

Cased to 12 m

Cased to 10 m

Cased to 134 m

Cased to 581 m

Cased to 788 m

Cased to 560 m

Cased to 615 m

Cased to 242 m Cased to 792 m

Cased to 687 m

Cased to 1,197 m

Cased to 403 m

Cased to 415 m

Cased to 415 m

Casing

24–19

17

27

27

27

27

41–27

27

22–14

76–27

76–27

76–27

34–24

34–24 76–25

78–24

61–41

76–27

76–27

76–27

Casing diameter (cm) Seals

Cemented to 16 m and at bottom of casing

Casing apparently uncemented

Cemented to bottom of casing

Cemented to bottom of casing

Cemented to bottom of casing

Cemented to bottom of casing

Cemented to bottom of casing

Cemented to bottom of casing

Cemented to 95 m and 562– 581 m Cemented to 11 m; 8 packers between 134 and 453 m

Cemented to 95 m and 548– 560 m Cemented to 95 m and 783– 788 m

Cemented to 85 m Cemented to 38 m and at bottom of casing Cemented to 12 m and at bottom of casing

Cemented to 112 m and 394–418 m Cemented to 98 m and 398– 416 m Cemented to 96 m and 391– 417 m Cemented to 99 m and at bottom of casing Cemented to 102 m and at bottom of casing

Openings

Open hole below 278 m

Open hole below 121 m

Open hole below 37 m

Open hole below 21 m

Open hole below 14 m

Open hole below 15 m

Open hole below 12 m

Open hole below 10 m

Casing perforated 572–673 m; open hole below 687 m until 1982; modified after 1982 Open hole below 242 m Casing perforated 754–792 m; open hole below Casing perforated 549–567 m and 594–600 m; open hole below 615 m Casing perforated 533–540 m; open hole below 560 m Casing perforated 707–712 m and 718–782 m; open hole below 788 m Casing perforated 530–562 m; open hole below 581 m Open hole below 453 m

Open hole below 1197 m

Open hole below 417 m

Open hole below 416 m

Open hole below 418 m

Note : Observation wells that did not respond to tests are not listed; LSD—land surface datum (altitude); AMSL—above mean sea level. NWRPO— Nuclear Waste Repository Project Office.

USW WT-1 (Nelson et al., 1991) UE-25 WT#3 (Nelson et al., 1991) UE-25 WT#4 (Nelson et al., 1991) USW WT-11 (Nelson et al., 1991) UE-25 WT#12 (O’Brien, 1997) UE-25 WT#14 (Nelson et al., 1991) NC-EWDP-3D (Questa Engineering Corporation, 1999) USW VH-1 (Thordarson and Howells, 1987)

USW H-6 (Craig and Reed, 1991) UE-25 ONC#1 (Nye County NWRPO, 1995)

USW H-4 (Whitfield et al., 1985) USW H-5 (Robison and Craig, 1991)

USW G-2 (O’Brien, 1998) USW H-3 (Thordarson et al., 1985) USW G-4 (Lobmeyer 1986)

1805.3

1132.2

UE-25 c#1 (Geldon, 1993)

914.4

1130.6

Well and source of data

Depth (m)

LSD (m AMSL)

TABLE 4. COMPLETION DATA FOR WELLS USED IN HYDRAULIC TESTS OF THE YOUNGER TERTIARY TUFF AND LAVA FLOWS HSU, YUCCA MOUNTAIN, PAHUTE MESA, AND ADJACENT AREAS (continued)

26 A.L. Geldon

Implications for groundwater flow in the Southwest Nevada Volcanic Field Core-drilling was done in selected intervals to provide samples for laboratory determinations of mineralogy, porosity, permeability, bulk density, and other physical properties. Generally, a mixture of air and foam was used as the drilling fluid to make details of borehole walls visible to geophysical logs, to facilitate detection of the static water level, and to avoid contaminating the chemistry of potential water samples. As a check against contamination of samples by drilling fluid, lithium chloride tracer commonly was added to the drilling fluid (Geldon, 1993). Samples considered to be representative of formation water were not collected until lithium concentrations approached natural concentrations in water used during drilling and completion of the well. Also, the point at which lithium concentrations in the injection and discharge lines diverged could be interpreted to indicate the static water level, which was necessary to know for making decisions about well completion, geophysical logging, and testing while advancing the well to its final depth. In general, holes were started with large-diameter drill bits to accommodate emplacement of surface casing and a cement seal. Holes and casing were telescoped downward, until the hole diameter desired for potential test intervals was reached (Table 4). The targeted hole diameter typically was between 16 and 31 cm. Casing typically was extended a few meters to tens of meters below the static water level. Relatively few holes were cased their entire length. In those holes, sections of perforated casing, slotted casing, or well screen were emplaced opposite known transmissive intervals. Many holes were cemented to the bottom of casing, but it was more common to emplace cement to 100 m or less and tack-cement the bottom of casing. Geophysical logs were run in most boreholes, usually before and during hydraulic tests to: (1) provide details about borehole construction; (2) refine geologic contacts; (3) correlate geologic units among boreholes; (4) determine the depth of fracture and fault zones; (5) determine the strike and dip of fractures, faults, and bedding; (6) determine physical properties of rocks; and (7) locate transmissive intervals (Blankennagel, 1967; Keys, 1988; Hess, 1990). Gyroscopic logs indicate the extent to which boreholes deviate from a vertical axis. Caliper logs indicate enlarged sections of borehole (commonly associated with fracture zones) and constrictions (caused by caving of unstable rock). Temperature logs show the thermal gradient in a borehole, and deflections in this gradient indicate where water is flowing into or out of the borehole. Flow surveys locate transmissive and non-transmissive intervals in a borehole Induction, focused, and dielectric resistivity logs indicate permeable, water-yielding intervals, changes in effective porosity, and zones of zeolitic or argillic alteration. Borehole-compensated gamma-gamma logs and epithermal neutron logs indicate primary and secondary porosity, whereas acoustic logs are not sensitive to fractures and indicate only primary porosity. Porosity values determined from gamma-gamma and acoustic logs can be used to calculate the bulk modulus of elasticity and specific storage. Acoustic televiewer and television camera logs can detect strikes and dips of fractures, partings, and geologic contacts where boreholes are

27

free of turbid drilling fluid. Many other geophysical logs were run in boreholes within the study area, but time and experience demonstrated that these logs were useless or marginally useful, and they are not discussed. In the early days, slug-injection and swabbing recovery tests were considered more useful than pumping tests for determining hydraulic properties. Consequently, a short (1–2 day), crude, constant-rate pumping test preceded slug-injection and swabbing recovery tests in most of the earlier boreholes. With time and experience, constant-rate pumping tests were found to be more accurate than slug-injection and swabbing recovery tests, and the test sequence was reversed to enable results of the slug-injection and swabbing recovery tests to be used for planning and analyzing the pumping tests. In the early days, most pumping tests were conducted between the bottom of casing and the bottom of the hole, but modern testing methods usually employ some combination of straddle packers, well screens, and perforated casing to isolate one or more test intervals in a borehole. Modern pumping tests typically use sophisticated electronic and mechanical equipment, such as pressure transducers, flow meters, and barometers. Pumps, packers, and pressure transducers are suspended on drill tubing to target intervals in these tests. With an understanding that the test design can influence the shape of the drawdown curve (Fig. 24) and, hence, the determination of hydraulic properties, 1–2 weeks commonly is allowed in modern pumping tests to develop the full drawdown curve. With the recognition that drawdown in the pumping well is influenced strongly by turbulence near the well, damage to borehole walls by drilling, pump placement, and other factors not related to physical properties of the rock being tested (Kruseman and de Ridder, 1983), cross-hole pumping tests using observation wells have been conducted at four sites since 1980. Results of hydraulic tests in the eastern Southwest Nevada Volcanic Field were compiled for this study to provide a representative distribution of hydraulic properties within the Younger Tertiary tuff and lava flows HSU. The hydraulicproperty database for this HSU contains 86 analyses from 41 withdrawal, injection, and observation wells (Fig. 25). This database includes 40 published hydraulic test results, 36 revised analyses of published hydraulic test results, and 10 analyses of recently collected and archived data that have never been published. All hydraulic-test results compiled from published reports were verified by independent analytical solutions appropriate for the hydrogeologic setting in which these tests were conducted. Some previously published hydraulic test results were excluded from the database, because careful evaluation of these test results indicated problems either in test design or data collection that made data analyses suspect. Some analyses in the database are the combined results of several individual analyses. For, example, in UE-25 b#1 and other wells with several slug-injection tests conducted in the same geologic unit, transmissivity values determined from individual tests were added, and hydraulic conductivity values determined from individual tests were averaged to provide single values

28

A.L. Geldon

DRAWDOWN, IN CENTIMETERS

100

10

Figure 24. Changes in drawdown trends in the lower Bullfrog interval of borehole UE-25 c#1 as a function of the rate and duration of pumping.

June 1995, 22.5 L/s (Confined) February 1996, 8.5 L/s (Leaky confined) May 1996, 9.5L/s (Dual permeability) 1 1

10

100

1000

10000

100000

1000000

TIME SINCE PUMPING STARTED, IN MINUTES

40 NEW ANALYSES

NUMBER OF ANALYSES

35

REVISED ANALYSES PUBLISHED ANALYSES

30

25

20

Figure 25. Distribution of hydraulic-test data for the Younger Tertiary tuff and lava flows hydrostratigraphic unit in the vicinity of Pahute Mesa and Yucca Mountain. (Data in Appendix B.)

15

10

5

0 Cross-hole, Cross-hole, Cross-hole, Single-well, Single-well, constant-rate constant-rate constant-rate constant-rate slug-injection pumping injection airlift pumping

Single-well, swabbingrecovery

TEST TYPE

of transmissivity and hydraulic conductivity for the geologic unit. For many wells in the study area that were open in several geologic units, such as PM-3, pumping tests were first analyzed to determine the composite transmissivity of the open part of the well. Transmissivity and hydraulic conductivity were then apportioned among geologic units open to the well using flow survey data and results of slug-injection and swabbing tests (as described in the next section).

Flow Distribution in Boreholes Boreholes completed in volcanic rocks in the study area typically are open in both transmissive and non-transmissive intervals that encompass several rock types and, commonly, more than one geologic formation. Figure 26 shows two borehole flow surveys that unequivocally demonstrate the occurrence of flow from discrete intervals in Tertiary volcanic rocks at Pahute Mesa and Yucca

Implications for groundwater flow in the Southwest Nevada Volcanic Field

760

DEPTH BELOW LAND SURFACE, IN METERS

B A

BULLFROG TUFF TRAM TUFF

860

DEPTH, IN METERS

960 1060 1160 DEADHORSE FLAT FORMATION 1260 1360 1460 1560 1660 TRACHYTE OF MUENSTER

1760

440

29

Static Water Level

500

Calico Hills Formation

560 620 Prow Pass Tuff 680 740 Bullfrog Tuff

800 860 920

Tram Tuff

GROUSE CANYON TUFF 0

10

20

30

40

50

60

70

80

90

100

FLOW, IN PERCENT

0

10

20

30

40

50

60

70

80

90

100

FLOW, IN PERCENT

Figure 26. Tracejector flow surveys in (A) borehole UE-19e, Pahute Mesa, August 31, 1964 and (B) UE-25 b#1, Yucca Mountain, August 1981 (Lahoud et al., 1984; Thordarson and Rush, unpublished U.S. Geological Survey report available through GSA Data Repository; see footnote 1).

Mountain. As indicated in Figure 26, transmissive intervals typically represent a small proportion of the open part of a borehole. Borehole flow survey techniques used in the study area have included (1) tracejector flow surveys (Blankennagel, 1967); (2) spinner flow surveys (Blankennagel, 1967); (3) heat-pulse flowmeter surveys (Hess, 1990); and (4) oxygen-activation flow surveys. Although flow surveys are the most direct indicators of the distribution of transmissive intervals in a borehole, they are not precise. Different types of flow surveys conducted in the same borehole can indicate similar but slightly different distributions of transmissivity (Fig. 27). In addition to flow surveys, a variety of techniques has been used in the study area to identify transmissive intervals in boreholes completed in Tertiary volcanic rocks. These techniques have included (1) drilling production logs; (2) relative specific capacity profiles determined from slug-injection and swabbingrecovery tests; (3) temperature logs; (4) resistivity logs, used with temperature, acoustic televiewer, television, and caliper logs; and (5) lithologic logs, used together with other indicators or alone. Specific methods used to identify transmissive intervals in individual boreholes depended on the funding and the understanding of the efficacy of different methods available at the time that hydraulic tests were conducted in them. When a sufficient number of slug-injection and swabbingrecovery tests are done to cover all or most of the open interval of a borehole, quantitative analyses of these tests, together with lithologic and geophysical logs, can be used to compile a hydraulicconductivity profile of the open interval. Geldon (1996) showed that hydraulic properties determined from slug-injection tests are comparable to hydraulic properties determined from analyses of pumping-well drawdown. Figure 28 shows a typical design for slug-injection tests conducted in the study area. Figure 12 shows a profile of hydraulic-conductivity in borehole UE-25 c#1, from

the Calico Hills Formation to the Tram Tuff, which was developed from 20 slug-injection tests. Complete hydraulic conductivity profiles for the open interval of a borehole based on slug-injection and swabbing-recovery tests would not be possible if many of the tests attempted in the interval were unsuccessful. These tests can fail because of mechanical problems, such as leakage around packers, but they also can be unsuccessful when head recovery is so rapid that it cannot be recorded or analyzed. Because head recovers most rapidly in the most transmissive intervals, slug-injection and swabbing-recovery tests cannot be used to determine hydraulic properties of the most transmissive intervals open to a borehole. Depending on the injection tool, the upper limit of transmissivity restricting the use of these tests is 5–10 m2/d (Craig and Robison, 1984; Lahoud et al., 1984). The relative specific capacity distribution determined from slug-injection and swabbing-recovery tests can be an effective indicator of transmissive intervals in the open part of a borehole, especially if used in combination with a lithologic log. Relative specific capacity is the rate at which a straddle-packed interval accepts water during a slug-injection test or yields water during a swabbing-recovery test, divided by the difference between the static water level and a water level measured 3–4 min after the start of the test (Blankennagel et al., 1964; Blankennagel, 1967). Relative specific capacity is expressed in gallons per minute per foot of drawdown (gpm/ft). Relative specific capacity values typically are used to identify transmissive intervals, but in combination with an incomplete flow survey, they can be used to complete apportioning flow within the open part of a borehole. For example, a tracejector flow survey conducted in borehole UE-20f at Pahute Mesa accounted for 80% of flow from the borehole during a pumping test conducted August 9–11, 1964. The flow survey results are listed in Table 5.

30

A.L. Geldon 400 CALICO HILLS FORMATION

DEPTH BELOW LAND SURFACE, IN METERS

500

PROW PASS TUFF 600

BULLFROG TUFF 700

Figure 27. Flow surveys conducted in borehole UE-25 c#3, 1984–1995. (Data and geologic information from Geldon, 1993, 1996; Geldon et al., 2002.)

800

TRAM TUFF 900

OXYGEN ACTIVATION SPINNER TRACEJECTOR HEAT-PULSE FLOWMETER

1000 0

10

20

30

40 50 60 PERCENT FLOW

Relative specific capacity values obtained from nine sluginjection tests and one swabbing-recovery test between depths of 1358 and 2739 m in UE-20f mostly ranged from 0 to 0.05 gpm/ft, but the interval from 1392 to 1451 m, which is a rhyolite lava flow in the Rhyolite of Inlet, had a relative specific capacity value of 0.39 gpm/ft. Because the relative specific capacity of the lava flow in the Rhyolite of Inlet was so much larger than that of the other intervals tested, this lava flow appears to be the only transmissive interval indicated by the slug-injection and swabbing-recovery tests. The 20% of flow not detected by the tracejector survey in the open part of borehole UE-20f is interpreted to be coming from the rhyolite lava flow present between depths of 1392 and 1451 m. Used singly or together, geophysical logs effectively can identify transmissive intervals in wells. Figure 29 is a temperature log that was run in borehole UE-25 c#3 at Yucca Mountain. Inflections in the thermal gradient indicate inflow or outflow to the well, and acoustic televiewer, television, and resistivity logs establish upper and lower limits of the intervals transmitting water to or from the well (Geldon, 1996). Most points where water enters or leaves the well are associated with intervals of

70

80

90

100

moderately to very fractured rock and not lithologic variations, such as the degree to which ash-flow tuff layers are welded. Earth Tides and Barometric Effects Water-level altitudes in wells completed in the study area are affected by Earth tides and changes in atmospheric pressure associated with semidiurnal atmospheric heating and cooling and the movement of weather systems through the area (Galloway and Rojstaczer, 1988). The five principal solar and lunar tides have frequencies of 0.9–2.0 cycles per day. Although a lag is possible, atmospheric-pressure changes in the study area typically cause synchronous water-level changes in wells that are opposite in sense and less than the full magnitude of the atmospheric-pressure changes (Fig. 30). Earth tides and atmospheric-pressure change superimpose water-level changes on those caused by the withdrawal or injection of water during a hydraulic test. In the production well, these superimposed water-level changes generally are much smaller than water-level changes caused by the test and can be ignored. In the proportionately few tests in which observation wells were

Implications for groundwater flow in the Southwest Nevada Volcanic Field

Figure 28. Configuration of slug-injection tests in borehole UE-25 c#1 at Yucca Mountain (Geldon, 1996).

used, it was found that removing the effects of Earth tides and atmospheric-pressure change was advantageous but not always necessary. For example, analyses of drawdown in observation well UE-25 c#2 during pumping tests conducted in UE-25 c#3 in May 1984 and May 1995 produced the same values of

31

transmissivity, hydraulic conductivity, and storativity, although corrections for atmospheric-pressure change were made only in the second test (Geldon, 1996; Geldon et al., 1998). UE-25 c#2 is located ~29 m from UE-25 c#3. In observation wells that are hundreds to thousands of meters from a production well, Earth tides and atmospheric-pressure change inevitably obscure hydrologic responses to pumping and injection and must be removed to detect these responses. A study was done in 1993 to evaluate effects of Earth tides and atmospheric-pressure change on water-level altitudes in wells at Yucca Mountain (Geldon et al., 1997). Simultaneous records of water-level altitudes in the C-holes, boreholes UE-25 c#1, UE-25 c#2, and UE-25 c#3, and atmospheric pressure at and near the C-holes were obtained from July 15 to September 8, 1993. Each of the C-holes, was open from the water table, at or near the top of the Calico Hills Formation, to the Tram Tuff. Earth tides and semidiurnal atmospheric-pressure changes were removed from continuously monitored water-level altitudes and atmospheric pressures by applying a low-pass filter with a cutoff frequency of 0.8 cycles per day. As shown in Figure 31, long-term trends in the data were not disturbed by filtering. The barometric efficiency of boreholes UE-25 c#1, UE-25 c#2, and UE-25 c#3 was determined by fitting a straight line to a plot of changes in filtered water-level altitudes as a function of concurrent changes in filtered atmospheric pressures. The slope of this line (the barometric efficiency) averaged 0.94 for the C-holes in the 1993 study. As shown in Figure 32, applying a barometricefficiency correction of 0.94 to water-level changes recorded in borehole UE-25 c#1 during the passage of two storms over Yucca Mountain between August 24 and September 5, 1993, dampened these water-level changes to ~1 ft (0.3 m). Successful application of the methods used to remove the effects of Earth tides and atmospheric-pressure change on water levels in the 1993 study validated these methods for use in analyzing constant-rate pumping and injection tests that followed. Barometric efficiency was determined for 18 intervals in 7 wells before, during, or after cross-hole hydraulic tests conducted at Yucca Mountain from 1995 to 1998 using methods developed in the 1993 study (Geldon et al., 1998; 1999; 2002). The barometric efficiency of these intervals was found to range from 0.83 to 1.0 (Table 6). If the barometric efficiency of an interval from which water-level data were obtained during a constant-rate

TABLE 5. TRANSMISSIVE INTERVALS INDICATED BY A TRACEJECTOR FLOW SURVEYIN BOREHOLE UE-20F, PAHUTE MESA, AUGUST 1964 Depth to top of interval (m) 2214 2549 2974 3011 3708

Depth to bottom of interval (m)

Geologic unit

Lithology

Percent borehole flow

2326 2974 3011 3018 3739

Bullfrog Tuff Dead Horse Flat Formation Grouse Canyon Tuff Rhyolite of Handley Dacite of Mt. Helen?

Zeolitized, nonwelded to partly welded ash-flow tuff Comendite lava flows Silicified, nonwelded tuff Rhyolite flow breccia Rhyodacite lava flow

4 61 4 8 3

Note: Flow data from Thordarson and Rush, unpublished U.S. Geological Survey report; geology from Orkild and Jenkins, 1978; Warren et al., 1998.

32

A.L. Geldon 400 CALICO HILLS FORMATION

450

DEPTH BELOW LAND SURFACE, IN METERS

500

550 PROW PASS TUFF 600

Figure 29. Temperature log run in borehole UE-25 c#3 during a pumping test conducted in May 1984, showing the relation between zones of moderately to very fractured rock and intervals where water enters or leaves the well. (Compiled from data in Geldon, 1996.)

650 BULLFROG TUFF 700

750

800 TRAM TUFF 850

900 37

38

39

40

41

42

DIFFERENCE FROM MEAN, IN CENTIMETERS

TEMPERATURE, IN DEGREES CELSIUS

7 6

WATER PRESSURE

5

ATMOSPHERIC PRESSURE

4 3 2

Figure 30. Synchronous changes in atmospheric pressure and water pressure in the lower Bullfrog Tuff in borehole UE-25 c#2, June 23–29, 1995 (Geldon et al., 2002).

1 0 -1 -2 -3 -4 -5 0

1000

2000

3000

4000

5000

6000

ELAPSED TIME, IN MINUTES

7000

8000

9000

Implications for groundwater flow in the Southwest Nevada Volcanic Field

33

Figure 31. Result of filtering out Earth tides from water altitudes recorded June 15–22, 1993, in borehole UE-25 c#1 at Yucca Mountain (Geldon et al., 1997).

Figure 32. Result of applying a correction for atmospheric-pressure change to water-level altitudes recorded August 24 to September 5, 1993, in borehole UE-25 c#1 at Yucca Mountain (Geldon et al., 1997).

hydraulic test was needed but unknown, it was estimated from this range of known values. Analytical Methods

realistic (Geldon, 1996). Alternative analytical methods used to obtain hydraulic properties without modification from published reports, while considered most appropriate by the authors of those reports, are not discussed herein.

Analytical methods used in this study are discussed briefly. These methods are considered the simplest appropriate for hydrogeologic settings in the study area. Early attempts to analyze hydraulic tests conducted in the C-holes at Yucca Mountain demonstrated that alternative analytical methods to those discussed were neither more accurate nor conceptually more

Constant-Rate Pumping, Injection, and Airlift Tests Constant-rate pumping, injection, and airlift tests were analyzed by conventional methods developed for porous media (Walton, 1970; Lohman, 1979; Driscoll, 1986; Dawson and Istok, 1991). These hydraulic tests were analyzed by curve-fitting methods and by straight-line fitting methods. Curve-fitting methods

34

A.L. Geldon

involve matching drawdown or recovery data plotted as a function of elapsed time on log-log scales to dimensionless type curves, and then substituting the match-point values into analytical equations to determine hydraulic properties. Straight-line fitting methods involve regression of drawdown or residual drawdown data as a function of the log of elapsed time or distance from the test well, and then substituting the slope of the line fit to the data into analytical equations to determine hydraulic properties. Under the assumption of an infinite, homogeneous, isotropic, confined aquifer, drawdown or recovery data from an observation well can be matched to the exponential integral curve of Theis (1935) to determine transmissivity, hydraulic conductivity, and storativity. Data from the production well can be used to determine transmissivity and hydraulic conductivity. Equations 1–3 are used to calculate hydraulic properties. Under the same assumptions applicable for the solution of Theis (1935), the slope of a straight line fit to drawdown or recovery data plotted as a function of log time can be used to determine transmissivity, hydraulic conductivity, and storativity using Equation 2 and the following equations (Cooper and Jacob 1946): T= S=

2.3 × Q 4 π∆sd

(5)

2.25Tt0 r2

(6)

where ∆sd is the drawdown over 1 log cycle of time; t0 is the time at which the drawdown is 0; and all other variables are the same as in Equations 1–3.

Residual drawdown in the production well can be analyzed to determine transmissivity and hydraulic conductivity by plotting residual drawdown as a function of the log of the ratio of time since withdrawal or injection started to time since withdrawal or injection stopped. This analytical solution is called the Theis (1935) recovery method. Equations 2 and 5 are used to solve for hydraulic properties, except that ∆sd in Equation 5 in this method is the residual drawdown. Under the assumption of a leaky, confined aquifer without storage in the confining layer, Cooper (1963) developed analytical solutions to determine transmissivity, hydraulic conductivity, and storativity from drawdown or recovery data plotted on log-log scales as a function of either elapsed time or the ratio of elapsed time to the square of the distance from the production well. The relevant equations are Equation 2 and: T=

Q × L(u, v) 4πs

(7)

4T t r 2 lu

(8)

S=

v = r 2 × K ′ (Tb ′)

(9)

where L(u, ν) is the well function of a leaky, confined aquifer without storage in the confining layer; u is a dimensionless parameter defined by Equation 8; ν is a dimensionless parameter defined by Equation 9; t/r2 is the ratio of elapsed time to the square of distance from the test well (L/T2) corresponding to 1/u;

TABLE 6. BAROMETRIC EFFICIENCY VALUES DETERMINED FROM CONCURRENT MEASUREMENTS OF ATMOSPHERIC PRESSURE AND STATIC WATER-LEVEL ALTITUDES IN WELLS AT YUCCA MOUNTAIN Borehole UE-25 c#1 UE-25 c#1 UE-25 c#1 UE-25 c#1 UE-25 c#2 UE-25 c#2 UE-25 c#2 UE-25 c#2 UE-25 c#3 UE-25 c#3 UE-25 c#3 UE-25 c#3 UE-25 c#3 UE-25 ONC#1 UE-25 ONC#1 USW H-4 UE-25 WT#3 UE-25 WT#14

Interval

Barometer location

Period of record

Barometric efficiency

Regression coefficient

Calico Hills Formation to Tram Tuff Prow Pass Tuff Upper Bullfrog Tuff Lower Bullfrog Tuff Calico Hills Formation Prow Pass Tuff Upper Bullfrog Tuff Lower Bullfrog Tuff Calico Hills Formation to Tram Tuff Calico Hills Formation Calico Hills Formation Prow Pass Tuff Lower Bullfrog Tuff Prow Pass Tuff Prow Pass Tuff Prow Pass Tuff to Lithic Ridge Tuff Bullfrog Tuff Topopah Spring Tuff and Calico Hills Formation

WX-3 C-holes C-holes C-holes C-holes C-holes C-holes C-holes WX-3 C-holes C-holes C-holes C-holes UE-25 ONC#1 UE-25 ONC#1 UE-25 ONC#1 C-holes C-holes

July 15-Sept 8, 1993 June 23–29, 1995 June 24–29, 1995 June 23–29, 1995 June 23–29, 1995 June 23–29, 1995 June 23–29, 1995 June 23–29, 1995 July 15–Aug 17, 1993 February 7–8, 1996 Apr 20–May 1, 1998 Apr 20–May 1, 1998 May 9–13, 1996 July 1–Sept 13, 1995 Apr 20–May 1, 1998 June 8–12, 1995 June 4–12, 1995 June 4–12, 1995

0.95 0.96 0.99 0.97 0.93 0.93 0.93 0.91 0.93 0.83 0.94 1.0 0.87 0.99 0.99 0.91 0.91 0.89

0.86 0.98 0.97 0.98 0.94 0.97 0.97 0.96 0.86 0.89 No Data No Data 0.92 0.90 No Data 0.87 0.82 0.94

Note: Data from Geldon et al., 1997; 1998; 1999; 2002.

Implications for groundwater flow in the Southwest Nevada Volcanic Field s is drawdown or recovery (L) corresponding to L(u, ν); K′ is vertical hydraulic conductivity of the confining layer (L/T); b′ is the thickness of the confining layer (L); and all other variables are the same as in previous equations. Under the assumption of a leaky, confined aquifer with storage in the confining layer, Hantush (1961) developed analytical solutions to determine transmissivity, hydraulic conductivity, and storativity from drawdown or recovery data plotted on log-log scales as a function of elapsed time. Relevant equations are Equation 2, 3, and: T = Q × H(u, β) 4πs β = r ( 4b) ×

[ (K ′S′) (KS ) ] s

s

Q × W (uA , uB ,β) 4 πs Kr = T/b

(17)

(10)

Kf = T/b

(18)

(11)

Kb =

TH B2

(19)

4T t Sf = r2θ

(20)

Sb = Sf × (η – 1)

(21)

(12)

(13)

b2 r2

(14)

S=

4TtA uA r2

(15)

Sy =

4TtBuB r2

(16)

KZ Kr =

Under the assumption of dual fracture and matrix permeability in a confined aquifer, Streltsova-Adams (1978) developed an analytical solution to determine transmissivity, fracture and matrix hydraulic conductivity, and fracture and matrix storativity from drawdown or recovery data plotted on log-log scales as a function of elapsed time. Relevant equations are: Q × W (θ, r B) 4 πs

where H(u, β) is the well function of a leaky, confined aquifer with storage in the confining layer; s is drawdown or recovery (L) corresponding to H(u, β); β is a dimensionless parameter defined by Equation 11; Ss′ is the specific storage of the confining layer (L–1); Ss is the specific storage of the aquifer (L–1); and all other variables are the same as in previous equations. Under the assumption of an infinite, homogeneous, anisotropic, unconfined aquifer, Boulton (1963), Stallman (1965), and Neuman (1975) developed analytical solutions to determine transmissivity, hydraulic conductivity, anisotropy, and storativity from drawdown or recovery data plotted on log-log scales as a function of elapsed time. For the solution of Neuman (1975), the relevant equations are: T=

35

where W(uA, uB, β) is the well function of an anisotropic, unconfined aquifer; uA is a dimensionless parameter defined by Equation 15; uB is a dimensionless parameter defined by Equation 16; β is a dimensionless parameter defined by Equation 14; tA is the elapsed time (T) corresponding to uA; tB is the elapsed time (T) corresponding to uB; s is drawdown or recovery (L) corresponding to W(uA, uB, β); Kr is horizontal hydraulic conductivity (L/T); Kz is vertical hydraulic conductivity (L/T); Kz/Kr is the vertical to horizontal anisotropy; Sy is the specific yield (dimensionless); and all other variables are the same as in previous equations.

T=

where W(θ, r/B) is the well function of a confined aquifer with fracture and matrix permeability; B is a dimensionless parameter defined by Equation 19; θ is a dimensionless parameter defined by Equation 20; η is a dimensionless parameter defined by Equation 21, assumed to equal 10 in this study; H is the distance from the center of a block to a bounding fracture (L), which is equivalent to half the average distance between fractures; t is the elapsed time (T) corresponding to θ; s is drawdown or recovery (L) corresponding to W(θ, r/B); Kf is fracture hydraulic conductivity (L/T); Kb is matrix hydraulic conductivity (L/T); Sf is fracture storativity (dimensionless); Sb is matrix storativity (dimensionless); and all other variables are the same as in previous equations. Slug-Injection and Swabbing Recovery Tests In slug-injection tests, water is injected into a well instantaneously. In single-run swabbing-recovery tests, water is displaced from a well instantaneously by lowering a mechanical device into the well. In both types of tests, the recovery to the static water level is analyzed. Cooper et al. (1967) developed a method for analyzing these tests, which was modified later by Bredehoeft and Papadopulos (1980). In the solution of Cooper et al. (1967), ratios of the water level as the test progresses to the static water level (H/H0) are plotted as a function of log time since the test started, and the data curve is then matched to a dimensionless type curve to obtain hydraulic properties. Transmissivity is obtained from the equation: T = β × rc2/t

(22)

where T is transmissivity (L2/T); β is a dimensionless parameter defined by Equation 22, which generally is picked to equal 1 in order to simplify the calculation; rc is the radius of the casing

36

A.L. Geldon

in which the water-level fluctuates (L); and t is the time since the test started. Hydraulic conductivity usually is determined by dividing the length of the open interval into the transmissivity value, although it generally is known in advance that the entire test interval is not equally transmissive. Theoretically, storativity can be calculated by this method, but these calculations are imprecise and are not recommended (Barker and Black, 1983; Cooper et al., 1967). In some swabbing-recovery tests, a mechanical device is lowered into the well to displace water repeatedly. After the swabbing is finished, the average withdrawal rate is calculated as the total volume of water removed divided by the time required to remove the water. This calculation does not account for drainage back to the well between swabbing runs. Residual drawdown is then analyzed using the Theis (1935) recovery method. Analytical Uncertainty An omnipresent feature of hydraulic tests at Yucca Mountain, Pahute Mesa, and in adjacent areas is the tendency for most of the drawdown and recovery to occur very rapidly, especially in a pumping well (Winograd and Thordarson, 1975; Geldon, 1993). In many pumped wells, 80%–90% of the drawdown and recovery occurs within 10 min of starting or stopping the pump. These rapid water-level changes generally are attributable to draining of water stored in the well (commonly termed “borehole storage”) and well losses—head lost from (1) water turbulently entering the well from the aquifer; (2) inefficient placement of the pump, openings, and other well-design features; and (3) drilling-caused damage to the aquifer near the well. Estimates of transmissivity from specific capacity typically are way too large, because the equation used to estimate transmissivity from specific capacity (Lohman, 1979) assumes that drawdown is spread out over the length of the test instead of being concentrated within the initial part of the test. In tests with rapid recovery, the Theis (1935) recovery method also fails, because the analysis tends to be weighted toward very small water-level changes toward the end of the recovery period. These small changes have a very flat slope, which is inversely proportional to transmissivity. Thus, the Theis (1935) recovery method tends to overestimate transmissivity. Another straight-line fitting method that must be used with caution in the study area is that of Cooper and Jacob (1946). This analytical method assumes a homogeneous, isotropic, confined aquifer. In such an aquifer, drawdown or recovery data plotted as a function of the log of elapsed time conform to a straight line. The slope of this line can be used to calculate transmissivity. Typically, two to three straight-line segments, in addition to a steeply sloping segment caused by well losses, are obtained in constant-rate pumping and injection tests in the volcanic rocks at Yucca Mountain and Pahute Mesa (Fig. 33). If three segments are present, and the first and third segments have about twice the slope as the second segment, the response is characteristic of either an anisotropic, unconfined aquifer or a confined aquifer

with dual fracture and matrix permeability. A straight line fit to the third segment will produce a reasonable value of transmissivity using the method of Cooper and Jacob (1946). If two segments are present, in addition to a steeply sloping segment caused by well losses, the response could be interpreted as either an incomplete dual-permeability-aquifer response caused by premature termination of the test or a leaky, confined-aquifer response. With a two-segmented response, analysis of the first segment would produce the most reasonable value of transmissivity. Because the correct analytical model cannot be known in advance of a hydraulic test, selecting the segment for analysis by the method of Cooper and Jacob (1946) often is arbitrary. Use of this method to analyze multi-segmented hydrologic responses typically results in overestimates of transmissivity. Type-curve matching has its own problems. The method chosen must be appropriate for the hydrogeologic setting. Given the time-dependent nature of the hydrologic response (Fig. 24), different analytical methods might seem appropriate as a hydraulic test progresses. Furthermore, the data often are inadequate for a unique match within a family of type curves. Values of transmissivity and storativity in the database are believed to be accurate to at least one significant figure, but values of hydraulic conductivity are more uncertain. Hydraulic conductivity can be calculated from the known thickness of transmissive intervals within a test interval, the entire thickness of the test interval, or any assumed thickness of transmissive rock. Borehole flow surveys do not always agree with other indicators of flow, such as relative specific capacity values computed from slug-injection tests or temperature gradient inflections. Because of uncertainty regarding transmissive thickness, determining hydraulic conductivity can be subjective, even when transmissivity has been determined confidently. Effects of Test Scale on Determination of Hydraulic Properties Values of intrinsic permeability, hydraulic conductivity, and transmissivity are dependent on the scale of the tests conducted to obtain these properties (Dagan 1986; Neuman, 1990). This phenomenon generally is attributed to increasing access to conduits for fluid flow as the volume of the medium encompassed by the test increases. Permeameter tests of core samples done in the laboratory indicate rock matrix properties. Single-well hydraulic tests, such as slug-injection and swabbing-recovery tests, optimally determine hydraulic properties in the near-borehole environment. Cross-hole hydraulic tests incorporate the influence of field-scale features, such as faults, facies changes, and stratigraphic pinch-outs. Figure 34, a plot of hydraulic conductivity values determined for Miocene volcanic rocks in the study area as a function of the radial distance in permeameter tests, singlewell hydraulic tests, and cross-hole hydraulic tests, shows that hydraulic conductivity values determined at different test scales generally are incompatible. As shown in Figure 35, data obtained from pumping tests conducted at two sites at Yucca Mountain, Bow Ridge and Drill-

Implications for groundwater flow in the Southwest Nevada Volcanic Field

37

0

DRAWDOWN, IN METERS

Pumping test in UE-19gs, Pahute Mesa: Bullfrog, Tram, and Grouse Canyon Tuffs, and Dead Horse Flat Formation, March 26–27, 1965

A

2

4 WELL LOSS 6

8

WATER FROM AQUIFER

10 WATER RECHARGED FROM ABOVE OR BELOW A CONFINED AQUIFER

12

14 0.1

1

10

100

1000

10000

TIME SINCE PUMPING STARTED, IN MINUTES

0.0 Pumping test in USW VH-1, Crater Flat: Topopah Spring, Prow Pass, and Bullfrog Tuffs, February 10-11, 1981

B

0.2

DRAWDOWN, IN METERS

0.4 0.6 WATER FROM FRACTURES

0.8

Figure 33. Typical multi-segmented pumping responses of Tertiary volcanic rocks in the Yucca Mountain and Pahute Mesa areas. (A) Well loss and two-segmented response of a leaky confined aquifer. (B) Three-segmented response of a confined aquifer with dual fracture and matrix permeability. (C) Threesegmented response of an unconfined, anisotropic aquifer. (Data from Thordarson and Howells, 1987; Blankennagel and Weir, 1965; Winograd, 1965.)

TRANSITIONAL FLOW OF WATER FROM MATRIX TO FRACTURES

1.0 1.2 1.4 1.6

WATER FROM MATRIX STORAGE AND FRACTURE DRAINAGE

1.8 2.0 2.2 0.1

1

10

100

1000

10000

TIME SINCE PUMPING STARTED, IN MINUTES

7

C

DRAWDOWN, IN METERS

8

ELASTIC RELEASE OF WATER FROM AQUIFER STORAGE

Pumping test in J-13, Jackass Flats, Topopah Spring, Tram, and Lithic Ridge Tuffs, February 18–22, 1964

9

10 TRANSITIONAL DRAINAGE OF WATER FROM AQUIFER STORAGE TO UNCONFINED PORES

11

12 DRAINAGE OF WATER FROM UNCONFINED PORES

13

14 1

10

100

1000

TIME SINCE PUMPING STARTED, IN MINUTES

10000

38

A.L. Geldon

HYDRAULIC CONDUCTIVITY, IN METERS PER DAY

hole Wash, demonstrate that much larger drawdown occurs in the pumping well than in nearby observation wells in the same test. Because drawdown is inversely proportional to transmissivity, analysis of the pumping well data indicates much smaller values of transmissivity and hydraulic conductivity than analyses of observation well data in the same test. Analyses of pumping-well data are unreliable indicators of aquifer properties. Unfortunately, hydraulic tests at most sites in the study area were conducted without observation wells. Appendix B lists 20 sites where hydraulic-property data were obtained from analyses of drawdown or recovery in the pumping well, but only five sites where hydraulic-property data were obtained from analyses of observation well data. Plotted distributions of hydraulic properties in the Younger Tertiary tuff and lava flows HSU developed using data from single-well and cross-hole hydraulic tests, together, would be misleading. The expectation that knowledge of this situation is going to produce more cross-hole tests is unrealistic. Single-well hydraulic tests require much less time and money to carry out than cross-hole hydraulic tests, and neither federal nor state agencies are committed to widespread cross-hole hydraulic testing in the study area in the immediate future. One can throw out all of the single-well test data and rely only on the limited cross-hole test data for modeling groundwater flow and contaminant transport. Unfortunately, that would be very simplistic, because the Younger Tertiary tuff and lava flows HSU is very heterogeneous. One has to find a way to convert data from the single-well hydraulic tests to cross-hole scale to account for this heterogeneity. An empirical approach using (1) paired analyses of production well and observation well data for the same test and (2) analyses of data obtained from tests conducted at different scales in the same well interval

appears to be the only way to scale up the single-well hydraulic test data. Statisticians might object to this approach because of an insufficient number of data pairs, but if more cross-hole test data existed, there would be no need to find a way to make the single-well test data usable. A scaling equation was developed from (1) seven paired analyses of pumping well and observation well data from six pumping tests in four wells, and (2) three paired analyses of data obtained from tests conducted at different scales in three intervals of borehole UE-25 c#1 (Table 7). Hydraulic conductivity values obtained at a cross-hole scale were plotted as a function of hydraulic conductivity values at a single-well test scale (Fig. 36): With a correlation coefficient of 0.74, the following relation was determined: Kch = 23.541 × Ksw0.575

(23)

where Kch is cross-hole-scale hydraulic conductivity (L/T); and Ksw is single-well-test-scale hydraulic conductivity (L/T). Equation 23 can be used for the Younger Tertiary tuff and lava flows HSU anywhere in the Southwest Nevada Volcanic Field to estimate hydraulic conductivity which might be present hundreds of meters from a well in which a pumping or injection test has been conducted. This equation was used to estimate distributions of hydraulic conductivity which are discussed later in this report. HYDRAULIC PROPERTIES The determination of hydraulic properties from cross-hole, constant-rate, pumping and airlift tests conducted at Yucca Mountain, Pahute Mesa, and Frenchman Flat is discussed below. The Yucca Mountain hydrologic domain is represented by tests

100 10 1 0.1 0.01 0.001 0.0001

CROSS-HOLE HYDRAULIC TESTS SINGLE-WELL PUMPING TESTS

0.00001

SLUG-INJECTION AND SWABBING TESTS 0.000001

PERMEAMETER TESTS

0.0000001 0.01

0.1

1

10

100

RADIAL DISTANCE, IN METERS

1000

10000

Figure 34. Relation of the hydraulic conductivity of Miocene volcanic rocks to the scale of hydraulic tests conducted at Yucca Mountain and Pahute Mesa and in adjacent areas. (Field test data from Appendix B; Permeameter test data from Anderson 1981, 1991, 1994; Thordarson 1983; Lahoud et al., 1984; Rush et al., 1984; Geldon 1993, 1996.)

Implications for groundwater flow in the Southwest Nevada Volcanic Field at two sites—Bow Ridge (the C-holes complex) and Drill Hole Wash. The Pahute Mesa hydrologic domain is represented, also, by tests at two sites – the Bullion nuclear test site (the ER-20-6 well cluster) and the Knickerbocker nuclear test site. Because discussion of all hydraulic tests in the study area that were used to prepare this report would be impractical, Appendix B presents summary hydraulic-property data from all of these tests. The C-holes Complex The C-holes complex was constructed from 1983 to 1984 on the east flank of Yucca Mountain to determine hydraulic

100

39

properties of volcanic rocks in the saturated zone near the potential nuclear waste repository site (Geldon, 1993). The C-holes complex, at an altitude of 1130–1132 m AMSL, consists of three orthogonally oriented boreholes, UE-25 c#1, UE-25 c#2, and UE-25 c#3, that are located where an ephemeral stream cuts through the northern end of Bow Ridge (Fig. 20). The C-holes are 30.4–76.6 m apart at the land surface (Fig. 37), but because of borehole deviation during drilling, the boreholes are ~29–79 m apart at the water table and ~30–87 m apart at total depth. Each of the boreholes was drilled to a depth of 914.4 m, but they have collapsed several to tens of meters since they were drilled. The boreholes are telescoped downward (Fig. 38). Tack-cemented

A

DRAWDOWN, IN METERS

10

1

0.1

UE-25 a#1 (Observation well)

0.01

UE-25 b#1 (Pumping well)

0.001 0.0001

0.001

0.01

0.1

1

10

100

1000

10000

100000

1000000

TIME SINCE PUMPING STARTED/DISTANCE FROM PUMPING WELL, IN MINUTES/METER SQUARED

100

B

DRAWDOWN, IN METERS

10

1

0.1

UE-25 c#2 (Observation well) UE-25 c#3 (Pumping well) 0.01 0.001

0.01

0.1

1

10

100

1000

10000

100000

1000000

TIME SINCE PUMPING STARTED/DISTANCE FROM PUMPING WELL, IN MINUTES/METER SQUARED

Figure 35. Drawdown in observation and pumping wells. (A) Pumping test in UE-25 b#1, Calico Hills Formation to Bullfrog Tuff, Drillhole Wash, August 29–September 1, 1981. (B) Pumping test in UE-25 c#3, Calico Hills Formation to Tram Tuff, Bow Ridge, May 22–June 1, 1995. (Data from Moench, 1984; Geldon et al., 1998.)

40

A.L. Geldon

TABLE 7. PAIRED HYDRAULIC CONDUCTIVITY VALUES DETERMINED AT SINGLE-WELL AND CROSS-HOLE HYDRAULIC TEST SCALES FROM PUMPING AND INJECTION TESTS CONDUCTED AT YUCCA MOUNTAIN AND FRENCHMAN FLAT Pumping or injection well

Date

Test type

K (m/d)

Analytical method

Observation well

Date

Test type

K Analytical method (m/d)

Geologic units

Water well 4

02/22/90

Pumping

0.79

Neuman (1975)

Water well 4a

02/22/90

Pumping

20

UE-25 b#1

08/29/81

Pumping

0.87

Neuman (1975)

UE-25 a#1

08/29/81

Pumping

7.8

Neuman (1975)

Calico Hills Formation to Bullfrog Tuff

UE-25 c#3

05/04/84

Pumping

0.10

Cooper (1963)

UE-25 c#2

05/04/84

Pumping

13

Neuman (1975)

Calico Hills Formation to Tram Tuff

UE-25 c#3

05/22/95

Pumping

0.11

Cooper (1963)

UE-25 c#1

05/22/95

Pumping

7.3

Neuman (1975)

Calico Hills Formation to Tram Tuff

UE-25 c#3

05/08/96

Pumping

0.67

Cooper (1963)

UE-25 c#2

05/08/96

Pumping

20

Streltsova-Adams (1978)

Lower Bullfrog Tuff

UE-25 c#3

05/08/96

Pumping

0.67

Cooper (1963)

UE-25 c#1

05/08/96

Pumping

40

Streltsova-Adams (1978)

Lower Bullfrog Tuff

UE-25 c#2

06/02/98

Pumping

0.029

Cooper and Jacob (1946)

UE-25 c#1

06/02/98

Pumping

3.4

Cooper (1963)

Prow Pass Tuff

UE-25 c#1

10/09/83

Sluginjection

0.009

Cooper and others (1967)

UE-25 c#1

05/04/84

Pumping

0.82

Neuman (1975)

Calico Hills Formation

UE-25 c#1

Oct. 6–9, 1983

Sluginjection

0.011

Cooper and others (1967)

UE-25 c#1

06/12/95

Pumping

3.2

Theis (1935)

Prow Pass Tuff

UE-25 c#1

Oct. 7–11, 1983

Sluginjection

0.042

Cooper and others (1967)

UE-25 c#1

06/12/95

Pumping

2.0

Theis (1935)

Upper Bullfrog Tuff

Streltsova-Adams Rainier Mesa and (1978) Topopah Spring Tuffs

HYDRAULIC CONDUCTIVITY FROM CROSS-HOLE TESTS, IN METERS/DAY

Note: Data from Lahoud et al., 1984; Moench 1984; Geldon et al., 1998, 1999, 2002; Geldon 1993, 1996; U.S. Geological Survey files; K (m/d), hydraulic conductivity in meters per day.

100

10

Figure 36. Relation between paired hydraulic conductivity values determined at single-well and cross-hole hydraulic test scales from pumping and observation well data in the same tests and from different scale tests in the same well interval, Yucca Mountain and Frenchman Flat. (Data from Table 7.)

1

0.1 0.001

0.01

0.1

1

HYDRAULIC CONDUCTIVITY FROM SINGLE-WELL TESTS, IN METERS/DAY

10

Implications for groundwater flow in the Southwest Nevada Volcanic Field casing extends <20 m below the water table, which is 400–402 m below the land surface at the site. Individual boreholes are sealed from surface contamination by cement emplaced around casing to depths of 96–112 m. The C-holes are completed in Miocene volcanic rocks (Fig. 39), which consist of nonwelded to densely welded ashflow tuff with tuff breccia and bedded ash-fall tuff, reworked tuff, sandstone, and siltstone (Geldon, 1993). The volcanic

Figure 37. Surface locations of boreholes UE-25 c#1, UE-25 c#2, and UE-25 c#3 (the C-holes complex) at Yucca Mountain; boreholes are referenced to Nevada State, Zone 2, coordinates (Geldon 1993).

41

rocks, which are pervaded by tectonic and cooling fractures (Fig. 13), are ~1040–1590 m thick in the vicinity of the C-holes (Geldon et al., 1998). They are covered by a thin veneer of Quaternary alluvium and underlain unconformably by Paleozoic limestone and dolomite (Fig. 7). North-northeasterly trending, westerly dipping faults, including the Paintbrush Canyon, Midway Valley, Bow Ridge, and Dune Wash Faults (Fig. 39), displaced the volcanic rocks at Yucca Mountain down to the west and tilted these rocks to the east at angles of 5° to 20° (Frizzell and Shulters, 1990). Subsequent to this extensional faulting, the northwesterly trending Antler Wash Fault zone cut across and offset north-northeasterly trending faults at Bow Ridge (Geldon et al., 2002). Six discrete intervals in the Calico Hills Formation and the Prow Pass, Bullfrog, and Tram Tuffs transmit water to the C-holes (Fig. 40). These transmissive intervals have fracture and matrix permeability that are not correlated with either fracture orientation, fracture intensity, or the degree of welding. The principal influence on permeability appears to be the faults that intersect the C-holes, because 90% of the water produced from these wells comes from intervals in close proximity to cross-cutting faults. Nine constant-rate, cross-hole pumping and injection tests were conducted at the C-holes complex from March 1984 to September 1998 (Geldon, 1996; Geldon et al., 1998, 2002). These hydraulic tests were designed to determine: (1) hydraulic properties of the full saturated zone thickness of the Younger Tertiary tuff and lava flows HSU at the C-holes complex; (2) hydraulic properties of the six discrete transmissive intervals within this HSU at the C-holes complex; (3) possible heterogeneity related to fault and fracture orientations within the structural block containing the C-holes; (4) the extent to which diverse geologic units that transmit water in the vicinity of the C-holes are connected hydraulically; (5) the locations of recharge boundaries within, and barrier boundaries adjacent to the Yucca Mountain hydrologic domain; and (6) possible hydraulic connection between Tertiary volcanic rocks and underlying Paleozoic carbonate rocks in the Yucca Mountain hydrologic domain. Borehole flow surveys (Fig. 27), borehole temperature logs (Fig. 29), borehole resistivity, acoustic televiewer and television logs (Geldon, 1996), cross-hole seismic tomography, slug-injection tests (Fig. 12), step-drawdown tests, brief performance tests, and hydrochemical sampling were done before, during, and after the cross-hole tests to assist in the design, analysis, and interpretation of these tests. To conduct the cross-hole hydraulic tests, dual-mandrel packers were attached to drill tubing and lowered to selected depths in observation and production wells, where they were inflated to isolate test intervals. In the six tests conducted from 1995 to 1998, packers were placed in thick, unfractured, smoothwalled intervals above and below the well-delineated tops and bottoms of transmissive intervals to minimize potential leakage between packed-off intervals. Sections of well screen and slotted casing were emplaced in the drill-tubing string for hydraulic communication with test intervals. Continuous records of pressure and temperature in packed-off intervals during hydraulic

42

A.L. Geldon

Figure 38. Completion of boreholes UE-25 c#1, UE-25 c#2, and UE-25 c#3 (Geldon, 1993).

tests were obtained using differential or absolute pressure transducers suspended inside plastic tubing or attached to the drill tubing. Data acquired during hydraulic tests conducted in 1984 were recorded by electronic data loggers. During tests conducted from 1995 to 1998, data from the C-holes were monitored in real time and stored onsite on a personal computer, whereas data from other wells monitored in these tests were stored in electronic data loggers. Table 8 lists instrumentation used in the C-holes during the 1984–1998 hydraulic tests (for descriptions of instrumentation in monitoring wells other than the C-holes, see Nye County Nuclear Waste Repository Project Office, 1995; Graves, 2000). Continuous records of atmospheric pressure during all of the hydraulic tests except the one conducted in May 1984 were obtained by barometers placed inside a temperature-controlled trailer at the C-holes complex and at borehole UE-25 ONC#1. All calculations of drawdown in continuously and periodically monitored observation wells, pumping wells, and injection wells in all hydraulic tests in the C-holes, except the May 1984 test, incorporated corrections for atmospheric-pressure change. Calculations of drawdown in continuously monitored observation wells in which drawdown was anticipated to be smaller than the magnitude of Earth tides (wells more distant than UE-25 ONC#1) incorporated

corrections for Earth tides. Corrections of drawdown for atmospheric-pressure change and Earth tides were made as described in the section titled “Earth Tides and Barometric Effects.” Water pressures obtained by transducers, after correction for barometric effects and Earth tides, were converted to the length of the water column using an equation derived from the variation in water density with temperature at 1 atmosphere (Streeter and Wylie, 1975). This equation is: Pft = (2.3064 + 0.000031866 × T + 0.0000098745 × T 2) × Ppsi (24) where: Pft is pressure, in feet of water (ft); Ppsi is pressure, in pounds per square inch (psi); and T is water temperature, in degrees Celsius. Water temperatures in the C-holes during pumping tests generally ranged from 35 to 42 °C. Rounded to two decimal places, a conversion factor of 2.32 ft/psi was obtained at all temperatures. Multiplied by 0.3048 m/ft, this conversion factor equals 0.707 m/psi. During pumping tests conducted in the C-holes in February 1996 and from May 1996 to November 1997, all hydrogeologic intervals in the C-holes that were being moni-

Implications for groundwater flow in the Southwest Nevada Volcanic Field

Figure 39. Geologic map of Yucca Mountain, showing exploratory tunnels and boreholes (Modified from Day et al., 1998).

43

44

A.L. Geldon

tored responded to pumping, regardless of the interval being pumped. It is unlikely that all packers failed to seal properly, because the packers were seated in non-rugose, sparsely fractured zones. A more reasonable interpretation is that pumping caused vertical flow between transmissive intervals through fractures beyond borehole walls. Pumping test analyses had to account for this extraneous flow. Spinner and oxygen-activation flow surveys (Fig. 27) were run in UE-25 c#3 during the hydraulic test in June 1995 to determine the flow distribution in the C-holes under pumping conditions. However, these flow surveys failed to detect flow from the Prow Pass interval that was indicated by heat-pulse flowmeter surveys conducted without pumping in the C-holes in 1991 (Geldon, 1996). Results of the 1991 and 1995 flow surveys were combined algebraically to estimate flow distributions in UE-25 c#1 and UE-25 c#2 during the hydraulic test in June 1995, which are listed in Table 9. These flow distributions were adjusted for the hydraulic tests conducted in February 1996 and May 1996 to November 1997 (Table 8) by inserting discharge and drawdown values recorded at the same elapsed time in the three hydraulic tests into the following equation: P2 =

Q1 × P1 × s2 Q2 × s1

(25)

where P1 is the proportion of flow determined for a hydrogeologic interval during the hydraulic test in June 1995; P2 is the proportion of flow determined for a hydrogeologic interval during a hydraulic test in either February 1996 or May 1996 to November 1997; Q1 is the average discharge during the hydraulic test in June 1995; Q2 is the average discharge during a hydraulic test in February 1996 or May 1996 to November 1997; s1 is the drawdown in a hydrogeologic interval during the hydraulic test in June 1995; and s2 is the drawdown in a hydrogeologic interval during a hydraulic test in either February 1996 or May 1996 to November 1997. In the three hydraulic tests listed in Table 9, the Lower Bullfrog interval consistently contributed ~70% of the flow from observation wells to UE-25 c#3, the pumping well at the C-hole complex; the Upper Tram interval consistently contributed ~20% of this flow; and all other intervals combined contributed ~10% of the total flow. To analyze drawdown in any hydrogeologic interval in these three tests, the total discharge from UE-25 c#3 was first multiplied by the percentage of flow contributed by the interval being analyzed, in order to avoid calculating erroneously large values of transmissivity and storativity (both of which are directly proportional to discharge). Pumping Test in UE-25 c#3, May 22 to June 1, 1995 A pumping test was conducted in borehole UE-25 c#3 from May 22 to June 1, 1995, after which recovery was monitored until June 12, 1995 (Geldon et al., 1998; Table 8). Boreholes UE-25 c#1, UE-25 c#2, UE-25 ONC#1, USW H-4, UE-25 WT#3, and UE-25 WT#14 were used as observation wells (locations shown in Figures 14, 20, and 39). Observation wells that responded to pumping were located 29.0–2245 m from the pumping well, UE-25 c#3

Figure 40. Transmissive intervals in the C-holes (Geldon et al., 1998).

765.0–768.1, 792.5–795.5

UE-25 c#1

No packers

486.2–489.2, 512.1–515.1

UE-25 c#2

UE-25 c#1

717.8–720.5, 754.4–757.1

766.3–769.3, 790.7–793.4

UE-25 c#2

UE-25 c#1

No packers

No packers

No packers

UE-25 c#3

UE-25 c#2

UE-25 c#1

May 22–June 12, 1995

No packers

UE-25 c#3

October 30–December 7, 1984

No packers

UE-25 c#3

May 4–June 12, 1984

No packers

Packer depths (m)

UE-25 c#2

March 7–18, 1984

Borehole

Not applicable

Not applicable

Submersible pump attached to 14-cmdiameter drill tubing, with an intake depth at 450.2 m

Not applicable

Not applicable

Submersible pump attached to 14-cmdiameter drill tubing, with an intake depth at 443.2 m

Not applicable

Not applicable

Submersible pump attached to 14-cmdiameter drill tubing, with an intake depth at 443.2 m

Not applicable

Submersible pump attached to 14-cmdiameter drill tubing, with an intake depth at 441.0 m

Pump

Not applicable

Not applicable

Flowmeter inside a 15cm-diameter discharge line

Not applicable

Not applicable

Flowmeter inside a 15cm-diameter discharge line

Not applicable

Not applicable

Flowmeter inside a 15cm-diameter discharge line

Not applicable

Flowmeter inside a 15cm-diameter discharge line

Flow measurement

Temperature-compensated, absolute pressure transducer suspended on 7.3-cm-diameter drill tubing at a depth of 552.0 m

Temperature-compensated, absolute pressure transducer suspended on 7.3-cm-diameter drill tubing at a depth of 610.4 m

Temperature-compensated, absolute pressure transducer suspended on 14-cm-diameter drill tubing at a depth of 441.1 m

Three temperature-compensated, differential pressure transducers suspended on 7.4 cm, outside-diameter plastic tubing

Three temperature-compensated, differential pressure transducers suspended on 7.4 cm, outside-diameter plastic tubing

Differential pressure transducer suspended inside a 6.1-cm-diameter plastic tube, 406.6 m below the top of the tube

Three temperature-compensated, differential pressure transducers suspended on 7.4 cm, outside-diameter plastic tubing

Differential pressure transducer suspended inside a 7.4 cm, outside-diameter plastic tube, 408.4 m below the top of the tube

Differential pressure transducer suspended inside a 6.1-cm-diameter plastic tube, 432.8 m below the top of the tube

Differential pressure transducers suspended inside a 7.4-cm, outside-diameter plastic tube, 413.0 and 417.3 m below the top of the tube

Differential pressure transducer suspended inside a 6.1-cm-diameter plastic tube, 417.3 m below the top of the tube

Data acquisition

TABLE 8. INSTRUMENTATION IN THE C-HOLES FOR HYDRAULIC TESTS CONDUCTED 1984–1998

Personal computer

Personal computer

Personal computer

Electronic data logger

Electronic data logger

Electronic data logger

Electronic data logger

Electronic data logger

Electronic data logger

Electronic data logger

Electronic data logger

Data recorder

Implications for groundwater flow in the Southwest Nevada Volcanic Field 45

531.3–533.1, 605.6–607.5, 696.5–698.3, 791.9–793.7, 869.6–871.4

547.4–549.3, 605.3–607.2, 698.3–700.1, 797.1–798.9, 869.9–871.7

UE-25 c#2

UE-25 c#1

531.3–533.1, 605.6–607.5, 696.5–698.3, 869.6–871.4

547.4–549.3, 605.3–607.2, 698.3–700.1, 869.9–871.7

UE-25 c#2

UE-25 c#1

694.6–696.5, 812.9–814.7, 878.1–880.0

531.3–533.1, 605.6–607.5, 696.5–698.3, 791.9–793.7, 869.6–871.4

547.4–549.3, 605.3–607.2, 698.3–700.1, 797.1–798.9, 869.9–871.7

UE-25 c#3

UE-25 c#2

UE-25 c#1

May 8, 1996–November 12, 1997

540.4–542.2, 609.9–611.7, 695.0–696.8, 877.5–879.4

UE-25 c#3

February 8–13, 1996

No packers

Not applicable

Not applicable

Submersible pump suspended on 7.3-cm-diameter drill tubing, with an intake depth of ~650 m

Not applicable

Not applicable

Submersible pump suspended on offset from 7.3-cm-diameter drill tubing, with an intake depth of ~450 m

Not applicable

Not applicable

Submersible pump attached to 13.9cm-diameter drill tubing, with an intake depth at 450.1 m

Pump

Not applicable

Not applicable

Flowmeter inside a 15cm-diameter discharge line

Not applicable

Not applicable

Flowmeter inside a 15cm-diameter discharge line

Not applicable

Not applicable

Flowmeter inside a 15cm-diameter discharge line

Flow measurement

Temperature-compensated, absolute pressure transducers suspended on 7.3-cm-diameter drill tubing at depths of 552.1, 610.0, and 703.0 m

Temperature-compensated, absolute pressure transducers suspended on 7.3-cm-diameter drill tubing at depths of 519.8, 536.3, 610.7, and 701.6 m

Temperature-compensated, absolute pressure transducers suspended on 7.3-cm-diameter drill tubing at depths of 691.3, 708.9, and 819.3 m

Temperature-compensated, absolute pressure transducers suspended on 7.3-cm-diameter drill tubing at depths of 552.1, 610.0, and 703.0 m

Temperature-compensated, absolute pressure transducers suspended on 7.3-cm-diameter drill tubing at depths of 519.8, 536.3, 610.7, and 701.6 m

Temperature-compensated, absolute pressure transducers suspended on 7.3-cm-diameter drill tubing at depths of 533.8, 614.5, and 817.7 m

Temperature-compensated, absolute pressure transducers suspended on 7.3-cm-diameter drill tubing at depths of 552.1, 610.0, and 703.0 m

Temperature-compensated, absolute pressure transducers suspended on 7.3-cm-diameter drill tubing at depths of 519.8, 536.3, 610.7, and 701.6 m

Temperature-compensated, absolute pressure transducer suspended on 14-cm-diameter drill tubing at a depth of 441.1 m

Data acquisition

TABLE 8. INSTRUMENTATION IN THE C-HOLES FOR HYDRAULIC TESTS CONDUCTED 1984–1998 (continued)

Packer depths (m)

UE-25 c#3

June 12–22, 1995

Borehole

Personal computer

Personal computer

Personal computer

Personal computer

Personal computer

Personal computer

Personal computer

Personal computer

Personal computer

Data recorder

46 A.L. Geldon

487.7–489.5, 533.1–534.9, 605.6–607.5, 612.0–613.9

547.4–549.3, 605.3–607.2, 698.3–700.1, 797.1–798.9, 869.9–871.7

UE-25 c#2

UE-25 c#1

487.7–489.5, 533.1–534.9, 605.6–607.5, 612.0–613.9

547.4–549.3, 605.3–607.2, 698.3–700.1, 797.1–798.9, 869.9–871.7

UE-25 c#2

UE-25 c#1

Not applicable

Submersible pump suspended on 7.3-cm-diameter drill tubing, with an intake depth of 599.8 m

Positive displacement pump at land surface

Not applicable

Submersible pump suspended on 7.3-cm-diameter drill tubing, with an intake depth of 599.8 m

Not applicable

Pump

Note: Information from Geldon, 1996; Geldon et al., 1998, 1999, 2002.

473.3–475.2, 540.4–542.2, 609.9–611.7, 616.0–624.3

UE-25 c#3

June 11 to September 1, 1998

473.3–475.2, 540.4–542.2, 609.9–611.7, 616.0–624.3

Packer depths (m)

UE-25 c#3

June 2–11, 1998

Borehole

Not applicable

Flowmeter inside a 15cm-diameter discharge line

Inline flowmeter

Not applicable

Flowmeter inside a 15cm-diameter discharge line

Not applicable

Flow measurement

Temperature-compensated, absolute pressure transducers suspended on 7.3-cm-diameter drill tubing at depths of 552.1, 610.0, and 703.0 m

Temperature-compensated, absolute pressure transducers suspended on 7.3-cm-diameter drill tubing at depths of 485.8, 587.0, 588.6, and 615.7 m

Temperature-compensated, absolute pressure transducers suspended on 7.3-cm-diameter drill tubing at depths of 471.5, 591.6, 593.4, and 619.7 m

Temperature-compensated, absolute pressure transducers suspended on 7.3-cm-diameter drill tubing at depths of 552.1, 610.0, and 703.0 m

Temperature-compensated, absolute pressure transducers suspended on 7.3-cm-diameter drill tubing at depths of 485.8, 587.0, 588.6, and 615.7 m

Temperature-compensated, absolute pressure transducers suspended on 7.3-cm-diameter drill tubing at depths of 471.5, 591.6, 593.4, and 619.7 m

Data acquisition

TABLE 8. INSTRUMENTATION IN THE C-HOLES FOR HYDRAULIC TESTS CONDUCTED 1984–1998 (continued)

Personal computer

Personal computer

Personal computer

Personal computer

Personal computer

Personal computer

Data recorder

Implications for groundwater flow in the Southwest Nevada Volcanic Field 47

48

A.L. Geldon TABLE 9. INTERVAL DISCHARGES 5800 MIN AFTER PUMPING STARTED, HYDRAULIC TESTS IN UE-25 C#3, JUNE 1995 TO NOVEMBER 1997 June 1995

Hydrogeologic Unit

February 1996

May 1996 to November 1997

Discharge (L/s)

Drawdown (cm)

Flow (%)

Discharge (L/s)

Drawdown (cm)

Flow (%)

Discharge (L/s)

Drawdown (cm)

Flow (%)

UE-25 c#1 Calico Hills Prow Pass Upper Bullfrog Lower Bullfrog Bullfrog-Tram Upper Tram Lower Tram

22.5 22.5 22.5 22.5 22.5 22.5 22.5

N/D 43.0 52.1 49.7 N/D N/D N/D

3.8 2.9 3.9 68.3 89.4 21.1 trace

8.45 8.45 8.45 8.45 8.45 8.45 8.45

N/D 14.0 21.6 N/D 19.5 N/D N/D

0.5E 2.5 4.3 N/D 92.7 N/D trace

9.72 9.72 9.72 9.72 9.72 9.72 9.72

N/D 14.9 19.2 21.0 N/A N/D N/D

1.1E 2.3 3.3 66.8 N/A 26.5 trace

UE-25 c#2 Calico Hills Prow Pass Upper Bullfrog Lower Bullfrog Bullfrog-Tram Upper Tram Lower Tram

22.5 22.5 22.5 22.5 22.5 22.5 22.5

351.7 75.6 62.2 49.4 N/D 283.2 239.6

3.8 2.9 3.9 68.3 89.4 21.1 trace

8.45 8.45 8.45 8.45 8.45 8.45 8.45

16.4 14.6 25.0 N/D 21.0 N/D N/D

0.5 1.5 4.2 N/D 93.8 N/D trace

9.72 9.72 9.72 9.72 9.72 9.72 9.72

43.0 22.2 26.5 21.9 N/A N/D N/D

1.1 2.0 3.8 70.2 N/A 22.9 trace

Note: Flow proportion for the Bullfrog-Tram interval shown in June 1995 is the sum of values for the Lower Bullfrog and Upper Tram intervals. L/s—liters per second. E—estimated. N/A—not applicable. N/D—no data.

(no response was detected in UE-25 WT#3 and UE-25 WT#14). Many aspects of this test were discussed previously in the section titled “Groundwater in the Younger Tertiary Tuff and Lava Flows Hydrostratigraphic Unit.” This test was conceived mainly to quantify hydraulic properties of the composite thickness of Miocene volcanic rocks in the saturated zone at the C-holes complex, in order to validate subsequent determinations of hydraulic properties of selected intervals at this site. Only aspects of this test related to determining hydraulic properties of the Miocene volcanic rocks at the C-holes complex are discussed in this section. Each of the C-holes was open for its entire thickness below the bottom of casing and cement in the Calico Hills Formation and the Prow Pass, Bullfrog, and Tram Tuffs. Borehole UE-25 c#3 was open from 417.0 to 900.4 m below land surface. The total thickness of transmissive intervals in the borehole during the test was determined from borehole flow surveys, fracture logs, thermal gradient inflections, and low-resistivity intervals to be 274 m (Geldon, 1996). Borehole UE-25 c#2, 29.0 m from UE-25 c#3, was open from 416.0 to 910.1 m below land surface. The total thickness of transmissive intervals in UE-25 c#2 during the test was determined with the same methods used for UE-25 c#3 to be 165 m (Geldon, 1996). Borehole UE-25 c#1, 82.6 m from UE-25 c#3, was open from 417.9 to 897.6 m below land surface. The total thickness of transmissive intervals in UE-25 c#1 during the test was determined with the same methods used for UE-25 c#3 to be 252 m (Geldon, 1996). Pumping started at 14:58 on May 22, 1995, and continued without interruption until 15:01 on June 1, 1995, a period of 10 days (14,403 min). The average discharge from UE-25 c#3 during the test was 17.9 L/s, which caused 7.76 m of drawdown in

the well (Fig. 35B). Ninety percent of this drawdown occurred within 10 min of starting the pump. Recovery after the pump was shut off was equally rapid. It is estimated that 83% of the drawdown in UE-25 c#3 was caused by well losses. Drawdown in UE-25 c#2 was detected 1 min after pumping started, and drawdown in UE-25 c#1 was detected 1.5 min after pumping started. Drawdown in UE-25 c#2 reached 0.32 m after 10 days of pumping (Fig. 15). Contrary to expectations in a homogeneous, isotropic, confined aquifer, drawdown in UE-25 c#1 exceeded that in the closer observation well, UE-25 c#2, and reached 0.42 m after 10 days of pumping (Fig. 15). Recovery in UE-25 c#2 was complete on June 11, 13,600 min after pumping stopped (Geldon et al., 1998). Recovery in UE-25 c#1 was complete on June 9, 11,400 min after pumping stopped (Fig. 16). Drawdown in UE-25 c#2 was characteristic of an unconfined aquifer, which was expected because the water table is only 14 m above the top of the interval open to the well. Drawdown data plotted as a function of time since pumping started matched the type curve of Neuman (1975) for β = 0.004 (Fig. 41). This analysis indicated transmissivity of 2100 m2/d, horizontal hydraulic conductivity of 13 m/d, vertical hydraulic conductivity of 1.7 m/d, storativity of 0.003, and a specific yield of 0.2. With the water table 16 m above the top of the interval open to the well, recovery in UE-25 c#1 also was characteristic of an unconfined aquifer. Recovery data plotted as a function of time since pumping stopped matched the type curve of Neuman (1975) for β = 0.004 (Fig. 16). This analysis indicated transmissivity of 1800 m2/d, horizontal hydraulic conductivity of 7.3 m/d, vertical hydraulic conductivity of 0.3 m/d, storativity of 0.001, and a specific yield of 0.01.

Implications for groundwater flow in the Southwest Nevada Volcanic Field

49

DRAWDOWN, IN METERS

1

0.1

Late-time Match Point

Early-time Match Point

Figure 41. Analysis of drawdown in borehole UE-25 c#2 by the method of Neuman (1975), pumping test in UE-25 c#3, Yucca Mountain, May 22–June 1, 1995 (Geldon et al., 1998).

0.01

DATA TYPE CURVE

0.001 1

10

100

1000

10000

100000

TIME SINCE PUMPING STARTED, IN MINUTES

Miscellaneous Hydraulic Tests at the C-holes Complex, 1984–1998 Six hydraulic tests that were conducted at the C-holes complex between 1984 and 1998 show a typical range in hydraulic properties that can be present in the Younger Tertiary tuff and lava flows HSU at a single site. Five of these tests are discussed briefly below. A test conducted from 1996 to 1997 is discussed in the next section because of its broader scope. A pumping test conducted May 4 to June12, 1984, (Table 8) determined hydraulic properties of the Calico Hills Formation in UE-25 c#1 (Geldon, 1996). The pumping well, UE-25 c#3, was open from 417.0 to 914.4 m in the Calico Hills Formation and the Prow Pass, Bullfrog, and Tram Tuffs. UE-25 c#1, 78.9 m from UE-25 c#3, was open from 417.9 to 486.2 m in nonwelded tuff of the Calico Hills Formation and from 486.2 to 512.1m in bedded tuff of the Calico Hills Formation. Flow surveys and other geophysical logs indicated that 55.5 m of nonwelded tuff and 4.9 m of bedded tuff in packed-off intervals of UE-25 c#1 were transmissive (Geldon, 1996). Pumping started at 22:57 on May 4, shut off for 163 min on May 9 (6520 min into the test), and terminated at 10:02 on May 14. Discharge, which averaged 26.4 L/s for the 13,625 min that the pump was operating, caused 3.35–5.49 m of drawdown in the two intervals of the Calico Hills Formation that were monitored in UE-25 c#1. Recovery from pumping was monitored from May 14 to June 12. Drawdown in the nonwelded tuff interval of the Calico Hills Formation in UE-25 c#1 and recovery in the bedded tuff interval of the Calico Hills Formation in UE-25 c#1 were analyzed. With the water table in the Calico Hills Formation, drawdown and recovery in UE-25 c#1 conformed to unconfined aquifer type curves of Neuman (1975). A pumping test conducted October 30 to December 7, 1984 (Table 8) determined hydraulic properties of the Tram Tuff in

UE-25 c#1 (Geldon, 1996). The pumping well, UE-25 c#3, was open from 417.0 to 907.1 m in the Calico Hills Formation and the Prow Pass, Bullfrog, and Tram Tuffs. UE-25 c#1, 85.3 m from UE-25 c#3, was open from 793.4 to 902.8 m in the Tram Tuff. Flow surveys and other geophysical logs indicated that 63.4 m of the Tram Tuff in UE-25 c#1 were transmissive (Geldon, 1996). Pumping started at 17:56 on October 30, shut off for 8.3 min on November 2 (3839 min into the test), and terminated at 13:42 on November 15. Discharge, which averaged 26.8 L/s over a period of 15.8 days (22,786 min), caused 0.96 m of drawdown in the Tram Tuff in UE-25 c#1. Drawdown became essentially constant after ~5000 min of pumping apparently as a result of recharge from the Midway Valley Fault. Recovery from pumping was monitored from November 15 to December 7, but it was complete by November 28. Drawdown was analyzed by the method of Cooper (1963) for leakage from a confining layer without storage (Fig. 17), a situation analogous to fault recharge. A pumping test conducted June 12–22, 1995, (Table 8) determined hydraulic properties of the Calico Hills, Prow Pass, Upper Bullfrog, and Lower Bullfrog intervals in UE-25 c#2 and UE-25 c#1 (Geldon et al., 2002). The pumping well, UE-25 c#3, was open from 417.0 to 900.4 m in the Calico Hills Formation and the Prow Pass, Bullfrog, and Tram Tuffs. UE-25 c#2, 28.6–29.3 m from UE-25 c#3 at depths tested, was open from 416.0 to 531.3 m in the Calico Hills interval, from 533.1 to 605.6 m in the Prow Pass interval, from 607.5 to 696.5 m in the Upper Bullfrog interval, and from 698.3 to 791.9 m in the Lower Bullfrog interval. Flow surveys and other geophysical logs indicated that 45.4 m of the Calico Hills interval, 23.8 m of the Prow Pass interval, 24.1 m of the Upper Bullfrog interval, and 29.9 m of the Lower Bullfrog interval in UE-25 c#2 were transmissive. UE-25 c#1, 78.3–85.6 m from UE-25 c#3 at depths tested, was open from 549.3 to 605.3 m in the

50

A.L. Geldon

Prow Pass interval, from 607.2 to 698.3 m in the Upper Bullfrog interval, and from 700.1 to 797.1 m in the Lower Bullfrog interval. Flow surveys and other geophysical logs indicated that 18.9 m of the Prow Pass interval, 46.0 m of the Upper Bullfrog interval, and 62.8 m of the Lower Bullfrog interval in UE-25 c#1 were transmissive. Pumping started at 14:24 on June 12 and continued without interruption until 15:07 on June 16. Discharge, which averaged 22.5 L/s over a period of 4.0 days (5803 min), caused 10.9 m of drawdown in the pumped well, 0.49–35.2 m of drawdown in intervals of UE-25 c#2, and 0.43–0.52 m of drawdown in intervals of UE-25 c#1. Recovery from pumping was monitored June 16–22. Drawdown and recovery in the Calico Hills interval conformed to type curves of Neuman (1975) for an unconfined aquifer. Drawdown and recovery in all other intervals conformed to the exponential integral curve of Theis (1935) for a homogeneous, isotropic, confined aquifer. Figures 42–45 are representative analyses of drawdown and recovery from this test. A pumping test conducted February 8–13, 1996, (Table 8) determined hydraulic properties of the combined Lower Bullfrog and Upper Tram intervals in UE-25 c#1 and UE-25 c#2, from which it was possible using data from the previous test to separate properties of the Upper Tram intervals in UE-25 c#1 and UE-25 c#2 (Geldon et al., 2002). The pumping well, UE-25 c#3, was open from 696.8 to 877.5 m in the Bullfrog-Tram interval (the combined Lower Bullfrog and Upper Tram intervals). UE25 c#2, 29.0 m from UE-25 c#3, was open in the Bullfrog-Tram interval from 698.3 to 869.6 m, and UE-25 c#1, 86.3 m from

UE-25 c#3, was open in the Bullfrog-Tram interval from 700.1 to 869.9 m. Flow surveys and other geophysical logs indicated that the Bullfrog-Tram interval had a transmissive thickness of 51.2 m in UE-25 c#2 and 112 m in UE-25 c#1. Pumping started at 13:55 on February 8 and continued without interruption until 10:18 on February 13. Discharge, which averaged 8.49 L/s over a period of 4.85 days (6984 min), caused 2.86 m of drawdown in the pumped well, 0.21 m of drawdown in UE-25 c#2, and 0.18 m of drawdown in UE-25 c#1. Recovery data were not obtained because the pumping test was terminated by a tracer test. Drawdown in both observation wells appeared to conform to the exponential integral curve of Theis (1935) for a homogeneous, isotropic, confined aquifer. A pumping test conducted June 2–11, 1998, (Table 8) determined hydraulic properties of the Prow Pass interval in UE-25 c#1 and UE-25 c#3 (Geldon et al., 1999). The pumping well, UE-25 c#2, was open from 485.9 to 605.6 m in the Prow Pass interval. UE-25 c#3, 28.7 m from UE-25 c#2, was open from 542.2 to 609.9 m in the Prow Pass interval, and UE-25 c#1, 82.6 m from UE-25 c#2, was open from 549.2 to 605.3 m in this interval. Flow surveys and other geophysical logs indicated that the Prow Pass interval had a transmissive thickness of 31.7 m in UE-25 c#3 and 18.9 m in UE-25 c#1. Discharge, which averaged 0.33 L/s over a period of 8.68 days (12,500 min), caused 128 m of drawdown in the pumped well, 0.54 m of drawdown in UE-25 c#3, and 0.12 m of drawdown in UE-25 c#1. Recovery data were not obtained because the pumping test was terminated by a tracer test. Draw-

10

DRAWDOWN, IN METERS

Early-time Match Point

1

Figure 42. Analysis of drawdown in UE-25 c#2 Calico Hills interval by the method of Neuman (1975), pumping test in UE-25 c#3, June 12–16, 1995. (Data from Geldon et al., 2002.)

0.1

DATA TYPE CURVE 0.01 1

10

100

1000

TIME SINCE PUMPING STARTED, IN MINUTES

10000

Implications for groundwater flow in the Southwest Nevada Volcanic Field

51

DRAWDOWN, IN METERS

1

Match Point 0.1

Figure 43. Analysis of drawdown in UE25 c#1 Prow Pass interval by the method of Theis (1935), pumping test in UE-25 c#3, June 12–16, 1995. (Modified from Geldon et al., 2002.)

0.01

DATA TYPE CURVE 0.001 1

10

100

1000

10000

TIME SINCE PUMPING STARTED, IN MINUTES

DRAWDOWN, IN METERS

10

1

0.1

Figure 44. Analysis of drawdown in UE-25 c#2 Upper Bullfrog interval by the method of Theis (1935), pumping test in UE-25 c#3, June 12–16, 1995. (Modified from Geldon et al., 2002.)

Match Point

DATA TYPE CURVE 0.01 1

10

100

1000

TIME SINCE PUMPING STARTED, IN MINUTES

10000

52

A.L. Geldon

RECOVERY, IN METERS

1

Match Point

0.1

Figure 45. Analysis of drawdown in UE-25 c#1 Lower Bullfrog interval by the method of Theis (1935), pumping test in UE-25 c#3, June 12–16, 1995. (Modified from Geldon et al., 2002.)

0.01

DATA TYPE CURVE 0.001 0.1

1

10

100

1000

10000

TIME SINCE PUMPING STOPPED, IN MINUTES

down in both observation wells conformed to type curves of Cooper (1963) for a leaky, confined aquifer. Transducers above and below the Prow Pass interval indicated that this leakage appeared to be coming from the Calico Hills interval in UE-25 c#3 and both the Calico Hills and upper Bullfrog intervals in UE-25 c#1. Table 10 summarizes hydraulic properties of intervals in the C-holes that were determined from hydraulic tests discussed in this section. In general, these tests showed that most transmissive intervals in the C-holes are confined, but the Calico Hills interval, near the water table, is unconfined, and the Tram Tuff receives recharge from the cross-cutting Midway Valley Fault. The Calico Hills interval is the least transmissive interval, because it is the farthest interval vertically from the Midway Valley Fault. The Lower Bullfrog and Upper Tram intervals are the most transmissive intervals because they are nearest vertically to the Midway Valley Fault. The Prow Pass and Upper Bullfrog intervals consistently had the smallest storativity, possibly because fractures are responsible for most flow from these intervals. Pumping Test in UE-25 c#3, May 8, 1996, to November 12, 1997 A pumping test was conducted in borehole UE-25 c#3 from May 8, 1996, to November 12, 1997 (Table 8), after which recovery was monitored until December 31, 1997 (Geldon et al., 2002). The pumping was intended to establish a steep, quasi–steady-state hydraulic gradient for tracer tests that began May 15, 1996, and it was expected that tracer-test operations would terminate the record that could be analyzed as a pumping test. Neither tracer tests nor unplanned pump shut-offs were found to affect records of drawdown in observation wells long enough to hinder their analysis for most of the time that UE-25 c#3 was pumped. The pumping test was planned to quantify hydraulic properties of the

Lower Bullfrog interval in the C-holes, which was accomplished, but pumping much longer than in any previous test at the site changed perceptions about flow in this transmissive interval and required previously unanticipated analytical methods to determine hydraulic properties. Although water was pumped from the lower Bullfrog Tuff, observation wells open in the Topopah Spring Tuff, Calico Hills Formation, and the Prow Pass, Bullfrog, Tram, and Lithic Ridge Tuffs in an 81 km2 area were affected by pumping. This test, which is termed the lower Bullfrog test in this report, demonstrated conclusively that the diverse geologic units affected by the pumping comprise a single HSU (the Younger Tertiary tuff and lava flows HSU) and not separate aquifers and confining layers, as previously thought by Winograd and Thordarson (1975), Luckey et al. (1996), and other workers in the area. The test also delineated boundaries of the Yucca Mountain hydrologic domain, and it established that the Midway Valley Fault is a recharge boundary. This last aspect of the lower Bullfrog test was discussed thoroughly in the section titled “Groundwater in the Younger Tertiary Tuff and Lava Flows Hydrostratigraphic Unit” and will not be addressed further in this section of the report. The monitoring network for the lower Bullfrog test initially consisted of the pumping well, UE-25 c#3, and six continuously monitored observation wells, UE-25 c#2, UE-25 c#1, UE-25 ONC#1, UE-25 WT#3, UE-25 WT#14, and USW H-4 (Fig. 20). The test persisted long enough that 16 wells included in a network established at Yucca Mountain for periodic measurements of water levels (Graves, 1998, 2000) could be incorporated into the test monitoring network (Geldon, 1999). The additional observation wells were J-12, J-13, USW G-2, USW H-1, USW H-3, USW H-5, USW H-6, USW WT-1, UE-25 WT#4, USW WT-7, USW WT-10, USW WT-11, UE-25 WT#13, UE-25

Implications for groundwater flow in the Southwest Nevada Volcanic Field

53

TABLE 10. SUMMARY HYDRAULIC-PROPERTY DATA FOR TRANSMISSIVE INTERVALS IN THE C-HOLES DETERMINED FROM PUMPING TESTS CONDUCTED MAY 1984 TO JUNE 1998 Interval

Borehole

Transmissive thickness (m)

Percent flow

Test date

Transmissivity (m2/day)

Hydraulic conductivity (m/day)

Storativity or specific yield

Aquifer type

Calico Hills

UE-25 c#1 UE-25 c#2

60.4 45.4

4.5 3.8

May 4, 1984 June 12, 1995

9.3 5.5

0.15 0.12

0.003 (sy) 0.02 (sy)

Unconfined Unconfined

Prow Pass

UE-25 c#1 UE-25 c#2 UE-25 c#1 UE-25 c#3

18.9 23.8 18.9 31.7

2.9 2.9 N/A N/A

June 12, 1995 June 12, 1995 June 2, 1998 June 2, 1998

60 40 65 17

3.4 1.7 3.4 0.55

0.0003 0.0004 0.00001 0.00005

Confined Confined Leaky confined Leaky confined

Upper Bullfrog

UE-25 c#1 UE-25 c#2

46.0 24.1

3.9 3.9

June 12, 1995 June 12, 1995

90 100

2.0 4.2

0.00006 0.00003

Confined Confined

Lower Bullfrog

UE-25 c#1 UE-25 c#2

62.8 29.9

68.3 68.3

June 12, 1995 June 12, 1995

1,800 1,900

29 64

0.0004 0.003

Confined Confined

Tram

UE-25 c#1 UE-25 c#1 UE-25 c#2

63.4 49.7 (upper) 21.3 (upper)

58.0 21.1 21.1

October 30, 1984 February 8, 1996 February 8, 1996

730 700 600

12 13 28

0.003 0.0001 0.0008

Leaky confined Confined Confined

Note: N/A—not applicable; sy—specific yield.

WT#15, UE-25 WT#16, and UE-25 b#1 (Fig. 20). Completion data for all of the monitored wells, except six that did not respond to pumping in any test included in the study database (Appendix B)—USW WT-7, USW WT-10, UE-25 WT#13, UE-25 WT#15, UE-25 WT#16, and J-12—are listed in Table 4. Graves (1998) contains completion data for the six wells omitted from Table 4. Table 8 contains descriptions of instrumentation in the C-holes during this test; Nye County Nuclear Waste Repository Project Office (1995) contains a description of instrumentation in UE-25 ONC#1; Graves (1998, 2000) contains descriptions of instrumentation in all other monitoring wells used in this test. The 12 wells that responded to pumping are discussed briefly below before presenting analyses and interpretations of this test. Each of the C-holes was open between straddle packers in the lower Bullfrog interval. UE-25 c#3 was open between depths of 696.5 and 812.9 m, where flow surveys and other geophysical logs indicated 66.4 m of transmissive rock. UE-25 c#2, 29.3 m from UE-25 c#3, was open between depths of 698.3 and 791.9 m, where flow surveys and other geophysical logs indicated 29.9 m of transmissive rock. UE-25 c#1, 85.6 m from UE-25 c#3, was open between depths of 700.1 and 797.1 m, where flow surveys and other geophysical logs indicated 62.8 m of transmissive rock. Borehole UE-25 ONC#1, 842.8 m from UE-25 c#3, was open between depths of 453.2 and 469.4 m in the Prow Pass Tuff (Nye County Nuclear Waste Repository Project Office, 1995). Water movement through the Bullfrog Tuff must have occurred to establish hydraulic connection to the pumping well during the test. The thickness of transmissive rock between the observation and pumping wells cannot be established with any certainty, but it was estimated on the basis of assumed linear variation between transmissive thicknesses in UE-25 c#2 and USW H-4 to be 90 m.

Borehole USW WT-1, 1992 m from UE-25 c#3, was open between depths of 470.8 and 514.8 m in the Calico Hills Formation and Bullfrog Tuff (Nelson et al., 1991). The total thickness of transmissive rock between USW WT-1 and UE-25 c#3 was estimated to be 65 m on the basis of the geology between the two boreholes and the thickness of transmissive rock in UE-25 c#3. Borehole USW H-4, 2245 m from UE-25 c#3, was open between depths of 560.5 and 1181.5 m in the Prow Pass, Bullfrog, and Tram Tuffs (Whitfield et al., 1985). A tracejector flow survey conducted in May 1982 indicated that the total thickness of transmissive rock in the Prow Pass and Bullfrog Tuffs is 111 m (Whitfield et al., 1985). Although the Tram Tuff contains 3 transmissive intervals between depths of 820 and 922 m in USW H-4, it was assumed that flow to the pumping well was radial and, therefore, that these intervals did not contribute flow to the pumping well. If the Tram Tuff in USW H-4 contributed flow in this test, hydraulic conductivity would be smaller than calculated in analyses of data from USW H-4. Borehole UE-25 WT#14, 2249 m from UE-25 c#3, was open between depths of 346.4 and 399.3 m in the Topopah Spring Tuff and the Calico Hills Formation (Nelson et al., 1991). Water movement through the Prow Pass and Bullfrog Tuffs must have occurred to establish hydraulic connection to the pumping well during the test. A total transmissive thickness of 170 m was estimated by comparison with the hydrogeology of nearby UE25 p#1 (Craig and Robison, 1984). Borehole UE-25 b#1, 2722 m from UE-25 c#3, was open between depths of 470.1 and 1219.8 m in the Calico Hills Formation, Prow Pass Tuff, and Bullfrog Tuff (Lobmeyer et al., 1983; Lahoud et al., 1984). A tracejector flow survey conducted in August 1981 (Fig. 26 B) indicated 109 m of transmissive rock in this well.

54

A.L. Geldon

Borehole UE-25 WT#3, 3526 m from UE-25 c#3, was open between depths of 300.4 and 348.1 m in the Bullfrog Tuff (Nelson et al., 1991). A total transmissive thickness of 52 m was estimated by comparison with the hydrogeology of nearby UE25 p#1 (Craig and Robison, 1984). Borehole UE-25 WT#4, 3573 m from UE-25 c#3, was open between depths of 438.4 and 481.6 m in the Calico Hills Formation (Nelson et al., 1991). Water movement through the Prow Pass and Bullfrog Tuffs must have occurred to establish hydraulic connection to the pumping well during the test. A total transmissive thickness of 109 m was estimated by comparison with the hydrogeology of nearby UE-25 b#1. Borehole USW H-1, 4625 m from UE-25 c#3, was open in the Prow Pass Tuff between depths of 572 and 673 m and in the Bullfrog Tuff between depths of 716 and 765 m (Rush et al., 1984). Tracejector flow surveys conducted in October and December 1982 indicated 103 m of transmissive rock in this well (Rush et al., 1984). Borehole USW WT-11, 6414 m from UE-25 c#3, was open between depths of 363.5 and 440.7 m in the Topopah Spring Tuff and the Calico Hills Formation (Nelson et al., 1991). Water movement through the Prow Pass and Bullfrog Tuffs must have occurred to establish hydraulic connection to the pumping well during the test. A total transmissive thickness of 109 m was estimated from the site geology and transmissive thicknesses determined for boreholes UE-25 b#1, USW H-4, and UE-25 WT#14. Pumping in the lower Bullfrog test began at 11:17 on May 8, 1996. Tracers were injected into the lower Bullfrog intervals in either UE-25 c#2 or UE-25 c#1 on May 15, June 18, and October 9, 1996 and on January 9 and 10, 1997. Tracer injections generally disturbed water levels for 1–6 days, although recirculation of water between the injection and recovery wells in one test caused water levels in the injection well to rise for 16 days. The pump went down 11 times for periods of 2–185 min between May 24, 1996, and March 26, 1997, frequently between March 26 and May 8, 1997, seven times between May 30 and September 29, 1997, and at least once a day between October 15 and November 12, 1997. The pumping and tracer tests were terminated because of irresolvable generator problems at 16:00 on November 12, 1997, 553 days (796,663 min) after pumping started. Discharge from UE-25 c#3 averaged 9.53 L/s between May 8, 1996, and March 26, 1997, but it fluctuated erratically March 26–May 8, 1997, and decreased steadily from 9.3 to 8.9 L/s thereafter because of generator problems. Discharge averaged 9.21 L/s for the entire test. Pump shutoffs typically caused rapid and nearly complete recovery in UE-25 c#3, but these effects were reversed just as rapidly when pumping resumed. Tracer test operations affected drawdown in the pumping well minimally. The frequent pump shutoffs prevented drawdown in UE-25 c#3 from exceeding 5.98 m, which was reached on March 26, 1997, 464,134 min after pumping started. On the basis of hydraulic properties determined from this test, it is estimated that 80% of the drawdown in UE-25 c#3 was caused by well losses. Recovery in UE-25 c#3 was complete on December 12, 1997, 29.8 days after pumping stopped.

Analyzable drawdown records for 11 observation wells in the lower Bullfrog test ranged from 300,000–796,663 min. Only UE25 ONC#1 had a usable, continuous record for the entire 796,663 min of pumping. Drawdown in 10 other wells was extrapolated to the end of pumping using hydraulic properties determined during the test. Measured and extrapolated drawdown in these 11 wells ranged from 0.14 to 0.47 m (Fig. 46). Drawdown clearly was influenced by the northwesterly trending Drill Hole Wash Fault in the vicinity of boreholes UE-25 b#1, UE-25 WT#4, and USW H-1, but the drawdown distribution appears to have been influenced mainly by north-northeasterly trending faults, such as the Paintbrush Canyon, Midway Valley, and Bow Ridge Faults (See Figure 39 for locations of faults). As shown in Figures 20 and 46, lines separating observation wells that did not respond to pumping—J-12, J-13, UE-25 WT#13, UE-25 WT#15, UE-25 WT#16, USW G-2, USW H-5, USW H-6, USW H-3, USW WT-7, and USW WT-10—from wells that responded to pumping generally coincide with traces of faults that delineate the northern boundaries of the Yucca Mountain hydrologic domain. Figure 46 appears to indicate that the lower Bullfrog test affected most of the Yucca Mountain hydrologic domain, as it was defined previously in this report. Drawdown in the Lower Bullfrog intervals in UE-25 c#1 and UE-25 c#2 during the lower Bullfrog test is different in several ways from drawdown in these intervals that was observed during previous hydraulic tests of much shorter duration. As shown in Figure 47, drawdown after 158,000 min increased at a faster rate than could be anticipated by extrapolation of earlier drawdown using analytical equations by Theis (1935), Equations 1 and 3 in this report. The larger-than-anticipated drawdown during the latter part of the test indicates that the spreading cone of depression encompassed less transmissive rock as the test progressed. Although previous tests indicated a confined-aquifer response to pumping, the lower Bullfrog test progressed long enough for a double-humped drawdown curve characteristic of dual fracture and matrix permeability to develop. Consequently, drawdown trends in the Lower Bullfrog intervals of UE-25 c#2 and UE-25 c#1 in the lower Bullfrog test were analyzed by the method of Streltsova-Adams (1978). Drawdown in both UE-25 c#2 (Fig. 48) and UE-25 c#1 conformed to the type curve for η = 10 and r/b = 0.05. These analyses indicated transmissivity of 1300 m2/d, hydraulic conductivity of 20–40 m/d, matrix storativity of 0.002–0.02, and fracture storativity of 0.0002–0.002. Hydraulic conductivity and storativity were larger in a west-northwesterly direction, parallel to the Antler Wash Fault zone than in a northnortheasterly direction, parallel to the Midway Valley Fault. Average hydraulic properties of Miocene volcanic rocks within the part of the Yucca Mountain hydrologic domain affected by the lower Bullfrog test were determined in two ways: (1) by analyzing continuously recorded drawdown as a function of time in the four observation wells not affected by a recharge boundary (UE-25 c#1, UE-25 c#2, UE-25 ONC#1, and UE-25 WT#3); and (2) by analyzing drawdown in all of the observation wells except USW WT-1 as a function of distance from the pumping well before the recharge boundary was encountered. Table 11 lists

4085000

Implications for groundwater flow in the Southwest Nevada Volcanic Field DRAWDOWN,

55

IN METERS

G2 WT16 H1

4080000 H5

4075000

WT15

WT10

0.35

WT14 H4 ONC1 C2 WT13 WT1 0.2 5

WT7 H3

0.2

0.30

J13

0.25

WT3

4070000

0.1 5

0.10

0.

05

0

UTM NORTH (METERS)

H6

0.40

WT4 B1

0.20

WT11 J12

Figure 46. Drawdown distribution after 796,663 min of pumping, lower Bullfrog test in UE-25 c#3, Yucca Mountain, May 8, 1996, to November 12, 1997.

0.15 0.10

4065000 0.05

4060000 535000

540000

545000

550000

555000

560000

UTM EAST (METERS)

70 Tracer injected DRAWDOWN, IN CENTIMETERS

60

Tracer injected

50 Tracer injected

40

Figure 47. Drawdown in UE-25 c#2, lower Bullfrog interval, pumping test in UE-25 c#3, May 8, 1996 to November 12, 1997. Downward spikes mostly are unplanned pump shut-offs. (Modified from Geldon et al., 2002.)

30 20 RECORDED

10 EXTRAPOLATED

0 0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

TIME SINCE PUMPING STARTED, IN MINUTES

DRAWDOWN, IN METERS

10

DATA TYPE CURVE 1

Figure 48. Analysis of drawdown in UE-25 c#2, lower Bullfrog interval, by the method of Streltsova-Adams (1978), pumping test in UE-25 c#3, May 8, 1996, to November 12, 1997. (Data from Fig. 47.)

0.1

Match Point

0.01 1

10

100

1000

10000

100000

TIME SINCE PUMPING STARTED, IN MINUTES

1000000

56

A.L. Geldon TABLE 11. HYDRAULIC PROPERTIES DETERMINED FROM DRAWDOWN IN OBSERVATION WELLS, LOWER BULLFROG TEST, MAY 8, 1996, TO NOVEMBER 12, 1997 Well

Distance to UE-25 c#3 (m)

Geologic units

T (m2/d)

K (m/d)

Storativity

Storativity, fractures

Storativity, matrix

29.3 85.6 842.8 1992 2245 2249 2722 3526 3573 4625 6414

Bullfrog Tuff Bullfrog Tuff Prow Pass and Bullfrog Tuffs Calico Hills Formation to Bullfrog Tuff Prow Pass and Bullfrog Tuffs Topopah Spring Tuff to Bullfrog Tuff Calico Hills Formation to Bullfrog Tuff Bullfrog Tuff Calico Hills Formation to Bullfrog Tuff Prow Pass and Bullfrog Tuffs Topopah Spring Tuff to Bullfrog Tuff

1,300 1,300 970 630 560 710 980 800 960 650 980

40 20 11 9.7 5.0 4.2 9.0 15 8.8 6.3 9.0

0.02 0.002 0.01 0.01 0.002 0.002 0.004 0.01 0.002 0.001 0.002

0.002 0.0002 0.001 No Data No Data No Data No Data 0.002 No Data No Data No Data

0.02 0.002 0.01 No Data No Data No Data No Data 0.01 No Data No Data No Data

UE-25 c#2 UE-25 c#1 UE-25 ONC #1 USW WT-1 USW H-4 UE-25 WT #14 UE-25 b#1 UE-25 WT #3 UE-25 WT#4 USW H-1 USW WT-11

Note: T—transmissivity; K—hydraulic conductivity; m2/d—meters squared per day; m/d—meters per day.

values of hydraulic properties determined from analyses of drawdown observed in 11 observation wells during the lower Bullfrog test for comparison with these multiple-well solutions. Figure 49 shows drawdown data for UE-25 c#2, UE-25 c#1, UE-25 ONC#1, and UE-25 WT#3 through March 26, 1997, 464,100 min after pumping started, plotted together as a function of time and matched to the type curve of Theis (1935) for a confined aquifer. This analysis indicated transmissivity of 2200 m2/d and storativity of 0.002. To calculate hydraulic conductivity,

values of transmissive thickness in the 11 observation wells that responded to pumping were plotted and contoured. An average transmissive thickness of 100 m was estimated visually from this plot and from the geometric mean of transmissive thickness values for wells listed in Table 11, 84 m. A hydraulic conductivity value of 22 m/d was calculated from the transmissivity and average transmissive thickness values. This analysis provides average values of hydraulic properties for the 21 km2 area encompassed by the observation wells involved in the analysis.

DRAWDOWN, IN METERS

1

0.1 Match Point

Figure 49. Analysis by the method of Theis (1935) of drawdown in observation wells as a function of time, pumping test in UE-25 c#3, May 8, 1996, to November 12, 1997. (Modified from Geldon et al., 2002.)

UE-25 c#2 0.01

UE-25 c#1 UE-25 ONC#1 UE-25 WT#3 TYPE CURVE

0.001 0.0001

0.001

0.01

0.1

1

10

100

1000

TIME SINCE PUMPING STARTED/DISTANCE SQUARED, IN MINUTES PER SQUARE METER

Implications for groundwater flow in the Southwest Nevada Volcanic Field Figure 50 shows drawdown data for all observation wells except USW WT-1 (an outlier) plotted together as a function of distance from UE-25 c#3 through 70,000 min of pumping (2000 min before the effects of recharge from the Midway Valley Fault became noticeable). Drawdown values in wells UE-25 c#2, UE25 ONC#1, UE-25 WT#14, USW H-4, and UE-25 WT#3 were plotted as recorded. Undisturbed drawdown in UE-25 c#1 at 70,000 min had to be estimated because of an ongoing tracer test in the well. Transmissivity and storativity determined from UE25 c#1 drawdown during the lower Bullfrog test and Equations 5 and 6 were used to estimate the undisturbed drawdown in UE25 c#1 at 70,000 min. Drawdown in the periodically monitored wells UE-25 b#1, UE-25 WT#4, USW H-1, and USW WT-11, also, had to be estimated, because water levels in these wells were not measured 70,000 min after pumping started. Drawdown in the periodically monitored wells was estimated by the same method used for UE-25 c#1. As indicated in Figure 50, a straight line with a slope of 0.129 m per log cycle of distance was fit to the drawdown data. Transmissivity and storativity were determined with equations of Cooper and Jacob (1946). Hydraulic conductivity was calculated from transmissivity using an estimated transmissive thickness of 100 m. This analysis indicated transmissivity of 2400 m2/d, hydraulic conductivity of 24 m/d, and storativity of 0.0006 for the 81 km2 area encompassed by the 11 responding observation wells. Results of this analysis were very similar to the analysis of drawdown as a function of time using multiple observation wells in this test and to the analysis of drawdown as a function of time using multiple observation wells in the test conducted May 22 to June 1, 1995.

DRAWDOWN, IN METERS

0.00 s = -0.129 x Log r + 0.555 R2 = 0.85 0.08

0.16

0.24

0.32

0.40 10

100

1000

10000

DISTANCE FROM UE-25 C#3, IN METERS

Figure 50. Analysis by the method of Cooper and Jacob (1946) of drawdown in observation wells as a function of distance from the pumping well 70,000 min after pumping started, pumping test in UE25 c#3, May 8, 1996, to November 12, 1997. (Data from Graves, 1998, 2000; U.S. Geological Survey files.)

57

Drill Hole Wash Only one cross-hole hydraulic test was conducted at Yucca Mountain at a site other than the C-holes complex. This test, a pumping test involving boreholes UE-25 a#1 and UE-25 b#1, was conducted August 29 to September 1, 1981, near the mouth of Drill Hole Wash, which is shown in Figure 39. This pumping test was described by Lahoud et al. (1984) and analyzed by Moench (1984). Moench’s analytical method assumes transient block to fracture flow impeded by “fracture skin.” A simpler analysis of this test, which does not depend on the many unverifiable assumptions used in Moench’s analysis, is discussed below. The Drill Hole Wash complex was constructed from 1978 to 1981 (Spengler et al., 1979; Lobmeyer et al., 1983). Boreholes UE-25 a#1 and UE-25 b#1, which are at altitudes of 1199–1201 m AMSL, straddle the northwesterly trending Drill Hole Wash Fault zone (Fig. 39). Borehole UE-25 a#1 is 106.8 m south-southwest of borehole UE-25 b#1 at the land surface, but interborehole distances at depth differ because the boreholes deviated during drilling. UE-25 a#1 was drilled to a depth of 762.2 m, and UE-25 b#1 was drilled to a depth of 1219.8 m, but both boreholes have collapsed tens of meters since they were drilled. Completion data for the two boreholes are listed in Table 4. The Drill Hole Wash complex was constructed in faulted Miocene volcanic rocks that are covered by a thin veneer of Quaternary alluvium. Volcanic formations known to be present at the site extend downward from the Tiva Canyon Tuff to the Lithic Ridge Tuff (Fig. 51). In both boreholes, the water table is in the Calico Hills Formation. Below the water table, the volcanic rocks consist of nonwelded to moderately welded ash-flow tuff with bedded ashfall tuff and volcaniclastic rocks. The Calico Hills Formation, Tram Tuff, and Lithic Ridge Tuff generally are zeolitized to argillized; the Prow Pass and Bullfrog Tuffs contain zeolitized intervals. The Drill Hole Wash Fault zone where it intersects boreholes UE-25 a#1 and UE-25 b#1 contains several prominent fault splays that dip at high angles to the southwest and have displaced formations down to the southwest (Fig. 51). Where two of these fault splays intersect UE-25 b#1, bedded tuff at the bottom of the Calico Hills Formation and nonwelded to partially welded tuff at the top of the Prow Pass Tuff have been cut out, and underlying partially to moderately welded tuff in the Prow Pass Tuff is brecciated and zeolitized. Another fault splay that intersects UE-25 b#1 extensively fractured moderately welded tuff in the Bullfrog Tuff. Five discrete intervals transmit water to boreholes at the Drill Hole Wash complex. These intervals were identified by a tracejector flow survey done in August 1981 during a pumping test in UE-25 b#1 (Fig. 26B). This flow survey indicated that the Calico Hills Formation produces 32% of the water in UE-25 b#1, the Prow Pass Tuff produces 19% of the water in UE-25 b#1, and the Bullfrog Tuff produces 49% of the water in UE-25 b#1. The total thickness of transmissive intervals in UE-25 b#1 is 109 m. A pumping test was conducted in borehole UE-25 b#1 from August 29 to September 1, 1981, with UE-25 a#1 used as an obser-

58

A.L. Geldon

vation well (Lahoud et al., 1984). Both boreholes were open from the water table to total depth. UE-25 b#1 was open between depths of 470.6 and 1219.8 m in the Calico Hills Formation and the Prow Pass, Bullfrog, Tram, and Lithic Ridge Tuffs. UE-25 a#1 was open from 468 to 762 m in the Calico Hills Formation and the Prow Pass and Bullfrog Tuffs. The known thickness of transmissive rock in UE-25 b#1, 109 m, was assumed for UE-25 a#1. Pumping UE-25 b#1 at an average rate of 35.7 L/s for 4200 min caused 10.4 m of drawdown in UE-25 b#1 and 0.64 m of drawdown in UE-25 a#1. As in pumping tests conducted at the C-holes complex, drawdown in the pumping well was rapid. Eighty-three percent of the drawdown in UE-25 b#1 occurred

within 10 min of starting the pump. It is estimated from hydraulic properties determined from drawdown in UE-25 a#1 in this test and from hydraulic properties determined from drawdown in UE-25 b#1 in the lower Bullfrog test that 44%–55% of the drawdown in UE-25 b#1 in this test was caused by well losses. Drawdown in UE-25 a#1 conformed to the β = 0.1 type curve of Neuman (1975) for an unconfined aquifer (Fig. 52). This analysis indicated transmissivity of 850 m2/d, horizontal hydraulic conductivity of 7.8 m/d, vertical hydraulic conductivity of 0.8 m/d, storativity of 0.0009, and a specific yield of 0.07. In comparison, Moench (1984) determined transmissivity of 350 m2/d, fracture hydraulic conductivity of 0.85 m/d, matrix

Figure 51. Geologic cross section across Drill Hole Wash, Yucca Mountain. (Compiled from Spengler and Rosenbaum, 1980; Lahoud et al., 1984.)

Implications for groundwater flow in the Southwest Nevada Volcanic Field hydraulic conductivity of 0.17 m/d, fracture storativity of 0.0006, and matrix storativity of 0.024. Analytical results indicate that volcanic rocks at Drill Hole Wash appear to be less permeable and less capable of yielding water from storage than volcanic rocks at the C-holes complex. Frenchman Flat Frenchman Flat contains one of five sites in the eastern Southwest Nevada Volcanic Field where cross-hole hydraulic tests were conducted in the Younger Tertiary tuff and lava flows HSU. A pumping test involving water wells 4 and 4a was conducted February 22–25, 1990, in the northwest corner of Frenchman Flat (Fig. 23), in an area informally known as the CP basin. A description of this pumping test has never been published. Water wells 4 and 4a, which are located at altitudes of 1098–1099 m AMSL, were drilled to supply water to Nevada Test Site facilities (Gillespie et al., 1996; Wood and Reiner, 1996). Water well 4 was drilled in 1981 to a depth of 450.8 m, but it caved below 447.4 m. It contains perforated casing from 287.1 to 437.7 m and is uncased from 438.3 to 447.4 m (Table 4). Water well 4a, 371 m southwest of water well 4, was drilled in 1990 to a depth of 462.1 m, but it caved below 457.8 m. It contains slotted casing from 324.9 to 390.4 m and from 416.0 to 444.1 m and is uncased from 457.5 to 457.8 m (Table 4). Water wells 4 and 4a are completed in Miocene volcanic rocks, which are covered by Quaternary-Tertiary alluvium that thickens from 158 to 226 m toward the southwest (Gillespie

59

et al., 1996; Warren et al., 1998). Volcanic formations known to be present beneath the alluvium extend downward from the Ammonia Tanks Tuff to the Prow Pass Tuff. The water table is in the Ammonia Tanks Tuff, ~255 m below the land surface. The Ammonia Tanks, Rainier Mesa, Tiva Canyon, and Topopah Spring Tuffs consist mostly of unaltered, nonwelded to densely welded ash-flow tuff. The Calico Hills Formation consists of zeolitized bedded tuff. The Prow Pass Tuff consists of zeolitized, nonwelded to partially welded ash-flow tuff. Transmissive intervals in these wells must be inferred, because flow surveys were not conducted in either well. Gillespie et al. (1996) state that water production appears to originate primarily from fractures in the more densely welded parts of the Rainier Mesa and Topopah Spring Tuffs in water well 4. Because published lithologic descriptions for water wells 4 and 4a are vague, transmissive intervals in both wells were assumed to be the Rainier Mesa Tuff opposite perforated or slotted casing and all of the Topopah Spring Tuff. The total thickness of transmissive rock was estimated to be 109.1 m in water well 4 and 103.4 m in water well 4a. With water well 4a used as an observation well, a pumping test was conducted in water well 4 February 22–25, 1990 (K. Rehfeldt, HSI-Geotrans, 1999, written commun.). Pumping water well 4 for three days (4320 min) at an average rate of 36.3 L/s caused 5.12 m of drawdown in water well 4 and 0.50 m of drawdown in water well 4a. Typical of pumping tests in volcanic rocks in the area, 87% of the drawdown in the pumped well occurred within 10 min of starting the pump, and an estimated 59% of the drawdown in this well was caused by well losses. Recovery was

1

Early-time Match Point

DRAWDOWN, IN METERS

Late-time Match Point 0.1

Figure 52. Analysis of drawdown in UE-25 a#1 by the method of Neuman (1975), pumping test in UE-25 b#1, August 29 to September 1, 1981. (Data from Moench, 1984.)

0.01

DATA TYPE CURVE 0.001 1

10

100

1000

TIME SINCE PUMPING STARTED, IN MINUTES

10000

60

A.L. Geldon

not monitored continuously, but a measurement made at 10:00 on February 26 indicates that recovery in the pumped well was complete less than 20 hours after pumping stopped. Consistent with the water table being 70 m above the open interval in water well 4a and an observed relation between fracturing and water production at this site, drawdown in water well 4a was characteristic of a confined aquifer with fracture and matrix permeability. As shown in Figure 53, drawdown in water well 4a matched the type curve of Streltsova-Adams (1978) for η = 10 and r/B = 2.0. This analysis indicated transmissivity of 2100 m2/d, hydraulic conductivity of 20 m/d, matrix storativity of 0.002, and fracture storativity of 0.0002. Analytical results from this test, which apply to the Rainier Mesa and Topopah Spring Tuffs, are comparable to area-averaged values of transmissivity, hydraulic conductivity, and storativity obtained for the Yucca Mountain hydrologic domain, where water is transmitted mostly by the Crater Flat Group and Calico Hills Formation. This test demonstrates that the Topopah Spring Tuff is not inherently more permeable than typically less welded tuff of the Crater Flat Group and Calico Hills Formation, although many reports state otherwise (see, for example, Fridrich et al., 1994). Well Cluster ER-20-6, Western Pahute Mesa The Pahute Mesa hydrologic domain is bounded on the west, north, and, east by the margins of the Silent Canyon Cal-

dera complex and on the south by the northern rim of the Timber Mountain Caldera complex (Fig. 54). Pumping tests, considered in this study to be scientifically valid, were conducted in 9 boreholes on Pahute Mesa from May 1964 to September 1965 and in September 1988. Cross-hole airlift tests were conducted at the Knickerbocker nuclear test site in July and August 1966, and an 87-day cross-hole pumping test was conducted in the ER-20-6 well cluster from June to August 1997. Many of these tests were conducted in lava flows, whereas pumping tests at Yucca Mountain were conducted mostly in tuff, tuff breccia, and tuffaceous sedimentary rocks. Well cluster ER-20-6 was constructed in 1996 on Pahute Mesa, in the northwestern corner of the Nevada Test Site, 166–296 m southwest of emplacement hole U-20bd, in which the Bullion nuclear test was conducted (IT Corporation, 1998a). The well cluster was constructed to evaluate (1) the hydraulic and transport properties of the volcanic rocks in which the nuclear test was conducted; and (2) the extent of radionuclide migration from the Bullion explosion cavity. With ER-20-6#3 as the pumping and recovery well and ER-20-6#1 and ER-20-6#2 as injection and observation wells, pumping and tracer tests were conducted from June 2 to August 28, 1997. IT Corporation (1998b) analyzed the initial 6-hour hydrologic response in ER20-6#1 and ER-20-6#2 but ignored the remainder of the record. The 87-day record of drawdown in ER-20-6#1 was analyzed in this study and is discussed below.

DRAWDOWN, IN METERS

10

1

Figure 53. Analysis of drawdown in water well 4a by the method of StreltsovaAdams (1978), pumping test in water well 4, February 22–25, 1990. (Unpublished data from HSI-Geotrans, written communication, 1999.)

Match Point 0.1

DATA TYPE CURVE 0.01 1

10

100

1,000

TIME SINCE PUMPING STARTED, IN MINUTES

10,000

Implications for groundwater flow in the Southwest Nevada Volcanic Field Well cluster ER-20-6, at an altitude of 1971–1974 m AMSL, consists of three boreholes, ER-20-6#1, ER-20-6#2, and ER-206#3, that were drilled along an approximate radial from emplacement hole U-20bd, roughly parallel to locally predominant northeasterly striking fractures (IT Corporation 1997b, 1998a, 1998b). ER-20-6#1 is 131.4 m northeast of ER-20-6#3, and ER-20-6#2 is 89.1 m northeast of ER-20-6#3 (Fig. 55). Each of the holes was drilled to a depth of 975.4 m, but ER-20-6#1 and ER-20-6#2 were backfilled to a depth of ~898 m below land surface, and ER20-6#3 was backfilled to a depth of ~856 m below land surface. Each of the holes was telescoped downward, isolated from the surface and the saturated zone above the intended test interval with cement, and open in the intended test interval with slotted casing and well screen (Table 4). Figure 56 schematically shows the completion of well ER-20-6#1. None of the wells in the ER-20-6 cluster is open to the water table, which is ~616–618 m below the land surface at the site. The water table descends stratigraphically from the Rhyolite of

61

Delirium Canyon in ER-20-6#1 to the Calico Hills Formation in ER-20-6#3 as borehole locations change from the axis of a syncline to its southwestern limb (Fig. 57). Below the water table, formations present include the Rhyolite of Delirium Canyon, the Rhyolite of Echo Peak, and the Rhyolite of Silent Canyon, which consist of zeolitized bedded tuff, and the Calico Hills Formation, which consists mostly of rhyolite lava flows (IT Corporation, 1998a; Warren et al., 1998) Stony to glassy in the center, lava flows of the Calico Hills Formation grade to pumiceous lava and flow breccia at their tops, bottoms, and distal edges and are separated by intervals of zeolitized, bedded ash-fall tuff and nonwelded ash-flow tuff. Transmissive intervals in the ER-20-6 well cluster were identified on the basis of water production logs recorded as the wells were drilled (IT Corporation, 1998a). Seven discrete intervals in the Calico Hills Formation transmit water to ER20-6#2, and five discrete intervals in the Calico Hills Formation transmit water to ER-20-6#3. In ER-20-6#2, 26 m of zeolitized,

116°30′

PAHUTE MESA

Tr

Tr Tr

UE-20e-1

Tst Silent Canyon Caldera Complex

UE-19gs

Tst

Tmt

UE-19e

Tst

Tr Tr

Tst

UE-19c

UE-20f ER-20-6 well cluster

UE-20d/U-20d

Tr

UE-19i

UE-20a-2

PM-3

37°15′

Timber Mountain Caldera Complex UE-19fs

Tmt

Tr

Tr

0

Tqt

5

0

10 KILOMETERS 5 MILES

EXPLANATION TERTIARY VOLCANIC ROCKS Tr

RHYOLITIC LAVA FLOWS

Tst

VOLCANICS OF STONEWALL MOUNTAIN AND THIRSTY CANYON GROUP

Tmt

TIMBER MOUNTAIN GROUP

Tqt

COMENDITE OF QUARTET DOME AND TUNNEL FORMATION HIGH-ANGLE NORMAL FAULT – Ball on downthrown side CALDERA BOUNDARY – Hachures on topographic wall pointing inward; dashed where concealed and approximately located

UE-20f

BOREHOLE WITH HYDRAULIC-TEST DATA

Figure 54. Geologic map of Pahute Mesa, showing locations of boreholes used for hydraulic tests. (Modified from Workman et al., 2002.)

A.L. Geldon

bedded ash-fall tuff and nonwelded ash-flow tuff transmit 27% of the water, but in the open interval of the well, between depths of 764.4 and 897.6 m, all water is transmitted from 62.8 m of rhyolite lava flows (Fig. 58). The same transmissive thickness is assumed for the open interval of ER-20-6#1, which is near ER20-6#2 but did not have a production log available. In ER-206#3, all water is produced from rhyolite lava flows. About 50% of this production is from the pumiceous tops and bottoms of these flows. In the open interval of ER-20-6#3, between depths of 765.4 and 855.6 m, all water is transmitted from 41.6 m of rhyolite lava flows. Pumping in ER-20-6#3 to establish a steep, quasi-steadystate hydraulic gradient for tracer tests in the Calico Hills Formation at the ER-20-6 well cluster began at 12:04 on June 2, 1997 and continued until 14:45 on August 28, 1997 (IT Corporation, 1998b). Discharge from ER-20-6#3 averaged 7.32 L/s during the 87.1 days that the pump was in operation. Operating the pump outside of its optimal performance range required repeated adjustment of the pump speed to keep the pumping rate within its target range. The pump shut off 19 times because of problems with the generators supplying power to the pump. These shutoffs lasted 5–420 min and caused water levels in ER-20-6#3 to recover 44%–96% while the pump was off. Tracer-test operations had no effect on water levels in ER-20-6#3. Pumping from ER-20-6#3, as in other hydraulic tests discussed in this report, caused rapid drawdown and recovery in the pumped well and much less drawdown in observation wells (IT Corporation, 1998b). Drawdown in ER-20-6#3 reached ~11 m less than 30 min after pumping started, oscillated between 8 and 14 m during the first 10 days of pumping, and then decreased to ~7 m during the remainder of the pumping. Within 9 h of shutting off the pump, the water level in ER-20-6#3 had recovered to 94% of its pre-pumping value. In contrast to the pumping well, drawdown in ER-20-6#2 reached 1.61 m, and drawdown in ER-20-6#1 reached 1.44 m by the end of pumping. Pumping intermittently at rates of ~0.3 L/s to inject tracers into ER-20-6#1 and ER-20-6#2 negligibly disturbed water levels in the injection wells (IT Corporation, 1998b). Drawdown in ER-20-6#1 between 0.0031 and 87 days (4.5–125,280 min) after pumping started, which was not affected by pump shutoffs, tracer injections, or pumping in the injection wells, was analyzed by the method of Streltsova-Adams (1978) for a confined aquifer with fracture and matrix permeability. Data were matched to the type curve for η = 10 and r/B = 0.5 adequately, despite three different wells pumping at different times and partial recovery during numerous pump shutoffs (Fig. 59). This analysis indicated transmissivity of 200 m2/d, fracture hydraulic conductivity of 3.2 m/d, fracture storativity of 0.0007, and matrix storativity of 0.006. In comparison, IT Corporation (1998b) analyzed 6 h of drawdown in well ER-206#2 in the same test by the method of Theis (1935) and obtained transmissivity of 150 m2/d, hydraulic conductivity of 2.4 m/d, and storativity of 0.0003. Values of hydraulic conductivity and storativity from both observation wells are consistent with each

ER-20-6#1 4123690 46.1 m 4123670 ER-20-6#2

UTM NORTH (METERS)

62

4123650 89.1 m 4123630

131.4 m

4123610

4123590 ER-20-6#3 4123570 551270

551290

551310

551330

551350

551370

551390

UTM EAST (METERS)

Figure 55. Surface locations of ER-20-6 wells, Bullion site, Pahute Mesa. (Coordinates from IT Corporation, 1998a.)

Figure 56. Completion of borehole ER-20-6#1 (IT Corporation, 1998a).

Implications for groundwater flow in the Southwest Nevada Volcanic Field

63

Figure 57. Geologic section through the ER-20-6 well cluster, Pahute Mesa. (Modified from IT Corporation, 1998a.)

other and with values of these hydraulic properties obtained from previously discussed pumping tests of tuff at Yucca Mountain and in Frenchman Flat. Knickerbocker Site, Western Pahute Mesa Although numerous hydraulic tests were done to support 85 underground nuclear tests conducted beneath Pahute Mesa from 1965 to 1991 (Laczniak et al., 1996), cross-hole hydraulic tests are known to have been done at only one location, the Knickerbocker nuclear test site. Drilling of the emplacement hole for the Knickerbocker nuclear test, U-20d, was stopped twice to conduct a series of hydraulic tests (USGS unpublished data, available through the GSA Data Repository1). A pumping test in UE-20d reported by Blankennagel and Weir (1973) was 1

GSA Data Repository Item 2004150, U-20d airlift and pumping tests, is available on request from Documents Secretary, GSA, P.O. Box 9140, Boulder, CO 80301-9140, USA, [email protected], or at www.geosociety.org/pubs/ ft2004.htm.

attempted, but it was disrupted by concurrent drilling of, and discharge from, U-20d and could not be analyzed convincingly. In five of the tests, water was airlifted or pumped from U-20d, and the water level response in UE-20d, 25.9 m to the south, was recorded. These five hydraulic tests were analyzed in this study and are discussed below. Results of two tests are included in Appendix B. Exploration hole UE-20d, at a surface altitude of 1906 m AMSL, was drilled in 1964 to a depth of 1369.2 m (Thordarson et al., 1967; Orkild and Jenkins 1978). The hole was telescoped downward and cased to a depth of 745.5 m (Table 4), ~113 m below the water table. From the bottom of casing to the bottom of the hole (745.5–1369.2 m), UE-20d was open in the Rhyolite of Benham, Tiva Canyon Tuff, and Topopah Spring Tuff of the Paintbrush Group and in the Calico Hills Formation (Orkild and Jenkins 1978; Warren et al., 1998). The Paintbrush Group at the Knickerbocker site consists of nonwelded to densely welded ash-flow tuff and zeolitized, bedded tuff, tuffaceous sandstone, and siltstone. The Calico

A.L. Geldon

Hills Formation at this site consists of zeolitized, bedded and nonwelded tuff overlying rhyolite lava flows. Drilling of U-20d, a large-diameter emplacement hole, began in 1966 at the same altitude and in the same geologic units as UE-20d. Drilling of U-20d was stopped July 25–28, 1966, with casing advanced to a depth of 632 m and the hole at a depth of 919.3 m, to conduct hydraulic tests in the Tiva Canyon Tuff. The test interval, between depths of 745.5 and 919.3 m, extended from the bottom of casing in UE-20d to the bottom of U-20d. Slug-injection tests reported by Blankennagel et al. (1964) were interpreted to indicate that all water in the test interval was transmitted by 46.3 m of moderately to densely welded tuff, which in UE-20d, occurred between depths of 785.8 and 832.1 m. Water was airlifted from U-20d on July 26, 1966, from 00:50 to 10:32, a period of 582 min. Discharge, which was monitored by a flume, averaged 9.46 L/s and caused 1.36 m of drawdown in UE-20d. By 13:30, 178 min after airlifting ended, residual drawdown in UE-20d was 0.29 m, and recovery was 1.25 m (92% of the pre-test water level). Consistent with the test interval being well below the water table, recovery data were analyzed by the method of Streltsova-Adams (1978) for a confined aquifer with fracture and matrix permeability. Data from 6 to 178 min after airlifting ended were matched adequately to the type curve for η = 10 and r/B = 0.5 (Fig. 60). This analysis indicated transmissivity of 110 m2/d, fracture hydraulic conductivity of 2.4 m/d, fracture storativity of 0.001, and matrix storativity of 0.01. With drilling of U-20d stopped at depths of 1184–1195 m, three airlift tests and one pumping test using UE-20d as an observation well were conducted August 10–12, 1966 (Fig. 61). As before, the test interval extended from the bottom of casing in UE-20d to the bottom of U-20d. The top of the test interval was 745.5 m and, depending on the test, the bottom of the interval was between 1184 and 1195 m. At the new depth of U-20d, the Topopah Spring Tuff and the Calico Hills Formation above the top of rhyolite lava flows in the formation were included with the Tiva Canyon Tuff in the test interval. Slug tests reported by Blankennagel et al. (1964) indicated that rhyolite lava flows in the Calico Hills Formation below the test interval are transmissive, but water-level changes in UE-20d during the second series of tests did not indicate upward leakage from these lava flows. Hence, the thickness of transmissive rock apparently did not change from 46.3 m as the length of the test interval increased from the first to the second series of tests. Airlift test 2, which is representative of the second series of tests, was conducted on August 11, 1966, from 05:00 to 10:38, a period of 338 min. Discharge from U-20d at an average rate of 8.71 L/s caused 1.44 m of drawdown in UE-20d. By 12:39, 121 min after airlifting ended, recovery in UE-20d was complete. Residual drawdown data from 4 to 121 min after airlifting stopped were fit to a straight line with a slope of 0.988 m per log cycle of time (Fig. 62). Analysis of the residual drawdown data by the method of Theis (1935) indicated transmissivity of 140 m2/d and hydraulic conductivity of 3.0 m/d.

600 Static Water Level

Rhyolites of Delirium Canyon, Echo Peak & Silent Canyon-Zeolitized Bedded Tuff 640

Calico Hills Formation

Zeolitized Bedded Tuff Rhyolite Flow Breccia

680

Zeolitized, Nonwelded Ash-flow Tuff

720

DEPTH, IN METERS

64

760

Pumiceous Rhyolite Lava Flow

800

840

880 Rhyolite Lava Flow 920 Pumiceous Rhyolite Lava and Flow Breccia 960

TOTAL TRANSMISSIVE THICKNESS=102 METERS

Zeolitized, Bedded Ash-fall Tuff and Nonwelded Ash-flow Tuff

1000 0

10

20

30

40

50

60

70

80

90

100

FLOW, IN PERCENT

Figure 58. Production log for ER-20-6#2 recorded as the well was drilled on Pahute Mesa in March 1996. Although rhyolite lava flows produced most of the water, 33% of the water produced by this well is from zeolitized bedded tuff, nonwelded ash-flow tuff, and tuff breccia (Production data and geologic information from IT Corporation, 1998a).

Analyses of airlift tests at the Knickerbocker site indicate that welded ash-flow tuff there appears to be as permeable as rhyolite lava flows at the site of the ER-20-6 well cluster. These tests raise the possibility that the long-held perception that lava flows are a better source of water than tuff beneath Pahute Mesa might be the result of preferential drilling of wells in rhyolitic lava flows. DISTRIBUTION OF HYDRAULIC CONDUCTIVITY In this part of the report, the effects of structure and stratigraphy on the distribution of hydraulic conductivity in the eastern Southwest Nevada Volcanic Field are evaluated. Hydraulic conductivity values used in this part of the study were determined directly from cross-hole hydraulic tests or extrapolated from single-well hydraulic tests to cross-hole scale using Equation 23 to prevent scale effects from influencing interpretations. It is recognized that the accumulation of more data in future years might prove hydraulic conductivity values derived from Equation 23 to be inaccurate. It is recognized, also, that spatial distributions of hydraulic conductivity shown in this part of the report are based partly on the author’s interpretations of factors that affect groundwater flow in the study area and, therefore, are

Implications for groundwater flow in the Southwest Nevada Volcanic Field

65

10

1

DRAWDOWN, IN METERS

Match Point

Figure 59. Analysis by the method of Streltsova-Adams (1978) of drawdown in ER-20-6#1, pumping test in ER-20-6#3, Pahute Mesa, June 2–August 28, 1997. (Data from IT Corporation, 1998b.)

0.1

0.01

DATA TYPE CURVE 0.001 0.001

0.01

0.1

1

10

100

TIME SINCE PUMPING STARTED, IN DAYS

RECOVERY, IN METERS

10

Figure 60. Analysis of recovery in UE20d by the method of Streltsova-Adams (1978), airlift test 1 in U-20d, Pahute Mesa, July 26, 1966. (Data from U.S. Geological Survey files.)

1

Match Point

DATA TYPE CURVE 0.1 1

10

100

TIME SINCE AIRLIFTING ENDED, IN MINUTES

1000

DEPTH TO WATER BELOW MEASURING POINT, IN METERS

66

A.L. Geldon

631

Airlift Test 2

Airlift Test 3

Pumping Test 1

Airlift Test 4

632

633

Figure 61. Hydrologic response of UE20d to discharge from U-20d, August 11–12, 1966. (Data from U.S. Geological Survey files.)

634

635

636 0

400

800

1,200

1,600

2,000

2,400

TIME SINCE WITHDRAWAL STARTED, IN MINUTES

0.0

RESIDUAL DRAWDOWN, IN METERS

0.2

0.4

0.6

Figure 62. Analysis of residual drawdown in UE-20d by the method of Theis (1935), airlift test 2 in U-20d, August 11, 1966. (Data from U.S. Geological Survey files.)

0.8 s = 0.988 x Log (t/t') - 0.570 R2 = 0.99

1.0

1.2

1.4

1.6 1

10 TIME SINCE AIRLIFTING STARTED/TIME SINCE AIRLIFTING STOP

100

Implications for groundwater flow in the Southwest Nevada Volcanic Field non-unique. However, computer software does not exist at the date of this writing that can contour hydraulic properties while accounting for non-mathematical aspects of geology that influence distributions of hydraulic properties.

67

to the Solitario Canyon, Pagany Wash, Sever Wash, Paintbrush Canyon, and Busted Butte Faults (the latter is interpreted in this report to be a section of the “Fortymile Wash Fault”). Hydraulic Conductivity Distribution at Pahute Mesa

Relation of Lithology to Hydraulic Conductivity Four lithologic categories were distinguished from available data to evaluate the influence of lithology on hydraulic conductivity: (1) nonwelded to densely welded ash-flow tuff, (2) bedded tuff, tuffaceous sedimentary rocks, and ash-flow tuff, (3) tuff breccia and tuff; and (4) silicic to intermediate lava flows. Zeolitic to argillic alteration of tuffaceous rocks as an influence on hydraulic conductivity was evaluated, also. The inclusion of tuff with tuff breccia and the inclusion of ashflow tuff with bedded tuff and tuffaceous sedimentary rocks were unavoidable because of limitations in available data. Tuff breccia generally is so fractured and poorly indurated that it probably controls the hydraulic conductivity of intervals where ash-flow tuff or bedded tuff is intercalated. Bedded tuff and tuffaceous sedimentary rocks generally are so zeolitized or argillized that they probably control the hydraulic conductivity of intervals where ash-flow tuff is intercalated. Despite some ambiguity in the data, it appears that ash-flow tuff might be slightly more permeable than silicic to intermediate lava flows, and that zeolitic to argillic alteration decreases the permeability of tuffaceous rocks (Table 12 and Fig. 63). Hydraulic Conductivity Distribution at Yucca Mountain At Yucca Mountain, the distribution of hydraulic conductivity is independent of formations that comprise the Younger Tertiary tuff and lava flows HSU, but faults appear to be associated spatially with trends in the data (Fig. 64). Increased hydraulic conductivity appears to be related to the Midway Valley, Bow Ridge, and Ghost Dance Faults, and the area where the Midway Valley, Bow Ridge, Dune Wash, and East Ridge Faults terminate in close proximity. Decreased hydraulic conductivity appears to be related

Somewhat dependent on the distribution of geologic formations, hydraulic conductivity decreases toward the lateral center and the west side of Pahute Mesa (Fig. 65). Whereas all areas of the mesa with large hydraulic conductivity are associated with formations that transmit water from rhyolite or comendite lava flows, some areas with relatively small hydraulic conductivity, also, can be associated with rhyolite or comendite lava flows. Areas with relatively small hydraulic conductivity in the western part of Pahute Mesa invariably are associated with formations that transmit water from intervals of tuffaceous rocks or tuff intercalated with rhyolite or comendite lava flows. Trends in the data appear to be independent of the numerous northerly striking faults that transect the mesa. However, hydraulic conductivity clearly increases toward the southern and eastern margins of the Silent Canyon Caldera complex. This relationship was extrapolated to indicate increased hydraulic conductivity toward the northern margin of the Silent Canyon Caldera complex, also. Topographic expression of the northern, eastern, and southern margins of the Silent Canyon Caldera complex indicates collapse of blocks into the calderas, which probably caused extensive fracturing of rock in the collapsed blocks. Fracturing of this origin would explain the increased hydraulic conductivity that appears to be associated with the margins of the caldera complex. SUMMARY AND CONCLUSIONS Yucca Mountain, ~150 km northwest of Las Vegas, Nevada, has been chosen by the United States government to be the site of the nation’s first permanent repository for high-level nuclear waste. About 25 km north of Yucca Mountain, Pahute Mesa was the site of 85 underground nuclear tests from 1966 to 1991. Yucca Mountain, Pahute Mesa, and adjacent areas of the Nevada Test

TABLE 12. RELATION OF HYDRAULIC CONDUCTIVITY TO LITHOLOGY IN THE YOUNGER TERTIARY TUFF AND LAVA FLOWS HYDROSTRATIGRAPHIC UNIT Lithology

Silicic to intermediate lava flows Nonwelded to densely welded ash-flow tuff Bedded tuff and tuffaceous sedimentary rocks and ash-flow tuff Tuff breccia and tuff Unaltered tuffaceous rocks Zeolitized to argillized tuffaceous rocks

Number of observations

Hydraulic conductivity, in meters per day Minimum

Maximum

–1 Standard Deviation (16% ≤)

Log mean (50% ≤)

+1 Standard Deviation (84% ≤)

12 55 5

0.60 0.095 0.12

20 74 8.5

1.3 1.7

4.2 6.1 Insufficient data

14 22

5 26 11

4.4 0.095 0.82

28 74 8.5

1.3 1.5

Insufficient data 6.4 3.2

31 7.0

68

A.L. Geldon

Site form most of the eastern third of the Southwest Nevada Volcanic Field. The hydrogeology of the Southwest Nevada Volcanic Field is the focus of this report. The Southwest Nevada Volcanic Field is situated in the Death Valley region of the Great Basin, in southeastern Nevada and California. The terrain consists of northerly and northwesterly trending mountain ranges surrounded by broad, sediment-filled basins. More than 11,000 m of faulted Mesozoic, Paleozoic, and Late to Middle Proterozoic sedimentary rocks underlie Tertiary volcanic rocks throughout much of the Death Valley region. The Southwest Nevada Volcanic Field comprises 17 extensive ash-flow tuff sheets and associated lava flows that erupted from at least seven large, overlapping caldera complexes from 15 million to 7 million years ago. Pahute Mesa, at the center of the Silent Canyon and Timber Mountain Caldera Complexes, is underlain by more than 4170 m of rhyolite, rhyodacite, and trachyte lava flows intercalated with tuff. Yucca Mountain, on the apron of these caldera complexes, is underlain by variably welded and fractured ash-flow tuff, intercalated with bedded ash-fall and reworked tuff, volcaniclastic rocks, tuff breccia, and minor dacite and andesite lava flows. Alteration of tuff to zeolite and clay minerals is common at eruptive centers north of Yucca Mountain, but it decreases in intensity toward the southern part of Yucca Mountain. Yucca Mountain and Pahute Mesa are located at the southern terminus of a series of interconnected hydrographic basins that comprise the Great Basin regional aquifer system. Yucca Mountain is in the Alkali Flat–Furnace Creek groundwater basin, which is bordered on the north and west by the Pahute Mesa–Oasis Valley groundwater basin and on the east by the

Ash Meadows groundwater basin. In deep structural basins, such as the Amargosa Desert, groundwater flows profusely through basin-fill sediments. Deep interbasin flow occurs primarily through fractured Paleozoic carbonate rocks. At Yucca Mountain and Pahute Mesa, rhyolitic to rhyodacitic lava flows, ash-flow tuff, bedded tuff, and tuff breccia can be very transmissive. Groundwater recharged in highlands, such as Pahute Mesa, Timber Mountain, and Shoshone Mountain, generally flows southward and discharges at Oasis Valley, Ash Meadows, Alkali Flat, and Death Valley. Stratabound aquifers and aquitards have long been the basis for discussions and numerical simulations of groundwater flow in the Death Valley region. However, this categorization fails to account for structurally and lithologically controlled variations in hydraulic properties within geologic units and vertical groundwater flow between geologic units of diverse lithology, which limit regional persistence of aquifers and aquitards. Eleven hydrostratigraphic units (HSUs) were recognized in this study for the purpose of discussing hydraulic properties. Miocene and Pliocene volcanic rocks are designated herein as the “Younger Tertiary tuff and lava flows HSU.” This HSU at Yucca Mountain extends downward from the Rainier Mesa Tuff in the Timber Mountain Group to the Lithic Ridge Tuff in the Tram Ridge Group. This HSU at Pahute Mesa extends downward from the Volcanics of Stonewall Mountain to the Comendite of Split Ridge in the Belted Range Group. This HSU is nearly as permeable as Paleozoic carbonate rocks and QuaternaryTertiary basin-fill sediments and more permeable than all other HSUs in the study area.

CUMULATIVE PERCENT EQUAL OR LESS THAN

100 90 +1 STANDARD DEVIATION

80

LAVA FLOWS

70

ASH-FLOW TUFF

60

ZEOLITIZED AND ARGILLIZED TUFF GEOMETRIC MEAN

50

Figure 63. Relation of cross-hole-scale hydraulic conductivity to lithology in the Younger Tertiary tuff and lava flows hydrostratigraphic unit.

40 30 20

-1 STANDARD DEVIATION

10 0 0.1

1

10

HYDRAULIC CONDUCTIVITY, IN METERS PER DAY

100

Implications for groundwater flow in the Southwest Nevada Volcanic Field

EXPLANATION

5

Quaternary deposits Miocene volcanic rocks Exploratory Studies Facility Line of equal hydraulic conductivity–Interval, 5 meters per day Block-bounding fault Strike-slip fault Relay structure Dominant intrablock fault

15

Borehole, with hydraulic conductivity, in meters per day

Figure 64. Hydraulic conductivity distribution at Yucca Mountain.

69

70

A.L. Geldon

Transmissive intervals in the Younger Tertiary tuff and lava flows HSU are bound not by stratigraphic or lithologic contacts but by terminations of vertically continuous fractures zones or, less commonly, zones with relatively large matrix permeability. Transmissive intervals typically have dual fracture and matrix permeability. Within transmissive intervals, there is no correlation between the intensity of fracturing or the degree to which tuff layers are welded. In cross-hole hydraulic tests, the effective aquifer is the total thickness of transmissive intervals in the volume of rock between the production and observation wells. The upper and lower limits of the effective aquifer change depending on the interval that is open in the production well. Diverse rock types and fracture frequency, among other factors, impart layered heterogeneity to the Younger Tertiary tuff and lava flows HSU. HSU boundaries

are irrelevant for determining hydraulic conductivity, because hydraulic tests can be conducted in multiple combinations of variably transmissive intervals at any site within this HSU. For example, six cross-hole pumping tests conducted from May 1984 to June 1998 at the C-holes complex, on the east flank of Yucca Mountain, indicated a range in hydraulic conductivity of 0.12–40 m/d and a range in storativity of 0.00001–0.003 for six intervals within the Calico Hills Formation and the Prow Pass, Bullfrog, and Tram Tuffs. The extent to which transmissive intervals can be traced laterally largely depends on the length, spacing, and interconnectivity of fractures. Tracer tests done at Pahute Mesa in June 1997 established that transmissive intervals in rhyolite lava flows within the Calico Hills Formation locally are continuous laterally for 89–131 m. Tracer tests and cross-hole seismic tomography

Figure 65. Hydraulic conductivity distribution at Pahute Mesa.

Implications for groundwater flow in the Southwest Nevada Volcanic Field done at Yucca Mountain between 1989 and 1997 established that transmissive intervals in the Bullfrog and Tram Tuffs locally are continuous laterally for 29–85 m. Regional groundwater flow between transmissive intervals is maintained by downward or upward hydraulic gradients enhanced by fracture networks related to regional structural fabrics. The principal structures affecting the Yucca Mountain area are a series of high-angle, north-northeasterly striking faults, including the Solitario Canyon, Bow Ridge, Midway Valley, Paintbrush Canyon, and Fortymile Wash Faults. Most fractures encountered in outcrops and boreholes at Yucca Mountain are aligned with these faults. Of secondary importance are northwesterly trending faults associated with the Walker Lane Belt, including the Highway 95, Drillhole Wash, Pagany Wash, and Sever Wash Faults, which have imposed an overprint on fracture frequency in Yucca Mountain boreholes. The coexistence of north-northeasterly and northwesterly striking faults and related fractures in the Yucca Mountain area imparts lateral (x-y) heterogeneity to the area. An example of this heterogeneity in a 21 km2 area was demonstrated by a pumping test in borehole UE-25 c#3 at Yucca Mountain, which was conducted from May 22 to June 1, 1995. Four observation wells, 29–2245 m from UE-25 c#3, exhibited drawdown of 0.072–0.42 m that was distributed along north-northeasterly and northwesterly trending axes. Drawdown in boreholes UE25 c#2, UE-25 ONC-1, and USW H-4 decreased as a function of distance in a northwesterly direction. The Antler Wash Fault Zone, in which boreholes UE-25 c#2, UE-25 ONC-1, and USW H-4 are present, is believed to have influenced drawdown in these observation wells. Drawdown in UE-25 c#1, north-northeast of, and about three times farther from the pumping well than UE-25 c#2, exhibited drawdown that was 26% larger than that in UE25 c#2. UE-25 c#1 might have been far enough from the Antler Wash Fault Zone that the Midway Valley Fault, which intersects UE-25 c#1, was the principal influence on drawdown in this well. Plotted as a function of time, drawdown in UE-25 c#2, UE-25 ONC-1, and USW H-4 indicated horizontal hydraulic conductivity of 14 m/d in a northwesterly direction, whereas recovery in UE-25 c#1 indicated horizontal hydraulic conductivity of 7 m/d in a north-northeasterly direction. Faults can act as either conduits or barriers to regional groundwater flow. A recharging fault conducts water between transmissive intervals on either side that have been brought into proximity by displacement of confining layers. The most prominent fault conduit in the Yucca Mountain area is the Midway Valley Fault, a high-angle, normal fault with down-to-the-west displacement. A pumping test in UE-25 c#3 conducted from October 30 to November 15, 1984, induced recharge from the Midway Valley Fault to the Tram Tuff in UE-25 c#1. Another pumping test in UE-25 c#3 conducted from May 8, 1996, to November 12, 1997, produced quasi–steady-state drawdown in two observation wells ~2250 m from UE-25 c#3, USW H-4, and UE-25 WT#14, after 72,000 min of pumping. An image-well solution indicated that recharge from the Midway Valley Fault

71

2713 m northeast of UE-25 c#3 inhibited drawdown in USW H4 and UE-25 WT#14 during this test. Analyses of drawdown in USW H-4 and UE-25 WT#14 prior to the appearance of boundary effects indicated transmissivity of 560–710 m2/d, hydraulic conductivity of 4.2–5.0 m/d, and storativity of 0.002. Faults act as barriers to regional groundwater flow where transmissive intervals are offset against non-transmissive intervals. Primarily, barrier-boundary faults segment the Alkali Flat–Furnace Creek and Ash Meadows groundwater basins into separate hydrologic domains. The pumping test in UE-25 c#3 conducted from May 8, 1996, to November 12, 1997, involved 22 observation wells. This test progressed for 553 days, long enough to establish that the non-responding wells are beyond the boundaries of the Yucca Mountain hydrologic domain. Lines demarcating responding and non-responding observation wells coincided with the Solitario Canyon, Sever Wash, Pagany Wash, Yucca Wash, and Fortymile Wash Faults, which appear to bound the northern part of the Yucca Mountain hydrologic domain. Geophysical data and steepened gradients in the potentiometric surface indicate that the Fortymile Wash, Highway 95, and Southern Windy Wash Faults bound the southern part of the Yucca Mountain hydrologic domain. North of the Yucca Mountain hydrologic domain, northnortheasterly trending, high-angle, extensional faults and the structural walls of overlapping caldera complexes disturb regional groundwater flow. The north-northeasterly trending, high-angle faults can act as either barriers or conduits, depending on how they offset transmissive and non-transmissive volcanic rocks. Different sequences of lava flows and tuff emplaced within individual calderas and faults associated with caldera walls impede groundwater flow. The Ammonia Tanks and Rainier Mesa calderas probably cause limited hydraulic connection between Pahute Mesa and areas to the south. Despite the complexity of the groundwater system in the eastern Southwest Nevada Volcanic Field, extensive hydraulic testing has been done there successfully for nearly 50 years. Hydraulic testing in the area evolved over the years from window-of-opportunity efforts during drilling of exploration, monitoring, and emplacement boreholes for nuclear tests to systematic, multidisciplinary approaches in boreholes dedicated for hydrologic research. Planning of the later tests benefited from the knowledge of what worked and what did not in the earlier tests. In the early days, slug-injection and swabbing recovery tests were considered more useful than pumping tests, which tended to be short (1–2 days) and crudely designed. With an understanding that the length of a test can influence the shape of the drawdown curve and, hence, the determination of hydraulic properties, 1–2 weeks commonly is allowed in modern pumping tests for full development of the drawdown curve. Hydraulic-test data for the Younger Tertiary tuff and lava flows HSU were obtained from 41 sites in the eastern Southwest Nevada Volcanic Field for this study. This database includes 40 published hydraulic-test results and 46 revised or new analyses of hydraulic tests.

72

A.L. Geldon

Analyzing hydraulic tests rarely is straightforward because of complicating factors, which were considered wherever possible. Boreholes completed in volcanic rocks in the study area typically are open in both transmissive and non-transmissive intervals. Several types of borehole flow surveys were used to identify the total thickness of transmissive rock in test intervals. A variety of techniques was used in support of, or in lieu of flow surveys to identify transmissive intervals. These techniques included: (1) drilling production logs; (2) relative specific capacity profiles determined from slug-injection and swabbingrecovery tests; (3) temperature logs; (4) resistivity logs, used with temperature, acoustic televiewer, television, and caliper logs; and (5) lithologic logs, used together with other indicators or alone. Specific methods used to identify transmissive intervals in individual boreholes depended on the funding and the understanding of the efficacy of different methods available at the time that hydraulic tests were conducted in them. All methods indicated that transmissive intervals typically represent a small proportion of the open length of a borehole. Earth tides and atmospheric-pressure change superimpose synchronous water-level changes in wells that are opposite in sense and less than the full magnitude of the atmospheric-pressure change. In a production well, these superimposed water-level changes generally are much smaller than water-level changes caused by the test and can be ignored. In observation wells near the pumping well, it was found that removing the effects of Earth tides and atmospheric-pressure change was advantageous but not always necessary. In observation wells more than several hundred meters from the production well, Earth tides and atmospheric-pressure change inevitably obscured responses to pumping and injection and were removed to detect these responses if a barometer record was available. An omnipresent feature of hydraulic tests at Yucca Mountain, Pahute Mesa, and in adjacent areas is the tendency for most of the drawdown and recovery to occur very rapidly, especially in the pumping well. In many pumped wells, 80%–90% of the drawdown and recovery occurs within 10 minutes of starting or stopping the pump. These rapid water-level changes generally are attributable to draining of water stored in the well (commonly termed “borehole storage”) and well losses—head lost from: (1) water turbulently entering the well from the aquifer; (2) inefficient placement of the pump, openings, and other well-design features; and (3) drilling-caused damage to the aquifer near the well. Forty-four to eighty-three percent of drawdown in the pumping well in cross-hole tests was estimated in this study to be attributable to well losses. Because of the way that drawdown and recovery in pumping tests conducted in the study area depart from the ideal, it was found that some conventional analytical methods could not be used or had to be used with caution. Estimates of transmissivity from specific capacity typically are way too large, because the equation used to estimate transmissivity from specific capacity (Lohman, 1979) assumes that drawdown is spread out over the length of the test, instead of being concentrated within the initial part of the test.

In tests with rapid recovery, the Theis (1935) recovery method also fails, because the analysis tends to be weighted toward very small water-level changes near the end of the recovery period. Because drawdown and recovery when plotted as a function of log time tend to be multi-segmented, the analytical method of Cooper and Jacob (1946), which requires fitting a straight line to one segment, often results in arbitrary and incorrect choices. The Theis (1935) recovery method and the method of Cooper and Jacob (1946), both, tend to overestimate transmissivity. Values of hydraulic conductivity and transmissivity are dependent on the scale of the tests conducted to obtain these properties. Hydraulic conductivity and transmissivity values obtained from drawdown in a pumped well are comparable to hydraulic conductivity and transmissivity values obtained from slug-injection, swabbing-recovery, and bailing-recovery tests, but they are much smaller than hydraulic conductivity and transmissivity values obtained from observation-well data. Analyses of pumping well data are unreliable indicators of hydraulic properties. Because cross-hole pumping, airlift, and injection tests have been conducted in the Younger Tertiary tuff and lava flows HSU at only five sites in the study area, one cannot make any reasonable interpretations about hydraulic-conductivity distribution in this HSU without finding a way to convert hydraulic conductivity values obtained from single-well tests throughout the study area to cross-hole scale. A scaling equation was developed from (1) seven paired analyses of pumping well and observation well data from six pumping tests in four wells, and (2) three paired analyses of data obtained from tests conducted at different scales in three intervals of borehole UE-25 c#1. It is recognized that the accumulation of more data from cross-hole tests in future years might prove hydraulic conductivity values derived from this equation to be inaccurate. The determination of hydraulic properties from cross-hole, constant-rate, pumping, and airlift tests conducted at Yucca Mountain, Pahute Mesa, and Frenchman Flat was discussed to document the best analyses for the study area. Summary results of all hydraulic tests used to prepare this report are appended to the report. A pumping test conducted at the C-holes complex from May 22 to June 1, 1995, indicated that the Calico Hills Formation and the Prow Pass, Bullfrog, and Tram Tuffs, together, at this site have composite transmissivity of 1800–2100 m2/d, horizontal hydraulic conductivity of 7.3–13 m/d, storativity of 0.001–0.003, and a specific yield of 0.01–0.2. Duplicating heterogeneity at the scale of the Yucca Mountain hydrologic domain, hydraulic conductivity and storativity at the C-holes complex are larger in a northwesterly direction than in a north-northeasterly direction. A pumping test conducted in the lower Bullfrog interval of UE-25 c#3 from May 8, 1996 to November 12, 1997, caused drawdown in 11 observation wells 29–6414 m from the pumping well. Drawdown over the 81 km2 area affected by pumping ranged from 0.14 to 0.47 m in observation wells after 553 days. This drawdown was influenced mainly by the north-northeasterly trending Solitario Canyon, Bow Ridge, Midway Valley,

Implications for groundwater flow in the Southwest Nevada Volcanic Field Paintbrush Canyon, and Fortymile Wash Faults, but the northwesterly trending Drill Hole Wash, Sever Wash, and Pagany Wash Faults influenced drawdown in the northern part of the area affected by the test. This test showed that: (1) water-level disturbances from periodic tracer tests and unplanned pump shutoffs were ephemeral with respect to long-term trends in drawdown and could be ignored in analyzing the long-term drawdown; (2) the spreading cone of depression encompassed less transmissive rock as the test progressed; (3) formations above and below the test interval in different structural blocks were brought into the cone of depression after thousands of minutes of pumping; (4) hydraulic conductivity in the lower Bullfrog Tuff at the C-holes complex was 40 m/d in a westnorthwesterly direction, parallel to the Antler Wash Fault zone, and 20 m/d in a north-northeasterly direction, parallel to the Midway Valley Fault; and (5) the Younger Tertiary tuff and lava flows HSU in the northern part of the Yucca Mountain hydrologic domain possessed area-averaged transmissivity of 2200–2400 m2/d, hydraulic conductivity of 22–24 m/d, and storativity of 0.0006–0.002. A cross-hole pumping test conducted February 22–25, 1990, in Frenchman Flat duplicated area-averaged hydraulic properties of the Younger Tertiary tuff and lava flows HSU at Yucca Mountain. Pumping water well 4 in this test produced 0.50 m of drawdown in water well 4a, 371 m to the southwest. Analysis of this drawdown indicated transmissivity of 2100 m2/d, hydraulic conductivity of 20 m/d, fracture storativity of 0.0002, and matrix storativity of 0.002. Three other cross-hole hydraulic tests discussed in this report, that were conducted in diverse hydrogeologic settings, produced values of hydraulic properties which were comparable to each other but smaller than those indicated by tests at the C-holes complex. Pumping borehole UE-25 b#1 in Drill Hole Wash at Yucca Mountain from August 29 to September 1, 1981, produced 0.64 m of drawdown in borehole UE-25 a#1, 106.8 m to the south-southwest. Analysis of this drawdown indicated that faulted Calico Hills Formation, Prow Pass Tuff, and Bullfrog Tuff in the area of the test have composite transmissivity of 350 m2/d, horizontal hydraulic conductivity of 7.8 m/d, vertical hydraulic conductivity of 0.8 m/d, storativity of 0.0009, and a specific yield of 0.07. Airlifting water from borehole U-20d on Pahute Mesa in July and August 1966 produced 1.36–1.44 m of drawdown in borehole UE-20d, 25.9 m to the south. Analysis of this drawdown indicated that moderately to densely welded Tiva Canyon Tuff at the Knickerbocker nuclear test site has transmissivity of 110–140 m2/d, horizontal hydraulic conductivity of 2.4–3.0 m/d, fracture storativity of 0.001, and matrix storativity of 0.01. Pumping water from borehole ER-20-6#3 on Pahute Mesa from June 2 to August 28, 1997, produced 1.44 m of drawdown in borehole ER-20-6#1, 131.4 m to the northeast. Analysis of this drawdown indicated that rhyolite lava flows in the Calico Hills Formation at the Bullion nuclear test site have transmissivity of 200 m2/d, horizontal hydraulic conductivity of 3.2 m/d, fracture storativity of 0.0007, and matrix storativity of 0.006.

73

At a cross-hole scale, it appears that ash-flow tuff might be slightly more permeable than silicic to intermediate lava flows, and that zeolitic to argillic alteration decreases the permeability of tuffaceous rocks. In 55 analyses, the hydraulic conductivity of nonwelded to densely welded ash-flow tuff ranged from 0.095 to 74 m/d and had a geometric mean value of 6.1 m/d, whereas in 11 analyses, the hydraulic conductivity of silicic to intermediate lava flows ranged from 0.60 to 20 m/d and had a geometric mean value of 4.2 m/d. In 26 analyses, the hydraulic conductivity of unaltered tuffaceous rocks ranged from 0.095 to 74 m/d and had a geometric mean value of 6.4 m/d, whereas in 11 analyses, the hydraulic conductivity of zeolitized to argillized tuffaceous rocks ranged from 0.82 to 8.5 m/d and had a geometric mean value of 3.2 m/d. At Yucca Mountain, cross-hole-scale hydraulic conductivity ranges from 1.4 to 32 m/d and appears to be independent of stratigraphy in the saturated zone. Increased hydraulic conductivity appears to be related to the Midway Valley, Bow Ridge, and Ghost Dance Faults, and to the area where the Midway Valley, Bow Ridge, Dune Wash, and East Ridge Faults terminate in close proximity. Decreased hydraulic conductivity appears to be related to the Solitario Canyon, Pagany Wash, Sever Wash, Paintbrush Canyon, and Fortymile Wash Faults. At Pahute Mesa, cross-hole-scale hydraulic conductivity ranges from 0.62 to 20 m/d. It appears to be somewhat dependent on the distribution of tuff and lava flows in the saturated zone and independent of numerous northerly striking faults that transect the mesa. Hydraulic conductivity clearly increases toward the topographic margins of the Silent Canyon Caldera Complex, possibly as a result of increased fracturing in collapse blocks at caldera margins. APPENDIX A CONVERSION FACTORS, ABBREVIATIONS, AND VERTICAL DATUM Multiply: cubic meter per day (m3/d) centimeter (cm) kilometer (km) kilopascal (kPa) liter (L) liter per second m (L/s) meter (m) meter per day (m/d) meter cubed per day (m3/d) meter squared per day (m2/d) meter squared per day (m2/d) meter squared per day (m2/d) square meter (m2) square kilometer (km2)

By: 35.313 0.3937 0.62136 0.14503 0.26417 15.852 3.2808 3.2808 0.1834 10.7636 0.05591 80.51 10.7636 0.3861

To obtain: cubic foot per day inch mile pound per square inch gallon gallon per minute foot foot per day gallon per minute foot squared per day gallon per minute per foot gallon per day per foot square foot square mile

Note: To convert °C to °F, use the following equation: °F = (1.8 × °C) + 32. Sea level: Altitudes in this report are referenced to the National Geodetic Vertical Datum of 1929 (NGVD of 1929), a geodetic datum derived from a general adjustment of the first-order level nets of the United States and Canada, which is called mean sea level in this report. AMSL in this report is above mean sea level.

74

A.L. Geldon

APPENDIX B: SUMMARY DATA FROM HYDRAULIC TESTS IN THE DEATH VALLEY REGION, INCLUDING SOME SUPPLEMENTARY DATA FROM GEOLOGICALLY SIMILAR AREAS IN THE SOUTHWESTERN UNITED STATES Observation well

UTM east coordinate (m)

UTM north coordinate (m)

Altitude (m AMSL)

Well depth (m)

Top (m)

Bottom (m)

SWL (m below LSD)

Radius or interwell distance (m)

106.0

0.19

Channel and floodplain alluvium

Silty, gravelly sand and sandy gravel

Geologic Unit

Lithologic description

QUATERNARY-TERTIARY FAN, FLOODPLAIN, AND STREAM ALLUVIUM NC-EWDP-19D

549,237.96

4,058,259.96

818.9

438.4

124.5

242.3

NC-EWDP-19IM2

549,237.96

4,058,259.96

819.3

294.3

116.6

242.5

ND

20.6

Channel and floodplain alluvium

Silty, gravelly sand and sandy gravel

Franklin Lake #14

555,362.30

4,013,299.42

610.3

17.7

1.4

17.7

1.4

0.11

Channel and floodplain alluvium

Silty to clayey gravel and sand

Doing well

553,288.05

4,055,086.07

807.7

146.3

108.2

146.3

106.7

495.5

Fan and floodplain alluvium

Bouldery gravel and gravelly sand

Washburn # 4089

549,746.28

4,053,647.01

783.9

151.8

77.8

151.8

77.8

0.25

Fan and floodplain alluvium

Bouldery gravel and gravelly sand

Watertown 3 WW

603,380.32

4,124,241.08

1,355.1

113.1

32.6

111.6

32.6

0.15

Channel and floodplain alluvium

Fine to coarse sand and gravel

HTH-2

568,502.28

4,275,546.72

1,836.4

304.8

172.3

304.8

172.3

153.8

Fan and floodplain alluvium

Gravelly, clayey sand with cobbles

HC-SO-1

568,520.40

4,259,559.18

1,714.8

146.3

68.9

140.2

77.7

152.4

Fan and floodplain alluvium

Silty to clayey gravel and sand

HC-S-O-2

558,517.10

4,244,932.51

1,678.8

138.7

92.5

132.0

92.5

152.4

Fan and floodplain alluvium

Silty to clayey gravel and sand

RE-VF-O1

558,226.05

4,218,510.43

1,630.7

214.0

97.9

123.4

96.6

152.4

Fan and floodplain alluvium

Sand, gravel, and boulders

RE-VF-O1

558,226.05

4,218,510.43

1,630.7

214.0

201.2

214.0

96.6

152.4

Fan and floodplain alluvium

Sand, gravel, and boulders

BG-VF-T1

584,748.47

4,264,219.66

1,771.2

174.6

142.6

174.6

142.6

0.13

Fan and floodplain alluvium

Sand, gravel, and boulders

CL-VF-O-1

645,385.88

4,186,435.58

1,562.1

442.6

348.1

442.6

262.7

167.6

Channel and floodplain alluvium

Sand, gravel, and boulders

DM-OW-2

688,497.72

4,146,078.06

1,435.6

299.0

264.4

296.0

264.4

152.4

Fan and floodplain alluvium

Silty to clayey sand and gravel with boulders

DL-OW-2

697,594.47

4,175,155.68

1,415.8

397.8

233.2

239.3

116.7

144.8

Fan and floodplain alluvium

Silty to clayey sand and gravel with boulders

DL-OW-2

697,594.47

4,175,155.68

1,415.8

397.8

387.1

393.2

116.7

144.8

Fan and floodplain alluvium

Silty to clayey sand and gravel with boulders

MS-VFO-1

689,561.72

4,231,891.30

1,688.6

381.9

326.4

345.6

80.5

100.6

Fan and floodplain alluvium

Silty to clayey sand and gravel with boulders

GN-IO-2

626,196.63

4,209,480.67

1,701.7

335.0

249.9

308.2

132.4

152.4

Fan alluvium

Silty to clayey sand and gravel with boulders

HM-SO-1

744,326.39

4,265,517.85

1,778.2

159.1

97.5

128.0

53.0

152.4

Fan alluvium

Silty to clayey sand and gravel with boulders

RR-S-O-1

580,197.90

4,222,836.37

1,526.4

150.9

99.1

150.9

71.0

125.3

Fan alluvium

Silty to clayey sand and gravel with boulders

RR-S-O-2

632,441.07

4,287,520.91

1,563.0

182.9

85.3

176.2

85.3

146.3

Fan alluvium

Silty to clayey sand and gravel with boulders

AIP-1

663,679.50

4,135,529.56

1,079.9

239.0

37.1

88.4

ND

0.16

Fan and floodplain alluvium

Sandy gravel with fine sand and clay layers

RNM-1

592,131.76

4,075,692.84

956.0

358.6

253.1

274.3

240.2

91.0

Fan and floodplain alluvium

Sand and gravelly sand with thin clay layers

UE-5c WW

590,978.01

4,077,005.63

980.2

817.5

245.2

383.1

245.2

0.22

Fan and floodplain alluvium

Sand and gravelly sand with thin clay layers

Water Well 5a

592,982.61

4,070,370.54

942.7

277.4

212.4

277.4

212.1

0.14

Fan and floodplain alluvium

Gravelly sand, sand, and silty sand

Water Well 5b

591,986.26

4,073,102.55

942.5

274.3

209.4

274.3

208.5

0.14

Fan and floodplain alluvium

Gravelly sand, sand, and silty sand

Water Well 5c

592,471.81

4,071,751.81

939.1

362.4

270.4

362.4

211.1

0.16

Fan and floodplain alluvium

Sandy cobble-gravel with thin silt layers

Test Well A

585,724.75

4,099,201.82

1,221.3

570.0

489.2

570.0

489.2

0.16

Fan and floodplain alluvium

Silty to clayey gravel and sand

ODL-O-U

412,628.98

4,044,394.62

1,093.3

181.4

45.7

85.3

-12.2

103.6

Channel and floodplain alluvium

Sand with thin clay and silt layers

QUATERNARY-TERTIARY PLAYA AND SPRING DEPOSITS Franklin Lake #5

556,386.71

4,010,272.59

609.6

10.4

1.9

10.4

1.9

0.11

Playa deposits

Clay with silt and fine sand layers

Franklin Lake #7

556,611.79

4,010,207.50

609.7

5.5

2.8

5.5

3.5

0.079

Playa deposits

Clay with silt and fine sand layers

Franklin Lake #10

556,189.59

4,010,182.58

609.0

11.5

1.6

11.5

2.3

0.13

Playa deposits

Clay with silt and fine sand layers

Franklin Lake GS-4

557,867.32

4,011,174.95

611.4

5.7

5.4

5.7

1.0

0.026

Playa deposits

Clay with silt and fine sand layers

CV-I-O-1

685,754.69

4,259,838.94

1,831.6

139.6

70.5

80.2

70.5

152.4

Playa deposits

Clay and silt with sand and gravel layers

Spring Meadows #1

565,962.40

4,028,520.78

707.4

120.4

47.2

120.4

3.0

411.9

Playa and spring deposits

Clay, marl, and limestone with gravel

Spring Meadows #2

565,632.46

4,028,274.23

703.5

91.4

18.3

91.4

2.4

411.9

Playa and spring deposits

Clay, marl, and limestone with gravel

Spring Meadows #4

565,012.12

4,028,480.31

702.3

152.4

30.5

152.4

3.4

1,096

Playa and spring deposits

Clay, marl, and limestone with gravel

18S/51-07db2

565,390.17

4,028,294.58

702.6

86.0

12.2

86.0

3.0

243.1

Playa and spring deposits

Clay, marl, and limestone

Spring Meadows #3

565,965.44

4,028,121.46

703.5

237.7

3.0

237.7

flowing

399.3

Playa and spring deposits

Clay, limestone, and sandstone

Spring Meadows #13

564,838.00

4,028,978.18

711.3

142.6

40.2

142.6

8.2

813.4

Playa and spring deposits

Limestone, marl, clay, gypsum, sand, and gravel

4,275,398.56

1,832.1

1,126.2

804.9

826.2

169.2

0.16

Tuffaceous rocks of Slanted Buttes

Conglomerate and gravelly sandstone with siltstone and tuff

TERTIARY SEDIMENTARY ROCKS HTH-1

568,543.15

Implications for groundwater flow in the Southwest Nevada Volcanic Field

Test start

Test end

Test length (min)

Test type

Production well

Discharge or injection rate (L/s)

Analyzed Data

Kr (m/d)

Kz (m/d)

T (m2/d)

Storativity

Specific yield

75

Analyical method

Sources of hydraulicproperty data, test analyses, and supporting information

QUATERNARY-TERTIARY FAN, FLOODPLAIN, AND STREAM ALLUVIUM 07/07/00

07/14/00

10,080

Pumping

Same

9.41

Drawdown

0.27

ND

21

ND

ND

Hantush (1961)* USGS files

01/29/02

02/04/02

ND

ND

8,250

Pumping

NC-EWDP-19D

6.89

Drawdown

3.8

ND

320

0.0008

ND

Theis (1935)*

USGS files

91

Pumping

Same

1.0

Residual drawdown

2.7

ND

44

ND

ND

Theis (1935)

Czarnecki (1997)

06/10/99

06/12/99

2,867

Pumping

Airport well

83.9

Drawdown

6.4

ND

200

0.0003

ND

Hantush and Jacob (1955)

Questa Engineering Corp. (2000a)

07/12/62

07/12/62

180

Pumping

Same

0.53

Drawdown

13

ND

300

ND

ND

Theis (1935)

Thordarson and Rush (unpublished)

11/23/59

11/23/59

1,297

Pumping

Same

10.4

Residual drawdown

8.8

ND

340

ND

ND

Theis (1935)

Schoff (1962)

08/18/67

08/25/67

10,008

Pumping

HTH-1

7.7

Drawdown

0.92

0.66

98

0.003

0.20

Neuman (1975)* Dinwiddie and Schroder (1971)

Sept-80

Sept-80

5,820

Pumping

HC-ST-1

14.8

Drawdown

25

ND

1,800

0.001

0.020

Neuman (1975)

Sept-80

Sept-80

7,200

Pumping

HC-S-T-2

23.7

Drawdown

3.8

ND

150

0.0001

0.004

Neuman (1975)

Bunch and Harrill (1984)

Apr-81

Apr-81

10,200

Pumping

RE-VF-T1

34.7

Drawdown

18

ND

460

0.0001

0.012

Neuman (1975)

Bunch and Harrill (1984)

Neuman (1975)

Bunch and Harrill (1984)

Cooper and Jacob (1946)

Bunch and Harrill (1984)

Neuman (1975)

Bunch and Harrill (1984)

Cooper and Jacob (1946)

Bunch and Harrill (1984)

Apr-81

Apr-81

10,200

Pumping

RE-VF-T1

34.7

Drawdown

73

ND

930

0.0002

0.002

May-81

May-81

14,400

Pumping

Same

27.4

Drawdown

7.6

ND

240

ND

ND

Bunch and Harrill (1984)

Jun-81

Jun-81

240

Pumping

CL-VF-T-1A

28.4

Drawdown

3.6

ND

340

0.0004

0.001

May-80

May-80

3,780

Pumping

DM-TW-2

5.36

Drawdown

3.2

ND

100

ND

ND

Apr-80

Apr-80

14,340

Pumping

DL-TW-2

18.9

Drawdown

52

ND

320

0.0005

0.013

Neuman (1975)

Bunch and Harrill (1984)

Apr-80

Apr-80

14,340

Pumping

DL-TW-2

18.9

Drawdown

56

ND

340

0.004

0.051

Neuman (1975)

Bunch and Harrill (1984)

Jul-81

Jul-81

8,640

Pumping

MS-VFT-1

1.89

Drawdown

0.62

ND

3.6

0.0001

0.0004

Neuman (1975)

Bunch and Harrill (1984)

Nov-80

Nov-80

43,200

Pumping

GN-IT-2

32.2

Drawdown

19

ND

1,100

0.0006

0.003

Neuman (1975)

Bunch and Harrill (1984)

Sept-80

Sept-80

7,200

Pumping

HM-ST-1

6.94

Drawdown

7.6

ND

230

0.0002

0.010

Neuman (1975)

Bunch and Harrill (1984)

Sept-80

Sept-80

12,960

Pumping

RR-S-T-1

46.2

Drawdown

20

ND

1,000

0.0002

0.060

Neuman (1975)

Bunch and Harrill (1984)

Oct-80

Nov-80

40,560

Pumping

RR-S-T-2

44.5

Drawdown

8.1

ND

730

0.0003

0.001

Neuman (1975)

Bunch and Harrill (1984)

08/21/99

08/22/99

1,440

Pumping

Same

25.9

Drawdown

6.3

ND

320

ND

ND

Neuman (1975)

Consulting Engineering Services (1999)

10/11/75

10/13/75

2,699

Pumping

RNM-2S

18.4

Recovery

46

0.99

970

0.005

0.08

Neuman (1975)* Bryant (1992); USGS files

10/11/64

10/11/64

420

Pumping

Same

21.1

Drawdown

0.1

ND

13

ND

ND

Neuman (1975)* Gillespie et al. (1996)

10/07/59

10/08/59

1,485

Pumping

Same

6.32

Drawdown

0.6

ND

30

ND

ND

Theis (1935)

Hood (1961)

08/27/59

08/29/59

2,886

Pumping

Same

10.2

Drawdown

1.4

ND

90

ND

ND

Theis (1935)

Hood (1961)

09/09/59

09/11/59

2,703

Pumping

Same

8.29

Drawdown

0.34

ND

31

ND

ND

Theis (1935)

Hood (1961)

09/20/60

09/21/60

2,290

Pumping

Same

3.78

Drawdown

0.17

ND

14

ND

ND

Neuman (1975)* Price and Thordarson (1961)

01/23/91

05/16/91

162,720

Pumping

ODL-T-U

103

Drawdown

16

ND

640

0.0003

ND

Theis (1935)*

Jacobson et al. (1992)

QUATERNARY-TERTIARY PLAYA AND SPRING DEPOSITS ND

ND

110

Slug-injection

Same

NA

Recovery

0.045

ND

0.38

ND

ND

Cooper et al. (1967)

Czarnecki (1997)

ND

ND

27

Slug-injection

Same

NA

Recovery

1.2

ND

3.2

ND

ND

Cooper et al. (1967)

Czarnecki (1997)

ND

ND

1,440

Slug-injection

Same

NA

Recovery

0.0034

ND

0.034

ND

ND

Cooper et al. (1967)

Czarnecki (1997)

ND

ND

67

Slug-injection

Same

NA

Recovery

1.4

ND

0.42

ND

ND

Cooper et al. (1967)

Czarnecki (1997)

10/25/80

10/25/80

160

Pumping

CV-I-T-1

14.2

Drawdown

23

ND

220

0.00009

0.013

Neuman (1975)

Bunch and Harrill (1984)

04/05/71

04/06/71

1,200

Pumping

Spring Meadows #2

75.7

Drawdown

10

ND

420

0.003

ND

Boulton (1963)

Dudley and Larson (1976)

03/08/71

03/09/71

1,440

Pumping

Spring Meadows #1

104.1

Drawdown

50

ND

1,300

0.04

ND

Boulton (1963)

Dudley and Larson (1976)

03/22/71

03/22/71

540

Pumping

Spring Meadows #5

113.6

Drawdown

19

ND

1,800

0.03

ND

Boulton (1963)

Dudley and Larson (1976)

04/05/71

04/06/71

1,200

Pumping

Spring Meadows #2

75.7

Drawdown

27

ND

1,200

0.03

ND

Boulton (1963)

Dudley and Larson (1976)

03/08/71

03/09/71

1,440

Pumping

Spring Meadows #1

104.1

Drawdown

29

ND

810

0.001

ND

Boulton (1963)

Dudley and Larson (1976)

03/22/71

03/22/71

540

Pumping

Spring Meadows #5

113.6

Drawdown

24

ND

1,700

0.002

ND

Boulton (1963)

Dudley and Larson (1976)

Slug-injection

Same

NA

Recovery

0.056

ND

1.2

ND

ND

Cooper et al. (1967)

Dinwiddie (1968, 1970a)

TERTIARY SEDIMENTARY ROCKS 08/01/67

08/01/67

70

76

A.L. Geldon

Observation well

UTM east coordinate (m)

UTM north coordinate (m)

Altitude (m AMSL)

Well depth (m)

Top (m)

Bottom (m)

SWL (m below LSD)

Radius or interwell distance (m)

HTH-1

568,543.15

4,275,398.56

1,832.1

1,126.2

899.4

917.7

170.1

0.16

Tuffaceous rocks of Slanted Buttes

Conglomerate and gravelly sandstone with siltstone and tuff

HTH-1

568,543.15

4,275,398.56

1,832.1

1,126.2

1,094.5

1,117.4

168

0.16

Tuffaceous rocks of Slanted Buttes

Tuffaceous sandstone and siltstone with conglomerate and clay

HTH-21-1

580,377.29

4,271,115.80

1,786.8

1,981.1

1,358.1

1,416.0

147.8

0.12

Tuffaceous rocks of Slanted Buttes

Gravelly sandstone, sandstone, siltstone, limestone, and tuff

UCe-17

568,049.79

4,281,240.26

1,995.4

2,431.7

1,868.9

1,929.9

ND

0.13

Needles area lacustrine sediments

Siltstone and limestone with tuff

Water well 3

583,827.33

4,094,553.48

1,209.8

548.6

479.1

548.6

479.1

0.10

Pavits Spring Formation

Sandstone, conglomerate, and tuff

Klondike #2

477,523.32

4,191,556.32

1,507.8

125.0

76.2

125.0

58.9

0.33

Older basin fill of Plume (1996)

Gravelly sandstone with claystone

Klondike #1

478,427.61

4,191,614.91

1,514.3

125.6

76.2

125.6

59.0

0.30

Older basin fill of Plume (1996)

Gravelly sandstone with claystone

Duckwater Creek 8-12

622,682.41

4,279,783.43

1,460.0

2,106.2

1,437.7

1,505.7

ND

0.089

Muddy Creek Formation (?)

Mudstone, calcareous shale, sandstone and conglomerate

Duckwater Federal 9-1

624,422.39

4,307,560.26

1,713.3

2,168.7

1,842.8

1,869.9

ND

0.089

Sheep Pass Formation

Calcareous shale and shaly limestone

Currant #1

627,831.99

4,284,304.25

1,491.1

2,377.4

2,202.5

2,210.1

ND

0.089

Sheep Pass Formation

Calcareous shale and shaly limestone

Adobe Federal 19-1

650,521.49

4,208,938.44

1,527.7

2,348.8

813.8

827.8

ND

0.089

Muddy Creek Formation (?)

Mudstone, calcareous shale, sandstone and conglomerate

White River Valley #6

664,823.01

4,261,208.53

1,595.9

1,921.8

667.5

678.2

ND

0.089

Muddy Creek Formation (?)

Mudstone, calcareous shale, sandstone and conglomerate

Sunnyside #1

670,376.40

4,247,352.16

1,621.8

1,996.4

439.5

478.8

ND

0.089

Sheep Pass Formation

Calcareous shale and shaly limestone

Geologic Unit

Lithologic description

YOUNGER TERTIARY TUFF AND LAVA FLOWS UE-2aw

582,754.70

4,109,804.66

1,302.1

709.6

559.0

614.2

554.5

0.16

Rainier Mesa Tuff

NW-DW ash-flow tuff and vitrophyre

Water Well 4a

586,641.92

4,084,387.53

1,099.0

457.8

324.9

457.8

254.8

371.1

Rainier Mesa and Topopah Spring Tuffs

Fractured, NW-DW ash-flow tuff

UE-18r

549,320.55

4,109,758.46

1,688.0

1,525.2

496.5

1,184.4

418.2

0.13

Ammonia Tanks Tuff

PW-DW ash-flow tuff with rhyolite lava

UE-18r

549,320.55

4,109,758.46

1,688.0

1,525.2

1,184.4

1,525.2

418.4

0.13

Rainier Mesa Tuff

Heterolithic megabreccia (debris flow)

UE-19c

560,338.52

4,124,701.04

2,143.7

2,587.4

737.9

1,377.7

714.9

0.13

Dead Horse Flat Formation

Comendite lava flow

UE-19e

559,087.72

4,127,818.57

2,108.9

1,830.3

754.4

831.8

676.1

0.13

Bullfrog Tuff

Rhyolite lava flow

UE-19e

559,087.72

4,127,818.57

2,108.9

1,830.3

894.0

1,670.9

676.1

0.13

Dead Horse Flat Formation

Comendite lava flow

UE-19e

559,087.72

4,127,818.57

2,108.9

1,830.3

1,670.9

1,769.1

676.1

0.13

Trachyte of Muenster

Trachyte lava flow

UE-19e

559,087.72

4,127,818.57

2,108.9

1,830.3

1,769.1

1,830.3

676.1

0.13

Grouse Canyon Tuff

DW ash-flow tuff

UE-19fs

556,112.99

4,119,785.62

2,052.9

2,118.4

781.8

1,456.6

702.9

0.15

Rhyolite of Inlet

Rhyolite lava flows

UE-19gs

556,297.15

4,129,062.88

2,048.0

2,286.0

807.7

1,374.0

622.7

0.13

Dead Horse Flat Formation

Comendite lava flows and NW-PW ash-flow tuff

UE-19i

557,917.29

4,122,602.24

2,084.5

2,438.4

882.7

2,438.4

688.2

0.14

Bullfrog Tuff

Rhyolite lava flows with PW ash-flow tuff

U-20a-2 WW

551,344.54

4,121,758.22

1,972.7

1,371.6

629.7

1,371.6

629.7

0.13

Calico Hills Formation

Rhyolite lava flows

UE-20d

546,093.66

4,122,282.46

1,905.9

1,369.2

745.5

919.3

632.3

25.9

Tiva Canyon Tuff

MW-DW ash-flow tuff

UE-20d

546,093.66

4,122,282.46

1,905.9

1,369.2

745.5

1,184.0

632.3

25.9

Tiva Canyon Tuff

MW-DW ash-flow tuff

UE-20e-1

548,119.03

4,129,967.24

1,919.3

1,949.2

556.2

1,949.2

556.2

0.13

Calico Hills Formation

Pumiceous rhyolite lava flows and flow breccia

UE-20f

545,389.67

4,124,898.04

1,864.3

4,171.5

1,358.2

1,704.8

541.5

0.11

Rhyolite of Inlet

Partly brecciated rhyolite lava flow

UE-20f

545,389.67

4,124,898.04

1,864.3

4,171.5

2,521.6

2,974.2

541.5

0.11

Dead Horse Flat Formation

Partly brecciated comendite lava flows

UE-20f

545,389.67

4,124,898.04

1,864.3

4,171.5

2,974.2

3,011.1

541.5

0.11

Grouse Canyon Tuff

Silicified, NW ash-flow tuff

ER-20-6#1

551,362.79

4,123,691.98

1,973.5

898.2

764.1

898.2

618.1

131.4

Calico Hills Formation

Rhyolite lava flows

ER-20-6#2

551,328.04

4,123,661.93

1,973.6

897.6

764.4

897.6

618.4

89.1

Calico Hills Formation

Rhyolite lava flows

Implications for groundwater flow in the Southwest Nevada Volcanic Field

Test start

Test end

Test length (min)

Test type

Production well

Discharge or injection rate (L/s)

Analyzed Data

Kr (m/d)

Kz (m/d)

T (m2/d)

Storativity

Specific yield

07/31/67

07/31/67

60

Slug-injection

Same

NA

Recovery

0.27

ND

4.9

ND

07/30/67

07/31/67

245

Swabbingrecovery

Same

0.32

Residual drawdown

0.00035

ND

0.0081

08/27/68

08/27/68

200

Slug-injection

Same

NA

Recovery

0.10

ND

06/23/67

06/23/67

30

Slug-injection

Same

NA

Recovery

0.000043

10/02/59

10/04/59

2,881

Pumping

Same

2.54

Drawdown

10/30/92

11/01/92

2,850

Pumping

Same

18.9

Drawdown

07/24/81

07/24/81

600

Pumping

Same

41.0

Jul-79

Jul-79

140

Drill-stem

Same

Dec-84

Dec-84

180

Drill-stem

Oct-78

Oct-78

120

Oct-79

Oct-79

1981 Aug-86

77

Analyical method

Sources of hydraulicproperty data, test analyses, and supporting information

ND

Cooper et al. (1967)

Dinwiddie (1968, 1970a)

ND

ND

Theis (1935) recovery *

Dinwiddie (1968, 1970a)

6.0

ND

ND

Cooper et al. (1967)*

Dinwiddie and Schroder (1971)

ND

0.0026

ND

ND

Cooper et al. (1967)

Dinwiddie (1968, 1970a)

0.64

ND

16

ND

ND

Theis (1935)

Hood (1961)

2.7

ND

50

ND

ND

Hantush (1961)* City of Goldfield (unpublished data)

Drawdown

4.2

ND

170

ND

ND

Hantush (1961)* City of Goldfield (unpublished data)

0.33

Recovery

0.00026

ND

0.018

ND

ND

Earlougher (1977)*

McKay and Kepper (1988)

Same

0.38

Recovery

0.000096

ND

0.0026

ND

ND

Earlougher (1977)*

McKay and Kepper (1988)

Drill-stem

Same

0.19

Recovery

0.0073

ND

0.055

ND

ND

Horner (1951)

McKay and Kepper (1988)

120

Drill-stem

Same

ND

Recovery

0.00093

ND

0.013

ND

ND

Horner (1951)

McKay and Kepper (1988)

1981

120

Drill-stem

Same

ND

Recovery

0.00049

ND

0.0053

ND

ND

Horner (1951)

McKay and Kepper (1988)

Aug-86

110

Drill-stem

Same

0.28

Recovery

0.011

ND

0.42

ND

ND

Horner (1951)

McKay and Kepper (1988) Quinlivan et al. (1977); USGS files

YOUNGER TERTIARY TUFF AND LAVA FLOWS 01/31/74

02/02/74

80 - 780

Slug-injection

Same

NA

Recovery

0.086

ND

4.8

ND

ND

Cooper et al. (1967)*

02/22/90

02/25/90

4,320

Pumping

Water Well 4

36.3

Drawdown

20

ND

2,100

0.002

ND

Streltsova-Adams Gillespie et al. (1996); (1978)* USGS files

01/28/68

01/29/68

2,820

Pumping

Same

15.1

Drawdown

7.3

ND

260

ND

ND

Cooper and Jacob (1946)*

Blankennagel and Weir (1973)

01/28/68

01/29/68

2,820

Pumping

Same

15.1

Drawdown

0.37

ND

21

ND

ND

Cooper and Jacob (1946)*

Blankennagel and Weir (1973)

05/07/64

05/08/64

2,045

Pumping

Same

3.72

Drawdown

0.45

ND

39

ND

ND

Theis (1935)*

Blankennagel and Weir (1965)

04/21/65

04/22/65

1,440

Pumping

Same

3.53

Drawdown

0.083

ND

1.7

ND

ND

Cooper (1963)*

Blankennagel and Weir (1965)

04/21/65

04/22/65

1,440

Pumping

Same

3.53

Drawdown

0.041

ND

4.1

ND

ND

Cooper (1963)*

Blankennagel and Weir (1965)

04/21/65

04/22/65

1,440

Pumping

Same

3.53

Drawdown

0.0067

ND

0.66

ND

ND

Cooper (1963)*

Blankennagel and Weir (1965)

04/21/65

04/22/65

1,440

Pumping

Same

3.53

Drawdown

0.020

ND

0.49

ND

ND

Cooper (1963)*

Blankennagel and Weir (1965)

08/17/65

08/18/65

1,440

Pumping

Same

8.20

Drawdown

0.76

ND

80

ND

ND

Cooper and Jacob (1946)

Blankennagel and Weir (1973)

03/26/65

03/27/65

1,440

Pumping

Same

11.7

Drawdown

0.21

ND

24

ND

ND

Cooper (1963)*

Blankennagel and Weir (1965)

09/02/65

09/03/65

1,000

Pumping

Same

8.83

Drawdown

0.022

ND

3.9

ND

ND

Cooper (1963)*

Blankennagel and Weir (1966)

02/10/65

02/11/65

1,740

Pumping

Same

11.7

Drawdown

0.70

ND

220

ND

ND

Cooper and Jacob (1946)

Blankennagel and Weir (1973)

07/26/66

07/26/66

178

Airlift

U-20d

9.46

Recovery

2.4

ND

110

0.01

ND

Streltsova-Adams Blankennagel et al. (1978)* (1964); USGS files

08/11/66

08/11/66

459

Airlift

U-20d

8.71

Residual drawdown

3.0

ND

140

ND

ND

Theis (1935) recovery *

Blankennagel et al. (1964); USGS files

06/04/64

06/06/64

2,393

Pumping

Same

5.93

Residual drawdown

0.56

ND

97

ND

ND

Theis (1935) recovery *

Blankennagel and Weir (1965)

08/09/64

08/11/64

2,800

Pumping

Same

6.92

Drawdown

0.0041

ND

0.24

ND

ND

Hantush (1961)* Blankennagel et al. (1964); Blankennagel and Weir (1965)

08/09/64

08/11/64

2,800

Pumping

Same

6.92

Drawdown

0.0017

ND

0.73

ND

ND

Hantush (1961)* Blankennagel et al. (1964); Blankennagel and Weir (1965)

08/09/64

08/11/64

2,800

Pumping

Same

6.92

Drawdown

0.0013

ND

0.048

ND

ND

Hantush (1961)* Blankennagel et al. (1964); Blankennagel and Weir (1965)

06/02/97

08/28/97

125,280

Pumping

ER-20-6#3

7.32

Drawdown

3.2

ND

200

0.007

ND

Streltsova-Adams IT Corporation (1998a, (1978)* 1998b)

06/02/97

06/02/97

360

Pumping

ER-20-6#3

7.32

Drawdown

2.4

ND

150

0.0003

ND

Theis (1935)

IT Corporation (1998a, 1998b)

78

A.L. Geldon

Observation well

UTM east coordinate (m)

UTM north coordinate (m)

Altitude (m AMSL)

Well depth (m)

Top (m)

Bottom (m)

SWL (m below LSD)

Radius or interwell distance (m)

PM-3

539,002.93

4,121,291.22

1,774.8

920.2

444.8

533.4

444.8

0.14

Geologic Unit

Rhyolite of Fluorspar Canyon

Lithologic description

Fractured, zeolitized, NW ash-flow tuff and bedded reworked tuff

PM-3

539,002.93

4,121,291.22

1,774.8

920.2

574.6

652.3

444.8

0.14

Tiva Canyon Tuff

Fractured, MW ash-flow tuff and tuff breccia

USW VH-1

539,986.16

4,071,717.53

963.2

762.3

277.5

762.3

183.4

0.080

Topopah Spring and Bullfrog Tuffs

Variably fractured, NW-DW ash-flow tuff

J-13

554,016.88

4,073,517.23

1,011.5

1,031.8

282.9

1,009.5

282.9

0.13

Topopah Spring Tuff

Very fractured, MW-DW ash-flow tuff

J-13

554,016.88

4,073,517.23

1,011.5

1,063.1

282.9

422.4

282.5

0.21

Topopah Spring Tuff

Very fractured, MW-DW ash-flow tuff and vitrophyre

J-13

554,016.88

4,073,517.23

1,011.5

1,063.1

471.2

502.0

282.5

0.11

Calico Hills Formation

Zeolitized, bedded, reworked tuff, ash-fall tuff, and sandstone

J-13

554,016.88

4,073,517.23

1,011.5

1,063.1

668.7

699.2

282.4

0.10

Bullfrog Tuff

Fractured, PW-MW ash-flow tuff

J-13

554,016.88

4,073,517.23

1,011.5

1,063.1

772.7

919.0

283.4

0.10

Tram Tuff

Fractured, NW-PW ash-flow tuff

USW WT-1

549,150.83

4,074,974.93

1,201.1

514.8

470.8

514.8

470.8

1,992

Calico Hills Fm and Bullfrog Tuff

Faulted, fractured, partly zeolitized, MW-DW ash-flow tuff and bedded tuff

UE-25 WT #3

552,097.72

4,072,564.11

1,030.1

348.1

300.4

348.1

300.4

3,526

Bullfrog Tuff

Faulted, variably fractured, partly zeolitized, NW-MW ash-flow tuff

UE-25 WT#4

550,445.91

4,079,419.56

1,169.2

481.6

438.4

481.6

438.4

3,573

Calico Hills Fm to Bullfrog Tuff

Faulted, fractured, rhyolite lava flow and partly zeolitized, NW-DW ash-flow tuff and bedded tuff

USW WT-11

547,532.63

4,070,438.07

1,094.1

440.7

363.5

440.7

363.5

6,414

Topopah Spring to Bullfrog Tuff

Faulted, variably fractured, partly zeolitized, NW-DW ash-flow tuff and bedded tuff

UE-25 WT#12

550,162.90

4,070,646.98

1,074.7

398.7

345.4

398.7

345.4

0.11

Topopah Spring Tuff

DW ash-flow tuff

UE-25 WT #14

552,637.97

4,077,336.62

1,076.1

399.3

346.4

399.3

346.4

2,249

Topopah Spring to Bullfrog Tuff

Faulted, variably fractured, partly zeolitized, NW-MW ash-flow tuff and bedded tuff

UE-25 a#1

549,934.40

4,078,316.74

1,199.2

762.2

468.5

762.2

468.5

107

Calico Hills Fm to Bullfrog Tuff

Faulted, variably fractured, zeolitized, and argillized, NW-MW ash-flow tuff and bedded tuff

UE-25 b#1

549,954.45

4,078,421.63

1,200.7

1,219.8

470.1

1,199

470.1

2,722

Calico Hills Fm to Bullfrog Tuff

Faulted, variably fractured, zeolitized, and argillized, NW-MW ash-flow tuff and bedded tuff

UE-25 b#1

549,954.45

4,078,421.63

1,200.7

1,219.8

477

544

470.6

0.18

Calico Hills Formation

Zeolitized, NW ash-flow tuff

UE-25 b#1

549,954.45

4,078,421.63

1,200.7

1,219.8

581

661

470.6

0.17

Prow Pass Tuff

Faulted, fractured, partly zeolitized, NW-MW ash-flow tuff

UE-25 b#1

549,954.45

4,078,421.63

1,200.7

1,219.8

743

860

470.6

0.15

Bullfrog Tuff

Partly zeolitized, NW-MW ash-flow tuff

UE-25 c#1

550,957.87

4,075,942.70

1,130.6

897.6

417.9

897.6

400.3

82.6

Calico Hills Fm to Tram Tuff

Faulted, variably fractured and altered, NWDW ash-flow tuff, bedded tuff, and tuff breccia

UE-25 c#1

550,957.87

4,075,942.70

1,130.6

902.8

417.9

486.2

400.3

78.0

Calico Hills Formation

Variably fractured, NW ash-flow tuff

UE-25 c#1

550,957.87

4,075,942.70

1,130.6

902.8

489.2

512.1

400.3

78.9

Calico Hills Formation

Zeolitized, bedded, ash-fall tuff and sandstone

UE-25 c#1

550,957.87

4,075,942.70

1,130.6

897.6

549.2

605.3

400.3

82.6

Prow Pass Tuff

Fractured, partly argillized to zeolitized, NWMW ash-flow tuff

UE-25 c#1

550,957.87

4,075,942.70

1,130.6

897.6

549.3

605.3

400.4

81.1

Prow Pass Tuff

Fractured, partly argillized to zeolitized, NWMW ash-flow tuff

UE-25 c#1

550,957.87

4,075,942.70

1,130.6

897.6

607.2

698.3

400.5

83.2

(upper) Bullfrog Tuff

Variably fractured, argillized, and zeolitized, NW-PW ash-flow tuff and bedded tuff

UE-25 c#1

550,957.87

4,075,942.70

1,130.6

897.6

700.1

797.1

400.7

85.6

(lower) Bullfrog Tuff

Variably fractured, argillized, and zeolitized, NW-DW ash-flow tuff

UE-25 c#1

550,957.87

4,075,942.70

1,130.6

897.6

798.9

869.9

400.6

86.9

(upper) Tram Tuff

Faulted, variably fractured and altered, NWPW ash-flow tuff, tuff breccia, and bedded tuff

UE-25 c#1

550,957.87

4,075,942.70

1,130.6

902.8

793.4

902.8

400.3

85.3

Tram Tuff

Faulted, variably fractured and altered, NWPW ash-flow tuff, tuff breccia, and bedded tuff

UE-25 c#2

550,943.92

4,075,867.37

1,132.2

910.1

416.0

910.1

402.1

29.0

Calico Hills Fm to Tram Tuff

Faulted, variably fractured and altered, NWDW ash-flow tuff, bedded tuff, and tuff breccia

UE-25 c#2

550,943.92

4,075,867.37

1,132.2

911.4

416.1

911.4

401.8

29.0

Calico Hills Fm to Tram Tuff

Faulted, variably fractured and altered, NWDW ash-flow tuff, bedded tuff, and tuff breccia

UE-25 c#2

550,943.92

4,075,867.37

1,132.2

910.1

416.0

531.3

402.1

29.0

Calico Hills Formation

Variably fractured, NW ash-flow tuff and bedded tuff

UE-25 c#2

550,943.92

4,075,867.37

1,132.2

910.1

533.1

605.6

402.1

28.6

Prow Pass Tuff

Fractured, partly argillized to zeolitized, NWMW ash-flow tuff

UE-25 c#2

550,943.92

4,075,867.37

1,132.2

910.1

607.5

696.5

401.4

28.6

(upper) Bullfrog Tuff

Variably fractured, argillized, and zeolitized, NW-PW ash-flow tuff and bedded tuff

UE-25 c#2

550,943.92

4,075,867.37

1,132.2

910.1

698.3

791.9

402.6

29.3

(lower) Bullfrog Tuff

Faulted, variably fractured, argillized, and zeolitized, NW-DW ash-flow tuff

UE-25 c#2

550,943.92

4,075,867.37

1,132.2

910.1

793.7

869.6

402.5

29.9

(upper) Tram Tuff

Faulted, variably fractured and altered, NWPW ash-flow tuff, tuff breccia, and bedded tuff

Implications for groundwater flow in the Southwest Nevada Volcanic Field

79

Test start

Test end

Test length (min)

Test type

Production well

Discharge or injection rate (L/s)

Analyzed Data

Kr (m/d)

Kz (m/d)

T (m2/d)

Storativity

Specific yield

Analyical method

Sources of hydraulicproperty data, test analyses, and supporting information

09/26/88

09/27/88

1,860

Pumping

Same

10.7

Drawdown

0.17

ND

3.1

ND

ND

Neuman (1975)* Kilroy and Savard (1996)

09/26/88

09/27/88

1,860

Pumping

Same

10.7

Drawdown

0.055

ND

3.4

ND

ND

Neuman (1975)* Kilroy and Savard (1996)

02/10/81

02/11/81

1,140

Pumping

Same

15.0

Drawdown

3.5

ND

540

ND

ND

Streltsova-Adams Thordarson and Howells (1978)* (1987)

02/18/64

02/22/64

5,765

Pumping

Same

44.0

Drawdown

1.2

ND

140

ND

ND

Stallman (1965)

Thordarson (1983)

12/30/62

01/01/63

3,155

Pumping

Same

27.1

Drawdown

1.0

ND

120

ND

ND

Stallman (1965)

Thordarson (1983)

ND

ND

20

Slug-injection

Same

NA

Recovery

0.15

ND

4.5

ND

ND

Cooper et al. (1967)

Thordarson (1983)

ND

ND

200

Slug-injection

Same

NA

Recovery

0.016

ND

0.48

ND

ND

Cooper et al. (1967)

Thordarson (1983)

ND

ND

62-180

Swabbingrecovery

Same

NA

Recovery

0.0056

ND

0.82

ND

ND

Theis (1935) Thordarson (1983) recovery ; Cooper et al. (1967)*

05/08/96

08/07/97

656,829

Pumping

UE-25 c#3

9.29

Drawdown

9.7

ND

630

0.01

ND

Cooper and Jacob (1946)*

05/08/96

09/16/97

714,387

Pumping

UE-25 c#3

9.27

Drawdown

15

ND

800

0.01

ND

Streltsova-Adams Geldon et al. (2002) (1978)*

05/08/96

07/15/97

623,649

Pumping

UE-25 c#3

9.31

Drawdown

8.8

ND

960

0.002

ND

Cooper and Jacob (1946)*

Graves (1998, 2000); Geldon (1999, 2000)

05/08/96

07/16/97

625,203

Pumping

UE-25 c#3

9.31

Drawdown

9.0

ND

980

0.002

ND

Cooper and Jacob (1946)*

Graves (1998, 2000); Geldon (1999, 2000)

09/05/95

09/11/95

9,105

Pumping

Same

1.27

Drawdown

1.6

ND

5.8

ND

ND

Cooper and Jacob (1946)

O’Brien (1997)

05/08/96

12/02/96

300,000

Pumping

UE-25 c#3

9.59

Drawdown

4.2

ND

710

0.002

ND

Walton (1970)*

Geldon et al. (2002)

08/29/81

09/01/81

3,680

Pumping

UE-25 b#1

35.7

Drawdown

7.8

0.81

850

0.0009

0.07

Neuman (1975)* Moench (1984)

05/08/96

08/06/97

655,416

Pumping

UE-25 c#3

9.29

Drawdown

9.0

ND

980

0.004

ND

Cooper and Jacob (1946)*

Graves (1998, 2000); Geldon (1999, 2000)

05/11/81

08/13/81

27 - 120

Slug-injection

Same

NA

Recovery

0.15

ND

10

ND

ND

Cooper et al. (1967)

Lahoud et al. (1984)

08/13/81

08/13/81

3.0 - 59

Slug-injection

Same

NA

Recovery

0.49

ND

39

ND

ND

Cooper et al. (1967)

Lahoud et al. (1984)

08/11/81

08/12/81

3.3 - 50

Slug-injection

Same

NA

Recovery

0.45

ND

53

ND

ND

Cooper et al. (1967)

Lahoud et al. (1984)

06/01/95

06/09/95

11,400

Pumping

UE-25 c#3

17.9

Recovery

7.3

0.27

1,800

0.001

0.01

Neuman (1975)

Geldon et al. (1998)

05/04/84

05/14/84

13,625

Pumping

UE-25 c#3

26.4

Drawdown

0.095

0.19

5.3

ND

0.001

Neuman (1975)

Geldon (1996)

05/14/84

06/12/84

40,010

Pumping

UE-25 c#3

26.4

Recovery

0.82

ND

4.0

ND

0.002

Neuman (1975)

Geldon (1996)

06/02/98

06/11/98

12,500

Pumping

UE-25 c#2

0.33

Drawdown

3.4

ND

65

ND

ND

Cooper (1963)*

Geldon et al. (1999)

06/12/95

06/16/95

5,803

Pumping

UE-25 c#3

22.5

Drawdown

3.2

ND

60

0.0003

ND

Theis (1935)

Geldon et al. (2002)

06/16/95

06/21/95

5,708

Pumping

UE-25 c#3

22.5

Recovery

2.0

ND

90

0.00006

ND

Theis (1935)

Geldon et al. (2002)

05/08/96

03/26/97

464,100

Pumping

UE-25 c#3

9.53

Drawdown

20

ND

1,300

0.002

ND

Streltsova-Adams Geldon et al. (2002) (1978)

02/08/96

02/13/96

6,984

Pumping

UE-25 c#3

8.49

Drawdown

13

ND

700

0.0001

ND

Theis (1935)

Geldon et al. (2002)

10/30/84

11/15/84

22,786

Pumping

UE-25 c#3

26.8

Drawdown

12

ND

730

0.003

ND

Cooper (1963)

Geldon (1996)

05/22/95

06/01/95

14,403

Pumping

UE-25 c#3

17.9

Drawdown

13

1.7

2,100

0.003

0.2

Neuman (1975)

Geldon et al. (1998)

05/09/84

05/14/84

6,942

Pumping

UE-25 c#3

26.1

Drawdown

13

1.7

2,200

0.004

0.07

Neuman (1975)

Geldon (1996)

06/12/95

06/16/95

5,803

Pumping

UE-25 c#3

22.5

Drawdown

0.12

0.003

5.5

0.0002

0.02

Neuman (1975)

Geldon et al. (2002)

06/12/95

06/16/95

5,803

Pumping

UE-25 c#3

22.5

Drawdown

1.7

ND

40

0.0004

ND

Theis (1935)

Geldon et al. (2002)

06/12/95

06/16/95

5,803

Pumping

UE-25 c#3

22.5

Drawdown

4.2

ND

100

0.00003

ND

Theis (1935)

Geldon et al. (2002)

05/08/96

03/26/97

464,100

Pumping

UE-25 c#3

9.53

Drawdown

40

ND

1,300

0.02

ND

Streltsova-Adams Geldon et al. (2002) (1978)

02/08/96

02/13/96

6,984

Pumping

UE-25 c#3

8.49

Drawdown

28

ND

600

0.0008

ND

Theis (1935)

Graves (1998, 2000); Geldon (1999, 2000)

Geldon et al. (2002)

80

A.L. Geldon

Observation well

UTM east coordinate (m)

UTM north coordinate (m)

Altitude (m AMSL)

Well depth (m)

Top (m)

Bottom (m)

SWL (m below LSD)

Radius or interwell distance (m)

UE-25 c#3

550,919.81

4,075,885.91

1,132.4

907.1

542.2

609.9

401.9

28.7

Prow Pass Tuff

Fractured, partly argillized to zeolitized, NWMW ash-flow tuff

UE-25 ONC #1

550,471.81

4,076,599.63

1,162.8

469.4

451.7

469.4

433.2

851.3

Prow Pass Tuff

Vitric, NW ash-flow tuff

UE-25 ONC #1

550,471.81

4,076,599.63

1,162.8

469.4

453.2

469.4

433.2

842.8

Prow Pass and Bullfrog Tuffs

Faulted, variably fractured, argillized, and zeolitized, NW-DW ash-flow tuff

UE-25 ONC #1

550,471.81

4,076,599.63

1,162.8

469.4

453.2

469.4

433.3

842.8

Prow Pass, Bullfrog, and Tram Tuffs

Faulted, variably fractured, argillized, and zeolitized, NW-DW ash-flow tuff and bedded tuff

UE-25 p#1

551,508.58

4,075,662.87

1,114.2

1,805.3

469

500

382

0.18

Prow Pass Tuff

Partly zeolitized, PW ash-flow tuff

UE-25 p#1

551,508.58

4,075,662.87

1,114.2

1,805.3

564

616

382

0.16

Bullfrog Tuff

NW-MW ash-flow tuff

UE-25 p#1

551,508.58

4,075,662.87

1,114.2

1,805.3

764

834

383

0.15

Tram Tuff

PW ash-flow tuff

UE-25 p#1

551,508.58

4,075,662.87

1,114.2

1,805.3

904

1,067

382

0.15

Lithic Ridge Tuff

Zeolitized, NW-PW ash-flow tuff and bedded tuff

USW G-2

548,138.53

4,082,553.89

1,533.9

1,830.6

534.0

792.0

534.0

0.13

Calico Hills Formation

Faulted, fractured, zeolitized, NW ash-flow tuff with thin bedded tuff intervals

USW G-4

548,937.85

4,078,590.13

1,269.6

914.7

616

655

541.5

0.12

Prow Pass Tuff

Faulted(?), zeolitized, NW-PW ash-flow tuff

USW G-4

548,937.85

4,078,590.13

1,269.6

914.7

698

826

541.7

0.13

Bullfrog Tuff

Fractured, zeolitized to argillized, NW-DW ash-flow tuff

USW G-4

548,937.85

4,078,590.13

1,269.6

914.7

541.1

914.7

541.1

0.13

Tram Tuff

Fractured, NW-MW ash-fow tuff

USW H-1

548,721.75

4,079,944.54

1,303.1

1,828.8

572

765

572.2

4,625

Prow Pass and Bullfrog Tuffs

Faulted, fractured, partly zeolitized, NW-PW ash-flow tuff

Geologic Unit

Lithologic description

USW H-1

548,721.75

4,079,944.54

1,303.0

1,828.8

572.3

687.9

572.3

0.13

Prow Pass Tuff

Faulted, fractured, PW ash-flow tuff

USW H-1

548,721.75

4,079,944.54

1,303.0

1,828.8

687.3

707

572.5

0.11

Prow Pass Tuff

Fractured, zeolitized, NW ash-flow tuff

USW H-1

548,721.75

4,079,944.54

1,303.0

1,828.8

707

832

572.7

0.11

Bullfrog Tuff

Fractured, partly zeolitized, NW-PW ash-flow tuff

USW H-3

547,536.88

4,075,762.03

1,483.2

1,219.2

809

1,108.3

750.8

0.12

Tram Tuff

Locally fractured, partly zeolitized, PW-MW ash-flow tuff and fractured, zeolitized, bedded tuff

USW H-3

547,536.88

4,075,762.03

1,483.2

1,219.2

1,108.3

1,219.2

750.6

0.12

Lithic Ridge Tuff

Zeolitized, argillized, PW ash-flow tuff

USW H-4

549,195.04

4,077,322.35

1,248.7

1,219.2

560.5

1,181.1

518.4

2,245

Prow Pass and Bullfrog Tuffs

Faulted, variably fractured, partly zeolitized, NW-DW ash-flow tuff and bedded tuff

USW H-4

549,195.04

4,077,322.35

1,248.7

1,219.2

518.4

1,181.1

518.4

2,245

Prow Pass, Bullfrog, and Tram Tuffs

Faulted, variably fractured, partly zeolitized, NW-DW ash-flow tuff and bedded tuff

USW H-5

547,665.33

4,078,837.70

1,478.9

1,219.2

704.4

835.8

704.6

0.16

Bullfrog Tuff

NW-DW ash-flow tuff

USW H-5

547,665.33

4,078,837.70

1,478.9

1,219.2

835.8

1,043.0

704.8

0.11

Tram Tuff

Zeolitized, PW, ash-flow tuff

USW H-6

546,196.05

4,077,816.27

1,302.1

1,219.9

547.1

687.3

526.0

0.11

Bullfrog Tuff

Fractured, PW-MW ash-flow tuff

USW H-6

546,196.05

4,077,816.27

1,302.1

1,219.9

687.3

877.2

526.5

0.11

Tram Tuff

Fractured, PW ash-flow tuff

USW H-6

546,196.05

4,077,816.27

1,302.1

1,219.9

753

834

526.5

0.11

Tram Tuff

Fractured, PW ash-flow tuff

NC-EWDP-3D

541,273.79

4,059,456.99

798.3

762.0

121.0

762.0

78.9

0.11

Tram and Lithic Ridge Tuffs

NW ash-flow tuff

UE-25 c#2, USW-H4, UE-25 ONC#1

Variable

Variable

Variable

Variable

Variable

Variable

Variable

29-2,245

Calico Hills Formation to Tram Tuff

Faulted, variably fractured and altered, NWDW ash-flow tuff, tuff breccia, and bedded tuff

UE-25 c#1, UE-25 c#2, UE-25 WT#3, UE-25 WT#14, UE25 ONC#1, USW H-4

Variable

Variable

Variable

Variable

Variable

Variable

Variable

29-3,526

Topopah Spring Tuff to Bullfrog Tuff

Faulted, variably fractured, zeolitized, and argillized NW-DW ash-flow tuff, tuff breccia, and bedded tuff

UE-25 c#1, c#2, b#1, WT#3, WT#4, WT#14, ONC#1; USW H-1, H-4, WT-1, WT-11

Variable

Variable

Variable

Variable

Variable

Variable

Variable

29-6,414

Topopah Spring Tuff to Bullfrog Tuff

Faulted, variably fractured, zeolitized, and argillized NW-DW ash-flow tuff, bedded tuff, and rhyolite lava

UE-25 c#1, UE-25 c#2, UE-25 ONC#1, UE-25 WT#3

Variable

Variable

Variable

Variable

Variable

Variable

Variable

29-3,526

Prow Pass and Bullfrog Tuffs

Faulted, variably fractured, zeolitized, and argillized NW-DW ash-flow tuff and bedded tuff

OLDER TERTIARY TUFF AND LAVA FLOWS UE-25 p#1

551,508.58

4,075,662.87

1,114.2

1,805.3

1,067

1,114

382

0.14

Unit A of USW G-1 and Rhyolite of Picture Rock

Argillized, NW-PW ash-flow tuff

Test Well 8

563,111.75

4,113,271.15

1,735.7

1,673.4

325.1

619.0

325.1

0.15

Comendite of Quartet Dome

Comendite lava flows and partly zeolitized, NW-MW ash-flow tuff

Implications for groundwater flow in the Southwest Nevada Volcanic Field

Test start

Test end

Test length (min)

Test type

Production well

Discharge or injection rate (L/s)

Analyzed Data

Kr (m/d)

Kz (m/d)

T (m2/d)

Storativity

Specific yield

06/02/98

06/11/98

12,500

Pumping

UE-25 c#2

0.33

Drawdown

0.55

ND

17

0.00005

06/11/98

09/01/98

118,159

Injection

UE-25 c#3

0.095

Head rise

1.6

ND

30

05/08/96

11/12/97

796,663

Pumping

UE-25 c#3

9.21

Drawdown

11

ND

05/22/95

06/01/95

14,403

Pumping

UE-25 c#3

17.9

Drawdown

16

02/07/83

02/09/83

3,150

Pumping

Same

22.1

Drawdown

02/07/83

02/09/83

3,150

Pumping

Same

22.1

Feb-83

Feb-83

170

Slug-injection

Same

02/07/83

02/09/83

3,150

Pumping

04/08/96

04/25/96

24,480

01/07/83

01/07/83

01/08/83

81

Analyical method

Sources of hydraulicproperty data, test analyses, and supporting information

ND

Cooper (1963)*

Geldon et al. (1999)

0.002

ND

Streltsova-Adams Geldon et al. (1999) (1978)

970

0.01

ND

Streltsova-Adams Geldon et al. (2002) (1978)

ND

2,900

0.003

ND

Theis (1935)

0.55

ND

17

ND

ND

Streltsova-Adams Craig and Robison (1978)* (1984)

Drawdown

0.022

ND

0.84

ND

ND

Streltsova-Adams Craig and Robison (1978)* (1984)

NA

Recovery

0.0083

ND

0.58

ND

ND

Cooper et al. (1967)

Same

22.1

Drawdown

0.015

ND

2.0

ND

ND

Streltsova-Adams Craig and Robison (1978)* (1984)

Pumping

Same

3.60

Drawdown

0.044

ND

11

ND

ND

Theis (1935)*

O’Brien (1998)

60

Slug-injection

Same

NA

Recovery

0.029

ND

1.2

ND

ND

Cooper et al. (1967)

Lobmeyer (1986)

01/11/83

60-200

Slug-injection

Same

NA

Recovery

0.021

ND

2.7

ND

ND

Cooper et al. (1967)

Lobmeyer (1986)

12/05/82

12/09/82

5,740

Pumping

Same

15.7

Drawdown

1.7

ND

110

ND

ND

Neuman (1975)* Bentley (1984); Lobmeyer (1986)

05/08/96

08/06/97

655,242

Pumping

UE-25 c#3

9.29

Drawdown

6.3

ND

650

0.001

ND

Cooper and Jacob (1946)*

Graves (1998, 2000); Geldon (1999, 2000)

10/19/80

10/20/80

2,880

Pumping

Same

3.48

Drawdown

1.9

ND

150

ND

ND

Theis (1935)

Rush et al. (1983, 1984)

12/06/80

12/08/80

3,383

Pumping

Same

2.26

Drawdown

0.020

ND

0.14

ND

ND

Theis (1935)

Rush et al. (1983, 1984)

12/06/80

12/08/80

3,383

Pumping

Same

2.26

Drawdown

0.038

ND

0.84

ND

ND

Theis (1935)

Rush et al. (1983, 1984)

Jan-84

Jan-84

20,520

Pumping

Same

0.16

Drawdown

0.0074

ND

0.92

ND

ND

Theis (1935)

Thordarson et al. (1985)

Geldon et al. (2002)

Craig and Robison (1984)

Jan-84

Jan-84

20,520

Pumping

Same

0.16

Drawdown

0.015

ND

0.084

ND

ND

Theis (1935)

Thordarson et al. (1985)

05/08/96

12/02/96

300,000

Pumping

UE-25 c#3

9.59

Drawdown

5.0

ND

560

0.002

ND

Walton (1970)*

Whitfield et al. (1985); Geldon et al. (2002)

05/22/95

06/01/95

14,403

Pumping

UE-25 c#3

17.9

Drawdown

17

ND

3,200

0.002

ND

Theis (1935)

Whitfield et al. (1985); Geldon et al. (1998)

07/25/82

07/26/82

1,756

Pumping

Same

7.6

Drawdown

0.39

ND

35

ND

ND

Neuman (1975)* Bentley et al. (1983); Robison and Craig (1991)

07/25/82

07/26/82

1,756

Pumping

Same

7.6

Drawdown

0.12

ND

3.5

ND

ND

Neuman (1975)* Bentley et al. (1983); Robison and Craig (1991)

10/10/82

10/13/82

4,184

Pumping

Same

28.4

Drawdown

0.25

ND

12

ND

ND

Neuman (1975)* Craig and Reed (1991)

10/10/82

10/13/82

4,184

Pumping

Same

28.4

Drawdown

0.52

ND

5.7

ND

ND

Neuman (1975)* Craig and Reed (1991)

Jun-84

Jun-84

15,540

Pumping

Same

13.4

Drawdown

0.30

ND

3.3

ND

ND

Cooper (1963)*

02/18/99

02/20/99

3,030

Pumping

Same

10.7

Drawdown

0.49

ND

82

ND

ND

Streltsova-Adams Questa Engineering (1978)* Corp. (1999)

05/22/95

06/01/95

14,000

Pumping

UE-25 c#3

17.9

Drawdown

14

ND

2,500

0.002

ND

Neuman (1975)* Geldon et al. (1998)

05/08/96

05/29/96

30,000

Pumping

UE-25 c#3

9.72

Drawdown

26

ND

2,600

0.0005

ND

Cooper and Jacob (1946)

Geldon et al. (2002)

05/08/96

06/26/96

70,000

Pumping

UE-25 c#3

9.72

Drawdown

24

ND

2,400

0.0006

ND

Cooper and Jacob (1946)*

Graves (1998, 2000); Geldon (1999, 2000)

05/08/96

03/26/97

464,100

Pumping

UE-25 c#3

9.53

Drawdown

22

ND

2,200

0.002

ND

Theis (1935)

Geldon et al. (2002)

02/07/83

02/09/83

120 - 3,150

Pumping

Same

Variable

Drawdown

0.023

ND

1.1

ND

ND

Streltsova-Adams Craig and Robison (1978)* (1984)

01/10/63

01/11/63

2,100

Pumping

Same

25.2

Drawdown

1.9

ND

410

ND

ND

Neuman (1975)* West and Thordarson (1963); Winograd (1965)

Craig and Reed (1991)

82

A.L. Geldon

Observation well

UTM east coordinate (m)

UTM north coordinate (m)

Altitude (m AMSL)

Well depth (m)

Top (m)

Bottom (m)

SWL (m below LSD)

Radius or interwell distance (m)

Test Well 8

563,111.75

4,113,271.15

1,735.7

1,673.4

619.0

1,673.4

325.1

0.097

Tuff of Yucca Flat to Tuff of Twin Peaks PW-DW ash-flow tuff and zeolitized bedded tuff

UE-20f

545,389.67

4,124,898.04

1,864.3

4,171.5

3,011.1

3,378.7

541.5

0.11

Rhyolite of Handley

Rhyolite flow breccia

UE-20f

545,389.67

4,124,898.04

1,864.3

4,171.5

3,707.6

3,879.2

541.5

0.11

Dacite of Mt. Helen (?)

Rhyodacite lava flow

UE-20j

541,285.59

4,128,081.76

1,799.2

1,734.3

1,107.6

1,168.0

387.2

0.13

Rhyolite of Handley

Rhyolite flow breccia

Test Well E

589,358.97

4,101,335.13

1,271.6

600.5

523.2

600.5

523.2

0.15

Tunnel Fm, Tunnel bed 2, and Tuff of Yucca Flat

Zeolitized, NW ash-flow tuff and bedded tuff

Test Well E

589,358.97

4,101,335.13

1,271.6

600.5

546.2

600.5

523.2

0.15

Tuff of Yucca Flat

Zeolitized, NW ash-flow tuff

U-3cn 5

586,921.42

4,101,713.19

1,222.9

923.5

559.9

603.5

508.7

0.16

Tuff of Yucca Flat

Fractured, PW ash-flow tuff

U-3cn 5

586,921.42

4,101,713.19

1,222.9

923.5

603.5

654.7

508.1

0.13

Tuff of Yucca Flat to Redrock Valley Tuff

Very fractured, partly zeolitized, NW-MW ashflow tuff and bedded tuff

U-3cn 5

586,921.42

4,101,713.19

1,222.9

923.5

670.6

726.9

502.9

0.13

Redrock Valley Tuff and Tuff of Twin Peaks

Partly zeolitized, NW-MW ash-flow tuff

Test Well 2

581,016.62

4,113,486.03

1,362.5

623.3

587.5

623.3

587.5

0.14

Tuff of Yucca Flat to Redrock Valley Tuff

Zeolitized and argillized, NW ash-flow tuff

Test Well 2

581,016.62

4,113,486.03

1,362.5

723.3

646.5

723.3

ND

0.14

Redrock Valley Tuff and Tuff of Twin Peaks

Zeolitized and argillized, NW ash-flow tuff

Watertown 1 WW

605,595.53

4,122,450.17

1,353.6

204.2

171.0

204.2

150.0

0.10

Volcanic rocks of the Groom Range and Jumbled Hills

DW ash-flow tuff and zeolitized bedded tuff

HTH-1

568,543.15

4,275,398.56

1,832.1

1,126.2

731.7

750.0

166.8

0.12

Monotony Tuff

DW ash-flow tuff

HTH-3

576,919.94

4,267,658.04

1,802.7

1,831.5

1,056.1

1,171.0

169.8

0.12

Tuff of Williams Ridge and Morey Peak Argillized, PW-DW ash-flow tuff

HTH-3

576,919.94

4,267,658.04

1,802.7

1,831.5

1,431.6

1,831.5

172.6

0.11

Tuff of Williams Ridge and Morey Peak Argillized, PW-DW ash-flow tuff and volcaniclastic rocks

HTH-4

584,897.68

4,265,713.88

1,776.3

1,839.7

265.2

271.3

151.1

0.17

Tuff of Palisade Mesa (?)

DW ash-flow tuff

HTH-4

584,897.68

4,265,713.88

1,776.3

1,839.7

615.7

1,792.2

159.5

0.070

Tuffs of Halligan Mesa and Williams Ridge and Morey Peak

NW-DW ash-flow tuff

HTH-21-1

580,377.29

4,271,115.80

1,786.8

1,981.1

694.6

706.5

151.6

0.12

Tuff of Lunar Cuesta

NW-PW ash-flow tuff

HTH-21-1

580,377.29

4,271,115.80

1,786.8

1,981.1

709.5

749.2

151.6

0.12

Shingle Pass Tuff

NW-DW ash-flow tuff

HTH-21-1

580,377.29

4,271,115.80

1,786.8

1,981.1

1,109.4

1,167.3

152.4

0.12

Monotony Tuff

DW ash-flow tuff

HTH-21-1

580,377.29

4,271,115.80

1,786.8

1,981.1

1,534.6

1,592.5

151.6

0.12

Oligocene felsic lava flows

Rhyolite to rhyodacite lava flows

HTH-21-1

580,377.29

4,271,115.80

1,786.8

1,981.1

1,737.4

1,828.8

152.4

0.12

Tuff of Williams Ridge and Morey Peak PW-DW ash-flow tuff

HTH-23

585,203.09

4,262,246.59

1,766.3

2,285.9

1,377.7

1,891.3

144.0

0.086

Tuff of Williams Ridge and Morey Peak PW-DW ash-flow tuff

HTH-23

585,203.09

4,262,246.59

1,766.3

2,285.9

1,911.0

1,943.9

136.6

0.086

Tuff of Williams Ridge and Morey Peak PW-DW ash-flow tuff

UCe-2

536,397.50

4,239,403.72

1,889.8

505.7

247.5

369.4

ND

0.078

Tuff of Kiln Canyon

Fractured, argillized, PW-DW ash-flow tuff

UCe-2

536,397.50

4,239,403.72

1,889.8

505.7

396.3

505.7

ND

0.078

Tuff of Big Ten Peak

Fractured, argillized, PW ash-flow tuff

UCe-3

531,589.22

4,313,188.33

2,164.1

609.6

72.2

121.9

72.2

0.081

Shingle Pass Tuff

Argillized, PW-DW ash-flow tuff

UCe-3

531,589.22

4,313,188.33

2,164.1

609.6

399.3

453.5

72.2

0.088

Oligocene mafic lava flows

Variably argillized andesite lava flows

UCe-3

531,589.22

4,313,188.33

2,164.1

609.6

454.8

609.6

72.6

0.085

Oligocene mafic lava flows

Variably argillized andesite lava flows with gravelly sandstone

UCe-16

523,254.09

4,302,423.31

2,095.5

1,326.8

1,022.9

1,138.1

15.8

0.15

Oligocene felsic lava flows

Argillized rhyolite lava flows

UCe-17

568,049.79

4,281,240.26

1,995.4

2,431.7

957.0

1,018.0

269

0.15

Tuff of Moores Station Buttes and unnamed tuff

Bedded tuff and DW ash-flow tuff

UCe-17

568,049.79

4,281,240.26

1,995.4

2,431.7

1,367.7

1,469.5

272

0.13

Tuffaceous rocks of the Needles area

DW ash-flow tuff

Geologic Unit

Lithologic description

Implications for groundwater flow in the Southwest Nevada Volcanic Field

Test start

Test end

Test length (min)

Test type

Production well

Discharge or injection rate (L/s)

Analyzed Data

Kr (m/d)

Kz (m/d)

T (m2/d)

Storativity

Specific yield

01/04/63

01/05/63

1,855

Pumping

Same

4.86

Drawdown

0.068

ND

4.5

ND

08/09/64

08/11/64

2,800

Pumping

Same

6.92

Drawdown

0.014

ND

0.096

08/09/64

08/11/64

2,800

Pumping

Same

6.92

Drawdown

0.0012

ND

Oct-64

Oct-64

10

Slug-injection

Same

NA

Recovery

0.054

08/02/60

08/07/60

6,460

Bailingrecovery

Same

0.74

Residual drawdown

10/02/60

10/03/60

1,208

Bailingrecovery

Same

0.45

01/03/66

01/05/66

2,990

Swabbingrecovery

Same

01/01/66

01/03/66

3,090

Swabbingrecovery

12/19/65

12/22/65

4,080

03/24/61

03/25/61

05/30/61

83

Analyical method

Sources of hydraulicproperty data, test analyses, and supporting information

ND

Theis (1935)

West and Thordarson (1963); IT Corporation (1996)

ND

ND

Hantush (1961)* Blankennagel et al. (1964); Blankennagel and Weir (1965)

0.036

ND

ND

Hantush (1961)* Blankennagel et al. (1964); Blankennagel and Weir (1965)

ND

3.3

ND

ND

Cooper et al. (1967)

Blankennagel and Weir (1966)

0.00052

ND

0.040

ND

ND

Theis (1935) recovery*

West and Thordarson (1965)

Residual drawdown

0.0013

ND

0.070

ND

ND

Theis (1935) recovery *

West and Thordarson (1965)

NA

Recovery

0.0084

ND

0.37

ND

ND

Theis (1935) recovery *

Garber and Johnston (1967)

Same

NA

Recovery

0.016

ND

0.83

ND

ND

Theis (1935) recovery *

Garber and Johnston (1967)

Swabbingrecovery

Same

NA

Recovery

0.0017

ND

0.095

ND

ND

Theis (1935) recovery *

Garber and Johnston (1967)

1,107

Bailingrecovery

Same

1.32

Residual drawdown

0.0036

ND

0.13

ND

ND

Theis (1935) recovery *

Moore et al. (1963)

05/30/61

217

Bailingrecovery

Same

0.31

Residual drawdown

0.0043

ND

0.10

ND

ND

Theis (1935) recovery *

Moore et al. (1963)

06/24/55

06/24/55

720

Pumping

Same

1.4

Drawdown

0.080

ND

2.7

ND

ND

Cooper (1963)

IT Corporation (1996)

08/01/67

08/01/67

100

Slug-injection

Same

NA

Recovery

0.018

ND

0.33

ND

ND

Cooper et al. (1967)

Dinwiddie (1968, 1970a)

08/27/68

08/30/68

80-380

Slug-injection

Same

NA

Recovery

0.10

ND

12

ND

ND

Cooper et al. (1967)

Dinwiddie (1970b)

10/26/68

10/28/68

2,584

Pumping

Same

1.58

Drawdown

0.0019

ND

0.18

ND

ND

Neuman (1975)* Dinwiddie (1970b)

01/21/69

01/21/69

325

Slug-injection

Same

NA

Recovery

0.12

ND

0.73

ND

ND

Cooper et al. (1967)

Dinwiddie (1970c)

02/04/69

02/04/69

445

Injection

Same

3.15

Residual head rise

0.40

ND

18

ND

ND

Theis (1935)*

Dinwiddie (1970c)

08/21/68

08/22/68

1,700

Pumping

Same

15.1

Drawdown

6.5

ND

78

ND

ND

Theis (1935)*

Dinwiddie and Schroder (1971)

08/21/68

08/22/68

1,700

Pumping

Same

15.1

Drawdown

0.59

ND

23

ND

ND

Theis (1935)*

Dinwiddie and Schroder (1971)

08/21/68

08/22/68

1,700

Pumping

Same

15.1

Drawdown

0.72

ND

42

ND

ND

Theis (1935)*

Dinwiddie and Schroder (1971)

08/21/68

08/22/68

1,700

Pumping

Same

15.1

Drawdown

0.58

ND

33

ND

ND

Theis (1935)*

Dinwiddie and Schroder (1971)

08/21/68

08/22/68

1,700

Pumping

Same

15.1

Drawdown

0.051

ND

4.5

ND

ND

Theis (1935)*

Dinwiddie (1970d); Dinwiddie and Schroder (1971)

11/22/68

11/22/68

912

Pumping

Same

1.01

Drawdown

0.0049

ND

1.1

ND

ND

Cooper (1963)*

Dinwiddie (1970e); Dinwiddie and Schroder (1971)

12/16/68

12/16/68

150

Slug-injection

Same

NA

Recovery

0.15

ND

4.8

ND

ND

Cooper et al. (1967)

Dinwiddie (1970e); Dinwiddie and Schroder (1971)

01/16/67

01/16/67

4.5-150

Slug-injection

Same

NA

Recovery

0.067

ND

7.9

ND

ND

Cooper et al. (1967)*

Dinwiddie (1970f)

01/21/67

01/21/67

26-90

Slug-injection; swabbingrecovery

Same

Variable

Recovery; residual drawdown

0.57

ND

63

ND

ND

Theis (1935); Cooper et al. (1967)*

Dinwiddie (1970f)

02/19/67

02/19/67

180

Swabbingrecovery

Same

0.16

Residual drawdown

0.0064

ND

0.32

ND

ND

Theis (1935) recovery *

Dinwiddie (1970g)

02/15/67

02/15/67

200

Slug-injection

Same

NA

Recovery

0.0094

ND

0.51

ND

ND

Cooper et al. (1967)*

Dinwiddie (1970g)

02/11/67

02/12/67

1,980

Swabbingrecovery

Same

0.48

Residual drawdown

0.0027

ND

0.23

ND

ND

Theis (1935)*

Dinwiddie (1970g)

03/27/67

03/27/67

1,010

Swabbingrecovery

Same

0.091

Residual drawdown

0.000013

ND

0.0015

ND

ND

Theis (1935) recovery *

Dinwiddie and Schroder (1971)

06/25/67

06/25/67

30

Slug-injection

Same

NA

Recovery

0.0029

ND

0.18

ND

ND

Cooper et al. (1967)*

Dinwiddie (1968, 1970a)

06/24/67

06/25/67

45-60

Slug-injection

Same

NA

Recovery

0.087

ND

8.9

ND

ND

Cooper et al. (1967)*

Dinwiddie (1968, 1970a)

84

A.L. Geldon

Observation well

UTM east coordinate (m)

UTM north coordinate (m)

Altitude (m AMSL)

Well depth (m)

Top (m)

Bottom (m)

SWL (m below LSD)

Radius or interwell distance (m)

UCe-17

568,049.79

4,281,240.26

1,995.4

2,431.7

1,960.4

2,273.5

ND

0.12

Tuff of Hot Creek Canyon (?)

PW-DW ash-flow tuff

UCe-18

570,423.78

4,270,952.61

1,756.6

1,985.5

123.7

1,865.4

56.0

0.12

Oligocene felsic lava flows

Fractured, argillized rhyolite lava flows and flow breccias

Uce-20

568,069.77

4,271,868.87

1,755.3

1,829.3

1,481.4

1,617.7

ND

0.14

Tuff of Moores Station Buttes

Slightly fractured to brecciated, PW-DW ash-flow tuff

Uce-20

568,069.77

4,271,868.87

1,755.3

1,829.3

1,652.4

1,670.7

65.5

0.12

Tuff of Moores Station Buttes

Bedded tuff

Uce-20

568,069.77

4,271,868.87

1,755.3

1,829.3

1,680.0

1,829.3

82.9

0.13

Tuffaceous rocks of the Needles area

NW-DW ash-flow tuff

Adobe Federal 16-1

601,489.88

4,238,938.44

1,447.5

1,202.4

380.4

409.0

ND

0.089

Garrett Ranch Group

Lava flows, NW-DW ash-flow tuff, ash-fall tuff, and sandstone

Geologic Unit

Lithologic description

TERTIARY AND MESOZOIC GRANITIC ROCKS U-15-32

583,748.77

4,120,261.94

1,547.2

276.4

129.1

276.4

129.1

0.11

Climax Stock

Fractured quartz monzonite porphyry and granodiorite

U-15-GZ-2

583,917.75

4,120,387.47

1,549.9

548.6

132.4

548.6

132.4

0.078

Climax Stock

Fractured quartz monzonite porphyry and granodiorite

U-15-35

583,561.96

4,119,745.99

1,518.2

246.0

27.7

246.0

27.7

0.076

Climax Stock

Fractured quartz monzonite porphyry and granodiorite

U-15a-31

583,441.23

4,120,197.49

1,558.1

365.8

310.9

319.1

310.9

0.044

Climax Stock

Fractured, argillized, and chloritized granodiorite

UCe-1

507,521.34

4,270,166.68

2,148.8

609.6

121.9

182.3

64.5

0.12

Belmont Stock

Fractured, partly argillized granite, granodiorite, and quartz monzonite

UCe-1

507,521.34

4,270,166.68

2,148.8

609.6

459.6

520.0

65.1

0.12

Belmont Stock

Fractured, partly argillized granite, granodiorite, and quartz monzonite

UCe-1

507,521.34

4,270,166.68

2,148.8

609.6

521.2

609.6

65.1

0.12

Belmont Stock

Fractured, partly argillized granite, granodiorite, and quartz monzonite

17S/2E-6F11

517335.89

3,620,537.35

498.4

13.9

11.9

24.1

11.0

10.0

Peninsular Ranges batholith

Fractured, weathered granodiorite

17S/2E-6F12

ND

ND

499.7

17.1

11.9

24.1

9.4

19.2

Peninsular Ranges batholith

Fractured, weathered granodiorite

17S/2E-7C6

ND

ND

460.7

7.2

3.0

12.2

3.0

7.4

Peninsular Ranges batholith

Fractured, weathered granodiorite

17S/2E-5N7

ND

ND

505.9

100.0

23.5

33.5

23.1

8.9

Peninsular Ranges batholith

Fractured, weathered granodiorite

17S/2E-6R3

ND

ND

502.9

48.5

11.6

24.4

11.5

9.4

Peninsular Ranges batholith

Fractured, weathered granodiorite

16S/2E-31N6

ND

ND

527.5

94.8

14.0

27.4

13.0

9.4

Peninsular Ranges batholith

Fractured, weathered granodiorite

17S/2E-6R3

ND

ND

502.9

48.5

24.4

61.0

11.5

9.4

Peninsular Ranges batholith

Fractured granodiorite

17S/2E-6F14

ND

ND

498.9

57.6

24.7

60.4

7.2

29.4

Peninsular Ranges batholith

Fractured granodiorite

1,152.1

21.3

2.4

21.3

2.4

0.15

Chinle Formation

Gravelly sandstone and conglomerate Limestone, sandstone, anhydrite

MESOZOIC AND PERMIAN SEDIMENTARY ROCKS Spring Mt. Ranch well

639,459.71

3,992,498.52

Virgin River USA 1-A

726,738.60

4,279,652.11

580.6

5,962.5

3,585.7

3,600.9

ND

0.049

Toroweap Formation

Upper Valley Unit #11

433,230.91

4,167,664.42

2,289.0

2,171.7

2,114.1

2,127.5

ND

0.049

Kaibab Formation

Cherty dolomite

Lyons Federal #1

446,879.08

4,152,310.18

2,045.2

2,526.8

2,224.4

2,234.2

ND

0.049

Kaibab Formation

Cherty dolomite

Federal #28-13

496,434.20

4,137,594.88

1,429.8

942.4

835.5

840.3

ND

0.049

Kaibab Formation

Sandy dolomite

Tibbet Canyon #1

435,443.92

4,130,694.19

1,874.8

2,845.6

2,473.5

2,481.7

ND

0.049

Kaibab Formation

Cherty dolomite

A J Button #1

447,080.12

4,176,131.78

1,758.1

1,671.2

1,519.4

1,528.6

ND

0.049

Toroweap Formation

Sandstone and dolomite

Woolsey #1

449,538.43

4,169,736.78

1,766.9

1,780.0

1,614.5

1,621.5

ND

0.049

Toroweap Formation

Sandstone, dolomite, and anhydrite

Richter Federal #1

487,947.97

4,135,631.11

1,461.5

ND

955.2

967.1

ND

0.049

Toroweap Formation

Sandstone and dolomite

Kanab Creek Unit #1

ND

ND

1,879.1

2,779.5

1,399.0

1,403.3

ND

0.049

Toroweap Formation

Sandstone and dolomite

Taylor Canyon #1

ND

ND

1,219.2

152.4

113.7

152.4

ND

ND

White Rim Sandstone

Quartz sandstone

Taylor Canyon #3

591,738.93

4,258,805.40

1,271.0

178.3

128.0

178.3

ND

ND

White Rim Sandstone

Quartz sandstone

Taylor Canyon #2

594,331.52

4,258,835.43

1,292.4

178.3

140.5

178.3

ND

ND

White Rim Sandstone

Quartz sandstone

Blue Mesa #1

512,408.36

4,238,560.67

1,472.2

2,491.4

1,555.1

1,572.5

ND

0.049

White Rim Sandstone

Quartz sandstone

Johns Valley Federal #1

ND

ND

2,466.7

3,407.7

2,791.4

2,801.4

ND

0.049

White Rim Sandstone

Quartzitic sandstone

Bryce #1

ND

ND

2,352.4

3,420.2

3,390.0

3,420.2

ND

0.049

White Rim Sandstone

Sandstone, siltstone, and anhydrite

Upper Valley Unit #21

435,102.43

4,162,656.69

2,208.6

3,033.1

2,392.7

2,427.4

ND

0.049

White Rim Sandstone

Calcareous sandstone

Rees Canyon #1

465,141.59

4,134,338.64

1,900.1

ND

1,986.1

1,993.4

ND

0.049

White Rim Sandstone

Dolomitic sandstone

Implications for groundwater flow in the Southwest Nevada Volcanic Field

Test start

Test end

Test length (min)

Test type

Production well

Discharge or injection rate (L/s)

Analyzed Data

Kr (m/d)

Kz (m/d)

T (m2/d)

Storativity

Specific yield

06/21/67

06/23/67

105-430

Slug-injection

Same

NA

Recovery

0.00038

ND

0.093

ND

06/14/67

06/14/67

721

Pumping

Same

10.6

Residual drawdown

0.11

ND

26

12/19/67

12/20/67

100

Slug-injection

Same

NA

Recovery

0.00099

ND

01/05/68

01/05/68

2.5

Slug-injection

Same

NA

Recovery

1.1

01/03/68

01/03/68

6

Slug-injection

Same

NA

Recovery

Oct-82

Oct-82

90

Drill-stem

Same

ND

85

Analyical method

Sources of hydraulicproperty data, test analyses, and supporting information

ND

Cooper et al. (1967)

Dinwiddie (1968, 1970a)

ND

ND

Theis (1935) recovery *

Dinwiddie and Schroder (1971)

0.14

ND

ND

Cooper et al. (1967)

Dinwiddie and Schroder (1971)

ND

20

ND

ND

Cooper et al. (1967)*

Dinwiddie and Schroder (1971)

0.13

ND

13

ND

ND

Cooper et al. (1967)*

Dinwiddie and Schroder (1971)

Recovery

0.0082

ND

0.24

ND

ND

Horner (1951)

McKay and Kepper (1988) Walker (1962)

TERTIARY AND MESOZOIC GRANITIC ROCKS 12/16/60

12/16/60

90

Slugwithdrawal

Same

NA

Residual drawdown

0.18

ND

26

ND

ND

Cooper et al. (1967)*

02/06/61

02/06/61

140

Slugwithdrawal

Same

NA

Residual drawdown

0.018

ND

7.4

ND

ND

Skibitzke (1963)* Walker (1962)

08/26/60

08/26/60

97

Injection

Same

3.8

Residual head rise

0.0033

ND

0.71

ND

ND

Theis (1935) recovery *

Walker (1962)

04/29/59

04/29/59

165

Slug-injection

Same

NA

Residual head rise

0.051

ND

0.42

ND

ND

Cooper et al. (1967)*

Price (1960); Houser and Poole (1959)

02/12/67

02/13/67

1,020

Swabbingrecovery

Same

0.25

Residual drawdown

0.017

ND

1.1

ND

ND

Theis (1935) recovery *

Dinwiddie (1970h)

02/01/67

02/02/67

450

Swabbingrecovery

Same

0.29

Residual drawdown

0.00056

ND

0.034

ND

ND

Theis (1935) recovery *

Dinwiddie (1970h)

02/01/67

02/01/67

255

Swabbingrecovery

Same

0.65

Residual drawdown

0.00077

ND

0.068

ND

ND

Theis (1935) recovery *

Dinwiddie (1970h)

01/10/88

01/11/88

1,200

Pumping

17S/2E-6F9

0.15

Drawdown

0.067

0.018

0.82

0.00007

ND

Kaehler and Hsieh (1994)

Kaehler and Hsieh (1994)

01/10/88

01/11/88

1,200

Pumping

17S/2E-6F9

0.15

Drawdown

0.067

0.011

0.82

0.00004

ND

Kaehler and Hsieh (1994)

Kaehler and Hsieh (1994)

12/08/87

12/08/87

400

Pumping

17S/2E-7C1

0.13

Drawdown

0.73

0.020

6.7

0.0002

ND

Neuman (1972, 1973, 1974)

Kaehler and Hsieh (1994)

12/13/87

12/13/87

420

Pumping

17S/2E-5N5

0.12

Drawdown

0.49

0.52

4.7

0.001

0.002

Neuman (1972, 1973, 1974)

Kaehler and Hsieh (1994)

01/24/88

01/24/88

240

Pumping

17S/2E-6R2

0.082

Drawdown

1.3

0.26

17

0.002

ND

Kaehler and Hsieh (1994)

Kaehler and Hsieh (1994)

01/20/88

01/20/88

460

Pumping

16S/2E-31N4

0.043

Drawdown

0.34

5.2

4.6

0.00004

0.006

Neuman (1972, 1973, 1974)

Kaehler and Hsieh (1994)

01/24/88

01/24/88

240

Pumping

17S/2E-6R2

0.082

Drawdown

0.026

0.079

0.93

0.00001

ND

Kaehler and Hsieh (1994)

Kaehler and Hsieh (1994)

01/15/88

01/15/88

390

Pumping

17S/2E-6F9

0.25

Drawdown

0.0052

0.26

0.18

0.00004

ND

Kaehler and Hsieh (1994)

Kaehler and Hsieh (1994)

Same

4.08

Drawdown

11

ND

200

ND

ND

Cooper and Jacob (1946)*

Westphal et al. (1975)

MESOZOIC AND PERMIAN SEDIMENTARY ROCKS 08/27/74

08/27/74

540

Pumping

May-80

May-80

120

Drill-stem

Same

0.40

Recovery

0.00043

ND

0.0065

ND

ND

Horner (1951)

McKay and Kepper (1988)

1968

1968

180

Drill-stem

Same

0.24

Recovery

0.0070

ND

0.094

ND

ND

Geldon (1989)

Geldon (1989)

1970

1970

120

Drill-stem

Same

0.12

Recovery

0.00019

ND

0.0019

ND

ND

Horner (1951)

Geldon (1989)

1972

1972

30

Drill-stem

Same

ND

Recovery

0.034

ND

0.16

ND

ND

Horner (1951)

Geldon (1989)

1969

1969

180

Drill-stem

Same

0.44

Recovery

0.0024

ND

0.020

ND

ND

Horner (1951)

Geldon (1989)

1963

1963

ND

Drill-stem

Same

ND

Recovery

0.00076

ND

0.0070

ND

ND

Horner (1951)

Geldon (1989)

1973

1973

60

Drill-stem

Same

0.56

Recovery

0.00058

ND

0.0041

ND

ND

Horner (1951)

Geldon (1989)

1969

1969

ND

Drill-stem

Same

ND

Recovery

0.0018

ND

0.022

ND

ND

Horner (1951)

Geldon (1989)

1962

1962

60

Drill-stem

Same

0.11

Recovery

0.0014

ND

0.0060

ND

ND

Geldon (1989)

Geldon (1989)

09/15/66

09/15/66

2,880

Pumping

Same

2.8

Specific capacity

0.43

ND

17

ND

ND

Driscoll (1986)

Geldon (1989)

03/03/69

03/03/69

2,880

Pumping

Same

6.4

Specific capacity

0.13

ND

6.4

ND

ND

Driscoll (1986)

Geldon (1989)

02/20/69

02/20/69

2,880

Pumping

Same

2.5

Specific capacity

0.055

ND

2.1

ND

ND

Driscoll (1986)

Geldon (1989)

1958

1958

ND

Drill-stem

Same

ND

Recovery

0.28

ND

4.9

ND

ND

Horner (1951)

Geldon (1989)

1970

1970

120

Drill-stem

Same

0.11

Recovery

0.00012

ND

0.0012

ND

ND

Horner (1951)

Geldon (1989)

1957

1957

ND

Drill-stem

Same

ND

Recovery

0.00046

ND

0.014

ND

ND

Horner (1951)

Geldon (1989)

1970

1970

90

Drill-stem

Same

1.4

Recovery

0.0015

ND

0.052

ND

ND

Horner (1951)

Geldon (1989)

1953

1953

ND

Drill-stem

Same

ND

Recovery

0.0019

ND

0.014

ND

ND

Horner (1951)

Geldon (1989)

86

A.L. Geldon

Observation well

UTM east coordinate (m)

UTM north coordinate (m)

Altitude (m AMSL)

Well depth (m)

Top (m)

Bottom (m)

SWL (m below LSD)

Radius or interwell distance (m)

Rock Creek Federal #1

482,257.95

4,120,140.35

1,267.1

1,209.8

969.3

983.0

ND

0.049

White Rim Sandstone

Gypsiferous sandstone

Needles #4

605,886.26

4,222,171.66

1,548.4

23.5

7.3

23.5

ND

ND

Cedar Mesa Sandstone

Quartz sandstone

Carter Federal #2

565,349.55

4,252,597.26

1,681.3

1,686.8

981.2

991.5

ND

0.049

Cutler Group

Sandstone, siltstone, and shale

Carter Federal #2

565,349.55

4,252,597.26

1,681.3

1,686.8

1,077.2

1,093.3

ND

0.049

Cutler Group

Limestone, dolomite, and sandstone

Hans Flat well

571,892.17

4,234,532.03

2,002.5

838.2

777.2

838.2

ND

0.11

Cutler Group

Sandstone, shale, and limestone

Government #1

545,553.42

4,224,044.04

1,672.1

1,920.5

1,102.8

1,111.9

ND

0.049

Cutler Group

Limestone and sandstone

Poison Springs USA #A-2

535,177.22

4,220,663.82

1,490.8

1,633.1

1,208.8

1,212.8

ND

0.049

Cutler Group

Siltstone and shale

Geologic Unit

Lithologic description

(D36-18) 31cb-1

ND

ND

ND

ND

178.3

404.5

ND

ND

Cutler Group

Sandstone and shale

Elk Ridge #1

ND

ND

2,029.5

1,057.4

127.1

494.1

ND

0.050

Cutler Group

Sandstone, shale, and limestone

PALEOZOIC CARBONATE ROCKS EH-4

703,978.00

4,064,562.00

589.2

86.9

35.1

86.9

35.1

4,083

Bird Spring Formation

Karstic, fractured dolomite and limestone

MX-CE-DT-4

688,084.81

4,074,032.58

662.2

203.9

107.4

203.9

107.4

96.6

Monte Cristo Limestone

Karstic, fractured limestone and cherty limestone

MX-CE-DT-4

688,084.81

4,074,032.58

662.2

203.9

107.5

203.9

107.5

0.13

Monte Cristo Limestone

Karstic, fractured limestone and cherty limestone

MX-CE-DT-6

697,525.01

4,071,193.18

693.3

285.6

139.4

285.6

139.4

0.13

Monte Cristo Limestone

Faulted, fractured limestone

DOC Federal 5-18

601,489.88

4,238,854.06

1,467.0

1,771.8

1,728.5

1,745.0

ND

0.089

Joana Limestone

Cherty limestone

Adobe Federal 19-1

650,521.49

4,208,938.44

1,527.7

2,348.8

2,286.0

2,348.8

ND

0.089

Joana Limestone

Cherty limestone

Grant Canyon #5

623,881.20

4,256,955.56

1,442.9

1,462.4

1,386.2

1,416.7

ND

0.089

Guilmette Formation

Limestone and dolomite

Grant Canyon #4

624,551.78

4,257,490.06

1,443.8

1,286.3

1,229.6

1,237.8

ND

0.089

Guilmette Formation

Limestone and dolomite

Grant Canyon #3

624,157.79

4,257,884.77

1,443.8

1,311.2

1,199.1

1,207.3

ND

0.089

Guilmette Formation

Limestone and dolomite

Bacon Flat #1

622,749.24

4,258,048.12

1,440.5

1,661.2

1,620.0

1,629.5

ND

0.070

Guilmette Formation

Limestone and dolomite

Adobe Federal 16-1

601,489.88

4,238,938.44

1,447.5

1,202.4

1,153.7

1,197.9

ND

0.089

Guilmette Formation

Limestone and dolomite

Lone Tree 1-14-43

619,157.87

4,248,467.47

1,449.0

1,386.8

1,332.6

1,350.3

ND

0.089

Guilmette Formation

Limestone and dolomite

U-3cn 5

586,909.64

4,101,710.24

1,222.9

923.5

863.2

923.5

494.8

0.074

Guilmette Formation

Faulted, brecciated dolomite, dolomitic limestone, and quartzite

Dobbin Creek Fed A-1-6

533,461.88

4,315,961.48

2,140.0

1,426.2

1,112.5

1,229.6

ND

0.089

Guilmette Formation

Dolomite

Dobbin Creek Fed A-1-6

533,461.88

4,315,961.48

2,140.0

1,426.2

1,097.3

1,115.6

ND

0.089

Simonson Dolomite

Dolomite

Dobbin Creek Fed A-1-6

533,461.88

4,315,961.48

2,140.0

1,426.2

975.4

1,060.1

ND

0.089

Sevy and Laketown Dolomites

Dolomite

Grant Canyon #1

624,170.17

4,257,083.35

1,443.2

1,367.6

1,322.8

1,353.6

ND

0.089

Simonson Dolomite

Vuggy, brecciated dolomite

ER-12-1

572,411.44

4,115,492.80

1,773.5

1,093.6

516.0

555.0

470

0.21

Simonson Dolomite

Thrust-faulted, brecciated dolomite

NCAP-DR-1

642,194.31

4,046,912.86

1,090.9

292.6

262.1

292.6

248.6

0.12

Simonson Dolomite

Sparsely fractured dolomite

ER-6-1

589,617.88

4,093,417.75

1,200.9

977.2

554.6

649.1

476.8

0.16

Sevy Dolomite

Dolomite

UE-25 p#1

551,508.58

4,075,662.87

1,114.2

1,805.0

1,297.2

1,805.3

360.9

0.098

Simonson and Laketown Dolomites

Faulted, fractured, and vuggy dolomite

Test Well 2

581,016.62

4,113,486.03

1,362.5

882.7

823.9

882.7

626.8

0.10

Pogonip Group

Dolomite

Test Well 2

581,016.62

4,113,486.03

1,362.5

1,043.0

896.1

1,043.0

631.1

0.10

Pogonip Group

Fractured dolomite, shaly limestone, and argillite

UE-7ns

588,641.95

4,106,104.55

1,331.9

672.1

600.7

672.1

600.7

0.14

Pogonip Group

Faulted, very fractured, locally vuggy limestone

Test Well 3

601,938.92

4,074,016.96

1,063.5

564.8

363.3

564.8

336.2

0.089

Pogonip Group

Faulted, brecciated dolomite, fractured limestone, and shale

Implications for groundwater flow in the Southwest Nevada Volcanic Field

Test start

Test end

Test length (min)

Test type

Production well

Discharge or injection rate (L/s)

Analyzed Data

Kr (m/d)

Kz (m/d)

T (m2/d)

Storativity

Specific yield

1970

1970

180

Drill-stem

Same

0.30

Recovery

0.021

ND

0.28

ND

05/20/65

05/20/65

ND

Pumping

Same

0.82

Specific capacity

0.76

ND

12

1956

1956

ND

Drill-stem

Same

ND

Recovery

0.00049

ND

1956

1956

ND

Drill-stem

Same

ND

Recovery

0.00049

11/05/73

11/05/73

480

Pumping

Same

0.32

Specific capacity

1957

1957

ND

Drill-stem

Same

ND

1959

1959

ND

Drill-stem

Same

ND

87

Analyical method

Sources of hydraulicproperty data, test analyses, and supporting information

ND

Geldon (1989)

Geldon (1989)

ND

ND

Driscoll (1986)

Geldon (1989)

0.0051

ND

ND

Earlougher (1977)

Geldon (1989)

ND

0.0079

ND

ND

Earlougher (1977)

Geldon (1989)

0.0058

ND

0.35

ND

ND

Lohman (1979)

Geldon (1989)

Recovery

0.00076

ND

0.0070

ND

ND

Earlougher (1977)

Geldon (1989)

Recovery

0.00037

ND

0.0014

ND

ND

Horner (1951)

Geldon (1989)

ND

ND

ND

Pumping

Same

ND

ND

0.0082

ND

1.9

ND

ND

ND

Geldon (1989)

Mar-82

Mar-82

416

Pumping

Same

0.30

Drawdown

0.00091

ND

0.29

ND

ND

Cooper and Jacob (1946)

Geldon (1989)

Buqo (1994)

PALEOZOIC CARBONATE ROCKS 12/09/93

04/09/94

174,240

Pumping

Arrow Canyon

183.0

Drawdown

660

ND

34,000

ND

ND

Cooper and Jacob (1946)

08/28/81

09/27/81

29,021

Pumping

MX-CE-DT-5

214.5

Drawdown

520

100

50,000

ND

ND

Neuman (1975)* Berger et al. (1988)

12/20/80

12/23/80

4,620

Pumping

Same

34.0

Drawdown

190

ND

19,000

ND

ND

Cooper and Jacob (1946)

Berger et al. (1988)

12/09/86

12/12/86

3,963

Pumping

Same

29.8

Drawdown

5.1

ND

740

ND

ND

Cooper and Jacob (1946)

Berger et al. (1988)

Nov-86

Nov-86

120

Drill-stem

Same

3.88

Recovery

0.47

ND

7.8

ND

ND

Horner (1951)

McKay and Kepper (1988)

Oct-79

Oct-79

120

Drill-stem

Same

ND

Recovery

1.2

ND

76

ND

ND

Horner (1951)

McKay and Kepper (1988)

Aug-84

Aug-84

60

Drill-stem

Same

2.14

Recovery

0.14

ND

4.3

ND

ND

Horner (1951)

McKay and Kepper (1988)

Jun-84

Jun-84

62

Drill-stem

Same

5.2

Recovery

5.8

ND

46

ND

ND

Horner (1951)

McKay and Kepper (1988)

Aug-84

Aug-84

60

Drill-stem

Same

1.42

Recovery

2.6

ND

21

ND

ND

Horner (1951)

McKay and Kepper (1988)

Jul-81

Jul-81

ND

Drill-stem

Same

0.25

Recovery

0.040

ND

0.39

ND

ND

Horner (1951)

McKay and Kepper (1988)

Oct-82

Oct-82

60

Drill-stem

Same

1.59

Recovery

0.74

ND

33

ND

ND

Horner (1951)

McKay and Kepper (1988)

Feb-87

Feb-87

120

Drill-stem

Same

11.8

Recovery

0.033

ND

0.58

ND

ND

Horner (1951)

McKay and Kepper (1988)

03/06/67

04/06/67

43,288

Pumping

Same

4.99

Drawdown

0.11

ND

3.4

ND

ND

Cooper (1963)*

Garber and Johnston (1967)

Jan-85

Jan-85

3,768

Drill-stem

Same

1.0

Recovery

0.012

ND

1.1

ND

ND

Horner (1951)

McKay and Kepper (1988)

Jan-85

Jan-85

93

Drill-stem

Same

0.12

Recovery

0.0061

ND

0.049

ND

ND

Horner (1951)

McKay and Kepper (1988)

Jan-85

Jan-85

1,245

Drill-stem

Same

1.57

Recovery

0.034

ND

0.76

ND

ND

Horner (1951)

McKay and Kepper (1988)

Sep-83

Sep-83

60

Drill-stem

Same

0.85

Recovery

0.026

ND

0.79

ND

ND

Horner (1951)

McKay and Kepper (1988)

01/04/93

01/05/93

1,683

Pumping

Same

3.15

Drawdown

1.7

ND

38

ND

ND

Hydrogeochem, Inc. (1988)

Russell et al. (1996)

02/03/89

02/04/89

1,638

Pumping

Same

0.91

Drawdown

1.4

ND

42

ND

ND

Cooper and Jacob (1946)

Dettinger et al. (1995)

Nov-92 (?)

Nov-92 (?)

ND

Pumping

Same

ND

Drawdown

14

ND

1,300

ND

ND

Theis (1935)

IT Corporation (1996)

05/08/83

05/12/83

6,080

Pumping

Same

31.5

Drawdown

0.46

ND

110

ND

ND

Cooper and Jacob (1946)

Craig and Robison (1984); Carr et al. (1986)

01/15/62

01/15/62

177

Swabbingrecovery

Same

0.79

Residual drawdown

0.044

ND

2.6

ND

ND

Theis (1935) recovery*

Moore et al. (1963)

03/16/62

03/20/62

5,130

Pumping

Same

3.78

Drawdown

0.065

ND

4.9

ND

ND

Cooper and Jacob (1946)

Moore et al. (1963)

04/02/84

04/25/84

33,415

Pumping

Same

0.091

Drawdown

0.012

ND

0.89

ND

ND

Theis (1935)

Winograd and Rush (unpublished report)

05/09/62

05/10/62

1,000

Pumping

Same

1.89

Drawdown

0.032

ND

2.2

ND

ND

Neuman (1975)* Meyer and Young (1962); Winograd (1965)

88

A.L. Geldon

Observation well

UTM east coordinate (m)

UTM north coordinate (m)

Altitude (m AMSL)

Well depth (m)

Top (m)

Bottom (m)

SWL (m below LSD)

Radius or interwell distance (m)

Test Well E

589,358.97

4,101,335.13

1,271.6

798.6

765.0

798.6

561.7

0.078

Geologic Unit

Lithologic description

Pogonip Group

Cherty dolomite

UE-2ce WW

576,799.00

4,110,765.30

1,452.2

502.9

434.6

502.9

434.6

0.16

Pogonip Group and Nopah Fm

Fractured dolomite

Test Well 4

607,599.05

4,049,554.31

1,060.4

454.2

224.2

454.2

224.2

0.10

Nopah Formation

Faulted, fractured dolomite and limestone

UE-1q

583,722.70

4,101,770.53

1,244.1

792.5

749.5

792.5

504.6

0.091

Nopah Formation

Fractured, shaly limestone and dolomite

Test Well 10

602,673.84

4,049,894.72

1,087.8

396.5

297.2

396.5

255.2

0.21

Bonanza King Formation

Faulted, very fractured cherty limestone, dolomitic limestone, and dolomite

UE-10j

581,538.31

4,115,648.40

1,394.1

796.4

670.1

795.7

658.7

0.16

Bonanza King Formation

Fractured dolomite and limestone

Army #1 WW

586,119.84

4,049,799.54

961.3

593.1

239.8

593.1

239.8

0.13

Bonanza King Formation

Faulted, fractured dolomite and limestone

ATS TH-1

569,251.85

4,043,609.54

733.1

253.0

188.5

253.0

13.7

122.8

Bonanza King and Carrara Fms

Thrust-faulted, brecciated, vuggy dolomite and limestone

ATS TH-3

569,185.54

4,043,594.14

732.0

246.0

185.9

246.0

12.6

69.2

Bonanza King and Carrara Fms

Thrust-faulted, brecciated, vuggy dolomite and limestone

ATS SH-1

569,208.93

4,043,614.03

733.0

202.4

185.9

202.4

13.5

97.5

Bonanza King and Carrara Fms

Thrust-faulted, brecciated, vuggy dolomite and limestone

Variable

Variable

Variable

Variable

Variable

Variable

12.6-13.7

69.2122.8

Bonanza King and Carrara Fms

Thrust-faulted, brecciated, vuggy dolomite and limestone

ATS TH-1, TH-3, SH-1

PALEOZOIC AND PROTEROZOIC CLASTIC ROCKS White River Valley #6

664,823.01

4,261,208.53

1,595.9

1,921.8

1,368.6 1,395.4

ND

0.089

Ely Limestone

Cherty limestone

White River Valley #6

664,823.01

4,261,208.53

1,595.9

1,921.8

1,639.2

1,656.6

ND

0.089

Ely Limestone

Cherty limestone

Bacon Flat #5

623,352.30

4,258,242.34

1,440.5

2,225.0

1,705.4

1,766.3

ND

0.089

Ely Limestone

Cherty limestone

Bacon Flat #5

623,352.30

4,258,242.34

1,440.5

2,225.0

1,898.3

1,912.9

ND

0.089

Chainman Shale

Calcareous shale and sandstone

Sunnyside #1

670,376.40

4,247,352.16

1,621.8

1,996.4

1,121.7

1,153.7

ND

0.089

Chainman Shale

Calcareous shale and sandstone

MX-SV-DT-2

686,967.28

4,310,179.93

2,243.3

745.8

152.4

289.6

126.3

0.076

Ely Limestone and Chainman Shale

Limestone, shale, siltstone, and sandstone

NCAP-CSV-2

703,268.86

4,072,746.49

666.3

145.7

119.1

145.7

119.1

0.11

Bird Spring Formation

Shaly limestone

MX-CE-VF-2

684,598.38

4,082,713.11

751.9

372.2

259.1

372.2

186.1

0.13

Bird Spring Formation

Dolomitic limestone and calcareous shale

UE-16d

574,003.47

4,102,761.09

1,427.7

914.4

230.5

637.0

230.5

0.11

Bird Spring Formation

Limestone, sandstone, and siltstone

UE-16d

574,003.47

4,102,761.09

1,427.7

914.4

453.0

637.0

230.5

0.11

Chainman Shale

Quartzite and argillite

UE-16f

575,003.83

4,098,976.70

1,417.8

431.0

394.1

431.0

192.1

0.11

Chainman Shale

Argillite, quartzite, quartzitic sandstone, and siltstone

UE-17a

574,127.11

4,103,160.17

1,431.5

370.0

227.1

370.0

162.9

0.079

Chainman Shale

Calcareous quartzite and argillite with limestone and sandstone

UE-1L

576,572.42

4,100,377.55

1,357.7

1,627.3

218.2

388.6

ND

0.16

Chainman Shale

Argillite with quartzite and siltstone

UE-1M

577,749.56

4,096,852.56

1,364.9

156.7

86.0

114.0

86.0

0.051

Eleana Fm and Chainman Shale

Thrust-faulted, siliceous argillite

ER-12-1

572,411.44

4,115,492.80

1,773.1

1,093.6

764.7

790.6

407.2

0.16

Eleana Formation

Argillite with siltstone and cherty sandstone

Soda Springs #1

626,384.83

4,267,442.86

1,443.5

2,454.2

2,346.7

2,376.2

ND

0.089

Sidehill Spring Formation

Quartzite

BGMW #13

519,382.47

4,059,841.33

1,002.8

339.9

272.8

341.4

250.2

0.10

Stirling Quartzite

Fractured quartzite

Test Well D

582,225.55

4,103,327.57

1,265.5

594.4

540.1

573.6

527.9

0.15

Dunderberg Shale Member of Nopah Formation

Dolomite, limestone, argillite, and siltstone

UE-15d

585,061.42

4,118,300.77

1,397.8

1,829.1

543.8

1,829.1

203.9

0.080

Stirling Quartzite to Noonday Dolomite Fractured quartzite, argillite, siltstone, and dolomite

Notes: Kr—horizontal hydraulic conductivity; Kz—vertical hydraulic conductivity; T—transmissivity; NW—nonwelded; PW—partially welded; MW—moderately welded; DW—densely welded; AMSL—above mean sea level; SWL—static water level; LSD—land surface datum; NA—not applicable; ND—no data *new or revised analysis

Implications for groundwater flow in the Southwest Nevada Volcanic Field

Test start

Test end

Test length (min)

Test type

Production well

Discharge or injection rate (L/s)

Analyzed Data

Kr (m/d)

Kz (m/d)

T (m2/d)

Storativity

Specific yield

04/20/62

04/20/62

160

Slugwithdrawal

Same

NA

Residual drawdown

0.032

ND

1.1

ND

05/25/77

05/26/77

1,440

Pumping

Same

1.64

Drawdown

0.090

ND

6.2

09/11/62

09/13/62

2,160

Pumping

Same

9.72

Drawdown

0.32

ND

30

89

Analyical method

Sources of hydraulicproperty data, test analyses, and supporting information

ND

Cooper et al. (1967)*

West and Thordarson (1965)

ND

ND

Neuman (1975)* IT Corporation (1996)

ND

ND

Neuman (1975)* Smith and Doyle (1962); Winograd (1965)

ND

ND

ND

Pumping

Same

ND

Drawdown

16

ND

670

ND

ND

Theis (1935)

IT Corporation (1996)

02/24/63

02/26/63

3,060

Pumping

Same

25.2

Drawdown

0.84

ND

21

ND

ND

Cooper (1963)*

Winograd (1965)

Mar-93 (?)

Mar-93 (?)

ND

Pumping

Same

ND

Drawdown

26

ND

2,300

ND

ND

Theis (1935)

IT Corporation (1996)

09/11/62

09/13/62

2,880

Pumping

Same

28.6

Drawdown

0.13

ND

30

ND

ND

Neuman (1975)*

Meyer and Smith (1964); Winograd (1965)

10/06/67

10/07/67

1,140

Pumping

ATS TH-2

59.9

Drawdown

270

ND

4,800

0.002

ND

Streltsova-Adams Johnston (1968); USGS (1978)* files

11/16/67

11/18/67

3,050

Pumping

ATS TH-2

59.9

Drawdown

220

ND

5,700

0.003

ND

Streltsova-Adams Johnston (1968); USGS (1978)* files

11/16/67

11/18/67

3,050

Pumping

ATS TH-2

59.9

Drawdown

180

ND

4,600

0.002

ND

Streltsova-Adams Johnston (1968); USGS (1978)* files

01/18/75

01/21/75

4,423

Pumping

ATS TH-2

58.3

Drawdown

290

ND

6,900

0.002

ND

Streltsova-Adams Johnston (1968); USGS (1978)* files

PALEOZOIC AND PROTEROZOIC CLASTIC ROCKS 1981

1981

120

Drill-stem

Same

0.28

Recovery

0.0027

ND

0.072

ND

ND

Horner (1951)

McKay and Kepper (1988)

1981

1981

120

Drill-stem

Same

0.19

Recovery

0.00049

ND

0.0086

ND

ND

Horner (1951)

McKay and Kepper (1988)

Oct-81

Oct-81

120

Drill-stem

Same

0.28

Recovery

0.000094

ND

0.0058

ND

ND

Horner (1951)

McKay and Kepper (1988)

Oct-81

Oct-81

180

Drill-stem

Same

ND

Recovery

0.00026

ND

0.0038

ND

ND

Horner (1951)

McKay and Kepper (1988)

Aug-86

Aug-86

120

Drill-stem

Same

1.3

Recovery

0.0059

ND

0.19

ND

ND

Earlougher (1977)*

McKay and Kepper (1988)

01/18/81

01/21/81

ND

Pumping

Same

6.31

Drawdown

0.088

ND

12

ND

ND

Cooper and Jacob (1946)

Dettinger et al. (1995)

06/07/86

06/08/86

1,290

Pumping

Same

6.34

Drawdown

5.4

ND

140

ND

ND

Cooper and Jacob (1946)

Dettinger et al. (1995)

02/06/86

02/06/86

830

Pumping

Same

4.85

Drawdown

5.8

ND

270

ND

ND

Cooper and Jacob (1946)

IT Corporation (1996)

06/13/77

06/14/77

1,440

Pumping

Same

35.9

Drawdown

0.76

ND

110

ND

ND

Neuman (1975)* Dinwiddie and Weir (1979)

06/13/77

06/14/77

1,440

Pumping

Same

35.9

Drawdown

0.11

ND

8.4

ND

ND

Neuman (1975)* Dinwiddie and Weir (1979)

09/24/77

09/24/77

290

Slug-injection

Same

NA

Recovery

0.0023

ND

0.086

ND

ND

Cooper et al. (1967)

Dinwiddie and Weir (1979)

09/23/76

09/23/76

240

Pumping

Same

1.26

Residual drawdown

0.0045

ND

0.11

ND

ND

Theis (1935) recovery

Weir and Hodson (1979)

04/30/72

05/01/72

570

Slug-injection

Same

NA

Recovery

0.0023

ND

0.38

ND

ND

Cooper et al. (1967)*

Sweeney (1986); USGS files

03/23/76

03/24/76

1,148

Injection

Same

0.86

Residual head rise

0.046

ND

1.3

ND

ND

Theis (1935) recovery*

Cole et al. (1997); USGS files

09/28/92

09/28/92

212

Slugwithdrawal

Same

NA

Residual drawdown

0.025

ND

0.65

ND

ND

Cooper et al. (1967)

Russell et al. (1996) McKay and Kepper (1988)

Sep-84

Sep-84

120

Drill-stem

Same

0.41

Recovery

0.0023

ND

0.067

ND

ND

Horner (1951)

07/17/99

07/19/99

3,165

Pumping

Same

7.0

Drawdown

0.14

ND

10

ND

ND

Neuman (1975)* Questa Engineering Corp. (2000b)

01/07/61

01/07/61

209

Bailingrecovery

Same

1.39

Residual drawdown

0.056

ND

0.65

ND

ND

Theis (1935) recovery*

Thordarson et al. (1962)

03/26/62

03/27/62

2,160

Pumping

Same

4.9

Drawdown

0.012

ND

8.0

ND

ND

Cooper and Jacob (1946)*

Norvitch (1962); Williams et al. (1963)

90

A.L. Geldon

REFERENCES CITED Anderson, L.A., 1981, Rock property analysis of core samples from the Yucca Mountain UE-25a-1 borehole, Nevada Test Site, Nevada: U.S. Geological Survey Open-File Report 81-1338, 36 p. Anderson, L.A., 1991, Results of rock property measurements made on core samples from Yucca Mountain boreholes, Nevada Test Site, Nevada, Part 1, Boreholes UE-25 a-4, a-5, a-6, and a-7, Part 2, Borehole UE-25 p#1: U.S. Geological Survey Open-File Report 90-474, 43 p. Anderson, L.A., 1994, Water permeability and related rock properties measured on core samples from the Yucca Mountain USW GU-3/G-3 and USW G-4 boreholes, Nevada Test Site, Nevada: U.S. Geological Survey Open-File Report 92-201, 36 p. Barker, J.A., and Black, J.H., 1983, Slug tests in fissured aquifers: American Geophysical Union, Water Resources Research, v. 19, no. 6, p. 1558–1564. Bartley, J.M., and Gleason, G., 1990, Tertiary normal faults superimposed on Mesozoic Thrusts, Quinn Canyon and Grant Ranges, Nye County, Nevada, in Wernicke, B.P., ed., Basin and Range extensional tectonics near the latitude of Las Vegas Nevada: Boulder, Colorado, Geological Society of America Memoir 176, p. 195–212. Belcher, W.R., Elliott, P.E., and Geldon, A.L., 2001, Hydraulic-property estimates for use with a transient ground-water flow model of the Death Valley regional ground- water flow system, Nevada and California: U.S. Geological Survey Water-Resources Investigations Report 01-4120, 28 p. Bentley, C.B., 1984, Geohydrologic data for test well USW G-4, Yucca Mountain area, Nye County, Nevada: U.S. Geological Survey Open-File Report 84-063, 48 p. Bentley, C.B., Robison, J.H., and Spengler, R.W., 1983, Geohydrologic data for test well USW H-5, Yucca Mountain area, Nye County, Nevada: U.S. Geological Survey Open-File Report 83-853, 34 p. Berger, D.L., Kilroy, K.C., and Schaefer, D.H., 1988, Geophysical logs and hydrologic data for eight wells in the Coyote Spring Valley area, Clark and Lincoln Counties, Nevada: U.S. Geological Survey Open-File Report 87-679, 59 p. Blakely, R.J., Jachens, R.C., Calza, J.P., and Langenheim, V.E., 1999, Cenozoic basins of the Death Valley extended terrane as reflected in regional-scale gravity anomalies in Wright, L.A., and Troxel, B.W., eds., Cenozoic basins of the Death Valley region: Boulder, Colorado, Geological Society of America Special Paper 333, p. 1–16. Blankennagel, R.K., 1967, Hydraulic testing techniques of deep drill holes at Pahute Mesa, Nevada Test Site: U.S. Geological Survey Open-File Report: Interagency Special Studies Report v. I-1, 50 p. Blankennagel, R.K., and Weir, J.E., 1965, Water production and pumping test data for exploratory holes, Pahute Mesa, Nevada Test Site: U.S. Geological Survey Technical Letter Special Studies I-40, 27 p. Blankennagel, R.K., and Weir, J.E., 1966, Summary of ground-water data pertinent to water-supply development, Pahute Mesa, Nevada Test Site: U.S. Geological Survey Technical Letter Special Studies I-27, Supplement 2, 25 p. Blankennagel, R.K., and Weir, J.E., 1973, Geohydrology of the Eastern part of Pahute Mesa, Nevada Test Site, Nye County, Nevada: U.S. Geological Survey Professional Paper 712-B, 35 p. Blankennagel, R.K., Young, R.A., Cooper, J.B., and Whitcomb, H.A., 1964, Summary of ground water data pertinent to underground construction and to water-supply development, Pahute Mesa, Nevada Test Site: U.S. Geological Survey Technical Letter Special Studies I-27, 39 p. Boulton, N.S., 1963, Analysis of data from nonequilibrium pumping tests allowing for delayed yield from storage: London, England: Institute of Civil Engineers Proceedings, v. 26, p. 469–482. Bredehoeft, J.D., and Papadopulos, S.S., 1980, A method for determining the hydraulic properties of tight formations: American Geophysical Union, Water Resources Research, v. 16, no. 1, p. 233–238. Bryant, E.A., 1992, The Cambric migration experiment: a summary report: Los Alamos, New Mexico, Los Alamos National Laboratory Report LA12335-MS, 37 p. Bunch, R.L., and Harrill, J.R., 1984, Compilation of selected hydrologic data from the MX missile-siting investigation, east-central Nevada and western Utah: U.S. Geological Survey Open-File Report 84-702, 123 p. Buqo, T.S., 1994, Results of long-term testing of the Arrow Canyon well: Blue Diamond, Nevada, Thomas S. Buqo, Consulting Hydrogeologist, Report to Moapa Valley Water District, 22 p.

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H ( µ, β ) =

∫

∞

µ

 β µ  e−y  dy: erfc  y  y( y − µ )   

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CONTENTS Introduction Location of Study Area Regional Geology Regional Groundwater Hydrology Hydrostratigraphic Units Groundwater in the Younger Tertiary Tuff and Lava Flows Hydrostratigraphic Unit Hydraulic Tests Well Completion and Instrumentation Flow Distribution in Boreholes Earth Tides and Barometric Effects Analytical Methods Constant-Rate Pumping, Injection, and Airlift Tests Slug-Injection and Swabbing Recovery Tests Analytical Uncertainty Effects atTest Scale on Determination of Hydraul ic Properties Hydraulic Properties The C-holes Complex Pumping Test in UE-25 c#3, May 22 to June 1, 1995 Miscellaneous Hydraulic Tests at the C-holes Complex, 1984-1998 Pumping Test in UE-25 c#3, May 8, 1996, to Novembe r 12, 1997 Drill Hole Wash Frenchman Flat Well Cluster ER-20-6, Weste rn Pahute Mesa Knickerbocker Site, Western Pahute Mesa Distribution of Hydraulic Conductivity Relation of Lithology to Hydrau lic Conductivity Hydraulic Conductivity Distribution at Yucca Mounta in Hydraulic Conductivity Distribution at Pahute Mesa Summary and Conclusions Appendix A Appendix B References Cited

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