University of Nevada

Reno

Delineation of Subsurface Flow in the Upper Meadow Valley Wash Area \ Southeastern Nevada

A thesis submitted in partial fulfillment of the

requirements for the degree of Master of Science in

Hydrology and Hydrogeology

by

David H. Emme <''

December 1986

UNIVERSITY Of NEVADA LIBRARY i MINES LIBRARY Ttizsi's A I 5 The thesis of David. H. Emme is approved: f

University of Nevada

Reno

December 1986 ii

ACKNOWLEDGEMENTS

I would like to thank Mike Dettinger and Jim Thomas of the U-S-_ Geological Survey for suggesting this project and providing critical comments through its course. Committee members Mike Campana, Roger Jacobson and Ed Wagner deserve thanks for serving on my graduate committee. Particular gratitude is extended to Mike ^ Campana for serving as committee chairman and providing continuous support and encouragement through a frustrating experience. Excellent critical review by Roger Jacobson is also appreciated, although receiving this review prior to my thesis defense would have been appreciated even more. Finally, thanks go out to friends who remained friends and to my parents for providing support for too many years. ABSTRACT

The study area is located within the Great Basin carbonate

rock province, which contains regionally extensive aquifer systems.

Panaca Spring discharges approximately 8000 acre-feet/year from

carbonate rocks in the study area. Results of simple mixing

calculations, using chloride concentration and S D to weight

recharge estimates, suggest that sources of regional flow lie to

the north in Lake Valley and Patterson Wash. Three scenarios were

proposed to describe groundwater flow conditions in Lake Valley and

Patterson Wash: 1) a well mixed, single layer system; 2) a two

layer, local and regional system with upward vertical leakage; and

3) a two layer system with downward vertical leakage. The latter scenario yields a match of predicted flow rate, 5 D and chloride concentration with that observed at Panaca Spring, and appears to adequately describe local groundwater flow conditions in Patterson

Wash. This two layer scenario requires that regional recharge be derived from carbonate mountain blocks and local recharge from volcanic terrain. Since most of the estimated regional flow is accounted for by discharge at Panaca Spring substantial interbasin transfer does not appear likely. TABLE of CONTENTS

Tag1 ACKNOWLEDGEMENTS..

ABSTRACT......

LIST of FIGURES....

LIST of TABLES......

INTRODUCTION Objectives and Scope. Setting...... Previous Work... Methods and Procedures

GEOLOGY General Statement.... Hydrostratigraphic Units.... Structure......

HYDROLOGY General Statement...... Surface Water.... Groundwater......

AQUEOUS GEOCHEMISTRY General Statement...... Major Constituent Geochemistry.. Chloride Balance...... Deuterium Balance....

DISCUSSION......

CONCLUSIONS......

RECOMMENDATIONS......

REFERENCES......

APPENDIX 1. Summary of well data, U.S. Geological Survey unpublished data...... 78

APPENDIX 2. Location and physical characteristics of samples collected in the Meadow Valley Wash Area...... 81 V

APPENDIX 3. Analyses of major constituents in mg/1, Meadow Valley Wash Area......

APPENDIX 4. Log IAP/KT with respect to calcite and dolomite,calculated by WATEQF(Plummer et al., 1976)

APPENDIX 5. Stable isotope data for the Meadow Valley Wash Area...... 89 LIST of FIGURES

Page

1. Location of the study area within the carbonate rock province of Nevada, after Winograd and Friedman (1972). 2

2. Location map of the study area. ^

3. General geologic map of the study area, after Tschanz and Pampeyan (1970). 12

4. General map of major structures, compiled from Ekren et al (1970)’ R°Wley 8t a1, <1978) and Tschanz and Pampeyan

5. Comparison of water levels in two observation wells (USGS unpublished data) and estimated annual pumpage in Panaca Valley (Nevada State Engineer's office, unpublished data) . ’ j_g

6. Water levels, in feet above sea level, within the study area (U.S. Geological Survey, unpublished data). 22

7. Location of ground water and surface water sample sites. 25

8 ‘ Trilinear plot of ground water samples from the study area.26

9. Chloride versus calcium for groundwater samples in the study area, compared to an arbitrary 1:1 line. 28

10. Chloride versus bicarbonate for groundwater samples in the study area, compared to an arbitrary 1:1 line. 29

11. Chloride versus magnesium for groundwater samples in the study area, compared to an arbitrary 1:1 line. 30

12. Chloride versus sulfate for groundwater samples in the study area, compared to an arbitrary 1:1 line. 32

13. Chloride versus sodium for groundwater samples in the study area, compared to an arbitrary 1:1 line. 33

14. Del Oxygen-18 versus del Deuterium for groundwater and surface water samples in the study area. 36

15. Chloride versus del Deuterium for groundwater samples in Lake Valley. 3g vii

Page

16. Chloride versus del Deuterium for Panaca Valley sites and Caliente thermal water.

17. Spatial distribution of chloride concentration, in mg/1, within the study area.

18. Division of sub-drainages and associated chloride concentrations in Patterson Wash.

19. Spatial distribution of deuterium, permil, in the study area. 55 viii

LIST of TABLES

Page

1. Surface water data for upper Meadow Valley Wash. Data is derived from continuous record except as noted. 18

2. Summary of spring flow measurements, compiled bv Garside and Schilling (1979). ' 21

3. Reconnaissance water budget for the Meadow Valley Wash area, after Rush (1964) and Rush and Eakin (1963). 46

4. Summary of chloride balance calculations for Patterson Wash. 48

5. Summary of chloride balance calculations for Patterson Wash, assuming a two layer system with a vertical gradient. 50

6. Deuterium balance calculations for inflows to regional and local flow systems within the study area. 63 INTRODUCTION

Objectives and Scope

The upper Meadow Valley Wash area lies within the

miogeosynclinal carbonate rock province of eastern and southern

Nevada (Figure 1). The enormous thickness of these Paleozoic rocks

coupled with development of secondary porosity, in the form of

fractures and solution openings, favors regional groundwater flow.

Large discharge springs issuing from carbonate outcrops demonstrate

the occurrence and movement of water within these rocks.

Development of water resources contained in the carbonate rocks

has been proposed by a variety of interests. Prior to development,

flow system boundaries need to be delineated and interaction with

overlying aquifer systems described. The relative paucity of data

representing flow in the carbonate system makes the task

difficult. Recharge mechanisms are poorly understood and discharge

observations are confined to widely scattered springs and few wells.

Within the upper Meadow Valley Wash area, a definite bias exists in available data toward basin fill systems rather than a carbonate system. In fact all wells in the study area are completed in basin fill and there may only be one major spring that can be cogently defined as a carbonate discharge area. Given OREGON DAHO

Figure 1. Location of the study area within the carbonate rock province of Nevada, after Winograd and Friedman (1972). available sampling points strict delineation of the carbonate flow

system is impossible. Instead, objectives of the study are to

develop a refined conceptual model that describes potential sources

of deep circulating groundwater and the degree of interaction

between this flow and shallower basin fill aquifers.

Interpretations are based on a synthesis of historical geochemical,

geologic and hydraulic data, supplemented by stable isotope and

geochemical data collected specifically for this study.

Setting

Upper Meadow Valley Wash, as defined for this project,

encompasses approximately 2000 square miles of southeastern Nevada.

The area is composed of several small basins connected by a common

drainage system that forms Meadow Valley Wash. Sub-basins include:

Patterson Wash, Spring Valley, Dry Valley, Panaca Valley and Clover

Valley (Figure 2). Lake Valley, though topographically closed, is

also included in the study area since water level data indicates a

gradient to the south (Rush, 1964).

Topographically, the area is characterized by valley floors ranging from altitudes of 4000 feet near Caliente to 6000 feet in

Spring and Lake Valleys. Mountainous divides defining the perimeter of the area range from approximately 6000 feet in the

Clover Mountains to nearly 11000 feet in the Schell Creek Range of

Lake Valley. Recognize that the topographic divide defining the study area may not reflect a groundwater divide but serves to . Location map of the study area Figure Figure 2

Scholl Creek Range delimit the scope of the project. Hydrologic boundaries will be

evaluated in a subsequent section.

There are three small communities in the area, each having

populations of fewer than 1000 residents: Pioche, Panaca and

Caliente. Pioche has historically been the center for a

substantial mining district, though agriculture is the chief

industry of the area.

Climate ranges from semi-arid in the valleys to sub-humid in

the mountains. Precipitation is dependent on altitude with measured average annual values ranging from 9 inches at Caliente to

16 inches in the mountains east of Caliente (Rush, 1964).

Precipitation can result from Pacific storms or Great Basin low pressure systems. Since Pacific storms are generally moisture deficient upon reaching eastern Nevada, Great Basin lows are the chief source of precipitation in the area (Houghton et al, 1975).

Heavy snowfall can result from Great Basin lows in the colder

• Precipitation is also derived from localized thunderstorms during the summer months. Flash flooding often results from these events.

Previous Work

Previous hydrologic investigations have been confined to reconnaissance level descriptions. Carpenter (1915) orovides brief descriptions of geology, topography and springs in southeastern

Nevada. In a comprehensive delineation of flow systems in Nevada, Mifflin (1968) describes the upper Meadow Valley Wash area as a

mixed system containing local and regional components. Mifflin

used large discharge springs in the White River Valley as type

springs to distinguish regional versus local chemical character.

Regional springs were defined as those containing less than 8 T.U.

(tritium units) of tritium and having concentrations of Na + K and

Cl + S04 greater than 1 epm (equivalent per million). Groundwater

resources of the Panaca and Caliente area are described by Phoenix

(1948). The most complete hydrologic appraisal of the area is

found m state reconnaissance series reports for Lake Valley (Rush

and Eakin, 1963) and Meadow Valley Wash (Rush, 1964). Much of the

information contained in these reports will be used as a foundation

for this work, including simplified water budget calculations.

Chemical data has been collected by Bateman (1976) in an

inventory of sources of salinity to the Colorado River system.

Additional chemical data is available from an assessment of the geothermal resources of the Caliente area by Trexler (1980).

Methods and Procedures

A total of 38 sites were sampled on two separate occasions in

April and June of 1985. High altitude springs (above 6000 feet) were sampled from the mountain ranges of the study area and presumed to be indicative of recharge chemistry. Springs and wells were sampled from the valley floor, with the aim being to achieve a geographic distribution of sample sites and obtain samples

representing carbonate and alluvial aquifers if possible.

Samples for analyses of major cations, anions, trace elements,

and stable isotopes of oxygen and hydrogen were collected. Spring

samples were collected from the spring orifice where possible.

Some springs have been developed and collection was from a

discharge pipe down gradient. Well samples were collected from

pumping wells exclusively, and as close to the well as possible.

Most wells sampled are used for irrigation thus pumping rates are

generally high and samples considered representative of aquifer

chemistry. Two windmills were also sampled, though generally

samples from windmills may be questionable due to low flow rates.

However, both wells were sampled in the afternoon and had

presumably been pumping most of the day judging from wind

conditions.

Field measurements included water temperature, specific

conductance, pH, and alkalinity. Specific conductance was measured with a Fisher conductivity meter equipped with an internal

temperature correction device, thus values are normalized to 25 deg

C (degrees Celsius). The meter was calibrated prior to sample measurement using conductivity standards bracketing the conductance of the sample. Sample pH was determined with a Markson pH meter equipped with a Ross combination pH electrode. Prior to measurement pH buffer solutions were allowed to equilibrate to sample water temperature and used to calibrate the meter. Alkalinity was determined by incremental titration using a Hach

digital titrator and cartridges of 0.16 N sulfuric acid.

Alkalinity is reported in terms of mg/1 (milligrams per liter) of

bicarbonate. Since all samples had a pH less than 8.3 no carbonate

was detected by field titration.

Anion samples were filtered and collected in plain 250 ml

plastic bottles. Cation and trace element samples were filtered,

collected in acid rinsed 250 ml plastic bottles and preserved with

2 ml of nitric acid. Stable isotope samples were collected in 25

ml glass bottles sealed with polyseal caps. The caps were sealed

with electrical tape in the field and sealed with wax upon return

to the office. All samples were mailed to the U.S. Geological

Survey Denver Central Laboratory for analysis.

Stable isotope data is expressed in parts per thousand or permil, representing a comparison of the ratio of heavy to light isotopes in the sample to that in some standard. The standard for oxygen and hydrogen isotopes is standard mean ocean water or SMOW.

The S notation for oxygen and hydrogen isotopes is as follows:

5 D =■ (D/H) sample - (D/H)std

------— x 1000

(D/H)std

1 8 5 0 = (0-18/0-16)sample - (0-18/0-16)std

x 1000

(0-18/0-16)std where D and 0-18 are deuterium and oxygen-18 and std is the

standard. The abbreviations 6 D and S **0 will be used in

subsequent discussion and units will be understood to be permil.

Additional chemical and isotopic data has been compiled from

two previous investigations. In an effort to fill geographic gaps

m the data set of this study several analyses of sites sampled by

Bateman (1976) have been incorporated into the data base.

Similarly, isotopic and chemical data collected by Trexler (1980)

have also been included in the data set for this study. Stable

isotope samples from the Trexler study were analyzed by the

University of Arizona Laboratory of Isotope Geochemistry. Of

concern in use of this data are possible interlaboratory

c^fferences i-n isotopic values derived from similar samples. The

only duplicate samples that allow interlaboratory comparison were collected from the Hot Springs Motel in Caliente. Trexler cites 5 D 1 8 and S 0 values of -106 and -14.3 permil respectively, compared to the sample collected for this study with values of -109 and -14.5 1 8 permil. Since the analytical error for 5 D and 5 0 is 1.5 and

0.15 respectively, the two samples are marginally within the range of analytical error.

GEOLOGY

General Statement

Given the regional extent of the study area geologic description will be limited to a general overview, focusing on 10

geologic conditions that may exert control on groundwater flow. Of

particular interest are delineation of potential aquifers and

aquitards based on stratigraphic relationships and determination of

possible structural control of groundwater flow.

Previous geologic investigations have been conducted at a

regional reconnaissance level and at a local scale associated with

mineral deposits. Reconnaissance descriptions of the geology and

mineral deposits of Lincoln County are provided by Tschanz and

Pampeyan (1970). Phoenix (1948) has described the geology and

groundwater resources of Meadow Valley Wash extending from

Patterson Wash in the north to Caliente in the south. Caldera

complexes and associated volcanic rocks have been mapped by Noble

(1968) and Noble and McKee (1972). More detailed geologic mapping

has been confined to mineral districts, most notably the Pioche

mineral district. Westgate and Knopf (1932) present a detailed

account of the geology and ore deposits of the Pioche district.

Later mapping was performed by Park et al.(1958). Cambrian rocks

constitute host rocks for most ore deposits in the district.

Stratigraphy of these rocks has been described by Wheeler (1940)

and Merriam (1964).

Hydrostratigraphic Units

Pertinent to this study are the water transmitting capabilities

of different lithologic units, thus a generalized description of hydrostratigraphic units will be provided in lieu of a detailed account of stratigraphy. Hydrostratigraphic units are grouped in 11

accordance with division established by Rush (1964) which include

Paleozoic carbonates, non-carbonate rocks, and unconsolidated

valley fill deposits.

Paleozoic carbonate rocks have been shown to be capable of

transmitting large volumes of water. Fractures and solution

channels dissecting carbonate rocks can provide substantial

secondary porosity. Evidence of this porosity can be observed in

Condor Canyon, northeast of Panaca. Outcrop of carbonate rocks in

this narrow canyon are characterized by numerous fractures and

solution cavities. In addition, Panaca Spring, near the mouth of

the canyon, discharges a relatively large rate of flow from

carbonate rocks.

Notable outcrops of Paleozoic carbonate rocks occur in the

Schell Creek, Fortification, and Ely Ranges of southern Lake

Valley, and the Bristol and Highland Ranges west of Patterson Wash

(Figure 3). Generally the Paleozoic section thins from northwest to

southeast, apparently associated with transition from

miogeosyncline to craton (Tschanz and Pampeyan, 1970).

Non-carbonate rocks include Paleozoic clastic rocks, primarily

quartzite and shale, and Tertiary volcanics. Primary porosity of

these rocks is very low, though secondary porosity can provide

conduits for flow. Winograd and Thordarson (1975) interpret

Paleozoic elastics as aquitards and describe permeability of

volcanics as dependent on density of fractures and in tuffs, degree

of welding. Numerous springs discharge from the Tertiary volcanics within the study area, although flow rates are low and intermittent 12

Scholl Creek Range 13

m nature. Paleozoic elastics are found interbedded with the

carbonates with prominent outcrops in northern Lake Valley.

Tertiary volcanic rocks occur in the mountains adjacent to Spring

Valley and near a caldera complex centered in Clover Valley.

Unconsolidated valley fill deposits are composed of Pleistocene

lake bed and older alluvial deposits, and recent alluvium. Lake bed deposits are referred to as the Panaca Formation, which has been correlated to the Muddy Creek Formation mapped farther south m Clark County. Lake Valley, Spring Valley and Panaca Valley contain these Pleistocene lake bed deposits though most recent deposits are found in Lake Valley.

Structure

Generally, the structural features of the study area can be distinguished as Laramide and post-Laramide age. Dominant Laramide structures include thrust faults and northeast trending strike-slip faults. Post-Laramide structures predominantly consist of basin and range type normal faults. Laramide structures suggest much greater movement than later structural features.

A significant amount of work has been done concerning east- west lineaments in east-central Nevada and western Utah. Tschanz and Pampeyan (1970) describe a series of parallel northeast trending strike-slip faults in the Pahranagat Range, west of the study area. The southernmost fault, the Maynard Lake fault, is inferred to extend northeast through the Caliente area (Figure 4). Figure 4. General map of lineaments, compiled from Ekren et ai, 1976, Rowley et al, 1978 and Tschanz and Pampeyan, 1970. Ekren et al. (1976) mapped the Timpahute lineament, using

LANDSAT data, extending through the Galiente area (Figure 4). The

lineament appears to control the location of intrusive bodies and

volcanic centers, is the locus of recent seismicity and interrupts

north-trending valleys and ranges.

In broader regional terms, Rowley et al. (1978) extended the

Blue ribbon lineament of western Utah into Nevada to include the

Pioche mineral district. The zone is approximately 15 miles wide

and again is characterized by alignment of volcanic centers, east-

trending magnetic highs and hydrothermal alteration. North-

trending valleys and ranges are similarly terminated by the zone

and mountains south of the zone are topographically lower than

those to the north.

Aeromagnetic data examined by Stewart et al. (1977) indicate an

pattern of anomalies in the Great Basin, including one to

the south and another to the northeast of Caliente. These anomalies

apparently reflect intrusive bodies and are part of east-west

volcanic belts. Mineral deposits are found associated with these

east-west features (Shawe and Stewart, 1976).

Gravity data analyzed by Snyder (1983) reveals a distinct

gradient from Caliente south to the Morman mountains. Snyder

suggests that the gradient may reflect presence of a crustal shear

zone that has downthrown basement rocks to the north relative to strata south of the zone.

When combined, these independent studies present an east-west pattern of structural weakness in crustal material, thought to be a 16

right lateral shear zone, that divides the study area in the

vicinity of Caliente. The tectonic origin of this zone remains in

question though several theories have been postulated. Pertinent

to this study however, is merely the fact that the zone exists and

the question of possible effects on regional groundwater flow patterns. The presence of thermal springs discharging in Panaca

Valley and near Caliente may be due to enhanced porosity as a result of tectonic breakage, and barriers produced by fault gouge and offset of impermeable units.

HYDROLOGY

General Statement

Hydrologic data are relatively scarce within the study area, though some data are available from reconnaissance reports (Rush,

1964 and Rush and Eakin, 1963) and unpublished files of the U.S.

Geological Survey. Presently the aim is to provide available basic data and establish a fundamental hydrologic framework for the study area.

Surface Water

The Meadow Valley Wash drainage basin is tributary to the

Colorado River system. Generally, surface water flow is intermittent with peak flows occurring during spring snowmelt or as flash floods caused by summer thunderstorms. Discharge of Meadow 17

Valley Wash into the Muddy River occurs only during these peak flow

periods. Perennial surface water flow is confined to narrow

bedrock canyons including Eagle Canyon at the outlet of Spring

Valley, Condor Canyon at the outlet of Dry Valley and Cove Canyon

which drains Panaca Valley (Figure 2). Hamlight Canyon, which

drains Patterson Wash above Condor Canyon, is unique in that no

perennial surface water flow is observed.

Stream gaging sites have been periodically maintained at

several locations along Meadow Valley Wash and its tributaries.

Average annual discharge data is summarized in Table 1. It is

interesting that no flow is observed in 17 years of record from a

crest stage gage in a channel draining the Bristol Range into

Patterson Wash. Flow may be absorbed in alluvium on the fan though

carbonate rocks in the Bristol Range may also absorb streamflow.

Groundwater

Groundwater is utilized for irrigation, stock watering,

domestic and municipal purposes. Spring Valley, Patterson Wash and

the upper fans of Panaca and Lake Valleys are utilized for grazing

cattle. Irrigation withdrawals are by far the largest demand on the

groundwater resource. Principal irrigation districts are found in

southern Lake Valley, and along Meadow Valley Wash in Dry and

Panaca Valleys. Increasing rates of withdrawal in Panaca Valley have resulted in declines in water levels over the last 40 years

(Figure 5). In fact, the Nevada State Engineer's office lists ^ab^e Surface water data for upper Meadow Valley Wash, Data is derived from continuous record except as noted.

Avg. annual Period of Discharge Location Record Years (ac-ft/yr) Reference 1. Patterson Wash trib. near Pioche 1964-1981 17 0 * USGS (1981) 2. Meadow Valley Wash at Eagle Canyon 1962-1974 12 4970 USGS (1974) 3. Meadow Valley Wash at Condor Canyon 1945-1949 5 3400 Rush (1964) 4. Mathews Canyon Clover Valley 1958-1984 26 618 USGS (1984) 5. Pine Canyon Clover Valley 1958-1984 26 1440 USGS (1984) 6. Meadow Valley Wash S. of Caliente 1951-1983 26 8550 USGS (1983)

* above data derived from crest stage gage, which records only maximum discharge. Figure 5. Co mparison of wafe r tevefa h t wo observation wefls (US GS unpublished data) and esti m ated annual pu m page h Ftanaca V dey ( N evada State Engineers Office, unpublished data). Panaca Valley as a designated groundwater basin, limiting

additional development.

In addition to well pumpage groundwater is also used at natural

discharge areas. Spring discharge in northern Lake Valley and

Panaca Valley is diverted for irrigation. Several springs are

thermal m nature (>20 deg C) , and constitute a substantial

discharge (Table 2 and Figure 6). Most notable is Panaca Spring,

apparently discharging from a fault contact between alluvium and

carbonate rocks.

Water levels in selected wells were measured in the spring of

1985 by personnel of the U.S. Geological Survey. Detailed data for

these wells is listed in Appendix 1. Generally, groundwater

gradients are in the same direction as surface water drainage,

flowing from the mountains to the valleys and from northern valleys

toward the south (Figure 6).

Lake Valley is topographically closed by low divides at the

northeast and southern ends of the valley. Rush (1964) provides

water level data that indicates a hydrologic divide between Lake

Valley and Spring Valley to the northeast. Conversely, water level

data in Figure 6 indicates a gradient from Lake Valley south to

Patterson Wash. Water level data are not available to prove conclusively whether topographic divides, defining the remainder of the study area, constitute hydrologic divides. However, given an altitude of the divide ranging from 7000 to over 10000 feet above sea level, enough precipitation may be received to create an effective hydraulic divide. Numerous high altitude springs, though flOW by Garslde

flow name gpm date

Lake Valley

Geyser Sp 200 1950 3,4 Big Sp 2 2800 Augl963

Dry Valley

Flatnose Sp 400 Decl946 Delmues Sp 200 1948

Panaca Valley

46 Bennett Sp 10 1948 42 Panaca Sp 1800 1915 6200 1946** 3600 1948 4900 1963 4500 1985

** Measurement cited by Rush (1963) iue . tr ee3i fe aoesa ee wtv the wrttvi level sea above feet Ievei3,in ater W 6. Figure

AoW43 ^ td ae (SS upbihd data} unpublished (USGS, area study Well S ___ Miles rn ad ie number site and pring : 1 0 ______7S0vCO3 10 22 23

possibly perched, may testify to the well watered nature of the

mountain ranges bordering the study area.

AQUEOUS GEOCHEMISTRY

General Statement

Major ion geochemistry can be used, within a geologic and

hydrologic framework, to describe processes responsible for

observed groundwater chemistry and suggest mixing and evolutionary

relationships. Stable isotopes of oxygen and hydrogen can also be

used to establish mixing relationships as well as suggest sources

of recharge and detect evaporative effects.

A specific goal in analysis of geochemical data is

determination of whether local and regional flow conditions can be

distinguished. If a distinction can be drawn the degree of

interaction between the two systems is of further interest.

Geochemical processes that may explain spatial data are described and mass balance calculations, utilizing conservative constituents as tracers, are used to quantify and evaluate mixing of subsurface flow. 24

Major Constituent Geochemistry

Location of sampling sites is indicated in Figure 7. Site

numbers in Figure 7 correspond to site names, physical

characteristics and major ion analyses in Appendices 2 and 3.

Analyses have been plotted on a trilinear diagram to provide an

indication of general chemical character and detect possible trends

(Figure 8). Trilinear diagrams are prepared by plotting percentages of specific cations and anions, in equivalent units,

and thus do not represent concentrations or total dissolved solids.

Generally bicarbonate is the dominant anion, although some samples from irrigation wells in Panaca Valley contain sulfate as a co-dominant anion with bicarbonate. In contrast, basin fill samples from Lake Valley, Spring Valley and Patterson Wash contain a relatively high proportion of chloride in co-dominance with bicarbonate. The difference in co-dominant anions may reflect a difference in evaporite minerals present in lake sediments of

Panaca Valley compared to sub-basins to the north.

The cation portion of Figure 8 suggests a trend from calcium to sodium as the dominant cation. Magnesium content is fairly low along this trend except for a cluster of low sodium, relatively high magnesium samples. These sites correspond to samples collected from carbonate terrain and may reflect dissolution of dolomite. The trend from calcium to sodium includes high altitude springs as low sodium samples with an increasing proportion of 25

27

S°dIU” f ° " n d In “ 11 - P i - . Precipitation of calcic,

possibly including weathering or dissolution of minerals containing

sodium might explain this trend.

To further investigate processes responsible for major ion

chemistry, chloride concentration is plotted against other major

ions. Since chloride is highly soluble and not easily removed from

solution, comparison of chloride with other constituents can imply

processes controlling concentration of these constituents.

Plotting chloride versus calcium indicates a moderate increase

m calcium with increasing chloride concentration (Figure 9). The

data is compared to an arbitrary 1:1 line. If evaporation alone

were controlling concentration of these ions, the data should plot

along a 1:1 line. Presence of sources or sinks for either ion would cause a deviation from the 1:1 line. In this case, precipitation of calcite and/or dissolution of a chloride mineral may explain the data. Examination of Figure 10, comparing chloride and bicarbonate concentration, indicates a similar relationship.

Calculation of saturation indices, using the computer program

WATEQF (Plummer et al. , 1976), indicates that most samples are saturated with respect to calcite. Exceptions are dilute springs in volcanic terrain and some basin fill wells in Patterson Wash.

A plot of chloride versus magnesium indicates a cluster of samples containing relatively low chloride and high magnesium concentrations (Figure 11). These sites, as in the trilinear plot, correspond to spring samples from carbonate terrain. The remaining Calciu m, m eq/l tudy , an irary tl Una n U l t y r a bitr r a n a o t d e r a p m o c a, e r a y d u st 9. ids eddun for ter lesInthe h t n I s e pl m a s r e at w d n u o r g r o f n u d d e s u s r e v s d ri o H C . 9 e r u g n Valey lean r in ai err t o nt a e ol v y e all V r e v o D ❖ Valey in l, deg C g e d 0 2 > All, n si a b y e all V a c a n a P + Panaca l bas il deg C g e d 0 2 < fill, n si a b y e all V a c a n a P X a Pate Wa ca te r in n ai err t e at n o b ar c h as W n o s er att P A r Valey lcan r in n ai err t c ni a c ol v y e all V g n pri S O • S pri n g V all e y b a si n fill n si a b y e all V g n pri S • Lake l vo fa r in ai err t a nf a o ol v y e all V e k a L □ La Voley in l All n si a b y e oll V e ak L ■ P att er s o n W as h b a si n fill n si a b h as W n o s er att P 8 2 Bicarbonate fti e st u d y a r e a, c o m p a r e d d e r a p m o c a, e r a y d u st e fti Fi g u r e e r u g Fi X X C hl o ri d e v e r s u s s u s r e v e d ri o hl C C Valey lcan r in ai err t c C ni g a e c d ol 0 v y 2 C > e all g fill, V e n el d r e a 0 b v 2 o y < e Cl flll, n all el V a a b c a y e n ❖ all a V P a c a n + a P X a Pote Waeh rbona tera n ai err t e at n o b ar c h e a W n o e er ott P A r Voley lcan r in n ai err t c ni a c ol v y e fill n oll V at o g b n y pri e all S V g n O pri S • Loka l vo ic r in ai err t c ni a c ol v y fill n e oll el a V b a k y o e all L V e k a □ L ■ P ott er e o n W a e h b a si n fill n si a b h e a W n o e er ott P lanaion o ati n a pl x E i rbona e at n o b ar bic o t loide meq/I e m e, d ori hl C a n n a rbt ry y ar bitr ar f o r g r o u n d w at e r s a m pl e s s e pl m a s r e at w d n u o r g r o f l e. n li l t n i 9 2 Magnesiu m! meq/l igure Ch ide magnes groundwa samp n I s e pl m a s r e at e. w n li d l t n y u r a o r bitr g r a r o f m m o u t si d e e n r a g p a m m o s c u s a, r e e r v a e y d ri d o u hl st C e 1 1 h t e r u g Fi C Valey lcan tera n ai err t c ni a c ol v y e all V r e v o Cl ❖ Valey in si a b y e all V a c o n a P + Pate Woeh in si a b h e o W n o s er X att P * A r Valay lcan tera n ai err t c ni a c ol v y a all V g n pri S O Sping l bas mi n si a b y a oll V g n pri S • Lake lk vo ic t in ai str t c ni a c ol v y ki al fill n V si a e k b a y L e all V e ak □ L ■ Pots Wa ea ts t in ai atr t s ot n o b ar e h as W n o s sr ott P Valey in si a b y e all V a c o n a P i > 0 2 > mi, i 0 2 < mi, mi C C g e d g e d C 0 3 31

data plot near a 1:1 line, apparently not moderated by the same

process controlling calcium a„d bicarbonate conoantratlon

Alignment of the data in Figure 11 along a 1:1 U ne may suggest

evaporative concentration, though mixing may explain some data.

Basin fill stock veils in Patterson Hash plot at a lover

concentration of chloride than an irrigation well in southern Lake

Valley located upgradient. Mixing of Lake Valley alluvial outflow

with recharge from adjacent mountain ranges may account for

chemistry in the Patterson Hash wells. If mountain springs are

assumed to be indicative of recharge chemistry, springs from

IfiKhwI- volcanic terrain in southern Lake Valley and carbonate terrain in Ibksm Patterson Hash may provide an end member for mixing with Lake ijrirJ Valley outflow (Figure 11) . ISSi-lU'

Comparing plots of chloride versus sulfate and sodium jJMRl'fi*

respectively (Figures 12 and 13), most data appear to plot near a

1:1 line, although low sodium samples at a moderate chloride ffjl

concentration plot below the line (Figure 13). Cursory evaluation

of these plots might suggest evaporation as a mechanism for an apparent 1:1 increase in concentrations.

Springs from carbonate terrain, identified as a group in previous plots, contain low concentrations of sulfate and sodium as well as chloride. In comparison, springs from volcanic terrain generally contain higher concentrations of chloride and variable concentrations of sulfate and sodium.

Most thermal springs plot as a distinct cluster, above the 1:1 line in Figure 13. This distinction may reflect a different source S ulf at e lgfB 12 Ch ide sifafe for ter lesin i s e pl n x c s r e at w d n u o r g r o f e f a iif s s u s r e v e d ri o hl C 2. 1 B gif Fl s oea, cn irary Une. n U l t y r a bitr r a n c o t d e r a p m o c , a e o y d u st e h t Cover l vo ictera n ai err t c ni a c ol v y e all V r e v o C ❖ Valey infl, 20 C g e d 0 2 C > g fill, n e si d a 0 b 2 < y e fill, n all si V a a b c y a fill n e n si all a a V b P h a c as o W n + a n P o s er att X P * Pate Wa ca te r in ai err t e at n o b ar c h as W n o s er att P A r Voley lcan tera n ai err t c ni a c ol v y e oll V g n pri S O Sping l bas fill n si n a ai b err y t e c oll ni V a c g ol n v pri y S e all V e k • o L □ L Valey infl fill n si a b y e all V e k La ■ 2 3 S o di u m tudy , an irary Iha h I l t y r a bitr r a n a o t d e r a p m o c a, e r a y d u st igure . lor versus ium for ter les r s h t fri s e pl m a s r e at w d n u o r g r o f m u di o s s u s r e v e d ri o hl C 3. 1 e r u g Fi Valey in i, deg n ai C err g t c e ni d 0 a 2 c > ol Til, v ( n y si e a all b V y r e e all v V o Cl a c a > n < a P + Panaca l bas (Tl < Til, ( n si a b y e all V a c a n a P X a Pate Wash rbona tera n ai err t e at n o b ar c h s a W n o s er att P A r Valey lcan tera n ai err t c ni a c ol v y e all V g n pri S O Sping l bas ilfill n si n a ai b err y t e c all ni V a g c ol n v pri y S e all V e k • a L □ Valey in l All n si a b y e all V e k a L ■ Pate Wa bae All, n et a b h as W n o s er att P 4*3 0 2 C C 3 3 34

for sodium in solution thsn other groups of sables. Thermal water

is probably derived from flow along fractures and solution channels

in consolidated rocks, and may obtain sodium from weathering or

dissolution of feldspars or cation exchange rather than dissolution

of evaporite minerals.

The mixing relationship previously suggested for Patterson Wash

wells is also illustrated in Figure 12. Again, the basin fill

wells plot between a Lake Valley irrigation well and springs from

adjacent mountain ranges. This mixing relationship appears to

include some mechanism for removal of sodium as indicated by Figure

13. Site 5, an irrigation well in southern Lake Valley, plots near

irrigation wells in Panaca Valley. Site 21, immediately

downgradient from site 5, contains a lower concentration of

chloride and a much lower concentration of sodium. Since no low

sodium end member is apparent, sodium must be removed from solution by some mechanism, possibly adsorption. Further downgradient,

chloride continues to decrease. Sodium remains constant to site

23, then shows an increase by site 24. This trend may reflect a progressively more dominant influence of local recharge downgradient in Patterson Wash. Site 24, located near the terminus of Patterson Wash, plots closer to spring samples from adjacent mountain ranges than samples upgradient.

Panaca Valley irrigation well samples, containing relatively high concentrations of chloride, plot near the 1:1 line in Figures

12 and 13. Evaporation may be likely in this group of samples given a shallow water table (< 50 feet) and the dominant water use. 35

Stable isotope data will be used t-n confirm or disprove the occurrence of operation. Becauee of „,.«quilIbrl„

fractionation that occurs during evaporation, stabie isotopes of

oxygen and hydrogen are ideally suited for detection of evaporation.

On a plot of 5 0 versus 5 D evaporated samples would be

expected to plot to the right of the global meteoric water line of

Craig (1961), along a flatter slope. Most data in Figure 14 plot

along the Craig line. The only samples that appear as if they may

have been evaporated are sites 16 and 22. Site 16 is a surface

water sample collected at the outlet of Spring Valley. Another

surface water sample, site 11, was collected on the same day near

the head of Spring Valley, upgradient of site 16. Sites 16 and 11

therefore, may define an evaporation trend. Site 22 is a low flow

spring, located at a relatively low altitude near the divide between Lake Valley and Patterson Wash, and plots to the right of sites 6-9, which are higher flow springs located at a higher altitude. No clear evaporation trends are seen in Panaca Valley samples. -

Plotting chloride versus & D can also serve to identify evaporative concentration. Strict dissolution as a means of concentration of ions should plot as a straight line with increasing chloride at a constant S D value. Evaporation will cause an increase in c .loride concentration and enrichment in 5 D due to fractionation. The resulting theoretical plot is a curve del 0 xygen-*18 perm il

Explanation ■ Late Valley baaln Till □ Late Vailay volcanic and doolie terrain # Sprinf Valley baetn ITU O Spring Valley volcanic terrain A Patterson Wash carbonate terrain a Patterson Waaft baaln All X Panoea Valley

Figure K Del Qxygen-C versus del Deuierim fcr groundwaier end surface wafer samples in the study area 37

expressed by a rearrangement of the Rayleigh distillation equation

(Fritz and Fontes, 1980):

(1) 5 D = (5 + 1000)f^a ^ . 1000

where 5 Dq = initial deuterium concentration permil

f "" fraction of initial volume remaining

a = fractionation factor

Figure 15 illustrates a dissolution trend between springs in

northern Lake Valley (sites 3 and 4) and an irrigation well in

southern Lake Valley (site 5). Also indicated is a mixing

relationship between the irrigation well and mountain springs in volcanic terrain of southern Lake Valley (sites 6,7,8 and 9), with

site 21 plotting at an intermediate position. This relationship appears to confirm a postulated mixing scenario previously based on strictly chemical data.

In a similar chloride versus S D plot of Panaca Valley data an interesting relationship is observed (Figure 16). The data appear to form a curve possibly suggesting evaporative concentration.

However, comparison with a theoretical evaporation curve indicates that the data lie below the curve (Figure 16) . The theoretical curve was calculated using equation 1 and assuming a fractionation factor of 1.0074. Using a fractionation factor of 1.074, which is estimated for equilibrium conditions at 25 deg C (Fritz and Fontes,

1980), results in an even poorer match between the curve and observed data.

Examination of individual data points in Figure 16 reveals an alternative interpretation. Site 40 is located immediately F igure 15. Chloride versus del Deuterium for ground water samples In Lake Valley. Figure 16. Chloride versus del Deuterium for Panaca Valley sites and Cdlente thermal water. 40

downgradient from Panaca Spring (site 42), and appears to mimic the

isotopic composition, chemistry and temperature of the spring.

Site 39, located upgradient of the spring near the mouth of Condor

Canyon, is isotopically heavier, 7 degrees C cooler and contains a

higher chloride concentration than the spring. This site may

reflect local flow, largely recharged by infiltration of Meadow

Valley Wash. If site 39 is presumed to be a local end member, site

36 may be explained by mixing of this local flow with regional

discharge from Panaca Spring. Sites 37 and 38, located furthest

from the spring, may be explained by simple dissolution, reflecting

flow genetically similar to site 39, apparently unaffected by

discharge at Panaca Spring.

In considering mixing end members in Panaca Valley, a potential

complication lies in the relationship of Panaca Spring to Caliente area thermal water. Site 45 represents a thermal sample from a well near Caliente (Figure 16). If there is a link between Panaca spring and Caliente thermal water, it appears that Caliente thermal water may represent an end member and Panaca Spring may be mixed with a small fraction of local flow. Alternatively,

Caliente thermal water may simply represent deeper circulation than

Panaca Spring. Rather than a well mixed regional reservoir flow may be stratified. Since there is no surface discharge of Caliente thermal water the magnitude of this flow is unknown.

Interpretation of a relationship with Panaca Spring is tenuous at best, thus Panaca Spring is considered the primary point of regional discharge. 41

Chloride balance

The spatial distribution of chloride concentration is provided

in Figure 17. Most mountain springs are characterized by low

chloride concentrations ranging from 4 to 12 mg/1 . Springs in

volcanic tuff of the White Rock Mountains are an exception, with

concentrations ranging from 19 to 23 mg/1. Within basin fill

samples, relatively high chloride concentrations are found in a

Spring Valley stock well (51 mg/1), and a southern Lake Valley

irrigation well (68 mg/1). Panaca Valley samples range from 16 mg/1 at Panaca Spring to 282 mg/1 at a basin fill observation well.

As previously described, a trend of decreasing chloride concentration downgradient is seen in Patterson Wash. A decline from 68 mg/1 in southern Lake Valley to 19 mg/1 near Pioche occurs.

Possible explanations for this trend include hydraulic isolation of sampling points, perhaps by a stratified aquifer system or dilution, either by upward flow from underlying carbonates or from recharge in adjacent mountain ranges. Since the decline along the wash is continuous despite differing well depths, distinct stratified aquifers do not seem likely. Dilution appears to be a tenable explanation for the trend. Since there is no data that demonstrates a vertical gradient in a carbonate aquifer an attempt will be made at modeling dilution in Patterson Wash by mixing Lake

Valley subsurface outflow with low chloride recharge waters.

The wash was divided into sub-drainages, such that boundaries intersected wells in the wash (Figure 18). Recharge estimates were 42

Figure 17. Spatial dstrflxiticn of chloride concentration in mg/L within the study area 43

FTgura 18. Division of sutJ-drainage3 and associated chloride concentrations in Patterson Wash 44

then determined for each sub-drainage. An empirical method known

as the Maxey-Eakin method has been used to estimate recharge rates

(Maxey and Eakin, 1949). Recognizing dependence of precipitation

on altitude, this method assumes that within specified altitude

zones, a fixed percentage of precipitation results in recharge.

Average annual precipitation estimates and percent resulting in recharge are the same as used in reconnaissance water budget calculations by Rush (1964).

Percent Altitude Avg. annual equaling (feet) precip. (feet) recharge >9000 1.75 25 8-9000 1.46 15 7-8000 1.12 7 6-7000 0.83 3 <6000 0.50 0

Statistical analysis of the Maxey-Eakin method by Watson et al.

7 6) suggests marginal reliability of the technique and emphasizes the non-unique nature of the solution. However, the authors concede that no other practical method exists for estimating recharge at a regional scale in Nevada.

Chloride balance calculations that follow are largely based on reconnaissance water budgets for Meadow Valley Wash (Rush, 1964) and Lake Valley (Rush and Eakin, 1963). These budgets utilize

Maxey-Eakin recharge estimates and discharge measurements and estimates. An assumption of a single aquifer system is implicit in these reconnaissance calculations.

Since refinement of these reconnaissance water budgets is desired the study area has been divided into four compartments. 45

Within each compartment distinction is drawn between dominantly

carbonate and non-carbonate lithology of recharge zones (Table 3).

Irrigation withdrawal estimates for Panaca and Dry Valleys are

derived from 1985 crop inventories by the Nevada State Engineer's

office. Other withdrawal estimates are derived from the two

reconnaissance reports listed above. Recharge estimates were

determined using a planimeter and a 1:250,000 scale topographic map

to determine areas within altitude zones and then applying the same

precipitation estimates and subsequent percent resulting in

recharge as those used in- the reconnaissance reports.

As indicated in Table 3, Rush and Eakin (1963) estimate that

3000 ac-ft/yr (acre-feet/year) of groundwater exits southern Lake

Valley at a cross section measured at the topographic divide, which

incidentally intersects the location of site 21 (Figure 18).

Recharge between site 5 and site 21 is estimated at 1350 ac-ft/yr.

The difference between this recharge and estimated flow at site 21

(3000 ac-ft/yr) is assumed to represent the flow at a cross section

through site 5 equaling 1650 ac-ft/yr. Beginning with this initial

flow of 1650 ac-ft/yr at a chloride concentration of 68 mg/1,

recharge weighted by an average chloride value will be mixed within

sub-drainages resulting in. predicted chloride values at points

along the wash, represented by equation 2. Implicit in these calculations is the assumption that dissolution of chloride minerals is negligible, consequently predicted chloride concentrations probably represent minimum values.

(2) C = S Q.C. m i. -1 l i

L-s I Q,1 Table 3 . Reconnaissance water budget, in ac-ft/yr, for the Meadow Valley Wash Area, after Rush (1964) and Rush and Eakin (1963).

Recharge Discharge

Lake Valley

Carbonate Evapotranspiration (ET) 8500 Southern Schell Cr Subsurface outflow 3000 and northern Fortification ranges 5000 Non-carbonate Northern Schell Cr, southern Fortification and north Wilson Cr ranges 8000

Spring Valley

Non-carbonate ET 1000 Wilson Cr and White Average annual surface Rock ranges 10000 water discharge 5000

Patterson Wash

Non-carbonate West Wilson Cr Range 4000 Carbonate Bristol/Highland Range 2000

Panaca and Dry Valleys

Non-carbonate Pumping 14000 Mahogany/Cedar Ranges 4000 Panaca Sp discharge 8000 ET 2000 47

where flow rate in ac-ft/yr from the ith source

^ ~ concentration of the ith source

— predicted concentration in the mixture.

Results from these calculations for five wells along Patterson

Wash are summarized in Table 4. Four of the five predicted concentrations are within 10 percent of observed data. Site 23

indicates a predicted concentration 8 mg/1 or 33 percent higher

than the observed chloride concentration.

Extending chloride observations in Patterson Wash to include

site 42, Panaca Spring, one notes a chloride concentration of 16 mg/1 at the spring compared to a range of 18 to 21 mg/1 in wells near Pioche (sites 25-27). Again, low chloride recharge received between these two points may account for dilution if the waters are hydrologically connected. A potential source of recharge lies in

the Highland Range where average annual recharge is estimated at

1200 ac-ft and chloride concentration in three springs averages 4 mg/1 (Figure 17). If this flow is mixed with a cumulative flow in

Patterson Wash of 7600 ac-ft/yr a total flow of 8800 ac-ft/yr at a chloride concentration of 18 mg/1 is calculated, which closely approximates the value observed at Panaca Spring (Table 4).

Another source of recharge that could contribute to flow between the terminus of Patterson Wash and Panaca Spring is found in the Mahogany and Cedar Ranges. Recharge in these mountains is estimated at 4000 ac-ft/yr, although three mountain springs in the area, sites 13, 31, and 55, have chloride concentrations ranging from 19 to 29 mg/1 (Figure 18). If these concentrations are Table 4. Summary of chloride balance calculations for Patterson Wash.

Assumed Site Flow Cl(mg/1) Cumulative Predicted Observed n o . ac-ft/yr in recharge flow Cl mg/1 Cl mg/1

5 1650 - - - 68

21 1350 7* 3000 41 44

23 1060 7* 4060 32 24

24 2150 7* 6210 23 21

7* 25-27 1410 7620 20 19

42 1200 4** 8820 18 16

* Average chloride concentration for high altitude sites in Spring Valley and southern Lake Valley.

** Average chloride concentration for high altitude sites in the Highland Range. 49

indicative of recharge, then this source of water has a chloride

concentration too high to cause a dilution of flow in Patterson

Wash.

The difference of 8 mg/1 between predicted and observed

chloride concentrations at site 23 may be explained by assuming

higher recharge rates or lower chloride concentrations in recharge

Alternatively, the difference may be explained by a more complex

flow system than the simple one layer, well mixed configuration

described thus far. The system may include a local basin fill

aquifer underlain by a regional carbonate aquifer as suggested by

Rush (1964). If a two layer flow system is assumed, interaction

between the two aquifers may account for the generally higher

predicted chloride concentrations than observed in the basin fill

wells.

Assuming an upward vertical gradient from a regional aquifer,

the upward leakage rate required, in addition to mountain recharge,

to account for the chloride concentration at site 23 can be

estimated. Chloride concentration in the regional system is

assumed to be 6 mg/1, reflecting the concentration of sites 3 and 4

in upper Lake Valley which is assumed to represent input

concentration to the regional aquifer. Recharge has been divided

into carbonate and non-carbonate estimates based on lithology of

the mountain blocks considered. Results, summarized in Table 5,

indicate that 2300 ac-ft/yr of upward flow between sites 21 and 23

is required to achieve the observed chloride concentration at site

.23. Subsequent mixing of the cumulative basin fill flow at site 23 50

Table 5. Summary of chloride balance calculations for Patterson Wash oasin fill, as suming a two layer system with a vertical gradient.

Assuming upward vertical gradient site non-carbonate leakage cumulative predicted observed n o . recharge rate flow Cl mg/1 Cl mg/1 Ac-ft/yr Ac-ft/yr Ac-ft/yr

21 1350 3000 41 44 23 1060 2300 6360 24 24 1650 8010 20 21 25-27 1100 9110 19 19

Assuming downward vertical gradient site non-carbonate leakage cumulative predicted observed n o . recharge rate flow Cl mg/1 Cl mg/1 Ac-ft/yr Ac-ft/yr Ac-ft/yr

21 1350 3000 41 44 23 1060 -2100 1960 24 24 1650 3610 16 21 25-27 1100 4710 14 19 51

with non-carbonate recharge produces a near perfect match of

predicted and observed chloride concentrations at the remaining two

sites downgradient (Table 5).

Assuming a downward vertical gradient and solving for the

leakage rate of relatively high chloride basin fill groundwater

needed t_o achieve a match at site 23, yields an estimate of 2100

ac-ft/yr. This scenario, summarized in Table 5, requires leakage

of high chloride basin fill flow, between sites 21 and 23, prior to

mixing with low chloride recharge. Mixing the remaining basin fill

flow at site 23 with mountain recharge results in predicted values

at the two sites downgradient. In this case, predicted

concentrations are up to 24 percent lower than observed data (Table

5).

It appears that an upward vertical gradient provides the best

fit of predicted and observed data. However, the fate of

cumulative basin fill flow in Patterson Wash needs to be addressed.

As Rush (1964) observes, no significant natural or artificial

discharge occurs in Patterson Wash, nor is any perennial flow seen

in the bedrock canyon draining the wash. Given this observation, leakage or reduction of basin fill flow along the wash seems more logical than upward flow and an increasing basin fill flow rate along the wash. A downward leakage scenario results in a cumulative flow of 4710 ac-ft/yr in basin fill at the terminus of the wash. In comparison, an upward leakage scenario yields a cumulative flow rate of 9110 ac-ft/yr in basin fill. Since the cumulative basin fill flow in Patterson Wash appears to 52

exit the basin via fractured volcanic rocks, a downward leakage scenario, resulting in a lower flow rate, seems more reasonable.

The three scenarios outlined above suggest quite different sources for regional discharge at Panaca Spring. A single layer system, defined in Table 4, suggests that cumulative flow in

Patterson Wash is the primary source for discharge at Panaca

Spring. In contrast, a two layer system with upward leakage results in the following regional budget and predicted chloride concentration:

Ac -ft/yr mg/1 Lake V. carbonate recharge 5000 6 Upward leakage -2300 6 Bristol/Highland Range rech. 2000 4

Total flow 4700 Weighted mean Cl concentration 5 mg/1

Since the total flow at Panaca Spring is 8000 ac-ft/yr and the chloride concentration is 16 mg/1, this scenario requires an additional source of 3300 ac-ft/yr at a chloride concentration of

32 mg/1 to achieve a match at Panaca Spring. Local basin fill flow may provide the high chloride source though a 60/40 mix of regional and local flow probably would not account for the thermal character of Panaca Spring.

A downward leakage scenario results in the following predicted regional flow and chloride concentration: Ac-ft/yr mg/1 Lake V. carbonate recharge 5000 6 Basin fill leakage 2100 44 Bristol/Highland Range rech. 2000 4

Total flow 9100 Weighted mean chloride concentration 14 mg/1

This scenario results in a reasonable comparison of predicted flow

rates and chloride concentrations with that observed at Panaca

Spring.

It should be noted that assuming a dominant source of regional

flow in Lake Valley, as required by the two layer system, results

in an imbalance in the reconnaissance water budget for Lake Valley

summarized as follows:

Ac-ft/yr Recharge 13000 E-T -8500 Basin fill outflow -3000 Carbonate outflow -5000

Sum -3500

Evapotranspiration studies in central Nevada suggest that early

reconnaissance estimates provided here are minimum values (Rita

Carman, personal communication) . Thus to achieve a balance it must be assumed that recharge in Lake Valley is approximately 30 percent higher than calculated by the Maxey-Eakin method. The uncertainty

in the Maxey-Eakin method is unknown, though an error of 30 percent

does not seem unreasonable. 54

Deuterium Balance

In general stable isotopes of oxygen and hydrogen vary from north to south with more depleted samples found farthest north

(Figure 19) . Valley floor springs and an irrigation well in Lake

Valley have 5 D values of -111, -112 and -111 permil respectively.

Springs and wells in the Clover Mountains near Caliente range in 5

D from -86 to -95 permil. Thermal waters in Panaca Valley range in

5 D from -101 to -109 permil with the lightest values found in the

Caliente geothermal area.

In an effort to more fully delineate subsurface flow in the area, deuterium will be used with recharge estimates, as was done with chloride, to construct a water budget. This approach requires the same set of assumptions as previous chloride calculations: 1) the Maxey-Eakin method can be used to estimate recharge; 2) high altitude springs can be considered representative of recharge; and

3) the tracer, in this case deuterium, is conservative. The Maxey-

Eakin method has been discussed previously. Whether high altitude samples reflect recharge cannot be strictly proven, though low chloride concentrations and lack of evaporation are taken as evidence supporting this contention.

The conservative nature of deuterium is critical to the following analysis and requires discussion. Conditions that may violate this assumption include fractionation or exchange of isotopes subsequent to recharge or variation of the isotopic composition of recharge within the residence time of the aquifer. 55 56

It is generally assumed that once water is recharged physical and biological processes that may produce fractionation in the near

surface environment are not effective at depth . For example,

evaporation can cause fractionation at or near the surface but

generally is not a factor at depth.

Variation of the isotopic composition of recharge through time

may occur due to differing paleoclimatic conditions, that is a

cooler climate, during glacial periods, would be expected to yield

isotopically depleted recharge relative to current recharge.

Examination of ice cores, deep sea drilling samples, and

speleothems have demonstrated this variation in a variety of

studies (Buchardt and Fritz, 1980; Harmon et al., 1975, 1979;

Berger et al. , 1982). Recent work in southern Nevada by Claassen

(1983), and Winograd et al., (1985), further imply a connection

between paleoclimatic conditions and the isotopic composition of

meteoric water. Claassen (1983) presents a plot of 5 D versus

carbon 14 derived age date and compares the data to estimates of

departure from mean annual temperature over time. A correlation

between glacial-interglacial fluctuation and the isotopic

composition of recharge is suggested by Claassen. In contrast,

Winograd et al. (1985) call upon tectonic uplift of the Sierra to

account for non-cyclic depletion of deuterium with age of fluid

inclusions in calcitic veins in the Ash Meadows area of southwest

Nevada.

Previous studies, though not conclusive, do suggest variation

in the deuterium content of recharge over time. Assuming 57

paleoclimatic induced variation does exist in Nevada waters, the

question of whether discharge samples collected are old enough or have mixed with water of sufficient age to reflect paleoclimatic

conditions remains. Since no age dates are available for sites

sampled within the study area correlation of observed deuterium values and age dates with glacial cycles is not possible. Despite

this lack of data an attempt will be made to address this potential

source of uncertainty, though initial analysis will be based on an

assumption of time invariance of deuterium content in recharge.

In constructing a deuterium balanced water budget,

representative deuterium values need to be assigned to recharge

zones. One approach is simply to use a mean value of available

sites within the zone. However, inconsistencies require further

examination.

5 D for sites in northern Lake Valley range from -105 to -112

permil (Figure 19). Two valley floor springs, sites 3 and 4, are

calcium-bicarbonate, low chloride waters that appear to discharge

along a range front fault. These springs are described as thermal by Garside and Schilling (1979), temperatures of 18.5 and 20.5 deg

C were measured by the author during sampling. The springs have 5

D values of -111 and -112 permil, and probably reflect local flow conditions, as suggested by Mifflin (1968). An irrigation well in southern Lake Valley, site 5, also has a 5 D value of -111 permil, and represents flow in the basin fill. In comparison, two high altitude springs in the Schell Creek Range, sites 1 and 2, have 5 D values of -105 permil. No evaporation is indicated for these two 10 sites on Figure 14. The uniformity of deuterium content in spatially distinct sites on the valley floor suggests that -111 permil may be a representative value of recharge to Lake Valley.

The high altitude springs may reflect a localized precipitation event rather than typical recharge to the basin. Though it is interesting that both springs have identical deuterium values yet one is at an altitude of 6200 feet and the other 8200 feet. Unless the springs were fortuitously recharged at the same altitude a lack of correlation of altitude with isotopic composition is implied.

It is possible that an external source of recharge to Lake

Valley is responsible for the light values observed in the valley.

However, there is no data available to suggest an interbasin transfer of water into Lake Valley. Water level data from the alluvial aquifer indicates a hydrologic divide bounding northern

Lake Valley and subsurface outflow from southern Lake Valley toward the south (Rush and Eakin, 1963).

Labelling subsurface outflow from Lake Valley to Patterson Wash is of primary interest in constructing a deuterium balanced water budget. Site 21, located near the topographic divide between Lake

Valley and Patterson Wash, has a 5 D value of -107 permil.

Previous chloride mixing calculations suggest dilution of Lake

Valley outflow with local recharge. Using the same flow and recharge estimates for site 5 and 21 as listed in Table 4 and substituting 8 D values for chloride concentrations results in the following calculations:

(3) QiCj + Q2C2 = C3

Qs 59

1650(-111) + 1350(-100) = -106 permil

3000

where Qj = flow in ac-ft/yr at a cross section through site 5 . Q 2 = estimated recharge between site 5 and site 21. Q3 = cumulative flow at site 21. Cx = observed 8 D permil at site 5. C2 = average 8 D permil of sites 6,7,8 and 9. C3 = predicted 8 D permil at site 21.

A close match between a predicted 5 D value (-106) and an observed value (-107) at site 21 confirms a mixing scenario and may suggest

that -107 is a representative 5 D value for subsurface outflow from

Lake Valley.

Spring Valley presents a similar dilemma as found in Lake

Valley in that a surface water sample and valley stock well, in the

upper reach of the valley, are isotopically light relative to

adjacent mountain springs. Again, no evaporation trends are

clearly evident on Figure 14 that may explain the relatively heavy-

composition of the springs.

A range of 8 D from -97 to -103 permil is found in the Highland

Range. Sites 18 and 44 are thermal (> 20 deg C) and are very

similar chemically, though site 44 has higher concentrations of

chloride and sulfate. Site 44 discharges along an apparent fault

contact on the upper fan and has a 5 D of -103 permil. In

comparison, site 18 is located at a higher altitude and has a 8 D

of -97 permil. The remaining springs are also located higher than

site 44 and have 8 D values of -98.5 and -99 permil. Both warm

springs appear to be locally derived based on low Cl + S04 and Na + 60

K concentrations (< 1 epm) and their relatively high altitude locations. Again, the explanation for a heavier isotopic composition of the higher altitude springs is unclear.

Lack of available data in the Cedar and Mahogany Ranges requires interpolation between adjacent ranges. A spring in the southern White Rock Range and a well in upper Clover Creek Valley both have S D values of -95 permil. This value will be assumed to be indicative of recharge from the Cedar and Mahogany Ranges.

As an initial approximation of the water budget for upper

Meadow Valley Wash, the reconnaissance budget of Rush (1964) will be tested using assigned deuterium values. Considering total recharge to Panaca Valley, as listed by Rush, the following mixture results:

Ac-ft/yr S D permil Lake Valley outflow 3000 -107 West Wilson Creek Range 4000 -93 to -102 Bristol and Highland Ranges 2000 -97 to -103 Spring Valley 10000 -93 to -102 Cedar and Mahogany Ranges 4000 -95

Total flow 23000

Weighted mean 5 D value 96 to -102 permil

Comparing this predicted range to observed values in Panaca Valley

ranging from -101 to -109 permil suggests that this scenario does

not adequately describe the flow system given the assumptions

involved in assignment of deuterium values.

Instead of an even mixture of all available recharge, the flow

system is probably a combination of local and regional systems as

suggested by Mifflin (1968). It appears that discharge can, in 61 10 some instances, be distinguished on this basis. For example, sites

3 and 4 in Lake Valley were classified by Mifflin as local based on low Na + K and Cl + S04 concentrations (< 1 epm) . Similarly, site

44 in the Highland Range though thermal is also probably locally derived given low Na + K and Cl + S04 concentrations, low flow rate and chemical similarity to cold springs upgradient. In contrast,

Panaca Spring was classified as regional by Mifflin based on a tritium content of less than 8 T.U. (tritium units), warm temperature, a large discharge rate and Na + K and Cl + S04 concentrations greater than 1 epm. The goal in the following analysis is to determine source areas for the regional discharge I v, !!?■:• I ||||| seen at Panaca Spring and distinguish local and regional recharge.

Based on physical characteristics and previous chloride !]!!»;.

.ii calculations, flow into Patterson Wash and adjacent recharge may be the dominant source area for regional flow. To test this hypothesis, recharge from Spring Valley and the Cedar and Mahogany i||I|g

Ranges will be excluded from the regional mix. Though tenuous an ■p i

additional rationale for excluding these sources may be derived

from geologic considerations. The Cedar and Mahogany Ranges and

the mountains enclosing Spring Valley are composed of welded and

non-welded volcanic tuff and rhyolite. Rush (1964) describes these

strata as having a generally low hydraulic conductivity. However,

Winograd (1971) and Winograd and Thordarson (1975) demonstrate the

presence of relatively high conductivity /olcanic strata on the

Nevada Test Site. Hydraulic conductivity in volcanic tuffs was IK K found to be dependent on degree of welding with non-welded tuffs 62

acting as aquitards and welded tuffs capable of transmitting water via vertical joint sets. Because of the apparent lack of vertical and lateral continuity in hydraulic conductivity in tuffs, it may be reasonable to assume that percolating waters are impeded from entering a deep regional flow system.

Excluding Spring Valley and recharge from the Cedar and

Mahogany Ranges, and assuming that inputs to Patterson Wash contribute to regional flow results in the budget in Table 6 .

Again, the predicted regional range of -99 to -104 permil is heavier than the observed average of two samples from Panaca

Spring, at -107 permil (Table 6). Local flow calculations result in a reasonable approximation of predicted and observed values.

Considering the regional budget, it is obvious that an isotopically lighter source of recharge is required to achieve the composition observed at Panaca Spring. Two alternatives may be pursued: 1) there may be a dominant input from carbonate mountain blocks in Lake Valley at a S D value of -111 permil; or 2) the observed isotopic data at Panaca Spring may reflect recharge received during a cooler, wetter climate than present conditions.

These alternatives will be considered in turn.

The budget in Table 6 assumes that regional flow at Panaca

Spring is derived from an even mixture of inputs to Patterson Wash and that there is free communication between basin fill aquifers and an underlying carbonate aquifer. This scenario further requires that cumulative flow in Patterson Wash exits the basin via carbonate rocks, subsequently discharging at Panaca Spring. If a 63

Table 6 . Deuterium balance calculations for inflows to regional and local flow systems within the study area.

Regional ac-ft/yr 8 D permil

Lake Valley subsurface outflow 3000 -107 Wilson Creek Range 4000 -93 to -102 Bristol and Highland Ranges 2000 -98 to -103 predicted 9000 -99 to -104 observed 8000 -107 lllll;

Local

Spring Valley surface outflow 5000 -93 to -102 Cedar and Mahogany Ranges 4000 -95 Panaca Spring discharge 4000 -107 2 predicted 13000 -98 to -101 observed -101 3

1. Average S D value of two samples from Panaca Spring. 2. Rush (1964) estimates half of Panaca Spring flow recharges shallow aquifers. 3. 5 D value of site 39, considered representative of local flow from previous chloride versus 8 D plots. 64

stratified aquifer system is proposed, as was done in previous chloride calculations, then a proportion of recharge from mountain blocks in Lake Valley may circulate to depth and not be represented by shallow basin fill wells. Assuming that regional recharge occurs only in carbonate mountain blocks adjacent to Lake Valley and Patterson Wash (Table 3), a total flow of 7000 ac-ft/yr is estimated. If Lake Valley recharge is assigned a value of -111 and the Bristol and Highland Ranges values from -97 to -103 permil, then a range of predicted 5 D values from -107 to -109 is calculated.

If, in addition to carbonate recharge, leakage of basin fill flow in Patterson Wash is assumed, as proposed in previous chloride balance calculations, the following regional budget is produced:

Ac-ft/yr 8 D permil Lake Valley carbonate recharge 5000 -111 Basin fill leakage 2100 -107 Bristol/Highland Range rech. 2000 -97 to -103

Total flow 9100 Weighted mean 8 D -107 to -108

This scenario provides sufficient flow to account for discharge at

Panaca Spring and yields a match of predicted and observed 8 D values.

A second alternative for explaining isotope data in the regional system is to assume a single layer flow system in , but also Patterson Wash, similar to that given in Table 6 paleoclimatic including a paleoclimatic shift. As sximing that a shift would affect the most distal source, Lake Valley outflow, the 65

sno V magnitude of shift required can be calculated by solving for the 5

D value of this source in equation 2. If flow rates in Table 6 are assumed and the lightest observed values are assumed to represent recharge from the Wilson Creek Range and Highland and Bristol

Ranges then the following 8 D value for Lake Valley outflow is calculated:

(4) QmCm - Q 2c2 - Q 3C3 = cx Qi

9000(-107) - 4000(-102) - 2000(-103) = -116 permil

3000

where Q C = flow rate and S D of the mixture m m Q 1C 1 = flow rate and 5 D of recharge from Lake Valley subsurface outflow Q 2C2 = flow rate and 5 D of recharge from the Wilson Creek Range Q 3C3 = flow rate and 8 D of recharge from the Highland and Bristol Ranges

If current Lake Valley outflow is represented by a 5 D value of -

107 permil, as previously suggested, then a shift of 9 permil Is

required to explain the composition of Panaca Spring, given the

flow scenario in Table 5.

DISCUSSION

The geochemistries of dilute high altitude springs are

generally similar though to some extent controlled by lithology.

All high altitude springs are dominantly calcium bicarbonate type 66

water, though springs in carbonate areas contain higher magnesium and lower chloride concentrations than those in volcanic terrain.

Several thermal wells and springs are found in the study area.

Some of these may be preliminarily distinguished as local and regional discharge. Panaca Spring, site 42, is a sodium-calcium- bicarbonate water that discharges a large rate of flow,

approximately 8000 ac-ft/yr, from the valley floor. Mifflin

(1968) classifies the spring as regional based on a low tritium

content and concentrations of Na + K and Cl + S04 greater than 1

epm respectively.

In contrast, Bennett Spring, site 44, is of a lower

temperature, 24 deg C, discharges at a much lower rate, 10 gpm,

and is a calcium-magnesium-bicarbonate type water. The spring

discharges along a fault contact on the upper fan of the Highland

Range. Chemistry of the spring is identical to a spring located at

a higher altitude in the Highland Range. Bennett Spring most

likely represents local recharge in the Highland Range that has

circulated to depth before encountering a fault contact and

discharging. In a similar manner, sites 3 and 4 in Lake Valley

discharge warm water, 18 to 21 deg C, along the toe of an alluvial

fan, again probably a fault contact. Chemistry is similar to high

altitude springs in the Highland Range and Bennett spring. Mifflin

(1968) classifies the springs as local based on low Na + K and Cl +

S04 concentrations.

Within Panaca Valley, delineation of chemical processes has

focused on distinction of evaporative concentration from mixing and 67

dissolution. The importance of this distinction lies in identification of the magnitude of regional discharge and possible interaction with local flow. Major ion chemical data suggests evaporative concentration. However analysis of stable isotope data reveals no evaporation trends. Further evidence to dismiss evaporation is derived from a plot of chloride versus S D, which allows distinction of separate mixing and dissolution trends that apparently explain the data. Influence of Panaca Spring appears to be confined to sites adjacent to and immediately downgradient of the spring.

Both chloride and 5 D data suggest that outflow from Spring

Valley contributes largely to a local flow system. The source of regional discharge at Panaca Spring appears to lie to the north in

Lake Valley and Patterson Wash. Three flow scenarios were proposed for the regional system: 1) a well mixed, single layer system; 2) a two layer system with upward vertical flow; and 3) a two layer system with a downward vertical gradient.

A single layer system yields an 8 mg/1 difference between predicted and observed chloride concentrations at site 23 in

Patterson Wash, and does not describe the fate of cumulative flow in the wash though exit via carbonate rocks is implied. Deuterium balance calculations, assuming a single layer system in Patterson

Wash, result in predicted S D values 3 to 8 permil heavier than observed at Panaca Spring (-107 permil). A paleoclimatic shift of

9 permil in Lake Valley outflow may account for the difference. 68

Assuming a two layer system with upward vertical leakage results in a match of predicted and observed chloride

concentrations in Patterson Wash basin fill wells. However, this

scenario calculates a relatively large basin fill flow rate (9100

ac-ft/yr) that must be channelled through fractured volcanic rocks

at the terminus of Patterson Wash. In addition, the resultant

regional flow rate of 4700 ac-ft/yr is much less than observed at

Panaca Spring (8000 ac-ft/yr).

Finally, assuming a two layer system with downward leakage

yields predicted chloride concentrations lower than observed in

basin fill wells, though the difference may be accounted for by

dissolution of chloride minerals. A cumulative basin fill flow

rate of 4710 ac-ft/yr is estimated to exit the wash at the

terminus. Including a leakage rate of 2100 ac-ft/yr from overlying

basin fill, cumulative regional flow is estimated at 9100 ac-ft/yr.

The predicted chloride and S D values of this flow are 14 mg/1 and

-107 to -108 permil respectively, closely approximating observed

values at Panaca Spring of 16 mg/1 and -107 permil. This scenario

accounts for discharge of 8000 ac-ft/yr at Panaca Spring and

provides deep circulating water to account for the thermal nature

of the spring. 69

CONCLUSIONS

Objectives of the study were to develop a refined conceptual model of the flow system and identify interaquifer and interbasin flow relationships. Results of this study yield a conceptual understanding of the flow system similar to descriptions by Rush

(1964) and indicating a similar mixture of regional and local flow systems as suggested by Mifflin (1968). Specifically, the following conclusions are drawn:

1. Chloride and deuterium balance calculations suggest that

local flow is largely derived from volcanic terrain adjacent to

Spring Valley.

2. Regional discharge appears primarily confined to Panaca

Spring. Isotopically light thermal water near Caliente may

represent additional regional flow, although the magnitude of this

flow is not known since no surface discharge occurs.

3. Chloride and 5 D data indicate a fairly limited interaction

of regional discharge at Panaca Spring with local flow, apparently

confined to the immediate vicinity of Panaca Spring. This data

along with S ^ 0 data was also used to discount evaporation as a

significant process controlling chemistry in Panaca Valley and

instead suggest mixing and dissolution as primary controls. 70 eno 4

4. Using chloride concentration and 5 D as tracers to weight recharge estimates, three scenarios were constructed to describe groundwater flow from Lake Valley to Panaca Valley.

a. Assuming a single layer, well mixed flow system results

in a reasonable match of predicted and observed chloride

concentrations in basin fill wells of Patterson Wash. An

exception is site 23, in upper Patterson Wash, where an 8

mg/1 or 33 percent difference is calculated. This flow

scenario requires that virtually all of the cumulative

flow in Patterson Wash discharge at Panaca Spring.

Predicted S D values of this flow are 3 to 8 permil

heavier than observed at Panaca Spring (-107 permil).

This difference could be accounted for by a paleoclimatic

shift of 9 permil in subsurface outflow from Lake Valley.

b. A two layer, local and regional flow system with an

upward vertical gradient in upper Patterson Wash accounts

for dilution of chloride concentration in basin fill flow

of Patterson Wash. However, a disproportionately large

flow rate in basin fill (9110 ac-ft/yr) compared to

underlying carbonates (4710 ac-ft/yr) is estimated by this

scenario. Since it appears this basin fill flow must exit

Patterson Wash via fractured volcanic rocks, the estimated

flow rate may be unreasonably high. In addition, the

estimated regional flow rate of 4710 ac-ft/yr, though 71

matching the 5 D value, accounts for only 60 percent of

the discharge at Panaca Spring.

c. Assuming a two layer system with a downward vertical

gradient in upper Patterson Wash results in predicted

chloride concentrations lower than observed in basin fill

wells. Dissolution of chloride minerals would be required

to account for the difference. A match of predicted

regional flow rate, chloride concentration, and S D value

with that observed at Panaca Spring is achieved by this

flow configuration. Though not definitive given the level

of uncertainty in the analytical technique, this scenario

is preferred by the author.

5. None of the flow scenarios outlined result in large excesses of regional flow downgradient of Panaca Spring. Thus a significant interbasin transfer is not likely. The study area may comprise a single regional flow compartment, with volcanics and intrusives

associated with the Caliente caldera providing the southern boundary. 72

RECOMMENDATIONS

In a reconnaissance study as this, a fundamental purpose is to

identify critical locations requiring supplemental data. The value of additional spatial data in delineating groundwater flow in the upper Meadow Valley Wash area is questionable, particularly if flow

in the carbonate rock aquifer is of interest. Again, the

difficulty lies in limited availability of sites that tap the

carbonate system. The only area where additional stable isotope

data may be of use is in Patterson Wash. Samples from these basin

fill wells may not depict conditions in the carbonate system but would allow direct comparison of deuterium and chloride balance

calculations.

Another approach to more fully addressing some of the problems

posed by this study is to focus on individual components of the

system. Discharge may be quantified more accurately by monitoring

spring flow and water levels in Panaca Valley. Aquifer interaction

in the valley may be defined by determining a vertical gradient,

using nested piezometers, and collecting stable isotope and

chemical samples from discrete depths and along transects across

the wash. A shallow aquifer end member could then be identified

allowing more detailed mixing calculations.

Recharge may be characterized in a cursory manner by collecting

seasonal samples from high altitude springs. This data would yield 73

a seasonal range of isotopic compositions that may be interpreted and input into the model. A more desirable approach would be a comprehensive analysis of selected watersheds. By collecting precipitation and flow measurements, and stable isotope samples from lysimeters, piezometers and springs it may be possible to more accurately quantify and isotopically label recharge. In addition, the effect of lithology may be investigated by choosing and comparing data from carbonate and non-carbonate watersheds. REFERENCES

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Plummer, L.N., Jones, B.F., and Truesdell, A.H., 1976. WATEQF- A FORTRAN IV version of WATEQ, A computer program for calculating chemical equilibrium of natural waters. U.S. Geological Survey, Water Resour. Investig. 76-13.

Rowley, P.D., Lipman, P.W., Mehnart, H.H., Lindsey, D.A., and Anderson, J.J., 1978, Blue Ribbon Lineament, An East-Trending Structural Zone Within the Pioche Mineral Belt of Southwestern Utah and Eastern Nevada, USGS J. Research, v. 6, no. 2, p. 175- 192.

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Winograd, I.J., Szabo, B.J., Coplen, T.B., Riggs, A.C., and Kolesar, P.T., 1985. Two million year record of deuterium depletion in Great Basin Ground Waters. Science, v. 227, pp 519- 522. Winograd, I.J., and Thordarson, W . , 1975. Hydrogeologic and hydrochemical framework, south-central Great Basin, Nevada- California, with special reference to the Nevada Test Site. U.S Geol. Surv. Prof. Paper 712-C. Appendix 1. Summary of well data/ U.S. Geological Survey unpublished data.

0 RIM A ft Y ALTITUDE TOP OF HE PTH USE OF LAND OPEN WATER- WATER OF WELL OF SURFACE INTERVAL LEVEL LEVEL • LOCAL tJ U M 9 F R (FEET) SITE (FEET) (FEET)i DATE (FE

1 83 N05 E 6 5 0260 A 1 5 60 W 5960.00 200.00 03/12/1985 119.99 183 NO 6 E 6 o 30CBC 1 224 W 6067.00 182.00 03/15/1985 206.50 1 83 NO 6 E 6 7 56CCC 1 210 U 6522.00 03/13/1935 22.35

1 98 N01 E 69 31 CAC 1 110 W 5262.00 03/12/1985 90.00 198 N01 c 6 9 32BCC 1 -- W 5231.00 — 03/12/1985 53.44

198 N01 E69 32CAA 1 w 5185.00 03/12/1995 26.38

1 98 S01 E 6 9 060 AC 1 96.0 w 5155.00 16.00 03/12/1955 6.34

1 98 S01 E 69 06DBD 1 96.0 w 5155.00 28.00 03/12/1955 4 . 30

1 98 S01 E69 07CD 1 79.0 u 5115.00 30.00 03/12/1955 0.1 5

1 93 S01 E 6 9 32CDB 1 w 5184.00 — 03/12/1985 18.95

800 N01 E69 0 2 A (3 A 1 20.0 w 5700.00 -- 03/11/1985 41.78

200 - N01 E 69 1 OAOO 1 1 04 u 5492.00 12.00 03/11/1985 4. 49 2 200 N01 E 69 1 0 ADO 107 w 5482.00 36.00 03/11/1935 5.80

200 N01 E 69 10D0BC1 1 1 9 u 5471.00 2 0.00 03/11/1985 10.90

200 NO 2 E 6 9 3 5 A C D 1 3 6 . 0 w 5599.00 50.00 03/11/1955 15.64 PRIMARY ALTITUDE TOP OF 0 ■: P T H USE Oc LAND OPEN WATER- WATER OF WELL OF SURFACE INTERVAL LEVEL LEVEL FEET SITE FEET FEET DATE FEET

200 NO 2 E 69 3 5 DC A 1 79.0 W 5 393.00 03/11/1935 47.14 201 NO 2 E 6 9 2 4 B EC 1 127 k 5900.00 63.00 03/13/1985 50.30 201 NO 2 E 70 0700 1 W 5370.00 — 03/13/1985 11.81 201 NO 2 E70 036BC 1 3.0 U 5365.00 — 03/13/1935 3.10 201 NO 2 E 70 18CB4 1 17.0 U 5950.00 -- 03/13/1935 14.99 201 NO 3 £70 05 OBA 1 110 U 6103.00 -- 03/14/1935 72.01 201 N03 E 70 07 AC A 1 9.0 U 5999.00 03/14/1985 2.42 201 N03 E70 07 DA A 1 8.0 W 5995.00 -- 03/14/1985 4.69 201 NO 3 E 70 17BE&A1 74.0 W 5992.00 03/14/1985 17.61 201 NO 3 E 7 0 2 0 A 0 A 1 77.0 u 5974.00 03/13/1985 47.36 201 NO 3 E 70 32606 1 7.0 u 5900.00 — 03/13/1985 0.94 201 NO 4 E69 1 3 C 8 A 1 -- w 6253.00 03/14/1935 2.26 201 N04 E70 066Ba 1 -- u 6133.00 — 03/14/1985 5.55 202 N01 E67 080A 3 1 1 9 3 u 5920.00 -- 03/14/1935 202 N01 E67 12DAC 1 595 w 5480.00 264.00 03/15/1985 91 .as 20? N02 E66 25 0 A 8 1 400 u 5920.00 03/15/1985 354.49 202 NO 2 E 6 7 1 6 C A A 1 21.0 w 5574.00 03/14/1935 20.17 202 NO 2 E 6 7 16CCB 1 450 w 5590.00 50.00 03/15/1985 40.39 202 N02 E 67 22000 1 100 u 5533.00 25.00 03/13/19S5 22 . 71 202 NO 2 £67 35 BCD 1 139 0 5520.00 03/14/1935 55.43 202 NO 2 E63 27 A 0 B 1 30.0 u 5940.00 15.00 03/15/1985 14.35 202 MO 3 566 08 0 A B 1 303 w 5863.00 223.00 03/12/1935 216.07 202 NO 3 E 6 6 11 ABB 1 140 w 5747.00 -- 03/17/1985 91 . 32

■^J VO i044 Reno PRIMARY ALTITUDE TOP OF DEPTH USE OF LAND OPEN WATER- WATER OF WELL OF SURFACE INTERVAL • LEVEL LEVEL LOCAL NUMBER (FEET) SITE (FEET) (FEET) DATE (FE

— 202 NO 3 £66 1 5C6C 1 131 U 5773.00 03/16/1985 116.42 202 N03 £66 23DAC 1 45.0 U 5674.00 -- 03/14/1985 202 N03 E 6 6 2 3DAC 2 1 46 W 5674.00 -- 03/14/1985 40.29 202 N03 E 6 7 0 5 AC 0 1 382 w 5974.00 03/13/1985 324.06 202 NO 3 E 6 7 23BCC 1 395 w 5950.00 03/14/1985 366.30 202 N04 E 6 6 1 4 0 B A 1 20 6 w 5668.00 230.00 03/12/1985 170.05 202 N05 £6 6 3 5 DC C 1 296 w 5934.00 200.00 03/12/1985 195.36 202 NO 5 E 67 3 5 BC b 1 25.0 w 6780.00 3.00 03/16/1985 1 .81 203 S01 E63 333 1 1 20 w 4850.00 60.00 03/26/1966 37.79 203 S02 E63 0 3 3 5 110 0 4720.00 03/26/1986 1 7.06 203 S 03 E 6 7 02 A 1 22 5 w 4605.00 — 03/26/1936 24.73 204 S03 E 71 31CBBA1 262 w 5948.00 03/12/1935 207.74 204 S04 E69 27CDCB1 250 w 5633.00 03/14/1935 227.17 204 SO 4 E70 11CC0D1 1 97 w 5789.00 175.00 03/14/1935 166.84 204 S 04 E70 33CAB 1 499 w 5546.00 3 7.00 03/14/1935 6.24 204 SOS £69 15ADDD1 40.0 w 5349.00 22.00 03/14/1935 11.34 204 SOS E 70 31ACBD1 199 w 5555.00 150.00 03/14/1985 112.40

oo o 1044 Reno Appendix 2. Location ana physical characteristics of samples collected in the Meadow Valley Wash Area.

Map No. Name Twp Rng Section Date Temp pH EC Source

Lake Valley

1 North Creek Sp 1 ON 64 E 04/03/85 8.5 6.9 75 1 2 Geyser Sp. 1 ON 6 5 E 34 04/03/85 12.0 7.8 220 1 3 North Big Sp 9N 6 5 E 1 2 BD 04/04/55 20.5 7.6 385 1 4 South Big Sp 9N 6 5 E 1 2 CA 04/04/35 18.5 7.5 360 1 5 Lake V. Irr. Well 6N 66 E 29 ABC 06/07/85 18.0 8.1 488 1 6 Lower Pony Sp 5N 6 6 E 5 CC6 04/05/85 14.0 7.9 360 1 7 Steward Ranch Sp 5 N 6 5 E 11 AD 04/05/85 8.0 7.0 304 1 8 Upper Pony Sp 5N 6 5 E 1 BC 04/05/85 9.0 8.3 424 1 9 Wilson Cr 5 N 63E 6 C 04/05/85 17.0 3.0 198 1

Spring Valley

10 Burnt Canyon Sp 5 N 69 E 14 DDAO 06/05/85 11.0 7.6 250 1 1 1 Camp Creek 5 N 69 E 33 D 04/09/35 9.0 7.9 180 1 1 2 Parsnip Sp 3 N 69 E 4 BCC 06/05/85 19.0 7.7 154 1 1 3 Spr below Reed Summit 3N 71 E 18 A 04/09/85 8.0 7.9 651 1 14 White Rock Well 3N 7 0 E 8 CC 07/24/75 14.5 7.9 5 25. 2 1 5 Little White Rock Sp AN 6 8 E 1 AB 07/24/75 15.0 8.0 310 2 1 6 MVW above Eagle Canyon 2N 70 E 1 8 C 04/09/35 19.0 8.2 803 1

Patterson Wa s h

17 Pine Sp 1 N 6 6 E 35 BB 04/07/85 4.5 1 .1 8 Lime Sp 1 N 6 6 E 26 DA 04/07/85 21.0 8.3 500 1 1 9 Highland Sp 1 N 6 6 5 26 BA 04/07/85 10.0 7.2 636 1 20 Deadman Sp 1 N 66E 26 AD 04/07/85 9.5 7.1 719 1 21 Dodge Well 5 N 6 6 E 35 DC 07/25/75 18.0 8.1 485 2 OO )044 ■ Rene Map No. Name T wp Rng Section Date Temp pH EC Source

22 Wildhorse Sp AN 6 6 E 20 B 3 0A/05/85 .8.0 7.6 5 AO 1 23 Patterson Wash Well 3N 66E 2 D 07/25/75 18.0 3.1 35 5 . 2 2 A Eight Mile Well 2N 6 7 E 16 0 07/25/75 19.0 6.5 3A5 2 25 Well near Pioche 1 N 6 7 E 1 2 D 07/25/75 24.0 7.3 280 2 - - 26 Pioche Well #1 1 N 6 7 E 1 A 05/15/73 8.0 2 27 Pioche Well d3 1 N 67E 1 A 05/15/73 7.9 — 2 * Panaca and Dry Valleys

- - 28 MVW above Delmues 1 S 6 3 E 1 3 DB 0A/03/85 18.0 1 29 Spring V Wash 1 N 6 9 E 1 5 CC 07/2A/75 21.5 8.1 875 . 2 30 Echo Dam Well 1 N 69 E 32 12/02/69 - - 7.3 - 2 31 Deer Lodge Canyon Sp 1 N 70 E 26 AD 07/24/75 19.0 8.1 565 2 - 32 Conserv. Camp Well 1 S 6 8 E 1 3 A 10/ /A6 15.0 - 2 33 Oxborrow Well 1 S 6 9 E 6 DB 06/05/85 11.5 7.9 1080 1 - 3 A Well near Panaca 2 S 6 8 E 5 05/15/73 - 7.9 2 - 35 USGS Observ Well 2 S 6 8 E 8 B 12/03/63 - 3390 2 36 Lester Mathews Well 2S 6 3 E 8 BAD 06/0A/35 20.0 8.1 1 oso 1 37 J. Wadsworth Well 2 S 63 E 1 3 DD 06/04/35 14.5 7.5 1510 1 38 Weaver Well 2S 67 E 25 DA3B 06/04/35 17.0 7.7 1 280 1 39 North Lee Well 1 S 68 E 32 3 B A A 06/04/85 22.0 3.0 576 1 AO Panaca Town Well 2 S 6 3 E 5 CDD 06/04/85 29.5 7.9 537 1 A1 Delmues Sp 1 S 6 3 E 1 3 DB 04/03/85 18.0 7.7 426 1 A 2 Panaca Sp 2 S 68c A BAD 04/03/85 29.5 7.9 416 1 A3 Flatnose Sp 1 N 695 35 CC 04/08/85 25.0 3.0 335 1 AA Bennett Sp 2 S 67 E 7 CD 04/10/85 24.0 7.5 49 A 1 A 5 Caliente Hot Spring AS 6 7 E 8 B 04/10/85 45.0 7.8 434 1 A6 Wallis Well AS 67 E 8 12/ /7 9 67.0 7.7 41 A. 3 A7 Hospital Reinject W AS 67 E 8 12/ / 7 9 29.2 7.5 617. 3 A 8 Hospital Old Well A S 6 7 E 3 12/ /7 9 48.6 7.8 476. 3 A 9 L Van Kirk Well AS 675 8 12/ /7 9 42.8 8.1 462 . 3 50 K. Phillips Well AS 6 7 E 8 12/ /79 42.0 7.8 432. 3 51 Cox Well 35 675 2 06/11/72 - 7.9 - 2

r\ Map No. Name Ttup Rng Section Date Temp pH EC Source

- 52 Highland Knoll Well 3 S 67 E 2 0 B 9 05/04/73 - 7.8 53 Well near Caliente 3 S 67E 22 06/20/72 - 3.2 - 54 Well near Caliente 3 S 67 E 28 AC 06/18/72 - 8.0 - 55 Oak Wells 3 S 6 9 E 35 DC 07/22/75 19.0 7.2 505

Clover Valley

56 Dutch Flat Well 4 S 67E 23 B 07/22/75 24.5 7.1 265 57 LOS Well 4 S 67E 8 12/ /79 24.0 7.6 81 3 58 Miller Well 4 S 67 E 8 12/ /79 39.7 7.8 554 59 Caliente City Well 45 67 6 8 12/ /7 9 15.0 7.8 398 60 Clover V Wash 4 S 67 E 8 12/ /79 12.0 7.7 7 53 61 Meadow V Wash/ Cal. 4 S 6 7 E 5 12/ /7 9 5.0 7.3 990 62 N. Ella Sp 5 S 67 = 06/03/85 10.0 240 63 Clover Creek V Well 4 S 69 E 27 cc 07/18/75 26.0 7.8 315 64 Clover Creek V Well 5 S 69 E 1 6 BD 07/18/75 21.5 7.8 415 - - 65 UP Well at Carp 10S 67 E 3 05/26/73 8.1 rvir\jr\j-*uuuw^r\j rorororo 66 Ramone Mathews Well 5 S 695 11 CAA 06/03/85 18.5 -7.8 352 67 Acoma Well 5 S 70E 4 BA 06/03/35 17.0 7.7 336 63 Sheep Sp 6 S 69 E 06/03/85 10.0 6.3 19 4

Source : 1 Sample collected by personnel of the U.S. Geological Survey. 2 From Bateman (197o). 3 From Trexler (1980). Appendix 3. Analyses of major constituents in mg/1/ Meadow Valley Wash Area

Map No . Name HC03 Cl S04 F Na ■ K C a Mg S iC 2 TDS

Lake Valley

1 North Creek Sp 2 Geyser Sp 3 North Big Sp 240.0 6.0 12.0 0.2 5.3 2.1 49. 19.0 21 . 355 4 South Big Sp 200.0 5.6 12.0 0.2 5.4 1.9 45. .18.0 13. 306 5 Lake V. Irr. Well 121 .0 68.0 25.0 .0.2 22.0 2.1 61 . 9.7 25. 334 6 Lower Pony Sp 202.0 10.0 8.2 0.1 36.0 1.1 45. 2.0 47. 351 7 Steward Ranch Sp 161.0 7.9 12.0 0.2 17.0 0.6 38. 5.9 46. 239 8 Upper Pony Sp 256.0 11 .0 15.0 0.2 22.0 •1.4 60. 14.0 57. 437 9 Wilson Cr 77.0 7.0 11.0 0.3 11.0 2.9 21. 3.3 39. 172

Spring ’Valley

10 Burnt Canyon Sp 1 40.0 5.2 8.2 0.1 8.1 0.5 35. 7.7 33. 243 11 Camp Cr S 12 Parsnip Sp 70.3 7.5 9.1 0.1 12.0 2.2 16. 3.0 41 . 1 61 1 3 Spr below Reed Summit 372.0 23.0 25.0 0.3 26.0 2.4 92. 19. 23. 533 14 White Rock Well 168.0 51 .0 20.0 . 6 11.0 4.0 69. 10.0 61 . 394 1 5 Little White Rock Sp 1 51.0 12.0 10.0 - 13.0 5.0 37. 8.0 - 235 1 6 MVW above Eagle Canyon — — — — — — ””

Patterson Wash 4

------17 Pine Sp - - 18 Lime Sp 289.0 4.1 8.9 0.1 3.8 0.9 55. 31 .0 14. 407 19 Highland Sp 474.0 4.4 8.1 0.1 4.7 1.0 36. 36.0 15. 629 20 Deadman Sp 5 0o. 0 4.2 8.3 0.1 5.0 0.9 98. 41 .0 19. 632 21 Dodge Well 137.0 44.0 32.0 0 . 0 3.0 2.0 64. 11 .0 - 290 - 22 Wildhorse Sp - - - - - — - - 00 -O'

5 oust Map No. Name HC03 Cl S04 F Na K C a Mg Si02 TDS 8 23 Patterson Wash Well 1 22.0 24.0 17.0 .2 3.0 3.0 44 0 51 . 272 24 Eight Mile Well 148.0 21.0 13.0 - 10.0 5.0 28 15 0 240 Well near Pioche 114.0 21 .0 11.0 . 3 13.0 5.0 33 4 0 275 25 - 110.0 18.0 15.0 . 3 20.0 30 5 0 205 26 Pioche Well #1 - 27 Pioche Well #3 115.0 19.0 14.0 0.2 7.0 30 5 0 200

• ' Panaca and Ory Va

28 MVW above Delmues - - - 29 Spring V.Wash 396.0 70.0 46.0 1.0 72.0 11.0 87 17 0 53. 753 - 8 - 30 Echo Dam Well 298.0 43.0 25.0 .7 56.0 70 0 505 - 31 Deer Lodge Canyon Sp 2 76.0 19.0 44.0 - 5.0 • 4.0 80 1 3 0 440 - - 8 - Conserv. Camp Well 1 84.0 33.0 24.0 27.0 53 0 330 32 22 33 Oxborroui Well 351.0 140.0 63.0 0.8 65.0 11 .0 1 30 0 58. 841 - 1 2 193.0 17.0 31.0 1 . 7 43.0 32 0 - 330 34 Well near Panaca - 35 USGS Observ Well 1130.0 282.0 507.0 12.0 795.0 22 24 0 85. 2857 21 36 Lester Mathews Well 425.0 44.0 1 70.0 3.1 1 40.0 10.0 73 0 64. 951 37 J. Wadsworth Well t>01 .0 83.0 200.0 6.5 150.0 9.5 1 20 47 0 76. 1298 38 Weaver Well 4 23.0 110.0 1 80.0 2.9 110.0 14.0 100 42 0 73. 1060 1 2 39 North Lee Well 21 S.O 48.0 33.0 1.0 44.0 9.9 59 0 54 . 479 Panaca Town Well 203.0 19.0 68.0 1.8 47.0 3.3 45 13 0 58. 463 40 6 41 Delmues Sp 132.0 24.0 18.0 0.6 30.0 6.3 47 7 6 4. 379 42 Panaca Sp 194.0 16.0 25.0 1 . 5 38.0 7.1 34 10 0 50. 376 43 Flatnose Sp 146.0 10.0 18.0 1.3 34.0 5.6 26 3 5 55 . 299 7.9 6.9 0.0 6.5 1.5 56 26 0 14. 3 80 44 Bennett Sp 261.0 “T 45 Caliente Hot Spring 2 22.0 13.0 34.0 1.4 49.0 19.0 37 7 1 30. 513 46 Wallis Well 191.0 7.8 33.2 1.6 39.5 15.4 33 4 7 103 . 429 6 Hospital Reinject W 3 23.0 9.3 31 .7 2.5 69.7 35.5 40 4 151 . 669 47 6 48 Hospital Old Well 1 S6.0 15.3 37.2 1.4 45.7 17.1 38 6 103. 450 6 49 L Van Kirk Well 231.0 13.4 19.1 1.7 54.1 23.0 25 4 114. 438 50 K. Phillips Well 209.0 17.3 30.8 1.4 49.5 18.4 30 3 0 113. 477 - 20 - 51 Cox Well 2 88.0 48.0 74.0 2.0 76.0 53 0 560 - - 52 Highland Knoll Well 569.0 241.0 197.0 1.7 260.0 61 59 0 1390 ouei M 3P No. Name HC03 Cl S04 Na K Ca Mg Si02 TO S

- - 52 Well near C aliente 320.0 59.0 42.0 . 7 65.0 eo. 13.0 585 - - 54 Well near C a lien te 459.0 34.0 70.0 .6 85.0 125. 18.0 850 55 Oak Wells 1 39.0 29.0 18.0 2.0 5.0 70. 13.0 325

Clover Valley

56 Dutch Flat Well 1 58.0 9.0 11.0 15.0 3.0 35. 3.0 240 57 LDS Well 337.0 23.2 53.7 1 . 4 63.7 20.2 53. 16.1 95. 663 53 Millar Well 254.0 19.5 43.6 1 . 4 46.9 16.4 46. 8.2 113. 549 59 Caliente City Well 232.0 12.5 5.6 1.7 27.6 4.6 53. 6.6 47. 391 60 Clover V Wash 371 .0 19.0 18.7 1.6 43.3 6.4 77. 13.9 54. 610 61 Meadow V Wash/ Cal. ' 3 87.0 59.1 66.2 2.0 94.6 15.4 58. 25.0 59. 766

62 N Ella S p - Clover Creek V Well 166.0 17.0 4.0 10.0 5.0 41 . 6.0 250 63 - 64 Clover Creek V Well 1 30.0 26.0 13.0 .4 8.0 3.0 60. 6.0 360 65 UP Well at Carp 349.0 67.0 72.0 1.4 90.0 10.0 71 . 24.0 - 690 66 Ramone Mathews Well ' 171 .0 15.0 12.0 0.3 20.0 5.9 42. 6.3 61 . 334 67 Acoma Well 149.0 17.0 10. 0.3 21.0 7.0 33. 5.3 54. 302 63 Sheep Sp 95.0 7.9 7.0 0.7 9.8 1.3 24, 5.0 33. 1 35

0 0 O'

s ouefc Appendix 4. Log IAP/KT with respect to calcite and dolomite, calculated by WATEQF (Plummer et al., 1976).

Name Calcite Dolomite

Lake Valley

1 North Creek Sp 2 Geyser Sp 3 North Big Sp 0.159 0.200 4 South Big Sp -0.074 -0.282 5 Lake V. Irr. Well 0.408 0.277 6 Lower Pony Sp 0.269 -0.620 7 Steward Ranch Sp -0.876 -2.477 8 Upper Pony Sp 0.781 1.036 9 Wilson Cr -0.287 -1.136

Spring Valley

10 Burnt Canyon Sp -0.318 -1.154 11 Camp Cr 12 Parsnip Sp -0.701 -1.858 13 Spr below Reed Summit 14 White Rock Well 0.349 0.068 15 Little White Rock Sp 16 MVW above Eagle Canyon

Patterson Wash

17 Pine Sp 18 Lime Sp 0.947 1.951 19 Highland Sp 0.089 -0.080 20 Deadman Sp 0.055 -0.157 21 Dodge Well 0.481 0.457 22 Wildhorse Sp 23 Patterson Wash Well 0.301 0.120 24 Eight Mile Well -1.381 -2.762 25 Well near Pioche -0.536 -1.651 26 Pioche Well #1 27 Pioche Well #3

Panaca and Dry Valley

28 MVU above Delmues 29 Spring V Wash 30 Echo Dam Well 31 Deer Lodge Canyon Sp 32 Conserv. Camp Well 33 Oxborrow Well 0.811 -1.352 Name Calcite Dolomite

34 Well near Panaca 35 USGS Observ Well 36 Lester Mathews Well 0.928 1.614 37 J. Wadsworth Well 0.587 0.979 38 Weaver Well 0.620 1.116 39 North Lee Well 0.584 0.793 40 Panaca Town Well 0.433 0.729 41 Delmues Sp 0.093 -0.402 42 Panaca Sp 0.330 0.530 43 Flatnose Sp 0.158 -0.203 44 Bennett Sp 0.191 0.388 45 Caliente Hot Spring 46 Wallis Well 47 Hospital Reinject W 48 Hospital Old Well 49 L Van Kirk Well 50 K. Phillips Well 51 Cox Well 52 Highland Knoll Well 53 Well near Caliente 54 Well near Caliente 55 Oak Wells 56 Dutch Flat Well 57 LDS Well 0.335 0.495 58 Miller Well 0.576 0.887

Lower Meadow Valley Wash

59 Caliente City Well 0.303 -0.089 60 Clover V Wash 0.476 0.367 61 Meadow V Wash, Cal. 0.328 0.319 62 N Ella Sp 63 Clover Creek V Well 65 UP Well at Carp 66 Ramone Mathews Well 67 Acoma Well 68 Sheep Sp Appendix 5. Stable isotope data for the Meadow Valley Wash Area

1 8

Name 5 0 6 D

Lake Valley

North Creek Sp -14.6 -105.0 Geyser Sp -14.5 -105.0 North Big Sp -15.1 -112.0 South Big Sp -14.8 -111.0 Lake V. Irr. Well -14.7 -111.0 Lower Pony Sp -13.3 -101.0 Steward Ranch Sp -13.6 -102.0 Upper Pony Sp -13.2 -99.5 Wilson Cr -13.2 -97.5

Spring Valley■

Burnt Canyon Sp -12.3 -93.0 Camp Cr -14.0 -102.0 Parsnip Sp -12.8 -93.5 Spr below Reed Summit -12.5 -95.0 Spring V Wash - Echo Dam Well - Deer Lodge Canyon Sp - White Rock Well -13.1 -101.0 Little White Rock Sp - MVW abv Eagle Canyon -12.0 -93.0

Patterson Wash

Pine Sp -13.4 -99.0 Lime Sp -12.9 -97.0 Highland Sp -13.3 -98.5 Deadman Sp -13.3 -99.0 Dodge Well -14.2 -107.0 Wildhorse Sp -11.7 -92.5 Patterson Wash Well - Eight Mile Well - Well near Pioche - Pioche Well #1 -

Panaca and Dry Valleys

MVW at Delmues -12.8 -98.0 Oxborrow Well -11.8 -92.0 Lester Mathews Well -13.3 -103.0 J. Wadsworth Well -12.9 -101.0 Weaver Well -13.1 -101.0 90 Rene )44

1 8

Name S 0 S D

North Lee Well -13.3 -101.0 Panaca Town Well -14.0 -106.0 Delmues Sp -13.4 -104.0 Panaca Sp It -14.0 -108.0 -13.9 -106.0 Flatnose Sp -13.4 -101.0 Bennett Sp -13.7 -103.0 Caliente Hot Spring It -14.5 -109.0 -14.3 -106.0 * Wallis Well -14.6 -109.0 * Hospital Reinject W -14.4 -109.0 * L Van Kirk Well -14.4 -109.0 *

Clover Mountains

CalienteIt City Well -12.1 -84.0 * -12.4 -89.0 Clover V Wash -11.7 -84.0 Meadow V Wash, Cal. -13.1 -97.0 N. Ella Sp -11.6 -86.5 Ramone Mathews Well -12.3 -92.0 Acoma Well -12.6 -95.0 Sheep Sp -12.0 -87.0 Lower Meadow Valley Wash Randono Well -11.7 -87.5 Railroad Well -11.6 -86.0 Jensen Well -11.6 -88.5 Farrier Well -12.5 -97.5 Big Muddy Sp -12.9 -96.5 Bradshaw Well -11.7 -88.5 Morman Mountains Bishop Sp -11.7 -85.5 Davies Sp -12.5 -89.0 Hackberry Sp -12.3 -87.0 Kane Springs Wash Boulder Sp -12.6 -87.0 Grapevine Sp -12.0 -87.5 Kane Sp -11.9 -86.5

* Data from Trexler et al. (1980).