T E X A S

WATE R

oEVEl 0 PMEN T

BOA R0

REP 0 RT 78

GROUND-WATER RESOURCES OFUPTON COUNTY, TEXAS

MAY 1968

TEXAS WATER DEVELOPMENT BOARD

REPORT 78

GROUND-WATER RESOURCES OF UPTON COUNTY, TEXAS

By

D. E. WhiteUnited States Geological Survey

Prepared by the U.S. Geological Surveyin cooperation with the

Texas Water Development Boardand the

Commissioners Court of Upton County

May 1968

Mills Cox, ChairmanRobert B. GilmoreMilton T. Potts

TEXAS WATER DEVELOPMENT BOARD

Marvin Shurbet, Vice ChairmanGroner A. PittsW. E. Tinsley

Howard B. Boswell, Executive Director

Authorization for use or reproduction of any material contained in this publication,I~e., not obtained from other sources, is freely granted without the necessity of securingpermission therefor. The Board would appreciate acknowledgement of the source oforiginal material so utilized.

Published and distributedby the

Texas Water Development BoardPost Office Box 12386.A,ustin, Texas 78711

ii

TABLE OF CONTENTS

Page

ABSTRACT ...................................................•......................

INTRODUCTION ..................................................•.................. 3

Purpose and Scope of Investigation , , , , . . . . . . . 3

Methods of Investigation .. , , , , .. , , . , , .. , , , . . . 3

Location and Extent of Area ." "" " " .. "....... 4

Previous Investigations " " " " " " ". 4

Economic Development .. "" "" " "" " " "....... 4

Topography and Drainage. , ' , . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Climate" , , , , " , . . . . . . 6

Well-Numbering System " " " " "" " .. " .. ". 6

Acknowledgments .. , , , , , , .. , , . . 6

GEOLOGY AS RELATED TO THE OCCURRENCE OF GROUND WATER. . . . .. ... .. .•. .. . . . .. . .. 6

General Stratigraphy and Structure .. , , , .. , .. , , 6

Physical Characteristics and Water-Bearing Propertiesof the Geologic Units " " .. " " " 12

Triassic System .. "" " " "................. 12

Dockum Group " " ". 12

Tecovas Formation , , , . . . . . . . . . . . 12

Santa Rosa Sandstone , . . . . . . . . 12

Chinle Formation Equivalent " " " .. " .. " .. " "" .. ".. 14

Cretaceous System , , .. , , , , , . . . . . . . . 14

Trinity Sand , , . , .. , , .. , , . , , . 14

Fredericksburg Group "."" " " "." .. "." "" .. " .. """ 19

Washita Group .", , . , , , , , .. , , . 19

Quaternary System " " "" .. "..... 19

Pleistocene and Recent Series" , .. , . . . . . . . . . 19

iii

TABLE OF CONTENTS (Cont'd.)

Alluvium and Eolian Deposits .

Aquifers

GROUND-WATER HYDROLOGY .

Source and Occurence of Ground Water .

Recharge, Movement, and Discharge .

Hydraulic Properties of the Aquifers .

Use of Ground "'later .

Public Supply .

City of Rankin .

City of McCamey .

Industrial Supply .

Waterflooding .

Gasol ine Plants and Compressor Stations .

Other Industrial Uses .

Irrigation " .

Domestic and Livestock " .

Fluctuations of VVater Levels .

Well Constructioll .

CHEMICAL QUALITY OF GROUND WATER .

Trinity Sand .

Santa Rosa Sandstone .

Other Aqu ifers .

GROUND-WATER PROBLEMS .

Contamination from Disposal of Oil-Field Brines .

Contamination from Improperly Cased Wells .

Declines of Water Levels and Well Yields .

AVAILABILITY OF GROUND WATER ..........•...................•....•................

CONC LUSI ONS .................................................•.......•...•.........

iv

Page

19

19

20

20

20

21

25

25

28

28

28

28

32

32

32

32

32

35

35

39

40

40

41

41

48

48

48

49

TABLE OF CONTENTS (Cont'd.)

Page

REFERENCES CI1'ED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

TABLES

1. Geologic Units and Their Water-Bearing Characteristics 10

2. Coefficients of Permeability and Transmissibility DeterminedFrom Pumping Tests of Selected Wells .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

3. Source and Significance of Dissolved-Mineral Constituentsand Properties of Water. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

4. Reported Brine Production and Disposal in 1961 42

5. Records of Wells and Test Holes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

6. Chemical Analys.es of Water from Wells. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

7. Chemical Analyses of Oil-Field Brine and IndustrialWaste Water. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

FIGURES

1. Map Showing the Location of Upton County. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2. Graph Showing Annual Precipitation at McCamey, 1933-65 7

3. Graph Showing Average Monthly Temperature and Precipitation atMcCamey and Gross Lake Evaporation in Upton County. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

4. Diagram Showing Well-Numbering System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

5. Map of Parts of West Texas and New Mexico Showing PermianStructural Features 13

6. Map Showing Approximate Altitude of the Top of the Trinity Sand. . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

7. Map Showing Approximate Altitude of the Base of the Trinity Sand , .. . .. .. . . .. 17

8. Map Showing Approximate Altitude of Water Levels in Wells 23

9. Graph Showing Relation of Drawdown to Distance from the Centerof Pumping with Different Discharges and Coefficients of Transmissibility. . . . . . . . . . . . . . . . . . . . . . 26

10. Graph Showing Relation of Drawdown 0 Distance from the Centerof Pumping and Time for an Aquifer Having the Characteristics of the Trinity Sand. . . . . . . . . . . . . . . 27

11. Graph Showing Ground-Water Use, 1951-65 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

12. Graph Showing Quantity, Quality, and Source of Ground Water Pumpedfor Waterflooding, 1955-65 : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

13. Hydrographs of Three Wells in the Trinity Sand 33

v

TABLE OF CONTENTS (Cont'd.)

Page

14. Hydrograph of WHII YL-44-49-301, Pumpage from Wells in the UptonCounty Well Field, and Precipitation at Rankin, May 1964-September 1966 . . . . . . . . . . . . . . . . . . . 34

15. Map Showing the Chemical Quality of the Ground Water from Wellsin Upton County and Adjacent Areas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

16. Map Showing Location of Brine Producing Areas in 1961,and the Chloride and Sulfate Contents of Water from Selected Wells. . . . . . . . . . . . . . . . . . . . . . . . . 45

17. Graph Showing Relation of Chloride and Sulfate Concentrations toDischarge of Wf~1I YL-44-26-513. . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

18. Map Showing Estimated Potential Yields of Wells Tapping the Trinity Sand and Alluvium. . . . . . . . . . . 51

19. Geologic Map Showing Well Locations 133

20. Generalized Geologic Section A-A'

21. Generalized Geologic Section B-B'

vi

135

137

GROUND-WATER RESOURCES OF UPTON COUNTY, TEXAS

ABSTRACT

Upton County, 1,312 square miles in area, is inwest Texas. The water needs of the county are suppliedentirely from ground water, the Trinity Sand being theprincipal source.

Water used n the county during 1965 was 6,781acre-feet, of which 2,887 acre-feet, or 42 percent, wassupplied by wells in adjacent counties. Of the 3,928acre-feet of water pumped from wells in Upton County,3,590 acre-feet, or 91 percent, was from the TrinitySand. By far the qreatest use of ground water pumpedfrom wells in the county is for irrigation.

Recharge to the Trinity Sand of Cretaceous age issmall. The amount being transmitted through the aquiferat the present hy'draulic gradient, which is roughlyequ ivalent to the annual recharge, is about 1 mgd(million gallons per day), or about 1,100 acre-feet peryear, considerably less than was pumped from theaquifer in 1965.

The water from the Trinity Sand is of the calciummagnesium sulfate type; few wells yield water containingless than 1,000 ppm (parts per million) dissolved solids.Rocks older than the Trinity Sand-principally the SantaRosa Sandstone of Triassic age and San Andres Lime­stone of Permian age-contain water too highly miner­alized for uses other than livestock watering and oil-fieldwaterflooding.

Because of the low rate of recharge, presentpumping from the Trinity Sand is, in effect, a miningoperation. Additional development of the aquifer isexpected, with the water being obtained from the 8million acre-feet of water estimated to be available towells in the Trinity Sand. The percentage of this waterthat can be developed is not known; it will depend onthe construction, spacing, and discharge rates of thewells. Because of the low transmissibility of the aquifer,many low-yield and adequately spaced wells will berequired for maximum development of the water instorage. Contamination of the water in the Trinity Sandby the disposal of oil-field brines in unlined surface pitsalso may reduce the amount of water that can bedeveloped for purposes other than waterflooding.

GROUND-WATER RESOURCES OF UPTON COUNTY, TEXAS

INTRODUCTION

Purpose and Scope of Investigation

The investigation of the ground-water resources ofUpton County began in September 1965 as a coopera­tive project of thH U.S. Geological Survey, the TexasWater Development Board, and the CommissionersCourt of Upton County. The purpose of the investi­gation was to determine and evaluate the ground-waterresources of the county. The results of the investigationare presented in this report, which includes an analyticaldiscussion of the occurrence and availability of groundwater and a tabulation of basic data obtained during theinvestigation.

The scope of the investigation encompassed thecollection, compilation, and analysis of data related toground water, including: determination of the locationand extent of the water-bearing formations, the chemicalquality of the water they contain, the quantity of waterbeing withdrawn, and the effects of these withdrawalson the water levels; the hydraulic characteristics of theprincipal water-bearing formation; and estimates of thequantities of ground water available for development.

Methods of Investigation

The followin'~ procedures were used in the investi­gation.

1. Public sllpply, irrigation, and industrial wells,and a representative number of domestic and livestockwells (a total of 622 wells) were inventoried. Records ofwells are included in Table 5; locations of wells areshown on Figure lB.

2. Electric, radioactivity, and drillers' logs ofwells were collectBd for correlation and evaluation ofsubsurface characteristics of the water-bearing units.

3. The quantities of water used for public supplyand industry were inventoried, and the quantities usedfor irrigation, domestic supply, and livestock wereestimated (F igure 11).

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4. The results of 21 pumping tests (Table 2) wereused to determine the hydraulic characteristics of thewater-bearing sands.

5. Water levels were measured and availablerecords of past fluctuations of water levels were com­piled (Figures 13 and 14; Table 5).

6. Climatological records were compiled (Figures2 and 3).

7. Water samples were collected from wells todetermine the chemical quality of water (Table 6 andFigure 15).

8. Chemical analyses of oil-field brines andindustrial waste water (Table 7) and reported 1961oil-field brine production and disposal data were com­piled (Table 4).

9. A map was drawn showing the 1965-66chloride and sulfate concentrations in water from theshallow aqu ifers and areas and amounts of 1961reported brine disposal (Figure 16).

10. Maps showing the altitude of the top and baseof the Trinity Sand (Figures 6 and 7) and two geologicsections (Figures 20 and 21) were constructed fromelectric, radioactivity, and drillers' logs.

11. A map showing the altitude of water levels inselected wells tapping the alluvium, FredericksburgGroup, Trinity Sand, Chinle Formation equivalent, andSanta Rosa Sandstone (Figure 8) was constructed fromwater-level measurements and altitudes of wells. (Thealtitudes had been obtained from topographic maps andaltimeter surveys.)

12. The hydrologic data were analyzed to deter­mine the quantity and quality of ground water availablefor development. A map showing areas most favorablefor future development was drawn (F igure 18).

Location and Extent of Area

Upton County i~ an area of 1,312 square miles inwest Texas (Figure 1). The county is bordered by: Ectorand Midland Counties on the north, Reagan County onthe east, Crockett County on the south, and CraneCounty on the west. f~ankin, the county seat, is in thesoutheastern part of the county, about 55 miles south ofMidland. Most of the county is sparsely populated ranchland. In 1960, the county had a population of 6,239, ofwhich McCamey had ~:,375 and Rankin, 1,214. Midkiff,a small oil and farmin!J center in the northeast corner ofthe county, had an estimated population of 75.

Previous Investigations

No detailed in\festigation of the ground-waterresources of Upton County had been made prior to th isstudy. A reconnaissance report by Brown and others(1965) provides a gen(~ralized evaluation of the ~Jround­

water conditions in the Rio Grande basin, whichincludes the southwestern three-fifths of Upton County.A similar report on a study of the ground-waterresources of the Colcrado River basin, by Mount andothers (1967), includ(~s the northeastern two-fifths ofthe county.

Rayner (1959) compiled records of water-levelmeasurements in obs(~rvation wells in Upton Countyfrom 1954 through 1H57. Currently, water levels in sixwells in the county eire being measured at annual orbimonthly intervals as part of the Texas Water Develop­ment Board's observation well program.

The water supplies of Rankin and McCamey weredescribed by Broadhurst, Sundstrom, and Weaver (1951,p. 157-158) in their inventory of the public watersupplies of 81 counties in west Texas.

Reports on ground-water resources of areas adja­cent to Upton Count', are, by county: Crane (Shafer,1956); Crockett (Iglehart, 1967); and Ector (Knowles,1952).

The geologic formations in Upton County weredescribed by Sellard~; and others (1932) and Jones(1953). The latter report contains an extensive bibliog­raphy of the numerou i papers pertaining to the regional

geology.

Economic Development

The economy l)f Upton County is dependentlargely upon the production of oil and gas, but is alsosupported by income from sheep, cattle, and irrigatedfarm production. Ground water is basic to the economyof the county. All water for public supply, industry,irrigation, domestic supply, and nearly all water forlivestock is pumped from wells.

- 4·

In 1925, oil was discovered south of King Moun­tain in the southwestern part of the county. Theresulting boom increased the population from 253 in1920 to 5,968 in 1930. The city of McCamey quicklydeveloped as a base for the oil-field operations. In a fewmonths, a city of ten thousand was housed in tents andhastily constructed frame buildings. A law force of oneranger had difficulty in preserving order. Water hauled totown brought one dollar a barrel (Webb, 1952, p. 101).

A second oil boom that began in the late 1940'ssubstantially revitalized the economy of the county.According to the records of the Railroad Commission ofTexas (1966), 128 oil and gas fields (including multiplecounty fields) have been delineated during the periodfrom 1950 through 1965.

Development of irrigated farming, begun in theMidkiff area during the early 1950's, has also con­tributed to the economy of the county. Acreage underirrigation increased from 550 in 1958 to 2,810 in 1964(Gillett and Janca, 1965, p. 281). The principal crops aregrain and forage sorghum, oats, barley, wheat, cotton,and pasture grasses.

Topography and Drainage

The principal topographic features in UptonCounty are (1) a relatively undissected plateau in thenortheastern half of the county, (2) a southwest-facingescarpment called Concho Bluff in the northwest part ofthe county, and (3) seven flat-topped "mountains" in thesouthern and southwestern parts.

The plateau is underlain by limestone strata, andthe surface is covered by a veneer of caliche and siltyclay loam. The surface slopes southeasterly at about 8feet per mile, which is also the approximate directionand rate of dip of the underlying limestones. Thealtitude ranges from 2,650 feet in the east-central part ofthe county to about 2,900 feet in the northwest corner.

The surface is characterized by numerous smalldepressions and a few small eastward-flowing ephemeralstreams tributary to the Middle Concho River. Drainageof the surface is primarily interior; very little waterreaches the streams. Drainage from the escarpment alongthe southwestern edge of the plateau is toward the PecosRiver to the south and west.

The topography in the southern and southwesternparts of the county is characterized by broad, flat­topped ridges, mesas, and buttes that are underlain byresistant limestone strata. Altitudes range from about2,300 feet along Fivemile Creek at the southern bound­ary of the county to 3,125 feet at King Mountain, thehighest point in the county. The areas of higher altitudesare separated by wide valleys that are drained bytributaries of the Pecos River. These streams flow only

SO 100 M....

I.'.'·---1 !~.- - - rou;;l.-

Location

Figure I

of Upton County

u.s. GBological Survey in

and the

cooperation with the

Commissioners Court

- 5 -

Texas Water Development

of Upton CountyBoard

during periods of heav'{ rainfall and most of the runoff isabsorbed by the alluvial deposits.

Climate

These are the last two digits of the well number. Inaddition to the 7-digit well number, a 2-letter prefix isused to identify the county. The prefixes for Upton andadjacent counties are as follows:

The climate of Upton County is semiarid and ischaracterized by a wiele range in temperature and a highrate of evaporation.

COUNTY PREFIX

Crane H H

Crockett HJ

COUNTY PREFIX

Midland T J

Reagan UZ

Acknowledgments

Thus, well YL-45-46-601, which is owned by the JacobLivestock Co., is in Upton County (YL), in the 1-degreequadrangle 45, in the TY2-minute quadrangle 46, in the2%-minute quadrangle 6, and was the first well (01)inventoried in that 2%-minute quadrangle (F igure 4).

Water-level, pumpage, and completion data forindustrial water-supply wells were generously furnishedby the Trinity Water Co. and by staffs of the Gulf OilCorp. at Crane, Texas, Humble Oil and Refining, Mobil,Phillips Petroleum, Shell, and Sohio oil companies atMidland, and EI Paso Natural Gas Co. at Jal, NewMexico.

The author is indebted to the many ranchers,farmers, and oil-company personnel for supplying infor­mation about their wells and permitting access to theirproperties; to the well drillers for logs and otherinformation on water wells; and to the officials of thecities of Rankin and McCamey for municipal pumpagedata. Appreciation is expressed for support given bymembers of the Upton County Commissioners Court,headed by Judge Allen Moore, and for aid contributedby Dub Day, county agent, and Jim Haralson of the SoilConservation Service of the U.S. Department of Agri­culture, all of whom maintained a strong interest in theprogress of the project.

YLUptonJHEctor

Well-Numbering System

The records 0 1: the U.S. Weather Bureau atMcCamey, which date from 1933, provide the mostcomplete climatological data for the county. Annualprecipitation from 1933 to 1965 (Figure 2) averaged12.55 inches. The period maximum, 28.98 inches,occurred in 1941; the period minimum, 5.57 inches,occurred in 1953. Normally, about 72 percent of theannual precipitation falls in the 6-month period fromMay through October (Figure 3). The highest recordedprecipitation for 1 month was 8.49 inches in September1964.

The average annual gross lake evaporation forUpton County is about 83 inches (Kane, 1967), or morethan six times the average annual precipitation. Evapora­tion rates are highest during the summer when the soilmoisture demand of plants is also large.

Precipitation ha~; been measured at Rankin since1948, but available "ecords are incomplete prior to1963. During the period 1963 through 1965, the annualprecipitation averaged 14.78 inches at Rankin and 12.65inches at McCamey.

The average monthly temperature at McCameyranges from 46.5°F in January to 84.9°F in July (Figure3). The yearly averagE! temperature is 66.9° F, and therecorded extremes art~ 113°F and _2° F. The ~Jrowing

season is about 230 dcys. The approximate dates for thelast and first killing frosts are March 26 and November12.

The well-numbering system used in this report,based on the divisiom, of latitude and longitude, is theone adopted by the Texas Water Development Board forLIse throughout the State (Figure 4). Under this system,each 1-degree quadran~le in the State is given a numberconsisting of two digits; Upton County includes parts ofquadrangles 44 and 45. These are the first two digitsappearing in the well number. Each 1-degree quadrangleis divided into 7%-minute quadrangles which are given2·digit numbers from 01 to 64. These are the third andfourth digits of the well number. Each 7%-minutequadrangle is subdivided into 2%-minute quadranglesgiven a single digit number from 1 to 9. This is the fifthdigit of the well number. Finally, each well within a2%-minute quadrangle is given a 2-digit number in theorder in which it was inventoried, starting with 01.

Ed L. Reed, consulting hydrologist, Midland,provided a large amount of the pumping-test dataincluded in Table 2.

GEOLOGY AS RELATED TO THEOCCURRENCE OF GROUND WATER

General Stratigraphy and Structure

The geologic units that yield water suitable formost purposes range in age from Triassic to Recent. Thethickness, lithology, and water-bearing properties ofthese units are discussed in detail in the followingsection, and are summarized in Table I. The areal extent

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30 r-------------------------

1965~960

Average annual 12.55 inches

19551950194519401935

25 t-----------t'7'7f------------------~

20 t----------f7':;4------------------~

enl.LJ::I:~ 15 t---------¥rl----+~'+-------~~-----~---~

Figure 2

Annual Precipitation at McCamey, 1933- 65

US. Geological Survey in cooperation with the Texas Water Development Board

and the Commissioners Court of Upton County

- 7 .

gO ~-r----.-~-.--r---r----r----r----.--....,......--r--,....---.Average annual

66.90F80

.....W

~ 10~--------.~------------"~-------lwa:Iex 60lL.

(/)

~ 50~-~:""------------------~~a:~

w0 40

30 L---.J~---.l._---l._.-L_......J...._--L_--L_....L_-L.._..L-_..l..-----lJon. Feb. Mol'. Apr. May June July Aug. Sept. Oct. Nov. Dec.

Average monthly temperature at McCamey, 1933 -65

12~--------------------------,

Average annual83 inches

10~------------+???%%~~;4t_------__j

8l------------Ifflffl~~~44..::;~~ffl4_----____1

(/)wG 4 ~--~fflfflffl'~%%%%~~~~~fflmm%7f____lz

o Jan. Feb. Mol'. Apr. May June July Aug. Sept. Oct. Nov. Dec.

Average monthly gross lake-surface evaporation inUpton County, 1940-65 (Kane, 1967)

(/)WIIUZ

2 r-------.---:::==-----------------,Average annual 12.55 inches

oto..:::..:::..:...:::.JL..:l..::..::...::...::.J:::...:...::...:~~:~~:::...:::..L~~~~~~~~~~~~~

Jon. Feb. Mol'. Apr. May June July Aug. Sept. Oct. Nov. Dec.

Average monthly precipitation at McCamey, 1933- 65

Figure 3

Average Monthly Temperature and Precipitation at Mc Carney

and Gross Lake Evaporation in Upton County

U. S. Geological Survey in cooperation with the Texas Water Development Boardand the Commissioners Court of Upton County

- 8 -

Figure 4

Well- Numbering System

U. S. Geological Survey in cooperation with the Texas Water Development Board

and the Commissioners Court of Upton County

- 9 -

Table 1.--Geologic Units and Their Water-Bearing Characteristics, Upton County and Adjacent Areas

ERA SYSTEM

Cenozoic ~uaternary

------t-I

SERIES ~T-=~-Recent to I

Pleistocene

Washita

STRATIGRAPHICUNIT

Alluvial and eoliandeposits

APPROX HIATEMAXIMUM

THICKNESS(FT)

200

250

CHARACTER UF ROCKS

Cal iche, clay, sand and gravel.Locally mantled with windblownsilt and sand.

Massive to thin-bedded lime­stone and calcareous clay andmarl.

WATER-BEARING CHARACTERISTICS

Yields small quantities of freshto slightly sal ine water to live­stock and domestic wells along~tre~~ ~0~r5e5 in th~ ~0uthprn

and western parts of the county.

Not an aquifer in Upton County.

I I I -----+-·-------+I-------+I--------------f----------------

.:..o

Cretaceous

Mesozoic

Triassic

Comanche Fredericksburg

Trinity

Dockum

Kiamichi FormationEdwards LimestoneComanche Peak

Li mes tone

Trinity Sand

Chinle Formationequivalent

Santa RosaSandstone

Tecovas Formation

270

275

570

560

270

Calcareous clay, marl, and palegray to yellowish-brown mas­sive, nodular, fossiliferouslimestone. Yellowish-brownargillaceous limestone at base.

Buff to gray, fine- to medium­grained sand and sandstoneinterbedded with subordinateamounts of red, gray, and pur­ple shale. Fine gravel at basein some areas.

Brick-red to maroon and purpleshale; thin discontinuous bedsof red or gray sandstone andsiltstone.

Reddish-brown to gray, medium­to coarse-grained, micaceous,conglomeratic sandstone inter­bedded with shale.

Red shale, siltstone, and fine­grained sandstone.

All strata are above the water­table except near the south­eastern edge of Upton Countywhere the lower beds yieldsmall quantities of fresh waterfrom joints and fractures to afew wells.

The principal aquifer in UptonCounty. Yields small to moderatequantities of fresh to slightlysaline water to several hundredwells.

Yields small quantities of freshto moderately saline water towells in the western and south­western parts of the county.

Yields small quantities ofslightly to moderately salinewater to shallow wells in thesouthwestern part of the county.Small to moderate quantities ofmoderately to very saline waterhave been pumped from deep wellsin the northern part of thecounty.

Not known to yield water towells in Upton County.

(Continued on next page)

Table l.--Geologic Units and Their Water-Bearing Characteristics, Upton County and Adjacent Areas--Continued

APPROXIMATESTRATIGRAPHIC I MAXIMUM

ERA I SYSTEM I SERIES I GROUP I UNIT I TH ICKNESS CHARACTER OF ROCKS WATER-BEARING CHARACTERISTICS(FT)

Thin-bedded siltstone and Not known to yield water togypsum. I wells in Upton County. Probably

Dewey Lake Redbeds I 230 I capable of yielding smallamounts of moderately salinewater in the southwestern part

Iof the county.

OchoaAnhydrite, dolomite, and lime- Not known to yield water tostone interbedded with sand wells in Upton County. Probably

Rustler Formation I 150 I and shale. capable of yielding smallamounts of moderately saline tovery saline water.

Salado Formation I 850 I Salt (halite), anhydrite, ~known to yield water tosylvite and polyhalite. wells in Upton County.

Paleozoic I Permian I I ITansill Formation Dolomite, anhydrite, sand- Not known to yield water toYates Sandstone stone, shale, and some salt. wells in Upton County. ProbablySeven Rivers 2,050 capable of yielding small

Formation amounts of very saline or brine.... I I I I Queen Formation water •....

Guadalupe Artesia ITan to brown dolomite. Fine- Yields small quantities of

Grayburg to medium-grained sandstone moderate to very saline sulfurFormation 270 with subordinate amounts of water in conjunction with oil.

bentonite and anhydrite.

Guadalupe

I I IILimestone and gray do 10m; te Yields moderate quantities of

and San Andres with sandstone and inter- a sulfurous brine to wells forLeonard Limestone 1,100 bedded black shale. waterflood operation in the

northern part of the county.

of these units and the locations of selected wells areshown on Figure 19; the subsurface relationship of theserocks are shown by geologic sections A-A' and B-B'(Figures 20 and 21). Rocks of Permian age are signifi­cant principally because they are the source rocks for oiland gas, but they fL.. rnish most of the saline waterpresently (1967) being used in the secondary recovery ofoil. Although these rocks are not discussed in this report,their physical charactt!ristics and water-bearing proper­ties are summarized in Table 1.

The most prominent geologic structures in UptonCounty are the Central Basin Platform, a structural highin the southwestern corner of the county, and theMidland Basin, a structural depression underlying therest of the county. Both of these features are subdivi­sions of the more exte:lsive Perm ian Basin (F igu re 5). Asshown in section A-A (F igure 20), the pre-Cretaceousstrata are relatively thin and flat-lying on the CentralBasin Platform; the strata thicken and dip sharplybasinward along the flanks of the platform, and arethickest in the Midland Basin. In contrast, the Creta­ceous strata dip gently toward the southeast (sectionB-B', Figure 21) and do not appreciably reflect theunderlying platform-basin structure.

Physical Characteristics and Water-BearingProperties of the Geologic Units

Triassic System

Dockum Group

The Dockum Group is divided into the TecovasFormation, the Santa Rosa Sandstone, and the ChinleFormation equ ivalent in ascending order. The uppersection of the Dockum Group is exposed in smallscattered outcrops in the Pecos River valley west ofUpton County. Hoots (1926, p. 96) described 95 feet ofthe uppermost part of the Dockum at Red Point, 15miles northwest of McCamey and 2Y2-miles west of theCrane-Upton County line. At Red Point, Hoots alsomeasured 182 feet of overlying Cretaceous strata andprovisionally placed the Triassic-Cretaceous contact atthe top of the highest bed of red clay.

The Dockum Group is almost the exact equ ivalentof the Chinle Formation of the Colorado Plateau region(Reeside and others, 1957, p. 1476). Because of localusage, however, Garza and Wesselman (1959, p. 18) inWinkler County and Armstrong and McMillion (1961, p.37) in Pecos County included only the upper part of theDockum Group as the equivalent of the Chinle Forma­tion of the type area. The restricted "Chinle Formationequivalent" terminology used in the above reports isused in this report.

In general, the chemical quality of the water isclassified according to the dissolved-solids content(Winslow and Kister, 1956, p. 5) as follows:

In the description of the water-bearing propertiesof geologic units, the yields of wells are describedaccording to the following rating:

DESCRIPTION

Small

Moderate

Large

DESCR IPTION

Fresh

Slightly saline

Moderately saline

Very saline

Brine

YIELD(GALLONS PER MINUTE)

Less than 50

50 to 500

More than 500

DISSOLVED-SOLIDS CONTENT(PARTS PER MILLION)

Less than 1,000

1,000 to 3,000

3,000 to 10,000

10,000 to 35,000

More than 35,000

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Tecovas Formation

The Tecovas Formation consists of red shale,siltstone, and fine-grained sandstone. The Tecovasunconformably overlies the Dewey Lake Redbeds, theuppermost formation of the Permian System. litho­logically, the two formations are similar and are oftenlumped together under the general term "Permian­Triassic redbeds." The thickness of the Tecovas rangesfrom 150 feet to 270 feet in the Midland Basin. On theCentral Basin Platform in the southwestern corner of thecounty, the Tecovas is overlapped by the Santa RosaSandstone (F igure 20).

The Tecovas Formation is not known to yieldwater to wells in Upton County.

Santa Rosa Sandstone

The Santa Rosa Sandstone consists of reddish­brown to gray, medium- to coarse-grained, micaceous,well-cemented conglomeratic sandstone interbeddedwith shale. On the Central Basin Platform in thesouthwestern corner of Upton County, the Santa Rosa,about 100 to 160 feet thick, is underlain by the DeweyLake Redbeds and overlain by the Chinle Formationequ ivalent in some places, and by Quaternary alluviumin other places. From the flanks of the Central BasinPlatform, the formation dips and thickens northeast­ward. In the Midland Basin, the formation is 360 to 560

feet thick and is underlain by the Tecovas Formationand overlain by the Chinle Formation equ ivalent. Depthsto the top of the formation range from 10 feet in thesouthwestern corner of the county to 750 feet along thenorth-central edge of the county.

The Santa Rosa Sandstone yields small quantitiesof slightly to moderately saline water to shallow wells inthe southwestern part of Upton County. Most of thewater is pumped for livestock supply, and very little issuitable for human consumption. In northern UptonCounty, small to modHrate quantities of moderately tovery saline water have Jeen pumped from 14 deep wellsfor the secondary recovery of oil. These wells screen a200-foot section of well cemented sandstone and con­glomerate in the lower part of the formation.

Chinle Formation Equi!Ialent

The Chinle Formation equivalent consists ofbrick-red to maroon and purple shale and lenticular bedsof fine-grained red or Hray sandstone and siltstone. Theformation underlies a II of Upton County except thesouthwest corner wher,~ it has been removed by erosion(F igure 20). The formcltion has a thickness ranging froma few feet in places on the Central Basin Platform to asmuch as 570 feet in the Midland Basin. The base of theformation is conformable with the underlying SantaRosa Sandstone; the top, however, has been subjected toerosion and is overlain with angular unconformity byeither basal Cretaceous sand or Quaternary alluvium.

In western and southwestern Upton County wherethe Trinity Sand is clbsent, the thinly bedded discon­tinuous beds of sandstone of the Chinle Formationequ ivalent yield small quantities of fresh to moderatelysaline water to a few domestic and livestock wells.Elsewhere, the formation has not been tapped becausewater can be obtained from shallower depths. Further­more, the relatively ,mpermeable clay and shale bedsretard downward percolation of water into the under­lying beds of sand, which according to drillers' reports,are frequently dry. Drillers also report that the shalestend to "ball up" on the drilling bits and then cave intouncased wells.

Cretaceous System

Rocks of Cretaceous age crop out in, or underlie atshallow depths, most of Upton County. The youngestCretaceous rocks belong to the Washita Group and capthe more prominent mesas, buttes, and ridges in thesouthern part of the county; elsewhere in the county,they have been remolted by erosion. Limestones of theunderlying Fredericksburg Group cap the lower buttesand benches in the southeastern half of the county andsupport the plateau surface in the northeastern half.Sandstone at the baSl~ of the Cretaceous System, either

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Fredericksburg or Trinity in age, crops out on the lowerslopes of the upland features. The Cretaceous rocks arethickest (about 700 feet) near the summit of Noltke(Noelke) Hill, 6 miles south of Rankin. About 600 feetof Creta ceous rocks were penetrated in wellYL-45-55-102 (Figure 19) on King Mountain north ofMcCamey. At McCamey and in much of the south­western half of the county, headward erosion by thetributaries of the Pecos River have removed all theCretaceous rocks and a part of the underlying rocks ofthe Dockum Group.

Trinity Sand

The term "Trinity Sand," as used in this report,refers to the Maxon Sand and the Basement sands of P.B. King (1930, p. 92-93) and to the basal Cretaceoussandstone of Adkins (1927, p. 31-33). The term haswidespread usage in west Texas even though fossilevidence (Adkins, 1927, p. 33) indicates that at least theupper part of the "basal Cretaceous sandstone" is ofFredericksburg age. The lower part of the unit, accord­ing to King (1930, p. 93), is probably of Trinity age.

In Upton County, the Trinity Sand crops out in anarrow band at the base of the irregular but generallycontinuous escarpment that marks the dissected perim­eter of the Edwards Plateau. The formation is alsoexposed near the base of several isolated mesas andbuttes in the southwestern part of the county (Figure19).

The Trinity Sand consists of buff to gray, fine- tomedium-grained, crossbedded quartz sand and sandstoneinterbedded with lesser amounts of red, gray, and purpleshale. A fine gravel occurs locally at the base of theformation. I n some places the sand is tightly cemented;in other places it is loose or poorly cemented andcommonly is referred to as "pack sand" by local drillers.

The Trinity Sand has a maximum thickness of 215feet in north-central Upton County, but elsewhere in thecounty the thickness normally ranges between 120 and180 feet. The variations in thickness are due principallyto the irregularly eroded Triassic surface upon which theformation was deposited.

The approximate altitude of the top and base ofthe Trinity Sand in Upton County is shown on Figures 6and 7. As shown by Figure 6, the top of the formationdips southeasterly at an average rate of about 10 feet permile. I n most of the northeastern half of the county, thetop of the formation ranges from 60 to 150 feet belowthe land surface; however, in the southern and south­western parts of the county, where the topography isvery irregular, the top is as much as 450 to 500 feetbelow the summits of the highest mesas and ridges.

The Trinity Sand, the principal aquifer in thecounty, yields small to moderate quantities of fresh toslightly saline water to several hundred wells for publicsupply, irrigation, industry, domestic supply, and live­stock.

Fredericksbu'rg Group

The Fredericksburg Group is divided into theComanche Peak Limestone, Edwards Limestone, andKiamichi Formation in ascending order (Adkins, 1927,p. 37). In Upton County the group has a maximumthickness of about 270 feet and consists of yellowish­brown, massive nodular fossiliferous limestone, calcar­eous clay, and marl. Eargle (1956, p. 9) measured a fullsection of the Fredericksburg Group on the south side ofKing Mountain. 0 n the basis of fossils, he assigned thelower 168 feet of predominately Iimestone to theComanche Peak and Edwards Limestone, undifferen­tiated, and the upper 93 feet of calcareous clay and marlto the Kiamichi Formation.

The Fredericksburg Group lies above the watertable except near the east-southeastern edge of thecounty. Wells that tap the underlying Trinity Sand inthat area, particu larly those wells that have surfacecasing only, may d,-aw water from the lower 5 to 25 feetof the Fredericksburg Group. One well, YL-44-42-901, isknown to tap a water-bearing zone that is perched abovethe regional ground-water reservoir in the Trinity Sand.

Washita Group

Rocks of the Washita Group crop out on the upperslopes and cap the summits of seven flat-topped"mountains" in southern and southwestern UptonCounty; elsewhere in the county, these rocks have beenremoved by erosion. On the south side of King Moun­tain, the most prollinent of the erosional remnants, theWashita Group consists of, in ascending order, 54 feet ofcalcareous clay and marl, 22 feet of marl and thin­bedded limestone, and about 120 feet of thick-beddedto massive limestone. The upper part of the resistantlimestone is commonly called the "caprock." A welldeveloped system of nearly vertical joints and fracturescauses the Iimestone beds of the caprock to weather to acharacteristically blocky outline. The clay and marl bedsin the lower part are poorly ex posed on the slopes belowthe caprock.

In Upton County, the Washita Group lies abovethe water table. During storms, precipitation and surfacerunoff infiltrate the joints and bedding-plane crevices inthe limestone. However, most of this water is dischargedthrough seeps and small springs near the base of thecaprock, and only a small part of the water percolatesdownward through the clay and marl beds in the lower

- 19 -

part of the Washita and upper part of the FredericksburgGroups to the ground-water reservoir in the TrinitySand.

Quaternary System

Pleistocene and Recent Series

Alluvium and Eolian Deposits

Alluvium of Pleistocene and Recent ages restsunconformably on rocks of Triassic and Cretaceous agein stream valleys in Upton County. The alluvium consistsof clay, sand, gravel, and caliche-material that has beeneroded largely from Cretaceous rocks. The deposits arepoorly sorted and are generally unconsolidated. Locally,however, indurated caliche and caliche-cemented gravelsresembling hard Cretaceous limestone occur. The alluvialdeposits are thinnest where they wedge out against theoutcrops of older rocks on the valley walls. In the upperreaches, the alluvium of creeks and draws is relativelythin and gravelly, but gradually becomes thicker andfiner-grained downstream. The alluvium is thickest(about 200 feet) in the valley of Fivemile Creek near theUpton-Crockett County line.

Alluvial deposits yield small quantities of fresh toslightly saline water to livestock and rural domestic wellsalong stream courses in the southern and western partsof Upton County.

Windblown sand of Recent age mantles alluvialdeposits in valleys crossing the Upton-Crane County line.The thicker deposits, called sandhills, cover about1Y:z-square miles in Upton County, and extend westwardinto Crane County and northwestward through parts ofWard, Winkler, Ector, and Andrews Counties into NewMexico. In Upton County, the sand has a maximumthickness of about 20 feet in the sandhill area shown onFigure 19. Thin-less than 3 feet-eolian deposits alsoform sparsely vegetated low hummocks in areas adjoin­ing the sandhills, and soil of eolian origin mantles mostof the surface in the northeastern half of the county.

The eol ian deposits are above the water table;consequently, they are not sources of water.

Aquifers

A formation, group of formations, or a part of aformation that is capable of yielding usable quantities ofwater is termed an aquifer. Most of the ground waterused in the county for municipal, domestic, livestock,and irrigation supplies, and a part of that for industrialneeds is obtained from three aquifers: The Trinity Sand,Santa Rosa Sandstone, and the alluvium. The Chinle

Formation equivalent is of minor importance, yieldingsmall quantities of wa1er to a few wells in the westernand southwestern parts of the county. The mainfunction of the Chinle is to retard the movement ofwater from the overlying Trinity Sand to the underlyingSanta Rosa. The deeper aqu ifers, such as the San AndresLimestone, are important primarily as a source of salinewater for the secondary recovery of oil, or as theypertain to the possible contamination of the overlyingaquifers.

The principal aquifer in the county is the TrinitySand. It underlies all the northeastern half of the countybut is absent in much of the southwestern half. TheSanta Rosa Sandstone has no lateral boundaries in thecounty although it thins substantially over the CentralBasin Platform in the southwestern corner of thecounty.

GROUND-WATER HYDROLOGY

The general principles of ground-water hydrologyas they apply to the study area are discussed in thefollowing report sections. For additional technical infor­mation and other hydrologic principles, the reader isreferred to: Meinzer (1 923a, 1923b), Meinzer and others(1942), Todd (1959), Tolman (1937), and Wisler andBrater (1959); and for nontechnical discussions to:Leopold and Langbl:!in (1960) and Baldwin andMcGu inness (1963).

Source and Occurrence of Ground Water

The source of ground water in Upton County isprecipitation in the county and in areas mainly to thenorth and west. Most of the precipitation is evaporatedat the surface or is transpired by vegetation. I n normalyears only a small amount runs off into streams. Waterthat escapes runoff, evaporation, and transpirationmigrates slowly dowrward by gravity through the zoneof aeration until it reaches the zone of saturation. In thezone of saturation, a I the voids and pore spaces in therocks are filled with water. The surface of this zone iscalled the water tablH, and the water within it is calledground water.

Ground water in Upton County occurs under twoconditions-water table, or unconfined; and artesian, orconfined. Under watl~r-table conditions, the water willnot rise in wells above the level at which it is found inthe formation; under artesian conditions, the water risesto a level above the top of the formation.

The water in the Trinity Sand is generally uncon­fined. However, in the southeastern corner of the countywhere the formation is fully saturated and a zone of lowpermeability occurs near the base of the overlyingFredericksburg Group, wells tapping this aquifer have as

- 20-

much as 25 feet of artesian head. Some of the wellsrelease H2S gas which has been entrapped in the aquiferby the overlying confining layer.

The Santa Rosa Sandstone is an artesian aquifer inwhich the water is confined by the less permeablematerial of the overlying Chinle Formation equivalent.The pressure in the Santa Rosa is sufficient to cause thewater in a tightly cased well, for example, wellYL-44-18-710, to rise nearly 690 feet above the top ofthe formation, or 175 feet below the water table in theTrinity Sand. Where the Chinle is absent, as over theCentral Basin Platform in the southwest corner of thecounty, the Santa Rosa and the alluvium are in contact,forming in effect a single unconfined aquifer.

The aquifers older than the Santa Rosa are underartesian pressure. Reportedly, the hydrostatic pressure inthe San Andres Limestone was sufficient to cause thewater to rise in well TJ-45-23-907 in Midland County(F igure 19) to within 120 feet of the land surface in1955.

Recharge, Movement, and Discharge

The aqu ifers underlying Upton County arerecharged naturally by infiltration from precipitation inthe county or in counties to the north and west and byseepage from streams and lakes. The direct infiltration ofrainfall probably is negligible because most of theprecipitation is evaporated or transpired by plants.Hence, recharge occurs only when storms provide morethan enough water to restore the soil moisture to fieldcapacity.

Recharge to the Trinity Sand is small, considerablyless than the quantity of water pumped from the aquiferin 1966. The quantity of water mov ing through theaqu ifer is roughly equivalent to the recharge. On thebasis of the ability of the aquifer to transmit water (thecoefficient of transmissibility) and the present (1966)hydraulic gradient (10 feet per mile), approximately 1mgd (million gallons per day) or about 1,100 acre-feetper year is mov ing through the aqu ifer. The amou nt ofrecharge necessary to replace the water moving throughthe aquifer is equ iva lent to less than one-fourth inch ofprecipitation on that part of the county underlain by theTrinity Sand. This value agrees with that reported byTheis (1964, p. 332) for the heav ily irrigated southernHigh Plains north of Upton County. Because of the smalloutcrop area of the Trinity Sand and the low perme­ability of the surficial material, a large part of therecharge to the Trinity Sand probably occurs outside thecounty; only a small amount can be attributed to theinfiltration of streamflow.

Recharge to the Trinity Sand and to the alluviumfrom streamflow occurs principally in the southern and

southwestern parts of the county. The rapid rise in waterlevels in well YL-44-49-301 (Figure 14), following theheavy precipitatior in the spring of 1965, is due torecharge from Rankin Creek and its tributaries.

The principal areas of recharge of the ChinleFormation equ ivalent and Santa Rosa Sandstone are incounties to the r,orth and west. An unknown butprobably small amount of water is added to theseaqu ifers in the sO'Jthwestern part of Upton Cou ntywhere they are locally in hydrologic continuity with thealluvium.

Ground water in Upton County moves slowly,probably 10 to 100 feet per year, through the aquifersfrom areas of recharge to areas of dischar~Je, grav itybeing the motivating force. Initially, the movement isdownward in the areas of recharge; thereafter,. the watermoves in the general direction of the dip of theconsolidated aquifHs, and parallel to the slope of theland surface in the alluvial deposits. Exceptions to thedowndip and dowrslope movement of water are in theareas where large quantities of water are withdrawn fromthe aqu ifers. I n those areas, water moves from alldirections to the centers of heavy pumping.

The general direction of movement of groundwater in the coumy is shown by the altitude of thewater levels in wells tapping the Trinity Sand andQuaternary alluviurn, and Chinle Formation equivalentand Santa Rosa Sandstone where the latter two forma­tions occur at shallow depths in the southwestern part ofthe county (Figure 8). The map represents a compositeof the water level" of the aqu ifers tapped; thus, thewater level at any particular location may be somewhatdifferent than that :ihown on the map. The movement ofwater is in the dire(:tion of decreasing altitude and is atright angles to the contours. Accordingly, the groundwater moves southeasterly except in the southwesternpart of the cou nty where it moves southwesterly to thePecos River.

Ground water in Upton County is discharged bothnaturally and artificially. The only apparent naturaldischarge is from evapotranspiration in those areas inwhich the water table is near the land surface; noperennial springs e,r effluent seepage were reported orobserved in the county.

Ground water is discharged artificially by wells.(See section on "Use of Ground Water.") In 1965, thedischarge from all wells in the county amounted to3,928 acre-feet (3.5 mgd).

The transfer of water from one aqu ifer to anotheris neither discharge nor recharge, but only an incident ofground-water mOVE!ment. Some water moves from theTrinity Sand intci the Quaternary alluvium in thesouthwestern half of the county as indicated by thecontours in Figure 8; an equally small amount of watermoves downward from these aquifers into the ChinleFormation equ ivalent and Santa Rosa Sandstone.

- 21 -

Hydraulic Properties of the Aquifers

Aqu ifer tests were made on a few wells in UptonCounty to determine the coefficients of permeability,transmissibility, and storage, which govern the ability ofthe aquifer to transmit, yield, or store water.

The field coefficient of permeability is the flow ofwater in gallons per day at the prevailing temperaturethrough a cross section of 1 square foot of the aquiferunder unit hydraulic gradient.

The coefficient of transmissibility, a similar mea­sure for the entire thickness of the aqu ifer, is defined asthe rate of flow of water in gallons per day at theprevailing water temperature through a vertical strip ofthe aquifer 1 foot wide extending the full height of theaquifer under a hydraulic gradient of 1 foot per foot.The volu me of water that wi II flow each day througheach foot of the aqu ifer is the product of the coefficientof transmissibility and the hydraulic gradient. Thesmaller the coefficient of transmissibility, the greater thehydrau Iic grad ient must be for the water to movethrough the aquifer at a given rate.

The coefficient of storage is the volume of waterreleased from or taken into storage per unit surface areaof the aquifer per unit change of the component headnormal to that surface. Under water-table cond itions,the coefficient of storage is practically equal to thespecific yield. The specific yield is the quantity of waterthat a formation will yield under the force of gravity, ifit is first saturated and then allowed to drain, the ratiobeing expressed in percentage of the volume of thiswater to the volume of the material drained.

The results of 21 aquifer tests in Upton Countyare given in Table 2. Of these tests, 20 were in wellstapping the Trinity Sand and one was in a well tappingthe Chinle Formation equivalent. Data for 16 of theaquifer tests in the Midkiff area were provided by Ed L.Reed, consulting hydrologist, Midland, Texas. Thesedata and those from the five aqu ifer tests that wereconducted during the current investigation were ana­lyzed by one or more of the following methods: TheTheis non-equilibrium method (Theis, 1935, p.519-524), the Cooper and Jacob straight-I ine method ofapproximation (Cooper and Jacob, 1946, p. 526-534),and the Theis recovery method (Wenzel, 1942, p.94-97). The field coefficients of permeability shown inTable 2 were determined by dividing the transmissibilitycoefficients by the estimated thickness of sand supplyingthe water to the well. The sand thicknesses wereobtained from a study of drillers' logs or electrical logs.

The coefficients of transmissibility determinedfrom the wells tapping the Trinity Sand ranged from lessthan 1,000 to 10,000 gpd (gallons per day) per foot; allbut two were less than 3,500 gpd per foot. The testsindicate that generally a transmissibility of less than1,000 gpd per foot can be expected from the Trinity in

Table 2.--Coefficients of Permeability and Transmissibility Determined from Pumping Tests of Selected Wells in Upton County

AQUIFER DATE TEST PRODUCING FIELD COEFFICIENT COEFFICIENT OF YIELDWELL (WATER-BEARING BEGAN INTERVALS OF PERMEABILITY TRANSMISSIBI L1TY (GPM) REMARKS

FORMATION) (FT) (GPO PER FT2) (GPO PER FT)

Y L-44-26-1 04 Trinity Sand Feb. 15, 1962 120-285 106 10,000 300 Recovery test. 1

44-26-110 do July 3, 1963 180-310 57 5,500 240 Do.

44-26-505 do May 22,1961 193-293 -- 2,000 150 Do.

44-26-506 do Mar. 30, 1963 193-293 -- 2,400 151 Do.

44-26-508 do May 10, 1963 185-285 3,200 108 Do.

44-26-509 do Mar. 21,1963 205-305 -- 2,900 151 Do.

44-26-510 do Mar. 13,1963 180-280 -- 3,200 127 Do.

44-26-511 do Mar. 18, 1963 180-280 -- 2,300 104 Do.

44-26-512 do May 8, 1963 200-300 -- 3,000 100 Do.

44-26-513 do June 29, 1963 212-312 3,200 151 Do.

44-26-514 ClO Apr. 20,1963 228-328 2,500 100 Do.

44-26-515 do Mar. 28, 1963 223-323 -- 2,200 110 Do.

44-26-516 do June 21,1963 228-328 3,200 111 Do.

I".)44-26-517 do 225-325 -- 2,500 100 Do.I".)

44-34-203 do June 13,1963 132-315 16 2,700 151 Do.

44-34-204 do June 10,1963 1,100 131 Do.

44-41-907 do Sept. 13, 1966 80-210 14 1,400 -- I nterference test: Well Y L-44-41-905pumping 23 gpm.

44-49-209 do Nov. 24, 1965 20-170 13 900 36 Recovery test.

45-23-701 do Dec. 8, 1965 140-148 32 1,100 53 Do.195-218

45-23-702 do Dec. do 965 40-210 38 1,500 Interference test: Well Y L-45-23-701pumping 52.6 gpm.

45-46-603 Chinle Formation Mar. 8, 1966 428-490 8 360 36 Drawdown test.equivalent

1 Pumping test conducted by Ed L. Reed, Consulting Hydrologist, Midland, Texas.

and near its outcrop; 1,000 to 3,000 gpd per foot inmost of the northeastern half of the county; and from3,000 to (i,OOO gpd per foot in parts of the northeastcorner of the cOJnty. The field permeabilities deter­mined from the t~sts ranged between 13 and 106 gpdper sq uare foot.

A coefficient of transmissibility of 360 gpd perfoot and a field permeability of 8 gpd per square footwere obtained from a test made in well YL-45-46-603which taps the Chinle Formation equivalent. A storagecoefficient of 0.0004 was computed from this test.

The specific yield of the Trinity Sand could not bedetermined from the aquifer tests because of their shortduration. On the basis of specific yield or water-tableaquifers elsewhere a value of at least 10 percent seemsreasonable.

The yields 01 wells in Upton County also provide ageneral index of t'1e ability of the aquifers to transmitwater. The yields are in the small and moderate range.For purposes of this report, small yields are consideredto be less than 50 gpm (gallons per minute), andmoderate yields ar,~ 50 to 500 gpm. Many of the yields(Table 2) were reported and some were obtained duringthe development tests when wells commonly arepumped in excess of the sustai.ned yield of the aquifer.

The measured yields of wells in the Trinity Sandranged from less than 50 to 300 gallons per minute. Theyields of nine wells in the Santa Rosa that formerlysupplied a waternood project in the Midkiff areareportedly ranged 1rom 60 to 1909pm and averaged 115gpm. Yields ranging from 120 to 165 gpm have beenreported from five wells fapping the San Andres Lime­stone 8 to 10 miles south of Midkiff.

The specific capacity of a well is the ratio of theyield in gallons per minute to the observed drawdown ofwater level in the well in feet. Specific capacities areuseful in estimatin~! the coefficient of transmissibility inareas where aquifer tests are not available. I n general,high specific capacities indicate high transmissibilitiesand low specific capacities indicate low transmissibilities.However, other factors such as the amount of screened,slotted, or perforatt~d intervals and the manner in whichthe well is developed and maintained also affect thespecific capacity. The length of time that a well has beenpumped is also a factor. Because of the increase indrawdown with time (Figure 10), the specific capacityof a well decreases with time.

The specific capacities of 33 wells in the TrinitySand in Upton County ranged from 0.6 gpm/ft in wellYL-44-49-209 to 6.6 gpm/ft in well YL-44-26-104 andaveraged 1.8 gpm/ft. The specific capacities of 5 wellstapping the other aquifers were less than 0.5 gpm/ft.Well YL-45-46:603 in the Chinle Formation equivalenthad a specific capacity of 0.3; 2 wells in the Santa Rosahad specific capacites of 0.3 and 0.1; and 2 wells in theSan Andres had 0.2 and 0.1.

- 25-

The coefficients of transmissibility and storagemay be used to predict future drawdowns of water levelscaused by pumping. Figure 9 shows the theoreticalrelation of decline of water levels to distance from thecenter of pumping for different rates of discharge andtransmissibility. The calculations were based on anassumed storage coefficient of 0.1 and a pumping periodof 100 days. The 500 to 10,000 gpd per foot range intransmissibility is representative of the Trinity Sand inUpton County. Transmissibilities being as indicated, therates of discharge that were used to compute thedrawdown curves are representative of rates that can besustained in wells for 100 days or longer.

Figure 10 illustrates the theoretical relation ofdeclines to distance from the center of pumping andtime. It indicates that water levels are lowered bycontinued pumping, but that the rate of decl inedecreases with time. For example, with a well pumping60 gpm, the decline in an observation well 10 feet fromthe pumped well would be 30 feet after 100 days andabout 38 feet after 3 years. The total decline at anyoneplace within the cone of depression or influence ofseveral wells would be the sum of the influences of theseveral wells.

Use of Ground Water

Since the early 1950's, the demand for water inUpton County has increased markedly, the quantityused generally far exceeding that supplied by wells in thecounty (Figure 11). Because of the low annual rainfalland the lack of surface-water supplies, all the waterneeds of the county are supplied from aquifers not onlyin Upton County, but also from Reagan, Crane, Midland,Ward, Winkler, and Pecos Counties.

In 1965, water use amounted to 2,210 milliongallons (6,781 acre-feet), of which 941 million gallons(2,887 acre-feet) or about 42 percent was supplied bywells outside the county. Of the 1,280 million gallons(3,928 acre-feet) of water pumped from wells in UptonCounty, 91 percent or 1,170 million gallons (3,590acre-feet) was from the Trinity Sand. About two-thirdsof the ground water pumped in the county in 1965 wasused for irrigation. All irrigation was from wells in theTrinity Sand.

Public Supply

In 1965, Rankin and McCamey pumped 286million gallons (878 acre-feet), about 13 percent of allthe ground water used in the county. However, only thewater needs of Rankin are supplied from the ground­water sources in the county.

T= coefficient of transmissibility in gpd/ftQ =discharge, g pmS =coefficient of storage, 0.10

...",,~C +-I Time of pum ping =100 days ------------11

201 1

oIii ::::::IIIIIii*'::::=:a r:=z --== :::=a I

501,' I 1 1 I

I:::p<J ,c:::Pc ,c :::P' I101 1

I­wWl.L..

Z

Z 301 C ,~ , ,oQ

~<{0:::Q

N0)

10 100DISTANCE FROM PUMPED WELL, IN FEET

1000 10,000

Figure 9

Relation of Drawdown to Distance From Center of Pumping With Different

Discharges and Coefficients of Transmissibility

u. S. Geological Survey in cooperation with the Texos Water Development Board

and the Commissioners Court of Upton County

10I I 7' I 7' 7" ," I I

O. I i I ==-= I

201 I

to­WWL1..

Z

Z 301------~'-------7f'C---~

~ I I~ Coefficient of transmissibility(T)= 2000 gpd/ft« Coefficient of storage(S) = O. 10~ Discharge(Q) =60 gpm401-------:",e---7'--~1L-+-----------_,.__----------_+----------____j

/'\)'-J

10 100

DISTANCE FROM PUMPED WELL, IN FEET

1000 Iqooo

Figure 10

Relation of Drawdown to Distance From Center of Pumping and Time in an Aquifer

Having the Characteristics of the Trinity Sand

U S. Geological Survey in cooperation with the Texas Water Development Board and the Commissioners Court of Upton County

City of Rankin

Windmill wells supplied the water needs of theresidents of Rankin until 1939 when the city installed amunicipal water systt!m. At that time, the systemconsisted of one well h.3ving a capacity of about 70 gpm.The city added one well in 1948, when pumpingaveraged nearly 100,000 gpd, and a third well was addedin 1951, when pumpage increased to about 135,000 gpd.In 1965, Rankin was supplied by 10 wells owned by thecounty in a well field 2%-miles northeast of the city andby three wells in the municipal system. Pumping in 1965amounted to 94 millicn gallons, or slightly more than225,000 gpd. The wells, ranging in depth from 160 to242 feet and having a maximum total capacity of 560gpm (43 gpm per WEll average), are screened in theTrinity Sand.

City of McCamey

The municipal water system at McCamey consistsof five wells 15 miles southwest of the city in PecosCounty. The city's water supply has been previouslydescribed by Armstrong and McMillion (1961, v. I, p.69, 197) who wrote:

"The Texas Public Service Company oper­ated the first municipal water system of the city ofMcCamey, Upton County, using wells in PecosCounty. In 1928 the system was supplied by threewells (V-12, V-13, and V-14) tapping the 'TrinitySand: After the:ity assumed control of thesystem, one well (\1'-12) was abandoned and ~hree

new wells (V-9, V-l0, and V-11) were drilled,making a total of five 'Trinity Sand' wells in use.The yield per well i~; reported to range from 280 to350 gpm and to average about 300 gpm."

In 1965, municipal pumpage was slightly less than192 million gallons, or about 526,000 gpd; an additionalbut small amount of water was pumped from the 10 or15 domestic wells in and near the city, but this waterwas used primarily for lawn irrigation.

Industrial Supply

Industry in Upton County pumped about 242million gallons (743 acre-feet) of ground water fromwells in the county in "1965. Of this amount 141 milliongallons, or nearly 60 percent, was for waterfloodoperations and 86 million gallons (35 percent) was forgasoline plants and compressor stations.

Waterflood ing

Waterflooding, a method used in the secondaryrecovery of oil, involves the injection of water to theoil-bearing strata. I n some wells, the water is injected bygravity flow; in others, it is injected under pressureexerted at the well head. (A maximum surface pressureof one-half pound per square inch per foot of well depth

has been recommended by the Railroad Commission ofTexas.) Once injected, the water raises the pressure inthe oil reservoir and displaces the oil, forcing it to flowtoward the producing wells.

Water used for waterflooding consists generally of"production" and "extraneous" water mixed in varyingproportions. Production water is that which has beenseparated from the oil-water mixture pumped from theoil wells. Normally, production water is too saline forpurposes other than waterflooding; if not injected forsecondary recovery, it is disposed of as waste water.Extraneous water is derived from other sources such aswater wells and surface-water diversions. Extraneouswater may be fresh (although use of fresh water isdiscouraged), or it may be brine, and may requ iretreatment to be compatible with the fluids and gases inthe oil reservoir.

The first waterflood units in Upton County, thePegasus (Ellenburger) and Pegasus (Pennsylvanian) beganoperations in 1955. Three units were injecting water bythe end of 1961; another was started in 1962; sevenwere operating from 1963 through 1965; and three morehave been proposed. None of the units has beenabandoned, but injection in several has been sharplycurtailed.

Since 1955, about 3,000 million gallons (71million barrels or 9,152 acre-feet) of extraneous waterhas been used for waterflood operations in UptonCounty. Of this amount, 1,100 million gallons or nearlyone-third was from wells in Upton County; the rest wasfrom wells in Glasscock, Midland, Reagan, Ward, andWinkler Counties. The quantity, quality, and source ofground water pumped and used fo"r waterflood opera­tions during the period 1955-65 are shown in Figure 12.

The graph shows that during the period 1955-62,nearly all the water pumped in Upton County forwaterflood operations was from the Santa Rosa Sand­stone with only a small percentage from the San AndresLimestone. I n the period 1963-65, about 514 milliongallons or slightly more than one-fourth of all extra­neous water used in the county was pumped from wellstapping the Trinity Sand.

The volume of water used for waterfloodingreached a maximum in 1963 when 742 million gallonswas used, of which 342 million gallons or about 46percent was from 17 wells in Upton County. Use ofwater for th is purpose showed a downward trend, andby 1965, when 596 million gallons was used forwaterflooding, only 141 million gallons or about 24percent was from wells in Upton County. Of the 141million gallons, 43 million gallons or about 33 percentwas from 12 wells in the Trinity Sand; the rest was from5 wells in the San Andres Limestone.

- 28-

B200

. "A

500

" "

100

900

EXPLANATION

Geologic Dissolvedsource solids 2500

800

LJ San Andres..... Limestone >35,000 ppme •••

B

~ Capitan }Limestone

7005000-20,000

~Santa Rosa ppm

Sandstone 2000

600 -0 Trinity Sand<3000 ppm

enZ ." .0 A Ground water pumped in Upton .. 0...J County ., .,...J ". I:-et ., WC> B Total ground water used in .... w.. " .~ 500 Upton County (includes water ::.... ~

I0 pumped outside of County) ." . 1500 w.. " ..... a:en uz et0...J Z...J

~ 400 wC>

Z etQ..~

W ::>C> Q..

~ 1000~::> 300Q..

Figure 12

Qua ntlty, Quality, and Source of Ground Water Pumped

for Waterflooding, 1955-65

U. S. Geological Survey in cooperation with the Texas Water Development Boardand the Commissioners Court of Upton County

- 31 -

Gasoline Plants and Compressor Stations

In 1965, about 248 million gallons (761 acre-feet)of ground water was used in the operation of gasolineplants and compressor Hations in Upton County. Of thisamount, 115 million qallons (about 46 percent) wasfrom 17 wells in the county. Yields of the wells, allcompleted in the Trinity Sand, ranged from 20 to 96gpm and averaged 46 gpm.

Of the five gasolire plants in the county, four useda total of 218 million gallons, 85.5 million gallons ofwhich was from 11 wells in the county. The water needsof the Crossett plant, 4 miles west of McCamey, wassupplied from McCamey's water system.

The four compressor stations in Upton Countyreportedly used 29.7 rrillion gallons (91.1 acre-feet) ofground water from six wells in the county in 1965.

Other Industrial Uses

Other industrial uses of ground water includesuppl ies for: (1) drillin!j oil and gas wells, (2) washingdown equipment at gelS recycling plants, (3) sealingwooden tanks used to store crude oil, and (4) lease waterin oil fields. In 1965, approximately 16 million gallons(55 acre-feet) of ground water was used for thesepurposes, of which 85 percent or 13.6 million gallonswas from the Trinity Sand.

Irrigation

Irrigation of crop land in Upton County began in1956. During the nex t 8 years, the practice slowlydeveloped and by 1960, 13 wells were in operation.Irrigation accelerated du ring the 1960's and by 1965, 39wells were used to irrigate 2,440 acres in the county. Allthe wells were in the northeast quarter of the county,principally in the Midkiff area. An additional four wellsin Reagan County and one well in Midland were used toirrigate land in Upton County.

The irrigation wells, all tapping the Trinity Sand,range in depth from 2:30 to 395 feet; the yields rangefrom less than 100 gpm to a maximum of 350 gpm,most of the yields ranging between 100 and 150 gpm.

Water for irrigaticn is appl ied by sprinkler systemsor in furrows. Pre-planting irrigation, in which as muchas 9 inches of water per acre is applied during the winterand early spring month:;, is a common practice. In 1965an estimated 3,000 acre-feet of ground water waspumped for irrigation. This is about two-thirds of thetotal quantity of ground water pumped in UptonCounty for all purposes.

- 32-

Domestic and Livestock

Pumping of ground water for domestic and live­stock use is relatively small, amounting to only 84million gallons or 230,000 gpd in 1965. About 80 to 90percent of this amount was from the Trinity Sand; therest was obtained from the Triassic rocks and alluvium inthe southwestern part of the county where the TrinitySand is absent. Most of the domestic and livestock wellsare equipped with windmills, the yields of whichgenerally are less than 5 gpm; a few livestock anddomestic wells are equipped with small submergiblepumps.

Fluctuations of Water Levels

The fluctuations of water levels in wells dependupon various factors, the most important of which arethe discharges from wells and the natural recharge.

Long-term records of annual changes in waterlevels in Upton County are available in only two wells,YL-44-33-503 and YL-44-33-504. The hydrographs ofthese unused wells (F igure 13) show that during theperiod 1954-65, the water levels declined 2.4 and 2.1feet. The declines reflect pumping of ground water in anarea where development of irrigation has been on a smallscale-only six wells were used in 1965. The low (211feet) water level in well YL-44-33-503 in December1960 probably reflects pumping in this well and in anearby well. The decline in well YL-44-33-501, currentlyin use, was somewhat greater; since 1959, the leveldeclined slightly less than 10 feet. The larger decline inwell YL-44-33-501 probably can be attributed to thefact that the well not only is being used for irrigationbut is closer to the center of pumping than are the othertwo wells.

In the east-central part of the county, along theUpton-Reagan County line, water levels have declined asmuch as 25 feet since 1949, when pumping for gasolineplants began in this area.

In the M idk iff area, the principal area of irrigation,the water levels have declined as much as 30 feet since1937, of which nearly 23 feet occurred since 1952,when irrigation began.

The hydrograph (Figure 14) of well YL-44-49-301,in the Upton County well field near Rankin, showschanges in water levels related to nearly continuouspumping for mu nicipal supply and to recharge frominfiltration of storm runoff in Rankin Creek. From late1953 to mid-1964, water levels in well YL-44-49-301declined a maximum of about 34 feet. Water levels roseseveral feet folowing the heavy precipitation in Septem­ber 1964 and as much as 39 feet after the 6.8 inches ofrain in May 1965. However, the water levels againresumed their downward trend and by September 1966,the water level had declined a net 18 feet since 1953.

150

160

170

a~ / r--- ........-...1-- .... ...£l

'\,V '""'0~~~Well YL-44-33-501

Dept~ 340 IfeetI

--n n

~~~ \/Well YL-44-33-504

1\ f--

t----+---+--- D,epth ~30 fel(t I " \ 1/~ 160 0- Well YL~44:t50:--""1\ 1<~:-+:-¥-"",,--+--/--+---+--~o 170 ./

~ Depth 330 feet \ 1 ""o 180

190 \ 1200 I---+--+---+-----+-~\+---+-1--+-----+----___+____+______

\1210 ~----+---+------if----+'--+----1---vt--~--+---+---+---+---+---l

LIJo~ 150Q:::::>(/)

CIZ~ 160...J

~o...JLIJm 170~LIJLIJLI..

Z

1954 1955 1956

Figure 13

Hydrographs of Three Wells in the Trinity Sand

US. Geological Survey in cooperation with the Texas Water Development Board

and the Commissioners Court of Upton County

- 33 -

~ 400oa:Wa..en 300 f-------IZo...J

• ...Jw<l:~C)a.. u. 200~Oa.. en

oz<l:~ 100oII-

Z

PUMPAGE FROM UPTON COUNTY WELL FIELD

Approximate water levelin November, 1953

wU<l:u.a:::::> 3('~------------+----+-----\-----+--------------lenoZ<l:...J

~ 4('~------------+-----I-----+----+--------------1o...JWCD

I­W 50 r-----------.--+-----jf-------+--+--+----'l..--~------__lwu.

~

0;~ 60 t--------------+---+----------+-----+---+------I<l:~

oI-

~ 70t--------r-----t------------+----------__la..wo

HYDROGRAPH OF WELL YL- 44-49-301

enwIUZ

~

zoga..uwa:a..

5t------------.-t----

~ t---------

2

1964 1966

Figure 14

Hydrogroph of Well YL-44-49-301, Pumpage From Wells in the Upton County

Well Field, and Precipitation at Rankin, May 1964-September 1966

U. S Geological Survey in cooperation with the Texas Water Development Board

and the Commissioners Court of Upton County

- 34·

The rather large declines experienced in severalparts of the county are in accord with the generally lowpermeability of the Trinity Sand and the low specificcapacities of the wells tapping the Trinity. Records ofwater-level fluctuations in wells tapping the deeperformations, principally the Santa Rosa Sandstone, aretwo meager for comparative purposes.

Well Construction

Of the 622 wells inventoried in Upton County,only one was dug; the rest were drilled.

Most of the domestic and livestock wells that~ave been recently drilled in the county have smalldiameter casing, 5 to 6 inches, and are cased to thebottom of the well. The casings are either torch-slottedor perforated opposite the water-bearing sand. In theolder wells, it was (:ommon practice to set only a joint ofsurface casing-10 or 20 feet long-through the surficialdeposits, and the rest of the well was completed withoutcasing; this practic:e resulted in the loss of some wellsdue to cav ing.

Municipal, industrial, and irrigation wells are largerin diameter-8 to 20 inches-and are usually completedwith large-diameter surface casing which is cemented tothe wall of the well. Smaller-sized casing is set from thesurface to the bottom of the producing sand. Slotted orperforated casing is set opposite the sand and the spacebetween the perforated casing and the wall of the well isfilled with small-size gravel, pea-sized gravel being themost commonly used. The gravel increases the effectivediameter of the well and protects the casing from cavingof the sand.

Most wells of the type described above aredeveloped by pumping. However, those tapping the SanAndres Limestone commonly are acidized to increasethe permeability of the limestone. Some wells tappingthe Santa Rosa rave been sand fractured to createfissures, thereby increasing the yield. The use of explo­sives to increase the yield of the Trinity Sand has beenreported.

CHEMICAL QUALITYOF GROUND WATER

Precipitation, in the form of rain or snow, containsonly small amounts of mineral matter. Once the waterreaches the land surface, however, it dissolves mineralsubstances from the soil and rocks over and throughwhich it moves. Thus, all ground water naturallycontains dissolved minerals, the degree of mineralizationdetermining its suitability for municipal, irrigation, andindustrial uses. Contamination or pollution by variousmeans may change the character of a water. Organicmaterials are common polluting agents. However, pollu­tion may result from mixing with highly mineralized

- 35-

water; such may be the case in some areas where highlymineralized water produced with oil is placed in earthernpits.

During the investigation in Upton County, 178samples of water from wells and earthen pits werecollected and, except where noted, the samples wereanalyzed by the Texas State Department of Health. Thelocations of all the wells sampled are shown in Figure19. The resu Its of the analyses are shown in Table 6included with analyses of water obtained during previousinvestigations. The concentrations of the chemical con­stituents in the water (Table 6) are expressed in ppm(parts per million) which is the unit weight of asubstance in a million unit weights of water. However, itis frequently more convenient for interpretive purposesto compare water in terms of equivalents per million,which is a measure of the reactive weights of thedifferent constituents. The concentration of an ion inequivalents per million is determined by multiplying itsconcentration in parts per million by the reciprocal ofthe combining weight of the appropriate ions. Thechemical character of samples of water from the aquifersunderlying Upton County is illustrated in Figure 15 interms of the percentage equivalents per million (reactingvalues) Of the anions and cations in solution. The threeprincipal cations-calcium, magnesium, and sodium(includes potassium) are shown in the left half of thecircle, being separated from the three principal anions­bicarbonate, sulfate, and chloride (includes nitrate andfluoride) by a vertical line. To make the illustrationmore easily understood, that part of the diagramshowing the magnesium and sulfate was made solid. Thesource and significance of the dissolved-mineral constit­uents and properties of water in Upton County summa­rized in Table 3 was adapted from Doll and others(1963, Table 7).

Most state and municipal authorities have adoptedthe standards set by the U.S. Public Health Service(1962, p. 7-8) for drinking water used on commoncarriers in interstate commerce. The standards aredesigned to protect the traveling public and are useful inevaluating public-water supplies, although they may notbe directly applicable in an area such as Upton Countywhere much of the water may exceed the standards forsome constituents. According to the standards, in apublic water supply the chemical constituents shouldnot be present in excess of the concentrations shownbelow except where more suitable supplies are notavailable.

Table 3.--Source and Significance of Dissolved-Mineral Constituents and Properties of Water

(F rom Doll and Others, 1963, Table 7)

CONSTITUENTOR

PROPERTY

Iron (Fe)

Calcium (Ca) andmagnesium (Mg)

Sodium (Na) andpotassium (K)

Bicarbonate (HC03)and carbonate (C03)

Chloride (CII

Fluoride (F)

Dissolved solids

Hardness as CaC03

Specific conductance(micromhos at 250 C)

Hydrogen ionconcentration (pH)

SOU RCE OR CAUSE

Dissolved from practically allrocks and soils, commonly lessthan 30 ppm. High concentra­tions, as much as 100 ppm, gener­ally occur in highly alkalinewaters.

Dissolved from practically allrocks and soils. May also bederived from iron pipes, pumps,and other equipment. More than1 or 2 ppm of iron in surfacewaters generally indicate acidwastes from mine drainage orother sources.

Dissolved from practically all soilsand rocks, but especially fromlimestone, dolomite, and gypsum.Calcium and magnesium arefound in large quantities in somebrines. Magnesium is present inlarge quantities in sea water.

Dissolved from practically allrocks and soils. Found also inancient brines, sea water, indus­trial brines, and sewage.

Action of carbon dioxide in wateron carbonate rocks such as lime­stone and dolomite.

Dissolved from rocks and soilscontaining gypsum, iron sulfides,and other sulfur compounds.Commonly present in mine watersand in some industrial wastes.

Dissolved from rocks and soils.Present in sewage and found inlarge amounts in ancient brines,sea water, and industrial brines.

Dissolved in small to minutequantities from most rocks andsoils. Added to many waters byfluoridation of municipal sup­plies.

Decaying organic matter, sewage,fertilizers, and nitrates in soil.

Chiefly mineral constituents dis­solved from rocks and soils.Includes some water of crystalli­zation.

I n most waters nearly all thehardness is due to calcium andmagnesium. All the metalliccations other than the alkalimetals also cause hardness.

Mineral content of the water.

Acids, acid-generating salts, andfree carbon dioxide lower the pH.Carbonates, bicarbonates, hydrox­ides, and phosphates, silicates,and borates raise the pH.

- 36-

SIGNIFICANCE

Forms hard scale in pipes and boilers. Carried over in steam ofhigh pressure boilers to form deposits on blades of turbines.I nhibits deterioration of zeol ite-type water softeners.

On exposure to air, iron in ground water oxidizes to reddish­brown precipitate. More than about 0.3 ppm stain laundry andutensils reddish-brown. Objectionable for food processing, tex­tile processing, beverages, ice manufacture, brewing, and otherprocesses. U.S. Public Health Service (1962) drinking-waterstandards state that iron should not exceed 0.3 ppm. Largerquantities cause unpleasant taste and favor growth of ironbacteria.

Cause most of the hardness and scale-forming properties ofwater; soap consuming (see hardness). Waters low in calcium andmagnesium desired in electroplating, tanning, dyeing, and intextile manufacturing.

Large amounts, in combination with chloride, give a salty taste.Moderate quantities have I ittle effect on the useful ness of waterfor most purposes. Sodium salts may cause foaming in steamboilers and a high sodium content may limit the use of water forirrigation.

Bicarbonate and carbonate produce alkalinity. Bicarbonates ofcalcium and magnesium decompose in steam boilers and hotwater facilities to form scale and release corrosive carbon diox idegas. In combination with calcium and magnesium, cause carbon­ate hardness.

Sulfate in water containing calcium forms hard scale in steamboilers. In large amounts, sulfate in combination with other ionsgives bitter taste to water. Some calcium sulfate is consideredbeneficial in the brewing process. U.S. Public Health Service(1962) drinking-water standards recommend that the sulfatecontent should not exceed 250 ppm.

In large amounts in combination with sodium, gives salty taste todrinking water. In large quantities, increases the corrosiveness ofwater. U.S. Pu blic Health Service (1962) drinking-water stan­dards recommend that the chloride content should not exceed250 ppm.

Fluoride in drinking water reduces the incidence of tooth decaywhen the water is consumed during the period of enamelcalcification. However, it may cause mottling of the teeth,depending on the concentration of fluoride, the age of the child,amount of drinking water consumed, and susceptbility of theindividual. (Maier, 1950)

Concentration much greater than the local average may suggestpollution, U.S. Public Health Service (1962) drinking-waterstandards suggest a limit of 45 ppm. Waters of high nitratecontent have been reported to be the cause of methemoglo­binemia (an often fatal disease in infants) and therefore shou Idnot be used in infant feeding. Nitrate has been shown to behelpful in reducing inter-crystalline cracking of boiler steel. Itencourages growth of algae and other organisms which produceundesirable tastes and odors.

U.S. Public Health Service (1962) drinking-water standardsrecommend that waters containing more than 500 ppm dissolvedsol ids not be used if other less mineralized supplies are available.Waters containing more than 1000 ppm dissolved solids areunsuitable for many purposes.

Consumes soap before a lather will form. Deposits soap curd onbathtubs. Hard water forms scale in boilers, water heaters, andpipes. Hardness equivalent to the bicarbonate and carbonate iscalled carbonate hardness. Any hardness in excess of this iscalled non-carbonate hardness. Waters of hardness as much as 60ppm are considered soft; 61-120 ppm, moderately hard; 121 -180ppm, hard; more than 180 ppm, very hard.

Indicates degree of mineralization. Specific conductance is ameasure of the capacity of the water to conduct an electriccurrent. Varies with concentration and degree of ionization ofthe constituents.

A pH of 7.0 indicates neutrality of a solution. Values higher than7.0 denote increasing alkalinity; values lower than 7.0 indicateincreasing acidity. pH is a measure of the activity of thehydrogen ions. Corrosiveness of water generally increases withdecreasing pH. However, excessively alkaline waters may alsoattack metals.

SUBSTANCE CONCENTRATION(PPM)

Chloride (CI) 250

Fluoride (F) 1.0*

Iron (Fe) .3

Nitrate (N03) 45

Sulfate (S04) 250

Dissol\led solids 500

* Based on the average of maximum daily air tempera­ture of 77°F at Midland, Texas, for the period1931-60.

Chemical reqlJ irements for industrial uses of watervary accord ing to the industry, but they are fairly rigidwhere water is used in food, paper, or some chemical­process industries. The most common industrial uses ofwater in Upton COlJ nty are for cooling, boiler feed, andwaterflooding of oil reservoirs. Excessive concentrationsof dissolved solids are a problem in water used forcooling because they tend to accelerate corrosion (Cali­fornia State Water Pollution Control Board, 1963, p.182). The use of water for boiler feed is dependent onvery strict limits relative to the dissolved-solids contentand silica because of the formation of scale in theboilers. High-pressure systems, operating at a pressureof more than 400 psi (pounds per square inch), requirea dissolved-solids content of 50 ppm or less and a silicacontent of not mon:! than 1 ppm; low-pressure systems,less than 150 psi, c(ln use water hav ing as much as 3,000ppm dissolved solid,) and 40 ppm silica (Moore, 1940, p.263).

According to the U.S. Salinity Laboratory Staff(1954, p. 69-82), some of the principal factors thatdetermine the quality of water for irrigation are theconcentrations of dissolved solids, sodium, and boron.The relative importance of the dissolved constituents inirrigation water is dependent upon the degree to whichthey accumulate in the soil. Sodium is a significantfactor in evaluating irrigation water because a high SAR(sodium-adsorption ratio) may cause the soil structure tobreak down. The BSC (residual sodium carbonate) isanother factor used in assessing the quality of water forirrigation. According to Wilcox (1955, p. 11) watercontaining more than 2.5 epm (equivalents per million)RSC is not su itabl ~ for irrigation, 1.25 to 2.5 epm ismarginal, and less than 1.25 epm probably is safe.Residual sodium c:!rbonate values are not shown inTable 6 because all ~;amples contained 0 epm.

Of the water samples analyzed, 143 were from theTrinity Sand, 29 from the Santa Rosa Sandstone andChinle Formation equivalent of Triassic age, 12 from thealluvium, and 1 fron, the Fredericksburg Group of rocks.Some of the samples collected represent a mixture ofwater from more than one aquifer. No analyses weremade of water from the Permian rocks, except forsamples of water produced with oil (Table 7). Allavailable data indicate that' the water in the Permian

- 39-

rocks is highly mineralized and would be unsuitable foruse except in waterflood operations.

Although parts of Upton County now yieldground water that has been contaminated, presumablyby the disposal of oil-field brines, it is desirable first tosummarize the chemical character of the ground water inthe various formations where it has not been contami­nated. This affords a basis for comparison of the nativewaters, those whose chemical character is natural to aparticular water-bearing zone and locality.

Trinity Sand

Characteristically, water from the Trinity Sand,the principal aquifer in the county, is high in sulfate,dissolved-solids, and fluoride content and is very hard. Ingeneral, the water is of the calcium magnesium sulfatetype, in which calcium and magnesium, expressed inchemical equivalents, are first and second in order ofabu ndance among the cations but neither amou nts to 50percent of all the cations. Su Ifate is the predominantanion, generally exceeding 50 percent of the totalanions. Of the 143 water samples from wells known tobe screened in the Trinity Sand, only 8 contained lessthan 250 ppm of sulfate, and two-thirds of the samplescontained more than 500 ppm.

The dissolved-solids content, which influences orlimits the general use of ground water, ranged over widelimits (283 to 8,420 ppm), although the higher concen­tration is probably the result of contamination. Nearlythree-fourths of the samples exceeded 1,000 ppm. Thewells that yield fresh (less than 1,000 ppm dissolvedsolids) water are not confined to anyone part of thecounty but are widely scattered throughout the aquifers(F igure 15). In general, however, much of the freshwater is from wells along Concho Bluff and the northedge of the county where the Trinity Sand underlies thesurface at fairly shallow depths and conditions are morefavorable for recharge (F igures 15 to 18).

Fluoride is a problem in the water from theTrinity Sand in Upton County. Most of the samplescontained more than 1.0 ppm fluoride; the average wasabout 2.7 ppm.

The hardness of water is most commonly recog­nized by its effect upon soap consumption. Calcium andmagnesium-primarily as salts of sulfate-cause nearly allthe hardness in the water from the Trinity Sand. Of thesamples tested, none contained less than 180 ppmhardness, which is the lower limit of water classified asvery hard.

The water from the Trinity Sand does not meetthe chemical standards established by the U.S. PublicHealth Service for drinking water used on commoncarriers engaged in interstate commerce. Nevertheless,

this aquifer furnishes the municipal water for Rankinand most of the water for domestic use, the water fromthe other aqu ifers being either more mineralized or inquantities too small for use.

The water from the Trinity Sand is used exten­sively for industrial purposes. However, the water isusually treated to reduce the hardness. Nearly all thecompressor and gasol ine plants use zeol ite exchangecolumns for this purpose. The columns are rechargedperiodically by flushin;} with sodium chloride brine. Thesilica content of the water from the Trinity generally isnot a problem except when used in boilers. The presenttrend is toward closed cooling systems in which thewater is chemically treated to prevent corrosion andformation of scale. I n the closed systems, the water isrecycled which result; in a considerable reduction inwater consumption and pumping costs.

Water from the Trinity Sand has been used forirrigation successfully for several years. The chemicalquality data show that the sod ium-adsorption ratio(SA R) is fairlY' low, glmerally less than 5. According tothe U.S. Salinity Laboratory Staff (1954, p. 80), theuncontaminated water in the Trinity Sand is classed ashigh to very high in salinity hazard (based on the specificconductance in micrornhos per centimeter at 25()C) andis low to medium in sodium hazard. Generally, waterhaving high to very high salinity hazard should be usedon well drained soils, and the crops should be very salttolerant. The calcareolJs character of the soils in UptonCounty tends to reduce the effect of the sodium hazard.

Santa Rosa Sandstone

Samples of water were collected for chemicalanalysis from 14 wells, of wh ich 12 are known to bescreened in the Santa Rosa Sandstone and 2 presumablytap the aquifer (Table 6 and Figure 15). Most of thewells are in the southwest corner of the county wherethe depth to the top of Santa Rosa is less than 25 feet inmany places.

In general, the water in the Santa Rosa is morehighly mineralized th.:m that in the Trinity Sand, thedissolved-solids content of the water ranging from 1,260ppm in well YL-45-54-902 (160 feet deep) to 15,000ppm in well YL-44-2(j-103 (1,100 feet deep). The leastmineralized water is from wells in the southwestern partof the county. In this area, the Santa Rosa yields watercontaining as much as 4,800 ppm dissolved solids, 2,100ppm sulfate, and 1,230 ppm chloride. I n most of thewells, the sulfate content greatly exceeds the chloridecontent. Wells scree led in the Santa Rosa in thenorthern and northea~,tern parts of the county are morethan 600 feet deep and yield moderately to very salinewater, in which the chloride content is considerably inl~xcess of the su Ifate.

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The high sulfate, hardness, and dissolved-solidscontent preclude the use of water from the Santa Rosafor public or domestic supplies. At present (1966) theprincipal use of the water is for livestock watering,although until recently some of the water was used forwaterflooding. Because of the low specific capacities andconcomitant high pumping lifts, however, use of theSanta Rosa as a source of water for waterflooding wasdiscontinued.

Other Aquifers

Few water samples were obtained from wellstapping the other aqu ifers, the San Andres Limestone,Chinle Formation equivalent, Fredericksburg Group, andalluvial deposits.

One water sample was collected from a wellta pping the San Andres Limestone. The well,YL-45-23-902, drilled as an oil test and later convertedto a water well, yielded brine that had a low pH (5.3)and a high hydrogen sulfide (335 ppm) content. Use ofthe well was discontinued in 1964.

Samples of water were obtained from four wells inthe Chinle Formation equivalent (Table 6). The waterfrom three of the wells was high in sulfate and fluoride,and was slightly saline; water from the fourth well wasalso high in sulfate and fluoride but contained only 790ppm dissolved solids.

Only one well (YL-44-42-901) in the county isknown to be supplied from the Fredericksburg Group.The water from this well was fresh-less than 1,000 ppmdissolved solids-, low in sulfate (166 ppm) and chloride(112 ppm), but very hard (378 ppm). Except for theexcessive fluoride content (2.6 ppm), the water issuitable for drinking. Water in this well is perched abovethe main aquifer-the Trinity Sand-and during extendedperiods of drought, the well reportedly goes dry.

The chemical quality of the water from thealluvium is similar to that from the Trinity Sand, withwhich it is in hydraulic continuity. Water from six wellsin the alluvium was slightly saline, high in sulfate andfluoride, and very hard. Although the wells tapping thealluv ium are shallow, 36 to 118 feet deep, the nitratecontent-commonly high in shallow wells-was less than44 ppm (the recommended limit) except in one well(YL-45-39-401) which contained 157 ppm of nitrate.The nitrate in this well was probably derived fromorganic wastes from a nearby stock yard. Because of thehigh sulfate content, the water in the alluvium is notsuitable for drinking purposes, but it is used for livestockwatering.

In summary, the Trinity Sand yields water thatcommonly exceeds the limits for drinking water sug­gested by the U.S. Public Health Service in at leastseveral constituents-the dissolved-solids, sulfate, and

fluoride content. However, because water of betterquality is not readily available, the Trinity Sand is theprincipal source of water for public and domesticsupplies.

GROUND-WATER PROBLEMS

Contamination from Disposalof Oil-Field Brines

The public clnd domestic water supplies of UptonCounty are dependent entirely on the ground-waterresources of the county and adjacent areas. The presentpractice of disposing of oil-field brine through unlinedearthen pits is a potential hazard to the chemical qualityof the ground-watE!r supplies in the county.

Brine placed in unlined surface pits either evapo­rates or seeps into the ground, eventually percolatingdownward to the water table in a manner similar to thatof precipitation an the land surface. Although theaverage yearly potential evaporation rate from a free­water surface in Upton County is slightly less than 7feet, it cannot be depended upon to dispose of the largequantities of brinE! continuously being produced. Actu­ally, the evaporation rate of the brine is considerably lessthan that of fresh water because of the presence of an oilfilm on the brine in most of the pits. Furthermore, theevaporation dispo~,es of the water but leaves the salt inthe pits as a potent ial contaminant.

The records of the Texas Water Commission andTexas Water Po lIution Contro I Board (1963, p. 233)show that 18%-million barrels (766.5 million gallons orabout 2,352 acre-f,~et) of brine reportedly was producedin Upton County in 1961. Of this amount nearly11 ~-million barrel!; (483 million gallons or about 1,482acre-feet), or about 63 percent of the total, was disposedof through unlined surface pits. The rest of the brine wasdisposed of throuqh injection wells (nearly 6%-millionbarrels or 37 per:ent of the total) or by unknownmethods. The repo'ted amounts of brine production andamounts and met10ds of brine disposal are listed inTable 4 by oil fields and by the 20 brine-producing areasshown on Figure 1n.

Figure 16 shows the areas of brine production anddisposal in 1961. The figure also shows the chloride andsulfate concentrations in water samples from wellstapping the Quater1ary alluvium, Fredericksburg Group,Trinity Sand, and ":he Chinle Formation equivalent andSanta Rosa Sandstone where the latter two formationsoccur at shallow jepths. The natural water in theseaquifers is characterized by a low chloride-sulfateratio less than 0.5 in all but 14 samples. However, sixsamples had chloride-sulfate ratios of 1 or greater andwere presumably contaminated by brine that was dis­posed of in nearby surface pits. Four of the six samples

- 41 -

had chloride concentrations that exceeded 3,000 ppmwhich indicates that a considerable degree of contami­nation has occurred. The four samples were from wellslocated in the McCamey oil field (area 11) whichproduced 11 million barrels of brine in 1961 or 60percent of the total amount produced in the county inthat year. Of the 11 million barrels produced in thefield, 6%-million barrels was disposed of through unlinedsurface pits.

Water from well YL-44-26-513 in area 2 alsoshowed strong evidence of contamination (F igure 16).The well, 312 feet deep, is 100 feet southeast ofabandoned salt-water disposal pits. Figure 17 shows therelationship between pumping and the chemical qualtiyof the water from the well. The first sample, collected inJune 1963 after the well had pumped an estimated54,000 gallons of water, contained 11,200 ppm chlorideand 940 ppm sulfate. By March I, 1964, after pumpingmore or less continuously for 8 months, the chloridecontent had decreased to 1,070 ppm; during this sameperiod the sulfate content remained almost unchanged.Two water samples collected during the next two years,when the well was operated only intermittently, showeda slight increase in chloride content-1,280 and 1,760ppm, respectively; whereas, the su Ifate contentdecreased to 790 ppm. These data indicate that after along period of continuous pumping, a substantial part ofthe contaminant within the radius of influence of thewell had been pumped from the aquifer and that afterpumping had stopped, the chloride content began toincrease slowly.

At least one other well in area 2 probably has beencontaminated (the water contained 900 ppm chlorideand 900 ppm sulfate) and three wells that yield watercontaining normal concentrations of sulfate but unusu­ally high concentrations of chloride may be contami­nated.

I n general, Figure 16 shows that a marked degra­dation in the chemical quality of the ground waterapparently has not occurred except locally. It is possiblethat contamination may be more extensive than isindicated by Figure 16 because of the low velocity ofmovement of the ground water. Brine that is placed in apit may not affect the chemical qualtiy of the water inwells nearby for many years. Moreover, in some areas ofsurface-disposal pits, wells either are not available, or ifavailable, were not sampled.

Recently, a statewide "no-pit" order was issued bythe Railroad Commission of Texas to become effectiveJanuary 1, 1969. As a result of this order and theexpansion of secondary recovery operations in thecounty, most of the brine is now being injected intowells.

Table 4,--Reported Brine Production and Disposal in 1961, Upton County

AREA DISPOSAL IN DISPOSAL IN TOTAL BRINESHOWN ON FIELD SURFACE PITS INJECTION WE LLS PRODUCTIONFIGURE 16 (BBL) (BBL) (BBL)

Pegasus/Devonian/ 0 0 0

Pegasus/E Ilenbu rger/ 0 238,463 238,463

Pegasus/Pennsylvanian/ 0 396,816 396,816

Pe'gasus/Spraberry / 37,958 0 37,958

Pe'gasus/Wolfeamp/ 0 0 0

Total 37,958 635,279 673,237

2 Bllnedum 506,455 186,400 692,855

B1medum/Spraberry / 685,544 9,855 695,399

N aal Ranch 0 0 0

Spraberry/Trend areal 1,603,497 231,975 1,874,107-

Spraberry/Trend area, Clearfork/ 35,486 0 35,486

Total 2,830,982 428,230 3,297,847 -

3 A:lame/Bend/ 0 0 0

A:lame/Devonian/ 43,095 0 43,095

Adame/E lIenburger/ 1,345 0 1,345

Adame/Silurian/ 0 0 0

Adame/Wolfeamp/ 0 0 0

Jigger- Y /Pennsylvanian/ 359 0 359

McElroy 309,998 0 309,998

M iether/Grayburg/ 4,230 0 4,230

Texel/Devonian/ 720 0 720

Texel/Ellenbu rger/ 78,041 0 78,041

Texel/Pennsylvan ian/ 2,358 0 2,358

Total 440,146 0 440,146

4 Davis 7,576 0 7,576

Davis/Ellenbu rger/ 17,009 0 17,009

Davis/Pennsylvanian/ 200 0 200

Cavis/Wolfeamp-oil/ 0 0 0

Total 24,785 0 24,785

5 Wilshire 0 0 0

Wilshire/E lIenbu rger/ 801,461 0 801,461

Wilshire/Pennsylvanian/ 0 0 0

Total 801,461 0 801,461

6 Hazel/Spraberry/ 4,252 0 4,252

Total 4,252 0 4,252

See footnote at end of table.

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Table 4.--Reported Brine Production and Disposal in 1961, Upton County--Continued

AREA DISPOSAL IN DISPOSAL IN TOTAL BRINESHOWN ON FIELD SURFACE PITS INJECTION WELLS PRODUCTIONFIGURE 16 (BBL) (BBL) (BBL)

7 Amacker-Tippett 2,435 0 2,435

Amacker-Tippett/Detrital/ 0 0 0

Amacker-Tippett/Ellenburger/ 83,235 0 83,235

Amacker-Tippett/Fusselman/ 1,931 0 1,931

Amacker- Tippett/Strawn/ 2,360 1,460 3,820

Amacker-Tippett/Strawn-A·/ 150 0 150

Amacker- Tippett/Wolfcamp/ 658 0 658

Amacker-Tippett, E. 540 0 540

Amacker-Tippett, S. 0 0 0

Amacker-Tippett, S./Detrital/ 0 0 0

Amacker-Tippett, S./8750 Strawn/ 0 0 0

Amacker-Tippett, S./Wolfcamp/ 17,225 0 17,225

Jack Herbert 6,037 0 6,037

Jack Herbert/Devonian/ 9,630 0 9,630

Total 124,201 1,460 125,661

8 Will rode/Cisco/ 0 0 0

Willrode/Leonard Lime/ 0 0 0

Willrode/Strawn/ 365 0 365

Total 365 0 365

9 Heluma/Devonian/ 0 0 0

Heluma/E Ilenbu rger/ 11,550 27,061 38,611

Heluma/Pennsylvanian/ 0 0 0

Total 11,550 27,061 38,611

10 Fradean/Ellenburger/ 2,368 0 2,368

F radean/Strawn/ 6,219 0 6,219

King Mountain 0 0 0

King Mountain/Devonian/ 30,222 0 30,222

King Mountain/Ellenburger/ 208,939 0 20B,939

King Mountain/Fusselman/ 18,252 0 18,252

Total 266,000 0 266,000

11 McCamey 6,522,598 4,538,990 11,061,588

McCamey/Ellenburger/ 13,730 0 13,730

Shirk/Grayburg/ 22,147 0 22,147

Total 6,558,475 4,538,990 11,097,465

See footnote at end cf table.

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Table L..-- Reported Brine Production and Disposal in 1961, Upton County--Continued

AREA DISPOSAL IN DISPOSAL IN TOTAL BRINESHOWN ON FIELD SURFACE PITS INJECTION WELLS PRODUCTIONFIGURE 16 (BBL) (BBL) (BBL)

12 Crossett, N/Clearfork UP.! 38,723 0 38,723

Crossett, S.!Devonian/ 12,951 0 12,951

Total 51,674 0 51,674

13 Webb Ray 9,000 0 9,000

Total 9,000 0 9,000

14 Hurdle 3,766 0 3,766

Hurdle/Queen/ 0 0 0

Total 3,766 0 3,766

15 Rodman-Noel/Grayburg/ 0 1,000,000 1,000,000

Flodman-Noel/San Andres/ 0 100,000 100,000

Total 0 1,100,000 1,100,000

16 Crockett 139,977 0 139,977

Total 139,977 0 139,977

17 Corbett/Ellenburger/ 73,000 0 73,000

Total 73,000 0 73,000

18 Blue Danu be/E lIenbu rger/ 1,400 0 1,400

Blue Danube/Strawn/ 0 0 0

Total 1,400 0 1,400

19 Flat Rock/E lIenbu rger/ 45,720 0 45,720

Flat Rock/Spraberry/ 25,039 0 25,039

Total 70,759 0 70,759

20 Block 4/Devonian/ 2,370 0 2,370

Block 4/Wolfcamp/ 31,000 0 31,000

Block 4/Pennsylvanian/ 0 0 0

Total 33,370 0 33,377

1 to 20 County total 11,483,121 6,731,020 18,252,776 •

• Includes 38,635 barrels disposed of by methods other than surface pits and injection wells.

- 44-

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( A bandoned salt-water --

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\YL-44-26-513

!- Depth: 312 feet -S lotted interval:

212 -312 feet

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- Location map -

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~Accumulative discharge

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SUlfate~ \ _l-I-- -

I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I

1963 1964 1965

8000

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6000

4000

2000

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Figure 17

Relation of Chloride and Sulfate Concentrations

to Discharge of Well YL-44-26-513

US Geologicol Survey in cooperation with the Texas Water Development Boord

and the Commissioners Court of Upton County

Contamination fromImproperly Cased Wells

Improperly or inadequately cased oil or gas wellsare also potential sources of contamination of theground-water supplies. The Oil and Gas Division of theRailroad Commission I)f Texas is responsible for seeingthat oil and gas wells are properly constructed, and theTexas Water Development Board furnishes ground-waterdata to oil operators and to the Railroad Commission inorder that all fresh water may be protected. The term"fresh water" is considered by the Surface CasingProgram of the Texas Water Development Board toinclude water of usabe qualtiy. The term "usable" initself is rather indefinite in that the qualitative limitsdiffer from place to place in the State. In Upton County,the term "water of wable quality" denotes water thatmay be of satisfactory quality for domestic, livestock,irrigation, or public supply purposes or for somerestricted industrial purposes. Thus, "water of usablequality" in Upton Cou lty may contain as much as 5,000ppm dissolved solids.

The Railroad Commission requires that stratacontaining usable watt~r be protected by surface casingof new or recond itioned pipe and cement, or byalternate protection devices. The amount of protectionrequired in the countV differs from place to place, but~Ienerally casing and cement is required to a depth of afew tens of feet belclw the base of the Trinitv Sand.However, most of tle older oil fields such as theMcCamey field do not have rules pertaining to surface­casing requirements. As a consequence, many of thewells have been inadequately cased, improperlycemented, or, in some of the abandoned wells, the casingwas removed.

One of the larqer oil fields in the county, themultiple county Spraberry-Trend Area field (in area 2,Figure 16) has field rules requiring a minimum of 120feet of surface casing. Inasmuch as the base of theTrinity Sand ranges f'om about 270 to 320 feet belowthe surface in that clrea, the minimum surface-casingrequirement is deficiE!nt by as much as 200 feet. Ofprincipal concern is the fact that some of the oil wells inthis area have been converted to injection wells forsecondary recovery of oil. Injection of oil-field brinesinto wells for purpoSl~s of either secondary recovery orfor brine disposal is a potential source of contaminationof grou nd water in thi; field and in the older fields in thecounty in which some of the wells may be inadE~quately

cased.

Declines of Water Levelsand Well Yields

The problem of declining water levels and decreas­ing yields is becoming annually more serious in severalareas in Upton County. At present, the ama mostaffected is the Upton County well field (see hyclrograph

- 48-

of well YL-44-49-301, Figure 14), which supplies a largepart of the water needs of Rankin.

In this area, and to a lesser extent in the Midkiffarea and in an area near the east-central edge of thecounty, wells are closely spaced. As a result, the watertable has been lowered excessively, particularly duringthe summer months when water needs are the greatest,and the well yields have declined substantiallY. Gener­ally, the wells in these areas fully penetrate the aqu iferand the pumps are at or near the bottoms of the wells;hence, the yields cannot be increased. In fact, the yieldsand the water table can be expected to continue todecline, assuming, of course, that there is no decrease inpumping. These effects can be modified somewhat byadequate well spacing or well-field spacing.

AVAILABILITY OF GROUND WATER

Although ground water is considered as a renew­able resource, the rate at which it is renewed in UptonCounty is so slow as to preclude its consideration indetermining the quantity that would be perenniallyavailable for use.

In Upton County, pumpage in 1965 (about 3,600acre-feet) from the Trinity Sand, the principal aqu ifer,was at least three times the quantity that the aqu iferconceivably could transmit into the report area at thepresent hydraulic gradient-about 10 feet per mile.Consequently, most of the water is being removed fromstorage-in other words, the aquifer is being "mined."However, the aquifer contains a substantial quantity ofwater in transient storage. 0 n the basis of an averagesaturated thickness of 115 feet and a specific yield of 10percent, about 8 million acre-feet of water is available towells. The average coefficient of transmissibility of theTrinity Sand is low, probably not more than 2,500 gpdper foot. As a result, development of a substantial partof the water in storage probably is not economicallyfeasible because it would require a large number ofwidely spaced low-yield wells. I n addition, part of thewater in storage is not suitable for all purposes. In somelocalized areas of the county, particularly the easternpart, the water in the Trinity Sand is too highlymineralized for drinking.

Data are not sufficient to evaluate quantitativelythe potential development of the Santa Rosa Sandstone.Because of the generally poor chemical quality of thewater in the Santa Rosa and the low yields and specificcapacities of the few wells that tap the aquifer, verylittle additional development is anticipated.

The alluvial deposits presently furnish only smallquantities of water for livestock and rural domestic use.Additional development is possible in those parts of thecounty where the alluvium is thick and the potential forrecharge is good. Such an area is in F ivemile CreekValley near the Upton-Crockett County line where the

alluvium has a saturated thickness of as much as 150feet. The quality and quantity of the water in the areaprobably is satisfactory for irrigation. However, duringextended droughts, the yields of wells in the alluviummay be substantiallv reduced.

Data are not available to determine the water­supply potential of other water-bearing formations suchas the Grayburg Formation and the San Andres Lime­stone. At present, moderate quantities of very saline tobrine water is bein£1 pumped from wells tapping the SanAndres in the Midland Basin, and small quantities ofmoderately to very saline water associated with oil arebeing produced from wells in the Grayburg Formationon the Central Basin Platform. Additional quantities ofwater suitable for secondary recovery of oil probablycan be obtained from non-oil-bearing zones in theseunits throughout the county.

Figure 18 shows areas in Upton County favorablefor future development of ground-water supplies, princi­pally from the Trir ity Sand but also from the alluvium.The relative degrE'es of favorabil ity-mostfavorable,favorable, less favorable, and least favorable--are basedon the yields of wells presently being used, the thicknessof the aquifer, the estimated transmissibility of thewater-bearing section, and the observed specific capaci­ties of wells in USE~. The chemical quality of the waterwas not a criterion in determining areas of favorability.

The term IfclVorable" as used in this report doesnot imply that add ,tional water suppl ies can be obtai nedfrom the Trinity Sand without depleting the aquifer. Onthe contrary, any additional pumping from the Trinityin any part of the:ounty will only lead to accelerationof the rate of depletion because, as already mentioned,pumping in 1965 eJ(ceeded the probable rate of rechargeto i:he Trinity San:t. Nevertheless, the map is useful indesignating areas wherein additional supplies can beobtained.

The map shews that the most favorable area fordevelopment is in the northeast quarter of the countywhere relatively large-scale development already hasoccurred. Properly drilled and completed wells in thisarea can be expected to yield more than 100 gpm. Theleast favorable is in the southwest quarter of the countywhere the aquifer (Trinity Sand) is thin or absent. Yieldsof wells in this area would be small, probably less than25 gpm. The finger-shaped area in the southern part ofthe county probably is favorable for the development ofadditional groundwater supplies. In this area, thealluvium along Fivf~mile Creek is the principal source ofwater suitable for domestic supply and livestock.

- 49-

CONCLUSIONS

The ground-water resources of Upton County areinsufficient to furnish all the water needs of cities,industries, irrigation, and livestock. Consequently, asubstantial part of these needs have been met by theimportation of ground water from adjoining counties.The Trinity Sand, the principal source of water forpublic supply, irrigation, and domestic and livestockneeds, in 1965 supplied water somewhat in excess of theestimated annual recharge to the aqu ifer. Further devel­opment, which is anticipated, can only result in anacceleration of the rate of water-level decline and aconcomitant decrease in yields. Insofar as possible, anynew large-scale development should not be located nearpresent areas of concentrated withdrawals. Furthermore,because of the low rate at which the Trinity transmitswater, wider spacing of wells and smaller yields shouldbe considered.

Chemical analyses of water samples collectedduring this and previous investigations show that few ofthe wells in the Trinity Sand yield water that meets thestandards recommended for public supplies by the U.S.Public Health Service, the sulfate, fluoride, anddissolved-solids concentrations being the principal con­stituents that affect the quality of the water. Because noother sources of water are presently avai lable, thequality of the present supply should be protected.

The present study yielded evidence that some ofthe wells have been contaminated, presumably from thedisposal of oil-field brines into unlined surface pits. Evenif these sources of contamination were eliminated, it isexpected that contamination would continue for a longtime. A program of periodic resampling of water fromkey wells is recommended to trace changes in the extentand intensity of contamination; for most of the wells sosampled, a determination of chloride should be suffi­cient.

A network of six observation wells has beenestablished in Upton County, and water levels in thesewells are measured and recorded at least annually by theTexas Water Development Board. As development,particularly of the Trinity Sand, continues, additionalobservation wells shou Id be measured in areas wherepresent coverage is sparse or lacking.

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Baldwin, H. L., and McGuinness, C. L., 1963, A primeron ground water: Washington, U.S. Govt. Printingoffice, 26 p.

Broadhurst, W. L., Sundstrom, R. W., and Weaver, D. E.,1951, Public water supplies in western Texas: U.S.Geol. Survey Water-Supply Paper 1106, 168 p.

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California State Water Pollution Control Board, 1963,Water-quality criteria: California State Water Pollu­tion Control Board Pub. 3A, 548 p.

Cooper, H. H., and Jacob, C. E., 1946, A generalizedgraphic methoc for evaluating formation constantsand summarizing well-field history: Am. Geophys.Union Trans., v. 27, no. 4, p. 526-534.

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Doll, W. L., and others, 1963, Water resources of WestVirginia: West Virginia Dept. Nat. Resources, Div.Water Resources, 134 p.

Eargle, H. D., 195G, Some uranium occurrences in westTexas: Univ. THxas, Bur. Econ. Geology, Rept. Inv.27, p. 5-12.

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Kane, J. W., 1967, Monthly reservoir evaporation ratesfor Texas, 1940-1965: Texas Water Devel. BoardRept. 64, 111 p.

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Knowles, D. B., 1952, Ground-water resources of EctorCounty, Texas: Texas Board Water Engineers Bull.5210, 112 p.

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Meinzer, O. E., 1923a, Occurrence of ground water inthe United States, with a discussion of principles:U.S. Geol. Survey Water-Supply Paper 489, 231 p.

__1923b, Outline of ground-water hydrology, withdefinitions: U.S. Geol. Survey Water-Supply Paper494,71 p.

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Moore, E. W., 1940, Progress report of the committee onquality tolerances of water for industrial uses: NewEngland Water Works Assoc. Jour., v. 54, p. 261-272.

Mount, J. R., Rayner, F. A., Shamburger, V. M., Jr.,Peckham, R. C., and Osborne, F. L., Jr., 1967,Reconnaissance investigation of the ground-waterresources of the Colorado River basin, Texas: TexasWater Devel. Board Rept. 51,107 p.

Railroad Commission of Texas, 1966, Annual report ofthe Oil and Gas Division, 1965: Railroad Comm.Texas, 562 p.

Rayner, F. A., 1959, Records of water-level measure­ments in Crockett, Glasscock, Reagan, Upton, andTerrell Counties, Texas, 1937-57: Texas Board WaterEngineers Bull. 5903, 35 p.

Reeside, J. B., Jr., and others, 1957, Correlation of theTriassic Formations of North America exclusive ofCanada: Geol. Soc. American BulL, v. 68, no. 11, p.1451-1514.

- 53-

Sellards, E. H., Adkin~;, W. S., and Plummer, F. B., 1932,Stratigraphy, v. 1 of The geology of Texas: Univ.Texas Bull. 3232, 1007 p.

Shafer, G. H" 1956 Ground-water resources of theCrane Sandhills, C-ane County, Texas: Texas BoardWater Engineers Bu II. 5604, 104 p.,

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Theis, C. V., 1935, The relation between the lowering ofthe piezometric surface and the rate and duration ofdischarge of a well using ground-water storage: Am.Geophys. Union Tr.ms., v. 16, pt. 2, p. 519-524.

__1964, Ground water in southwestern region, inFluids in subsurfacl~ environments, 1965: Am., Assoc.Pet. Geologists Memoir 4, p. 327-341.

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