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POTENTIAL WATER-WELL SITES FOR THE TOWNS OF FRANNIE AND DEAVER, WYOMING

February 15, 1985

WESTERN WATER CONSULTANTS, INC. CONSULTANTS IN ENGINEERING HYDROLOGY AND HYDROGEOLOGY

P.O. Box 4128 P.O. Box 3042 lAramie, Wyoming 82071 Sheridan, Wyoming 82801 ~;~·;.-;,t'o-;:·-~.:-.i~,:~, (307) 742-0031 (307) 672-0761

MEMBER

FIRM POTENTIAL WATER-WELL SITES FOR THE TOWNS OF FRANNIE AND DEAVER, WYOMING

February 15, 1985

Prepared for: Town of Frannie Frannie, Wyoming 82423 and Town of Deaver Deaver, Wyoming 82421

Prepared by: Western Water Consultants, Inc. 611 Skyline Road 2 North Main - Suite 405 Laramie, Wyoming 82070 Sheridan, Wyoming 82801 TABLE OF CONTENTS

CHAPTER PAGE I RECOMMENDATIONS. . ... ••• •. .. . .•...•. . . .••...... 1 II INTRODUCTION ...•...•••...... •...... ••...... ••...•. 5 Present Water Supplies •...... •••...... •...... 5 Remed i a 1 Act ions ..•...... •.•...... •...... 6 Basis for Drilling Site Selection ....•...... •.... 8 III SELECTION OF PROPOSED WELL SITES ...... ••.....••••..... 10

Geo logy ...... 10 Hydrogeology...... 15 Aquifer Permeability and Well Yields •••..••• 15 Ground-Water Flow...... 20 Ground-Water Quality...... 22 IV WELL DESIGN, CONSTRUCTION AND TESTING •••..•..••••..... 26

REFERENCES •••••....•..••••••.••••.•.•••••.••••••••••.• 33 LIST OF TABLES

TABLE PAGE

1 Lithology and Regional Ground-Water Characteristics of Rock Units in the Frannie-Deaver Study Area •••....• 16 2 Parameters to be Analyzed in Samples Collected from the Frannie-Deaver Test Well ..•••....••••.....•.•..... 30

3 Drinking Water Quality Standards ...... •.....•••....•• 31

LIST OF FIGURES

FIGURE PAGE

1 Map of the Frannie-Deaver Area, Wyoming and Montana, Showing Recommended Drilling Location ••••••••••••.....• 2 2 Land Ownership in the Vicinity of the Recommended Test Well Site and Possible Delivery Pipeline Routes .•. 4

3 Lithology, Thickness and Age of Rocks in the Frannie-Deaver Area, Northern Bighorn Basin, Wyomi ng ..•.•••••••.••••••••••••••••••••••••••••••••••• 11 4 Generalized Geologic Map of Bedrock in the Vicinity of Frannie and Deaver, Big Horn County, Wyoming and Carbon County, Montana .•••....•.••••....•.•••..••.•.••• 13

5 Schematic Geologic Cross Section Through the Recommended Drilling Locations .••..•.•••••..••••••.... 14

6 Potentiometric Surface Associated with the Madison Aquifer in the Northeastern Big Horn Basin, Wyomi ng ...... 21

7 Total Dissolved Solids in the Madison Aquifer in the Northeastern Big Horn Basin, Wyoming ..••.....•••.•...• 23

8 Design of Proposed Madison Test Well for Frannie and Dea ver, Wyomi ng •••..•...•...... ••••....•.•.•..•..••.•• 27 CHAPTER I RECOMMENDATIONS

It is recommended that the Towns of Frannie and Deaver drill a test well in T9S, R26E, section 29, Carbon County, Montana (Figure 1), and complete the well in the Madison aquifer to test the quantity and quality of ground water available for a municipal supply. Existing information indicates that the Madison aquifer would be reached at a drilling depth of about 2,500 feet; drilling should extend through the upper 300 feet of the aqu i fer. The Madi son aqui fer at the test site should have a potentiometric head about 150 feet above the land surface. Based on the specific capacity measured at Cowley's Madison No. 1 well about 8 miles southeast of the proposed Frannie-Deaver wellsite and the drawdown available at the proposed well-site, the proposed well would flow at a rate of about 300 gallons per minute. Water quality data for Madison waters in the area suggest that the water from the proposed well would contain less than 500 milligrams per liter (mg/l) total dissolved solids and less than 5 pico Curies per liter (p Ci/l) Radium. The well should be drilled to the top of the Madison aquifer with a

10 3/4-;nch drill bit, and cased with 8 SIB-inch 0.0. casing which would be cemented in place. The well should then be drilled about 300 feet into the Madison aquifer with a 6 3/4-inch drill bit. No well screen would be required. This recoll111ended construction would facilitate installation of a large variety of pumps, should one be required in the future, and would also allow entry of most workover tools should the well require work in the future.

1 r-R...;.• ...;.2~~E·rlR;.;.,;;.2;..;;,6..;,;E.,;.... ______.....:R.:.:., • .:.;26::...!::.,;E'T' !!.:R.~2:.!..7.!:,E.:..... ____ L..!..S. T.' S.

RECOMMENDED N • WELL SITE

MONTANA _--..,. __.l::"-=-==-====~ 1.!.,.s. WYOMING T.IO S.

/ AREA OF INTEREST

N 'JitANNIE WELL

COWWE\.\.E\.Y ---- T ., .. tI------i----.:~:..L-=---~~-_l ...... T.5IN.

R. 98 W., R. 17 W. R.t? w.1 R.leW. o 2 MI. ,'----'--....' SCALE

FIGURE MAP OF THE FRANNIE - DEAVER AREA, WYOMING AND MONTANA, SHOWING RECOMMENDED DRILLING LOCATION Ownership of land in the vicinity of the recommended wellsite and possible pipeline routes is shown on Figure 2. The recommended wellsite and part of the delivery pipeline that would be in Montana are on land owned by the American Colloid Company. The remainder of the land in Montana that would be crossed by the pipeline ;s owned by the United States Government under the management of the Bureau of Land Management. The portion of the pipeline in Wyoming crosses lands under private ownership by residents of the Frannie area and by Burlington Northern Railroad.

3 N

T 58 N

o 2000 Ft. , I I SCALE

FIGURE 2 : LAND OWNERSHIP IN THE VICINITY OF THE RECOMMENDED TEST WELL SITE AND POSSIBLE DELIVERY PIPELINE ROUTES

4 CHAPTER II INTRODUCTION

This chapter describes the present sources of municipal water for the towns of Frannie and Deaver, problems with those sources, and remedial actions that have been taken in an attempt to alleviate those problems. Also discussed are the criteria used to select a site on which to drill a test hole to explore the possibility of obtaining a new water supply for the towns.

Present Water Supplies

The Town of Franni-e presently obta ins its muni ci pa 1 water supply from a 4,495-foot deep well drilled in 1955 and completed in the upper Madison Formation. The water from this well contains concentrations of Radium-226 that are about nine times the drinking water standard of 5 p CilL established by the United States Environmental Protection Agency (EPA, 1976). Recent analyses have also shown that the total dissolved solids content of the water is 1170 milligrams per liter (mg/L), which exceeds the EPA drinking water quality secondary standard of 500 mg/L. Because of the potential health risks attributed to high concentrations of Radium-226 in the Frannie municipal water supply, EPA has urged the Town to pursue options for solving that problem. The Town of Deaver presently obtains its municipal water supply from Deaver Reservoir, which is fed from the Shoshone River through the Garland canal and the Frannie canal, a major lateral of the Garland

5 cana 1 • Deaver trea ts the water from the reservoi r and pi pes it by gravity two to three miles to town.

Remedial Actions

Western Water Consultants, Inc. was hired by the Town of Frannie to investigate possible solutions to their water-quality problem. In April

1984 the existing well was reamed to remove incrustation inside the casing and was geophysically logged with natural garrma, temperature, ca 1i per, cement bond, and co 11 ar 1ocator tool s. The purpose was to gather detailed well-completion information, evaluate the integrity of the casing and of the cementation of the annulus, and identify zones of anomalously high radioactivity in order to determine the source of the Radium-226. The logs revealed that the casing is corroded and contains holes, and the cement bond between the casing and the well bore is very poor. The combination of these conditions may allow water from formations above the Madison aquifer to enter the well, and it is possible that the Radi um-226 may be enteri ng the we 11 from one of those water-beari ng units. It is also possible, however, that the upper Madison aquifer may be the source of the Radium-226. An attempt was made in August 1984 to isolate and sample water from the Madison aquifer by conducting a packer test on the Frannie well. It was planned to lower a packer on a string of tubing down into the uncased part of the well in the Madison aquifer and inflate the packer to allow only water from the Madison aquifer below the packer to flow up

6 through the tubi ng and to the surface. Water from the i nterva 1 above the packer, which would have included the upper 20 feet of the Madison and the cased part of the well, was to be allowed to flow to the surface between the tubing and the casing. The test would have provided two separate water samples; one from the part of the Madison aquifer below the packer, and another from the uppermost Madison plus any water that might have entered the well through the corroded casing. Both samples were to be analyzed for water quality, and the test would have shown whether the Madi son aqui fer i tse 1f was the source of the Radi um-226.

The tes t fa i 1ed, however, because the 1a rge flow through the sma 11 annular space between the packer tool and the well casing prevented the packer tool from being lowered through the casing. Had the Madi son aqu i fer water been determi ned by wa ter-qua 1i ty analyses not to be the source of the Radium-226 and to have significantly lower dissolved-solids content than water presently produced from the well, the well could have been rehabilitated by cementing a liner inside the existing deteriorated casing. The liner would have excluded water from sources other than the Madison aquifer from entering the well. Because the source of the Radium-226 problem could not be isolated, and in order to minimize disruption of Frannie's water supply, drilling a new well has been determined to be the most attractive alternative. The town of Deaver has explored other alternative sources of supply including participation in either Shoshone Municipal Pipeline or the Cowley Well. The potential of a joint source with the town of Frannie needs to be explored.

7 Basis for Drilling Site Selection

Western Water Consultants, Inc., (WWC) has undertaken selection of a drilling site based on the following criteria: Municipal water demand projected to the year 2030 Ground-water availability, quantity, and quality Accessibility for drilling Apparent feasibility of conveyance of ground-water to the town Cost based on well depth and pipeline length. Water demand was projected to the year 2030 by J.M. Montgomery Consulting Engineers, Inc. in the Draft Big Horn Basin Level II Ground Water Supply Study (Montgomery, 1984, p. 4-5). The combined average water demand for Frannie and Deaver in 2030 is projected to be 82,000 gallons per day (57 gallons per minute), and the peak water demand is projected to be 245,000 gallons per day (170 gallons per minute). Ground-water availability was determined through a study of existing published and unpublished information, including records of the Wyoming State Engineer, the Water Resources Data System at the University of Wyoming, U.S. Geological Survey publications, Montana Bureau of Mines and Geology, Montana Oil and Gas Conservation Corrmis sion, and Montana Department of Natural Resources and Conservation data and publications, and information in the files of Western Water Consu 1 ta nts, Inc. Stereo-pa ired aeri a 1 photography was used to veri fy and modify existing geologic maps, and the resulting maps were checked in the field for accuracy. Numerous wells in the study area were field checked to determi ne water 1eve 1sand, where poss i b1 e, we 11 yi e 1ds to verify existing records.

8 Accessibility for drilling and apparent feasibility for conveyance of the produced ground water by pipeline to the towns were also used as criteria for site selection after a specific aquifer was chosen. Sites that were relatively inaccessible or from which a pipeline route would meet serious topographic obstacles were dropped from further consideration. The costs of drilling a test well and constructing a delivery pipeline were the final criteria affecting the location of a drilling site. Well depth and pipeline length have the strongest effects on cost, and a compromi se was made to a 11 ow for a favorab 1e dri 11 i ng location that also minimizes the length of the pipeline needed to convey the water to the towns. The remainder of this report will focus on specific reasons for well-site selection, and well-design details. The primary topics that will be discussed are hydrogeology and water quality as they relate to site selection and well design, and economic considerations regarding site selection as it affects well design, cost, and conveyance of water from the well to the point of use.

9 CHAPTER III SELECTION OF PROPOSED WELL SITES

This chapter discusses the geologic and hydrogeologic conditions which led to selection of the recommended drilling site shown on Figure 1. The local geology, aquifer units, ground-water flow, and ground-water quality are summarized. The ground-water geology of pa rt of the Franni e-Deaver area was discussed by WWC in a report to the Wyoming Water Development Commission entitled "Ground Water Feasibility Study, Town of Cowley" (WWC, 1982). That report was restricted to the Wyoming part of the northeastern Big Horn basin. Because the Town of Frannie is less than two miles south or the Montana border, this study was extended several miles into Montana (Figure 1) to ensure that no viable ground-water sources would escape consideration.

Geology

The Towns of Franni e and Deaver are located in the northeas tern part of the Big Horn basin, a north-south trending structural depression

that contains up to 33~OOO feet of sedimentary rocks. In the Frannie-Deaver area, about 7,000 feet of those rocks overlie the Precambrian crystalline rock. Figure 3 shows the lithology, thickness, and age of rock units in the area. The lower 1,100 feet of the sedimentary sequence consists of Cambrian shales, limestone pebble conglomerates, and minor sandstone

10 LITHOLOGY FORMATION THICK GEOLOGIC AGE NESS(ft)

(.) o N o Z w (.) ALLUVIUM Df:POSITS ! ~O QUATERNAfitY TERRACE DEPOSITS t 100

LANCE AND MEETEESE 1,000 FORMATIONS UNDIVIDED

MESAVERDE FORMATION 1,100 EXPLANA TION

IGNEOUS, METAMORPHIC

CfUTACEOUS ------::------:----- CODY SHALE 1,710 [2]. SANDSTONE ----=------:..--:. ------:------=------= == -=---- (.) SILTSTONE ...... ::: :::'.':: : ..... :.: ...... : :.' ..... ~ 0 ~ N FRONTIEfit FORMATION 570-750 0 (/) ~ SHALE, CLAYSTONE *#t~*c;~1;l.1~~f~1,\ W ~ ~ =_____ -.: -:::_ -:- _-_-..?-__.7-":-:-::- _-=-~ MOWfitY SHALE 2.0 - 510 §l DOLOMITE t5~-:75~:t:-=r~~:~~~:?]:~ THEfitMOftOLIS SHALE 400 ~~~~~~.:.~~~~~:.::-:-~~~~~;-=::.;..::;~.-;:.~~~~..;~.;:\ CLOVERLY FORMATION 250 E63 LIMESTONE ~~~j=~~£~~~:;~~~~-t~ MORfltlSON FORMATION 425 GYPSUM ------JURASSIC ------STO ------SUNDANCE FORMATION ~ :.'. ~ ------G,lPSUM SPfltING~-.~RM~l~N 130 .... ~ LIMESTONE BRECCIA -- ..... - - ~.. CHUGWATER FORMATION 480 TfitlASSIC

~DINWOODY fOfltMATlgN 30- LIME STONE CONGLOMERATE ""'_1 .1 I .J J ..1 lA0fltMATI IlL. P£RlIAW : .... " OHOSPH~~'t ...... :, - It.N:i -- ~1%== ---~- AMSDEN FORMATION 110- 220 ftENNSLYVANIAN :r, .r. _..:-.;".. " ,,'7 . -: .~ ..... I / / "7'" 7 7 '"7 / 1 -/ '7 .., T 7 "\. - UNCONSOLIDATED SAND, PEBBLES,AND COBBLES I J T " '- MADISON LIMESTONE 150 MISSISSIPPIAN ...... (.)- MAJOR UNCONFORMITY 2RMATION 200 0 DEVONIAN ~I!~ER~ON N //////// //I /I '/I\ - IIGHOfitN-- DOLOMITE 380 0 OfitOOVICIAN //.//.//./ I //77777 w 1,.0,..- --,.,..., -.J ~ ------=------=-- --- ===--- -:.= -::. :::.,-- .,;....:...< GALLATIN FORMATION 500 a.. ------CAMBRIAN GROS VENTfitE FORMATION 510

FLATHEAD SANDSTONE 20 - 50 ...... - -- PfitECAMBRIAN

FIGURE 3 LITHOLOGY, THICKNESS AND AGE OF ROCKS IN THE FRANNIE - DEAVER AREA. NORTHERN BIGHORN BASIN, WYOMING

1 1 and carbonate interbeds. The remaining 1,850 feet of Paleozoic rocks are predominately carbonate and sandstone strata. The overlying Mesozoic rocks, comprising primarily shales with interbedded siltstones and sandstones, attain a maximum thickness of about 6,000 feet. Cre taceous units crop out at the land surface over most of the study area where not covered by Quaternary alluvium. Quaternary units consist of alluvial fans of sand and gravel deposited near the flank of the Pryor Mountains, and stream terraces and alluvium along drainages throughout the study area. Figure 4 shows the generalized geology of the study area. Rock units near and northeast of Frannie dip to the southwest off the flank of the Pryor Mountains. The uniform dip slope that forms the mountain flank is formed mainly on the Madison Limestone; successively younger formations crop out toward the basin in bands roughly parallel to the mountain flank. All the upper Paleozoic and Mesozoic rock units that crop out in the study area dip to the southwest at about 9 degrees (Figure 5). Two prominent geologic structures are present in the study area. The first is the Bear Canyon fault, a northeast-trending fault having a displacement of about 150 feet, with the southeast side downthrown. The other structure is the Big. Pryor Mountain fault and anticline, which is a north-south trending structure showing large displacement with the east side downthrown about 1300 feet.

12 R.26 £.IA. 27 E. EXPLANATION T.9 S. Pzu ~ CODY SHALE

~ FRONTIER FORMATION

MOWRY SHALE AND IKmt I THERMOPOLIS SHALE N B CLOVERLY FORMATION T.9 S. --~~.:J:~==~fI=~ T. 10 S. UNDIVIDED JURASSIC B FORMATION G CHUGWATER FORMATION ...... w ~ UNDIVIDED PALEOZOIC tI------'~~~~:...:..!:.-~~LbI_l.J. T. ~9 N. ~ FORMATION T. ~8 N. Kc CONTACT (Dashed ----~ Where Inferred) FAULT, U=UPTHROWN, D = DOWNT HROWN --~ (Dashed Where Inferred) Kc ----V ANTICLINE AXIS

~ SYNCLINE AXIS

.-----.j~ COW LEY A' A------LINE OF CROSS SECTION R. 98 W.I R. 97 W. R. 97 W I R. 96 W. o, 2, Mi. SCALE

FIGURE 4 : GENERALIZED GEOLOGIC MAP OF BEDROCK IN THE VICINITY OF FRANNIE AND DEAVER, BIG HORN COUNTY. WYOMING AND CARBON COUNTY. MONTANA A

QUA T E R N::A:,::R..:...Y.:;::::::...~ __ EXISTING FRANNIE WELL

FIGURE 5 :SCHEMATIC GEOLOGIC CROSS SECTION THROUGH THE RECOMMENDED DRILLING LOCATIONS (Location of Cross Section Shown on Figure 4) Hydrogeology

The ground-water characteristics of rock units in the Frannie area are listed on Table 1. All water-bearing units which have been reported to yield 200 or more gallons per minute to wells in the northeastern Big Horn basin were investigated as a possible source of ground water for the towns. That criterion limited the investigation to Quaternary-age alluvial deposts, the Tensleep Sandstone, the Madison/Bighorn aquifer, and the Flathead Sandstone. The alluvium was determined not to be a reliable water source because it is subject to possible contamination from surface sources. The Tensleep Sandstone is a significant producer of oil and gas in the Frannie-Deaver area, and water-quality data indicate that the Tensleep ground water has very poor quality (WWC, 1982) • The Madison/Bighorn aquifer is the next-shallowest aquifer likely to meet the requi rements of yi e 1d suffi cient to meet the projected future demand. Because it can meet the yield criterion of 200 gallons per minute and can be reached at a shallower drilling depth than the Fl athead Sandstone, the Madi son/Bi ghorn aqui fer is preferred over the Flathead as a drilling objective.

Aquifer Permeability and Well Yields Yields of wells completed in the Madison Formation range from 5 to 2,040 gpm (WWC, 1982; J.M. Montgomery, 1984). Because the Madison Formation has very small intergranular permeability, its productivity is dependent on secondary permeability associated with open fractures and solution cavities. The occurrence of structurally-induced secondary

15 Table 1. Lithology and Regional Ground-Water Characteristics of Rocks Units in the Frannie-Deaver Study Area, Wyoming. Approximate Geologic Thickness Age Forma t i o_I1 ____---"(_f e_e_t..;.) ______G_e_nera 1 Litho logy Ground-Water Characteristics

Alluvium deposits ±50 Unconsolidated silt, sand, gravel and boulders. Permeability is intergranular and locally Flood platn deposits occurring along stream very large. Variable yields from 5 to 200 channel s. gpm. Water quality is directly related to surface water, and is generally good to fair for domestic use. Recent Quarternary Terrace dep(lsits ±100 Unconsolidated deposits of cobbles, gravel, Yields vary locally from 5 to 25 gpm. Pro sand, and silt occurring above present ductivity is limited by lateral extent of stream levels. terrace deposits. Water quality is related to terrace composition and is generally pOOt for domestic use in the study area.

Undivided Lance 1,000 Lance is massive sandstones interbedded with Intervening confining layers create sands tor and Meeteese claystone. siltstone, shale and minor coal sub-aquifers. Lance-Meeteese sandstones format ions beds. Meeteese is interbedded clayey to yield generally less than 25 gpm. The for silty sandstone, siltstone, claystone and mations occur south and west of the study shale with some bentonite and coal beds. area. Sandstone of the Lance-Meeteetse Sandstones are lenticular. sequence are developed locally for stock anc domestic use. Water quality is generally fair to good for domestic use.

Mesaverde Formation 1,100 Variable sequence of massive sandstone, Interbedded confining shales and permeable thin bedded sandstone shale, carbonaceous sandstones create a series of sub-aquifers. Cretaceous shale and some coal beds. Sandstones are Variable yields due to the lenticular naturE laterally discontinuous. Lowermost unit, of sandstone units. Water quality is very known as the Eagle Sandstone consists poor for domestic use. primarily of fine grained sandstones and shaly sandstones.

Cody Shale 1710 Upper half is dominantly sandy shale and Shales act as aquitards. Sandstones interbedded shaly sandstone. Lower part yield minor amount of water locally. is primarily marine shale with glauconitic sandstone and thin bentonite beds. Table 1. Lithology and Regional Ground-Water Characteristics of Rock Units in the Frannie-Deaver Study Area (continued).

Approximate Geologic Thickness __Age Formation (feet) General litholo9l ______...;.G_r.;;..ou~n_d_-.;...::Water Characteri s tics Frontier Formation 570-750 Sequence of lenticular fine to medium Interbedded confining layers with grained sandstone and argeltaceous sandstone sandstone aquifers. Sandstones yield interbedded with massive to fissile minor quantities of water locally. Water siltstone with lesser bentonite and quality is poor for domestic use. carbonaceous shale. Torchlight Sandstone in upper part and Peay Sandstone in lower pa rt is approx. 100' thick.

Mowry Shale 290-360 Thin-bedded siliceous brittle shale Low permeability shales act as confining interbedded with thin sandstone and layers. No significant water bearing bentonite beds in upper part. zones locally. Brittle shales may develop fracture porosity in areas of Cretaceous faulting and folding and yield minor (continued) quantities of water locally.

Thennopo 1; s 400 Dominantly soft shale with lesser bentonite Low permeability shales act as an aqui Shale beds and sandy and silty zones. Muddy sand- tard. Muddy Sandstone yields minor amounts stone member approximately 151 thick occurs of water. about 200 1 above base • ...... """-I Cloverly Formation 250 Upper sandstone interbedded with silty Upper and lower sandstones are potential sandstone and shale (Dakota Sandstone); aquifers, There is very little development middle shale un;t with occasional sandstone ;n the study area. Water quality is fair lenses; lower lenticular sandstone. con910- to poor for domestic use. meritic sandstone with some siltstone and shale (Lakota Sandstone).

Morrison Formation 425 Variegated claystone and silty sandstone Claystone acts as a confining layer. with lenticular limestone. Sandstone beds yield minor quantities of water locally.

Sundance Formation 370 Interbedded shale, glauconitic sandstone, Low permeability shales and silts react as a Jurassic siltstone, and limestone. confining layer. Sandstone beds produce small yields locally. Table 1. Lithology and Regional Ground-Water Characteristics of Rock Units infue Frannie-Deaver Study Area (continued).

Approximate Geologie Thickness Age Fonnation (feet) Genera 1 Li...:.t_ho;.-l_o"""gy~ ______Ground-Wa ter Characteri_s_t1_' c_S _____ Jurassic Gypsum Springs 130 Dominantly shale and siltstone with thin Low permeability shales act as a confining (continued) Formation limestone beds and massive gypsum beds layer. Solution zones in gypsum beds yield at the base. small amounts of water. Water is very high in dissolved solids.

Chugwater Fonnation 480 Interbedded siltstone, shale. sandstone, Predominantly a confining unit. Sand gypsiferous 1n part stone and gypsum units yield small amounts of water locally. Triassic Oinwoody Formation 30 Siltstone interbedded with silty sandstone No significant water bearing zones. and son~ limestone and dolomite.

Permian Phosphoria 80 Predominantly sandy limestone. cherty dolomite Carbonates yield limited quantities of Fonnation and shale. water. Drill-stem test data indicate local interconnection of Phosphoria and Tensleep aquifers. Water quality is poor fo' domestic use. ------Tensleep Sandstone 140 Massive and crossbedded sandstone with Significant aquifer in the Bighorn Basin wit interbedded dolomite in lower part. yields from 50 to 200 gpm common. Water quality poor away from outcrops. Pennsylvannian Amsden Formation 160-220 Shale and siltstone with interbedded dolomite low permeability shale and siltstone and limestone. Darwin Sandstone member act as confining layers. No signifi locally present at base is about 25 feet thick. cant water-bearing zones except small yields from carbonate units and the basal Darwin Sandstone Member.

Mississippian Mad; son Fonnat i on aso Massive limestone and dolomitic limestone. Major aquifer. High yields in much of Two breccia zones in upper half. the study area. Porosities and permea bilities vary greatly and are highest in areas of fracturing and solution zones. Water quality is good near recharge areas but dissolved solids increase rapidly away from outcrops. Table 1. Lithology and Regional Ground-Water Characteristics of Rock Units in the Frannie-Deaver Study Area, Wyoming (continued).

Approximate Geologic Thickness _.-.:-AglL-e~ ______Forma t i on '-feet) General lithology Ground-Water Characteristics ____ Oevonia" Jefferson Formation 200 Interbedded siltstone. dolomite, and limestone. Carbonate units are potential aquifers in areas of fracturing.

Ordovician Bighorn Dolomite 380 Massive dolomitic limestone and thinly bedded Major water-bearing unit hydrologically dolomite. connected to the Madison Formation. Variable yields related to structural zones of fracturing and solution. No development in the vicinity of the study area; however, scattered wells on the southwestern and southeastern margin of the basin produce significant quantities of water.

Gallatin Formation 500 Interbedded calcareous shale. flat pebble Shales acts as an aquitard. Carbonate and conglomerate and son~ limestone beds. sandstone interbeds may yield minor quantities of water locally. ------Gros Ventre 510 Variable sequence of thin-bedded limestone. Low permeability shales act as an aquitard. Cambrian Formation limestone pebble conglomerate. shale and No significant water bearing zone. Car sandstone beds. bonate units have ground water potential in fractured areas; however, no development is known.

Flathead Sandstone 0-100 Arkosic sandstone and quartz sandstone with Yields up to 2,000 gpm reported along interbedded sandstone in the upper part. the southeastern basin margin. The The formation thins sometimes to extinction occurrence of any significant thickness along highs in the Precambrian basement. of the formation in the study area is questionable.

Precambrian Primarily granitiC and metasedimentary rocks. Not a significant aquifer. permeability in the Madison Formation in areas that have been faulted or folded has been documented by Huntoon (1976) and Vietti (1977), and has been observed in the field during this investigation. Yields of wells producing from the Madison Formation in areas of enhanced permeability are from 10 to 100 times the yields of wells drilled where the Madison Formation possesses only intergranular permeability. Therefore, the selection of a well site for the Towns of Frannie and Deaver also focused on locating geologic structures that would favorably affect permeability and well yield. The effect of such structures on water quality will be discussed later in this report. Structures with the potential for enhancing secondary permeability by fracturing were identified through inspection and modification of existing geologic and structural contour maps (Andrews and others, 1947; Zapp, 1956; Blackstone, 1974; Pierce, 1978). Modifications were made using stereo-paired aerial photography, logs of recently-drilled petroleum test wells, and inspection in the field. The only favorable structure within the study area that has not been tapped by other water wells is the Bear Canyon fault, shown on Figure 4.

Ground-Water Flow Recharge to the Madispn aquifer occurs in outcrop areas by direct infiltration of precipitation, and by infiltration of streamflow and alluvial ground water. The potentiometric surface associated with the Madison aquifer, shown on Figure 6, indicates that ground water flows from recharge areas in the Pryor and Bighorn Mountains toward the center of the Big Horn basin, with local changes caused by geologic structures and oil-field ground-water withdrawals. Ground water flowing through

20 N

o 5 Miles I I SCALE Contour Inter'lol: 200'

EXPLANATION

, SPRING ELEVATION

o WATER WELL DATA 3000 MEASURED POTENTIOMETRIC ELEVATION

PETROLEUM WELL DATA 4000• POTENTIOMETRIC ELEVATION FROM 7 DRILL STEM TEST N ";o'oQ~~~~~i~r~~.... ', __ 3200'.... EOUIPOTENTIAL LINE IN FEET ABOVE MSL CI (Dashed Where Inferred) --3700-- SUPPLEMENTARY CONTOUR

BASE OF MADISON AQUIFER (Aquifer Absent On Hochured Side)

FAULT, HATCHED WHERE FAULT IS NOT EXPOSED AT THE SURFACE

IDEALIZED GROUNDWATER FLOW DIRECTION

, . 1"' .~ . . :( . - ~ .~ ~6r~" .. :- . \. '. R 100 W \\ ~ ... -I'\. R 98 W R 95 W FIGURE 6

POTENTIOMETRIC SURFACE ASSOCIATED WITH THE MADISON AQUIFER IN THE NORTHEASTERN BIG HORN BASIN, WYOMING ( F rom Western Water Consultants, Inc., 1982)

21 the Frannie-Deaver area originates in the Pryor Mountains in the vicinity of Bear Canyon and flows generally southwest. Potentiometric data indicate that, at the Frannie-Deaver wellsite (Figure 1), the Madison aquifer should have approximately 150 feet of head (in feet of water) above the land surface. This circumstance will cause a well at that site to flow at the land surface.

Ground-Water Quality Total dissolved solids content of water in the Madison aquifer in the northeastern Big Horn basin is shown on Figure 7. The dissolved solids content increases basinward, in the direction of ground-water flow. This trend indicates that water quality decreases as the distance of travel from recharge areas and the water's residence time in the aquifer increases. In basin-margin areas where residence time is short, water quality as measured by total dissolved solids content is generally good, whereas in the centra 1 pa rts of the bas i n res i dence times for ground waters are longer and water quality is poor. The area in which the total dissolved sol ids content of Madison aquifer waters is less than the EPA primary drinking water standard of 500 mg/L is shown by cross-hatching on Figure 7. Geologie structures that enhance secondary permeability of the aquifer affect water quality by permitting a local increase in ground-water movement. Because of the water's increased velocity and shortened residence time, the quality of ground water along these structures shou ld be better than the qua 1 i ty of ground water an equa 1 distance from sources of recharge but in areas where the aquifer lacks structurally-enhanced secondary permeability. The site for the

22 N

o SMil .. I , SCALE

EXPLANATION

fI" SPRING DATA 1500 TDS OBTAINED FROM CHEMICAL ANALYSIS OF WATER

o WATER OR PETROLEUM WELL DATA 12.00 TDS OBTAINED FROM CHEMICAL ANALYSIS OF WATER

PETROLEUM WELL DATA 1100• TDS ESTIMATED FROM RESISTIVITY Of FORMATION WATER OR FROM' GEOPHYSICAL ANALYSIS

----500 _ .... TOTAL DISSOLVED SOLIDS CONTOUR IN PARTS PER MILLION (Dashed Where Inferred) LL4'l'//.J'.J' _ BASE OF MADISON AQUIFER ~ (Aquifer Absent On Hochured Side)

APPROXIMATE AREA CONTAINING 6 GROUNDWATER WITHIN DOMESTIC WATER QUALITY STANDARDS N ~ U I 0 FAUL T (U. Uplhrown; D. Downlhrown I

NOTES' DATA OBTAINED FROM CHEMICAL ANALYSIS OF WATER ARE CONSIDERED vERY RELIABLE CONTf

FIGURE 7

TOTAL DISSOLVED SOLIDS IN THE MADISON AQUIFER IN THE NORTHEASTERN BIG HORN BASIN, WYOMING (From Western Water Consultonts, Inc" 1982 )

23 Frannie-Deaver test well is located along the Bear Canyon fault to take advantage of the effect that enhanced secondary permeabi 1i ty has on total dissolved solids content. The Radium-226 content of ground waters in the Big Horn basin has been studied by the U.S. Geological Survey (U.S.G.S.) (lowry, personal communication). U.S.G.S. personnel collected and analyzed 15 water samp 1es from the Wyomi ng pa rt of the bas i n and three from the Montana part. Radium-226 content in pico Curies per liter (p Ci/L) ranged from 0.17 to 437. Waters from areas close to the outcrop were genera lly found to contain smaller concentrations of Radium-226 than waters from the interior of the basin. Regression analysis of the Radium-226 content versus distance from the upper Paleozoic aquifer outcrop showed that a well within about six miles of the outcrop can be expected to contain less than 5 p Ci/l of Radium-226. Removal of radioactive minerals by ground water flowing through the aquifer system ca.n be logically assumed to have occurred to a greater extent in areas havi ng hi gher rates of ground-water flow. Therefore, solution removal of those minerals would be greater in areas where fracture-enhanced secondary permeability is found, such as along faults or folds. The Frannie-Deaver test well ;s located along the Bear Canyon fault and close to the outcrop area of the Madison aquifer to minimize the possibility of discovering water with an unacceptably high content of Radium-226.

24 In summary, the choice of a drilling location for the Towns of Frannie and Deaver was based on the conclusions discussed in the text and listed below: 1. The Madison Formation is the shallowest aquifer that will provide a sufficient quantity of good-quality water for the Towns of Frannie and Deaver. 2. Drilling along a permeability-enhancing structure, the Bear Canyon fault, will increase the productivity of a well. 3. Drilling updip (northeast) along the Bear Canyon fault will decrease the drilling depth to the Madison aquifer. 4. Drilling close to recharge areas will result in production of water of better quality than would be found in basinward areas that are farther from source of recharge. 5. Drilling at the proposed site should produce a flowing well.

25 CHAPTER IV WELL DESIGN, CONSTRUCTION AND TESTING

WWC has designed a test well that will readily and efficiently function as a production well if a sufficient quantity of good-quality water is encountered. The well design is illustrated on Figure 8.

The principal of the design is that cost effectiveness can be a chi eve d by drill i ngal a rg e -d i a me t e rho 1e and ins tall i ng the 1a rg est casing possible. Substantial savings would be realized by avoiding the cost of reaming a small-diameter test hole to a diameter large enough to accept a casing that could accommodate a pump, and flexibility would be provided for any future workovers. That flexibility would not be provided by a small-diameter well. The basic course of action would be to drill a 20-inch diameter hole to a depth of 60 feet. Sixteen-inch surface casing of J-55 or K-55 grade steel would then be cemented in place and the cement allowed to cure. Below the 16-inch surface casing, a 10 3/4-inch hole would be drilled to the top of the Madison Formation, approximately 2500 feet below the land surface. At this point, a geophysical log would be run on the open hole. Logs would include resistivity, spontaneous potent i a 1, gamma ray and ca 1 i per. Product; on cas i ng of 8 5/8-i nch diameter, J-55 or K-55 grade steel would then be set to the bottom of the hole and cemented in place. After the cement has cured, a 6 3/4-inch borehole would be drilled approximately 300 feet into the Madison Formation. The Madison Formation is a competent formation, and an open-hole completion is planned, as warranted by successful open-hole completion of other Madison wells in the Big Horn basin.

26 APPROXIMATE DEPTH GEOLOGIC CONSTRUCTION (Feet) FORMATION DETAILS LAND SURFACE o MOWRY v% ~f/ 22- INCH BOREHOLE V~ INCH SURFACE CASING, 60 ~r-./ ~,L.l.L.~~ 16 - ~ J-5 5 OR K-55 GRADE, MINIMUM v ~ 75 Ibs/ft, CEMENTED THERMOPOLIS ,/

~ ~ 400 v I ~ 10 3 /4-INCH BOREHOLE CLOVERLY ,/ ~ V ~ 630 V ,/ V- I -8 5 /8-INCH CASING, J-55 OR ~ ....: K-5 5 GRADE, MINIMUM 75 Ibs/ft, V' ~ CE MENTED MORRISON V- ,/ ,/ ,/

1060 LI LI SUNDANCE LI ,/ v E XPL ANA TlON 1430 LI GYPSUM SPRINGS v- 1560 LI Vj~ CEMENT I V1 \ SIDE OF BOREHOLE CHUGWATER ,/ v- v V / v v- I I CASING v v 2040 ~ I PHOSPHORIA / MENT: API CLASS G WITH V v CE DINWOODY 2 % CoCI2 2050 v TENSLEEP V- v- V- v 2300 V AMSDEN V ,/ 2500 \.011....., ~

MADISON 6 3 /4-INCH OPEN BOREHOLE

2800 -

FIGURE 8 : DESIGN OF PROPOSED MADISON TEST WELL FOR FRANNIE AND DEAVER, WYOMING

27 The well would be developed by allowing it to flow freely for a period of 24 to 48 hours. Discharge would be measured during the development period to obtain a preliminary estimate of the well's productivity. After the well has been developed and has been shut-in and allowed to recover for a period of at least 7 days, an aquifer test would be conducted to determine aquifer parameters. The test would begin with a reading of the static pressure head. The well would then be tested over a period of 7 or more days by a step-testing procedure wherein the well is allowed to flow at a small rate for an interval to be determined in the field, and then at successively increasing rates during subsequent i nterva 1s. The rates of flow wou 1d be measured wi th respect to time, using a Parshall flume or other applicable method. Following the 7-day flow test, the well would be shut in and measurements of pressure head versus time would be recorded during recovery. Pressure head measurements would be taken at appropriate intervals until the well had recovered to 90 percent of the original static pressure head. Data collected would be plotted and analyzed during the test to provide a means of assessing data quality and to ensure that the test is conducted at appropriate flow rates and for sufficient duration. The data would be analyzed to determine aquifer transmissivity and permeabi lity, well efficiency, and projected yield-drawdown relationships in light of the fractured nature of the aquifer. Special attention will be given to analysis of recharge or barrier boundaries that might affect long-term yield.

28 During the test, the pH, specific conductance, and temperature of the water will be measured at the following. times: beginning of the test, 30 minutes, 1, 7, 3, 4, 8, 16, and 24 hours, and at 24-hour intervals thereafter for the duration of the test. A water sample would be collected midway through the aquifer test and at the end of the test.

The samp 1es wou 1d be ana 1yzed by an EPA-approved 1aboratory for the constituents listed in Table 2. The laboratory results would be compared to the EPA Drinking Water Standards (EPA, 1976), listed in Table 3, to ascertain the suitability of the water as a municipal supply for Frannie and Deaver.

29 Table 2. Parameters to be Analyzed in Samples Collected from the Frannie-Deaver Test Well.

Sample Collected at Sample Collected at Midpoint of Test End of Test

Calcium Calcium Arsenic Magnesium Magnesium Selenium Sodium Sodium Mercury Potassium Potassium Cadmium Carbonate Carbona te Chromium Bicarbonate Bicarbonate Lead Chloride Chloride Si 1ver Total Dissolved Solids Sul fate Barium Specific Conductance Ni tra te Total Alkalinity pH Fluoride Tota 1 Ac idi ty Gross Alpha Boron Gross Alpha Silica Gross Beta Total Carbonate Natural Uranium Total Dissolved Solids Radium-226 Copper Radium-228 Iron pH Manganese Specific Conductance Zinc

30 Table 3. Drinking water quality standards.

Primary Drinkigg Secondary Drinking Constituent Water Standard Water Standard

Arsenic 0.05 Barium 1. Cadmium 0.01 Chloride 250 Chormi urn 0.05 Coliform Bacteria 1 colony/IOO ml b Color 15 color units Copper 1. Corros i vi ty Noncorrosivec Fluoride 2.0d Foaming Agents 0.5 Iron 0.3 Lead 0.05 Manganese 0.05 Mercury 0.002 Nitrate (as N) 10. Odor 3 threshold odor units Herbicides 2,4-0 0.1 2,4,5-TP 0.01 Pesticides Endrin 0.0002 Lindane 0.004 Methoxychlor 0.1 Toxaphene 0.005 pH 6.5-8.5 units Radioactivity Ra-226 + Ra-228 5 pCi/L Gross Alpha 15 pCi/L Tritium 20,000 pCi/L Sr-90 8 pCi/L

31 Table 3. Drinking water quality standards (cont'd).

Primary Drinkigg Secondary Orinkigg Constituent Water Standard \4ater Standard

Selenium 0.01 Silver 0.01 Sodium f Sul fate 250 Total Dissolved Solids 500 Turbidi ty 1 turbidity unitg Zinc 5. a All concentrations in mg/L unless otherwise noted. b The standard is a monthly arithemetic mean. A concentration of 4 colonies/IOO ml is allowed in one sample per month if less than 20 samples are analyzed or in 20 percent of the samples per month if more than 20 samples are analyzed. c The corrision index is to be chosen by the State. d The fluoride standards is temperature-dependent. This standard applies to locations where the annual average of the maximum daily air temperature is 58.4°F to 63.8°F. e The standard includes radiation from Ra-226 but not radon or uranium. f No standard has been set, but monitoring of sodium is recommended. g Up to five turbidity units may be allowed if the supplier of water can demonstrate to the State that higher turbidities do not interfere with disinfection. SOURCE: U.S. Environmental Protection Agency, 1976.

32 REFERENCES

Andrews, D.A., Pierce, W.G., and Eargle, D.H., 1947, Geologic map of the Bighorn Basin, Wyoming and Montana, showing terrace deposits and physiographic features: U.S. Geological Survey Oil and Gas Prelim. Map 71. Blackstone, D.l., Jr., 1974 (1981), Preliminary geologic map of the Bear Canyon 7.5-minute quadrangle, Big Horn County, Montana: Montana Bureau of Mines and Geology Open-file Map MBMG 67, scale 1:24,000. Huntoon, P.W., 1976, Permeability and ground water circulation in the Madison aquifer along the eastern flank of the Bighorn Mountains of Wyoming: Wyoming Geological Association 28th Annual Field Conference Guidebook, Geology and Energy Resources of the Powder River Basin, p. 283-290. J.M. Montgomery Consulting Engineers, Inc., 1984, Big Horn Basin level II Ground Water Supply Study (Draft): Report to Wyoming Water Development Commission, July, 1984. lowrey, M.E., 1984, Personal communications regarding Radium content of Big Horn basin of ground waters analyzed by U.S. Geological Survey: discussions held October 30 and November 1, 1984. Lowry, M.E., Lowman, H.W., and lines, G.C., 1976, Water resources of the Bighorn Bas;n, northwestern Wyoming: U.S. Geological Survey Hydrologic Atlas HA-512, 2 sheets. Manta na Water Resources Boa rd , 1969, Groundwa ter inventory of Ca rbon County, Montana: Montana Water Resources Board, He lena, Montana, 40 p. Pierce, W.G., 1978, Geologic map of the Cody 1°x2° quadrangle, northwestern Wyoming: U.S. Geological Survey map MF-963. U.S. Environmental Protection Agency, 1976. National Interim Primary Drinking Water Regulations: EPA-570/9-76-003, 159 p. Vietti, B.T., 1977, The geohydrology of the Black Butte and Canyon Creek areas, Bighorn Mountains, Wyoming: Unpublished M.S. Thesis, University of Wyoming, 45 pp. Western Water Consultants, Inc., 1982, Ground water development feasibility study, Town of Cowley: Report to Wyoming Water Development Commission, September 30, 1982, 1J4 p. lapp, A.D., 1956, Structure contour map of the Tensleep Sandstone in the Big Horn Basin, Wyoming and Montana: U.S. Geological Survey Oil and Gas Invest. Map OM-182.