Prepared in cooperation with the South Dakota Department of Environment and Natural Resources and the West Dakota Water Development District The Black Hills Hydrology Study —By Janet M. Carter, Daniel G. Driscoll, and Joyce E. Williamson

o Introduction 104o 45' 103 30' Indian Horse o Belle Fourche EXPLANATION 44 45' Reservoir Cr The Black Hills area is an impor- Owl Newell Outcrop of Madison Limestone BELLE Creek Creek tant resource center that provides an Nisland Outcrop of Minnelusa Formation F BELLE FOURCHE OU economic base for western South RCHE RIVER Approximate extent of the Black

Hay Creek R E BUTTE CO Vale Hills area, represented by Dakota through tourism, agriculture, I V ER R MEADE CO REDWAT LAWRENCE CO generalized outer extent of the timber, and mineral resources. Water Cox the outcrop of Inyan Kara Saint Creek Lake Crow Onge Group originating from the area is used for Creek reek municipal, industrial, agricultural, and 30' Gulch Spearfish C Whitewood Bear x Gulch Butte Bottom Creek e recreational purposes throughout ls Bear a Creek F Whitewood Butte Higgins much of western South Dakota. The Cr Creek Squ STURGIS Spearfish a Central Tinton Cr w li Iron CityCr ka ood DEADWOOD l o Black Hills area also is an important Cr w A 103 ad 15' Beaver Cr e D Cr Lead Bear h nnie Cr s A berry recharge area for aquifers in the north- i traw f S r Cr Creek Tilford a hitetail e W p Cheyenne Elk S ern Great Plains. Crossing Little Creek Roubaix ek Creek N Elk re Elk

Little C Population growth, resource devel- . 15' h F Boxelder fis o r r Piedmont a k e Ellsworth R p opment, and periodic droughts have a S Air Force S. Fork Rapid Cr p i Base d Nemo

C Creek r Blackhawk the potential to affect the quantity, Cold S pri Cre ng ek s k Box Elder For Rochford quality, and availability of water s adN o . For Rapid h k Ca R stle RAPID CITY within the Black Hills area. Because Castle Cr Beav e Rapid r k Creek C C ee Pactola r C r of this concern, the Black Hills e re Reservoir e e Creek k k Castle V Deerfield ictoria Creek Hydrology Study was initiated in Reservoir Spring o S. Fork r

44 C l e Cast Rockerville 1990 to assess the quantity, quality, Sheridan Creek Creek Lake and distribution of surface water and Hill City Mt. Rushmore National Keystone Memorial yon an Spring Harney Hayward ground water in the Black Hills area LIMESTONE PLATEAU Iron C Peak n Mountain o x y x

n PENNINGTON CO

n Battle o a Cr of South Dakota. This long-term y Sylvan Spok Hermosa C n CUSTER CO Lake an a Iron e C Creek Creek s le study was a cooperative effort Calamity Grace Bear o B French Peak Creek CUSTER x Gulch Redbird e between the U.S. Geological Survey Gillette idg Creek Cool 45' Jewel Cave CUSTER National (USGS), the South Dakota Depart- Monument Beaver STATE French Fairburn ment of Environment and Natural PARK

Canyon Creek gh Resources, and the West Dakota Water Hi la Lame n Canyon d C Creek o tt Wind Cave o Pringle n Development District, which repre- National Park w Creek o

o

WYOMING d

sented various local and county coop- Wind Johnny

Cave SOUTH DAKOTA SOUTH Dewey Onyx Beaver Creek Cave

erators. This fact sheet describes the Red k Creek

o RIVER Hell o Buffalo Gap r Black Hills Hydrology Study and the 30' B d Creek l

o

C FALL RIVER CO H on ot roo ny major findings of the study. More B k Ca HOT SPRINGS Minnekahta Fall detailed summaries are provided in Oral R

CHEYENNE a lay-reader summary (Carter and Cascade SOUTH DAKOTA Springs others, 2002) and in a technical sum- Black Oahe Hills Reservoir Horsehead M mary (Driscoll and others, 2002). Edgemont iss ou Angostura r i o Creek Reservoir Creek 43 15' d Area oo w River n shown o tt o Igloo Creek Overview of Study C Provo

The Black Hills Hydrology Study was Hat Base modified from U.S. Geological Survey digital data, 01020MILES initiated in 1990 as a partnership among 1:100,000, 1977, 1979, 1981, 1983, 1985 Rapid City, Office of City Engineer map, 1:18,000, 1996 several local, State, and Federal agencies. Universal Transverse Mercator projection, zone 13 01020KILOMETERS The study area for the Black Hills Hydrology Study includes portions of Figure 1. Area of investigation for the Black Hills Hydrology Study.

U.S. Geological Survey USGS Fact Sheet FS-046–02 U.S. Department of the Interior June 2002 six counties in the Black Hills area of about 71 observation wells, 94 precipita- Long-term trends in precipitation for South Dakota (fig. 1). Outcrops of the tion gages, and 60 streamflow-gaging water years 1931-98 for the study area Madison Limestone and Minnelusa stations was used during the data- are illustrated in figure 2; a water year is Formation in South Dakota, which are collection phase. Critical components the 12-month period, October 1 through areas where these geologic formations of this network (primarily observation September 30, and is designated by the occur at the land surface, are shown in wells and selected streamflow-gaging calendar year in which it ends. Annual figure 1. The generalized outer extent of stations) are being maintained for long- precipitation for the study area averages the outcrop of the Inyan Kara Group, term purposes through a cooperative 18.61 inches and has ranged from which approximates the outer extent of program between the USGS and local 10.22 inches in water year 1936 to the Black Hills area, also is shown in and State cooperators. 27.39 inches in water year 1995. The figure 1. A series of 21 reports and 11 maps middle to late 1990’s stand out as the The purpose of the Black Hills have been published as part of the study. wettest period since 1931, which has Hydrology Study was to assess the quan- Hydrologic data collected during the caused potential for bias towards wet tity, quality, and distribution of surface study have been published in various conditions in the data collected in the water and ground water in the Black data reports. Maps (1:100,000 scale) Black Hills during this period. This Hills area of South Dakota. The study have included a hydrogeologic unit map potential bias has been addressed in the was designed as a regional assessment of for the study area, structure-contour analysis of hydrologic data throughout the water resources and was not designed maps for five geologic formations that the course of the study, and has been to address site-specific issues. Because contain major aquifers, and potentiomet- balanced to some extent by relatively dry the Black Hills area is an important ric maps for these major aquifers. Inter- conditions during the late 1980’s and recharge area for several regional bed- pretive reports have addressed water early 1990’s. rock aquifers and various local aquifers, quality and hydrologic conditions for the study concentrated on describing the surface water and ground water. Many Hydrogeologic Setting hydrologic significance of selected bed- of the interpretive reports have dealt rock aquifers. The major aquifers in the specifically with the Madison and Throughout geologic time, the Black Black Hills area are the Deadwood, Minnelusa aquifers, which were a pri- Hills area has experienced frequent Madison, Minnelusa, Minnekahta, and mary focus of the study. Additional periods of inundation by seas, extended Inyan Kara aquifers. The highest prior- information concerning the study and erosion, mountain building, and intrusion ity was placed on the Madison and Minnelusa aquifers, which are widely study products is available at http:// by igneous rocks; thus, the hydrogeology used and interact extensively with the sd.water.usgs.gov/projects/bhhs/ of the study area is very complex. The surface-water resources of the area. BHHS.html. Black Hills uplift formed as an elongated The study consisted of two primary dome about 60 to 65 million years ago. phases—data collection and interpreta- Description of Study Area The oldest geologic units in the study tion. An extensive network consisting of area are the Precambrian crystalline The study area for the Black Hills (igneous and metamorphic) rocks (not Hydrology Study (fig. 1) consists of the shown in fig. 1), which are exposed in topographically defined Black Hills and the central core of the Black Hills, Photograph by Darwin L. Rahder adjacent areas located in western South extending from near Lead to south of Dakota. The Black Hills are situated Custer. The Precambrian rocks generally between the Cheyenne and Belle have low permeability; however, local- Fourche Rivers. The Belle Fourche ized aquifers occur in many locations in River is the largest tributary to the the crystalline core of the Black Hills Cheyenne River. The study area includes most of the larger communities in west- ern South Dakota and contains about one-fifth of the State’s population. 30 Climate

20 The overall climate of the Black Hills area is continental, which is character- ized generally by low precipitation 10 Annual precipitation amounts, hot summers, cold winters, and Long-term average extreme variations in both precipitation (18.61 inches) 0 and temperatures. Local climatic condi- 19301940 1950 1960 1970 1980 1990 2000 ANNUAL PRECIPITATION, IN INCHES PRECIPITATION, ANNUAL tions are affected by topography, with WATER YEAR generally lower temperatures and higher Figure 2. Long-term trends in precipitation for The precipitation gage Mt. Coolidge near precipitation at the higher altitudes. the Black Hills area, water years 1931-98. Custer was operated from 1990-98. where secondary porosity and permeabil- Minnelusa ity have resulted from fracturing and Formation weathering of the rocks. LIMESTONE PLATEAU EXPLANATION Surrounding the Precambrian crystal- Limestone Major aquifer Madison ormation ood F line core is a layered series of sedimen- adw Confining unit De tary rocks including limestones, Spring sandstones, and shales that are exposed Potentiometric surface in roughly concentric rings around the of the Madison aquifer uplifted flanks of the Black Hills, as Alluvial aquifer Precambrian igneous and shown by the outcrops of the Madison metamorphic rocks

Deadwood Water Limestone and Minnelusa Formation table

(fig. 1). The more permeable of these Form Flowing well Spring Inyan Kara ation conduit sedimentary rocks—the Deadwood For- Group Cave M M in inn mation, Madison Limestone, Minnelusa n ekah elu ta Li sa mestone M F Formation, Minnekahta Limestone, and a orma dis tion on Inyan Kara Group—contain major aqui- Limestone Dip of sedimentary rocks exaggerated. fers that are able to store and transmit Relative thickness NOT to scale. large quantities of water and are used extensively for water supplies within and Figure 3. Schematic showing simplified hydrologic setting of the Black Hills area. beyond the study area. Alluvial deposits along streams also commonly are used as local aquifers. The hydrologic setting of the Black Hills area is schematically illustrated in flow in these aquifers is radially away low relief in the western part of the study figure 3. Individually, the major aquifers from the central core of the Black Hills. area known as the “Limestone Plateau” generally are separated by confining lay- The aquifers primarily receive recharge (fig. 4). Most of the headwater springs ers, which are composed of less perme- from infiltration of precipitation on out- occur near the eastern edge of the Lime- able rocks, or by relatively impermeable crops, and the Madison and Minnelusa stone Plateau and provide base flow for layers within the individual units. The aquifers also receive substantial recharge many Black Hills streams. These aquifers and confining units generally from streamflow losses. streams flow across the Precambrian dip away from the flanks of the Black Confined (artesian) conditions gener- igneous and metamorphic rocks in the Hills (fig. 3). In general, ground-water ally exist within the major aquifers, in crystalline core setting. locations where an upper confining layer The loss zone setting (fig. 4) consists is present. Under confined conditions, of areas that are heavily influenced by water in a well will rise above the top of streamflow losses. Most streams gener- Photograph by Van A. Lindquist, West Dakota Water the aquifer in which it is completed. ally lose all or part of their flow as they Development District Flowing wells will result when drilled in cross the outcrop of the Madison Lime- areas where the potentiometric surface stone. Karst features of the Madison (level to which water will rise) is above Limestone, including collapse features, the land surface. Flowing wells and arte- sinkholes, and solution features such as sian springs that originate from confined caves, are responsible for the Madison aquifers are common around the periph- aquifer’s large capacity to accept ery of the Black Hills. recharge from streamflow. Large Surface water in the Black Hills area streamflow losses also occur in many is highly influenced by geologic condi- locations within the outcrop of the tions, and five hydrogeologic settings Minnelusa Formation, and limited losses have been identified that have distinctive probably also occur within the outcrop of influences on streamflow and surface- the Minnekahta Limestone (not shown in water quality. The five settings, which fig. 1). are shown in figure 4, are represented by Large artesian springs originating pri- four areas because two of the settings marily from the Madison and Minnelusa (loss zone and artesian spring) are con- aquifers occur in many locations down- sidered to share a common area. gradient from these loss zones. Thus, the Numerous headwater (water-table) loss zone and artesian spring settings are springs, originating primarily from the represented by the same area (fig. 4). Madison and Minnelusa aquifers, occur These artesian springs provide an impor- Headwater springflow at the eastern edge of in the limestone headwater setting, the Limestone Plateau provides flow to tant source of base flow in many streams Rhoads Fork. which is a high-altitude area of generally beyond the periphery of the Black Hills. No artesian springs are known to be Water-level records have been col- 3,480 Whitewood Madison located beyond the outcrop of the Inyan lected for 71 observation wells com- 3,460 Whitewood Minnelusa Kara Group; thus, the area beyond this pleted in bedrock aquifers and 2 cave 3,440 outcrop is considered to be the exterior sites in the Madison Limestone, provid- setting (fig. 4). ing useful information for hydrologic 3,420

analyses and management of water 3,400 resources. Water levels can be affected WATER LEVEL, Summary of Major Findings 3,380

by several factors including pumping of IN FEET ABOVE SEA LEVEL 1984 1986 1988 1990 1992 1994 1996 1998 CALENDAR YEAR Numerous findings have been pub- nearby wells and climatic conditions. lished in various reports produced for the Long-term water-level declines could Figure 5. Hydrographs illustrating general Black Hills Hydrology Study, of which have various effects, including changes similarities in water levels for a Madison/ Minnelusa well pair near Whitewood. several are highlighted in this fact sheet. in ground-water flow patterns, reduction For more information, readers are of springflow, increased pumping costs, referred to two summary reports for the and dry wells. A large percentage of the study by Carter and others (2002) and observation wells completed in the Driscoll and others (2002). Madison and Minnelusa aquifers respond locations where a hydraulic gradient quickly to climatic conditions. Nearly exists between the aquifers. Artesian all of the hydrographs for these aquifers springflow probably accounts for the show a downward water-level trend prior largest percentage of leakage that occurs. to 1993, as illustrated in the example Streamflow variability is highly influ- hydrographs for a well pair completed in enced by the hydrogeologic settings o 104o 45' 103 30' the Madison and Minnelusa aquifers 44o45' shown in figure 4. For the limestone Newell (fig. 5). This downward trend can be headwater and artesian spring settings, Nisland BELLE FOURCHE partially attributed to dry climatic condi- streamflow variability is small because BUTTE CO Vale MEADE CO tions in the Black Hills area during this LAWRENCE CO of the dominance by ground-water dis- Saint Onge period. Precipitation amounts generally Spearfish charge. The largest headwater springs 30' Bear Whitewood x Butte were above average after 1993, and are in the Rapid Creek and Spearfish water levels increased rapidly (fig. 5) in STURGIS Tinton Central City Creek Basins. The largest artesian DEADWOOD 15' 103o Lead most wells due to the large recharge Tilford spring discharge areas are located near Cheyenne Crossing capacity of the Madison and Minnelusa Roubaix 15' the northern and southern parts of the Piedmont aquifers. In general, there is very little Ellsworth Air Force Base axis of the Black Hills uplift; the single Nemo Cold Blackhawk Spr indication of declining water levels from i ng Cree s k Rochford Box Elder largest discharge area is a complex of RAPID CITY ground-water withdrawals in any of the Bea ve r springs in the northern Black Hills that C r e e k bedrock aquifers in the Black Hills area. 44o includes Cox Lake and Crow Creek. In Rockerville The hydraulic head in the Madison the crystalline core setting, streamflow Hill City Mt. Rushmore National Keystone Memorial and Minnelusa aquifers is similar at the Harney LIMESTONE PLATEAU Iron Hayward Peak characteristics are influenced by direct Mountain

n PENNINGTON CO x x o

y Hermosa

n

a CUSTER CO location for the well pair shown in the C runoff and by relatively small ground- Calamity Peak CUSTER x Redbird example hydrographs (fig. 5) and at vari- water discharge, which tends to diminish 45' Jewel Cave CUSTER National Monument STATE ous other locations throughout the Black Fairburn rather quickly during periods of dry PARK Hills area. However, the hydraulic head climatic conditions. Pringle Wind Cave National Park WYOMING in the aquifers can be separated by sev- Wind In the loss zone setting, most streams

Cave SOUTH DAKOTA SOUTH Onyx Cave Dewey eral hundred feet in some locations. 30' Buffalo Gap provide an important source of recharge FALL RIVER CO Hydraulic connection between the HOT SPRINGS to the Madison and Minnelusa aquifers Minnekahta Oral Madison and Minnelusa aquifers at some because most streams generally lose their Cascade Springs locations in the Rapid City area has been entire flow when crossing out- Edgemont confirmed through aquifer testing and 43o15' crops of the Madison Limestone and

Igloo 01020MILES Provo dye tracing (Greene, 1993, 1997). In the Minnelusa Formation. Unique loss 01020KILOMETERS Spearfish area, aquifer testing provided thresholds (maximum sustainable loss Base modified from U.S. Geological Survey digital data, 1:100,000, 1977, 1979, 1981, 1983, 1985 Rapid City, Office of City Engineer map, 1:18,000, 1996 no indication of hydraulic connection in rates) have been determined for individ- Universal Transverse Mercator projection, zone 13 the vicinity of the tested wells (Greene ual streams, with measured thresholds EXPLANATION Hydrogeologic settings and others, 1999). Hydraulic connection ranging from negligible losses for several Limestone headwater is not known at other locations through- streams to as much as 50 cubic feet per Crystalline core out the Black Hills area because aquifer second (ft3/s) for Boxelder Creek. In the Loss zone and artesian spring—Bounded by exterior setting, streamflow variability is inner extent of Madison Limestone and testing has not been performed. Hydrau- outer extent of Inyan Kara Group lic connection between the Madison and large because streams are heavily influ- Exterior Minnelusa aquifers probably occurs at enced by direct runoff and generally have Figure 4. Hydrogeologic settings for the many artesian spring locations, and only minor influence from ground-water Black Hills area. minor leakage probably occurs at many discharge. Water-quality characteristics for the scale mining activities has occurred in Evapotranspiration ground-water and surface-water Annie, Bear Butte, Squaw, and White- 91.6 percent resources in the Black Hills area were wood Creeks. Approximately 900 aban- Runoff summarized for the study. Water quality doned or inactive mines occur through- 4.9 percent of the major aquifers generally is very out the Black Hills area (South Dakota good in and near outcrop areas but dete- Department of Environment and Natural riorates progressively with distance from Resources, 2001). Potential impacts of the outcrops. In the Minnelusa aquifer, acid-mine drainage include acidic water concentrations of dissolved sulfate vary and increased concentrations of metals, markedly over short distances, where a sulfate, and dissolved solids that can zone of active anhydrite dissolution cause detrimental aquatic effects. Efforts occurs. Most limitations for the use of are underway by Federal, State, and ground water are related to aesthetic private individuals and companies to qualities associated with hardness and remediate problematic sites. Various Precipitation high concentrations of chloride, sulfate, agricultural, urban, and suburban activi- recharge 3.5 percent sodium, manganese, and iron. Very few ties also can degrade stream quality. health-related limitations exist for The total volume of recoverable water Figure 6. Evapotranspiration, runoff, and ground water; most limitations are for stored in the major aquifers (including precipitation recharge as percentages of average annual precipitation. substances associated with radioactive aquifers in the Precambrian rocks) within decay, such as radon and uranium. In the study area is estimated as 256 million addition, high concentrations of arsenic acre-feet (table 1), which is slightly more have been detected in a few samples than 10 times the maximum storage of from the Minnelusa aquifer. Oahe Reservoir on the Missouri River. precipitation in the study area, about Surface-water quality is distinctively Although the volume of stored water is 91.6 percent is returned to the atmo- influenced by the hydrogeologic settings very large, water quality may not be sphere via evapotranspiration, about (fig. 4). For most streams, concentra- suitable for all uses in some parts of the 3.5 percent recharges aquifers in the tions of dissolved solids increase as study area, as previously discussed. study area, and about 4.9 percent streamflow decreases. However, for Hydrologic budgets provide an becomes runoff from the land surface streams in the limestone headwater and accounting of inflows to and outflows (fig. 6). artesian spring settings, which are domi- from a specified area, such as an aquifer The Madison and Minnelusa aquifers nated by ground-water discharge, con- or drainage basin. Hydrologic budgets dominate the ground-water budgets for centrations of dissolved solids have little for ground water and surface water in the the study area. For example, combined variability. Most streams generally meet study area were developed for water average recharge to the bedrock aquifers water-quality standards established for years 1950-98. Of the average annual in South Dakota for 1950-98 was esti- designated beneficial uses. The primary mated as 348 ft3/s, of which 84 percent exceptions are streams in the exterior recharges the Madison and Minnelusa setting, which occasionally fail to meet aquifers. Springflow was estimated as Table 1. Estimated volumes of standards for temperature and dissolved 219 ft3/s, of which 94 percent originates oxygen during low-flow conditions. recoverable water in storage for major aquifers in study area from the Madison and Minnelusa aqui- Standards for suspended sediment also fers. Well withdrawals were estimated as have been exceeded in some streams [From Carter and others, 2002] 40 ft3/s, of which 70 percent is with- (South Dakota Department of Environ- drawn from the Madison and Minnelusa ment and Natural Resources, 1998). Recoverable storage aquifers. Ground-water outflow from the Human influences have the potential Aquifer 3 (million study area was estimated as 89 ft /s, of to degrade water quality for both ground acre-feet) which 65 percent occurs in the Madison water and surface water. For ground and Minnelusa aquifers. Artesian Precambrian 2.6 water, the potential for contamination springflow is the single largest discharge can be large because of development on Deadwood 30.5 component for the Madison and and upgradient of aquifer recharge areas, Minnelusa aquifers, and accounts for large secondary porosity, and relatively Madison 62.7 38 percent of the total discharge from fast flow velocities. Contamination by Minnelusa 70.9 these aquifers. septic tanks has been documented for Large outcrops of the Madison Lime- some wells in the Blackhawk, Piedmont, Minnekahta 4.9 stone and Minnelusa Formation occur in and Sturgis areas (Bartlett and West the Black Hills of Wyoming and were Inyan Kara 84.7 Engineers, Inc., 1998). included in estimating recharge to the For surface water, various land-use Combined storage 256.3 Madison and Minnelusa aquifers. practices can affect water quality. Deg- for major aquifers Recharge to these aquifers for water radation of water quality from large- years 1931-98 in South Dakota and 1,000 Rapid City area, geochemical analyses Photograph by Terry A. Carter

900 indicated that flowpaths in the Madison aquifer are not restricted by surface- 800 water drainage basins, whereby water 700 recharged in the Boxelder Creek and 600 Spring Creek Basins is recovered by

500 wells in the Rapid Creek Basin. Age- dating analyses indicated that ground- 400 water flow velocities in these aquifers 300 are extremely variable.

200 Artesian springs act as a “relief valve” for the Madison and Minnelusa aquifers 100

RECHARGE, IN CUBIC FEET PER SECOND and are an important mechanism in con- 0 19301940 1950 1960 1970 1980 1990 2000 trolling water levels in these aquifers. WATER YEAR Springflow of many large artesian EXPLANATION springs changes very slowly in response Streamflow recharge Average precipitation to long-term climatic conditions. Arte- Precipitation recharge recharge (1931-98) Combined recharge Average combined sian springflow could be diminished by Average streamflow recharge (1931-98) large-scale well withdrawals near recharge (1931-98) springs, thus impacting surface-water Figure 7. Annual recharge (water years resources. Large-scale development of Roughlock Falls along Little Spearfish Creek. 1931-98) to the Madison and Minnelusa aquifers in the Black Hills of South Dakota and the Madison and Minnelusa aquifers has Wyoming (from Carter, Driscoll, and Hamade, the potential to influence the balance of 2001). Prolonged periods of below-average the unique and dynamic “plumbing sys- Greene, E.A., Shapiro, A.M., and Carter, recharge occurred during the 1930’s and tem” in the Black Hills area that controls J.M., 1999, Hydrogeologic character- 1950’s. interactions between ground-water levels ization of the Minnelusa and Madison and artesian springflow. aquifers near Spearfish, South Dakota: U.S. Geological Survey 3 Wyoming averaged about 344 ft /s. References Water-Resources Investigations Annual recharge rates were highly vari- Report 98-4156, 64 p. able (fig. 7) and ranged from about South Dakota Department of Environ- 3 3 Bartlett and West Engineers, Inc., 1998, 62 ft /s in 1936 to about 847 ft /s in Piedmont Valley water quality assess- ment and Natural Resources, 1998, 1995. ment study—Final report: Bismarck, The 1998 South Dakota 303(d) water- Total consumptive use within the N. Dak., Bartlett and West Engineers, body list: Pierre, S. Dak., South study area from both ground-water and Inc. [variously paged]. Dakota Department of Environment surface-water resources was estimated as Carter, J.M., Driscoll, D.G., Williamson, and Natural Resources [variously 3 218 ft /s, which includes well with- paged]. 3 J.E., and Lindquist, V.A., 2002, Atlas drawals of 40 ft /s, reservoir evaporation ———2001, Inactive and abandoned 3 of water resources in the Black Hills of 38 ft /s, and consumptive streamflow mines in the Black Hills, Minerals 3 area, South Dakota: U.S. Geological withdrawals of 140 ft /s. Net tributary Survey Hydrologic Investigations and Mining Program: South Dakota flows, after consumptive streamflow Atlas HA 747, 120 p. Department of Environment and withdrawals, accounted for about Natural Resources, accessed July 13, 3 Driscoll, D.G., Carter, J.M., Williamson, 201 ft /s in the Cheyenne River drainage 2001, at URL http://www.state.sd.us/ 3 J.E., and Putnam, L.D., 2002, Hydrol- basin and about 107 ft /s in the Belle ogy of the Black Hills area, South denr/des/mining/acidmine.htm Fourche River drainage basin. Thus, Dakota: U.S. Geological Survey streamflow contributions from the study Water-Resources Investigations area to the Missouri River amount to Report 02-4094, 150 p. about 4 percent of the average flow of Greene, E.A., 1993, Hydraulic properties For more information, please the Missouri River where it enters South of the Madison aquifer system in the contact: Dakota. western Rapid City area, South In the Madison and Minnelusa aqui- Dakota: U.S. Geological Survey District Chief fers, regional flowpaths from the west Water-Resources Investigations U.S. Geological Survey are largely deflected around the Black Report 93-4008, 56 p. 1608 Mt. View Road Hills. The dominant proportion of water ———1997, Tracing recharge from Rapid City, SD 57702 in these aquifers within the study area is sinking streams over spatial dimen- (605) 355-4560 recharged within the Black Hills area, sions of kilometers in a karst aquifer: with ground-water flow generally radi- Ground Water, v. 35, no. 5, p. 898- http://sd.water.usgs.gov/projects/ ally away from the outcrops. In the 904. bhhs/BHHS.html