U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2012–5183

Prepared in cooperation with the city of Aberdeen

Conceptual and Numerical Models of the 

Glacial Aquifer System North of Aberdeen, 

South Dakota
Front cover. Elm River north of Aberdeen, South Dakota.
Conceptual and Numerical Models of the 

Glacial Aquifer System North of Aberdeen, 

South Dakota

By Katrina A. Marini, Galen K. Hoogestraat, Katherine R. Aurand, and 

Larry D. Putnam

Prepared in cooperation with the city of Aberdeen

Scientific Investigations Report 2012–5183

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2012

For more information on the USGS—the Federal source for science about the Earth, its natural and living 

resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1–888–ASK–USGS.

For an overview of USGS information products, including maps, imagery, and publications, 

visit http://www.usgs.gov/pubprod

To order this and other USGS information products, visit http://store.usgs.gov

Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the 

U.S. Government.

Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials 

as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.

Suggested citation:

Marini, K.A., Hoogestraat, G.K., Aurand, K.R., and Putnam, L.D., 2012, Conceptual and numerical models of the glacial 

aquifer system north of Aberdeen, South Dakota: U.S. Geological Survey Scientific Investigations Report 2012–5183, 

98 p. with appendixes.

ISBN 978–1–4113–3506–6
iii

Contents

Acknowledgments.........................................................................................................................................x

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................1

Purpose and Scope ..............................................................................................................................3

Previous Investigations........................................................................................................................3

Description of Study Area ............................................................................................................................3

Climate and Land Use...........................................................................................................................3

Physiography and Geology .................................................................................................................4

Hydrogeologic Setting .........................................................................................................................4

Conceptual Model of Glacial Aquifer System...........................................................................................9

Hydrogeologic Framework..................................................................................................................9

Elm Aquifer..................................................................................................................................13

Middle James Aquifer...............................................................................................................13

Deep James Aquifer..................................................................................................................20

Groundwater Flow ..............................................................................................................................20

Hydraulic Properties...........................................................................................................................26

Horizontal Hydraulic Conductivity...........................................................................................26

Storage Properties ....................................................................................................................26

Vertical Hydraulic Conductivity ...............................................................................................26

Water Budget Components...............................................................................................................26

Recharge.....................................................................................................................................26

Evapotranspiration ....................................................................................................................29

Interaction with Surface Water...............................................................................................32

Water Use ...................................................................................................................................33

Numerical Model of Groundwater Flow ..................................................................................................33

Calibration Stress Periods.................................................................................................................35

Finite-Difference Grid and Boundary Conditions ..........................................................................35

Representation of Hydraulic Properties .........................................................................................36

Representation of Water Budget Components..............................................................................46

Model Calibration................................................................................................................................46

Calibrated Parameters..............................................................................................................51

Simulated Water Budget Components...................................................................................57

Model Limitations................................................................................................................................58

Summary........................................................................................................................................................59

References Cited..........................................................................................................................................60

Supplement 1. Electromagnetic Geophysical Surveys..........................................................................64

Supplement 2. Direct-Current Electrical Resistivity Geophysical Surveys........................................68

Supplement 3. Aquifer Test of Elm Aquifer at Eyestone Pit ..................................................................77

Supplement 4. Estimates of Hydraulic Conductivity from Specific Capacity Tests ..........................80

Supplement 5. Estimating Vertical Hydraulic Conductivity of Sediments Separating the 

Elm River and Elm Aquifer using Temperature..........................................................................81

Temperature Monitoring....................................................................................................................81

Temperature Modeling Method........................................................................................................82

Temperature Modeling.......................................................................................................................85
iv

Supplement 6. Analysis of Recharge with a Soil-Water-Balance Method........................................92

Supplement 7. Water-Level Data for Generalized Potentiometric Surface of Elm Aquifer.............96

Figures

1. Map showing location of study area and physiographic divisions in eastern

South Dakota .................................................................................................................................2

2. Graph showing cumulative departure of precipitation from monthly averages for

1931–2009 at station 390020 ........................................................................................................4

3. Map showing major land-use categories in model area.......................................................5

4. Map showing land-surface altitude in the model area..........................................................6

5. Map showing geology, landforms, and approximate location of pre-glacial

channels in the model area.........................................................................................................7

6. Map showing the extents of the Elm and Middle James aquifers in model area .............8

7. Map showing location of lithologic logs used in interpretation of hydrogeologic

framework in study area and map of bedrock surface in model area...............................10

8. Map showing glacial aquifer boundaries in model area .....................................................11

9. Map showing thickness of glacial till overlying the Elm aquifer in model area...............12

10. Map showing thickness of the Elm aquifer in model area ..................................................14

11. Map showing combined thickness of sand and gravel deposits within the 

Elm aquifer in model area..........................................................................................................15

12. Map showing altitude of the top of the Elm aquifer in model area ....................................16

13. Map showing thickness of the Middle James aquifer in model area ...............................17

14. Map showing combined thickness of sand and gravel deposits within the 

Middle James aquifer................................................................................................................18

15. Map showing thickness of confining layer 1 in model area................................................19

16. Graph showing hydraulic heads for nested wells A–3 and A–4.........................................20

17. Map showing location of test holes in the Deep James aquifer and interpolated

thickness in model area.............................................................................................................21

18. Map showing generalized average potentiometric surface for the Elm aquifer 

in model area...............................................................................................................................22

19. Map showing distribution of confined and unconfined areas in the Elm aquifer in

model area ...................................................................................................................................23

20. Map showing simulated steady-state potentiometric surface of the 

Middle James aquifer................................................................................................................24

21. Map showing simulated steady-state potentiometric surface of the 

Deep James aquifer...................................................................................................................25

22. Map showing location of aquifer test sites and selected hydrologic features ...............27

23. Map showing location of temperature monitoring sites and piezometers in model

area. Location of counties in which vertical hydraulic conductivity studies have

been conducted ..........................................................................................................................28

24. Map showing spatial distribution of mean annual recharge to the Elm aquifer in

water years 1975–2009, calculated with the soil-water-balance method, in model

area ...............................................................................................................................................30

25. Map showing spatial distribution of average annual potential evapotranspiration

in water years 1975–2009 in model area, calculated by using soil-water-balance

derived potential evapotranspiration, which was modified with a till thickness

multiplier array ............................................................................................................................31
v

26. Graph showing comparison of precipitation, hydraulic head in Elm aquifer for 

wells A–1 and A–2, and stage in Elm River ............................................................................32

27. Map showing location of production wells and South Dakota Department of

Environment and Natural Resources observation wells in model area............................34

28. Map showing boundary conditions for model layer 1..........................................................37

29. Map showing boundary conditions for model layer 2..........................................................38

30. Map showing boundary conditions for model layer 3..........................................................39

31. Graphs showing range in time-variant specified-head boundaries assigned for

model layer 1 for all stress periods..........................................................................................40

32. Graphs showing range in time-variant specified-head boundaries assigned for

model layer 2 for all stress periods..........................................................................................41

33. Graphs showing range in time-variant specified-head boundaries assigned for

model layer 3 for all stress periods..........................................................................................42

34. Map showing mean hydraulic head altitudes for wells completed in the 

Middle James aquifer................................................................................................................43

35. Map showing mean of hydraulic head altitudes for wells completed in the 

Deep James aquifer...................................................................................................................44

36. Map showing horizontal hydraulic conductivity zones for model layer 1 and

location of pilot points................................................................................................................45

37. Map showing distribution of recharge parameters in model area as defined by

glacial till thickness....................................................................................................................47

38. Map showing location of vertical conductance sites, river cell parameter 

groups for Elm River and Foot Creek, and drain cell parameter group for 

Moccasin Creek..........................................................................................................................48

39. Map showing location of wells with water-level data used for model calibration

and number of water-level measurements per well.............................................................50

40. Graph showing linear regression between simulated and observed hydraulic

heads for all aquifers .................................................................................................................51

41. Map showing simulated potentiometric surface for average conditions for water

years 1975–2009 and mean difference between simulated and observed transient

hydraulic heads for model layer 1............................................................................................52

42. Graphs showing simulated and observed hydraulic heads for model layer 1 for

long-term observation wells .....................................................................................................53

43. Map showing simulated potentiometric surface of average conditions for water

years 1975–2009 and mean difference between simulated and observed transient

hydraulic heads for model layer 2............................................................................................54

44. Map showing simulated potentiometric surface of average conditions for water

years 1975–2009 and mean difference between simulated and observed transient

hydraulic heads for model layer 3 ...........................................................................................55

45. Map showing calibrated horizontal hydraulic conductivity distribution for model

layer 1 ...........................................................................................................................................56

46. Graph showing simulated recharge and evapotranspiration rates by water year.........58

47. Graph showing simulated gain or loss of groundwater in the Elm aquifer along

the Elm River................................................................................................................................58
vi

Supplement Figures

S1–1. Map showing location of electromagnetic survey lines and wells ...................................65

S1–2. Graph showing relation between percentage of sand and gravel deposits and

apparent electrical resistivity at a frequency of 13,590 hertz ............................................66

S1–3. Map showing apparent electrical resistivity distribution at a frequency of 

13,590 hertz..................................................................................................................................67

S2–1. Map showing location of direct-current electrical resistivity surveys and glacial

landforms .....................................................................................................................................69

S2–2. Resistivity profile for survey 1...................................................................................................70

S2–3. Resistivity profiles for survey 2.................................................................................................71

S2–4. Resistivity profiles for survey 3.................................................................................................72

S2–5. Resistivity profile for survey 4...................................................................................................73

S2–6. Resistivity profile for survey 5...................................................................................................73

S2–7. Resistivity profiles for survey 6.................................................................................................74

S2–8. Resistivity profile for survey 7...................................................................................................74

S2–9. Resistivity profile for survey 8...................................................................................................75

S2–10. Resistivity profile for survey 9...................................................................................................76

S2–11. Resistivity profile for survey 10.................................................................................................76

S3–1. Map showing location of Eyestone Pit, pumping well, and observation wells for

Eyestone Pit aquifer test............................................................................................................78

S3–2. Graph comparing hydraulic head for observation wells Pit1, PZ2, PZ3,and PZ5,

and trends in hydraulic head ....................................................................................................79

S5–1. Photograph showing stainless steel casing and temperature logger...............................81

S5–2. Cross-section representation of relative temperature variation in gaining and

losing stream reaches ...............................................................................................................82

S5–3. Graph showing observed and simulated temperature for site T1......................................86

S5–4. Graph showing observed and simulated temperature for site T2, 2008............................86

S5–5. Graph showing observed and simulated temperature for site T2, 2009............................87

S5–6. Graph showing observed and simulated temperature for site T3......................................87

S5–7. Graph showing observed and simulated temperature for site T4......................................88

S5–8. Graph showing observed and simulated temperature for site T5......................................88

S5–9. Graph showing observed and simulated temperature for site T6......................................89

S5–10. Graph showing observed and simulated temperature for site T7......................................89

S5–11. Graph showing observed and simulated temperature for site T8......................................90

S5–12. Graph showing observed and simulated temperature for site T9......................................90

S5–13. Graph showing observed and simulated temperature for site T10....................................91

S5–14. Graph showing observed and simulated temperature for site T11....................................91

S6–1. Map showing soil type as defined for recharge calculations in

soil-water-balance method.......................................................................................................94
vii

Tables

1. Lithologic log for well A–3.........................................................................................................13

2. Vertical hydraulic conductivity of sediments separating the Elm River and 

Elm aquifer...................................................................................................................................26

3. Vertical hydraulic conductivity of glacial till in eastern South Dakota..............................29

4. Comparison of selected streamflow measurements at U.S. Geological Survey

streamgage 06471510 with mean daily streamflow at U.S. Geological Survey

streamgage 06471500.................................................................................................................32

5. Lithologic log for well A–1.........................................................................................................33

6. Lithologic log for well A–2.........................................................................................................33

7. Summary of seasonal mean daily streamflow at U.S. Geological Survey

streamgage 06471770.................................................................................................................33

8. Estimated water-use rates, for water years 1975–2009 .......................................................35

9. Simulated stress periods, water years 1975–2009................................................................36

10. Hydraulic conductivity parameter zones representing model layer 1...............................46

11. Vertical conductance at selected sites near Elm River.......................................................49

12. Streamflow measurements in the fall at Moccasin Creek at Aberdeen, 

South Dakota ...............................................................................................................................49

13. Calibrated values for model parameters ................................................................................51

14. Simulated water budgets for water years 1975–2009, water year 1976, and water

year 1998 ......................................................................................................................................57

15. Recharge parameter boundaries and calibrated multiplier values ...................................58

Supplement Tables

S1–1. Approximate values and typical ranges of selected properties of some common

geologic materials ......................................................................................................................64

S1–2. Station names and depths of lithologic logs that were compared with

electromagnetic resistivity surveys.........................................................................................66

S2–1. Station names and depths of lithologic logs that were compared with

direct-current electrical resistivity surveys...........................................................................68

S3–1. Pumping rate and time for each stress period ......................................................................77

S3–2. Observed and simulated drawdown for the Eyestone Pit aquifer test..............................79

S4–1. Specific capacity data and estimated hydraulic conductivity for seven

production wells in Aberdeen area .........................................................................................80

S5–1. Piezometers completed in the Elm aquifer near the Elm River...........................................83

S5–2. Darcy velocity, hydraulic gradient, and vertical hydraulic conductivity at

temperature monitoring sites ...................................................................................................84

S5–3. Thermal and physical properties used in the finite-difference approximation of

energy transport .........................................................................................................................85

S6–1. Infiltration rates assigned by soil type and till thickness.....................................................92

S6–2. Interception storage values and depth of root zone assigned by land-cover 

category .......................................................................................................................................95

S7–1. Water-level data for generalized average potentiometric surface of Elm Aquifer.........96
viii

Conversion Factors

Inch/Pound to SI

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

square mile (mi2) 259.0 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2) 

square feet (ft2) 0.09290 square meter (m2)

Volume

gallon (gal) 3.785 liter (L) 

gallon (gal) 0.003785 cubic meter (m3) 

cubic foot (ft3) 0.02832 cubic meter (m3) 

Flow rate

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

gallon per minute (gal/min) 0.06309 liter per second (L/s)

inch per year (in/yr) 25.4 millimeter per year (mm/yr)

foot per second (ft/s) 0.3048 meter per second (m/s)

Hydraulic conductivity

foot per day (ft/d) 0.3048 meter per day (m/d)

Transmissivity*

foot squared per day (ft2/d) 0.09290 meter squared per day (m2/d) 

Conductance

feet squared per day (ft2/d) 0.0929 meter squared per day (m2/d)

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows: 

 °C=(°F-32)/1.8

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 

(NAVD 88).

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Altitude, as used in this report, refers to distance above the vertical datum.

*Transmissivity: The standard unit for transmissivity is cubic foot per day per square foot times 

foot of aquifer thickness [(ft3/d)/ft2]ft. In this report, the mathematically reduced form, foot 

squared per day (ft2/d), is used for convenience.

Water year (WY) is the 12-month period, October 1 through September 30, and is designated by 

the calendar year in which it ends.
ix

Abbreviations and Acronyms

EM electromagnetic

GIS geographic information system

Hz hertz

H/m Henrys per meter

kHz kilohertz

mS/m millisiemens per meter

NAVD88 North American Vertical Datum of 1988

NOAA National Oceanic and Atmospheric Administration

ohm-m ohm-meters

PEST Parameter ESTimation code

R2	 	 	 coefficient of determination

SDDENR South Dakota Department of Environment and Natural Resources

SDDENR-WR South Dakota Department of Environment and Natural Resources Water Rights

 Program

SDGS South Dakota Geological Survey

S/m siemens per meter

SWB soil-water balance

USGS U.S. Geological Survey

WY water year
x

Acknowledgments

The authors thank the city of Aberdeen for support of numerous studies that provided valuable 

information for this work. The South Dakota Department of Environment and Natural Resources 

(SDDENR) Geological Survey (SDGS) drilled test holes and constructed observation wells for 

this study. The SDGS lithologic database was the primary source of data for interpretation of 

the hydrogeologic framework. The city of Aberdeen and the Water Rights Program of the South 

Dakota Department of Natural Resources (SDDENR-WR) provided permitting and water-use 

data. The SDDENR-WR provided long-term water-level data from their groundwater monitoring 

network in the study area.
Conceptual and Numerical Models of the Glacial Aquifer 

System North of Aberdeen, South Dakota

By Katrina A. Marini1, Galen K. Hoogestraat2, Katherine R. Aurand2, and Larry D. Putnam2

1

 South Dakota School of Mines and Technology.

2

 U.S. Geological Survey.

Abstract

This U.S. Geological Survey report documents a conceptual and numerical model of the glacial aquifer system north 

of Aberdeen, South Dakota, that can be used to evaluate and 

manage the city of Aberdeen’s water resources. The glacial 

aquifer system in the model area includes the Elm, Middle 

James, and Deep James aquifers, with intervening confining 

units composed of glacial till.

The Elm aquifer ranged in thickness from less than 1 to 

about 95 feet (ft), with an average thickness of about 24 ft; the 

Middle James aquifer ranged in thickness from less than 1 to 

91 ft, with an average thickness of 13 ft; and the Deep James 

aquifer ranged in thickness from less than 1 to 165 ft, with an 

average thickness of 23 ft. The confining units between the 

aquifers consisted of glacial till and ranged in thickness from 

0 to 280 ft. The general direction of groundwater flow in the 

Elm aquifer in the model area was from northwest to southeast 

following the topography. Groundwater flow in the Middle 

James aquifer was to the southeast. Sparse data indicated a 

fairly flat potentiometric surface for the Deep James aquifer. 

Horizontal hydraulic conductivity for the Elm aquifer determined from aquifer tests ranged from 97 to 418 feet per day 

(ft/d), and a confined storage coefficient was determined to be 

2.4×10-5. Estimates of the vertical hydraulic conductivity of 

the sediments separating the Elm River from the Elm aquifer, 

determined from the analysis of temperature gradients, ranged 

from 0.14 to 2.48 ft/d.

Average annual precipitation in the model area was 

19.6 inches per year (in/yr), and agriculture was the primary 

land use. Recharge to the Elm aquifer was by infiltration of 

precipitation through overlying outwash, lake sediments, and 

glacial till. The annual recharge for the model area, calculated by using a soil-water-balance method for water year 

(WY) 1975–2009, ranged from 0.028 inch in WY 1980 to 

4.52 inches in WY 1986, with a mean of 1.56 inches. The 

annual potential evapotranspiration, calculated in soil-waterbalance analysis, ranged from 21.8 inches in WY 1983 to 

27.0 inches in WY 1985, with a mean of 24.6 inches. Water 

use from the glacial aquifer system primarily was from the 

Elm aquifer for irrigation, municipal, and suburban water 

supplies, and the annual rate ranged from 1.0 to 2.4 cubic feet 

per second (ft3

/s).

The MODFLOW-2005 numerical model represented 

the Elm aquifer, the Middle James aquifer, and the Deep 

James aquifer with model layers 1–3 respectively separated 

by confining layers 1–2 respectively. Groundwater flow was 

simulated with 75 stress periods beginning October 1, 1974, 

and ending September 30, 2009. Model grid spacing was 200 

by 200 ft and boundaries were represented by specified-head 

boundaries and no-flow boundaries. The model used parameter 

estimation that focused on minimizing the difference between 

954 observed and simulated hydraulic heads for 135 wells. 

Calibrated mean horizontal hydraulic conductivity values for 

model layers 1–3 were 94, 41, and 30 ft/d respectively. Vertical hydraulic conductivity values for confining layers 1 and 2 

were 0.0002 and 0.0003 ft/d, respectively. Calibrated specific 

yield for model layer 1was 0.1 and specific storage ranged 

from 0.0003 to 0.0005 per foot. Calibrated mean recharge 

rates ranged from 2.5 in/yr where glacial till thickness was less 

than 10 ft to 0.8 in/yr where glacial till thickness was greater 

than 30 ft. Calibrated mean annual evapotranspiration rate was 

8.8 in/yr. Simulated net streamflow gain from model layer 1 

was 3.1 ft3

/s.

Introduction

The city of Aberdeen in northeastern South Dakota 

(fig. 1) is developing plans and strategies for a sustainable 

water supply. Drought conditions during 2000–2004 and the 

prospect of economic expansion have heightened the need to 

identify additional water-supply alternatives.

The current (2012) primary source of water for the city 

is the Elm River (Janel Ellingson, City of Aberdeen, oral 

commun., 2012). Water is drawn into the water treatment 

plant from the river by an intake located about 6 miles (mi) 

northeast of the city. During low-flow conditions, Willow 

Creek and Elm Lake reservoirs are available to release water 

from storage about 15 and 25 mi upstream, respectively. The 

natural channel of Elm River is used to deliver water to the 

intake at the water treatment plant. Streamflow records for the 
2 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

EXPLANATION

U.S. Geological Survey streamgage

with identification number

National Oceanic and Atmospheric 

Administration precipitation station 

with identification number

# 06471770

! 390020

Base from U.S. Geological Survey digital data, 1995, 1:100,000

Universal Transverse Mercator projection, Zone 14 North

0 2.5 5 10 MILES

0 2.5 5 10 KILOMETERS

Model boundary

#

#

#

#

!

!

!

!

!

!

Columbia Road 

Reservoir

Richmond 

Lake

Willow Lake

Alkali Lake

Foot Creek

Elm River

JamesRiver

Moccasin Creek

£¤281

£¤12

¬«10

06471770

06471510

06471800

06471500

399136 8

399138

391873

391884

390020

390553

Columbia

Westport

Aberdeen

ORDWAY DAM

R. 65 W. R. 64 W. R. 63 W. R. 62 W.

T. 126 N.

T. 123 N.

T. 124 N.

T. 125 N.

45 20'

45 30'

98 30' 98 20'

James

River 

Lowland

Coteau

du

Missouri Coteau

des

Prairies

Lake

Dakota

Plain

SOUTH DAKOTA

Study area

Brown County

Figure 1. Location of study area and physiographic divisions in eastern South Dakota (from Flint, 1955).
Description of Study Area 3

U.S. Geological Survey (USGS) streamgage on the Elm River 

at Westport (streamgage 06471500) for the period 1946–2009 

indicate that flow in Elm River is less than 5.4 cubic feet per 

second (ft3/s) about 50 percent of the time (U.S. Geological 

Survey, 2011). Groundwater is used as a supplemental water 

source in the Aberdeen area. Groundwater is pumped from 

the Elm aquifer, a shallow glacial aquifer, from wells located 

about 7 mi north of Aberdeen. Several new production wells 

have been added in recent years with the future plan of utilizing groundwater and surface-water sources (Janel Ellingson, 

City of Aberdeen, oral commun., 2012).

Periodic drought and potential future increases in water 

use have raised concerns about declining flows in the Elm 

River and water-level declines in the small storage reservoirs, 

as well as in the Elm aquifer. To help address these concerns, 

the USGS, in cooperation with the city of Aberdeen, developed conceptual and numerical models of the glacial aquifer 

system north of Aberdeen to provide a scientific foundation for evaluating and managing the water resources near 

Aberdeen.

Purpose and Scope

The purposes of this report are to describe hydrologic 

field investigations to characterize the properties of the glacial 

aquifer system north of Aberdeen and to document conceptual and numerical models of groundwater flow in the glacial 

aquifer system. The construction and calibration of a numerical model of the glacial aquifer system is described.

Previous Investigations

Rothrock (1955) investigated possible sources of water 

for the city of Aberdeen in response to the drought of 1934, 

during which all forms of surface water were reduced to 

unusable flows. The geology and water resources of Brown 

County (where the city of Aberdeen is located) were documented by Koch and Bradford (1976). This investigation 

defined the spatial extent of three glacial aquifers—the Elm, 

Middle James, and Deep James aquifers—within the study 

area. Tipton (1977) completed a study of the groundwater 

system near Aberdeen to determine whether the Elm or Middle 

James aquifers could provide the city with sufficient water to 

increase or replace the water sources being used at that time. 

Leap (1986) described the geology of Brown County, from 

the surficial glacial deposits to the Precambrian igneous and 

metamorphic rocks, and produced a detailed map of the glacial 

landforms within the county. Emmons (1987) investigated the 

potential well yields of the Elm and Middle James aquifers as 

well as the potential for artificial recharge to the aquifers in 

the James River Basin as part of a study in cooperation with 

the Bureau of Reclamation. Emmons (1990) used a numerical 

model to characterize the glacial aquifer system in the northern 

three-fourths of Brown County. Three glacial aquifer layers 

(Elm, Middle James, and Deep James) were simulated, each 

separated by a confining layer. The maximum steady-state 

recharge rate was determined to be approximately 7.0 inches 

per year (in/yr), and the maximum potential evapotranspiration rate was 35.4 in/yr. Recharge rates were calculated as 

a function of till depth overlying the Elm aquifer. Recharge 

from precipitation accounted for about 95 percent of the water 

entering the glacial aquifer system, and evapotranspiration 

accounted for about 95 percent of water leaving the system 

(Emmons, 1990). Schaap (2000) reported hydraulic properties of the Elm aquifer estimated by using a local aquifer test, 

resulting in a transmissivity of about 24,000 feet squared per 

day (ft2/d), hydraulic conductivity of about 600 feet per day 

(ft/d), and specific yield of about 0.42.

Description of Study Area

The 490-square mile (mi2) study area (fig. 1), located 

in the west-central part of Brown County north of Aberdeen, 

includes a buffer about 3.5 mi wide around the perimeter of 

the glacial aquifer system analyzed with the numerical model 

(model area). The purpose of this buffer area was to include 

selected precipitation stations and observation wells used in 

conceptual model development for the model area. The model 

area was centered on the part of the glacial aquifer system 

identified as most likely to be considered for future groundwater development by the city of Aberdeen. The boundaries 

of the model area were selected to take advantage of as many 

natural hydrologic boundaries for the numerical model as 

possible, and to be distant enough from the potential groundwater development area to minimize the effects of boundary 

conditions on simulations of hypothetical stress on the aquifer 

system.

Climate and Land Use

The climate in the study area is continental with cold 

winters and hot summers. Long-term precipitation and temperature records were available for two National Oceanic and 

Atmospheric Administration (NOAA) precipitation stations, 

390020 and 391873 (fig. 1). Five additional stations in the 

study had records for shorter time periods. Cumulative departure from the long-term (1931–2009) average for monthly 

precipitation at station 390020 (fig. 2) shows periods of below 

average precipitation from 1958–1976 and above average 

precipitation from 1993–2001. Average annual precipitation 

for the 1931–2009 period was 19.6 in/yr (National Climate 

Data Center, 2011). The 1958–1976 period averaged 2.5 in/yr 

less than the long-term average, and the 1993–2001 period 

averaged 4.8 in/yr greater than the long-term average.

Normal average temperatures (1971–2000) for January 

were 8.2 degrees Fahrenheit (oF) at station 391873 and 11.0oF 

at station 390020. The normal average temperatures for July 

were 71.2oF at station 391973 and 72.2oF at station 390020 

(National Climate Data Center, 2011).
4 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

The major land use in the model area is for agriculture 

(fig. 3). About 86 percent of the land in the model area is used 

for cultivated crops, pasture, and hay (Multi-Resolution Land 

Characteristics Consortium, 2011). Developed areas represent 

about 6 percent, wetlands about 5 percent, and other categories 

about 3 percent of the land in the model area.

Physiography and Geology

The study area is located within the James River Lowland 

physiographic division (fig. 1), which is a lowland about 

200 mi long and 50 mi wide drained by the James River with 

local relief rarely exceeding 20 to 30 feet (ft) (Flint, 1955). 

The James River Lowland is located between two coteaus at 

higher altitude, the Coteau du Missouri and the Coteau des 

Prairies (fig. 1). The eastern part of the study area includes the 

Lake Dakota Plain, which is the floor of an abandoned glacial 

lake in the James River Lowland that is about 90 mi long in 

South Dakota. The Lake Dakota Plain, which is the result of 

deposition of fine-grained lake deposits, is flat with local relief 

in many places no more than 10 ft (Flint, 1955). Glaciation in 

Brown County resulted entirely from the southward advance 

of the James Lobe, of late Wisconsin age of the Pleistocene 

Epoch, through the James River Basin (Leap, 1986). As the 

glacial ice receded up the James River Basin, a broad complex 

of recessional moraines, which impounded meltwater from the 

ice sheet, formed ancient Lake Dakota (Leap, 1986). The part 

of the study area to the west of the Lake Dakota Plain consists 

of highlands within the James River Lowland that are mostly 

recessional and ground moraines.

The general extent of the Lake Dakota Plain and the 

highlands is evident on a map of the land-surface altitude 

(U.S. Geological Survey, 2006) in the model area (fig. 4). The 

land-surface altitude in the Lake Dakota Plain is less than 

1,310 ft above the North American Vertical Datum of 1988 

(NAVD 88). The land-surface altitude in the highlands area 

increases from about 1,310 ft adjacent to the Lake Dakota Plain 

to greater than 1,400 ft in the northwest corner of the study 

area. The orientation of the relief in the highlands reflects the 

northeast to southwest orientation of the glacial moraine.

A map of the geology and landforms modified from 

Leap (1986) shows characteristic elements of the glacial 

aquifer system (fig. 5). Recessional moraine landforms are 

more hummocky and rugged than those of ground moraine 

(Leap, 1986). Ground moraine represents a period when the 

glacier retreated at a rapid and steady rate, leaving a smoother 

surface than recessional moraine. The recessional moraine 

was deposited when the ice sheet was at equilibrium, resulting in meltwater moving along the margins of the ice sheet 

forming ridges. As the glacier retreated, meltwater channels formed along what are now the Elm River and Foot 

Creek. The meltwater channels flowed toward ancient Lake 

Dakota creating deltas where the larger grained sediments 

were deposited along the channel or near the mouth and finer 

grained sediments were carried farther out into Lake Dakota. 

The meltwater channels (fig. 5) were larger than the current 

channel, in which flows are much smaller. The approximate 

widths of the meltwater channels are evident from the low 

land-surface altitude along present-day streams (fig. 4). After 

the ice had retreated from the James River Basin, Lake Dakota 

was still receiving water from melting stagnant ice on the 

Coteau du Missouri and Coteau des Prairies (fig. 1), located 

on the edges of James River Lowland (Leap, 1986). Eventually the morainal dam was breached, and Lake Dakota drained 

southward. As the melting ice diminished, flow in the meltwater channel decreased and new smaller channels were formed. 

New paths were established across the Lake Dakota Plain to 

connect to the James River, which was incising into the lacustrine sediments.

Before the Pleistocene Epoch, the Grand-Moreau-Cheyenne channel served as northward drainage in Brown County 

(Leap, 1986). The channel (fig. 5) in the bedrock surface 

was at an altitude of about 1,000 ft in the model area, with 

the highlands on the western side of the model area rising to 

about 1,400 ft and on the eastern side to about 1,200 ft. Minor 

channels might have been tributaries to the main channel; all 

of the channels were modified by the action of the ice and 

meltwater.

Glacial outwash consisting of sorted gravel, sand, and 

silt constitutes the most permeable deposits in the model 

area. Outwash deposited in depressions in the glacial ice has 

limited areal extent and can vary in thickness from a few 

inches to 10 ft (Leap, 1986). Outwash from buried meltwater channels has a larger areal extent and forms a complex 

network of cut and fill sequences that may or may not be 

hydraulically connected. Lower permeability silt, fine sand, 

and clay deposited in ancient Lake Dakota had a combined 

average thickness of about 75 ft in Brown County (Koch and 

Bradford, 1976).

Hydrogeologic Setting

Koch and Bradford (1976) defined the spatial extent of 

three glacial aquifers—the Elm, Middle James, and Deep 

James aquifers—that ranged in depth from 15–100, 40–250, 

-60

-50

-40

-30

-20

-10

0

10

20

1930 1940 1950 1960 1970 1980 1990 2000 2010

Cumulative departure from

average, in inches

Calendar year

Figure 2. Cumulative departure of precipitation from monthly 

averages for 1931–2009 at station 390020. (Data from National 

Climate Data Center, 2011.)
Description of Study Area 5

EXPLANATION

Land-use category (Multi-Resolution Land

Characteristics Consortium, 2011)

Barren land

Cultivated crops

Developed areas, various categories

Forest

Herbaceous grassland

Open water

Pasture or hay

Shrub / scrub

Woody or emergent herbaceous wetlands

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

)

)

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

£¤281

COUNTY ROAD 16

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Columbia

Westport

Aberdeen

Figure 3. Major land-use categories in model area.
6 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

Land-surface altitude from U.S. Geological Survey National 

Elevation Dataset, 2006, 10-meter resolution

0 2 4 MILES

0 2 4 KILOMETERS

EXPLANATION

Land-surface altitude, in feet above North

American Vertical Datum of 1988

1,273 to less than 1,300

1,300 to less than 1,310

1,310 to less than 1,325

1,325 to less than 1,350

1,350 to less than 1,375

1, 375 to less than 1,400

1,400 to less than 1,417

Boundary between physiographic divisions (from Flint, 1955)

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

£¤281

Columbia

Westport

COUNTY ROAD 16

Aberdeen

JAMES RIVER LOWLAND

LAKE DAKOTA PLAIN

Figure 4. Land-surface altitude in the model area.
Description of Study Area 7

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

EXPLANATION

Alluvium

Delta deposits

Ground moraine

Lacustrine silts and clays

Outwash sand and gravel

Recessional moraine

Meltwater channel outline

Lineations

Approximate ancient Grand-Moreau-Cheyenne

channel—Arrow indicates inferred flow direction

Minor channel—Potentially modified by Pleistocene

ice advance and meltwater

Lakes

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS COUNTY ROAD 16

Aberdeen

£¤281

Columbia

Westport

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Figure 5. Geology, landforms, and approximate location of pre-glacial channels in the model area 

(modified from Leap, 1986).
8 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

and 125–390 ft below land surface, respectively. Glacial 

aquifers in the model area consist primarily of outwash 

deposits composed of sorted gravel, sand, and silt. The 

outwash deposits were grouped as three aquifers by Koch 

and Bradford (1976) based on their altitude. The Elm aquifer 

exists between altitudes of about 1,225 and 1,400 ft, and is 

hydraulically connected to the lacustrine deposits underlying the Lake Dakota Plain (Koch and Bradford, 1976; 

Emmons, 1990). The areal extents of the Middle James and 

Elm aquifers as interpreted by Koch and Bradford (1976) are 

shown in figure 6. The Middle James aquifer exists between 

altitudes of about 1,150 and 1,250 ft in the bedrock lowland 

and is lenticular with many clay layers. The Deep James 

aquifer (not shown in fig. 6) exists between altitudes of about 

950 and 1,175 ft in the system of ancient river channels. 

Prior to glaciation in the model area, the Ancient GrandMoreau-Cheyenne Channel in Brown County drained north 

to the Arctic Ocean (Leap, 1986).

Recharge to the Elm aquifer is by infiltration of precipitation through overlying outwash, lake sediments, and till 

(Koch and Bradford, 1976). Recharge is substantially less in 

areas with greater thickness of overlying till (Emmons, 1990). 

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

EXPLANATION

Elm aquifer

Elm aquifer overlies Middle James aquifer

Middle James aquifer

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

£¤281

Columbia

Westport

COUNTY ROAD 16

Aberdeen

45 35'

45 30'

45 40'

98 30' 98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Figure 6. The extents of the Elm and Middle James aquifers in model area (modified from Koch and 

Bradford, 1976).
Conceptual Model of Glacial Aquifer System 9

Recharge to the Middle James aquifer is primarily from 

hydraulic connection with the Elm aquifer (Koch and Bradford, 1976). Most recharge to the Deep James aquifer is from 

overlying aquifers, where they are hydraulically connected 

(Emmons, 1990).

Natural discharge from the Elm aquifer is from evapotranspiration, seepage into the Elm River and Foot Creek, 

hydraulic connection to the Middle James aquifer, and flow 

into lacustrine deposits in the Lake Dakota Plain (Koch 

and Bradford, 1976). Discharge from the Middle James 

aquifer is by percolation to the Deep James aquifer and 

flow into Lake Dakota sediments and till. Discharge from 

the Deep James aquifer is by upward leakage through till to 

overlying aquifers.

The general direction of groundwater movement in the 

Elm aquifer in the model area is from northwest to southeast 

and toward the Elm River and Foot Creek (Koch and Bradford, 1976). Regional simulation of groundwater flow in the 

model area in the Middle James aquifer indicated flow from 

the northwest to the southeast (Emmons, 1990). Data describing groundwater flow in the Deep James aquifer were sparse; 

however, simulated hydraulic heads in the Deep James aquifer 

in northeastern Brown County (Emmons, 1990) indicated a 

fairly flat potentiometric surface in the model area.

Conceptual Model of Glacial Aquifer 

System

The conceptual model describes the overarching hydrogeologic framework, groundwater flow, hydraulic properties, 

and water budget components of the glacial aquifer system. 

The hydrogeologic framework describes the physical dimensions and location of the sand and gravel units that lie within 

the glacial deposits. The aquifer units are separated and 

overlain by glacial till, although windows (areas of missing 

confining material) may exist in some areas. Groundwater 

flow generally is to the southeast in the Elm and Middle James 

aquifers, but is not well known for the Deep James aquifer. 

The aquifers are relatively transmissive where glacial outwash 

sand and gravel is well sorted compared to the lower transmissivity in the glacial till and outwash with interbedded clay 

layers. Recharge and evapotranspiration are the major water 

budget components. Interaction with incised streams exists 

where intervening glacial till is relatively thin.

Hydrogeologic Framework

Lithologic information from the South Dakota Geological Survey (2008) was compiled in a geographic information 

system (GIS) database for the study area (fig. 7) to interpret 

the hydrogeologic framework. Electromagnetic (Supplement 1) and direct-current (Supplement 2) geophysical 

surveys were used as an aid in interpreting the hydrogeology. 

Direct-current electrical resistivity surveys provided information on the depth to the top of the Elm aquifer and the approximate thickness of the aquifer along the survey lines. Some 

surveys were correlated with lithologic logs, which provided 

hydrogeologic references for data from other surveys where 

no wells or test holes had been drilled. The approximate top 

and bottom altitudes of the Elm aquifer from the center of a 

geophysical survey were entered in the GIS database for areas 

where no other aquifer depth and thickness data were available. Surfaces and spatial datasets were interpolated from 

the GIS database that physically describe the altitudes of the 

land surface (fig. 4); thickness of the glacial till overlying the 

Elm aquifer; top and bottom of the Elm, Middle James, and 

Deep James aquifers; and thickness of confining layers. The 

interpolated files were compared with the electromagnetic and 

direct-current geophysical surveys, as well as lithologic logs 

through cross-sections, to ensure that the interpolated surfaces 

were reasonable.

The top of each aquifer was defined as the uppermost 

sand or gravel unit listed in the lithologic log that was within 

the altitude range of that aquifer. Koch and Bradford (1976) 

defined the altitude ranges as 1,400 to 1,225 ft for the Elm 

aquifer; 1,250 to 1,150 ft for the Middle James aquifer; and 

1,175 to 950 ft for the Deep James aquifer. The bottom of 

each aquifer was defined as the lowest extent of sand or gravel 

in the lithologic log that was within the altitude range of the 

aquifer. When sand and gravel units were absent within an 

aquifer range, the thickness within the aquifer range was 

included in the confining layers. This arbitrary datum for each 

aquifer allowed referencing of the lithologic logs necessary 

to provide information on the presence and absence of the 

aquifer during interpolation.

The interpreted boundaries for the Middle James and 

Deep James aquifer were constrained by the bedrock topography (figs. 7 and 8). The eastern boundary for the Elm aquifer 

was defined by the James River, which is at the lowest altitude 

(fig. 4) in the study area. Assumed groundwater flow pathways 

converged on the low area, with the primary discharge being 

to evapotranspiration and no flow across the boundary at the 

low area. In the southeastern part of the model area, the Elm 

aquifer boundary was set at low areas west of the James River 

(fig. 4) where flow across the boundary was assumed to be 

negligible. The boundary of the eastern extent of the Middle 

James aquifer was assumed to be similar to the Elm aquifer 

boundary because of the hydraulic connection to the Elm 

aquifer (fig. 8).

The thickness of glacial till overlying the Elm aquifer 

in the study area ranged from 0 to about 156 ft, with a mean 

thickness of about 30 ft (fig. 9). Approximately 14 percent 

of the aquifer is overlain by till thicker than 50 ft and about 

4 percent is overlain by till thicker than 70 ft. The top of the 

Elm aquifer was interpreted to be the first substantial sand and 

gravel layer that was listed in the lithologic log and that was 

within the altitude range of that aquifer.
10 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Foot Creek

Elm River

JamesRiver

Moccasin Creek

Lithologic log of bedrock altitude, in feet

! Shallow well, bedrock not penetrated

! Less than 950

! 951 to 1,000

! 1,001 to 1,050

! 1,051 to 1,100

! 1,101 to 1,150

! 1,151 to 1,200

! 1,201 to 1,250

! 1,251 to 1,300

! 1,301 to 1,350

! 1,351 to 1,400

Altitude of bedrock, in feet

1,000

1,001 to 1,050

1,051 to 1,100

1,101 to 1,150

1,151 to 1,200

1,201 to 1,250

1,251 to 1,300

1,301 to 1,350

1,351 to1,400

Extent of model area

[Datum is North American Vertical Datum of 1988]

NOTE: Smaller points indicate the 

maximum possible bedrock altitude 

based on the depth penetrated by 

the test hole or well. The color 

scheme is identical to that shown

in explanation.

EXPLANATION

Base from U.S. Geological Survey digital data, 1995, 1:100,000

Universal Transverse Mercator projection, Zone 14 North

0 2 4 6 MILES

0 42 6 KILOMETERS

!

!

!

!

!

!

! !

!

!

! !

! !

!

!

!

!

!

! !

! !

!!!!

!

!

! !

! !

!

! !

! !

!

! ! ! !

!

!

! !

! ! ! ! !

!

!

!

!

!!

!

! !

!

!

!

!

!

!

!

! ! !

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

! ! !

!

!

!

!

!

!

! !

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! ! !

!

!

!

! !

! ! !

!

!

!

!

!

!

!

!

!

!! !

!

!

! !

!

! ! !

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

! !

!

!

!

!

! ! !

! ! !

! !

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! ! ! ! ! ! !

! !

!

!

!

!

!

!

!

!

!!

!

!

!

!

!

! !! ! !

!

!

!

!

!

!

!

!

!

! !

!

!

!

!!

! ! !

!

!

!

!

!

!

!

! !

!

!! !

!

! !

! !

!

!

!

!

!

! ! !

! !

!

! !!!

! ! !

!

!

!

!

!

!

! ! !

! !

! !

!

! !

! ! !

! ! !

!

!

! ! ! ! !

! !

! ! ! !

! ! !

! !

! ! ! !

!

!

!

!

!!!

!

!

!!

! !

!! !

!!! !

!!!

!! ! !

!!

! !

! !!! ! ! ! ! ! ! ! !

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

! !

!

!

! !

!

! !

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

! ! !

! !

!

!

!

!

!

!

!

!

!

! ! !

!

!

! !

! !

!

! !

!

!

!

!

! !

!

!

!

! !

!

!

! !

! !

! !

!

!

!

! !

!

!

!

!

!

!

!

! ! !

!

!

!

!

!

!

! !

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

! ! !

!

!

!

!

!

!

! !

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

! ! !

!

!

!

!

!

!

!

! !

! !

!

!

!

!

!

!

!

!

! !

!

! !

!

!

!

!

!

! ! !

! ! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!!

! ! ! ! ! ! !

! ! !

!

!

! !

!

! !

!

!

!

!

!

!

!

!

!

!

! !

!!!

!

!

!

!

!

! !

! ! !

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

Columbia Road 

Reservoir

Richmond

Lake

Willow Lake

Alkali 

Lake

Aberdeen

£¤281

£¤12

¬«10

R. 65 W. R. 64 W. R. 63 W. R. 62 W.

T. 126 N.

T. 123 N.

T. 124 N.

T. 125 N.

45 20'

45 30'

98 30' 98 20'

Figure 7. Location of lithologic logs used in interpretation of hydrogeologic framework in study area 

and map of bedrock surface in model area.
Conceptual Model of Glacial Aquifer System 11

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

Elm aquifer—Model layer 1

Middle James aquifer—Model layer 2

Deep James aquifer—Model layer 3

EXPLANATION

£¤281

45 35'

45 30'

45 40'

98 30' 98 22'30''

R. 64 W. R. 63 W. R. 62 W.

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

COUNTY ROAD 16

T. 123 N.

T. 124 N.

T. 125 N.

Columbia

Westport

Aberdeen

Figure 8. Glacial aquifer boundaries in model area.
12 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

EXPLANATION

0 to less than 10

10 to less than 20

20 to less than 30

30 to less than 50

50 to less than 156

Thickness of glacial till overlying the Elm aquifer, in feet 

! Lithologic log where top of Elm aquifer was identified

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Elm aquifer ) boundary

) !

!

!

! ! !

! !

! !

!

! !

! !

! ! ! !

! ! !

! !

! ! ! !

!

!

!

!

!!!

!

!

!!

! !

!!!

! !! !

! !!

!! ! !

!!

! !

! ! ! ! ! ! ! ! ! ! ! !

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

! !

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

! ! !

! !

!

!

!

!

!

!

! !

!

!

! !

! !

!

!

!

!

! !

!

!

!

! !

!

!

! !

! !

!

!

!

! !

!

!

!

!

!

!

!

! ! !

!

!

!

!

!

! !

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! ! !

!

!

!

!

!

!

!

! !

! !

!

!

!

!

!

!

!

!

!

! ! !

! ! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!!

!

! ! ! ! ! !

! ! !

!

!

! !

!

! !

!

!

!

!

!

!

!

! !

!!!

!

!

! !

! ! !

!

!

!

!

!

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

£¤281

Columbia

Westport

COUNTY ROAD 16

Aberdeen

Figure 9. Thickness of glacial till overlying the Elm aquifer in model area.
Conceptual Model of Glacial Aquifer System 13

Elm Aquifer

The top of the Elm aquifer was identified in 319 lithologic logs from locations within the model area and was interpolated between the test hole and well locations. The saturated 

sandy units within the Lake Dakota Plain were included in the 

Elm aquifer for modeling purposes because of the hydraulic 

connection between the aquifer and the lacustrine deposits 

underlying the Lake Dakota Plain. The thickness of the Elm 

aquifer ranges from less than 1 to 95 ft, with an average thickness of about 24 ft in the model area (fig. 10). The sand and 

gravel within the Elm aquifer has a maximum thickness of 

93 ft and an average thickness of about 20 ft in the model area 

(fig. 11). About 80 percent of the material composing the Elm 

aquifer is sand and gravel. Most of the lithologic logs listed 

interbeds of finer material with thicknesses of 1 to 10 ft. In the 

northwestern part of the model area, the Elm aquifer has upper 

and lower sand and gravel deposits separated by a till zone 

about 20 to 40 ft thick.

The combined thickness of sand and gravel in the Elm 

aquifer is large in areal extent along the Elm River in the 

central part of the model area. This area corresponds to 

the Elm River meltwater channel. The northwestern part 

of T. 125 N. and R. 63 W., and the center of T. 124 N. and 

R. 64 W. of figure 11, show areas with greater thickness of 

sand and gravel as well; however, relatively few lithologic 

logs were available for the interpolation in these locations. 

Thus, the extent may be overestimated in these areas.

The top of the Elm aquifer is highest in the northwestern part of the model area and generally decreases in altitude 

toward the southeast (fig. 12). The aquifer is thin or commonly 

absent where the altitude of the top of the aquifer is less than 

1,240 ft. The aquifer is characterized as being relatively thin 

at the boundary near the eastern perimeter in the area near the 

James River, which is expected to preclude groundwater flow 

in this area. The Elm aquifer is confined in some areas by the 

overlying glacial till and is unconfined where the overlying 

glacial till is absent or the hydraulic head is below the altitude 

of the top of the Elm aquifer.

Middle James Aquifer

The top and bottom surfaces of the Middle James aquifer 

were interpolated from the lithologic data available for 

192 wells and test holes (fig. 13). Additionally, the bedrock 

contour map of Leap (1986) was used to constrain the aquifer 

extent in areas not covered by lithologic data. The Middle 

James aquifer exists primarily in the eastern one-half of the 

model area and ranges in thickness from less than 1 to 91 ft, 

with an average thickness of 13 ft in the model area (fig. 13). 

The areas where the Middle James aquifer is thickest are 

in southeastern T. 125 N and R. 63 W and directly east and 

west of Aberdeen (fig. 13). These areas become smaller in 

spatial extent when only the thickness of sand and gravel is 

considered (fig. 14). The maximum thickness of combined 

sand and gravel in the Middle James aquifer is 84 ft and 

the average thickness is 9.5 ft. Sand and gravel make up an 

average of 68 percent of the thickness of the Middle James 

aquifer, and the remaining 32 percent is predominantly clay. 

The Middle James aquifer is confined by the overlying glacial 

till.

The hydraulic connection between the Elm aquifer and 

the Middle James aquifer is limited by glacial till separating 

the aquifers (fig. 15). The average thickness of till that makes 

up the confining layer between the aquifers was 56 ft and the 

maximum thickness was 125 ft. Two lithologic logs near the 

western boundary of the Middle James aquifer indicated that 

no glacial till separated the Elm and Middle James aquifers. 

These windows in the confining layer can have a strong effect 

on groundwater flow and they could exist in areas that were 

not identified because of sparse lithologic logs. The lithologic 

log (table 1) for well site A–3 (fig. 15) shows a confining layer 

of about 3 ft. Hydrographs of continuous hydraulic head data 

for nested wells A–3 (screened 62–72 ft below land surface) 

and A–4 (screened 28–38 ft below land surface) show similar 

responses to aquifer inputs and stresses indicating a strong 

hydraulic connection between the aquifers at this location 

(fig. 16).

Table 1. Lithologic log for well A–3.

[Dashed lines separate hydrogeologic units. U.S. Geological Survey station 

number 453359098260101]

Depth below 

land surface 

(feet)

Description Hydrogeologic unit

0–1 Topsoil, black Topsoil

1–15 Sand and gravel, brown

Elm aquifer

15–25 Clay, gray

25–39 Sand and gravel 

39–41 Clay gray

41–54 Sand and gravel, some coal

54–57 Clay, gray Confining layer 1

57–60 Sand and gravel, some coal

Middle James aquifer

60–62 Clay, gray

62–69 Sand and gravel; some layers 

of clay and coal

69–71 Clay, gray

71–73 Gravel

73–74 Clay, gray 

74–82 Gravel and sand 

82–85 Clay, gray

85–107 Sand and gravel, clayey
14 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

EXPLANATION

Less than 10

10 to less than 20

20 to less than 30

30 to less than 50

50 to 95

Thickness of Elm aquifer, in feet 

! Lithologic log where Elm aquifer is known

to be present or absent

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

)

) !

!

!

! ! !

! !

! !

!

! !

! !

! ! ! !

! ! !

! !

! ! ! !

!

!

!

!

!!!

!

!

!!

! !

!!!

! !! !

! !!

!! ! !

!!

! !

! ! ! ! ! ! ! ! ! ! ! !

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

! !

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

! ! !

! !

!

!

!

!

!

!

! !

!

!

! !

! !

!

!

!

!

! !

!

!

!

! !

!

!

! !

! !

!

!

!

! !

!

!

!

!

!

!

!

! ! !

!

!

!

!

!

! !

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! ! !

!

!

!

!

!

!

!

! !

! !

!

!

!

!

!

!

!

!

!

! ! !

! ! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!!

!

! ! ! ! ! !

! ! !

!

!

! !

!

! !

!

!

!

!

!

!

!

! !

!!!

!

!

! !

! ! !

!

!

!

!

!

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

£¤281

Columbia

Westport

COUNTY ROAD 16

Elm aquifer

boundary

Aberdeen

Figure 10. Thickness of the Elm aquifer in model area.
Conceptual Model of Glacial Aquifer System 15

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

EXPLANATION

Less than 10

10 to less than 20

20 to less than 30

30 to less than 50

50 to 93

Thickness of sand and gravel deposits within the Elm aquifer, in feet 

! Lithologic log where Elm aquifer is known to be present or absent

COUNTY ROAD 16

)

) !

!

!

! ! !

! !

! !

!

! !

! !

! ! ! !

! ! !

! !

! ! ! !

!

!

!

!

!!!

!

!

!!

! !

!!!

! !! !

! !!

!! ! !

!!

! !

! ! ! ! ! ! ! ! ! ! ! !

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

! !

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

! ! !

! !

!

!

!

!

!

!

! !

!

!

! !

! !

!

!

!

!

! !

!

!

!

! !

!

!

! !

! !

!

!

!

! !

!

!

!

!

!

!

!

! ! !

!

!

!

!

!

! !

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! ! !

!

!

!

!

!

!

!

! !

! !

!

!

!

!

!

!

!

!

!

! ! !

! ! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!!

!

! ! ! ! ! !

! ! !

!

!

! !

!

! !

!

!

!

!

!

!

!

! !

!!!

!

!

! !

! ! !

!

!

!

!

!

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

£¤281

45 35'

45 30'

45 40'

98 30' 98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Columbia

Westport

Elm aquifer

boundary

Aberdeen

Figure 11. Combined thickness of sand and gravel deposits within the Elm aquifer in model area.
16 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

EXPLANATION

1,381 to 1,400

1,361 to 1,380

1,341 to 1,360

1,321 to 1,340

1, 301 to 1,320

1,281 to 1,300

1,261 to 1,280

1,241 to 1,260

1,225 to 1,240

Altitude of Elm aquifer top, in feet 

£¤281

45 35'

45 30'

45 40'

98 30' 98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Columbia

Westport

COUNTY ROAD 16

Elm aquifer

boundary

Aberdeen

Figure 12. Altitude of the top of the Elm aquifer in model area.
Conceptual Model of Glacial Aquifer System 17

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

EXPLANATION

Less than 10

10 to less than 20

20 to less than 30

30 to less than 50

50 to 91

Thickness of the Middle James aquifer, in feet 

! Lithologic log where thickness of the Middle James 

aquifer is known

)

)

!

!

!

!

! !

!

! !

! ! ! !

!

! !

!

!

!

!

! !

!

!

!

!

!

!

!

!

! !

! !

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

! ! !

!

!

!

!

!

! !

!

! !

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! ! !

!

!

!

!

! !

!

! ! ! !

! ! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!!

!

! ! ! ! ! !

! ! !

!

!

! !

!

!

!

!

!

!

£¤281

45 35'

45 30'

45 40'

98 30' 98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Columbia

Westport

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

COUNTY ROAD 16

Middle James

aquifer

boundary

Aberdeen

Figure 13. Thickness of the Middle James aquifer in model area.
18 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

EXPLANATION

Less than 10

10 to less than 20

20 to less than 30

30 to less than 50

50 to 84

Thickness of sand and gravel deposits within the

Middle James aquifer, in feet 

! Lithologic log where thickness of the Middle James 

aquifer is known

)

)

!

!

!

!

! !

!

! !

! ! ! !

!

! !

!

!

!

!

! !

!

!

!

!

!

!

!

!

! !

! !

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!

!

!

!

! ! !

!

!

!

!

!

! !

!

! !

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! ! !

!

!

!

!

! !

!

! ! ! !

! ! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!!

!

! ! ! ! ! !

! ! !

!

!

! !

!

!

!

!

!

!

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

£¤281

45 35'

45 30'

45 40'

98 30' 98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Columbia

Westport

Aberdeen

COUNTY ROAD 16

Middle James

aquifer

boundary

Figure 14. Combined thickness of sand and gravel deposits within the Middle James aquifer.
Conceptual Model of Glacial Aquifer System 19

0 2 4 MILES

0 2 4 KILOMETERS

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

EXPLANATION

Less than 10

10 to less than 20

20 to less than 30

30 to less than 50

50 to 125

Thickness of confining layer 1, in feet 

! Well site with site identifier A–4

!!

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

£¤281

45 35'

45 30'

45 40'

98 30' 98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Columbia

Westport

Aberdeen

A–4 A–3

COUNTY ROAD 16

Middle James

aquifer

boundary

Figure 15. Thickness of confining layer 1 in model area.
20 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Deep James Aquifer

The extent and thickness of the Deep James aquifer 

initially were determined by using the bedrock contour map 

produced by Leap (1986), which was modified by using the 

lithologic logs for 29 test holes (fig. 17). Using the representation shown in figure 17, the Deep James aquifer is less 

than 1 to 165 ft thick in the model area and has an average 

thickness of 23 ft based on the interpolation. The average 

percentage of sand and gravel deposits in the Deep James 

aquifer was estimated to be about 70 percent. The till between 

the Middle James and Deep James aquifers had a maximum 

thickness of 280 ft and an average thickness of 150 ft. The 

lithologic logs with data describing the Deep James aquifer 

were typically a few thousand feet to several miles from the 

closest lithologic log in any given direction. The great distance 

between some wells, particularly in T. 124 N and R. 63 W, 

prevented characterization of the aquifer with a high degree 

of certainty. The differences between lithologic logs at wells 

124N63W03AAAB and 124N63W02BBBB demonstrate the 

variability in the presence and thickness of the Deep James 

aquifer (fig. 17). At well 124N63W03AAAB, the total thickness of sand and gravel deposits is 12 ft; however, the total 

thickness of sand and gravel at well 124N63W02BBBB, 

located 176 ft away, is 82 ft (fig. 17). The Deep James aquifer 

is confined by the overlying glacial till.

Groundwater Flow

Water-level data for 91 wells completed in the Elm 

aquifer were used to interpolate a generalized average potentiometric surface in the model area (fig. 18). Water-level data 

and associated land-surface altitudes were used to calculate 

hydraulic heads and generate a map of the estimated average 

potentiometric surface (1975–2009). The average hydraulic 

heads for sites with a single water-level measurement that was 

made within the 1975–2009 period, were estimated through 

comparison with nearby observation wells that had long-term 

records (fig. 18). The hydraulic head was adjusted up or down 

on the basis of the change in hydraulic head from average at 

the selected long-term wells. The measured water-level date, 

altitude, and estimated average water-level altitude are listed 

in table S7–1. The ranges in the measured water levels in feet 

for the seven observation wells with records for 1975–2009 

were 8.3 (site 10), 10.3 (site 11), 15.8 (site 21), 20.6 (site 23), 

15.1 (site 41), 8.2 (site 73), and 15.5 (site 86).

Single water-level measurements at 43 of 91 sites were 

made prior to 1975. Although these water-levels were made 

outside the period represented, they were used to estimate the 

generalized potentiometric surface in areas where no other 

data existed. The cumulative departure of monthly precipitation from average (1931–2009) (fig. 2) was used as a guide in 

estimating an average water level for these sites. For example, 

to estimate the average water level for 1975–2009, the water 

level for site 88 measured in 1949 was adjusted down 6 ft on 

the basis of the above average precipitation in the 1940s and 

a comparison to relative water-level changes at nearby site 86 

that had a long-term record (fig. 18; table S7–1). Changes 

made in the estimated average water levels for these sites in 

comparison to the measured water levels was limited to 6 ft 

or less, which was about 50 percent of the average water-level 

fluctuation for the long-term observation wells. These small 

adjustments in the water levels with measurement dates prior 

to 1975 were made to produce a smoothed generalized average 

potentiometric surface (1975–2009).

Groundwater flow in the Elm aquifer generally is to the 

southeast, following the topography and toward the Lake Dakota 

Plain where evapotranspiration is a substantial sink (fig. 18). The 

Elm River, Foot Creek, and Moccasin Creek have gaining reaches, 

as evidenced by the localized flow directions toward these streams.

The confined and unconfined parts of the Elm aquifer are 

defined on the basis of hydraulic head in relation to the altitude 

of the bottom of the glacial till and clay overlying the aquifer. 

Comparison of the estimated average potentiometric surface 

in the Elm aquifer with the top (fig. 12) of the Elm aquifer 

indicates the approximate location of confined and unconfined 

areas (fig. 19). In a large part of the aquifer, the generalized 

potentiometric surface is within 10 ft above or below the top 

of the aquifer where confined or unconfined conditions could 

prevail depending on the local hydraulic head.

The simulated steady-state potentiometric surface for the 

Middle James aquifer (Emmons, 1990) indicated that groundwater flows from the northwest to southeast (fig. 20). The hydraulic 

heads range from about 1,330 ft in the northwest to 1,280 ft in 

the southeast with the distribution of potentiometric contours 

similar to the Elm aquifer. The simulated steady-state potentiometric surface for the Deep James aquifer (Emmons, 1990) 

indicated a relatively flat potentiometric surface with hydraulic 

heads of about 1,320 ft in the northwest to 1,290 ft in the southeast (fig. 21). Available data were too few to characterize the 

potentiometric surface in the Middle James and the Deep James 

aquifers, so maps modified from Emmons (1990) are shown.

1,300

1,301

1,302

1,303

1,304

1,305

1,306

Apr. 

2008

July 

2008

Oct. 

2008

Jan. 

2009

Apr. 

2009

July 

2009

Oct. 

2009

Jan. 

2010

Hydraulic head, in feet above North American

Vertical Datum of 1988 

Date (month/year)

A–4, Elm aquifer, U.S. Geological Survey

station number 453358098260101

A–3, Middle James aquifer, U.S. Geological Survey

station number 453359098260101

EXPLANATION

Figure 16. Hydraulic heads for nested wells A–3 and A–4. (Data 

from U.S. Geological Survey, 2010.)
Conceptual Model of Glacial Aquifer System 21

0 2 4 MILES

0 2 4 KILOMETERS

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

EXPLANATION

Less than 10

10 to less than 25

25 to less than 50

50 to less than 100

100 to 165

Thickness of the Deep James aquifer, in feet 

! Test hole that penetrated the Deep James aquifer

!

!

!

!

!

!

!

!

!

! !

! ! !

!

! !

!

!

!

!

!

! ! !

! ! !

Foot Creek

Elm River

James River

Moccasin Creek

Foot Cr

£¤281

45 35'

45 30'

45 40'

98 30' 98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Columbia

Westport

Aberdeen

124N63W02BBBB

124N63W03AAAB

COUNTY ROAD 16

Deep James

aquifer

boundary

Figure 17. Location of test holes in the Deep James aquifer and interpolated thickness in model area.
22 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

EXPLANATION

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

Well for which single measurement or short record of water-level 

data are available—Number is site identifier in table S7–1

Well for which long-term water-level data are available—Number 

is site identifier in table S7–1

85

4 85

4

86

Groundwater flow direction

Potentiometric contour—Shows average altitude above North American 

Vertical Datum of 1988 at which water level would have stood in tightly 

cased wells, 1975–2009. Dashed where approximately located. Contour 

interval 10 feet

1,300

Approximate location of Lake Dakota Plain in model area

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

Columbia

Westport

Aberdeen

86

73

41

23

21

11

10

3

4

2

1

5 9

8

7

6

56

34

81

16

19

24 25

26

32

33

30

53

63

55

61

45 46 47 39

37

38

40

13

12

15

20

17

18

66 67

57

60

59 58

50

44

51 52

43 42

28

27

22

77

69

71

75 76

82

72 62 74

65 64

31

83 90

80

68 70

84

78

79

89

87

85

88

54

91

48

49

14

29

36

35

£¤281

1,290

1,330

1,340

1,310

1,300

1,320

1,350

1,320

1,310

1,280

1,360

1,290

1,280

1,310

1,340

1,330

1,300

1,300

1,330 1,340 1,350

1,290

1,330

1,340

1,310

1,300

1,320

1,350

1,320

1,310

1,280

1,360

1,290

1,280

1,310

1,340

1,330

1,300

1,300

1,330 1,340 1,350

1,370

1,360

1,350

1,320

1,290

1,330 44

4

4

4

4

4

4

4

4

4

4

4

4

4

4

4 4

4

4 4

4

4 4

4

4

4

4

4 4

4

4

4

4

4

4

4 4

4 4

4

4

4 4

4

4

4 4

4

4 4

4

4

4

4

4

4

4 4

4

4

4

4 4 4 4 4

4

4

4

4

4 4

4

4

4 4

4

4

4

4

4

4

4

4

4

4

4

4

4

4

Elm aquifer

boundary COUNTY ROAD 16

Figure 18. Generalized average potentiometric surface (1975–2009) for the Elm aquifer in model area.
Conceptual Model of Glacial Aquifer System 23

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

EXPLANATION

Confined—Generalized potentiometric surface greater than 10 feet above the top of the Elm aquifer

Transitional—Generalized potentiometric surface at the top of the Elm aquifer to 10 feet above

Transitional—Generalized potentiometric surface at the top of the Elm aquifer to 10 feet below

Unconfined—Generalized potentiometric surface greater than 10 feet below the top of the Elm aquifer

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

£¤281

45 35'

45 30'

45 40'

98 30' 98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Columbia

Westport Elm aquifer

boundary COUNTY ROAD 16

Aberdeen

Figure 19. Distribution of confined and unconfined areas in the Elm aquifer in model area.
24 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

EXPLANATION

Potentiometric contour—Shows altitude above National Geodetic Vertical 

Datum of 1929 of simulated potentiometric surface on the basis of average 

hydrologic conditions, 1972–1982. Contour interval 10 feet. Extent of contours 

are within boundaries used by Emmons (1990)

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

1,300

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

1,290

1,300

1,310

1,320

1,280

1,330

1,300

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

£¤281

Columbia

Westport

COUNTY ROAD 16

Middle James

aquifer

boundary

Aberdeen

Figure 20. Simulated steady-state potentiometric surface of the Middle James aquifer (modified from 

Emmons, 1990).
Conceptual Model of Glacial Aquifer System 25

EXPLANATION

Potentiometric contour—Shows altitude above National Geodetic Vertical 

Datum of 1929 of simulated potentiometric surface on the basis of average 

hydrologic conditions, 1972–1982. Contour interval 10 feet. Extent of contours 

are within boundaries used by Emmons (1990)

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

1,300

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

1,290

1,300

1,310

1,320

1,290

1,290

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

£¤281

Columbia

Westport

Aberdeen

COUNTY ROAD 16

Deep James

aquifer

boundary

Figure 21. Simulated steady-state potentiometric surface of the Deep James aquifer (modified from 

Emmons, 1990).
26 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Hydraulic Properties

The hydraulic properties of the glacial sediments are 

heterogeneous and can vary over several orders of magnitude 

(Cowman, 1996; Davis and others, 1997; Emmons, 1990). 

Glacial outwash that consists of mostly sand and gravel may 

have horizontal hydraulic conductivity values of as much 

as several hundred feet per day, and glacial till may have 

horizontal hydraulic conductivity values several orders of 

magnitude less than 1 ft/d. Vertical hydraulic conductivity 

of glacial outwash is typically much less than horizontal 

hydraulic conductivity because of interbedded layers of fine 

sediments.

Horizontal Hydraulic Conductivity

Horizontal hydraulic conductivity values used in a 

regional simulation of the glacial aquifers in northern Brown 

County (Emmons, 1988) ranged from 10–350 ft/d for the 

Elm aquifer, 59–350 ft/d for the Middle James aquifer, and 

116–350 ft/d for the Deep James aquifer.

The horizontal hydraulic conductivity of the Elm aquifer 

was determined to be 418 ft/d by simulating aquifer tests, 

lasting 6.625 days (Supplement 3), of a sand pit that penetrated the Elm aquifer (fig. 22). Hydraulic conductivity for 

the Elm aquifer determined from analysis of data from seven 

single-well aquifer tests at production wells (fig. 22) for a 

12-hour period averaged 143 ft/d with a range of 97–205 ft/d 

(Supplement 4).

Storage Properties

A storage coefficient of 3.0×10-4 was used for all aquifers 

in the numerical model of the glacial aquifer system in the 

northern three-fourths of Brown County by Emmons (1988). 

The storage coefficient determined from the Eyestone Pit 

aquifer test of the Elm aquifer (Supplement 3) was 2.4×10-5. 

A specific yield value of 0.20 was used for the unconfined 

aquifer on the basis of the report by Emmons (1990).

Vertical Hydraulic Conductivity

The vertical hydraulic conductivities of the aquifer units 

are typically less than the horizontal hydraulic conductivities 

because of interbedded clay layers within the aquifer units; 

however, the discontinuous extent of clay units could result in 

a wide range of plausible values for this parameter. The interpolated confining layers from lithologic logs could represent a 

more continuous connection and omit unidentified windows in 

confining layers.

The hydraulic connection between the Elm River and 

Elm aquifer was investigated for the reach of the Elm River by 

monitoring hydraulic heads in the Elm aquifer and temperature 

changes in the sediments beneath the Elm River (fig. 23), 

which is described in Supplement 5. The estimated vertical 

hydraulic conductivity of the sediments ranged from 0.1 to 

2.5 ft/d (table 2).

Table 2. Vertical hydraulic conductivity of sediments 

separating the Elm River and Elm aquifer.

Temperature 

site identifier

Adjacent 

piezometer 

identifier

Thickness of 

sediment separating 

Elm River and 

Elm aquifer 

(feet)

Vertical 

hydraulic 

conductivity 

(feet per day)

T2 PZ8 17.8 1.0

T5 PZ1 9.9 2.5

T6 PZ3 6.8 0.1

T7 PZ6 6.1 1.3

T8 PZ7 11.2 0.3

T9 PZ9 16.1 1.6

The vertical hydraulic conductivity of the glacial till is 

an important parameter in estimating the hydraulic connection between the glacial aquifers. Studies in counties near and 

surrounding Brown County demonstrate that both weathered 

and unweathered till have large ranges of measured vertical hydraulic conductivity, and that weathered till can have a 

vertical hydraulic conductivity several orders of magnitude 

larger than measured in unweathered till. Vertical hydraulic 

conductivity of glacial till measured in selected counties in 

eastern South Dakota (county locations shown in fig. 23) indicates a range of 1.4×10-1 to 1.4×10-5 (ft/d) (table 3).

Water Budget Components

Given the climate and small human population in the 

study area, it is expected that the major water budget components are infiltration of precipitation and evapotranspiration. 

Discharge to streams and human water use are smaller budget 

components.

Recharge

The spatial and temporal distribution of recharge to the 

Elm aquifer was estimated using a soil-water-balance (SWB) 

method (Westenbroek and others, 2010) that is described in 

Supplement 6. The annual recharge rate for the model area 

calculated using the SWB method for water year (WY) 1975–

2009 ranged from 0.028 inch (in.) in WY 1980 to 4.52 in. 

in WY 1986 with an annual mean recharge rate of 1.56 in. 

Spatial variation in the mean annual recharge (1975–2009) 

ranged from 0 in clayey till areas to 23.7 in/yr in areas with 

coarse surficial soils (fig. 24).
Conceptual Model of Glacial Aquifer System 27

Single well aquifer test site with site identifier

Other sand pits

Eyestone Pit

Elm aquifer observation well with site identifier

Elm River stage-only streamgage with station identification number

EXPLANATION

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 0.5 1 2 MILES

0 1 2 0.5 KILOMETERS

! A–1

! B–1

# 453430098263200

R. 64 W. R. 63 W.

T. 124 N.

T. 125 N.

45 35'

98 30' 98 27'30" 98 25'

45 32'30"

45 37'30"

!

!

!

!

!

!

!

! #!

Elm River

Elm River

Moccasin Creek

391 AVENUE

387 AVENUE

123 STREET

See figure S3–1

Pickus Pit

B–5

J–1

B–6

B–4

B–3 B–1 B–2

453430098263200

A–2 A–1

Figure 22. Location of aquifer test sites and selected hydrologic features.
28 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

EXPLANATION

Piezometer with site identifier

Temperature monitoring site with site identifier

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

"

T1

! PZ1

"

"

""

"

"

"

"

"

""

!

!

!

!

!

!

Elm River

Foot Creek

COUNTY ROAD 16

Aberdeen

James River

Moccasin Creek

Foot Cr

£¤281

45 35'

45 30'

98 30'

45 40'

98 22'30''

KRUSE DAM

ORDWAY DAM

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Columbia

Westport

T9

T8

T5

T7

T2

T6 T3

T10 T11

PZ6

T1

PZ1

PZ8

PZ9

PZ3

PZ7

SPINK

HAND

BROWN

HUTCHINSON

HYDE

MCCOOK

LINCOLN

TURNER

MINNEHAHA

Figure 23. Location of temperature monitoring sites and piezometers in model area. Location of counties in which vertical 

hydraulic conductivity studies have been conducted.
Conceptual Model of Glacial Aquifer System 29

Evapotranspiration

The potential evapotranspiration rate from the Elm 

aquifer also was estimated with the SWB analysis described 

in Supplement 6. In the SWB analysis used here, potential 

evapotranspiration was estimated using only temperature data; 

humidity and wind speed were not considered (Supplement 6). 

Potential evapotranspiration rates reflect the maximum rate 

that could be evapotranspired if the system is not waterlimited (for example, ponded water). Actual evapotranspiration is lower than potential evapotranspiration because the soil 

is usually water-limited during parts of the year. The annual 

potential evapotranspiration rate calculated by using the 

SWB analysis ranged from 21.8 in. in WY 1983 to 27.0 in. in 

WY 1985, with an average of 24.6 in. The SWB analysis for 

this study used spatially uniform climate data because an averaged climate dataset was used for the model area.

Most evapotranspiration would happen where the overlying glacial till is absent or thin. To account for some upward 

movement of water in the glacial till where the hydraulic 

head was near the land surface, a multiplier array, developed 

from an equation used by Emmons (1990), was used to vary 

potential evapotranspiration spatially on the basis of glacial 

till thickness. Emmons (1990) decreased evapotranspiration 

linearly as till thickness, in feet, increased using equation 1:

Evapotranspiration multiplier till thickness = −1

50 (1)

Where the till thickness was greater than 50 ft in the model 

area, the cell in the multiplier array was set to zero. The 

modified average annual potential evapotranspiration during WY 1975–2009 was 11.0 in. over the model area. The 

distribution of modified average annual potential evaporation 

(fig. 25) shows the potential for larger evapotranspiration in 

the southeast part of the model area. The estimated minimum 

annual potential evapotranspiration of 9.8 in. averaged over 

the model area was in WY 1983, and the estimated maximum 

of 12.1 in. was in WY 1985.

Table 3. Vertical hydraulic conductivity of glacial till in eastern South Dakota.

Number 

of wells Till type Vertical hydraulic conductivity, in feet per day Method Original source

Hyde, Hand, Spink, McCook, Hutchinson, Turner, and Lincoln Counties, South Dakota (fig. 23)

3 screen-intake, 

27 core-intake

Non-weathered 2.1×10-5 – 1.3×10-4

5.7×10-5

(range)

(mean)

In situ permeability 

tests analyzed by the 

Hvorslev method

Cowman (1996)

Non-weathered 1.8×10-5 – 2.0×10-4

7.4×10-5

(range)

(mean)

In situ permeability tests 

analyzed by the Luthin 

and Kirkham method

Hand and Hyde Counties, South Dakota (fig. 23)

26 Weathered 2.1×10-2 (median) In situ permeability 

tests analyzed by the 

Hvorslev method

Cravens and Ruedisili 

(1987)

35 Non-weathered 1.2×10-3 (median)

Minnehaha County, South Dakota (fig. 23)

14 screen-intake, 

6 core-intake

Weathered 1.4×10-4 – 1.4×10-1

3.2×10-3

(range)

(mean)

In situ permeability 

tests analyzed by the 

Hvorslev and BouwerRice methods

Davis and others 

(1997)

Transition zone 1.4×10-5 – 1.4×10-2

4.9×10-4

(range)

(mean)

Non-weathered 1.4×10-5 – 1.4×10-4

5.1×10-5

(range)

(mean)
30 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

EXPLANATION

0 to less than 2

2 to less than 4

4 to less than 7

7 to less than 10

10 to less than 24

Mean recharge, in inches per year 

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

£¤281

45 35'

45 30'

45 40'

98 30' 98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Columbia

Westport

COUNTY ROAD 16

Elm aquifer

boundary

Aberdeen

Figure 24. Spatial distribution of mean annual recharge to the Elm aquifer in water years 1975–2009, 

calculated with the soil-water-balance method, in model area.
Conceptual Model of Glacial Aquifer System 31

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

EXPLANATION

0 to less than 5

5 to less than 10

10 to less than 15

15 to less than 20

20 to less than 25

Potential evapotranspiration, in inches per year 

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

£¤281

45 35'

45 30'

45 40'

98 30' 98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Columbia

Westport

COUNTY ROAD 16

Elm aquifer

boundary

Aberdeen

Figure 25. Spatial distribution of average annual potential evapotranspiration in water years 1975–

2009 in model area, calculated by using soil-water-balance derived potential evapotranspiration, which 

was modified with a till thickness multiplier array.
32 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Interaction with Surface Water

Interaction between the Elm aquifer and surface water 

exists primarily where the intervening glacial till is absent 

or thin. Foot Creek and the upper part of the Elm River are 

located in glacial meltwater channels incised into glacial 

recessional and ground moraine (fig. 5). The generalized 

average potentiometric surface (fig. 18) shows a hydraulic 

gradient toward these stream reaches, indicating that groundwater flows from the Elm aquifer to the stream. The range 

in vertical hydraulic conductivity at sites (fig. 23) along the 

Elm River (table 2) ranged from 0.1 to 2.5 ft/d, and the thickness of the intervening sediments ranged from 6.1 to 17.8 ft.

Streamflow records for the USGS streamgage 06471500 

(fig. 1) on the Elm River at Westport for the period 1946–2009 

indicate that flow in Elm River is less than 3 ft3/s about 

30 percent of the time and less than 5 ft3/s about 50 percent of 

the time (U.S. Geological Survey, 2011); therefore, fluctuations in streamflow gain from the Elm aquifer in this reach 

were estimated to be small, and streamflow gain from the Elm 

aquifer was assumed to be less than about 5 ft3

/s.

The reach of the Elm River between the streamgage 

06471500 and the seasonal water-stage gage on the Elm River 

near Ordway (streamgage 06471510) includes a small dam 

(Ordway Dam) and reservoir, which limit quantification of 

streamflow gain or loss; however, comparison of selected field 

measurements of streamflow at streamgage 06471510 (Rantz 

and others, 1982) and mean daily streamflow at streamgage 

06471500 indicates a small streamflow loss to the aquifer 

(table 4). Two field measurements when flow was relatively 

steady indicate that the Elm River was losing streamflow to 

the Elm aquifer of about 1 to 5 ft3

/s.

Interaction between the Elm River and the Elm aquifer 

was examined by comparison of Elm aquifer water levels 

and stage in the Elm River. Observation wells A–1 (table 5) 

and A–2 (table 6) completed in the Elm aquifer and the 

USGS stage-only streamgage 453430098263200 on the 

Elm River (fig. 22) were monitored with continuous recording equipment during 2008–09. Well A–1 is located about 

100 ft east of the streamgage, and well A–2 is about 1,000 ft 

west of the streamgage. Comparison of hydraulic head in 

the Elm aquifer, stream stage in the Elm River, and daily 

precipitation shows the response of the Elm aquifer to 

precipitation (fig. 26). The daily precipitation is for precipitation station 399138 (fig. 1), located about 7 mi upstream on 

the Elm River. The rise in hydraulic head exists for a few 

days following a precipitation event. During flooding in the 

spring of 2009, recording equipment for well A–1 and the 

streamgage were inoperable. When the stream receded, the 

hydraulic head in well A–2 tracked closely with the decrease 

in stage. The altitude of the Elm River stage generally 

ranges between 1,306 and 1,307 ft except during flooding 

conditions. The altitude of the bottom of the Elm River at 

the streamgage was about 1,302 ft, indicating that the river 

bottom was at about the same altitude as the top of the Elm 

aquifer near the Elm River streamgage. The resistivity profile 

for survey 9 (fig. S2–10, Supplement 2), which is located 

adjacent to the Elm River upstream from well A–1, indicated a glacial till thickness of about 15–20 ft. Variability in 

till thickness near the Elm River could result in substantial 

heterogeneity in the hydraulic connection of the stream and 

the Elm aquifer.

Table 4. Comparison of selected streamflow measurements at U.S. Geological Survey streamgage 06471510 with mean daily 

streamflow at U.S. Geological Survey streamgage 06471500.

[ft3/s, cubic feet per second]

Field measurement at station 06471510 Mean daily streamflow at station 06471500, in ft3/s

Date and time Streamflow, 

in ft3

/s

Day prior to 

measurement

Day of 

measurement

Day 1 after 

measurement

Day 2 after 

measurement

Day 3 after 

measurement

8/9/2005 10:35 42.3 45 42 38 37 36

4/27/2000 11:30 77.3 84 82 83 87 89

0

1

2

3

4

1,304

1,305

1,306

1,307

1,308

1,309

1,310

1,311

1,312

1,313

1,314

1/1/2008 4/1/2008 7/2/2008 10/1/2008 1/1/2009 4/2/2009 7/3/2009 10/2/2009

Precipitation, in inches

Altitude, in feet above North American Vertical

Datum o f 1988

Date (month/day/year)

Precipitation at station 399138

Hydraulic head at observation well A–1

Hydraulic head at observation well A–2

Elm River stage at streamgage

453430098263200

EXPLANATION

Figure 26. Comparison of precipitation, hydraulic head in Elm 

aquifer for wells A–1 and A–2, and stage in Elm River.

In general, the Elm River and Moccasin Creek were 

assumed to interact with the Elm aquifer as they cross the 

Lake Dakota Plain because the top of the Elm aquifer was 

at or near the land surface. A summary of the seasonal mean 

daily streamflow at USGS streamgage 06471770 (table 7) 

shows mean seasonal streamflow that ranged between 1.7 and 

3.8 ft3

/s.
Numerical Model of Groundwater Flow 33

Water Use

Water use from the glacial aquifer system mostly was 

from the Elm aquifer and included irrigation, municipal, and 

suburban water supplies. All of the production wells (fig. 27) 

were completed in the Elm aquifer, with the exception of a 

low-production well east of Columbia that was completed in 

the Middle James aquifer. Estimates of water use were determined on the basis of water rights permits from the South 

Dakota Department of Environment and Natural Resources 

Water Rights Program (SDDENR-WR) and pumping records 

when available. For the years when pumping records were not 

available, withdrawals were estimated on the basis of the well 

permit, correlations with existing pumping records, and examination of changes in well hydrographs. Some irrigation permits 

were for multiple well arrangements where the water was 

pumped to a central holding pond and then pumped to the irrigation system. Water use was distributed equally between these 

wells. The distribution of production wells (fig. 27) includes 

the general locations for multi-well irrigation systems.

Table 5. Lithologic log for well A–1.

[Datum is North American Vertical Datum of 1988; screened interval is from 

41 to 51 feet; U.S. Geological Survey station number 453430098262901]

Altitude 

(feet)

Depth below 

land surface 

(feet)

Description

1,312.8–1,309.8 0–3 Topsoil, black

1,309.8–1,302.8 3–10 Clay, dark-gray

1,302.8–1,297.8 10–15 Sand, brown, olive, coarse

1,297.8–1,295.8 15–17 Sand and gravel, gray 

1,295.8–1,294.8 17–18 Clay, gray 

1,294.8–1,256.8 18–56 Sand, gray, medium to coarse, 

subangular to subrounded; some 

layers of clay and coal

1,256.8–1,250.8 56–62 Clay, gray

Table 6. Lithologic log for well A–2.

[Datum is North American Vertical Datum of 1988; screened interval is from 

31.5 to 41.5 feet; U.S. Geological Survey station number 453430098264501]

Altitude 

(feet)

Depth below 

land surface 

(feet)

Description

1,312.8–1,309.8 0–3 Topsoil, black

1,309.8–1,303.8 3–9 Clay, dark-gray to gray

1,303.8–1,300.8 9–12 Clay light-gray to gray

1,300.8–1,298.8 12–14 Sand, gray

1,298.8–1,295.8 14–17 Clay, yellowish brown

1,295.8–1,287.8 17–25 Clay, yellowish brown, some sand 

and gravel

1,287.8–1,283.8 25–29 Clay, gray, sandy

1,283.8–1,275.8 29–37 Sand, gray

1,275.8–1,270.8 37–42 Sand, gray, some clay

1,270.8–1,266.8 42–46 Sand

1,266.8–1,260.8 46–52 Clay, gray, sandy

Table 7. Summary of seasonal mean daily streamflow at 

U.S. Geological Survey streamgage 06471770.

Period of record Mean daily streamflow, in cubic feet 

per second

Begin End Seasonal 

maximum

Seasonal 

minimum

Seasonal 

mean

3/1/2000 9/30/2000 3.6 1.6 2.0

3/14/2001 9/4/2001 4.8 1.6 2.5

3/22/2003 9/30/2003 3.1 1.4 2.2

3/5/2004 9/30/2004 2.9 1.5 1.9

3/6/2005 9/30/2005 2.7 1.5 1.8

3/26/2006 7/14/2006 2.4 1.3 1.7

3/11/2007 9/30/2007 7.8 1.6 2.9

3/23/2008 9/30/2008 3.3 1.3 1.7

3/19/2009 9/30/2009 6.3 1.8 3.1

3/1/2010 9/30/2010 7.1 1.7 3.6

3/16/2011 8/2/2011 7.2 2.0 3.8

The estimated water-use rate by water year ranged from 

1.0 to 2.4 ft3/s (table 8). The irrigation rate was greatest from 

WY 1980–89, followed by a decrease with the cancellation of 

an irrigation permit. The increase in water use after WY 2005 

was the result of increased municipal production.

Numerical Model of Groundwater 

Flow

The numerical model included three aquifer layers 

separated by confining layers. Layer 1 represented the Elm 

aquifer and saturated sandy units in the Lake Dakota Plain 

(grouped as Elm aquifer), layer 2 represented the Middle 

James aquifer, and layer 3 represented the Deep James aquifer, 

as described in the “Hydrogeologic Framework” section. The 

USGS finite-difference groundwater model, MODFLOW2005 (Harbaugh, 2005), was used to simulate groundwater 

flow in the glacial aquifer system. The Parameter ESTimation code (PEST) (Doherty, 2010) was used to calibrate the 

model. PEST is an open-source, public-domain software suite 

that allows model-independent parameter estimation. The 

software is accompanied by supplementary open-source and 

public-domain software suites for calibration of groundwater 

models (Doherty, 2008). This software, together with extensive documentation, can be downloaded from http://www.

pesthomepage.org/.
34 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

EXPLANATION

! Production well

4 Observation well and identifier

BN–77V

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

!

!

!

!!!!!!!!!!!! ! ! !

!

!

!!!

!!!

!!!!!!

!!!!!!!!!!!!!!!!! !

!!!!

4

4

4 4

4

4

4

4

4

4

4

BN–77N

BN–77M

BN–77L

BN–82E

BN–82K

BN–82F

BN–77V

R0–00–41

R2–00–42

R2–00–51 R0–00–45

Foot Creek

James River

Moccasin Creek

Elm River

Foot Cr

£¤281

Columbia

Westport

Aberdeen

COUNTY ROAD 16

Figure 27. Location of production wells and South Dakota Department of Environment and Natural 

Resources observation wells in model area.
Numerical Model of Groundwater Flow 35

Calibration Stress Periods

Groundwater flow was simulated with 75 variable-length 

stress periods for 35 years, beginning on October 1, 1974, 

and ending September 30, 2009 (WY 1975–2009; table 9), to 

calibrate the model. The first stress period simulated average 

input parameters for the 35-year period as a means to provide 

initial conditions representative of the long-term climate. 

Subsequent stress periods included four stress periods for 

WY 1980–82 and WY 2000–2009: October–February, 

March–April, May–June, and July–September; all other water 

years were simulated using one stress period. Water years 

1980–82 represented a dry period at the end of a 30-year 

trend of below average precipitation (fig. 2). Water years 

2000–2009 included a dry and wet period following the wet 

period in the 1990s. These stress periods were selected for 

seasonal calibration of wet and dry conditions. The other 

periods were simulated with yearly stress periods to reduce 

model run times.

Finite-Difference Grid and Boundary Conditions

The finite-difference grid consisted of 368 rows and 

410 columns with a cell size of 200 ft on a side. Model 

boundaries were represented by specified-head boundaries and 

no-flow boundaries (figs. 28–30). The northern and southern 

boundaries of model layers 1 and 2 were represented by timevariant specified-head boundaries (figs. 31–32). Layer 3 was 

assigned time-variant specified-head boundaries where aquifer 

boundaries crossed the edges of the grid, namely on the northern, eastern, and southern boundaries (fig. 33).

The land surface, stream altitudes, regional hydraulic 

heads based on the potentiometric surface prepared from water 

levels collected at wells that had long-term records (fig. 18; 

table S7–1), and observed hydraulic heads near the boundaries 

(fig. 18) were used to estimate the hydraulic head distribution 

at the boundaries for each stress period for model layer 1. The 

minimum, mean, and maximum values for all stress periods 

for model layer 1 are shown in figure 31.

Hydraulic heads near the boundaries (fig. 34) and a 

numerically simulated potentiometric surface from Emmons 

(1990) (fig. 20) were used to estimate the hydraulic head 

distribution at the boundaries for each stress period for model 

layer 2. The minimum, mean, and maximum values for all 

stress periods for model layer 2 are shown in figure 32.

Hydraulic heads near the boundaries (fig. 35) and the 

numerically simulated potentiometric surface from Emmons 

(1990) (fig. 21) were used to estimate the hydraulic head 

distribution at the boundaries for each stress period for model 

layer 3. The minimum, mean, and maximum values for all 

stress periods for model layer 3 are shown in figure 33.

The estimated potentiometric surface describing groundwater flow (fig. 18) was used to estimate the starting hydraulic heads for model layer 1. The starting hydraulic heads for 

model layers 2 and 3 were estimated on the basis of mean 

hydraulic head values (figs. 34 and 35, respectively) and 

the simulated potentiometric surfaces from Emmons (1990) 

(figs. 20–21). Water-level data for wells completed in the Elm, 

Middle James, and Deep James aquifers can be accessed at 

http://nwis.waterdata.usgs.gov/sd/nwis/gwlevels.

Table 8. Estimated water-use rates, 

for water years 1975–2009.

Water 

year

Water-use rate, 

in cubic feet per second

1975 1.0

1976 1.4

1977 1.0

1978 1.0

1979 1.1

1980 1.5

1981 1.9

1982 2.1

1983 2.0

1984 2.0

1985 2.0

1986 1.7

1987 1.8

1988 1.9

1989 1.7

1990 1.6

1991 1.6

1992 1.5

1993 1.1

1994 1.6

1995 1.8

1996 1.8

1997 1.3

1998 1.8

1999 1.8

2000 1.3

2001 1.6

2002 1.5

2003 1.5

2004 1.5

2005 1.1

2006 1.8

2007 2.0

2008 2.1

2009 2.4
36 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Table 9. Simulated stress periods, water years 1975–2009.

Stress period 

(SP)

Beginning 

date Ending date Stress length (months) 

SP1 10/01/1974 09/30/2009 420

SP2 10/01/1974 09/30/1975 12

SP3 10/01/1975 09/30/1976 12

SP4 10/01/1976 09/30/1977 12

SP5 10/01/1977 09/30/1978 12

SP6 10/01/1978 09/30/1979 12

SP7 10/01/1979 02/29/1980 5

SP8 03/01/1980 04/30/1980 2

SP9 05/01/1980 06/30/1980 2

SP10 07/01/1980 09/30/1980 3

SP11 10/01/1980 02/28/1981 5

SP12 03/01/1981 04/30/1981 2

SP13 05/01/1981 06/30/1981 2

SP14 07/01/1981 09/30/1981 3

SP15 10/01/1981 02/28/1982 5

SP16 03/01/1982 04/30/1982 2

SP17 05/01/1982 06/30/1982 2

SP18 07/01/1982 09/30/1982 3

SP19 10/01/1982 09/30/1983 12

SP20 10/01/1983 09/30/1984 12

SP21 10/01/1984 09/30/1985 12

SP22 10/01/1985 09/30/1986 12

SP23 10/01/1986 09/30/1987 12

SP24 10/01/1987 09/30/1988 12

SP25 10/01/1988 09/30/1989 12

SP26 10/01/1989 09/30/1990 12

SP27 10/01/1990 09/30/1991 12

SP28 10/01/1991 09/30/1992 12

SP29 10/01/1992 09/30/1993 12

SP30 10/01/1993 09/30/1994 12

SP31 10/01/1994 09/30/1995 12

SP32 10/01/1995 09/30/1996 12

SP33 10/01/1996 09/30/1997 12

SP34 10/01/1997 09/30/1998 12

SP35 10/01/1998 09/30/1999 12

SP36 10/01/1999 02/29/2000 5

SP37 03/01/2000 04/30/2000 2

SP38 05/01/2000 06/30/2000 2

SP39 07/01/2000 09/30/2000 3

SP40 10/01/2000 02/28/2001 5

SP41 03/01/2001 04/30/2001 2

SP42 05/01/2001 06/30/2001 2

SP43 07/01/2001 09/30/2001 3

SP44 10/01/2001 02/28/2002 5

Table 9. Simulated stress periods, water years 1975–2009.—

Continued

Stress period 

(SP)

Beginning 

date Ending date Stress length (months) 

SP45 03/01/2002 04/30/2002 2

SP46 05/01/2002 06/30/2002 2

SP47 07/01/2002 09/30/2002 3

SP48 10/01/2002 02/28/2003 5

SP49 03/01/2003 04/30/2003 2

SP50 05/01/2003 06/30/2003 2

SP51 07/01/2003 09/30/2003 3

SP52 10/01/2003 02/29/2004 5

SP53 03/01/2004 04/30/2004 2

SP54 05/01/2004 06/30/2004 2

SP55 07/01/2004 09/30/2004 3

SP56 10/01/2004 02/28/2005 5

SP57 03/01/2005 04/30/2005 2

SP58 05/01/2005 06/30/2005 2

SP59 07/01/2005 09/30/2005 3

SP60 10/01/2005 02/28/2006 5

SP61 03/01/2006 04/30/2006 2

SP62 05/01/2006 06/30/2006 2

SP63 07/01/2006 09/30/2006 3

SP64 10/01/2006 02/28/2007 5

SP65 03/01/2007 04/30/2007 2

SP66 05/01/2007 06/30/2007 2

SP67 07/01/2007 09/30/2007 3

SP68 10/01/2007 02/29/2008 5

SP69 03/01/2008 04/30/2008 2

SP70 05/01/2008 06/30/2008 2

SP71 07/01/2008 09/30/2008 3

SP72 10/01/2008 02/28/2009 5

SP73 03/01/2009 04/30/2009 2

SP74 05/01/2009 06/30/2009 2

SP75 07/01/2009 09/30/2009 3

Representation of Hydraulic Properties

Hydraulic properties of the glacial aquifer system were 

represented by parameters with values optimized by using 

parameter estimation through the PEST computer code. 

Parameter estimation relates observed measurements, such 

as hydraulic head, to model input parameters that represent 

physical properties of the simulated groundwater system. 

Solution of the parameter estimation problem involves mathematically determining the best modeled fit to the observed 

data by varying the input parameters. An approach and guidelines for application of parameter estimation to the calibration 

groundwater models are described by Hill (1998). The guidelines to using PEST for groundwater-model calibration by 
Numerical Model of Groundwater Flow 37

Base from U.S. Geological Survey digital data, 1977, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

EXPLANATION

Finite-difference grid—Uniform cell size of 200 feet, 

number is row or column number

Time-variant specified-head boundary for model layer 1

No-flow boundary for model layer 1

Elm aquifer

368

Foot Creek

James River

Moccasin Creek

Elm River

Foot Cr

£¤281

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Columbia

Westport

0

100

200

300

368

0 100 200 300 400 410 COUNTY ROAD 16

Aberdeen

Figure 28. Boundary conditions for model layer 1.
38 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Base from U.S. Geological Survey digital data, 1977, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

EXPLANATION

Finite-difference grid—Uniform cell size of 200 feet, 

number is row or column number

No-flow boundary for model layer 2

Time-variant specified-head boundary for model layer 2

Middle James aquifer

4 Well completed in Middle James aquifer and identifier R2–84–10

368

4

4

4

Foot Creek

James River

Moccasin Creek

Elm River

Foot Cr

£¤281

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Columbia

Westport

0

100

200

300

368

0 100 200 300 400 410 COUNTY ROAD 16

Aberdeen 452835098260701

R2–84–10 4540330982101

Figure 29. Boundary conditions for model layer 2.
Numerical Model of Groundwater Flow 39

Base from U.S. Geological Survey digital data, 1977, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

EXPLANATION

Finite-difference grid—Uniform cell size of 200 feet, 

number is row or column number

No-flow boundary for model layer 3

Time-variant specified-head boundary for model layer 3

Deep James aquifer

368

Foot Creek

James River

Moccasin Creek

Elm River

Foot Cr

£¤281

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Columbia

Westport

0

100

200

300

368

0 100 200 300 400 410 COUNTY ROAD 16

Aberdeen

Figure 30. Boundary conditions for model layer 3.
40 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Doherty and Hunt (2010) were used to develop the parameter 

estimation approach used in this study.

Commonly, a given number of parameters are used to 

represent zones of uniform hydraulic conductivity to minimize 

the number of parameters estimated with parameter estimation. A more flexible approach to model parameterization was 

used for representing horizontal hydraulic conductivity in 

model layer 1 because of the substantial number of observations (hydraulic head values) that could be used to constrain 

the parameter estimation.

Hydraulic conductivity for model layer 1 was simulated 

using pilot points (Doherty and others, 2010) and traditional 

piecewise-constant parameter zones. The hydraulic conductivity parameterization was grouped into nine zonations 

(fig. 36; table 10) delineated on the basis of the geology and 

landforms (fig. 5). This grouping of hydraulic conductivity is 

described here; the overall approach to the pilot-point parameterization is described below. Pilot points in zone HK1_1 

represent sediments deposited by the Elm River entering 

ancient Lake Dakota, with more gravel having been deposited 

toward the west (Leap, 1986). Pilot points in zone HK1_7 

represented the deltaic deposits from the Elm River meltwater channel that became finer to the east. Pilot points in zone 

HK1_2 represented areas with buried channel deposits of 

sand and gravel in cut and fill sequences with highly variable hydraulic connection in recessional and ground moraine. 

Pilot points in Zone HK1_3 represented the area overlain 

by the fine-grained lacustrine deposits in the Lake Dakota 

Plain on the eastern side of the model. Pilot points in zone 

HK1_6 represented the moraine northwest of the Elm River 

that included northwest to southeast lineations. Pilot points 

in zone HK1_4 represented the meltwater channels along the 

Elm River and Foot Creek.

Zone HK1_5 is a traditional piecewise-constant zone 

that represented an area along the edges of glacial moraine 

that was assumed to contain less permeable sediments than 

adjacent sand and gravels in the meltwater channels, deltaic 

deposits, and lacustrine deposits. Zone HK1_9 is a traditional 

piecewise-constant zone that represented an area on the northwestern side of the Elm River from Westport to zone HK1_7 

where the hydraulic gradient in the potentiometric surface was 

especially steep. Zone HK1_8 represented gravel pits.

Heterogeneity in zones HK1_1, HK1_2, HK1_3, HK1_6, 

and HK1_7 was represented with pilot points (fig. 36). Pilot 

points serve as surrogate parameters at which values are 

estimated in the parameter estimation process, and their 

1,280

1,290

1,300

1,310

1,320

1,330

1,340

1,350

1,360

1,370

1,380

1,390

1,400

0 50 100 150 200 250 300 350 400

Altitude, in feet above North American Vertical

Datum of 1988

Model column number (200 feet per column)

Land surface

Maximum hydraulic head

Mean hydraulic head

Minimum hydraulic head

Maximum and minimum stage for Elm River 

(streamgage 

06471500, fig. 1)

Maximum and minimum water levels for

observation well

BN–77N (fig. 27)

Time-variant specified-head for northern boundary

Time-variant specified-head for southern boundary

1,250

1,260

1,270

1,280

1,290

1,300

1,310

1,320

1,330

1,340

1,350

1,360

1,370

0 50 100 150 200 250 300 350 400

Altitude, in feet above North American Vertical

Datum of 1988

Model column number (200 feet per column)

Land surface

Maximum hydraulic head

Mean hydraulic head

Minimum hydraulic head

Maximum and minimum stage for Foot Creek 

(streamgage 06471800, 

fig. 1)

Maximum and minimum water 

levels for observation

well BN–77V (fig. 27)

EXPLANATION

EXPLANATION

Figure 31. Range in time-variant specified-head boundaries assigned for model layer 1 for all 

stress periods.
Numerical Model of Groundwater Flow 41

values are interpolated onto the modeling domain (Doherty, 

2003; Doherty and others, 2010). Kriging is the method used 

by PEST for extrapolating values of hydraulic conductivity 

estimated at the pilot points to the rest of the grid. Kriging 

assumes the parameters vary in a continuous manner from one 

pilot-point location to the next. Thus, points that are near each 

other have a certain degree of spatial correlation as would 

be expected given the proximity, but values kriged at points 

that are widely separated are more independent. PEST uses 

semivariograms to create relations between neighboring pilot 

points. A semivariogram was defined by Dunlap and Spinazola (1984) as a “graph of the variability of the difference of 

the regionalization data versus the distance between points.” 

In other words, a semivariogram is a graph of the amount by 

which two points differ, plotted against the distance between 

those points. The kriging factors used in the parameter 

estimation were created on the basis of user-supplied variograms generated with the PEST groundwater utility programs 

PPK2FAC and FAC2REAL that are explained in the PEST 

documentation (Doherty, 2008).

An exponential variogram was defined for each of the 

hydraulic conductivity zones using pilot points. The variograms for zones HK1_1, HK1_2, and HK1_6 included a 

direction and magnitude of anisotropy. When anisotropy is 

included in the variogram, the change in hydraulic conductivity between pilot points in the direction of anisotropy is 

less than between pilot points perpendicular to the direction 

of anisotropy. Zone HK1_1 was assigned anisotropy with a 

bearing 32 degrees west of north and a magnitude of 2 on the 

basis of the outwash channel orientation. Zone HK1_2 was 

assigned anisotropy with a bearing 28 degrees east of north 

and a magnitude of 1.5 on the basis of the preferential orientation of sand and gravels deposits along the margins of the 

recessional moraine, which retreated to the northwest. Zone 

HK1_6 was assigned anisotropy with a bearing 32 degrees 

west of north and a magnitude of 2 on the basis of lineations 

(Leap, 1986) and the shape of the potentiometric surface.

Each of the 359 pilot points was represented as a 

parameter in the parameter estimation. Tikhonov regularized 

inversion is an approach in PEST that uses a modeler’s softknowledge about the system to obtain a unique calibration 

from a fundamentally non-unique, highly parameterized model 

(Doherty and Hunt, 2010). The model-to-observed measurement objective function is augmented with an additional 

regularized objective function that includes prior information 

equations that quantifies the deviation of adjacent pilot point 

values from the modeler’s preferred condition. A preferredhomogeneity condition was used for regularization, which 

gives preference to calibration solutions where the difference 

between adjacent pilot points is equal to zero (Doherty and 

Hunt, 2010). This approach establishes homogeneity within 

the aquifer zone as the preferred parameter condition. The 

weight for each prior information equation was calculated on 

the basis of the kriging variograms established for each zone. 

Groundwater utility programs supplied with PEST (Doherty, 

2008) were used to develop the necessary control files for 

the parameter estimation process. In summary, this approach 

allowed heterogeneity to be in the hydraulic conductivity array 

to improve the fit between simulated and observed calibration 

targets; however, the variability added would only happen if a 

sufficient improvement in fit was obtained, and the variability 

could be constrained to hydrogeologically reasonable values 

by adjusting the tradeoff between the measurement and regularization objective function (Fienen and others, 2009).

Model layers 2 and 3 were assumed to have homogeneous horizontal hydraulic conductivity. The scant data available for these aquifers did not provide adequate information 

for zonation geometry or the use of pilot points.

The vertical hydraulic conductivity of confining layers 

was represented with one parameter representing an array 

multiplier for each entire layer, VKCB1_1 for the upper 

confining layer and VKCB2_1 for the lower confining layer. 

The confining layers were initially parameterized using the 

range in hydraulic conductivity determined for unweathered 

till from studies in counties near and surrounding Brown 

County in eastern South Dakota (table 3). Both parameters 

were assigned ranges of about 5×10-5 to 0.1 ft/d and were 

optimized by parameter estimation.

1,260

1,270

1,280

1,290

1,300

1,310

1,320

1,330

1,340

1,350

50 100 150 200 250 300 350

Land surface

Maximum hydraulic head

Mean hydraulic head

Minimum hydraulic head

Single hydraulic head

measurement from well

452835098260701 (fig. 29)

150 200 250 300 350

Altitude, in feet above North American Vertical

Datum of 1988

Altitude, in feet above North American Vertical

Datum of 1988

Model column number (200 feet per column)

Model column number (200 feet per column)

Time-variant specified-head for northern boundary

Time-variant specified-head for southern boundary

1,290

1,300

1,310

1,320

1,330

1,340

1,350

1,360

1,370

1,380

Land surface

Maximum hydraulic head

Mean hydraulic head

Minimum hydraulic head

Maximum and minimum

hydraulic head for well

R2–84–10 (fig. 29)

Single hydraulic head

measurement from

well 454033098210801 

(fig. 29)

EXPLANATION

EXPLANATION

Figure 32. Range in time-variant specified-head boundaries 

assigned for model layer 2 for all stress periods.
42 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Model column number (200 feet per column)

150 200 250 300 350

1,290

1,300

1,310

1,320

1,330

1,340

1,350

1,360

Altitude, in feet above North A

merican Vertical

Datum of 1988 

Time-variant specified-head for northern boundary

Land surface

Maximum hydraulic head

Mean hydraulic head

Minimum hydraulic head

EXPLANATION

Land surface

Maximum hydraulic head

Mean hydraulic head

Minimum hydraulic head

EXPLANATION

Land surface

Maximum hydraulic head

Mean hydraulic head

Minimum hydraulic head

EXPLANATION

Time-variant specified-head for southern boundary

Time-variant specified-head for eastern boundary

Altitude, in feet above North A

merican Vertical

Datum of 1988 

Altitude, in feet above North A

merican Vertical

Datum of 1988 1,270

1,280

1,290

1,300

1,310

1,320

1,330

1,340

Model column number (200 feet per column)

Model column number (200 feet per column)

50 100 150 200 250 300 350

1,260

1,270

1,280

1,290

1,300

1,310

1,320

1,330

0 20 40 60 80 100 120 140 160 180 200

Figure 33. Range in time-variant specified-head boundaries assigned for model layer 3 for all stress periods.
Numerical Model of Groundwater Flow 43

Well—Number is mean altitude of hydraulic head, 

in feet above North American Vertical Datum of 1988

EXPLANATION

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

! 1,275

!

!

!

!

!

!

!

! !

!

!

! !

!

£¤281

Columbia

Westport

1,267

1,289 1,276

1,285

1,296

1,298 1,272

1,300

1,297

1,275

1,275

1,270

1,276

1,301

Foot Creek

James River

Moccasin Creek

Elm River

Foot Cr

Aberdeen

COUNTY ROAD 16

Middle James

aquifer

boundary

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Figure 34. Mean hydraulic head altitudes for wells completed in the Middle James aquifer (model 

layer 2).
44 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

1,297! Well—Number is mean altitude of hydraulic head, in feet 

above North American Vertical Datum of 1988 

EXPLANATION

!

!

!

!

!

!

!!

Foot Creek

James River

Moccasin Creek

Elm River

Foot Cr

£¤281

Columbia

Westport

1,274

1,274

1,297

1,305

1,296

1,297

1,299

1,278

Aberdeen

COUNTY ROAD 16

Deep James

aquifer

boundary

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Figure 35. Mean of hydraulic head altitudes for wells completed in the Deep James aquifer (model 

layer 3).
Numerical Model of Groundwater Flow 45

EXPLANATION

! Pilot points

Hydraulic conductivity zones

HK1_1

HK1_2

HK1_3

HK1_4

HK1_5

HK1_6

HK1_7

HK1_8

HK1_9

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

)

)

! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! ! ! ! ! ! ! ! ! ! ! ! ! ! !

! !

! !

! !

! !

!!

!!!

!!

!!

!!!

! ! !

! !

! ! !

! !

!

! !

! ! !

! ! !

!

! !

! !

!

!

!

! !

!

!

!

! !

!

!

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

£¤281

45 35'

45 30'

45 40'

98 30' 98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Columbia

Westport

Aberdeen

COUNTY ROAD 16

Figure 36. Horizontal hydraulic conductivity zones for model layer 1 and location of pilot points.
46 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Representation of Water Budget Components

Recharge to model layer 1 was estimated by using the 

SWB method described in Supplement 6. Four multiplier 

parameters based on the till thickness (0–10, 10–20, 20–30, 

and greater than 30 ft) were used to optimize the SWB 

estimates during the groundwater-model calibration process 

(fig. 37). The parameter zones were the same as the till 

thickness zones used in the SWB estimate of recharge (see 

Supplement 6). The bounds for recharge multiplier parameter 

RCH_TS1 were 0.8 and 1.2, and the bounds for parameters 

RCH_TS2 and RCH_TS3 were 0.7 and 1.3, respectively. 

Recharge estimates calculated by using the SWB method 

were most uncertain for parameter RCH_TS4, which represented the area with glacial till greater than 30 ft, because this 

zone represented a large range in till thickness and plausible 

vertical hydraulic conductivity values. Parameter RCH_TS4 

was a multiplier of the SWB estimated recharge value of 

0.01 in/yr. The bounds on this parameter were set as 0.5 to 

9 to permit larger adjustments in the recharge value for this 

parameter.

Simulated evapotranspiration from model layer 1 was 

linearly decreased to an extinction depth of 6 ft. The arrays 

of potential evapotranspiration determined by using the SWB 

method (Supplement 6) were multiplied by parameter EVT1_

TS, which was optimized by using PEST during the calibration process within a specified range of 0.8 to 1.2.

Elm River and Foot Creek were represented in the model 

by using the MODFLOW River Package. The river cells were 

grouped into seven parameter zones (fig. 38) with the vertical 

conductance of the river cells optimized by parameter estimation. Vertical conductance is the vertical hydraulic conductivity multiplied by the length of the model cell and the width 

of the river, and divided by the thickness of the sediments 

separating the river and aquifer. The bounds for the vertical 

conductance parameters ranged from 0.001 to 0.1 feet squared 

per second (ft2/s) and were estimated from the calculation of 

vertical conductance for the cells where temperature (Supplement 5) was used to estimate vertical conductance (table 11; 

fig. 38).

Moccasin Creek is an intermittent stream that was represented in the model by using the MODFLOW Drain Package 

(fig. 38). Generally, in the late fall, streamflow in the stream is 

less than 1 ft3/s (table 12). The drain vertical conductance was 

assigned a value of 0.05 ft2/s.

Water use described previously was represented with the 

MODFLOW Well Package. Pumping withdrawals were averaged for each respective stress period.

Model Calibration

The numerical model was calibrated by using the PEST 

parameter estimation program to minimize the sum of the 

squared weighted residuals (“measurement objective function”) for 954 observed (measured) and simulated hydraulic 

heads. Streamflow ranges described in the “Interaction with 

Surface Water” section were used to constrain the range in 

acceptable simulated flow to or from the aquifer to streams by 

a trial and error process.

Head targets included 135 sites: 113 sites in the Elm 

aquifer, 14 sites in the Middle James aquifer, and 8 sites in 

the Deep James aquifer (fig. 39). Hydraulic heads for six 

SDDENR-WR observation wells completed in the Elm aquifer 

(BN-77L, BN-77M, BN-77V, BN-82E, BN-82F, and BN-82K; 

fig. 27), which had synoptic water-level measurements that 

spanned most of the transient simulation period, were assigned 

a weight of 1. Representative head targets were selected 

from the available data for each stress period for each of the 

six SDDENR-WR observation wells, resulting in 681 total 

calibration targets. Wells with a single water-level measurement or a small number of water-level measurements made 

during the transient simulation period totaled 273 calibration 

Table 10. Hydraulic conductivity parameter zones representing model layer 1.

Parameter 

name Parameter description

HK1_1 Outwash near mouth of Elm River at western edge of ancient Lake Dakota with heterogeneity 

approximated with pilot points.

HK1_2 Recessional and ground moraine southwest of Elm River with heterogeneity approximated with 

pilot points.

HK1_3 Lake Dakota Plain lacustrine deposits with heterogeneity approximated with pilot points.

HK1_4 Outwash channel along Elm River and Foot Creek.

HK1_5 Transition zone from glacial moraine to outwash channels, deltaic deposits, or lacustrine deposits to approximate limited connection between zones.

HK1_6 Recessional and ground moraine northeast of Elm River with heterogeneity approximated with 

pilot points.

HK1_7 Elm River outwash and delta deposits with heterogeneity approximated with pilot points.

HK1_8 Gravel pits that were assigned a high hydraulic conductivity to approximate the water bodies.

HK1_9 Transition zone on north side of Elm River where the hydraulic gradient is very steep.
Numerical Model of Groundwater Flow 47

EXPLANATION

Parameter name; till thickness, in feet

RCH_TS1; 0 to less than 10

RCH_TS2; 10 to less than 20

RCH_TS3; 20 to less than 30

RCH_TS4; 30 and greater

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

Foot Creek

James River

Moccasin Creek

Elm River

Foot Cr

£¤281

Columbia

Westport

COUNTY ROAD 16

Aberdeen

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Figure 37. Distribution of recharge parameters in model area as defined by glacial till thickness.
48 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

EXPLANATION

Site with vertical conductance estimate with

temperature site identifier

River parameter groups

RIV1_1

RIV1_2

RIV1_3

RIV1_4

RIV1_5

RIV1_6

RIV1_7

Drain parameter group

DRN1_1

!

T6

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

!

!

!

!

! !

Foot Creek

James River

Moccasin Creek

Elm River

Foot Cr

£¤281

Columbia

Westport

T9 T6

T8

T5

T7

T2

COUNTY ROAD 16

Aberdeen

Figure 38. Location of vertical conductance sites, river cell parameter groups for Elm River and Foot 

Creek, and drain cell parameter group for Moccasin Creek. 
Numerical Model of Groundwater Flow 49

targets. These hydraulic heads were assigned a weight of 2 to 

increase the importance of these targets in the calibration and 

to provide spatial balance to the objective function. Estimated average hydraulic heads for 56 wells with water-level 

measurements made before 1974 were assigned a weight of 1 

and used as a calibration target in the starting simulation of 

average conditions for WY 1975–2009.

Calibration to hydraulic head values alone often result 

in highly correlated parameters. Flow observations generally decrease the correlation between parameters (Poeter and 

Hill, 1997). The relatively small flow estimates of a few cubic 

feet per second of gain or loss described in the “Interaction 

with Surface Water” section were used to provide trial and 

error constraints on the calibration. The SWB estimates of the 

spatial and temporal distribution of fluxes for recharge and 

evapotranspiration were assumed to provide some constraint 

on these flows by maintaining the distribution and only optimizing the multiplier of these fluxes in model calibration.

The linear regression for the optimized fit (Helsel and 

Hirsch, 2002) between the simulated and observed hydraulic 

heads for all aquifers combined (fig. 40) had a coefficient 

of determination (R2; fraction of the variance explained by 

regression) of 0.94. The mean of the difference between simulated and observed values was -1.00 ft for all three aquifers 

combined, with a mean difference of -1.20 ft for the Elm 

aquifer, 0.71 ft for the Middle James aquifer, and 4.05 ft for 

the Deep James aquifer. The mean of the absolute difference 

between simulated and observed values was 4.21 ft for all 

three aquifers combined, with a mean of the absolute difference of 4.20 ft for the Elm aquifer, 5.9 ft for the Middle James 

aquifer, and 4.9 ft for the Deep James aquifer.

For individual sites in model layer 1, the mean of the 

difference between simulated and observed values was less 

than plus or minus 10 ft for 87 percent of the sites (fig. 41). 

The water-level trends for the simulated and observed hydraulic heads for the six SDDENR-WR observation wells (fig. 42) 

are similar with an average difference of less than 5 ft for 5 of 

the 6 wells. For well BN–77L, the simulated hydraulic heads 

averaged about 13 ft less than the observed hydraulic heads. 

The gradient between BN–77L and a well completed in the 

flood plain of the Elm River about 2,500 ft west (fig. 41) was 

about 35 ft. This result may be an artifact of the hydraulic 

connection between the outwash along the Elm River and the 

sands and gravels in the glacial moraine being less in this area 

than is represented in the model. The simulated potentiometric 

surface for average conditions for WY 1975–2009 shows the 

general flow direction following the topography from northwest to the southeast with a steep hydraulic gradient towards 

the Elm River in the northwestern part of the model area. The 

potentiometric surface in the Lake Dakota Plain reflects the 

flat topography as indicated by the relatively flat hydraulic 

gradient.

For sites in model layer 2, the mean of the difference 

between simulated and observed hydraulic heads was less than 

plus or minus 10 ft for 75 percent of the sites (fig. 43). The 

simulated hydraulic heads in the southeastern corner of the 

model were 10 to 23 ft above observed hydraulic heads. The 

specification of a no-flow boundary condition in this area of 

the model likely is responsible for this difference.

For sites in model layer 3, the mean of the difference between simulated and observed values was less than 

plus or minus 10 ft for 71 percent of the sites (fig. 44). The 

Table 11. Vertical conductance at selected sites near Elm River.

Temperature 

site identifier 

(fig. 23)

Adjacent 

piezometer 

identifier 

(fig. 23)

Vertical hydraulic 

conductivity 

(feet per day)

Thickness of 

sediment separating 

Elm River and Elm 

aquifer 

(feet)

River cell 

length 

(feet)

River width 

(feet)

Vertical conductance 

(feet squared per 

day)

Vertical conductance 

(feet squared per 

second)

T2 PZ8 1.00 17.8 200 90 1,010 0.012

T5 PZ1 2.48 9.9 200 70 3,510 0.041

T6 PZ3 0.14 6.8 200 120 494 0.006

T7 PZ6 1.34 6.1 200 50 2,200 0.025

T8 PZ7 0.28 11.2 200 80 400 0.005

T9 PZ9 1.62 16.1 200 100 2,010 0.023

Table 12. Streamflow measurements in the fall 

at Moccasin Creek at Aberdeen, South Dakota.

[U.S. Geological Survey streamgage 06471770]

Date Streamflow measurement, 

in cubic feet per second

11/15/1999 0.30

11/28/2000 0.45

11/13/2001 0.06

11/14/2002 0.05

12/02/2003 0.01

11/23/2004 0.23

11/10/2005 0.04

10/03/2006 0.20

10/08/2008 0.27
50 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

EXPLANATION

Well with water-level measurement

! Multiple measurements in Elm aquifer—Number is measurement count

" Multiple measurements in Middle James aquifer—Number is measurement count

# Multiple measurements in Deep James aquifer—Number is measurement count

! Single measurement in Elm aquifer

; Single measurement in Middle James aquifer

# Single measurement in Deep James aquifer

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

! !

!

!

! !! !

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

! !

! !

!

!

!

!!!

!!

!

!

!

! !

!

! ! !

! ! ! !

!

!

! ! ! ! ! ! ! !

! !! ! !

! ! ! ! ! !

! ! !

! !

! !

!

! !

!

! !

! !

!

!

!

!

!

!

"

;

;

;

;

;

;

; ;

;

;

; ;

;

#

#

#

#

#

#

##

!

Foot Creek

James River

Moccasin Creek

Elm River

Foot Cr

£¤281

Columbia

Westport

7 2

3

3

4

4

4

3

4

5

6

5

7

7 7

8

8

8

8

12

13

10

16

45

16

19

99

87

89

105

119

118

COUNTY ROAD 16

Aberdeen

Figure 39. Location of wells with water-level data used for model calibration and number of waterlevel measurements per well.
Numerical Model of Groundwater Flow 51

simulated hydraulic heads at two sites were 19 ft higher than 

observed hydraulic heads. Because of the lack of test holes 

that fully penetrate the Deep James aquifer, the boundaries are approximate, which in turn can affect the simulated 

hydraulic heads.

Calibrated Parameters

Calibrated values were determined for hydraulic conductivity, streambed conductance, recharge rates, and evapotranspiration rates (table 13). Because of the limited flow 

constraints used in model calibration, alternate combinations 

of calibrated values also could produce an acceptable fit to the 

measured data.

Horizontal hydraulic conductivity values for model 

layer 1 ranged from 2 to 500 ft/d with a mean of 94 ft/d 

(table 13; fig. 45). Zone HK1_8 represented sand pits that 

were assigned a high horizontal hydraulic conductivity value 

of 1,728 ft/d. The areas with the highest hydraulic conductivity 

were outwash channels along the Elm River and Foot Creek. 

Zone HK1_6 included an area northeast of the Elm River with 

horizontal hydraulic conductivity values that ranged from 250 

to 300 ft/d. Horizontal hydraulic conductivity values for model 

layers 2 and 3 were 41 and 30 ft/d, respectively.

Vertical hydraulic conductivity values were 0.0002 ft/d 

for confining layer 1 and 0.0003 ft/d for confining layer 2. 

Specific yield for model layer 1 was 0.1, and specific storage 

was 0.0005 per foot. Specific storage for model layers 2 

and 3 were 0.0004 and 0.0003 per foot,respectively. Vertical conductance of the sediments separating the Elm River 

and Elm aquifer ranged from 87 to 4,320 ft2

/d. Calibrated 

mean recharge rates ranged from 2.5 in/yr where the glacial 

till thickness was less than 10 ft to 0.8 in/yr where glacial till 

thickness was greater than 30 ft. The calibrated mean annual 

evapotranspiration rate was 8.8 in/yr (table 13).

1,260

1,280

1,300

1,320

1,340

1,360

1,380

1,260 1,280 1,300 1,320 1,340 1,360 1,380

Simulated hydraulic head, in feet above North American

Vertical Datum of 1988 

Observed hydraulic head, in feet above North American

Vertical Datum of 1988

Elm aquifer

Middle James aquifer

Deep James aquifer

Coefficient of determination 

(R2

) = 0.94 

EXPLANATION

Figure 40. Linear regression between simulated and 

observed hydraulic heads for all aquifers.

Table 13. Calibrated values for model parameters.

[--, not applicable]

Parameter 

name

Minimum 

parameter 

value

Mean 

parameter 

value

Maximum 

parameter 

value

Horizontal hydraulic conductivity, in feet per day 

(see fig. 36 for location of hydraulic conductivity zones)

HK1_1 121 197 382

HK1_2 25 97 52

HK1_3 62 89 141

HK1_4 -- 500 --

HK1_5 -- 9 --

HK1_6 56 200 300

HK1_7 30 57 78

HK1_8 -- 1,728 --

HK1_9 -- 2 --

HK2_1 -- 41 --

HK3_1 -- 30 --

Vertical hydraulic conductivity, in feet per day

VKA1_1 -- 1.0 --

VKA2_1 -- 1.0 --

VKA3_1 -- 1.0 --

VKCB1_1 -- 0.0002 --

VKCB2_1 -- 0.0003 --

Specific yield

SY1_1 -- 0.1 --

Specific storage, in per foot

SS1_1 -- 0.0005 --

SS2_1 -- 0.0004 --

SS3_1 -- 0.0003 --

Vertical conductance of sediments separating streams and 

Elm aquifer, in feet squared per day 

(see fig. 38 for location of stream reach)

RIV1_1 -- 1,378 --

RIV1_2 -- 229 --

RIV1_3 -- 845 --

RIV1_4 -- 1,260 --

RIV1_5 -- 91 --

RIV1_6 -- 87 --

RIV1_7 -- 740 --

DRN1_1 -- 4,320 --

Recharge rate for average condition simulation for water 

years 1975–2009, in inches per water year 

(see fig. 37 for location of recharge zones)

RCH_TS1 -- 2.5 --

RCH_TS2 -- 2.0 --

RCH_TS3 -- 1.7 --

RCH_TS4 -- 0.8 --

Mean annual evapotranspiration rate, in inches per water year

EVT1_TS -- 8.8 --
52 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

EXPLANATION

Hydraulic head difference, in feet

! -14 to -10

! Greater than -10 to -5

! Greater than -5 to 0

! Greater than 0 to 5

! Greater than 5 to 10

! Greater than 10 to 25

Long-term observation well with site identifier

Simulated average potentiometric surface (water years 1975–2009) for

model layer 1—Number is hydraulic head, in feet above North American 

Vertical Datum of 1988. Contour interval 10 feet

Groundwater flow direction

1,300

( BN–77V

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

(

(

(

(

(

(

!

!

!

!

!

!

!

!

! !

!

!

!

!

!

!

!!

!

!

!!!!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

! !

! !

!

!

!

!!!

!!

!

!

!

! !

!

! ! !

! ! ! !

!!

! ! ! ! ! ! ! !

! ! !! !

! ! !

! !

!

! ! !

! !

! !

!

! !

!

! !

! !

!

!

!

!

!

!

Foot Creek

James River

Moccasin Creek

Elm River

Foot Cr

£¤281

1,310

1,300 1,310

1,320

1,300

1,320

1,330

1,3501,340

1,360

1,370

1,290

1,280

1,300

1,290

1,290

1,340

1,330

1,350

1,370

1,310

1,300 1,310

1,320

1,300

1,320

1,330

1,350

1,340

1,360

1,370

1,290

1,280

1,300

1,290

1,340

1,330

1,350

1,370

1,290

Columbia

Westport

BN–82K

BN–82F

BN–82E BN-82E

BN–77V

BN–77M

BN–77L

1,280

COUNTY ROAD 16

Aberdeen

Elm aquifer

boundary

Figure 41. Simulated potentiometric surface for average conditions for water years 1975–2009 and 

mean difference between simulated and observed transient hydraulic heads for model layer 1.
Numerical Model of Groundwater Flow 53

1,300

1,310

1,320

1,330

1,340

1,350

1,360

Hydraulic head, in feet above North American

Vertical Datum of 1988 

Hydraulic head, in feet above North American

Vertical Datum of 1988 

Hydraulic head, in feet above North American

Vertical Datum of 1988 

1970 1980 1990 2000 2010

Simulated

Observed

EXPLANATION

Simulated

Observed

EXPLANATION

Simulated

Observed

EXPLANATION

Well BN–77L

Well BN–77M

Well BN–77V

Calendar year

Calendar year

1,300

1,310

1,320

1,330

1,340

1,350

1,360

1970 1980 1990 2000 2010

1,270

1,280

1,290

1,300

1,310

1,320

1,330

1970 1980 1990 2000 2010

Calendar year

Hydraulic head, in feet above North American

Vertical Datum of 1988 

Hydraulic head, in feet above North American

Vertical Datum of 1988 

Hydraulic head, in feet above North American

Vertical Datum of 1988 

Simulated

Observed

EXPLANATION

Simulated

Observed

EXPLANATION

Simulated

Observed

EXPLANATION

Well BN–82E

Well BN–82F

Well BN–82K

Calendar year

Calendar year

Calendar year

1,330

1,340

1,350

1,360

1,370

1,380

1,390

1970 1980 1990 2000 2010

1,270

1,280

1,290

1,300

1,310

1,320

1,330

1970 1980 1990 2000 2010

1970 1980 1990 2000 2010

1,270

1,280

1,290

1,300

1,310

1,320

1,330

Figure 42. Simulated and observed hydraulic heads for model layer 1 for long-term observation wells.
54 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

EXPLANATION

! Well—Number is hydraulic head difference, in feet

Simulated average potentiometric surface (water years 1975–2009) 

for model layer 2—Number is hydraulic head, in feet above North 

American Vertical Datum of 1988. Contour interval 10 feet

1,300

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

!

!

!

!

!

!

!

! !

!

!

! !

!

Foot Creek

James River

Moccasin Creek

Elm River

Foot Cr

£¤281

1,300

1,280

1,310

1,290

1,320

1,330

1,310

Columbia

Westport

0

8

0

4

2

2

23

-7 10

-4

10 16

-2

-16

COUNTY ROAD 16

Aberdeen

Middle James

aquifer

boundary

Figure 43. Simulated potentiometric surface of average conditions for water years 1975–2009 and 

mean difference between simulated and observed transient hydraulic heads for model layer 2.
Numerical Model of Groundwater Flow 55

Figure 44. Simulated potentiometric surface of average conditions for water years 1975–2009 and mean 

difference between simulated and observed transient hydraulic heads for model layer 3.

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

EXPLANATION

! Well—Number is hydraulic head difference, in feet

Simulated average potentiometric surface (water years 1975–2009) 

for model layer 3—Number is hydraulic head, in feet above North 

American Vertical Datum of 1988. Contour interval 10 feet

1,300

T. 123 N.

T. 124 N.

T. 125 N.

R. 64 W. R. 63 W. R. 62 W.

45 35'

45 30'

98 30'

45 40'

98 22'30''

!

!

!

!

!

!

!!

Foot Creek

James River

Moccasin Creek

Elm River

Foot Cr

£¤281

1,300

1,290

1,280

1,290

1,300

1,290

1,300

Columbia

Westport

1

1

4

19

19

-2

-3

-3

Aberdeen

COUNTY ROAD 16

Deep James

aquifer

boundary
56 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

EXPLANATION

Horizontal hydraulic conductivity, in feet per day

2 to 50

Greater than 50 to 100

Greater than 100 to 150

Greater than 150 to 200

Greater than 200 to 250

Greater than 250 to 300

500

1,728

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

45 35'

45 30'

98 30'

45 40'

98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

£¤281

COUNTY ROAD 16

Columbia

Westport Elm River

Foot Creek

Moccasin Creek

Foot Cr

James River

Aberdeen

Elm aquifer

boundary

Figure 45. Calibrated horizontal hydraulic conductivity distribution for model layer 1.
Numerical Model of Groundwater Flow 57

Simulated Water Budget Components

Recharge and evapotranspiration were the largest components in the simulated water budgets (table 14). Recharge rates 

by water year ranged from 0.2 to 54.6 ft3/s, and evapotranspiration rates ranged from 4.4 to 34.3 ft3

/s (fig. 46). Changes in 

evapotranspiration follow changes in recharge with a dampened response. The general direction of groundwater flow is 

toward the Lake Dakota Plain where the overlying impermeable sediments are relatively thin, and evapotranspiration 

increases substantially when the water level moves above the 

evapotranspiration extinction depth of 6 ft.

Recharge was optimized by using PEST during model 

calibration from the SWB estimates through multiplier 

parameters RCH_TS1, RCH_TS2, RCH_TS3, and RCH_TS4 

(table 15), as described in the “Representation of Water 

Budget Components” section. On the basis of interpolated 

till thickness, parameters RCH_TS2 and RCH_TS3 were tied 

together during calibration with a potential factor range in 

multiplier of 0.7 to 1.3. A large increase in the recharge rate 

to zone RCH_TS4, as needed during model calibration, was 

considered reasonable because the rate estimated by using the 

SWB method of 0.01 in/yr was small.

The simulated net groundwater discharge to the Elm 

River from the Elm aquifer was 3.1 ft3

/s. Elm River reaches 

RIV1_1– RIV1_3 (fig. 38), which are incised in the glacial 

moraine landform, received discharge from the Elm aquifer 

with a mean discharge of 2.4 ft3/s that ranged from 1.7 to 

3.7 ft3/s by water year (fig. 47). The Elm River reach RIV1_4 

(fig. 38), which includes the reservoir upstream from Ordway 

Dam, received discharge from the Elm aquifer with a mean 

discharge of 0.6 ft3/s that ranged from 0.0 to 1.0 ft3/s by water 

year (fig. 47). These estimates seem plausible on the basis 

of the streamflow records described in the “Interaction with 

Surface Water” section. Elm River reach RIV1_5 (fig. 38), 

which extends from Ordway Dam across the Lake Dakota 

Plain to the James River, generally lost streamflow to the Elm 

aquifer with a mean streamflow loss of 0.7 ft3/s that ranged 

from 0.3 to 1.6 ft3/s by water year (fig. 47).

The Elm aquifer had small discharges to and gains from 

Foot Creek that ranged from a loss of 0.6 ft3/s to a gain of 

0.4 ft3/s by water year, with a mean value of about zero. The 

Table 14. Simulated water budgets for water years 1975–2009 (average conditions), water year 1976, and water year 1998.

[Budget component rates in cubic feet per second]

Model layer Budget component

Average conditions

(water years 

1975–2009)

Water year 1976 Water year 1998

1 Inflow Constant head 2.9 3.5 2.9

Recharge 21.5 2.6 28.4

From streams 0.6 1.1 0.8

From layer 2 0.1 0.2 0.1

Outflow Constant head 3.3 2.3 3.0

Evapotranspiration 16.0 7.3 20.5

To streams 3.7 2.4 4.5

Wells 1.3 1.8 1.8

To layer 2 0.8 0.7 0.8

Change in storage 0.0 -7.1 1.6

2 Inflow Constant head 0.4 0.4 0.4

From layer 1 0.8 0.7 0.8

From layer 3 0.1 0.1 0.1

Outflow Constant head 1.0 0.7 0.9

To layer 1 0.1 0.2 0.1

To layer 3 0.2 0.1 0.2

Change in storage 0.0 -0.1 0.1

3 Inflow Constant head 0.1 0.1 0.1

From layer 2 0.1 0.1 0.1

Outflow Constant head 0.1 0.2 0.1

To layer 2 0.1 0.1 0.1

Change in storage 0.0 -0.1 0.0
58 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Elm aquifer discharged to Moccasin Creek with a mean value 

of 0.5 ft3/s that ranged from 0.0 to 2.1 ft3/s by water year. 

These values were within a plausible range on the basis of 

the seasonal streamflow records for U.S. Geological Survey 

streamgage 06471770 (table 7).

Model Limitations

The model is a mathematical approximation of the real 

system that is limited by several simplifying assumptions. In 

a glacial aquifer system, the deposition of sands and gravels 

within glacial sediments is heterogeneous, and the calibrated 

properties in the model represent a generalized bulk approximation. The cell size of 200 ft and calibration techniques used 

in this model permit the representation of some heterogeneity; 

however, the regularization used in this parameter estimation 

only allows heterogeneity to be expressed when observed data 

support it. Given the large areas not characterized by field 

data, the real hydrologic properties at individual sites could 

vary widely from those represented in the model.

Some information was available to characterize the 

hydraulic conductivity distribution in the Elm aquifer; 

however, aquifer tests only represented a small part of model 

area. Each cell represented a bulk average hydraulic conductivity for an area of 4,000 square feet (ft2

). Lithologic information indicated that the hydraulic connection between sand and 

gravel deposits could be poor in many locations; therefore, the 

assumption that the aquifer was a continuous porous medium 

may limit the ability of the model to simulate local stresses. 

Information to characterize the Middle James and Deep James 

aquifers was sparse, and as a result the representation of 

hydraulic properties was generalized.

Vertical hydraulic conductivity estimates for glacial 

till can vary over several orders of magnitude; therefore, the 

representation of the vertical hydraulic properties of confining layers is consistent with a general approximation of the 

regional system. Similarly, the representation of the hydraulic 

connection between streams and the Elm aquifer was approximate and could vary more widely at a local level. Estimates 

of recharge and evapotranspiration also were dependent on 

estimates of the vertical hydraulic properties of the glacial till.

Application of the SWB method improved estimates of 

the spatial and temporal distribution of recharge and evapotranspiration; however, the representation of the input parameters for the analysis included bulk approximation of many 

of the input parameters. Numerous wetlands and depressions 

exist in the model area, and the potential for localized infiltration for some of these areas could be underestimated.

Calibrated values for recharge and hydraulic properties 

may be non-unique because the flow constraints on calibration were only represented by plausible ranges. Additional 

combinations of recharge and hydraulic properties also could 

produce a reasonable fit to measured hydraulic heads. Calibration of the model to hydraulic heads constrains the ratio 

between the two parameters better than the magnitude of the 

values.

Boundary conditions were estimated on the basis of 

sparse information. The time-variant specified-head boundaries on the northern and southern model boundaries were estimated on the basis of regional hydraulic heads with only a few 

actual measurements of hydraulic head at the boundaries. The 

Recharge

Evapotranspiration

EXPLANATION

0

10

20

30

40

50

60

1970 1975 1980 1985 1990 1995 2000 2005 2010

Rate, in cubic feet per second

Water year

Figure 46. Simulated recharge and evapotranspiration rates 

by water year.

Table 15. Recharge parameter boundaries and calibrated 

multiplier values.

Parameter 

name 

(fig. 35)

Minimum 

parameter 

value

Maximum 

parameter 

value

Calibrated 

parameter 

value

RCH_TS1 0.8 1.2 0.8

RCH_TS2 0.7 1.3 0.742

RCH_TS3 0.7 1.3 0.742

RCH_TS4 0.5 9.0 8.19

1970 1975 1980 1985 1990 1995 2000 2005 2010

-5

-4

-3

-2

-1

0

1

2

3

4

5

Water year

RIV1_1–RIV1_3

RIV1_4

RIV1_5

River reach (fig. 38)

EXPLANATION

Groundwater gain (+) or loss (-) from streamflow,

in cubic feet per second

Figure 47. Simulated gain or loss of groundwater in the Elm 

aquifer along the Elm River. 
Summary 59

boundaries were selected to minimize effects of stresses on the 

simulation in the areas where future development is anticipated. The approximate boundaries could have more effects 

when simulating larger stresses and longer periods of time.

The model provides a useful tool to better understand the 

potential effects of stresses; however, the numerous simplifying assumptions warrant consideration when evaluating 

management alternatives by using the model. Additional data 

from the specific area of interest with associated analysis of 

the local properties will reduce uncertainty in predictions of 

system response to specific management alternatives.

Summary

The city of Aberdeen, South Dakota, is developing plans 

and strategies for a sustainable supply of municipal water 

with a long-term plan of utilizing a balance of groundwater 

and surface-water sources. A primary source of surface water 

for Aberdeen is the Elm River. Groundwater from the Elm 

aquifer, a shallow glacial aquifer, is used as a supplemental water source in the Aberdeen area. Periodic drought and 

potential future increases in water use have raised concerns 

about declining flows in the Elm River and about water-level 

declines in the small storage reservoirs and the Elm aquifer. To 

address these concerns, the U.S. Geological Survey, in cooperation with the city of Aberdeen, developed conceptual and 

numerical models of a glacial aquifer system north of Aberdeen to provide scientific information that will be useful in 

evaluating and managing the water resources near Aberdeen.

Average annual precipitation in the model area for water 

year (WY) 1931 to WY 2009 was 19.6 inches per year (in/yr). 

The major land use in the model area is for agriculture. The 

most permeable deposits in the 490-square-mile study area, 

located in the west-central part of Brown County north of 

Aberdeen, include glacial outwash consisting of sorted gravel, 

sand, and silt. The outwash deposits within glacial deposits ranged in altitude from 1,400 to 950 feet (ft) and were 

grouped as the Elm, Middle James, and Deep James aquifers. 

The Deep James aquifer is contained within a system of 

ancient river channels.

Recharge to the Elm aquifer is by infiltration of precipitation through overlying outwash, lake sediments, and glacial 

till. Recharge and discharge to the Middle James and Deep 

James aquifers primarily is from hydraulic connection to 

overlying aquifers. Discharge from the Elm aquifer primarily 

is evapotranspiration and discharge to streams.

The Elm aquifer ranged in thickness from less than 1 

to about 95 ft, with an average thickness of about 24 ft; the 

Middle James aquifer ranged in thickness from less than 1 to 

91 ft, with an average thickness of 13 ft; and the Deep James 

aquifer ranged in thickness from less than 1 to 165 ft, with an 

average thickness of 23 ft. The confining units between the 

aquifers consisting of glacial till ranged in thickness from 0 to 

280 ft. The general direction of water movement in the model 

area in the Elm aquifer is from northwest to southeast and 

toward the Elm River and Foot Creek generally following the 

topography. Groundwater flow in the Middle James aquifer is 

to the southeast. Sparse data indicated a relatively flat potentiometric surface in the model area for the Deep James aquifer.

Glacial outwash that consists of mostly sand and gravel 

may have hydraulic conductivities of as much as several 

hundred feet per day (ft/d), and glacial till may have hydraulic 

conductivities several orders of magnitude less than 1 ft/d. A 

horizontal hydraulic conductivity of 418 ft/d and a confined 

storage coefficient of 2.4×10-5 were determined for a simulated 

6.5-day aquifer test of a sand pit in the Elm aquifer. Horizontal 

hydraulic conductivity for the Elm aquifer, determined from 

analysis of data from seven single-well tests at production 

wells for a 12-hour period, averaged 143 ft/d with a range of 

97–205 ft/d. Estimates of the vertical hydraulic conductivity of 

the sediments separating the Elm River from the Elm aquifer 

at six sites, determined from the analysis of temperature gradients, ranged from 0.14 to 2.48 ft/d.

The annual recharge for the model area, calculated 

by using a soil-water-balance method for WY 1975–2009, 

ranged from 0.028 inch in WY 1980 to 4.52 inches in 

WY 1986, with a mean of 1.56 inches. The annual potential 

evapotranspiration, calculated by using the soil-water-balance 

method, ranged from 21.8 inches in WY 1983 to 27.0 inches 

in WY 1985, with a mean of 24.6 inches. Interaction between 

the Elm aquifer and surface water happens where intervening 

glacial till is absent or thin. Water use from the glacial aquifer 

system primarily is from the Elm aquifer for irrigation, 

municipal, and suburban water supplies, and the annual water 

use rate ranged from 1.0 to 2.4 cubic feet per second (ft3/s).

The MODFLOW-2005 numerical model represented the 

Elm aquifer and saturated sandy units within the Lake Dakota 

Plain physiographic division, the Middle James aquifer, and 

the Deep James aquifer as three model layers (layers 1–3, 

respectively) that were separated by confining layers. 

Groundwater flow was simulated with 75 stress periods of 

representative lengths for 35 years beginning October 1, 1974 

(WY 1975), and ending September 30, 2009 (WY 2009), 

with the first stress period representing average conditions 

for WY 1975–2009. The finite-difference grid consisted of 

368 rows and 410 columns, with a cell size of 200 ft on a 

side. Model boundaries were represented by specified-head 

boundaries and no-flow boundaries. Properties of the glacial 

aquifer system were represented by parameters with values 

optimized by using the parameter estimation code (PEST). 

The model was calibrated by focusing on minimizing the 

difference between 954 simulated and observed hydraulic 

heads for 135 sites: 113 sites in the Elm aquifer, 14 sites 

in the Middle James aquifer, and 8 sites in the Deep James 

aquifer. The mean of the difference between observed and 

simulated hydraulic heads was -1.00 ft for all three aquifers combined, with means of -1.20 ft for the Elm aquifer, 

0.71 ft for the Middle James aquifer, and 4.05 ft for the Deep 

James aquifer. The mean of the absolute difference between 

simulated and observed hydraulic heads was 4.21 ft for all 
60 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

three aquifers combined, with a means of 4.20 ft for the Elm 

aquifer, 5.9 ft for the Middle James aquifer, and 4.9 ft for the 

Deep James aquifer.

Calibrated horizontal hydraulic conductivity values 

for model layer 1 ranged from 2 to 500 ft/d, with a mean 

of 94 ft/d. Horizontal hydraulic conductivity for model 

layers 2 and 3 were 41 and 30 ft/d, respectively. Vertical 

hydraulic conductivity was 0.0002 ft/d for confining layer 

1 and 0.0003 ft/d for confining layer 2. Specific yield for 

model layer 1 was 0.1, and specific storage was 0.0005 per 

foot. Specific storage for model layers 2 and 3 was 0.0004 

and 0.0003 per foot, respectively. Vertical conductance of 

the sediments separating the Elm River and Elm aquifer 

ranged from 87 to 4,320 feet squared per day. Calibrated 

mean recharge rates ranged from 2.5 in/yr where glacial till 

thickness was less than 10 ft to 0.8 in/yr where glacial till 

thickness was greater than 30 ft. The calibrated mean annual 

evapotranspiration rate was 8.8 in/yr. Recharge rates by water 

year ranged from 0.2 to 54.6 ft3

/s, and evapotranspiration 

rates ranged from 4.4 to 34.3 ft3/s. The simulated net streamflow gain from model layer 1 was 3.1 ft3

/s.

References Cited

Burger, H.R., Sheehan, A.F., and Jones, C.H., 2006, Introduction to applied geophysics: New York, W. W. Norton and 

Company, Inc., 554 p.

Canadell, J., Jackson, R.B., Ehleringer, J.R., Mooney, H.A., 

Sala, O.E., and Schulze, E.D., 1996, Maximum rooting 

depth of vegetation types at the global scale: Oecologia, 

v. 108, p. 583–595, accessed January 20, 2011, at http://

www.biology.duke.edu/jackson/oecol96d.pdf.

Constantz, J., and Stonestrom, D.A., 2003, Heat as a tracer 

of water movement near streams, chap. 1 of Constantz, J., 

and Stonestrom, D.A., eds., Heat as a tool for studying the 

movement of ground water near streams: U.S. Geological 

Survey Circular 1260, p. 2–6. (Also available at http://pubs.

usgs.gov/circ/2003/circ1260/.)

Cowman, T.C., 1996, Methodology and results of in-situ permeability tests in unweathered glacial till of South Dakota: 

South Dakota Geological Survey Open-File Report 3–BAS, 

20 p. (Also available at http://www.sdgs.usd.edu/pubs/pdf/

BAS-03.pdf.)

Cravens, S.J., and Ruedisili, L.C., 1987, Water movement in 

till of east-central South Dakota: Ground Water, v. 25, no. 5, 

p. 555–561.

Curve Number Work Group, 2004, Hydrologic soil-cover 

complexes, chap. 9 of National engineering handbook—Part 

630 Hydrology: U.S. Department of Agriculture, Natural 

Resources Conservation Service/Agricultural Research 

Service (210-VI-NEH), 20 p.

Davis, R.K., Iles, D.L., Schaeffer, V.R., Kortran, J.M., 

Koch, Bill, and Peterson, E.W., 1997, Hydrogeology and 

hydrochemistry of clayey till at the Sioux Falls landfill, 

Sioux Falls, South Dakota: South Dakota Geological Survey 

Open-File Report 9–BAS, 193 p. (Also available at http://

www.sdgs.usd.edu/pubs/pdf/BAS-09.pdf)

Doherty, J., 2005, PEST—Model-independent parameter 

estimation user manual (5th ed.): Watermark Numerical 

Computing, variously paged, accessed June 28, 2011, at 

http://www.pesthomepage.org/files/pestman.pdf.

Doherty, J., 2008, Groundwater data utilities: Brisbane, Australia, Watermark Numerical Computing. (Also available at 

http://pesthomepage.org/Downloads.php.)

Doherty, J., 2010, PEST, Model-independent parameter 

estimation—User manual (5th ed., with slight additions): 

Brisbane, Australia, Watermark Numerical Computing.

Doherty, J.E., Fienen, M.N., and Hunt, R.J., 2010, Approaches 

to highly parameterized inversion—Pilot-point theory, 

guidelines, and research directions: U.S. Geological Survey 

Scientific Investigations Report 2010–5168, 36 p. (Also 

available at http://pubs.usgs.gov/sir/2010/5168/.)

Doherty, J.E., and Hunt, R.J., 2010, Approaches to highly 

parameterized inversion—A guide to using PEST for 

groundwater-model calibration: U.S. Geological Survey 

Scientific Investigations Report 2010–5169, 59 p. (Also 

available at http://pubs.usgs.gov/sir/2010/5169/.)

Dunlap, L.E., and Spinazola, J.M., 1984, Interpolating watertable altitudes in west-central Kansas using kriging techniques: U.S. Geological Survey Water-Supply Paper 2238, 

19 p., accessed July 8, 2010, at http://pubs.usgs.gov/

wsp/2238/report.pdf. 

Emmons, P.J., 1987, Preliminary assessment of potential well 

yields and the potential for artificial recharge of the Elm and 

Middle James aquifers in the Aberdeen area, South Dakota: 

U.S. Geological Survey Water-Resources Investigations 

Report 87–4017, 33 p. (Also available at http://pubs.usgs.

gov/wri/1987/4017/report.pdf.)

Emmons, P.J., 1988, A digital simulation of the glacialaquifer system in Sanborn and parts of Beadle, Miner, 

Hanson, Davison, and Jerauld Counties, South Dakota: 

U.S. Geological Survey Water-Resources Investigations 

Report 87–4082, 59 p. (Also available at http://pubs.usgs.

gov/wri/1987/4082/report.pdf.)

Emmons, P.J., 1990, A digital simulation of the glacial-aquifer 

system in the northern three-fourths of Brown County, 

South Dakota: U.S. Geological Survey Water-Resources 

Investigations Report 88–4198, 74 p. (Also available at 

http://pubs.usgs.gov/wri/1988/4198/report.pdf.)
References Cited 61

Fienen, M.N., Muffles, C.T., and Hunt, R.J., 2009, On constraining pilot point calibration with regularization in PEST: 

Ground Water, v. 47, no. 6, p. 835–844, doi: 10.1111/j.1745-

6584.2009.00579.x.

Flint, R.F., 1955, Pleistocene geology of eastern South 

Dakota: U.S. Geological Survey Professional Paper 262, 

173 p., accessed November 12, 2009, at http://pubs.usgs.

gov/pp/0262/report.pdf.

Freeze, R.A., and Cherry, J.A., 1979, Groundwater: Englewood Cliffs, N.J., Prentice-Hall, Inc., 604 p.

Geophex, Ltd., 2004, GEM-2 operation manual version 3.8: Raleigh, N.C., Geophex, Ltd., 22 p., accessed 

March 8, 2012, at http://www.geophex.com/Downloads.

html.

Harbaugh, A.W., 2005, MODFLOW-2005, The U.S. Geological Survey modular ground-water model—The groundwater flow process: U.S. Geological Survey Techniques 

and Methods, book 6, chap. A16, variously paged. (Also 

available at http://pubs.usgs.gov/tm/2005/tm6A16/.)

Helsel, D.R., and Hirsch, R.M., 2002, Statistical methods in 

water resources: U.S. Geological Survey Techniques of 

Water-Resources Investigations, book 4, chap. A3, 522 p.

Hill, M.C., 1998, Methods and guidelines for effective model 

calibration: U.S Geological Survey Water-Resources Investigations Report 98–4005, 90 p.

Huang, H., and Won, I.J., 2003, Real-time resistivity sounding using a handheld broadband electromagnetic sensor:

Geophysics, v. 68, no. 4, p. 1,224–1,231.

Kress, W.H., Ball, L.B., Teeple, A.P., and Turco, M.J., 2006, 

Two-dimensional direct-current resistivity survey to supplement borehole data in ground-water models of the former 

Blaine Naval Ammunition Depot, Hastings, Nebraska, September 2003: U.S. Geological Survey Data Series 172, 31 p. 

(Also available at http://pubs.usgs.gov/ds/ds172/.)

Koch, N.C., and Bradford, W., 1976, Geology and water 

resources of Brown County, South Dakota, Part 2—Water 

resources: South Dakota Geological Survey Bulletin 25, 

53 p. (Also available at http://www.sdgs.usd.edu/pubs/

pdf/B-25(2).pdf.)

Lapham, W.W., 1989, Use of temperature profiles beneath 

streams to determine rates of vertical ground-water flow 

and vertical hydraulic conductivity: U.S. Geological Survey 

Water-Supply Paper 2337, 35 p. (Also available at http://

pubs.usgs.gov/wsp/2337/report.pdf.)

Leap, D.L., 1986, Geology and water resources of Brown 

County, South Dakota, Part I—Geology: South Dakota 

Geological Survey Bulletin 25, 48 p. (Also available at 

http://www.sdgs.usd.edu/pubs/pdf/B-25(1).pdf.)

Levenberg, K., 1944, A method for the solution of certain 

non-linear problems in least squares: Quarterly of Applied 

Mathematics, v. 2, p. 164–168.

Loke, M.H., 1999, Electrical imaging surveys for environmental and engineering studies—A practical guide to 

2-D and 3-D surveys: Geometrics, Inc., 57 p., accessed 

March 8, 2012, at ftp://geom.geometrics.com/pub/

GeoElectric/Literature/Lokenote.pdf.

Loke, M.H., 2010, RES2DINV version 3.59—Rapid 2-D 

resistivity and IP inversion using the least-squares method: 

Geoelectrical Imaging 2-D and 3-D, Geotomo Software, 148 p., accessed March 29, 2011, at http://www.

geoelectrical.com.

Lucius, J.E., Langer, W.H., and Ellefsen, K.J., 2007, An introduction to using surface geophysics to characterize sand 

and gravel deposits: U.S. Geological Survey Circular 1310, 

33 p., accessed November 13, 2008, at http://pubs.usgs.gov/

circ/2007/1310/.

Mace, R.E., 2001, Estimating transmissivity using specificcapacity data: Austin, Tex., University of Texas at Austin, 

Bureau of Economic Geology, Geological Circular 01–2, 

44 p.

Marquardt, D.W., 1963, An algorithm for least-squares estimation of nonlinear parameters: Journal of the Society for 

Industrial and Applied Mathematics, v. 11, no. 2, p. 431–

441.

McNeill, J.D., 1980, Electrical conductivity of soils and rocks: 

Ontario, Canada, Geonics, Ltd., Technical Note TN-5, 22 p.

Multi-Resolution Land Characteristics Consortium, 2011, 

National land cover database—Conterminous United 

States NLCD 2006 land cover, 30-m data, accessed January 14, 2011, at http://www.mrlc.gov/nlcd2006_downloads.

php.

National Climate Data Center, 2011, Record of climatological 

observations: National Climatic Data Center, accessed January 13, 2011, at http://www.ncdc.noaa.gov/oa/ncdc.html.

Natural Resources Conservation Service, 2009a, Physical soil 

properties—Brown County, South Dakota: U.S. Department 

of Agriculture, Natural Resources Conservation Service, 

tabular data version 13, 54 p., accessed January 13, 2011, at 

http://soildatamart.nrcs.usda.gov/State.aspx?State=SD.

Natural Resources Conservation Service, 2009b, Water 

features—Brown County, South Dakota: U.S. Department 

of Agriculture, Natural Resources Conservation Service, 

tabular data version 13, 53 p., accessed January 13, 2011, at 

http://soildatamart.nrcs.usda.gov/State.aspx?State=SD.

Poeter, E.P., and Hill, M.C., 1997, Inverse methods—A necessary next step in ground-water modeling: Ground Water, 

v. 35, no. 2, p. 250–260.
62 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Reilly, T.E., Franke, O.L., and Bennett, G.D., 1987, The principle of superposition and its application in ground-water 

hydraulics: U.S. Geological Survey Techniques of WaterResources Investigations, book 3, chap. B6, 28 p. (Also 

available at http://pubs.usgs.gov/twri/twri3-b6/.)

Rothrock, E.P., 1955, Ground water reservoirs near Aberdeen, 

South Dakota: South Dakota Geological Survey Report of 

Investigations RI-078, 47 p., accessed March 10, 2010, at 

http://www.sdgs.usd.edu/pubs/pdf/RI-078.pdf.

Schaap, B.D., 2000, Aquifer test to determine hydraulic 

properties of the Elm aquifer near Aberdeen, South Dakota: 

U.S. Geological Survey Water-Resources Investigations 

Report 00–4264, 23 p. (Also available at http://pubs.usgs.

gov/wri/wri004264/.)

South Dakota Geological Survey, 2008, Lithologic logs database, accessed November 13, 2008, at http://www.sddenr.

net/lithdb/.

Stonestrom, D.A., and Blasch, K.W., 2003, Determining 

temperature and thermal properties for heat-based studies 

of surface-water ground-water interactions, in Constantz, J., 

and Stonestrom, D.A., eds., Heat as a tool for studying the 

movement of ground water near streams: U.S. Geological 

Survey Circular 1260, p. 74–80. (Also available at http://

pubs.usgs.gov/circ/2003/circ1260/.)

Theis, C.V., Brown, R.H., and Meyers, R.R., 1963, Estimating 

the transmissibility of aquifers from the specific capacity of wells, in Bentall, R., ed., Methods of determining 

permeability, transmissivity, and drawdown: U.S. Geological Survey Water-Supply Paper 1536–I, p. 331–340. (Also 

available at http://pubs.er.usgs.gov/publication/wsp1536I.)

Thornthwaite, C.W., and Mather, J.R., 1957, Instructions and 

tables for computing potential evapotranspiration and the 

water balance: Centerton, N.J., Laboratory of Climatology, 

Publications in Climatology, v. 10, no. 3, p. 185–311.

Tipton, M.J., 1977, Ground-water study for the city of Aberdeen: South Dakota Geological Survey Open-File Report 

16-UR, 7 p., accessed March 10, 2010, at http://www.sdgs.

usd.edu/pubs/pdf/UR-16.pdf.

U.S. Geological Survey, 2006, National Elevation Dataset—

The seamless data distribution system (SDDS), accessed 

January 15, 2010, at http://ned.usgs.gov/.

U.S. Geological Survey, 2010, National Water Information System (NWISWeb)—Groundwater levels for South 

Dakota, accessed June 1, 2011, at http://nwis.waterdata.

usgs.gov/sd/nwis/gwlevels.

U.S. Geological Survey, 2011, National Water Information 

System (NWISWeb)—USGS surface-water data for South 

Dakota, accessed March 1, 2011, at http://waterdata.usgs.

gov/sd/nwis/sw.

Westenbroek, S.M., Kelson, V.A., Dripps, W.R., Hunt, R.J., 

and Bradbury, K.R., 2010, SWB—A modified Thornthwaite-Mather soil-water-balance code for estimating 

groundwater recharge: U.S. Geological Survey Techniques 

and Methods, book 6, chap. A31, 60 p. (Also available at 

http://pubs.usgs.gov/tm/tm6-a31/.)

Won, I.J., 1980, A wideband electromagnetic exploration 

method—Some theoretical and experimental results: Geophysics, v. 45, p. 928–940.

Zohdy, A.A.R., Eaton, G.P., and Mabey, D.R., 1974, Application of surface geophysics to groundwater investigations: 

U.S. Geological Survey Techniques of Water-Resources 

Investigations, book 2, chap. D1, 116 p. (Also available at 

http://pubs.usgs.gov/twri/twri2-d1/.)
 63

Supplements 1–7
64 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Supplement 1. Electromagnetic Geophysical Surveys

This supplemental section describes electromagnetic 

(EM)	geophysical	surveys	that	were	conducted	to	determine	

the	apparent	electrical	conductivity	of	the	Earth	at	specific	

locations.	Apparent	conductivity	(inverse	of	resistivity)	can	

be used to describe the composition of the underlying materials down to a certain depth, depending on the frequency 

used.	Changes	in	conductivity	commonly	are	associated	with	

differences between lithological sequences because different 

geologic	materials	have	unique	signatures	of	conductivity.	EM	

surveys	may	be	useful	in	the	exploration	stage	for	sand	and	

gravel,	but	may	be	limited	in	the	ability	to	produce	a	detailed

characterization of a deposit (Lucius and others, 2007). Lucius 

and	others	(2007)	provide	typical	ranges	of	conductivity	for	

several	geologic	materials	(table	S1–1).	McNeil	(1980)	also	

describes	electrical	conductivity	values	of	soils	and	rocks.

Table S1–1. Approximate values and typical ranges of selected 

properties of some common geologic materials.

[Modified from Lucius and others, 2007. <, less than; >, greater than]

Material

Conductivity, 

in millisiemens per 

meter

Resistivity, 

in ohm-meters

Soil <10 to >50	 	 <20 to >100	 	

Dry sand and gravel 	 	 	 <5 >200

Saturated sand and gravel 	 	 	 >20 <50

Clay 10 to 200 5 to 100	 	

The equipment used for EM surveys was the GEM-2

sensor. The GEM-2 has a fixed coil separation of 5.45 feet (ft)

and measures apparent conductivity at various frequencies

that can range from 330 hertz (Hz) to 48 kilohertz (kHz)

(Geophex, Ltd., 2004). The equipment is designed to be highly

portable and easily operated by one person. A typical survey

involves walking with the GEM-2 over a predefined grid or

known path. Huang and Won (2003) describe several applications of the GEM-2, including mapping overburden overlying

nonconductive bedrock, defining the extent of saline ground

water, and locating buried objects.

Apparent conductivity can be used to describe the

composition of the underlying materials down to a certain 

depth, depending on the frequency used. This depth of exploration, known as “skin depth,” is inversely proportional to

frequency (Geophex, Ltd., 2004). A low frequency can travel

far through the earth and identify deep structures, whereas 

a high frequency will identify shallow structures. Geologic

materials with higher conductivities “absorb” the EM signal

and have smaller integrated depths than lower conductance

materials. Thus, areas with thick units of sand and gravel will

integrate a much deeper depth than an area that is predominantly clays. At a frequency of 14 kHz, the GEM-2 has a

penetration depth of about 50–165 ft for a conductivity range

of 10–100 millisiemens per meter (mS/m) (Won, 1980).

The penetration depth for the frequency was determined 

using the following equation (Burger and others, 2006):

δ

μ σω = 



 



 2

0

1 2/

(S1)

where

	 δ 	 is skin depth, or depth of penetration, in

meters;

μ0 = magnetic permeability for nonmagnetic 

media = 4π × 10-7 Henrys per meter;

	 σ 	 = material conductivity, in siemens per meter;

	 ω 	 = 2πf = angular frequency of the 

electromagnetic field; and

f = frequency, in hertz.

To develop a method to identify areas with high sand and

gravel content, an EM survey was conducted with a GEM-2

sensor over an area with well and test hole logs describing

the lithologic records. Data were collected along the survey

lines (fig. S1–1) using a frequency of 13,590 Hz. A correlation

between measured resistivity and the percentage of sand and

gravel from lithologic logs was calculated to identify areas

with potentially high sand and gravel composition.

Spatial referencing of data collected on land was accomplished by marking known global positioning system locations in the data file and performing an interpolation routine

to create a complete georeferenced dataset. Conductivity

readings are recorded 10 times per second and walking velocity was approximately 3–6 feet per second (ft/s), yielding a

raw data spatial resolution of about 0.3–0.6 ft per reading.

Raw data were smoothed using a 20-point running median, 

and the raw dataset was trimmed by using a 20-point centered 

average to create the final apparent conductivity values used in

analysis. Using every 20th point, the spatial resolution of the

processed conductivity data was about 10 ft.

The average conductivity was 0.053 siemens per meter 

(S/m). To determine an average depth of penetration, one standard deviation (0.027 S/m) on either side of the mean conductivity (resulting in 0.026 and 0.080 S/m) was used to calculate

a depth range of 50–88 ft. The GEM-2 records data as conductivity in millisiemens per meter. One-thousand was divided

by each conductivity value to obtain resistivity in ohm-meters

(ohm-m). The average resistivity was about 19 ohm-m.

Twenty-seven wells or test holes (table S1–2), with lithologic records about 50–88 ft deep and within about 0.05 mile

(mi) of a survey line, were selected to compare lithologic

composition with resistivity (fig. S1–2). The percentage of

sand and gravel in lithologic records was plotted against the

interpolated resistivity value for each well location (fig. S1–2).

The percentage of sand and gravel was determined by taking

the cumulative thickness of all sand and gravel deposits, and

dividing that number by the total analyzed depth of the lithologic log. The other primary constituents in the soil were clay 

and glacial till, but small amounts of topsoil and silt also were 

present.
Supplement 1. Electromagnetic Geophysical Surveys 65

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 1 2 MILES

0 1 2 KILOMETERS

EXPLANATION

! Well or test hole and map number

Electromagnetic survey line

1

!

!

!

!

! ! !

!

!

!

!

! !

!

!

!

! !

!

!

!

!

!!

!

!!

98 30' 98 27'30" 98 25'

45 35'

45 32'30"

45 37'30"

391 AVENUE

387 AVENUE

123 STREET

R. 64 W. R. 63 W.

T. 124 N.

T. 125 N.

Elm River

Elm River

Moccasin Creek

8 1 7 4 6 5

3

2

9

25

21

22

23

19

20

15

14 16

13

12

18

17

11

27

26

10

24

Figure S1–1. Location of electromagnetic survey lines and wells.
66 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

A logarithmic trend line was fitted to the dataset. The

coefficient of determination (R2) was determined to be 0.3565,

with the trend line equation of y = 17.993ln(x) - 6.4899, where

y is the percentage of sand and gravel

and x is the resistivity. The relation

indicates that resistivity greater than

35 ohm-m at a frequency of 13,590 Hz

results in a sand and gravel composition of at least 50 percent. The

percentage of sand and gravel when

the resistivity was less than 35 ohm-m

included a large range, which probably 

was related to the relative location of

clay layers and variability in skin depth.

Resistivity values were interpolated over the area. The natural

neighbor spatial analyst tool in ESRI’s

ArcMap software (http://www.esri.com/

software/arcgis/index.html) was used 

to perform the interpolation at a 30-meter (m) pixel size. The

resistivity distribution was interpolated using bins of less than

35 ohm-m, 35–60 ohm-m, 60–100 ohm-m, and greater than

100 ohm-m (fig. S1–3).

High resistivity values denoting a high percentage of

sand and gravel (fig. S1–3) in the south-central part of the

area analyzed correspond to the location of several production

wells and the glacial meltwater channel (Leap, 1986) associated with the Elm River (fig. 5). This high apparent resistivity

area seems to extend northwest toward Eyestone Pit (fig. 22).

In the area analyzed, the clay commonly was interbedded

with the sand and gravel layers at intervals ranging from 2 ft to

more than 50 ft. This layering in areas with more clay content

also results in more variability in the skin depth. The higher

resistivity values indicate fewer clay layers interbedded within

the sand and gravel and generally greater thickness of sand and

gravel. This is consistent with the examined lithologic records,

which show predominantly sand and gravel with minute traces

of thin clay beds in areas with higher resistivity values.

The two survey lines adjacent to the Elm River and

about 2 mi to the northeast of the primary EM survey area

(fig. S1–1) indicate resistivity values of less than 35 ohm-m

adjacent to resistivity values of 35–60 ohm-m. This is consistent with the other resistivity data along Elm River, where

resistivities of less than 35 ohm-m are intermingled with resistivities of 35–60 ohm-m, indicating substantial heterogeneity

in the sand and gravels along the Elm River.

Because of the uncertainty in skin depth, the GEM-2 EM

surveys were limited in characterizing areas of sand and gravel

that had substantial interbedded clays; however, areas with

apparent resistivity values greater than 35 ohm-m in the Elm

aquifer indicate a high probability for the presence of substantial sand and gravel. The location and trend of the higher

apparent resistivity values in the area surveyed is consistent

with the meltwater channel described by Leap (1986). The

apparent resistivity along the Elm River indicates that hydraulic connection of the river to the Elm aquifer may be limited

by clay layers of variable thickness with interspersed areas

that have a higher probability of hydraulic connection.

Figure S1–2. Relation between percentage of sand and gravel deposits and apparent 

electrical resistivity at a frequency of 13,590 hertz.

0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 0

10

20

30

40

50

60

70

80

90

100

Apparent electrical resistivity from electromagnetic survey, in ohm-meters (x variable)

Percentage of sand and gravel from

lithologic log (y variable) 

EXPLANATION

Well or test hole used to test

electromagnetic survey data

Logarithmic trend of data

y = 17.993ln(x) - 6.4899 

R2 = 0.3565

Table S1–2. Station names and depths of lithologic logs that 

were compared with electromagnetic resistivity surveys.

Map number 

(fig. S1–1)

Lithologic log 

station name

Total depth 

of lithologic log, in 

feet

1 124N64W01AAAD 111

2 125N63W31DCDC 64

3 125N63W31DDDC 1 60

4 125N63W31DDDC 2 110

5 125N63W32DCCC 122

6 124N63W05AAAA 50

7 124N63W04BBBB 155

8 125N63W05AAAD 182

9 124N63W06ADBB 54

10 124N63W06AADA 38

11 124N63W06AD 94

12 124N63W04BBCB 52

13 124N63W05ADDD 57

14 124N63W08ABBB 52

15 124N63W08BAAA 1 121

16 124N63W08ABBA 62

17 124N63W05DDDD 50

18 124N63W08BCBB 50

19 124N63W08BDBB 52

20 124N63W08BCC 90

21 124N63W08BDD 46

22 124N63W08DAAD 1 107

23 124N63W08DAAD 2 47

24 124N63W08DBC 57

25 124N63W08DBD 47

26 125N63W30BCAA 59

27 125N63W30CBAB 77
Supplement 1. Electromagnetic Geophysical Surveys 67

EXPLANATION

Resistivity, in ohm-meters

Less than 35

35 to less than 60

60 to less than 100

100 or greater

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 1 2 MILES

0 1 2 KILOMETERS

1 6

36 31

98 30' 98 27'30" 98 25'

45 35'

45 32'30"

45 37'30"

391 AVENUE

387 AVENUE

123 STREET

R. 64 W. R. 63 W.

T. 124 N.

T. 125 N.

Elm River

Elm River

Moccasin Creek

Figure S1–3. Apparent electrical resistivity distribution at a frequency of 13,590 hertz.
68 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Supplement 2. Direct-Current Electrical Resistivity Geophysical Surveys

Direct-current	electrical	resistivity	surveys	were	

conducted	in	the	study	area	to	determine	the	resistivity	of	the

subsurface	along	the	survey	lines	(fig.	S2–1).	The	program	

RES2DINV	was	used	to	produce	a	two-dimensional	model	of	

the	apparent	resistivity	of	the	subsurface	through	the	inversion	

of	the	data	points	using	the	“smoothness-constrained	leastsquares	method”	(Loke,	2010).	Each	profile	was	compared	

with	the	data	from	any	lithologic	logs	(South	Dakota	Geological	Survey,	2008)	located	near	the	profile	(table	S2–1)	to	

correlate	the	apparent	resistivity	of	the	profile	with	the	lithologic	units	likely	to	be	present	(technique	described	in	Kress	

and others, 2006; Lucius and others, 2007).

Resistivity	surveys	are	made	by	transmitting	current	into	

the subsurface through two current electrodes and measuring 

the	resulting	voltage	between	two	potential	electrodes.	The	

resistance	then	is	computed	by	dividing	the	measured	voltage	

by	the	transmitted	current.	Resistivity	is	the	resistance	times	

the	area	divided	by	length.	The	equipment	used	to	collect	the	

resistivity	data	was	a	multi-channel	earth	resistivity	meter	

with	56	electrode	connections.	A	programmed	series	of	

resistivity	measurements	was	made	with	a	range	in	the	combinations of current and potential electrode pairs and electrode 

spacing	in	specified	arrangements	(arrays).	The	dipole-dipole	

and	inverse	Schlumberger	arrays	used	in	the	surveys	are	

described	in	Loke	(1999)	and	Zohdy	and	others	(1974)	along	

with the characteristics of the particular array and the theory 

for	inverting	the	data	to	an	apparent	resistivity	profile.	The	

depth	of	the	area	represented	by	the	resistivity	measurement	

increases with increased electrode spacing. The dipole-dipole 

Table S2–1. Station names and depths of lithologic logs that were compared with directcurrent electrical resistivity surveys.

[--,	not	applicable]

array	has	greater	horizontal	sensitivity	than	the	inverse	

Schlumberger	array	and	provided	the	best	apparent	resistivity	

profile	when	compared	to	nearby	lithologic	logs.	The	inverse	

Schlumberger	array	has	more	vertical	sensitivity	than	the	

dipole-dipole array.

Survey	1	was	conducted	on	November	17,	2008,	

from south to north just west of the boundary between 

sections	8	and	9	in	T.	124	N.,	R.	63	W.	(fig.	S2–1).	The	

electrode	spacing	was	26.25	ft	(8	m)	for	a	survey	length	of	

1,076 ft, and the dipole-dipole array was used. Two wells, 

124N63W08DAAD	1	and	124N63W08DAAD	2,	are	150	ft	

to	the	east	of	the	profile	and	have	lithologic	logs	available	

for	comparison	at	794	ft	and	692	ft,	respectively,	along	the	

profile.	These	wells	revealed	interbedded	sand,	gravel,	and	

clay	with	layer	thicknesses	between	1	and	13	ft,	with	a	mean	

of	2	ft	and	the	thicker	layers	containing	sand	and	gravel	(South	

Dakota	Geological	Survey,	2008).	The	large	electrode	spacing	

prevented	the	detail	of	thin	layers	from	appearing	in	the	profile	

(fig.	S2–2),	but	heterogeneity	was	identifiable	throughout	the	

profile.	The	top	of	the	Elm	aquifer	was	interpreted	from	the	

profile	as	at	or	near	the	land	surface.	The	lower	boundary	of	

the	sand	and	gravel	layers	appeared	to	be	at	a	depth	of	about	

70	ft	at	the	southern	end	of	the	profile	and	at	a	depth	of	about

100	ft	at	the	northern	end.	The	apparent	resistivity	indicates	

the	presence	of	the	Middle	James	aquifer	from	400	ft	along	the	

profile	to	the	end	because	the	bottom	of	the	sandy	unit	in	the	

profile	is	at	an	altitude	of	about	1,210	ft.	A	confining	clay	layer	

between	the	Elm	and	Middle	James	aquifers	might	be	present	

even	though	one	is	not	indicated	in	the	profile.	High	resistivity	

Survey identifier

(fig. S1–1) Survey profile name(s) Lithologic log station name

Total depth of 

lithologic log, 

in feet

1 ABER1DD 124N63W08DAAD 1 107

1 ABER1DD 124N63W08DAAD 2 47

2 ABER2DD, ABER2INS 125N63W31CDAA 56

3 ABER5DD, ABER5INS 125N64W16DDDD 116

4 ABER7DD, ABER7INS -- --

5 ABER8DD -- --

6 ABER9DD, ABER9INS -- --

7 A10DDTH3 124N63W04BBCB 52

8 A10DD125_A_all 124N63W08ABBA 62

8 A10DD125_A_all 124N63W05DDDD 50

9 A10DDER1 124N63W08ABBA 62

9 A10DDER1 124N63W08BAAA 1 121

9 A10DDER1 124N63W08ABBB 52

10 A10DDER2 124N63W06ADBB 54
Supplement 2. Direct-Current Electrical Resistivity Geophysical Surveys 69

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 2 4 MILES

0 2 4 KILOMETERS

)

)

£¤281

1 6

6

6

6

6 1 1

1

6

6

1 1

6

6

31

31 31

31 36 36

36

31

31 36

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

45 30'

45 40'

98 30' 98 22'30''

1

8

6

3

4

7

9

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Columbia

Westport

2 10

5

COUNTY ROAD 16

Aberdeen

EXPLANATION

Direct-current geophysical surveys—Number

is survey identifier

Glacial landforms (Leap, 1986)

Alluvium

Delta deposits

Ground moraine

Lacustrine silt and clay

Outwash sand and gravel

Recessional moraine

Figure S2–1. Location of direct-current electrical resistivity surveys and glacial landforms.
70 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

values	at	the	surface	from	0	to	300	ft	along	the	profile	probably	indicate	unsaturated	gravel	because	survey	1	overlies	

glacial	outwash	(fig.	S2–1).

Surveys	2a	and	2b	were	conducted	on	November	18,	2008,	

one-quarter	mile	south	of	Pickus	Pit	(fig.	22)	in	section	31	of	

T.	125	N.,	R.	63	W.	(fig.	S2–1).	The	surveys	were	measured	

from south to north with an electrode spacing of 16.40 ft 

(5	m)	using	the	dipole-dipole	(survey	2a;	fig.	S2–3A) and 

inverse	Schlumberger	(survey	2b;	fig.	S2–3B)	arrays.	Well	

125N63W31CDAA	lies	on	the	survey	line	515	ft	from	the	

southern	end,	and	the	total	survey	length	is	672	ft.	The	lithologic log at this well indicates that the top and bottom of the 

Elm	aquifer	are	at	depths	of	13	and	46	ft,	respectively	(South	

Dakota	Geological	Survey,	2008).	The	two	data	collection	

arrays	produced	slightly	different	profiles	during	inversion	in	

RES2DINV.	The	inverse	Schlumberger	profile	(fig.	S2–3B) 

produced	a	consistent	apparent	resistivity	value	of	about	

40	ohm-m	for	the	top	and	bottom	of	the	Elm	aquifer	at	depths	

that approximately matched the lithologic log. The dipoledipole	profile	must	have	an	apparent	resistivity	of	24	ohm-m	at	

the	bottom	of	the	aquifer	and	40	ohm-m	at	the	top	if	the	profile

is	made	to	match	the	aquifer	thickness	as	interpreted	from	the	

lithologic	log.	Surveys	2a	and	2b	were	conducted	in	alluvium	

(fig.	S2–1)	where	little	overlying	material	exists,	which	agrees

with	the	lithologic	log	and	profiles.

Surveys	3a	and	3b	were	conducted	on	November	19,	2008,	

between	sections	21	and	22	of	T.	125	N.,	R.	64	W.	(fig.	S2–1).	

The	electrode	spacing	was	16.40	ft	(5	m),	and	the	survey	was	

done	from	south	to	north	for	902	ft	with	the	dipole-dipole	

(survey	3a;	fig.	S2–4A)	and	inverse	Schlumberger	(survey	

3b;	fig.	S2–4B)	arrays.	The	northern	end	of	the	survey	was	

about	0.3	mi	south	of	well	125N64W16DDDD.	The	profile	

indicates	that	the	top	of	the	Elm	aquifer	is	at	or	near	the	

land	surface	because	the	highest	resistivities	(18–27	ohm-m)	

exist there. The underlying shale was estimated to be at a 

depth	of	about	80	ft,	with	an	apparent	resistivity	of	less	than	

8	plus	or	minus	2	ohm-m.	At	well	125N64W16DDDD,	the	

top	of	the	shale	is	82	ft	below	the	land	surface	according	to	

the	lithologic	log	(South	Dakota	Geological	Survey,	2008).	

The lithologic log indicated upper and lower sand units 

with	thicknesses	of	18	and	15	ft,	respectively	(South	Dakota	

Geological	Survey,	2008).	The	sand	units	were	separated	by	

37	ft	of	clay	(South	Dakota	Geological	Survey,	2008).	The	

sand	units	appear	to	have	merged	in	the	area	of	the	survey,	

but	the	profile	is	not	sufficiently	detailed	to	give	certainty.	

The	dipole-dipole	profile	(fig.	S2–4A) indicates horizontal 

discontinuity	within	the	Elm	aquifer,	particularly	between	

about	220	and	300	ft	along	the	survey	line.	The	inverse	

Schlumberger	profile	(fig.	S2–4B) places the discontinuity 

between	160	and	280	ft	along	the	survey	line.	The	degree	of	

connection between the sandy units to the north and south 

of the discontinuity cannot be readily determined from the 

profile	alone.	The	resistivity	of	the	part	of	the	profile	interpreted	as	the	Elm	aquifer	seems	to	be	greater	than	about	

18	ohm-m.	The	relatively	low	value	interpreted	for	the	boundary	of	the	Elm	aquifer	is	caused	by	high	clay	content,	which	

corresponds well with the landform that was mapped by Leap 

(1986)	as	a	recessional	moraine	(fig.	S2–1).

Surveys	4a	and	4b	were	conducted	on	November	19,	2008,	

about	30	ft	west	of	the	boundary	between	section	20	and	21	

of	T.	125	N.,	R.	63	W.	(fig.	S2–1).	The	surveys	were	done	

from	south	to	north	with	an	electrode	spacing	of	13.12	ft	(4	

m)	for	722	ft	using	the	dipole-dipole	(survey	4a;	fig.	S2–5A) 

and	inverse	Schlumberger	(survey	4b;	fig.	S2–5B) arrays. The 

resistivity	profiles	indicate	that	the	top	of	the	Elm	aquifer	is

at	a	depth	of	about	25	ft	and	the	bottom	of	the	aquifer	is	at	a

depth	of	about	110	to	130	ft.	The	apparent	resistivity	of	the	top	

of	the	aquifer	is	about	16.5	to	21	ohm-m,	with	differences	in	

the	dipole-dipole	and	inverse	Schlumberger	profiles	increasing the uncertainty of the model interpretation. The maximum 

apparent	resistivity	within	the	profiles	was	about	25	ohm-m,	so	

the	apparent	uniformity	of	the	aquifer	in	the	inverse	Schlumberger	profile	(fig.	S2–5B) may be from the smoothing of 

interbedded	sand	and	clay.	The	heterogeneous	layer	above	the	

Elm	aquifer	is	consistent	with	till	because	the	survey	location

is	within	the	ground	moraine	(fig.	S2–1).

0

40.0

80.0

120.0

160.0

200.0

12.0 18.0 24.0 30.0 60.0 100 200 400

Depth

0 160.0 320.0 480.0 640.0 800.0 960.0

EXPLANATION

Iteration 7 absolute error = 2.1 percent Unit electrode spacing 26.25 feet

Inverse model resistivity section

[Resistivity, in ohm-meters]

Distance, in feet

SOUTH NORTH

Figure S2–2. Resistivity profile for survey 1.
Supplement 2. Direct-Current Electrical Resistivity Geophysical Surveys 71

Survey	5	was	conducted	on	November	20,	2008,	in	the	

northwestern	quarter	of	section	17	of	T.	124	N.,	R.	63	W.	

(fig.	S2–1).	The	survey	was	conducted	from	south	to	north	as	

a	roll-along	survey	totaling	1,082	ft	with	an	electrode-spacing

of	19.68	ft	(6	m)	and	the	dipole-dipole	array.	In	a	roll-along	

survey,	the	first	28	of	the	56	electrodes	are	picked	up	and	

attached	to	the	end	the	survey	line,	and	the	collection	of	the	

data	continues	to	create	a	continuous	profile	of	the	desired	

length.	The	Elm	aquifer	top	seems	to	be	at	the	land	surface	

near	the	middle	of	the	profile	(fig.	S2–6)	and	at	depths	of	

about	20	to	30	ft	near	the	edges.	The	Elm	aquifer	probably	

includes	clay	in	the	area;	however,	the	resistivity	of	the	60-	to	

80-ft	thick	aquifer	layer	is	greater	than	24	ohm-m,	indicating	

more	sand	and	gravel	than	in	other	surveyed	areas.	Some	sand	

and	gravel	likely	are	present	below	a	depth	of	about	120	ft	

because	the	apparent	resistivity	is	15	to	21	ohm-m.	Survey	5	is

within	the	delta	deposits	mapped	by	Leap	(1986)	(fig.	S2–1).

Surveys	6a	and	6b	were	conducted	on	November	20,	2008,	

in	the	northwestern	quarter	of	section	17,	T.	124	N.,	R.	63	W.	

and	overlapped	the	northern	end	of	survey	5	(fig.	S2–1).	The	

surveys	were	conducted	from	south	to	north	with	an	electrode	

spacing of 19.68 ft (6 m) for 1,082 ft using the dipole-dipole

(survey 6a; fig. S2–7A) and inverse Schlumberger (survey

6b; fig. S2–7B) arrays. The top of the Elm aquifer seems to

be at depths of less than 20 ft and at the land surface in some 

places. The thickness of the Elm aquifer is about 45 to 90

ft with the variability caused, in part, by limited contrast in

apparent resistivity. The apparent resistivity from about 90 to

120 ft deep ranges from 8.5 to 21 ohm-m. The slow transition

from the Elm aquifer above a depth of 90 ft to the clay below

a depth of about 130 ft might indicate that a small layer of the

Middle James aquifer is present in the area. The resolution

of the data lowers with depth, so the profile cannot provide

definitive evidence of the presence of a thin sand unit. Similar

to survey 5, surveys 6a and 6b are in the delta deposits

(fig. S2–1).

Survey 7 was conducted on June 1, 2010, about 25 ft

east of the boundary between sections 4 and 5 of T. 124 N.,

R. 63 W. (fig. S2–1). The survey was conducted from south to

north with an electrode spacing of 9.84 ft (3 m), total length of

541.2 ft, and the dipole-dipole array. Well 124N63W04BBCB

lies about 220 ft from the southern end of the survey. The

0

25.0

50.0

75.0

100.0

6.5 9.00 11.0 15.0 21.0 27.0 40.0 80.0

Depth

0 160.0 320.0 480.0 640.0

EXPLANATION

Iteration 8 absolute error = 1.07 percent Unit electrode spacing 16.40 feet

Inverse model resistivity section

[Resistivity, in ohm-meters]

0

25.0

50.0

75.0

100.0

6.5 9.00 11.0 15.0 21.0 27.0 40.0 80.0

Depth

0 160.0 320.0 480.0 640.0

EXPLANATION

Iteration 11 absolute error = 0.49 percent Unit electrode spacing 16.40 feet

Inverse model resistivity section

[Resistivity, in ohm-meters]

Distance, in feet

Distance, in feet

A

B

SOUTH NORTH

SOUTH NORTH

Figure S2–3. Resistivity profiles for survey 2. A, Dipole-dipole profile, and B, inverse Schlumberger profile.
72 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

lithologic	log	indicated	interbedded	sand	and	gravel	with	clay	

from	10	to	40	ft	deep	and	clay	with	gravel	from	40	to	52	ft	

deep	(South	Dakota	Geological	Survey,	2008).	The	well	was	

drilled	only	to	a	depth	of	52	ft	(South	Dakota	Geological	

Survey,	2008),	whereas	the	profile	(fig.	S2–8)	shows	120	ft;	

therefore, the comparison between the lithologic log and the 

resistivity	profile	is	limited.	The	profile	has	an	average	apparent	resistivity	of	13.5–15	ohm-m	from	0–30	ft	deep	and	of	

21–24	ohm-m	from	30–75	ft	deep.	This	profile	demonstrates	

the	limitation	of	apparent	resistivity	data	in	characterizing	the	

heterogeneous layering that commonly exists in glacial deposits.	The	location	of	survey	7	was	in	ground	moraine	(fig.	S2–1).

Surveys	A10DD125	and	A10DD125A	were	conducted	on	

June	3,	2010,	in	section	8	of	T.	124	N,	R.	63	W.	The	surveys	

were carried out from east to west, with an electrode spacing of 

6.56	ft	(2	m)	with	the	dipole-dipole	array.	These	were	roll-along	

surveys	and	the	first	movement	of	the	electrodes	was	incorrectly	

conducted	in	survey	A10DD125.	The	survey	was	begun	again	at	

this	point	(A10DD125A)	and	the	datasets	were	combined.	The	

usable	data	from	the	two	surveys	were	combined	to	form	one	

profile, survey 8 (fig. S2–9), with a total length of 1,082 ft, by

using the concatenation function in RES2DINV (Loke, 2010)

because 28 of the electrodes from each survey were identical.

Well 124N63W08ABBA is 752 ft to the east of the western end

of the concatenated profile. Well 124N63W05DDDD is located

245 ft north-northeast of the eastern end of the profile. The

lithologic data from both wells indicate that the top of the Elm

aquifer is about 10 ft below the land surface, and the bottom of 

the aquifer is at a depth of 44 to 56 ft (South Dakota Geological

Survey, 2008). To match these data exactly, the apparent resistivity values of the top and bottom of the Elm aquifer would be

about 15 and 25 ohm-m, respectively. Based on the profile, the

top of the Elm aquifer seems to be at a depth of about 20 ft and

the thickness varies from potentially as little as 20 ft to about

40 ft. The possible thinning of the aquifer near the center of the 

profile indicates the presence of more clay near the center than

closer to the edges of the profile. The apparent resistivity range

of 21 to 24 ohm-m where the aquifer might be thinner indicates 

that sand is still present. The entire length of survey 8 was

located in delta deposits (fig. S2–1).

0

25.0

50.0

75.0

100.0

125.0

150.0

175.0

5.00 8.00 10.0 12.0 15.0 18.0 24.0

Depth

0 320.0 640.0

EXPLANATION

Iteration 5 absolute error = 1.56 percent Unit electrode spacing 16.40 feet

Inverse model resistivity section

[Resistivity, in ohm-meters]

0

25.0

50.0

75.0

100.0

125.0

150.0

175.0

5.00 8.00 10.0 12.0 15.0 18.0 24.0

Depth

0 320.0 640.0

EXPLANATION

Iteration 4 absolute error = 0.94 percent Unit electrode spacing 16.40 feet

Inverse model resistivity section

[Resistivity, in ohm-meters]

A

B

Distance, in feet

Distance, in feet

SOUTH NORTH

SOUTH NORTH

Figure S2–4. Resistivity profiles for survey 3. A, Dipole-dipole profile, and B, inverse Schlumberger profile.
Supplement 2. Direct-Current Electrical Resistivity Geophysical Surveys 73

0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

5.00 8.00 10.0 12.0 15.0 18.0 24.0

Depth

0 320.0 640.0

EXPLANATION

Iteration 7 absolute error = 0.92 percent Unit electrode spacing 13.12 feet

Inverse model resistivity section

[Resistivity, in ohm-meters]

A

0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

5.00 8.00 10.0 12.0 15.0 18.0 24.0

Depth

0 320.0 640.0

EXPLANATION

Iteration 8 absolute error = 0.28 percent Unit electrode spacing 13.12 feet

Inverse model resistivity section

[Resistivity, in ohm-meters]

B

Distance, in feet

Distance, in feet

SOUTH NORTH

SOUTH NORTH

Figure S2–5. Resistivity profile for survey 4. A, Dipole-dipole profile, and B, inverse Schlumberger profile.

0

30.0

60.0

90.0

120.0

150.0

180.0

210.0

8.00 10.00 12.0 15.0 18.0 24.0 30.0 60.0

Depth

0 320.0 640.0 960.0

EXPLANATION

Iteration 5 absolute error = 0.78 percent Unit electrode spacing 19.68 feet

Inverse model resistivity section

[Resistivity, in ohm-meters]

Distance, in feet

SOUTH NORTH

Figure S2–6. Resistivity profile for survey 5.
74 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

0

30.0

60.0

90.0

120.0

150.0

180.0

210.0

6.50 9.00 11.0 13.5 16.5 21.0 27.0 40.0

Depth

0 320.0 640.0 960.0

EXPLANATION

Iteration 5 absolute error = 1.08 percent Unit electrode spacing 19.68 feet

Inverse model resistivity section

[Resistivity, in ohm-meters]

A

0

30.0

60.0

90.0

120.0

150.0

180.0

210.0

6.50 9.00 11.0 13.5 16.5 21.0 27.0 40.0

Depth

0 320.0 640.0 960.0

EXPLANATION

Iteration 7 absolute error = 0.37 percent Unit electrode spacing 19.68 feet

Inverse model resistivity section

[Resistivity, in ohm-meters]

B

Distance, in feet

Distance, in feet

SOUTH NORTH

SOUTH NORTH

Figure S2–7. Resistivity profiles for survey 6. A, Dipole-dipole profile, and B, inverse Schlumberger profile.

0

15.0

30.0

45.0

60.0

75.0

90.0

105.0

120.0

5.00 8.00 10.0 12.0 15.0 18.0 24.0 30.0

Depth

0 320.0

EXPLANATION

Iteration 5 absolute error = 0.82 percent Unit electrode spacing 9.84 feet

Inverse model resistivity section

[Resistivity, in ohm-meters]

Distance, in feet

SOUTH NORTH

Figure S2–8. Resistivity profile for survey 7.
Supplement 2. Direct-Current Electrical Resistivity Geophysical Surveys 75

Survey	9	was	completed	on	June	2,	2010,	on	the	southern	side	of	the	Elm	River	in	section	5	of	T.	124	N.,	R.	63	W.	

(fig.	S2–1).	The	survey	was	conducted	from	northeast	to	

southwest.	The	survey	used	an	electrode	spacing	of	9.84	ft	

(3	m)	over	a	length	of	541	ft	and	the	dipole-dipole	array.	

Well	124N63W08ABBA	is	415	ft	to	the	southeast	of	the	

eastern	end	of	the	profile	and	across	the	Elm	River.	Well	

124N63W08BAAA	1	is	226	ft	to	the	southeast	of	the	western	

end	of	the	profile	(fig.	S2–10).	Well	124N63W08ABBB	is	

345	ft	to	the	west-southwest	of	the	western	end	of	the	profile,	

but	not	quite	on	the	same	line	as	the	survey.	The	primary	difference between the three lithologic logs was that the top of the 

aquifer	was	closest	to	the	surface	at	well	124N63W08ABBA	at	

a	depth	of	10	ft	and	the	aquifer	was	46	ft	thick	(South	Dakota	

Geological	Survey,	2008).	The	other	two	lithologic	logs	indicated	that	the	uppermost	sand	intervals	were	at	depths	of	23	

ft	and	29	ft,	with	the	bottom	of	the	aquifer	at	a	depth	of	45	ft	

(South	Dakota	Geological	Survey,	2008).	All	three	lithologic	

logs	indicated	interbedded	clay	with	the	sand	(South	Dakota	

Geological	Survey,	2008).	The	top	of	the	Elm	aquifer	was	

interpreted	to	be	about	15	to	20	ft	deep	in	the	profile,	with	an	

apparent	resistivity	of	24	to	27	ohm-m	at	the	top	of	the	aquifer.	

The	minimum	aquifer	thickness	in	the	profile	was	about	20	ft.	

Survey	9	is	in	the	delta	deposits	(fig.	S2–1).

Survey	10	was	completed	on	June	2,	2010,	on	the	southern	side	of	the	Elm	River	in	the	northeast	quarter	of	section	6

of	T.	124	N.,	R.	63	W.	(fig.	S2–1).	The	survey	was	conducted	

from the northeast to the southwest, with an electrode spacing 

of	6.56	ft	(2	m)	and	with	only	42	electrodes.	Survey	10	was	

269	ft	long	(fig.	S2–11)	and	was	truncated	at	the	Eyestone	

Pit	(fig.	22).	Well	124N63W06ADBB	was	58	ft	to	the	northnorthwest	of	the	southwestern	end	of	the	survey.	The	profile	

indicated that the top of the Elm aquifer was at a depth of 20

to 35 ft. According to the lithologic log, the top of the Elm

aquifer was at 19 ft and the aquifer thickness was 30 ft (South

Dakota Geological Survey, 2008). The lithologic log indicated

sand in the upper 15 ft and gravel in the lower 15 ft of the Elm

aquifer (South Dakota Geological Survey, 2008). The apparent resistivity at the top of the Elm aquifer was about 24 to

30 ohm-m for a depth of about 20 ft. The profile indicated that

the bottom of the Elm aquifer was lower than indicated by the

lithologic log. Based on the resistivity profile, the bottom of

the Elm aquifer seems to be at about 55 ft to 60 ft below the

land surface. Survey 10 was in glacial outwash (fig. S2–1),

which is reasonable for the thickness of the sand and gravel

layers and the presence of the Eyestone Pit.

From the comparison to lithologic logs, the direct-current 

resistivity profiles gave approximate depths and thicknesses

for the Elm aquifer, but did not provide sufficient detail

to identify clay interbeds or an exact depth for the top and 

bottom of the aquifer. The Elm aquifer seems to have resistivity values greater than 30 ohm-m when sand and gravel are

the predominant sediments. When sand is interbedded with

layers of clay, the resistivity values in the Elm aquifer are

lowered to values greater than 18 ohm-m and possibly as low

as 15 ohm-m. The resistivity of the interbeds was collected

as an average, partly because the electrode spacing used was

6.56 ft (2 m) or larger, whereas the interbeds commonly were

1 to 6 ft thick. The Middle James aquifer might have been

present at some of the survey locations; however, the thickness

of the unit was difficult to determine because the resolution of

the profiles decreased with depth. The resistivity values within

any profile are quite variable and the different profiles demonstrate the spatial variability of the glacial aquifer thickness.

0

20.0

40.0

60.0

80.0

120.0

100.0

140.0

160.0

5.00 9.00 11.0 13.5 16.5 21.0 27.0 40.0

Depth

0 320.0 640.0 960.0

EXPLANATION

Iteration 4 absolute error = 0.99 percent Unit electrode spacing 6.56 feet

Inverse model resistivity section

[Resistivity, in ohm-meters]

Distance, in feet

EAST WEST

Figure S2–9. Resistivity profile for survey 8.
76 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

0

15.0

30.0

45.0

60.0

75.0

90.0

105.0

120.0

5.00 8.00 10.0 12.0 15.0 18.0 24.0 30.0

Depth

0 320.0

EXPLANATION

Iteration 4 absolute error = 1.18 percent Unit electrode spacing 9.84 feet

Inverse model resistivity section

[Resistivity, in ohm-meters]

Distance, in feet

NORTHEAST SOUTHWEST

Figure S2–10. Resistivity profile for survey 9.

0

10.0

20.0

30.0

40.0

50.0

60.0

5.00 8.00 10.0 12.0 15.0 18.0 24.0 30.0

Depth

0 160.0

EXPLANATION

Iteration 4 absolute error = 0.48 percent Unit electrode spacing 6.56 feet

Inverse model resistivity section

[Resistivity, in ohm-meters]

Distance, in feet

NORTHEAST SOUTHWEST

Figure S2–11. Resistivity profile for survey 10.
Supplement 3. Aquifer Test of Elm Aquifer at Eyestone Pit 77

Supplement 3. Aquifer Test of Elm Aquifer at Eyestone Pit

have a head equal to the starting hydraulic head of the aquifer

and a bottom altitude 7 ft below the head on the basis of the 

average depth of the Elm River in the aquifer test analysis

area.

The cells representing the Eyestone and Jacob Pits were

assigned a high hydraulic conductivity of 8.78×106 ft/d and a

storage coefficient of 0.99 to approximate the hydraulic properties of the pit area. The horizontal hydraulic conductivity of the

Elm aquifer, the confined storage coefficient of the Elm aquifer,

and the riverbed conductance were the independent variable

parameters estimated by the numerical modeling process.

The model simulated pumping from the well at Eyestone

Pit in transient state with 14 stress periods each about 0.5 day

in length (table S3–1). The pumping well discharged at

1.547 ft3/s for the first 3.625 days (stress periods 1–7), and

then the pumping rate was increased to 3.095 ft3/s for the

next 3 days of the aquifer test (stress periods 8–13). Stress

period 14 in the 7-day simulation represented 0.375 days after

pumping was ended. The purpose of this stress period was 

to allow calibration to some measurements that were made 

shortly after the pumping ceased.

An	aquifer	test	of	the	Elm	aquifer	was	conducted	from	

September	14	to	21,	2009,	by	pumping	a	well	at	Eyestone	

Pit	for	6.625	days	and	measuring	drawdown	in	observation	

wells	PZ2,	PZ3,	and	PZ5,	and	the	water	level	of	Eyestone	

Pit	at	observation	well	Pit1	(fig.	S3–1).	The	pumping	well	

discharged	water	at	a	rate	of	1.547	cubic	feet	per	second	

(ft3/s)	for	the	first	3.625	days,	and	then	the	pumping	rate	was	

increased	to	3.095	ft3/s	for	the	remainder	of	the	aquifer	test.	

Discharged	water	was	removed	from	the	site	and	not	allowed	

to spill onto the land surface.

A	numerical	model	was	constructed	to	simulate	the	

aquifer test and calculate hydraulic properties by using 

MODFLOW-2005	(Harbaugh,	2005)	and	the	principle	of	

superposition.The principle of superposition states that 

solutions	to	individual	components	of	a	linear	problem	can	

be	added	to	solve	composite	problems	(Reilly	and	others,	

1987);	therefore,	the	aquifer	test	could	be	simulated	in	terms	

of	hydraulic	head	change	rather	than	the	actual	values.	Initial	

conditions were simulated as zero change, representing no 

drawdown and a uniform starting hydraulic head. The static 

water	level	in	the	three	observation	wells	ranged	from	7	to	

9	ft	above	the	top	of	the	aquifer.	The	aquifer	was	assumed	to	

be	confined	throughout	the	aquifer	test	analysis	area;	therefore,	the	assumption	of	linearity	was	valid.

The	model	was	composed	of	one	layer,	the	Elm	aquifer,	

which was assumed to be underlain by impermeable sediments 

in the aquifer test analysis area. The aquifer test analysis area 

(fig.	S3–1,	fig.	22)	consisted	of	150	rows	and	150	columns,	all	

of	which	were	33.33	ft	(10.16	m)	wide.	The	grid	was	extended	

to	a	total	of	395	rows	oriented	east	to	west	and	356	columns	

oriented north to south, with cell sizes increasing at a ratio of 

1.3	or	less	toward	the	boundary	of	the	model	area	from	the	

central aquifer test analysis area. This extended the boundaries	of	the	model	area	134	miles	from	the	5,000	ft	by	5,000	ft	

aquifer test analysis area to minimize the effects of the boundaries on analysis of hydraulic properties. The cells bounding 

the	grid	were	simulated	as	constant	head	cells.	The	inflow	

from the constant head cells in the simulation was small, less 

than	5.0×10-6 ft3

/s.

A	uniform	thickness	of	30	ft	for	the	Elm	aquifer	was	

assumed	on	the	basis	of	the	average	thickness	of	the	aquifer	

determined from lithologic logs in the aquifer test analysis 

area. The starting hydraulic head was assumed to be 6 ft 

above	the	top	of	the	aquifer	on	the	basis	of	the	average	of	

hydraulic	head	values	throughout	the	aquifer	test	analysis	

area.	The	hydraulically	connected	Elm	River	was	assumed	to	

Table S3–1. Pumping rate and time for each stress 

period.

[ft3/s, cubic feet per second]

Stress period Stress period length 

(days)

Pumping rate 

(ft3

/s)

1 0.500 1.547

2 0.500 1.547

3 0.500 1.547

4 0.500 1.547

5 0.500 1.547

6 0.500 1.547

7 0.625 1.547

8 0.375 3.095

9 0.500 3.095

10 0.500 3.095

11 0.500 3.095

12 0.500 3.095

13 0.625 3.095

14 0.375 0.00
78 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Base from U.S. Geological Survey digital data, 1995, 1:100,000 

Universal Transverse Mercator Projection, Zone 14 North

0 0.1 0.2 MILE

0 0.1 0.2 KILOMETER

EXPLANATION

Observation wells with site identifier

") Pumping well

!

PZ2

45°35'20"

45°35'

98°27'40" 96°27'

R. 63 W.

T. 125 N.

") T. 124 N.

!

!

!

!

PZ2

PZ3

PZ5

Pit1

Jacob Pit

Eyestone Pit

Elm River

Figure S3–1. Location of Eyestone Pit, pumping well, and observation wells for Eyestone Pit aquifer test.
Supplement 3. Aquifer Test of Elm Aquifer at Eyestone Pit 79

The hydraulic head at the observation wells was monitored before and after the tests to estimate trends in hydraulic 

heads that existed during the aquifer test (fig. S3–2). The same

trend in hydraulic head was evident at all four observation

wells. The hydraulic head estimated from the trend line rose 

about 0.1 foot during the aquifer test. The observed drawdown

was calculated by subtracting the measured hydraulic head 

from the trend line values (table S3–2).

The simulated drawdown for the four observation wells

was then optimized to determine the best fit to the observed

drawdown by using the parameter estimation software Parameter ESTimation code (PEST) (Doherty, 2005). PEST uses

nonlinear estimation techniques as described by Levenberg

(1944), Marquardt (1963), and Doherty (2005) to iteratively

estimate parameters. New parameter values were calculated

until the residuals, or differences between the observed and

simulated drawdown, were minimized.

The parameter estimation process resulted in small residuals between the observed and simulated drawdown values

(table S3–2). Linear regression between the 36 observed and

simulated drawdown values had a coefficient of determination (R2 value) of 0.98 with an average arithmetic difference

of -0.02 ft and an average absolute difference of 0.05 ft. The

calculated hydraulic properties were 418 ft/d for hydraulic

conductivity, 2.4×10-5 for confined storage coefficient, and

46 ft2/d for riverbed conductance. The rate of induced flow

from the Elm River during the last pumping stress period was

0.46 ft3/s.

Table S3–2. Observed and simulated drawdown for the 

Eyestone Pit aquifer test.

Elapsed time since 

start of pumping 

(days)

Drawdown (feet)

Observed Simulated

Observation well Pit1

0.50 0.14 0.14

1.00 0.28 0.26

1.50 0.39 0.37

2.00 0.51 0.47

2.50 0.59 0.56

3.00 0.71 0.64

3.50 0.79 0.72

4.00 0.87 0.89

4.50 1.07 1.08

5.00 1.27 1.26

5.50 1.42 1.42

6.00 1.61 1.56

6.50 1.66 1.70

Observation well PZ3

0.50 0.16 0.07

1.00 0.23 0.13

1.50 0.29 0.18

2.00 0.34 0.23

2.50 0.37 0.28

3.00 0.42 0.33

3.50 0.45 0.37

4.00 0.52 0.46

4.50 0.56 0.56

5.00 0.64 0.65

5.50 0.71 0.74

6.00 0.81 0.82

6.50 0.88 0.89

Observation well PZ5

0.66 0.10 0.15

0.85 0.15 0.19

1.16 0.21 0.25

1.67 0.29 0.34

1.95 0.34 0.39

2.69 0.47 0.51

6.73 1.41 1.46

Observation well PZ2

1.69 0.15 0.16

2.64 0.37 0.24

6.68 0.67 0.79

Hydraulic head, in feet below land surface

3

5

7

9

11

13

15

17

08/01/2009 08/21/2009 09/10/2009 09/30/2009 10/20/2009 11/09/2009 11/29/2009

Date (month/day/year)

NOTE:

PIT1

PZ5

PZ2

PZ3

Points are individual water-level measurements at the specified site.

Colored lines are continuous water-level measurements from transducers at the specified site.

Black lines are the same trend overlying the data for each site.

Trend line = Starting hydraulic head * 0.003 * (elapsed days)^1.35

Figure S3–2. Comparing hydraulic head for observation wells Pit1, 

PZ2, PZ3,and PZ5, and trends in hydraulic head.
80 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Supplement 4. Estimates of Hydraulic Conductivity from Specific Capacity Tests

Data	from	seven	production	wells	(center	of	fig.	22;	

table	S4–1)	were	analyzed	to	determine	transmissivity	values	

for	the	Elm	aquifer.	Specific	capacity	tests,	where	the	well	was

pumped at a constant rate and the drawdown was measured 

after	12	hours,	were	conducted	on	the	seven	wells	when	they	

were	constructed	in	2005.	The	static	water	levels	indicated	

that	this	part	of	the	aquifer	was	unconfined.	The	Theis	and	

others	(1963)	method	used	in	this	analysis	probably	is	the	

most	common	way	to	analytically	estimate	transmissivity	

from	specific	capacity	(Mace,	2001).	Well	construction	data	

included	saturated	thickness,	well	radius,	pumping	rate,	drawdown,	and	pumping	period.	The	specific	yield,	which	is	the	

storage	term	for	unconfined	aquifers,	was	assumed	to	be	0.10	

because	typical	values	range	from	0.01–0.30	for	unconfined	

aquifers	(Freeze	and	Cherry,	1979).

Transmissivity	for	the	unconfined	glacial	till	aquifer	

was	calculated	using	a	form	of	the	Theis	and	others	(1963)	

nonequilibrium equation:

The assumptions behind this equation are that the well 

is fully penetrating, the porous media is homogeneous and 

isotropic,	the	well	loss	is	negligible,	and	the	effective	radius	is	

equal	to	the	radius	of	the	production	well	(Mace,	2001).	The	

equation	was	solved	iteratively	by	rearranging	equation	S4A	

to	solve	for	transmissivity	(T) in the numerator (equation S4B) 

according	to	Mace	(2001):

(S4B)

S T

Tt

r S

c

p

w

= 



 



 



 





4

2 25

2

π

ln . (S4A)

where

Sc is specific capacity, in gallons per day per foot;

T 	 = transmissivity, in gallons per day per foot;

rw = radius of the well, in feet;

S 	 = storativity, unitless; and

t

p = pumping time, in days.

T S Tt

r S

c p

w

= 



 



 4

2 25

2 π

ln .

Values for specific capacity (Sc), pumping time (t

p

), and 

well radius (rw) were available from the well completion

report, and an initial guess for the T in the numerator was used 

to calculate the T on the left side of the equation. The calculated T was then substituted back into the equation, and this

process was repeated using an iterative function until the T on 

the left side was almost the same as the T in the right side of 

the equation.

Based on this method, the average transmissivity for the

Elm aquifer was determined to be 5,300 ft2/d, with a range

of 2,550 to 8,180 ft2/d. Horizontal hydraulic conductivity for

the Elm aquifer was calculated by dividing transmissivity by

the saturated thickness of the aquifer. The average hydraulic

conductivity was determined to be 143 ft/d, with a range of

97 to 205 ft/d (table S4–1).

Table S4–1. Specific capacity data and estimated hydraulic conductivity for seven production wells in Aberdeen area.

[ft, feet; gal/min/ft, gallons per minute per foot; ft/d, feet per day]

Well identifier 

(fig. 22)

Saturated aquifer 

thickness 

(ft)

Well radius 

(ft)

Pumping rate

(gal/min)

Drawdown 

(ft)

Specific

capacity

(gal/min/ft)

Estimated horizontal 

hydraulic conductivity 

(ft/d)

J–1 35.1 0.5 390 17.7 22.0 117

B–1 26.3 0.5 150 10.5 14.3 97

B–2 35.1 0.5 400 13.4 29.9 162

B–3 40.0 0.5 400 9.6 41.7 205

B–4 29.5 0.5 200 11.4 17.5 108

B–5 50 0.5 400 12.8 31.3 120

B–6 38.8 0.5 400 10.5 38.1 191
Supplement 5. Estimating Vertical Hydraulic Conductivity of Sediments Separating the Elm River and Elm Aquifer using Temperature 81

Supplement 5. Estimating Vertical Hydraulic Conductivity of Sediments 

Separating the Elm River and Elm Aquifer using Temperature

was used above the screened well point at four sites in 2008,

and pipe with small (1/8-inch) holes was installed at seven

sites in 2009. Two temperature loggers were placed within

the casing, one near the bottom point and the other approximately 3–6 ft above the bottom logger. The casing was driven

into the streambed at a slight angle towards the bank down

to a depth so the bottom point was about 4–6 ft below the

streambed surface at the edge of the stream. A third logger

was placed directly in the stream near the casing to measure 

stream temperature. Water temperatures were recorded every

5 minutes.

Eleven driven piezometers were installed adjacent to

the Elm River to determine the hydraulic gradient between

the Elm River and Elm aquifer (table S5–1; fig. 23), with 6

of the 11 piezometers in the direct vicinity of temperature

monitoring sites. The hydraulic gradient, in combination 

with the Darcy velocity, determined from analysis of the

temperature data (see “Temperature Modeling” section) was

used to calculate vertical hydraulic conductivity at six of

the temperature monitoring sites (table S5–2). Water levels

were measured periodically at the piezometer sites during 

May–September 2009. The stage of the Elm River near each

To	examine	the	interaction	of	the	Elm	River	and	the	

Elm	aquifer,	a	method	that	tracks	energy	exchange	was	used

primarily by using temperature measurements to estimate 

the	hydraulic	transport	properties	of	the	stream/groundwater	system	at	a	specific	location.	This	section	describes	the	

temperature	monitoring	(figs.	S5–1	and	S5–2;	tables	S5–1	

and	S5–2),	modeling	method	used	in	estimating	vertical	

hydraulic	conductivity	from	temperature	gradients	(table	

S5–3),	and	the	temperature	modeling	results	(figs.	S5–3	

through	S5–14).

Temperature Monitoring

Temperature	monitoring	was	conducted	in	2008–09	

at	11	sites	along	the	Elm	River	(fig.	23)	to	estimate	the	

Darcy	velocities	and	the	flow	direction	as	described	in	the	

“Temperature	Modeling”	section.	The	equipment	used	to	

monitor the temperature gradient included stainless steel 

casing	and	programmed	temperature	loggers	(fig.	S5–1).	A	

3-ft	screened	steel	well	point	was	connected	to	steel	casing	

that	extended	above	the	Elm	River	water	surface.	Solid	pipe	

,

Figure S5–1. Stainless steel casing and temperature logger.
82 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

piezometer was estimated for each day that the water levels

in the piezometers were measured. The Elm River stage was

estimated using the stage record from streamgage 06471500

near Westport (fig. 1) and the surveyed altitude difference

between the streamgage and the Elm River near the piezometer. Hydraulic gradients used in calculating hydraulic 

conductivity were based on average conditions of the Elm

River stage and piezometer water-level measurements for

May–September 2009.

Temperature Modeling Method

Natural variations in temperature can be used to track

the heat carried by flowing water. Tracing the transport of

heat leads to a better understanding of the magnitudes and 

mechanisms of stream/groundwater exchanges (Constantz and

Stonestrom, 2003).

A simple evaluation of the diurnal variation of water

temperature recorded at different depths may provide insight

into whether the stream is gaining or losing streamflow at

a specific location. The differences in diurnal temperature

variation for streams gaining and losing streamflow is illustrated in figure S5–2. Streams gaining flow from groundwater

will show a damped diurnal temperature pattern near the 

streambed; however, in a losing stream the water temperature at and below the streambed will vary similar to the

stream surface temperature pattern. The difference in altitude 

between the water table and stream stage determines whether 

the stream is gaining or losing flow. Sediments and aquifer

materials provide resistance to this flow, governing the rate

at which water travels between ground and surface environments (Constantz and Stonestrom, 2003). As the resistance

decreases (for example, coarser-grained sediments with more 

void space), the rate at which equilibrium is attained (water

table and stream stage altitudes are equal) increases. This 

Temperature

Temperature

Time Time

Time

Stage

Time

Stage

A B

Temperature

Depth below channel

GAINING

REACH

ADVECTION +

CONDUCTION

LOSING

REACH

ADVECTION +

CONDUCTION

Temperature

Winter Summer

Figure S5–2. Cross-section representation of relative temperature variation in A, gaining and B, losing stream reaches (modified 

from Constantz and Stonestrom, 2003).
Table S5–1. Piezometers completed in the Elm aquifer near the Elm River. [NAVD88, North American Vertical Datum of 1988; --, not determined] Station identification number Site identifier in downstream order Land surface altitude (feet above NAVD 88) Depth of piezometer below land surface (feet) Altitude of top of Elm aquifer (feet above NAVD 88) Maximum water- level altitude, May–September, 2009 (feet above NAVD 88) Minimum water- level altitude, May–September, 2009 (feet above NAVD 88) Mean water- level altitude, May–September, 2009 (feet above NAVD 88) Mean Elm River stage1 (feet above NAVD 88) Difference between mean Elm River stage and Elm aquifer water level (feet) Appr

alti

Elm 

b

(fee

NA

453954098310301 PZ6 1,323.2 11.0 1,313.7 1,318.7 1,318.0 1,318.3 1,317.4 0.9 1453921098294801 PZ1 1,318.9 14.5 1,305.9 1,318.8 1,317.0 1,317.5 1,314.7 2.8 1453711098280201 PZ7 1,313.3 19.0 1,295.8 1,310.9 1,310.3 1,310.5 1,306.7 3.8 1453622098284201 PZ8 1,311.7 24.0 1,289.2 1,307.9 1,307.4 1,307.6 1,306.7 0.9 1453515098280601 PZ9 1,313.4 24.0 1,290.8 1,307.6 1,307.5 1,307.5 1,306.6 0.9 1453508098273101 PZ5 1,313.9 18.0 1,297.4 1,305.4 1,303.2 1,304.3 1,306.6 -2.3 1453457098273301 PZ4 1,314.0 20.0 1,295.5 1,304.5 1,303.0 1,303.8 (2) -- 453501098271401 PZ3 1,318.3 19.6 1,300.2 1,305.1 1,302.4 1,303.6 1,306.5 -2.9 1453457098271401 PZ2 1,315.9 22.0 1,295.4 1,304.9 1,301.7 1,303.7 (2) -- 453436098260101 PZ10 1,310.9 19.0 1,293.4 1,311.2 1,310.2 1,310.8 (2) -- 453424098260101 PZ11 1,312.7 19.0 1,295.2 1,308.2 1,305.1 1,306.8 1,306.4 0.4 1

1Estimated from relation between stage height at U.S. Geological Survey streamgage 06471500 and surveyed river stage near the piezometer site. 2Piezometer set back from Elm River. 3Elm River incised into Elm aquifer with hydraulic connection limited by fine sediments deposited on river bottom.
84 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

equilibrium condition is referred to as a neutral reach, where no net gain or loss in either the 

surface-water or groundwater system happens.

Numerical modeling of energy (temperature) may be used to determine specific hydraulic

properties of the stream/groundwater system, such as hydraulic conductivity. Lapham (1989)

summarized the method to develop a model that describes vertical groundwater flow for a

gaining, neutral, or losing stream location. In this model, heat carried by advection (bulk fluid

movement of groundwater) and conduction (spontaneous transfer by direct contact) is represented by changes in temperature over time at different depth locations below the streambed.

Using known temperature measurements at specific depths below the stream, Darcy velocity

(flow through a unit area, also called specific discharge) can be calculated from the advective

transport portion of the model.

For one-dimensional, vertical isothermal flow of an incompressible fluid through homogenous, porous media, the general equation describing the simultaneous flow of fluid and heat in

the earth is (Lapham, 1989)

 k T

z c

T

z c

T

t z w w

∂

∂ − ∂

∂ = ∂

∂

2

2 ν ρ ρ 	 	 (S5A)

where

k 	 = thermal conductivity of the sediment-fluid matrix, in watts per meter per

degree Celsius;

T = temperature at any point z at any time t, in degrees Celsius;

cw 	 = volumetric heat capacity of the fluid, in joules per cubic meter per degree

Celsius;

	 ρw 	 = specific density of the fluid, unitless;

νz 	 = Darcian fluid velocity in the z direction, in meters per second;

c 	 = volumetric heat capacity of the sediment-fluid matrix, in joules per cubic

meter per degree Celsius; and

	 ρ 	 = wet-bulk specific gravity (density of the sediment-fluid matrix), unitless.

An explicit finite-difference approximation to equation S5A is (Lapham, 1989)

 T k t

ρc z

c z

k

T k t

ρc z

c z

k i

n w w z

i

+ n w w z = + −





 



 + − 1

2 1 2 1

2

1

2





 



ρ ν  ρ ν 



 



T + + −

k t

ρc z i T n

i

n

1 2 1 2 ( ) 



∆ ∆

∆ ∆

∆ ∆ ∆

∆

ρ v ρ v 	 (S5B)

Table S5–2. Darcy velocity, hydraulic gradient, and vertical hydraulic conductivity at temperature 

monitoring sites.

[--,	not	applicable]

Temperature 

logger site

Year 

monitored

Nearest 

piezometer 

site

Gaining 

or losing 

streamflow

Darcy velocity 

(feet per day)

Hydraulic 

gradient 

(feet per foot)

Effective vertical 

hydraulic 

conductivity 

(feet per day)

T1 2008 -- Gaining 0.30 -- --

T2 2008 -- Neutral 0.00 -- --

T2 2009 PZ8 Gaining 0.07 0.07 1.00

T3 2008 -- Gaining 0.50 -- --

T4 2008 -- Neutral 0.00 -- --

T5 2009 PZ1 Gaining 0.50 0.202 2.48

T6 2009 PZ3 Losing 0.06 0.433 0.14

T7 2009 PZ6 Gaining 0.25 0.187 1.34

T8 2009 PZ7 Gaining 0.10 0.352 0.28

T9 2009 PZ9 Gaining 0.10 0.062 1.62

T10 2009 -- Gaining 0.05 -- --

T11 2009 -- Gaining 0.06 -- --
Supplement 5. Estimating Vertical Hydraulic Conductivity of Sediments Separating the Elm River and Elm Aquifer using Temperature 85

where

Ti

n+1 = temperature at node i, in degrees Celsius at 

time step n+1, in seconds;

Ti-1

n = temperature at node i-1, in degrees Celsius 

at time step n, in seconds;

Ti+1

n = temperature at node i+1, in degrees Celsius 

at time step n, in seconds;

	 Δt = time increment between time steps, in 

seconds; and

	 Δz = spacing between nodes, in meters.

Temperature Modeling

One-dimensional temperature profiles were simulated

using the numerical solution presented in equation S5B

(Lapham, 1989). Using the observed Elm River time-series

data with a constant time step and known spacing between

observation nodes, the model was set up in a spreadsheet and

initialized with typical physical and thermal properties from 

literature (Stonestrom and Blasch, 2003). These properties

represent characteristics of the groundwater system in the 

immediate vicinity of the temperature loggers and are assumed

constant over the simulation period. These parameters were

varied simultaneously to minimize the sum of the absolute

error between the temperature at locations with simulated and 

observed temperatures below the streambed. After estimation of the physical properties of the subsurface sediments 

(table S5–3), the Darcy velocity of the groundwater/surfacewater system was used as a final calibration parameter of the

model for all sites (table S5–2). The observed and simulated

temperatures at the 11 sites along the Elm River are shown in

figures S5–3 through S5–14. Simulated temperature agreed

relatively well with observed temperature at known spatial and

temporal positions. The average absolute error in the temperature models ranged from 0.35 to 3.09 degrees Celsius.

Estimates of vertical seepage (Darcy velocity) from

simulation of temporal temperature gradients (table S5–2)

and hydraulic gradients (table S5–1) were used to estimate the

vertical hydraulic conductivity of the sediments separating the

Elm aquifer and the Elm River.

Hydraulic conductivity through sediments was estimated

using Darcy’s Law (Freeze and Cherry, 1979):

Q

A

v k h

L = = * 

(S5C)

where

Q = groundwater discharge, in cubic feet per 

day;

A = unit area, in square feet; 

v 	 = Darcy velocity, in feet per day;

k 	 = hydraulic conductivity, in feet per day;

	 ∆h/L = hydraulic gradient or change in hydraulic 

head through the length of the flow path, in

feet per foot. 

The hydraulic gradient, which is the change in hydraulic 

head through the length of the flow path, was the difference

between the Elm River stage and the hydraulic head in the

Elm aquifer.

Darcy velocities estimated from temperature modeling

(table S5–2) show that the Elm River experiences spatial variation in the groundwater/surface-water interactions throughout

the study area. The Elm River is gaining streamflow at a rate

of about 0.30 ft/d (through the streambed area) near site T1,

about neutral near site T2, and gaining streamflow at a rate

of about 0.50 ft/d near sites T3 and T5. The Elm River likely

is losing streamflow near site T6 at a rate of about 0.06 ft/d,

possibly explained by the proximity to the Eyestone Pit and

production wells. Vertical hydraulic conductivities ranged

from 0.14 to 2.48 ft/d (table S5–2).

Table S5–3. Thermal and physical properties used in the finite-difference 

approximation of energy transport.

[W/m-°C,	watts	per	meter	per	degree	Celsius;	J/m3-°C,	joules	per	cubic	meter	per	degree	

Celsius]

Property 

(equation S5A) Value Units

k 3.06 W/m-°C

cw 4,200,000 J/m3

-°C

ρw 1.0 Unitless

c 2,300,000 J/m3

-°C

ρ 2.2 Unitless
86 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

0

5

10

15

20

25

Temperature, in degrees Celsius

09/16/08 09/23/08 09/30/08 10/07/08 10/14/08 10/21/08 10/28/08 11/04/08 11/11/08 11/18/08 11/25/08

Gaining streamflow

Darcy velocity = 0.30 foot per day

Water temperature, 1.5 feet below Elm River

Simulated water temperature, 1.5 feet below Elm River

Water temperature, 6 feet below Elm River

Simulated water temperature, 6 feet below Elm River

EXPLANATION

Date (month/day/year)

Figure S5–3. Observed and simulated temperature for site T1.

0

5

10

15

20

25

Temperature, in degrees Celsius

09/16/08 09/23/08 09/30/08 10/07/08 10/14/08 10/21/08 10/28/08 11/04/08 11/11/08 11/18/08 11/25/08

Neutral streamflow

Darcy velocity = 0.00 foot per day

Water temperature, 1.5 feet below Elm River

Simulated water temperature, 1.5 feet below Elm River

Water temperature, 6 feet below Elm River

Simulated water temperature, 6 feet below Elm River

EXPLANATION

Date (month/day/year)

Figure S5–4. Observed and simulated temperature for site T2, 2008.
Supplement 5. Estimating Vertical Hydraulic Conductivity of Sediments Separating the Elm River and Elm Aquifer using Temperature 87

0

5

10

15

20

25

Temperature, in degrees Celsius

05/16/09 05/23/09 05/30/09 06/06/09 06/13/09 06/20/09 06/27/09 07/04/09 07/11/09 07/18/09 07/25/09 08/01/09 08/08/09 08/15/09 08/22/09 08/29/09

Gaining streamflow

Darcy velocity = 0.07 foot per day

Water temperature, 4.5 feet below Elm River

Simulated water temperature, 4.5 feet below Elm River

EXPLANATION

Date (month/day/year)

Figure S5–5. Observed and simulated temperature for site T2, 2009.

8

9

10

11

12

13

Temperature, in degrees Celsius

10/04/08 10/11/08 10/18/08 10/25/08 11/01/08 11/08/08 11/15/08 11/22/08 11/29/08

Gaining streamflow

Darcy velocity = 0.50 foot per day

Water temperature, 1 foot below Elm River

Simulated water temperature, 1 foot below Elm River

Water temperature, 4 feet below Elm River

Simulated water temperature, 4 feet below Elm River

EXPLANATION

Date (month/day/year)

Figure S5–6. Observed and simulated temperature for site T3.
88 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota Temperature, in degrees Celsius

Date (month/day/year)

10/04/08 10/11/08 10/18/08 10/25/08 11/01/08 11/08/08 11/15/08 11/22/08

Neutral streamflow

Darcy velocity = 0.00 foot per day

Water temperature, 2 feet below Elm River

Simulated water temperature, 2 feet below Elm River

Water temperature, 4 feet below Elm River

Simulated water temperature, 4 feet below Elm River

EXPLANATION

0

5

10

15

20

25

Figure S5–7. Observed and simulated temperature for site T4.

Temperature, in degrees Celsius

Date (month/day/year)

05/09/09 05/16/09 05/23/09 05/30/09 06/06/09 06/13/09 06/20/09 06/27/09 07/04/09 07/11/09 07/18/09 07/25/09

Gaining streamflow

Darcy velocity = 0.50 foot per day

Water temperature, 1 foot below Elm River

Simulated water temperature, 1 foot below Elm River

Water temperature, 4 feet below Elm River

Simulated water temperature, 4 feet below Elm River

EXPLANATION

0

5

10

15

20

25

Figure S5–8. Observed and simulated temperature for site T5.
Supplement 5. Estimating Vertical Hydraulic Conductivity of Sediments Separating the Elm River and Elm Aquifer using Temperature 89

0

5

10

15

20

25

Temperature, in degrees Celsius

05/09/0905/16/0905/23/09

05/30/09

06/06/09

06/13/0906/20/0906/27/0907/04/0907/11/0907/18/0907/25/0908/01/0908/08/0908/15/0908/22/0908/29/09

Losing streamflow

Darcy velocity = 0.06 foot per day

Water temperature, 1.5 feet below Elm River

Simulated water temperature, 1.5 feet below Elm River

Water temperature, 6 feet below Elm River

Simulated water temperature, 6 feet below Elm River

EXPLANATION

Date (month/day/year)

Figure S5–9. Observed and simulated temperature for site T6.

Temperature, in degrees Celsius

05/23/09 05/30/09 06/06/09 06/13/09 06/20/09 06/27/09 07/04/09 07/11/09 07/18/09 07/25/09 08/01/09 08/08/09 08/15/09 08/22/09 08/29/09

Gaining streamflow

Darcy velocity = 0.25 foot per day

Water temperature, 3 feet below Elm River

Simulated water temperature, 3 feet below Elm River

EXPLANATION

5

7

9

11

13

15

Date (month/day/year)

Figure S5–10. Observed and simulated temperature for site T7.
90 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

0

5

10

15

20

25

Temperature, in degrees Celsius

05/16/09 05/23/09 05/30/09 06/06/09 06/13/09 06/20/09 06/27/09 07/04/09 07/11/09 07/18/09 07/25/09 08/01/09 08/08/09 08/15/09 08/22/09 08/29/09

Gaining streamflow

Darcy velocity = 0.10 foot per day

Water temperature, 1.5 feet below Elm River

Simulated water temperature, 1.5 feet below Elm River

Water temperature, 6 feet below Elm River

Simulated water temperature, 6 feet below Elm River

EXPLANATION

Date (month/day/year)

Figure S5–11. Observed and simulated temperature for site T8.

0

5

10

15

20

25

Temperature, in degrees Celsius

05/30/0906/06/09

06/13/0906/20/09

06/27/0907/04/09

07/11/09

07/18/09

07/25/0908/01/09

08/08/0908/15/09

08/22/09

Gaining streamflow

Darcy velocity = 0.10 foot per day

Water temperature, 1.5 feet below Elm River

Simulated water temperature, 1.5 feet below Elm River

Water temperature, 6 feet below Elm River

Simulated water temperature, 6 feet below Elm River

EXPLANATION

Date (month/day/year)

Figure S5–12. Observed and simulated temperature for site T9.
Supplement 5. Estimating Vertical Hydraulic Conductivity of Sediments Separating the Elm River and Elm Aquifer using Temperature 91

0

5

10

15

20

25

Temperature, in degrees Celsius

Gaining streamflow

Darcy velocity = 0.05 foot per day

Water temperature, 1.5 feet below Elm River

Simulated water temperature, 1.5 feet below Elm River

Water temperature, 6 feet below Elm River

Simulated water temperature, 6 feet below Elm River

EXPLANATION

05/30/0906/06/0906/13/09

06/20/09

06/27/09

07/04/0907/11/0907/18/0907/25/0908/01/0908/08/0908/15/0908/22/0908/29/0909/05/0909/12/09

Date (month/day/year)

Figure S5–13. Observed and simulated temperature for site T10.

0

5

10

15

20

25

Temperature, in degrees Celsius

Gaining streamflow

Darcy velocity = 0.06 foot per day

Water temperature, 1.5 feet below Elm River

Simulated water temperature, 1.5 feet below Elm River

Water temperature, 6 feet below Elm River

Simulated water temperature, 6 feet below Elm River

EXPLANATION

05/30/0906/06/0906/13/09

06/20/09

06/27/09

07/04/0907/11/09

07/18/09

07/25/09

08/01/0908/08/0908/15/09

08/22/0908/29/09

09/05/09

09/12/09

Date (month/day/year)

Figure S5–14. Observed and simulated temperature for site T11.
92 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Supplement 6. Analysis of Recharge with a Soil-WaterBalance Method

This section describes the use of a soil-water-balance (SWB) method, using the SWB

program by Westenbroek and others (2010), to determine the amount of recharge available to

the Elm aquifer. The infiltration rate used in recharge calculations is presented in table S6–1

according to soil type and till thickness overlying the Elm aquifer. The distribution of soil types

is presented in figure S6–1.

Table S6–1. Infiltration rates assigned by soil type and till thickness.

[>, greater than; --, not applicable]

Till thickness, 

in feet

Infiltration rate for soil type, in inches per day 

A B BC C CD D

0–10 7.20 3.60 2.40 1.20 0.72 0.24

>10–20 2.00 1.00 1.00 1.00 0.72 0.24

>20–30 -- 0.50 0.50 0.50 0.50 0.24

>30 -- 0.01 0.01 0.01 0.01 0.01

The SWB program makes use of daily precipitation and temperature data with land

use, soil type, root depth, and runoff flow direction to calculate runoff, evapotranspiration, and recharge. The SWB program can account for frozen ground, snowfall, snowmelt,

and the dependency of recharge on the timing and spatial distribution of precipitation. The 

modified Thornthwaite-Mather soil-water accounting is used to calculate recharge by using

equation S6A:

recharge = (precipitation + snowmelt + inflow) – (interception + outflow + ET) – ∆soil moisture (S6A)

where

precipitation, snowmelt, and inflow are sources; 

interception, outflow, and evapotranspiration (ET) are sinks; and

∆soil moisture is the change in soil moisture as the amount of water added to or lost from 

the soil, with the maximum set by the holding capacity of the soil and the 

minimum set by the wilting point.

Runoff is calculated through the following equation (Westenbroek and others, 2010):

 R

P I

P S I

a

max a

= ( ) −

( ) + − [ ]

2

 (S6B)

where

P is greater than Ia, in inches;

R = runoff, in inches;

P = daily precipitation, in inches;

Ia = initial abstraction, the amount of precipitation that must fall before any 

runoff is generated, in inches; and

Smax = maximum soil-moisture holding capacity, in inches.
Supplement 6. Analysis of Recharge with a Soil-Water-Balance Method 93

Initial abstraction (Ia) is related to maximum soil-moisture 

holding capacity (Smax) through the following equation (Westenbroek and others, 2010):

 (S6C)

The maximum soil-moisture holding capacity (Smax) is based 

on the Natural Resources Conservation Service curve number

(CN; Curve Number Work Group, 2004) for a soil by using the

following equation (Westenbroek and others, 2010):

I S a max = 0 2.

S

CN max = 



 



 − 1000 10 (S6D)

Data from seven National Oceanic and Atmospheric

Administration precipitation stations (Aberdeen Regional

Airport, 390020; Aberdeen 2E, 390020; Bath 1NE, 390553;

Columbia 1S, 391884; Columbia 8N, 391873; Westport,

399138; and Westport 1N, 399136) were used for the climate

inputs to the SWB program (National Climate Data Center,

2011; fig. 1). The Aberdeen Regional Airport and Columbia

8N stations had temperature data for 1975–2009, and the

temperatures were averaged for each day unless one station

did not have data for that particular day (National Climate

Data Center, 2011). When the temperature was only recorded

at one station, that value was used in place of a temperature

averaged between the two stations. A third station, Aberdeen 2E, had been assigned the same station number as the

airport and produced duplicate data over part of the period

of record (National Climate Data Center, 2011). Temperature and precipitation data were only used from this station 

when no data were available from the airport. Precipitation

data were averaged from all stations with a record of the

given day to provide one value that could be entered into the

SWB program. The precipitation data were in water equivalent inches when the precipitation came in the form of snow 

(National Climate Data Center, 2011), and the SWB program

used temperature data to determine when precipitation was 

snow (Westenbroek, 2010). The Hargreaves-Samani method of

evapotranspiration calculation was chosen for use in the SWB

program because only minimum, maximum, and average

temperature and precipitation data were required on a daily 

time step (Westenbroek and others, 2010).

The flow direction grid was created from the 10-m (33-ft)

digital elevation model of the study area (U.S. Geological

Survey, 2006). The SWB program only allows runoff to flow

in one direction from a cell (Westenbroek and others, 2010),

so cells that could have multiple runoff directions from the

digital elevation model were examined and modified. If the

cell allowed runoff into multiple cells along one direction, 

the flow direction was set to the central or most representative cell. If the runoff could flow in opposite directions, the

cell was assigned an arbitrary number that was used for all 

“depression” cells. All depressions were allowed to infiltrate

water from runoff the day the runoff was generated, but any 

ponding was removed at the start of the next day (Westenbroek and others, 2010). The continuous frozen ground index

(in degrees Celsius-days) was used to increase the runoff 

resulting from precipitation or snowmelt that happens while 

the ground is frozen (Westenbroek and others, 2010). Antecedent moisture conditions are considered from the previous

5 days (Westenbroek and others, 2010).

The hydrologic soil groups were assigned as A, B,

BC, C, CD, and D on the basis of soil survey data (Natural

Resources Conservation Service, 2009a) with similar additional soil groups in the SWB program used to account for

the thickness of till above the aquifer. Soil group A has the

highest infiltration rate, and soil group D has the lowest

infiltration rate (Natural Resources Conservation Service,

2009a). The infiltration rate of combination soil groups was

calculated from the average of the two soil groups that were

mixed (table S6–1).

Till thicknesses were calculated as the difference between

land surface and the top of the Elm aquifer. The modified infiltration rates were selected to decrease with greater

till thickness, which better accounted for the impermeable

character of glacial till. The till thickness intervals used in

creating the modified soil groups were set as 0 to 10 ft, greater

than 10 to 20 ft, greater than 20 to 30 ft, and greater than 30 ft

(table S6–1). A maximum infiltration rate was estimated on

the basis of glacial till thickness overlying the Elm aquifer

and the range of vertical hydraulic conductivity for glacial till

(table 3). Emmons (1990) used a linear decrease in recharge

from 7.0 to 0 in/yr as till thickness increased from 0 to 50 ft.

The low recharge values coincide with areas where glacial till

was thickest. The SWB program also uses a flow-direction

algorithm that accumulates recharge that moves towards

topographically low areas, resulting in the higher values of

recharge.

Land-cover data for 2006 were obtained from the

Multi-Resolution Land Characteristics Consortium (2011)

as 30-m (98-ft) raster data (fig. 3). The most prevalent land

cover was selected for each model cell because about four

land-cover raster cells were in each model cell. Most of the

model grid had one or two land-cover types as designated by

the land-cover raster (Multi-Resolution Land Characteristics

Consortium, 2011). Each land cover was assigned values for

interception storage in the growing and dormant seasons. The 

growing season was set as the period from May 1 to September 30. Interception storage values of zero were assigned for

the dormant season, and values for the growing season ranged

from 0 to 0.11 inch (table S6–2). Land cover and soil group

were assigned to every cell in the model, and each combination of land cover and soil group was assigned a curve number

and depth of root zone.

The curve number was identical for every soil within the

same hydrologic soil group because till thickness has no effect

on the curve number. Curve numbers were assigned based on

classifications in the National Engineering Handbook (Curve
94 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Base from U.S. Geological Survey digital data, 1995, 1:100,000

Universal Transverse Mercator projection, Zone 14 North

EXPLANATION

Soil type

A

B

BC

C

CD

D

0 2 4 MILES

0 2 4 KILOMETERS

£¤281

45 35'

45 30'

45 40'

98 30' 98 22'30''

R. 64 W. R. 63 W. R. 62 W.

T. 123 N.

T. 124 N.

T. 125 N.

Columbia

Westport

Elm River

Foot Creek

James River

Moccasin Creek

Foot Cr

COUNTY ROAD 16

Aberdeen

Figure S6–1. Soil type as defined for recharge calculations in soil-water-balance method (based on 

soil survey data from Natural Resources Conservation Service, 2009a).
Supplement 6. Analysis of Recharge with a Soil-Water-Balance Method 95

Number Work Group, 2004). Developed land covers were

given curve numbers calculated as the average of relevant

classifications to the known land covers (for example, gravel

roads, paved roads with open ditches, and 1⁄4-acre residential)

(Curve Number Work Group, 2004). Wetland land covers were

assigned curve numbers from Westenbroek and others (2010)

because the National Engineering Handbook did not include

wetlands in the types of land covers discussed.

The root zone depths were assigned as identical for every

soil (table S6–2), but varied by land cover using data compiled

by Canadell and others (1996) and Westenbroek and others

(2010) because data were not sufficient to further constrain

the inputs; however, Thornthwaite and Mather (1957) determined that plants typically have deeper roots in sandy soils

than in clayey soils (Westenbroek and others, 2010). The

SWB program uses available water capacity for each root

zone category to calculate the maximum amount of water that 

the soil can hold in storage (Westenbroek and others, 2010).

The Natural Resources Conservation Service soil survey for

Brown County contained available water capacity ranges for

each horizon in every soil (Natural Resources Conservation

Service, 2009b). The soils were lumped according to hydrologic group, so the available water capacity data were averaged to generate one value per hydrologic group.

Table S6–2. Interception storage values and depth of root 

zone assigned by land-cover category.

Land-cover category

Interception 

storage, 

in inches

Depth of 

root zone, 

in feet

Open water 0.00 0.0

Developed, open space 0.08 2.0

Developed, low intensity 0.08 2.0

Developed, medium intensity 0.06 2.0

Developed, high intensity 0.06 2.0

Barren land 0.00 2.0

Deciduous forest 0.09 4.5

Evergreen forest 0.11 5.5

Shrub or scrub 0.06 3.5

Herbaceous grassland 0.09 4.0

Pasture/hay 0.09 4.0

Cultivated crops 0.09 3.5

Woody wetlands 0.05 4.5

Emergent herbaceous wetlands 0.00 2.0
96 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Supplement 7. Water-Level Data for Generalized Potentiometric Surface of Elm 

Aquifer

Table S7–1. Water-level data for generalized average potentiometric surface of Elm Aquifer (1975–2009).

[--, not applicable]

Site 

identifier 

(fig. 18)

Station 

identification 

number

Local number

Earliest 

or single 

water-level 

date

Earliest 

or single 

water-level 

altitude1

Other 

identifier

Period of record 

for wells with 

synoptic 

water-level 

measurements

Estimated

average 

water-level 

altitude 

(1975–2009)1

1 454010098314402 125N64W 3CAA2 08/01/1970 1,319 -- -- 1,319

2 453949098321601 125N64W10BBBB 06/01/1984 1,337 -- -- 1,340

3 453954098310301 125N64W02CCBB 06/05/2009 1,318 PZ6 2009 1,317

4 453921098294801 125N64W12BCCA 05/21/2009 1,318 PZ1 2009 1,316

5 453944098283801 125N64W12AAA 08/19/1981 1,358 -- -- 1,358

6 453904098281901 125N63W 7CCA 08/20/1981 1,317 -- -- 1,321

7 453923098271601 125N63W 8BCB 06/03/1983 1,338 -- -- 1,339

8 453856098263901 125N63W 8DCCC 08/01/1955 1,334 -- -- 1,333

9 453948098260601 125N63W 5DDDD 08/01/1955 1,344 -- -- 1,343

10 454037098245201 125N63W04AAAA 06/07/1977 1,323 BN–77N 1977–2009 1,324

11 453853098245201 125N63W16AAAA 06/07/1977 1,328 BN–77M 1977–2009 1,327

12 453837098224001 125N64W14ADB 04/11/1983 1,286 -- -- 1,287

13 453957098214101 125N63W 1DCC 10/31/1983 1,290 -- -- 1,290

14 453800098222002 125N63W13CCCC2 10/11/1974 1,291 MM1 1974–85 1,292

15 453734098295201 125N64W23DAA 08/01/1970 1,340 -- -- 1,340

16 453911098280201 125N63W19CDDD 06/05/2009 1,311 PZ7 2009 1,308

17 453616098321201 125N64W34BBB 08/01/1970 1,356 -- -- 1,356

18 453635098305701 125N64W26CBC 08/01/1970 1,339 -- -- 1,339

19 453622098284201 125N64W25DDAD 06/05/2009 1,308 PZ8 2009 1,307

20 453620098275801 125N63W30CDDD 09/01/1968 1,303 -- -- 1,303

21 453623098271601 125N63W29CCCC 06/07/1977 1,330 BN–77L 1977–2009 1,336

22 453639098195601 125N62W30DAA 07/01/1951 1,282 -- -- 1,276

23 453520098320501 124N64W04AAAA1 05/20/1982 1,340 BN–82E 1982–2009 1,348

24 453515098280601 124N63W06BACA 07/07/2009 1,308 PZ9 2009 1,307

25 453508098273101 124N63W06ADBB 06/05/2009 1,303 PZ5 2009 1,302

26 453457098273301 124N63W06DABB 06/05/2009 1,303 PZ4 2009 1,302

27 453524098222301 125N63W35DDDD 08/01/1968 1,293 -- -- 1,290

28 453438098314501 124N64W 3CDC 08/01/1970 1,331 -- -- 1,331

29 453437098272401 124N63W06DDBD 09/19/2005 1,300 -- -- 1,297

30 453430098264501 124N63W08ABBA 05/12/2008 1,306 A–2 2008–09 1,301

31 453430098262901 124N63W08ABBA 05/12/2008 1,307 A–1 2008–09 1,303

32 453436098260101 124N63W05DDAD 07/06/2009 1,310 PZ10 2009 1,306

33 453424098260101 124N63W08AADA 08/01/2009 1,305 PZ11 2009 1,304

34 453424098271701 124N63W 7AAD 09/01/1967 1,299 -- -- 1,298
Supplement 7. Water-Level Data for Generalized Potentiometric Surface of Elm Aquifer 97

Table S7–1. Water-level data for generalized average potentiometric surface of Elm Aquifer (1975–2009).—Continued

[--, not applicable]

Site 

identifier 

(fig. 18)

Station 

identification 

number

Local number

Earliest 

or single 

water-level 

date

Earliest 

or single 

water-level 

altitude1

Other 

identifier

Period of record 

for wells with 

synoptic 

water-level 

measurements

Estimated 

average 

water-level 

altitude 

(1975–2009)1

35 453414098265701 124N63W08BCAA 12/03/2004 1,303 -- -- 1,300

36 453410098264601 124N63W08BDAC 12/02/2004 1,304 -- -- 1,301

37 453359098263801 124N63W08AADD 12/02/2004 1,304 -- -- 1,300

38 453351098264501 124N63W 8DAC	 10/30/1998 1,307 -- -- 1,306

39 453351098261701 124N63W 8DACC	 10/30/1998 1,306 -- -- 1,305

40 453439098243201 124N63W 3CCAB	 09/01/1967 1,300 -- -- 1,299

41 453428098194202 124N62W08BBBB2 06/09/1982 1,283 BN–82K 1982–2009 1,293

42 453346098343101 124N64W 8CCC	 08/01/1970 1,361 -- -- 1,361

43 453340098311001 124N64W10DDD 08/01/2007 1,338 R0–00–41 -- 1,337

44 453320098305902 124N64W15ADD2 08/01/1970 1,328 -- -- 1,328

45 453341098255801 124N63W16BBCB 10/30/1998 1,306 -- -- 1,305

46 453336098252401 124N63W16BAAC 10/30/1998 1,308 -- -- 1,307

47 453345098243901 124N63W10CCC 02/01/1967 1,296 -- -- 1,295

48 453312098244401 124N63W15CBBB 10/05/1974 1,296 MM3 1974–85 1,296

49 453402098183201 124N62W08ADDD 10/09/1974 1,287 MM2 1974–85 1,290

50 453254098340401 124N64W17CDD 07/27/1982 1,349 -- -- 1,354

51 453254098304901 124N64W14CCC 08/01/1970 1,326 -- -- 1,326

52 453254098301201 124N64W14DCC 08/01/1970 1,323 -- -- 1,323

53 453246098294501 124N64W23AAAA 07/30/2007 1,326 R2–00–42 2007–2009 1,326

54 453247098260103 124N63W17DDDD3 08/23/1999 1,305 MM5 1999–2009 1,307

55 453246098243901 124N63W22BBB 07/01/1955 1,294 -- -- 1,294

56 453200098343901 124N64W20CCCB 08/01/2007 1,350 R2–00–51 2007–2009 1,347

57 453155098330801 124N64W28BBA 08/01/1970 1,329 -- -- 1,329

58 453203098323801 124N64W21DCCD 09/30/1987 1,329 -- -- 1,332

59 453202098320301 124N64W22CCC 11/16/1982 1,322 -- -- 1,328

60 453136098320302 124N64W27BCC2 08/01/1970 1,324 -- -- 1,324

61 453159098282401 124N63W19CCCC 09/01/1967 1,305 -- -- 1,304

62 453154098255301 124N63W28BBB 07/01/1955 1,296 -- -- 1,292

63 453214098232501 124N63W23CBC 07/01/1955 1,292 -- -- 1,292

64 453153098232901 124N63W23CCCD 07/31/2007 1,301 -- -- 1,299

65 453147098222101 124N63W26AAD 09/01/1967 1,294 -- -- 1,295

66 453103098341301 124N64W32BAB 08/01/1970 1,321 -- -- 1,321

67 453109098332702 124N64W29DDD2 08/01/1970 1,324 -- -- 1,324

68 453103098310801 124N64W34AAB 08/01/1970 1,320 -- -- 1,320

69 453131098294203 124N64W26DAAA3 08/01/1970 1,312 -- -- 1,311

70 453109098294501 124N64W26DDD 08/01/1970 1,311 -- -- 1,313

71 453116098292601 124N64W25CCA 08/01/1970 1,306 -- -- 1,305

72 453134098271701 124N63W30ADD 07/01/1955 1,298 -- -- 1,294
98 Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota

Table S7–1. Water-level data for generalized average potentiometric surface of Elm Aquifer (1975–2009).—Continued

[--, not applicable]

Site 

identifier 

(fig. 18)

Station 

identification 

number

Local number

Earliest 

or single 

water-level 

date

Earliest 

or single 

water-level 

altitude1

Other 

identifier

Period of record 

for wells with 

synoptic 

water-level 

measurements

Estimated

average 

water-level 

altitude 

(1975–2009)1

73 453103098255701 124N63W28CCCC 05/20/1982 1,297 BN–82F 1982–2009 1,295

74 453128098243901 124N63W27CBB 07/01/1955 1,290 -- -- 1,286

75 453054098243601 124N63W34BB 06/02/1983 1,281 -- -- 1,283

76 453055098233501 124N63W34AAD 07/01/1955 1,291 -- -- 1,291

77 453105098183002 124N62W28CCCC2 08/01/1967 1,279 -- -- 1,274

78 452950098321502 123N64W 4ADDC2 03/01/1969 1,307 -- -- 1,307

79 452923098313301 123N64W 3CDDD 03/01/1926 1,313 -- -- 1,309

80 453016098293601 124N64W36CCDB 07/31/2007 1,309 -- -- 1,305

81 452955098271401 123N63W 6ADAD 06/01/1949 1,292 -- -- 1,291

82 453012098255602 124N63W33CCCC2 05/01/1956 1,288 -- -- 1,284

83 452948098233201 123N63W 3ADDD 06/01/1949 1,294 -- -- 1,290

84 452846098295401 123N64W11DAC 06/01/1949 1,303 -- -- 1,301

85 452851098282101 123N63W 7CBB 07/01/1949 1,292 -- -- 1,291

86 452915098271501 123N63W08BBBB 09/06/1977 1,284 BN–77V 1977–2009 1,293

87 452917098255301 123N63W 9BBB 06/01/1949 1,286 -- -- 1,284

88 452924098244902 123N63W 4DDD2 06/01/1949 1,293 -- -- 1,287

89 452830098230101 123N63W11CDDC 07/01/1968 1,291 -- -- 1,288

90 452948098194301 123N62W 5BCC 06/01/1949 1,284 -- -- 1,280

91 452928098194401 123N62W05CBCC 10/09/1974 1,281 MM4 1974–85 1,283

1

Datum is North American Vertical Datum of 1988.

Publishing support provided by:

Rolla Publishing Service Center

For more information concerning this publication, contact:

Director, USGS South Dakota Water Science Center

1608 Mt. View Road

Rapid City, SD 57702

(605) 394–3200

Or visit the South Dakota Water Science Center Web site at:

http://sd.water.usgs.gov
Back cover.

Top left: Installing temperature probe along the Elm River.

Top right: Surveying altitude of a piezometer completed in the Elm aquifer.

Lower bottom: Collecting direct-current electrical resistivity data.
Marini and others—Conceptual and Numerical Models of the Glacial Aquifer System North of Aberdeen, South Dakota—SIR 2012–5183

Printed on recycled paper