U.S. Department of the Interior

U.S. Geological Survey

Open-File Report 2008–1133

In cooperation with the Lac Courte Oreilles Band of Lake Superior Chippewa

Simulation of Contributing Areas and Surface-Water Leakage 

to Potential Replacement Wells Near the Community of 

New Post, Sawyer County, Wisconsin, by Means of a

Two-Dimensional Ground-Water-Flow Model

Simulation of Contributing Areas and 

Surface-Water Leakage to Potential 

Replacement Wells Near the Community 

of New Post, Sawyer County, Wisconsin, 

by Means of a Two-Dimensional GroundWater-Flow Model

By Paul F. Juckem and Randall J. Hunt

In cooperation with the Lac Courte Oreilles Band of Lake Superior Chippewa

Open-File Report 2008–1133

U.S. Department of the Interior

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

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2008

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Suggested citation:

Juckem, P.F., and Hunt, R.J., 2008, Simulation of contributing areas and surface-water leakage to potential replacement wells near the community of New Post, Sawyer County, Wisconsin, by means of a two-dimensional groundwater-flow model: U.S. Geological Survey Open-File Report 2008–1133, 12 p.
iii

Contents

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

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

Purpose and Scope ..............................................................................................................................1

Physical Setting.....................................................................................................................................1

Data Sources.........................................................................................................................................2

Assumptions and Limitations..............................................................................................................2

Methods...........................................................................................................................................................2

Conceptual Model..........................................................................................................................................2

Refinement of the Model to Simulate Possible Replacement Wells.....................................................3

Results of Simulating Potential Replacement Wells................................................................................3

Discussion.......................................................................................................................................................4

Summary........................................................................................................................................................11

References Cited..........................................................................................................................................11

Figures

1–6. Maps showing simulated contributing areas for potential replacement wells

pumping 30,000 gallons per day at specified locations and resistances to vertical

flow along the Chippewa Flowage:

1. Well at borehole BH-2, low resistance (0.005 day) (scenario 1)..................................5

2. Well at borehole BH-2, high resistance (5 days) (scenario 2)......................................6

3. Replacement well B, low resistance (0.005 day) (scenario 3). ....................................7

4. Replacement well B, high resistance (5 days) (scenario 4). ........................................8

5. Replacement well C, low resistance (0.005 day) (scenario 5)......................................9

6. Replacement well C, high resistance (5 days)(scenario 6). .......................................10
iv

Conversion Factors

Multiply By To obtain

Length

foot (ft) 0.3048 meter (m)

Rate

gallon per day (gal/d) 0.003785 cubic meter per day (m3

/d)

Hydraulic conductivity*

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

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

(NAVD 88).

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

*Hydraulic conductivity: The standard unit for hydraulic conductivity is cubic foot per day per 

square foot of aquifer cross-sectional area (ft3/d/ft2). In this report, the mathematically reduced 

form, foot per day (ft/d), is used for convenience.
Simulation of Contributing Areas and Surface-Water 

Leakage to Potential Replacement Wells Near the 

Community of New Post, Sawyer County, Wisconsin, by 

Means of a Two-Dimensional Ground-Water-Flow Model

By Paul F. Juckem and Randall J. Hunt

Abstract

A two-dimensional, steady-state ground-water-flow 

model of the shallow ground-water-flow system near the 

community of New Post, Sawyer County, Wis., was refined 

from an existing model of the area. Hydraulic-conductivity 

and recharge values were not changed from the existing model 

for the scenario simulations described in this report. Rather, 

the model was refined by adding detail along the Chippewa 

Flowage and then was used to simulate contributing areas 

for three potential replacement wells pumping 30,000 gallons per day. The model also was used to simulate potential 

surface-water leakage out of the Chippewa Flowage captured 

by replacement-well pumping. A range in resistance to vertical 

ground-water flow was simulated along the Chippewa Flowage for each potential replacement-well location to bound 

the potential effects of representing three-dimensional flow 

with a two-dimensional model. Results indicate that pumping 

from a replacement well sited about 130 feet from the Chippewa Flowage could capture as much as 39 percent of the 

total pumping from the flowage. Pumping from either of two 

potential replacement wells sited at least 400 feet from the 

Chippewa Flowage did not induce surface-water leakage out 

of the flowage regardless of the resistance applied along the 

flowage for simulations described in this report.

Introduction

The community of New Post, Wis., is interested in drilling a new water-supply well to replace two existing wells. The 

Lac Courte Oreilles Band of Lake Superior Chippewa (LCO) 

Public Works Department and the Indian Health Service (IHS) 

are concerned about the potential for a new well to capture 

surface water from the Chippewa Flowage. A previous study 

by the USGS (Juckem and Hunt, 2007), in cooperation with 

the LCO, evaluated the shallow ground-water-flow system 

near Grindstone Creek and the community of New Post on the 

LCO reservation. Simulations with the analytic element model 

developed by Juckem and Hunt (2007) were previously used 

to evaluate contributing areas (the land-surface area that contributes ground-water recharge to the well) and the potential to 

capture surface water for the existing wells and two potential 

replacement wells. Additional simulations were recently 

requested by LCO and IHS to evaluate contributing areas and 

surface-water leakage for a higher pumping rate at one of the 

previously evaluated potential replacement wells and at two 

additional well locations.

Purpose and Scope

This report describes the refinement and results of twodimensional, steady-state, ground-water-flow modeling of the 

shallow hydrologic system near the community of New Post, 

Sawyer County, Wis. The purpose of these simulations was to 

estimate the ground-water contributing areas for three potential replacement wells and evaluate the potential of the wells to 

capture surface-water leakage out of the Chippewa Flowage. 

The model theory, construction, and calibration of the underlying regional model are fully described by Juckem and Hunt 

(2007). No additional ground-water-level or streamflow data 

have been collected in the area of interest, and the underlying 

model has not been recalibrated. 

Physical Setting

The regional and local settings are described by Juckem 

and Hunt (2007); important features of the local setting are 

briefly described here. The community of New Post is in central Sawyer County along the southern shores of the Chippewa 

Flowage. The ground-water-flow system near New Post is 

bounded by the Chippewa Flowage to the north and a crystalline bedrock mound buried by glacial sand and gravel to the 

south. Boreholes indicate an increase in aquifer thickness from 
2 Simulation of Contributing Areas and Surface-Water Leakage to Potential Replacement Wells, New Post, Wis.

the crystalline mound northward toward the Chippewa Flowage. The sand and gravel aquifer has a relatively high horizontal hydraulic conductivity (Tyrolt, 2006; Juckem and Hunt, 

2007) and no laterally extensive confining beds. 

Data Sources

No new data were incorporated into this effort; data 

sources used to refine the model were the same as those used 

in the original study by Juckem and Hunt (2007).

Assumptions and Limitations

Given the relatively coarse nature of the unconsolidated sediments, relatively high net annual precipitation, and 

ground-water levels being near the flowage stage, the groundwater and surface-water systems were assumed to have a close 

hydrologic connection in the modeled area. Therefore, elevations of surface-water features were assumed to be representative of the ground-water system. A two-dimensional model 

was assumed to be appropriate for the larger model domain 

because the ground-water-flow system is thin and areally 

extensive. However, because two-dimensional models may 

not accurately represent the ground-water-flow system within 

two to three aquifer thicknesses of a surface-water feature 

(Haitjema, 1995, 2006; Hunt and others, 2003), simulated 

ground-water gradients near surface-water features and the 

amount of ground-water/surface-water exchange should be 

considered only approximate. In addition, all replacement 

wells were assumed to be open to the full saturated thickness of the aquifer. Finally, steady-state simulations were also 

assumed appropriate for this study. Steady-state simulations 

can be expected to result in an estimate of the higher range of 

system response to a hydrologic stress because they are not 

mitigated by ground-water release from storage.

Methods

An analytic element ground-water-flow model, developed 

with the computer program GFLOW (Haitjema, 1995) was 

used to simulate the ground-water system and its interaction 

with surface-water features. A complete description of analytic 

elements is beyond the scope of this report, but a brief description follows. (Hunt (2006) gives a review of applications of the 

analytic element method, and Haitjema (1995) discusses the 

underlying concepts and mathematics of the method in detail.) 

An infinite aquifer is assumed in analytic element modeling. To construct an analytic element model, features important for controlling ground-water flow (for example, wells and 

surface-water features) are entered as mathematical elements 

or strings of elements. The amount of detail specified for the 

features depends on distance from the area of interest. Each 

element is represented by an analytic solution. The effects of 

these individual solutions are added together to form a solution 

for any location in the simulated ground-water-flow system. 

In the GFLOW code used here, the analytic elements are two 

dimensional and are used only to simulate steady-state conditions (water levels that do not vary with time). The analytic 

element method and comparisons of analytic element to finitedifference numerical model techniques have been discussed by 

others (Haitjema, 1995; Hunt and Krohelski, 1996; Hunt and 

others, 1998, 2003).

Hydraulic conductivity and recharge values calibrated by 

Juckem and Hunt (2007) were not changed for the simulations 

described in this report. Streambed resistance for the Chippewa Flowage was varied over a range of reasonable values 

to approximate a range in resistance to vertical ground-water 

flow, but streambed resistance for all other surface-water features was set to the original values of Juckem and Hunt (2007). 

Likewise, the width parameter (Haitjema, 1995, 2005; Hunt 

and others, 2003) was computed automatically by the GFLOW 

model for the Chippewa Flowage based on the local transmissivity and resistance, but the values of Juckem and Hunt 

(2007) were used for all other surface-water features. A range 

of values for streambed resistance for the Chippewa Flowage 

was used to simulate a range of possible surface-water capture 

for the simulated potential replacement wells.

Conceptual Model

A conceptual model is a simplification of the hydrologic system into important component parts, and it forms 

the framework for computer simulations. This simplification 

is necessary because inclusion of all of the hydrogeologic 

complexities into a model is not feasible. Steps in the development of the conceptual model include (1) characterization of 

the aquifer(s), (2) identification of sources and sinks of water, 

and (3) identification and delineation of hydrologic boundaries 

in the area of interest. The conceptual model of the hydrologic 

system near the community of New Post was described by 

Juckem and Hunt (2007); it has been refined for the scenarios 

described in this report, with the important features described 

below.

The aquifer consists of glacial sediments that were 

deposited directly on top of crystalline rocks in the New Post 

area. Thickness of the glacial sediments is varied and related 

in part to the elevation of the underlying crystalline bedrock. 

Bedrock is within 25 ft of the land surface along the southern 

edge of New Post, where it forms a major hydraulic boundary for the glacial aquifer, but is more than 100 ft below land 

surface beneath most of New Post and the area north of the 

community. The topography of the crystalline bedrock in the 

immediate vicinity of New Post is constrained by data from 

three geologic borings drilled for the original study (Juckem 

and Hunt, 2007). However, the crystalline-bedrock elevation is 

only approximately known at distance from these boreholes.
Results of Simulating Potential Replacement Wells 3

The distant hydraulic boundaries for the system are 

directly derived from the regional model of Juckem and Hunt 

(2007). However, the local hydraulic boundaries are important 

for determining well capture zones because capture zones 

in this area depend on the distribution of flow between two 

competing discharge points or “sinks” for the ground-water 

system. The first possible sink is the regionally important 

Chippewa Flowage. The second is the potential replacement 

well. Where simulated pumping reverses the vertical gradient 

(lowers ground-water heads below the Chippewa Flowage to a 

level below the lake stage), surface water from the flowage can 

enter the aquifer. Thus, the conceptual model includes local 

infiltration of precipitation that recharges the ground-water 

system and potential local surface-water leakage from the 

Chippewa Flowage. The recharge and potential surface-water 

leakage is in turn captured by either the Chippewa Flowage or 

the replacement well with simulated pumping. 

Refinement of the Model to Simulate 

Possible Replacement Wells

Linesinks and inhomogeneities of the original regional 

ground-water-flow model of Juckem and Hunt (2007) were 

locally refined to improve simulation of local-scale groundwater/surface-water interaction along the Chippewa Flowage 

near New Post. For the refined model simulations, properties of the regional model remained unchanged, except the 

streambed resistance and width parameters for the Chippewa 

Flowage. Streambed resistance is defined as the thickness 

of sediment between a surface-water body and the aquifer, 

divided by the vertical hydraulic conductivity of the sediment; 

in its mathematically reduced form, streambed resistance is 

expressed in units of days. For example, a model value of 0.5 

days used to simulate streambed sediments (Juckem and Hunt, 

2007) corresponds to a 1-ft sediment thickness and a vertical hydraulic conductivity of 2 ft/d. Reservoirs and flowages, 

which are the result of manmade flooding, are expected to 

have low resistance because they lack much of the fine-grained 

sediment that underlies lakes created by sediment-laden glaciers (Graczyk and others, 2003).

Two streambed resistances were simulated for each of 

three potential replacement wells pumping at 30,000 gal/d, 

for a total of six scenarios. The first approach represented low 

streambed resistance to vertical ground-water flow along the 

Chippewa Flowage. Assumptions for this approach are minimal sediment thickness (0.1 ft) between the Chippewa Flowage and the aquifer, and an estimated horizontal to vertical 

hydraulic conductivity ratio of 3:1 (Kenoyer, 1988). This ratio 

was multiplied by the calibrated horizontal hydraulic conductivity of the regional model (58.2 ft/d; Juckem and Hunt, 2007) 

to compute a vertical hydraulic conductivity of 19.4 ft/d and a 

resistance of 0.005 day along the Chippewa Flowage. This low 

vertical resistance represents an end extreme for which there is 

a high potential for surface-water leakage into the aquifer due 

to pumping. 

The second approach incorporated high streambed 

resistance to vertical ground-water flow by applying the same 

vertical hydraulic conductivity (19.4 ft/d) across 100 ft of 

aquifer material. The computed resistance of 5.2 days approximates the thickness of aquifer material between the Chippewa 

Flowage (1,311.77 ft elevation) and a well with a 20-ft screen 

placed at the bottom of the aquifer (approximately 1,192 ft elevation at borehole BH-2; Juckem and Hunt, 2007). This higher 

vertical resistance represents an end extreme that is more than 

two orders of magnitude larger than the computed resistance 

to vertical flow in a homogeneous and isotropic aquifer due 

to representing a three-dimensional flow system with a twodimensional model (equation 38 of Haitjema, 2005). Thus, 

there is relatively less potential for surface-water leakage into 

the aquifer due to pumping for simulations incorporating this 

higher resistance. 

The refined model was used to simulate contributing 

areas and ground-water/surface-water interactions for three 

replacement wells pumping 30,000 gal/d. Two end extremes 

representing a reasonable range in resistance to vertical 

ground-water flow were simulated for each pumping well 

scenario. In all, a total of six simulations of the refined model 

were done. Each simulation included one of three possible 

replacement wells and one of two values of streambed resistance along the Chippewa Flowage. The contributing area for 

each potential replacement well was delineated by backward 

particle tracking to the water table for 100 hypothetical particles of water placed at the bottom of the well. Surface-water 

leakage into the aquifer from the Chippewa Flowage also was 

quantified for scenarios in which leakage occurred. 

Results of Simulating Potential 

Replacement Wells

Scenario 1 (fig. 1) simulated pumping from a well at 

borehole BH-2 and low resistance (0.005 day) to vertical flow 

along the Chippewa Flowage. The contributing area extended 

from the crystalline bedrock mound at the southern boundary 

of the local aquifer to the Chippewa Flowage at the northern 

boundary. Surface-water leakage from the Chippewa Flowage 

accounted for 39 percent (11,800 gal/d) of the water captured 

by the well. Because of the low resistance along the Chippewa 

Flowage and the two-dimensional formulation of ground-water 

flow in the model, this scenario represents an upper bound to 

the expected amount of surface-water leakage for pumping 

30,000 gal/d from a well near BH-2.

Scenario 2 (fig. 2) simulated pumping from a well at 

borehole BH-2 and high resistance (5 days) associated with 

100 ft of aquifer material below the Chippewa Flowage. 

The contributing area extended from the crystalline bedrock 

mound to the Chippewa Flowage, but also included an area 

north of the flowage. Water captured from the north side of the 
4 Simulation of Contributing Areas and Surface-Water Leakage to Potential Replacement Wells, New Post, Wis.

Chippewa Flowage offset some of the surface-water leakage 

captured by the well in scenario 1. Surface-water leakage from 

the Chippewa Flowage accounted for about 1 percent (340 

gal/d) of the water captured by the well. 

Scenarios 3 and 4 (figs. 3 and 4) simulated pumping from potential replacement well B (lat 45o53'46.40"N., 

long 91o11'7.45"W.), with low and high resistance along the 

Chippewa Flowage, respectively. Both scenarios produced 

a contributing area that extended from the crystalline bedrock mound to within about 100 ft of the Chippewa Flowage 

shoreline, and neither induced surface-water leakage from the 

Chippewa Flowage. 

Scenarios 5 and 6 (figs. 5 and 6) simulated pumping from potential replacement well C (lat 45o53'42.44"N., 

long 91o11'31.13"W.), and low and high resistance along the 

Chippewa Flowage, respectively. The contributing area for 

both scenarios extended from the crystalline bedrock mound 

to within a few hundred feet of a small bay connected to the 

Chippewa Flowage. Similar to scenarios 3 and 4, no surfacewater leakage was simulated for scenarios 5 or 6.

Discussion

Pumping from an aquifer can induce downward vertical 

hydraulic gradients between a nearby surface-water feature 

and the well screen. The magnitude of ground-water/surfacewater interaction depends in part upon the resistance to vertical flow associated with the aquifer material and any intervening confining units, as well as the horizontal distance between 

the well and the surface-water feature. Haitjema (2006) 

demonstrated that resistance to vertical flow near a surfacewater feature is important within a distance equal to twice the 

saturated thickness times the square root of the horizontal to 

vertical hydraulic conductivity ratio of the aquifer. Given the 

assumptions for simulations described in this report (a 3:1 

hydraulic conductivity ratio and 120 ft of saturated aquifer 

thickness), the vertical component of flow can be considered 

important within about 415 ft of the Chippewa Flowage. In 

other words, the two-dimensional model may not accurately 

approximate three-dimensional flow within about 415 ft, 

which can have a minor effect on heads, leakage, and contributing areas within this distance (Haitjema, 2006). Borehole 

BH-2 is approximately 130 ft from the flowage. Potential 

replacement well B is approximately 530 ft from the flowage, 

where as potential replacement well C is approximately 400 ft 

from the flowage. 

As described above, simulations of pumping from a 

potential replacement well at BH-2 are within the distance to 

a surface-water feature for which vertical flow is important. 

Potential replacement wells B and C are near or outside the 

distance for which vertical flow is expected to be important. 

Although limitations associated with the two-dimensional 

model may be present in scenarios 1 and 2, the simulated 

range in resistance values was expected to provide a reasonable range of surface-water leakage from the Chippewa Flowage under steady-state conditions. Moreover, the similarity of 

results for simulations with low and high resistance provides 

additional confidence that pumping 30,000 gal/d from potential replacement wells B and C would induce little, if any, 

surface-water leakage into the aquifer. 

Scenario testing with a three-dimensional model calibrated to vertical water-level data could further decrease 

uncertainty in the results described in this report. Moreover, 

transient simulations incorporating fluctuations in the water 

level of the Chippewa Flowage would provide insight into 

the natural exchange of water between the flowage and the 

aquifer, as well as help constrain estimates of resistance of the 

Chippewa Flowage streambed. Additional transient water-level 

collection in vertically nested monitoring wells in the immediate vicinity of the area of interest would improve the ability 

to estimate values of vertical hydraulic conductivity in the 

aquifer, which is important for simulating contributing areas 

and ground-water/surface-water interaction. 
Results of Simulating Potential Replacement Wells 5

Figure 1. Simulated contributing area for a potential replacement well at borehole BH-2 pumping 30,000 gallons per day, and low 

resistance (0.005 day) to vertical flow along the Chippewa Flowage (scenario 1).

1312.5

1312.0

1312.0

1312.5

Base = 1,192 feet

Sawyer County

Base = 1,230 feet

Hwy CC

Crystalline bedrock mound (no ground-water flow)

0 1,000 2,000 FEET

0 300 600 METERS

Simulated water-table contour 

at 0.5-foot intervals. Datum is NAVD 88.

Analytic element for GFLOW

Road

EXPLANATION

Well with simulated pumping and name

Well without simulated pumping

BH-2

BH-2

Direction of flow

Existing New Post

water-supply wells

Potential replacement well B

Potential replacement well C

Contributing area for a

potential replacement well (BH-2)

pumping 30,000 gallons per day

91 ̊11'37"

45 ̊54'20"

45 ̊54'06"

45 ̊53'40"

91 ̊10'40"

Chippewa Flowage

stage = 1,311.77 feet
6 Simulation of Contributing Areas and Surface-Water Leakage to Potential Replacement Wells, New Post, Wis.

Figure 2. Simulated contributing area for a potential replacement well at borehole BH-2 pumping 30,000 gallons per day, and 

high resistance (5 days) to vertical flow along the Chippewa Flowage (scenario 2).

1312.5

1312.0

1312.0

1312.5

Base = 1,192 feet

Sawyer County

Base = 1,230 feet

Hwy CC

Crystalline bedrock mound (no ground-water flow)

0 1,000 2,000 FEET

0 300 600 METERS

Simulated water-table contour 

at 0.5-foot intervals. Datum is NAVD 88.

Analytic element for GFLOW

Road

EXPLANATION

Well with simulated pumping and name

BH-2

BH-2

Direction of flow

Existing New Post

water-supply wells

Potential replacement well C

Contributing area for a

potential replacement well (BH-2)

pumping 30,000 gallons per day

Well without simulated pumping

91 ̊11'37"

45 ̊54'20"

45 ̊54'06"

45 ̊53'40"

91 ̊10'40"

Chippewa Flowage

Potential replacement well B stage = 1,311.77 feet
Results of Simulating Potential Replacement Wells 7

Figure 3. Simulated contributing area for potential replacement well B, pumping 30,000 gallons per day, with low resistance 

(0.005 day) to vertical flow along the Chippewa Flowage (scenario 3).

1312.5

1312.0

1312.0

Base = 1,192 feet

Sawyer County

Base = 1,230 feet

Hwy CC

Crystalline bedrock mound (no ground-water flow)

0 1,000 2,000 FEET

0 300 600 METERS

Simulated water-table contour 

at 0.5-foot intervals. Datum is NAVD 88.

Analytic element for GFLOW

Road

EXPLANATION

Well with simulated pumping and name B

B

Direction of flow

Potential replacement well C

Well without simulated pumping

91 ̊11'37"

45 ̊54'20"

45 ̊54'06"

45 ̊53'40"

91 ̊10'40"

Chippewa Flowage

stage = 1,311.77 feet

Potential replacement well at BH-2

Existing New Post

water-supply wells

Contributing area for a

potential replacement well (well B)

pumping 30,000 gallons per day
8 Simulation of Contributing Areas and Surface-Water Leakage to Potential Replacement Wells, New Post, Wis.

Figure 4. Simulated contributing area for potential replacement well B, pumping 30,000 gallons per day, with high resistance (5 

days) to vertical flow along the Chippewa Flowage (scenario 4).

1312.5

1312.0

Base = 1,192 feet

Sawyer County

Base = 1,230 feet

Hwy CC

Crystalline bedrock mound (no ground-water flow)

0 1,000 2,000 FEET

0 300 600 METERS

Simulated water-table contour 

at 0.5-foot intervals. Datum is NAVD 88.

Analytic element for GFLOW

Road

EXPLANATION

Well with simulated pumping and name B

B

Direction of flow

Potential replacement well C

Well without simulated pumping

91 ̊11'37"

45 ̊54'20"

45 ̊54'06"

45 ̊53'40"

91 ̊10'40"

Chippewa Flowage

stage = 1,311.77 feet

Potential replacement well at BH-2

Existing New Post

water-supply wells

Contributing area for a

potential replacement well (well B)

pumping 30,000 gallons per day
Results of Simulating Potential Replacement Wells 9

Figure 5. Simulated contributing area for potential replacement well C, pumping 30,000 gallons per day, with low resistance 

(0.005 day) to vertical flow along the Chippewa Flowage (scenario 5).

1312.5

1312.0

Base = 1,192 feet

Sawyer County

Base = 1,230 feet

Hwy CC

Crystalline bedrock mound (no ground-water flow)

0 1,000 2,000 FEET

0 300 600 METERS

Simulated water-table contour 

at 0.5-foot intervals. Datum is NAVD 88.

Analytic element for GFLOW

Road

EXPLANATION

Well with simulated pumping and name C

C

Direction of flow

Potential replacement well B

Well without simulated pumping

91 ̊11'37"

45 ̊54'20"

45 ̊54'06"

45 ̊53'40"

91 ̊10'40"

Chippewa Flowage

stage = 1,311.77 feet

Potential replacement well at BH-2

Existing New Post

water-supply wells

Contributing area for a

potential replacement well (well C)

pumping 30,000 gallons per day
10 Simulation of Contributing Areas and Surface-Water Leakage to Potential Replacement Wells, New Post, Wis.

Figure 6. Simulated contributing area for potential replacement well C, pumping 30,000 gallons per day, with high resistance (5 

days) to vertical flow along the Chippewa Flowage (scenario 6).

1312.5

1312.0

91 ̊11'37"

45 ̊54'20"

45 ̊54'06"

45 ̊53'40"

91 ̊10'40"

Base = 1,192 feet

Sawyer County

Base = 1,230 feet

Hwy CC

Crystalline bedrock mound (no ground-water flow)

0 1,000 2,000 FEET

0 300 600 METERS

Simulated water-table contour 

at 0.5-foot intervals. Datum is NAVD 88.

Analytic element for GFLOW

Road

EXPLANATION

Well with simulated pumping and name C

C

Direction of flow

Potential replacement well B

Well without simulated pumping

Chippewa Flowage

stage = 1,311.77 feet

Potential replacement well at BH-2

Existing New Post

water-supply wells

Contributing area for a

potential replacement well (well C)

pumping 30,000 gallons per day
References Cited 11

Summary

Six scenarios were simulated to evaluate contributing 

areas and surface-water leakage associated with pumping 

from three potential replacement well locations. For each well 

location, two cases were evaluated: one in which resistance 

to vertical flow was negligible and one in which resistance to 

vertical flow was substantial. Surface-water leakage ranged 

from 39 percent to less than 1 percent of total well pumping 

for a well at borehole BH-2 (scenarios 1 and 2), a location 

that is within 130 ft of the Chippewa Flowage and sufficiently 

close for vertical flow to be important. The simulated contributing area extended from the Chippewa Flowage to a crystalline bedrock mound south of the community of New Post for 

both scenarios, but it also extended north of the flowage for 

the high-streambed-resistance scenario in which surface-water 

leakage represented less than 1 percent of well capture (scenario 2). For the remaining two potential well locations (scenarios 3 through 6), no surface-water leakage was simulated 

because of the increased distance from the Chippewa Flowage. 

In all scenarios, the simulated range in resistance to vertical 

flow was expected to provide reasonable bounds for surfacewater leakage - a range that compensates for the limitations 

associated with approximating three-dimensional flow near a 

surface-water feature with a two-dimensional model (primarily 

important in scenarios 1 and 2). 

References Cited

Graczyk, D.J., Hunt, R.J., Greb, S.R., Buchwald, C.A., and 

Krohelski, J.T., 2003, Hydrology, nutrient concentrations, 

and nutrient yields in nearshore areas of four lakes in northern Wisconsin, 1999–2001: U.S. Geological Survey WaterResources Investigations Report 03–4144, 64 p.

Haitjema, H.M., 1995, Analytic element modeling of groundwater flow: San Diego, Calif., Academic Press, 394 p.

Haitjema, H.M., 2005, Dealing with resistance to flow into 

surface waters: Unpublished document, 9 p., accessed 

August 31, 2007, at http://www.haitjema.com/documents/De

alingwithresistancetoflowintosurfacewaters.pdf

Haitjema, Henk, 2006. The role of hand calculations in ground 

water flow modeling: Ground Water, v. 44, no. 6, 

p. 786–791. 

Hunt, R.J., 2006, Ground water modeling applications using 

the analytic element method: Ground Water, v. 44, no. 1, 

p. 5–14.

Hunt, R.J., Anderson, M.P., and Kelson, V.A., 1998, Improving a complex finite-difference ground water flow model 

through the use of an analytic element screening model: 

Ground Water, v. 36, no. 6, p. 1011–1017.

Hunt, R.J., Haitjema, H.M., Krohelski, J.T., and Feinstein, 

D.T., 2003, Simulating ground water-lake interactions—

Approaches and insights: Ground Water, v. 41, no. 2, 

p. 227–237.

Hunt, R.J., and Krohelski, J.T., 1996, The application of an 

analytic element model to investigate groundwater-lake 

interactions at Pretty Lake, Wisconsin: Journal of Lake and 

Reservoir Management, v. 12, no. 4, p. 487–495.

Juckem, P.F., and Hunt, R.J., 2007, Simulation of the shallow ground-water-flow system near Grindstone Creek and 

the Community of New Post, Sawyer County, Wisconsin. 

U.S. Geological Survey Scientific Investigations Report 

2007–5014, 29 p.

Kenoyer, G.J., 1988, Tracer test analysis of anisotropy in 

hydraulic conductivity of granular aquifers: Ground Water 

Monitoring Review, v. 8, no. 3, p. 67–70.

Tyrolt, D.D., 2006, New Post soil boring sieve analysis report: 

Unpublished document on file at the Lac Courte Oreilles 

Conservation Department, 21 p.
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Juckem and Hunt—Simulation of Contributing Areas and Surface-Water Leakage to Potential Replacement Wells, New Post, Wis.—Open-File Report 2008–1133

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