Ground-Water Resources of the Uppermost Confined Aquifers, Southern Wadena County and Parts of Ottertail, Todd, and Cass Counties, Central Minnesota, 1997-2000

By R.J. Lindgren

Water-Resources Investigations Report 02–4023

Prepared in cooperation with the Minnesota Department of Natural Resources and the Wadena Soil and Water Conservation District U.S. DEPARTMENT OF THE INTERIOR Gale A. Norton, Secretary

U.S. GEOLOGICAL SURVEY Charles G. Groat, Director

Use of brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey.

Mound View, Minnesota, 2002

For additional information write to: U.S. Geological Survey District Chief 2280 Woodale Drive Mounds View, MN 55112

Copies of this report can be purchased from:

U.S. Geological Survey Branch of Information Services Box 25286, MS 517 Federal Center Denver, CO 80225

For more information on the USGS in Minnesota, you may connect to the Minnesota District home page at http://mn.water.usgs.gov For more information on all USGS reports and products (including maps, images, and computerized data), call 1-888-ASK-USGS

Water-Resources Investigations Report 02–4023 CONTENTS

Abstract...... 1 Introduction ...... 2 Description of study area...... 2 Methods of investigation...... 4 Log data, test drilling, and well installation...... 4 Water levels and stream discharge ...... 4 Theoretical maximum well yields...... 4 Modeling of ground-water flow...... 8 Acknowledgments...... 8 Hydrogeology...... 8 Hydrogeologic units ...... 9 Hydraulic properties...... 14 Hydrology...... 14 Ground-water withdrawals...... 14 Vertical hydraulic connection between aquifers...... 16 Stream-aquifer leakage...... 19 Theoretical maximum well yields in uppermost confined aquifers ...... 19 Simulation of ground-water flow ...... 19 Numerical model description ...... 19 Numerical model calibration...... 29 Steady-state simulation ...... 30 Transient simulation...... 35 Effects of ground-water withdrawals ...... 37 Historical withdrawals...... 40 Anticipated increases in withdrawals...... 41 Anticipated increases in withdrawals during a drought ...... 41 Greater than anticipated increases in withdrawals ...... 46 Greater than anticipated increases in withdrawals during a drought ...... 46 Model limitations and accuracy of results...... 46 Summary...... 47 References ...... 48 Glossary...... 50 ILLUSTRATIONS

Figures 1-8. Maps showing: 1. Location of study area, observation wells, and extent of surficial aquifer, southern Wadena County and parts of surrounding counties, Minnesota...... 3 2. Location of stream-stage and stream-discharge measurement sites, and extent of surficial aquifer, southern Wadena County and parts of surrounding counties, Minnesota...... 5 3. Location of high-capacity water-supply wells and dug pits, and extent of surficial aquifer, southern Wadena County and parts of surrounding counties, Minnesota ...... 10 4. Thickness of composite zone and uppermost confined aquifers, southern Wadena County and parts of surrounding counties, Minnesota ...... 11 5. Depth to top of uppermost confined aquifers and extent of surficial aquifer, southern Wadena County and parts of surrounding counties, Minnesota ...... 12 6. Thickness of uppermost confining units and extent of surficial aquifer, southern Wadena County and parts of surrounding counties, Minnesota ...... 13

iii ILLUSTRATIONS--CONTINUED

7. Altitude of potentiometric surface of surficial aquifer, December 1998, and extent of surficial aquifer, southern Wadena County and parts of surrounding counties, Minnesota ...... 17 8. Altitude of potentiometric surface of uppermost confined aquifers, December 1998, southern Wadena County and parts of surrounding counties, Minnesota...... 17 Figure 9. Hydrographs showing measured and simulated hydraulic heads for selected observation wells completed in surficial and uppermost confined aquifers, transient simulation 1998–99, southern Wadena County and parts of surrounding counties, Minnesota...... 21 Figures 10-16b. Maps showing: 10. Theoretical maximum yield of wells completed in uppermost confined aquifers, southern Wadena County and parts of surrounding counties, Minnesota...... 23 11. Grid for finite-difference ground-water-flow model and model cells with simulated ground-water withdrawals, southern Wadena County and parts of surrounding counties, Minnesota...... 24 12a. Simulated boundary conditions and horizontal hydraulic conductivity zones for ground-water-flow model layer 1, southern Wadena County and parts of surrounding counties, Minnesota...... 26 12b. Simulated boundary conditions and horizontal and vertical hydraulic conductivity zones for ground-water-flow model layer 2, southern Wadena County and parts of surrounding counties, Minnesota...... 27 12c. Simulated boundary conditions and horizontal hydraulic conductivity zones for ground-water-flow model layer 3, southern Wadena County and parts of surrounding counties, Minnesota...... 28 13. Simulated areal recharge and leakage zones for ground-water-flow model, southern Wadena County and parts of surrounding counties, Minnesota ...... 31 14a. Measured water-level altitude in the surficial aquifer, December 1998, and simulated altitude of potentiometric surface for model layer 1, steady-state conditions, and extent of surficial aquifer, southern Wadena County and parts of surrounding counties, Minnesota ...... 32 14b. Measured water-level altitude in the uppermost confined aquifers, December 1988, and simulated altitude of potentiometric surface for model layer 3, steady-state conditions, southern Wadena County and parts of surrounding counties, Minnesota ...... 33 15. Storage coefficient zones for ground-water-flow model layer 3, southern Wadena County and parts of surrounding counties, Minnesota ...... 38 16a. Extent of surficial aquifer and simulated drawdowns for model layer 1, representing the surficial aquifer, due to historical ground-water withdrawals, steady-state simulation, southern Wadena County and parts of surrounding counties, Minnesota ...... 42 16b. Simulated drawdowns for model layer 3, representing the uppermost confined aquifers, due to historical ground-water withdrawals, steady-state simulation, southern Wadena County and parts of surrounding counties, Minnesota...... 43 17a. Extent of surficial aquifer and simulated drawdowns for model layer 1, representing the surficial aquifer, due to anticipated increased ground-water withdrawals and drought conditions, steady-state simulation, southern Wadena County and parts of surrounding counties, Minnesota ...... 44 17b. Simulated drawdowns for model layer 3, representing the uppermost confined aquifers due to anticipated increased ground-water withdrawals and drought conditions, steady-state simulation, southern Wadena County and parts of surrounding counties, Minnesota ...... 45 TABLES

1. Stream discharge and estimated stream-aquifer leakage under low-flow conditions during 1998–99, and model computed stream-aquifer leakage for the steady-state simulation, southern Wadena County and parts of surrounding counties, Minnesota...... 6 2. Reported values of hydraulic properties and fluxes, southern Wadena County and parts of surrounding counties, Minnesota .....15 3. Ground-water withdrawals during 1997–98 in southern Wadena County and parts of surrounding counties, Minnesota...... 22 4. Initial and final calibration values of hydraulic properties and fluxes simulated in numerical ground-water-flow model, southern Wadena County and parts of surrounding counties, Minnesota ...... 29 5. Simulated water budget for the steady-state model, southern Wadena County and parts of surrounding counties, Minnesota .....34

iv TABLES--CONTINUED

6. Initial and final calibration values of areal recharge, leakage, and ground-water evapotranspiration for transient simulation, southern Wadena County and parts of surrounding counties, Minnesota...... 36 7. Simulated water budget, by stress period, for 1999 for transient simulation, southern Wadena County and parts of surrounding counties, Minnesota ...... 39 8. Summary of steady-state results of hypothetical model Simulations 1-5, southern Wadena County and parts of surrounding counties, Minnesota ...... 40 CONVERSION FACTORS AND VERTICAL DATUM

Multiply by to obtain Inch (in.) 2.54 centimeter Inch per year (in./yr) 2.54 centimeter per year Foot (ft) 0.3048 meter Foot per day (ft/d) 0.3048 meter per day Foot per mile (ft/mi) .1894 meter per kilometer Square mile (mi2) 2.590 square kilometer Foot squared per day (ft2/d) 0.0929 meter squared per day Cubic foot per second (ft3/s) 0.02832 cubic meter per second Gallon per minute (gal/min) 6.309 x 10-5 cubic meter per second

Sea level: In this report, sea level refers to the National Geodetic Vertical Datum of 1929—a geodetic datum derived from a general adjustment of the first-order levels nets of both the United States and Canada, formerly called Sea Level Datum of 1929.

v vi Ground-Water Resources of the Uppermost Confined Aquifers, Southern Wadena County and Parts of Ottertail, Todd, and Cass Counties, Central Minnesota, 1997–2000

By R.J. Lindgren

ABSTRACT (54.5 percent) and ground-water evapotranspiration (41.4 percent). The simulated transient water budget for 1999 Water managers are concerned about the increase of indicated that the principal sources of water to the aquifers ground-water withdrawals from high-capacity wells com- were areal recharge to the surficial aquifer and release from pleted in the uppermost confined aquifers in southern Wadena County. The hydrogeologic units of primary inter- storage. The principal discharges were stream-aquifer leak- est in the study area are the surficial aquifer, the uppermost age, addition to storage, and ground-water evapotranspira- confining units, and the uppermost confined aquifers. The tion. surficial aquifer underlies all but portions of the eastern, Results of the steady-state simulation with anticipated western, and south-central parts of the study area, and is as increases in ground-water withdrawals indicated maximum much as 70 ft thick. The thickness of the uppermost con- drawdowns of 0.3 ft in the surficial aquifer and 0.9 ft in the fined aquifers ranges from 0 to 72 ft. The thickness of the aquifers is greatest in the south-central and west-central uppermost confined aquifers due to the anticipated parts of the study area, where thicknesses exceed 50 ft. increases in ground-water withdrawals. Model results indi- Depth to the top of the uppermost confined aquifers ranges cate that the anticipated increases in withdrawals during a from 23 to 132 ft. The thickness of the uppermost confining drought may lower water levels 2 to 4 ft regionally in much units ranges from 4 to 132 ft. of both the surficial and uppermost confined aquifers. The regional direction of flow in the uppermost con- Water-level declines in the surficial aquifer of about 6 ft fined aquifers is to the east, southeast, and southwest may occur in Wadena and in the central part of the aquifer toward the Crow Wing River in the eastern part of the study south of the Leaf River. Results of the transient simulation area and toward the Leaf River in the western part. Sources indicate that the anticipated increases in withdrawals dur- of water to the uppermost confined aquifers are leakage of ing a drought would increase seasonal declines in the surfi- water through overlying till and clay and ground-water cial and uppermost confined aquifers less than 1 and 2 ft, flow from adjoining aquifers outside the study area. Dis- respectively. charge from the uppermost confined aquifers is by withdrawal from wells and to the surficial aquifer in river Model results indicate that greater than anticipated valleys. The theoretical maximum well yields for the increases in withdrawals during periods of normal precipi- uppermost confined aquifers range from less that 175 tation will have minimal effects on ground-water levels and gal/min to greater than 2,000 gal/min and are greatest in streamflow in the area. In the uppermost confined aquifers, areas of greatest aquifer thickness and transmissivity. for example, water levels may decline an average of 0.13 ft The water budget for the calibrated steady-state simu- regionally, with maximum declines of 0.8 to 2.1 ft near lation indicated that areal recharge to the surficial aquifer is Wadena and Verndale. Greater than anticipated increases in 86.9 percent of the water to the aquifers, with leakage to the withdrawals would cause decreases in ground-water dis- uppermost confined aquifers contributing 6.9 percent. The charge to streams of about 1.4 percent (2.5 ft3/s) of 1998-99 largest discharges from the aquifers are leakage to streams steady-state conditions.

1 INTRODUCTION tion between the surficial and upper- Principal crops include corn and hay. most confined aquifers. Crops most commonly irrigated are Southern Wadena County is an To address these concerns, and to corn, potatoes, and dry edible beans. agricultural area that is part of a large evaluate the ground-water resources Glacial deposits ranging in thick- surficial glacial outwash plain in cen- in the uppermost confined aquifers in ness from 100 to 300 ft cover the tral Minnesota. Without irrigation southern Wadena County, an investi- entire study area. Surficial outwash crops are susceptible to failure during gation was conducted during 1997– consisting of sand and gravel under- dry years in the sandy, well-drained 2000 by the U.S. Geological Survey lies most of southern Wadena County soils. Increased demand for ground (USGS), in cooperation with the Min- (area indicated as surficial aquifer in water in this region has resulted from nesota Department of Natural fig. 1) and is generally of sufficient installation of irrigation systems com- Resources and the Wadena Soil and thickness and permeability to permit pleted in the surficial aquifer (within Water Conservation District. The yields of large (100 to 1,000 gal/min) the surficial glacial outwash) during objectives of this investigation were quantities of water to wells. In the the 1960’s and early 1970’s. Because to: (1) determine the areal extent, moraine and till plain areas of the of the increased demand for ground- thickness, and hydraulic properties of northwestern and southern parts of the water resources beginning in the mid the uppermost confined aquifers in study area, wells are usually com- 1970’s, the source of water for irriga- southern Wadena County, (2) evaluate pleted in buried sand and gravel layers tion shifted from the surficial aquifer the vertical hydraulic connection and at greater depths than those in to the deeper, uppermost confined between the surficial aquifer and the areas of surficial outwash. aquifers. Currently, all new irrigation uppermost confined aquifers, (3) esti- The study area is drained by the wells in southern Wadena County are mate the effects of anticipated Crow Wing River and its tributaries. completed in the uppermost confined increases in ground-water withdraw- Flow in the main stem of the Crow aquifers. als on water levels, and (4) estimate Wing River is stable because of the the long-term yields of wells com- Water managers of the Minnesota regulating effect of lakes and wet- pleted in the uppermost confined Department of Natural Resources lands at medium and high flows, and aquifers. (MDNR) and theWadena County Soil the sustaining effect of ground-water and Water Conservation District are This report presents the results of discharge (base flow) from outwash the investigation. It describes data concerned about the increase of areas during low-flow periods. Mini- collection during 1997–99; sources ground-water withdrawals from high- mum discharges for the Crow Wing and types of other data used; and con- capacity wells completed in the River normally occur in January and struction, calibration, and application uppermost confined aquifers in south- February when the flow is sustained of a numerical ground-water-flow ern Wadena County. Their concerns almost entirely by ground water. model. The primary area of interest include uncertainty about the long- Instantaneous annual maximum flow and data-collection activities was term yields of wells completed in the may occur any time from March southern Wadena County. Parts of uppermost confined aquifers, the through October, but most periods of Ottertail, Todd, and Cass Counties effects of pumping on water levels in sustained high flow result from snow- were included in the study area to the aquifers, and possible interfer- melt in April. The major tributaries of minimize the effects of boundary con- ence between nearby wells. Hydro- the Crow Wing River in the study area ditions in the ground-water-flow geologic information, including the are the Leaf, Wing, Partridge, and Red model. areal extent of the uppermost confined Eye Rivers. Approximate average aquifers, recharge and discharge areas Description of Study Area flows measured in the study area for and rates, hydrologic boundaries, and The study area covers approxi- the Leaf, Wing, Partridge, and Red the hydraulic characteristics of the 2 Eye Rivers for 1931–64 were 70, 25, mately 720 mi in southern Wadena 3 aquifers, is not well known. Although County and parts of Ottertail, Todd, 6, and 35 ft /s, respectively (Lind- numerous wells and test holes have and Cass Counties in central Minne- holm and others, 1972). been completed in the uppermost con- sota (fig. 1). Flat to gently undulating Mean annual precipitation during fined aquifers, little is known about topography characterizes much of the 1961–90 (normal precipitation) was the continuity or the hydraulic area, with locally greater relief near 26.24 in. at Wadena (U.S. Department responses of the aquifer to ground- major streams. Undeveloped lands of Commerce, 1999). Precipitation water withdrawals. Additional water- include wetlands, scattered through- during the growing season, April level data and aquifer tests are needed out the area, and forested areas in the through September, generally com- to understand the hydraulic connec- northeastern part of the study area. prises 75 to 80 percent of the annual

2 95°15' 95°07'30" 95° 94°52'30" 94°45'

46°37'30" 6 s Ck. 1 6 Sebeka 1 6 1 6 1 6 1 Red Beaver Creek Strike Lake T s Granning 136 Lake Oylen N Eye 4 (2) Farnham

Creek

Crow s Hay Creek 31 36 31 36 31 36 31 36 31 36 Creek Martin Creek Blue 1 6 16 (2) 6 1 6 1 6 12N 11 (2) Sand 1 6 1 River Lake Tower s Sugar Creek Creek R. Wells 12S Mud s s Lake Little Farnham T 46°30' OTTER TAIL WADENA 3 (2) COUNTY COUNTY Lake CASS 135 6 7 (2) N N. River 13 (2) COUNTY Bluff Leaf 15 (2) 8 (2) River Pulver Creek Creek Bluffton Leaf Lake

Creek 31 36 31 36 31 36 31 36 31 s Iron 36 Ck. Radabaugh 6 5 (2) 1 6 s 1 1 6 1 1 Wadena 6 Lake6 s s River Ck. Rice Simon South

Lovejoy Lake Creek Creek Lake Lake Wing T Whiskey 2 (3) s Farber Cat 134 14 (3) Lake Lake Verndale N Union 10 (2) s Johnson Wing River Lake 9 (2) s Dog Lake

31 B. Swenson 36 31 31 Aldrich 46°22'30" 36 36 31 Creek 36 31 36 Bluff 1 (2) s

6 6 Benz 1 1 s 1 6 1 6 Staples 1 6 Dower Lakes Moran Lake River s

Oak Stones R. Tucker Creek Edwards Lake Hayden Lake Hewitt Lake T TODD Hayden Lake s Jacobson 133 Munn Lake River

COUNTY Lawrence N South s Bear Lake s Lake Prairie Jasmer F. Schmidt Partridge

s Lake

Long Partridge

Creek S. 31 36 31 36 31 36 31 36 31 36

R 36 W R 35 W R 34 W R 33 W R 32 W Base from U.S. Geological survey digital data 1:100,000, 1972 US Albers Equal Area Projection standard parallels 29°30' and 45°30', central meridian -95° 0 5 10 MILES

0 5 10 KILOMETERS

96° 94° EXPLANATION 92° 90° Extent of surficial aquifer 48° Area where surficial aquifer is absent Study Lake Superior 9 (2) Area USGS observation well. Number is U.S.

Geological Survey well site number.

M i

s s Number in parentheses indicates 46° i s s i p p i nested wells at a site

River Minnesota R. Wells Domestic irrigation or public-supply

River well used as an observation well. Name refers to hydrograph shown 44° in figure 9 s 0 50 100 MILES MDNR observation well completed in 0 50 100 KILOMETERS surficial aquifer Location Map

Figure 1. Location of study area, observation wells, andextent of surficial aquifer, southern Wadena County and parts of surrounding counties, Minnesota.

3 total. Moisture is adequate for opti- lic properties of the glacial-deposit were installed in 9 of the observation mum plant growth in spring and early aquifers in southern Wadena County wells and water levels were recorded summer during a normal year, but a and of surrounding counties were hourly. Stream stage was measured typical moisture deficiency during compiled from water-well logs, geo- monthly during open water conditions August and September results in less logic maps, State and Federal data at 11 sites on the Crow Wing, Leaf, than optimum growth. Rural and bases, water-use records, published Wing, Partridge and Red Eye Rivers municipal water shortages were com- reports, and consultant reports. Addi- in close proximity to observation mon during droughts in the 1930’s, tional test drilling, well installation, wells (fig. 2). Stream stage was mea- 1970’s, and 1980’s. Annual precipita- and measurements of water levels and sured at varying time intervals at an tion during 1998 and 1999 was above stream discharge were done for this additional 47 sites on the major rivers normal (34.78 and 31.41 in., respec- investigation. Observation-well and and selected tributaries (fig. 2). tively). In 1998, precipitation during test-hole logs, water-level measure- The altitudes of all measurement May and June was 5.1 in. above nor- ments, and stream-discharge measure- points were determined by surveying mal (1961–90 mean), during August ments done for this investigation are from points of known land-surface and September was 2.6 in. below nor- on file at the USGS, Mounds View, altitudes (Greg Payne, U.S. Geologi- mal, and during October was 6.3 in. Minnesota. cal Survey, written commun., 1999). above normal. In 1999, precipitation Log Data, Test Drilling, and Well Altitudes of measuring points were during May and June was 3.4 in. Installation measured with a precision of 0.10 ft. above normal, during July through Synoptic sets of low-flow dis- Water-well and test-hole logs September was 5.3 in. above normal, charge measurements were made to and during October was 1.8 in. below were obtained from the Minnesota determine gaining and losing reaches normal. Geological Survey’s County Well of the major rivers and selected tribu- Index and from the USGS Ground- Mean annual potential evapo- taries and to quantify streamflow Water Site Inventory data base for transpiration in the study area calcu- gains and losses. Low-flow discharge lated by the Thornthwaite method is Wadena, Ottertail, Todd, and Cass measurements were made during Counties. Test drilling was conducted 22 to 23 in./yr (Baker and others, August 1998, and during November to: (1) install observation wells com- 1979). Evaporation from pans can 1999 (fig. 2; table 1). The uncertainty also be used to estimate evapotranspi- pleted in the uppermost confined of individual streamflow measure- aquifers, (2) establish nests of obser- ration, since the same physical pro- ments was 5–8 percent (table 1). vation wells completed in the surficial cess is involved (Baker and others, Theoretical Maximum Well Yields 1979). Pan evaporation usually shows and uppermost confined aquifers, and an evaporation amount that is even (3) install observation wells near Theoretical maximum well yields greater than the potential evapotrans- streams to determine relations in the uppermost confined aquifers piration obtained by the Thornthwaite between stream stages and aquifer were estimated using a chart devel- or other calculation methods. Pan hydraulic heads. Thirty-four test holes oped by Meyer (1963) that relates evaporation has been measured at Sta- were drilled for this investigation at well diameter, specific capacity, val- ples, Minnesota during April-Septem- 17 sites, and observation wells were ues of transmissivity, and storage ber since 1977. Average annual pan installed in 33 of the test holes (fig. coefficient. The chart shows that for 1). Nested observation wells were transmissivities between approxi- evaporation at Staples during 1977– 2 99 was 39.43 in. (Mel Wiens, Central completed in the surficial and upper- mately 270 and 13,000 ft /d, the ratio Minnesota Agricultural Center, Sta- most confined aquifers at 14 of the of transmissivity to specific capacity ples, Minnesota, written commun., sites. is about 320 to 1. For confined aquifers with transmissivities of 13,000 2000). Annual pan evaporation during Water Levels and Stream Discharge 2 1998 and 1999 was 43.46 and 39.43 ft /d or less, the specific capacity is in., respectively. In 1998, pan evapo- Water levels were measured approximated by dividing the trans- ration during August through Septem- monthly in the 33 observation wells, missivity by 320. The theoretical ber was 2.5 in. above normal (1977– 22 MDNR observation wells com- maximum well yield at a site was esti- 99 average), whereas in 1999 it was pleted in the surficial aquifer, and 71 mated by multiplying the specific 1.2 in. below normal. domestic, irrigation, and public-sup- capacity by the available drawdown. ply wells (fig. 1). All of the 71 domes- The available drawdown, as defined Methods of Investigation tic, irrigation, and public-supply wells for this report, is the difference Previously collected data on the were completed in the uppermost con- between the altitudes of the static hydrogeology, water use, and hydrau- fined aquifers. Pressure transducers (nonpumping) water level in a well

4 Nimrod D 95°15' 95°07'30" 95° SW1 94°52'30" Little Swamp Ck. 94°45' 46°37'30" 6 D SW15 Ck. 1 6 Sebeka 1 6 1 6 1 6 1 Red Beaver Creek Strike Lake T Granning 136 Lake Oylen N Eye Farnham SW2 D Creek

Crow Hay Creek 31 36 31 36 31 36 31 36 31 36 Creek Creek D Martin Blue 6 1 6 1 6 SW161 6 Sand 1 6 1 River Lake Tower Sugar Creek Mud Creek Lake SW3 D Little Farnham T 46°30' OTTER TAIL WADENA COUNTY SW8 D COUNTY Lake CASS 135 SW7 D D N N. River SW17 COUNTY Bluff Leaf D River Pulver Creek Bluffton Leaf SW9 Creek D D D Lake D Creek 31 36 31 36 31 SW12 36 31 36 31 Iron 36 Ck. D D SW6 Radabaugh 6 1 6 6 SW10 1 1 1 6 1 Lake D Wadena 6

River Ck. Rice Simon South

Lovejoy Lake Creek Creek Lake Lake Wing SW4 T

Whiskey D D Farber Cat 134 SW14 Lake D Lake N Union Verndale Johnson Wing River Lake SW11 Dog D Lake

31 36 31 31 Aldrich 46°22'30" 36 36 31 Creek 36 31 36 Bluff D D SW5 6 6 Benz 1 1 1 6 1 6 Staples 1 6 D Dower Lake Moran River SW13 Lake

Oak Stones R. Tucker Creek Edwards Lake Hayden Lake Hewitt Lake TODD Jacobson Hayden Lake Munn Lake River COUNTY Lawrence South Bear Lake T Lake Prairie Jasmer 133 Partridge Lake N

Long Partridge

Creek S. 31 36 31 36 31 36 31 36 31 36

R 36 W R 35 W R 34 W R 33 W R 32 W Base from U.S. Geological survey digital data 1:100,000, 1972 US Albers Equal Area Projection 0 5 10 MILES standard parallels 29°30' and 45°30', central meridian -95° 0 5 10 KILOMETERS

EXPLANATION

Extent of surficial aquifer

Area where surficial aquifer is absent

Stream-stage periodic measurement site

Stream-discharge measurement site D SW7 Stream-stage periodic and stream-discharge measurement site Number refers to surface-water site identifier, shown in table 1

Figure 2. Location of stream-stage and stream-discharge measurement sites, andextent of surficial aquifer, southern Wadena County and parts of surrounding counties, Minnesota.

5 (-) in (-) +9.0 +9.9 aquifer leakage Stream- +13.1 +12.2 +12.3 +12.5 +17.2 simulation streamflow Steady-state Steady-state gain(+) or loss steady-state simulation, 14.7 aquifer -38 -19.3 -39.9 leakage leakage Stream- +24.7 +15.6 loss (-) in loss gain(+) or streamflow +148.3 0.8 6.9 0.7 9.9 9.8 17.1 14.2 14.2 13.6 14.3 59.4 303 Tributary Tributary discharge discharge November 1999 November eam-aquifer leakage for the 74.0 Stream 474 630 592 907 882 122 161 236 discharge discharge

Measured -- -6.0 -6.1 +9.0 aquifer leakage leakage Stream- +27.6 +35.6 +18.1 loss (-) in gain(+) or streamflow 1.0 1.0 4.0 1.3 2.1 5.2 ------12.1 30.9 194 Tributary Tributary discharge discharge August 1998 August of surrounding counties, Minnesota less otherwise noted; --, no measurement] -- 65.2 Leaf River Leaf Stream 335 346 340 544 575 106 155 discharge discharge Crow Wing River Stream reach reach Stream SW1-SW2 SW2-SW3 SW3-SW4 SW4-SW5 SW6-SW7 SW7-SW8 SW8-SW9 under low-flow conditions during 1998-99, and model computed str [All values in cubic feet per second un southern Wadena County andparts southern Wadena 5 8 8 8 5 5 5 5 5 5 5 5 5 5 5 8 5 5 (percent) Discharge Discharge uncertainty uncertainty measurement Tributary site Tributary Little Swamp Creek Swamp Little Beaver Creek Farnham Creek Leaf River (SW10) (SW14) Partridge River Hayden Creek Creek South Creek Bluff South Creek Bluff North Oak Creek Creek Union (SW12) River Wing Site identifier identifier Site (shown in fig. 2) SW1 SW2 SW3 SW4 SW5 SW6 SW7 SW8 SW9 Table 1. Stream discharge and estimated stream-aquifer leakage discharge 1. Stream Table 6 (-) in (-) +6.7 +9.0 +4.9 aquifer leakage Stream- +13.1 +12.5 simulation streamflow Steady-state Steady-state gain(+) or loss steady-state simulation, +8.7 +8.8 +6.3 +9.8 aquifer leakage leakage Stream- +13.9 loss (-) in loss gain(+) or streamflow 0.0 58.3 Tributary Tributary discharge discharge 7.9 eam-aquifer leakage for the 50.6 59.4 14.2 34.6 48.5 58.3 Stream 303 discharge discharge Measured -2.6 +4.6 aquifer leakage leakage Stream- +11.7 +14.7 +10.9 loss (-) in gain(+) or streamflow 0.0 34.4 Tributary Tributary discharge discharge August 1998August 1999 November less otherwise noted; --, no measurement] surrounding counties, Minnesota (Continued) 0.4 16.2 30.9 12.1 26.1 37.0 34.4 Stream Wing River 194 discharge discharge Red Eye River Partridge River Partridge Stream reach reach Stream SW9-SW10 SW11-SW12 SW13-SW14 SW15-SW16 SW16-SW17 under low-flow conditions during 1998-99, and model computed str [All values in cubic feet per second un 5 8 5 5 5 5 5 5 (percent) Discharge Discharge uncertainty uncertainty measurement southern Wadena County and parts of southern Wadena Tributary site Tributary Red Eye River (SW17) Eye River Red Hay Creek Site identifier identifier Site (shown in fig. 2) SW10 SW11 SW12 SW13 SW14 SW15 SW16 SW17 Table 1. Stream discharge and estimated stream-aquifer leakage discharge 1. Stream Table 7 and the bottom of the uppermost con- Acknowledgments drumlins and thinnest where it over- fined aquifer penetrated. The avail- lies buried drumlins. The outwash is able drawdown was estimated to be The author is grateful to landown- composed of glaciofluvial sand and the sum of aquifer thickness and the ers who allowed the installation of gravel. All till in the Wadena area is artesian head (the hydraulic head observation wells on their property sandy and calcareous. It is yellowish above the altitude of the top of the and who permitted water-level mea- brown when oxidized and commonly uppermost confined aquifer). An surements. The author is also grateful dark greenish gray when unoxidized. average value of 35 ft was used for to Don Sertich and Jeremy Maul of Unoxidized Wadena-lobe till is fre- the artesian head, based on measured the Wadena Soil and Water Conserva- quently found at depth in drill holes, water levels and aquifer top altitudes tion District for obtaining monthly and it forms the confining unit from well logs. The estimates of theo- water-level measurements in domestic beneath outwash deposits throughout retical maximum well yield included and irrigation wells. Thanks also are the study area. The top several feet of in this report were based on the fol- given to employees of the U.S. Geo- Wadena-lobe till are very sandy, with lowing assumptions: (1) the aquifer is logical Survey for their assistance few exceptions. Sand and gravel homogeneous, isotropic, and infinite with this investigation, particularly lenses ranging from less than five to in areal extent; (2) the well is Michael Menheer, Christopher tens of feet thick occur at various screened through the entire thickness Sanocki, and Robert Borgstede. depths within the till. The thickness of of the aquifer, is 100 percent efficient, HYDROGEOLOGY glacial deposits is variable, generally and has a diameter of 12 inches; (3) ranging from about 100 ft in the Continental glaciation during the the well is pumped continuously for southeastern and south-central parts Pleistocene Epoch was important in 24 hours; (4) the effects of recharge, of the study area to about 300 ft in the forming the present landscape of most hydrologic boundaries, and other western part (Lindholm and others, of Minnesota, including the Wadena pumping wells are negligible. 1972). The only known bedrock out- area. Although multiple stages of gla- crop is a few miles northeast of Sta- ciation occurred, the most recent ice Modeling of Ground-Water Flow ples in T134N, R32W, section 27 advances during the late Wisconsin (Helgesen, 1977). A numerical ground-water-flow glaciation, were most influential in model was constructed and calibrated forming the current topography. Ice of The bedrock is deeply buried to aid in understanding ground-water the Hewitt phase of the Wadena lobe across most of the study area. The flow in the surficial and uppermost originated in southeastern Manitoba altitude of the bedrock surface is confined aquifers as well as interac- and flowed southeast into Minnesota about 1,200 ft in the southeastern and tions between the surficial aquifer and until it was diverted by the contempo- south-central parts of the study area the major streams. The model was raneous Rainy lobe advancing from (Lindholm and others, 1972). The calibrated for both steady-state and the northeast (Wright and Ruhe, bedrock consists largely of Precam- transient conditions using hydraulic- 1965). Ice of the Wadena lobe then brian slate, graywacke, granite, property, water-level, and water-use flowed southwest as it crossed the gneiss, and schist. Cretaceous or data compiled during this investiga- Wadena area, forming the Wadena “Cretaceous-like” sediment has been tion. The USGS modular three- drumlin field, which includes much of reported in several localities (Allison, dimensional, finite-difference ground- the study area. Drumlins are elongate 1932, p. 231). Varicolored clays, lig- water-flow model (MODFLOW) hills of till whose long axis is parallel nite, pyrite, and sand, characteristic of (McDonald and Harbaugh, 1988), was to the direction of ice movement. The Cretaceous sediments in central Min- used. eastern limit of the Wadena drumlin nesota, have been reported in the Wadena area. Precambrian slates The model was constructed and field is the St. Croix moraine in the northeastern part of the study area, occur beneath the glacial deposits in calibrated using water levels in 127 the vicinity of Staples. observation, domestic, and irrigation which is composed of younger drift wells; and stream stages at 37 sites from the Lake Superior Basin. In the Hydrogeologic Units (figs. 1 and 2). VISUAL MODFLOW northwestern part of the study area, The hydrogeologic units of pri- was used as a pre-processor to input the drumlin field is bounded by drift mary interest in the study area are the the required data, to run the MOD- of the Alexandria morainal complex. surficial aquifer, the uppermost con- FLOW simulations, and as a post-pro- Outwash deposits in the study fining units, and the uppermost con- cessor to visualize and analyze the area are part of a more extensive out- fined aquifers. The surficial aquifer results of the simulations (Guiguer wash plain (Leverett, 1932). Outwash underlies all but portions of the east- and Franz, 1999). is thickest in the swales between ern, western, and south-central parts

8 of the study area (figs. 1–3). Texture and the southern one-half of T135N generally is less than 50 ft in the of the outwash (which comprises most west of the Crow Wing, south-trend- northwestern and southeastern parts of the surficial aquifer) is predomi- ing reach of the Leaf, and Red Eye of the study area, based on 252 test- nantly medium to coarse sand, with Rivers) were in excess of 300 gal/min hole and drillers’ logs that penetrate lesser amounts of gravel and clay. The in about 60 percent of the area. High- the aquifers (fig. 5). coarsest outwash is present within capacity water-supply wells and dug Yields of several hundred gal/min former drainage courses and is most pits are located predominantly in the are common from large-diameter common in the western and southern central part of the study area south of wells completed in the uppermost parts of the study area. Coarse alluvial the Leaf River (fig. 3). Dug pits are confined aquifers. Wells in the north- deposits constitute the broad flood utilized as sources of water in areas eastern part of the study area near the plain of the Leaf River. Although the where the water table is near land sur- Crow Wing River may flow at land outwash and the alluvial deposits are face and supply yields similar to those surface. not stratigraphic time equivalents, for high-capacity wells. The uppermost confining units their similar stratigraphic position and An area of thick sand and gravel similar composition make it possible consist of clay and till and: (1) sepa- deposits near the Leaf River com- rate the surficial and uppermost con- to consider them as a single hydro- monly contains thin (less than 5 ft geologic unit. Areas of fine-grained fined aquifers in areas where the thick), discontinuous clay and till lay- surficial aquifer is present; or (2) are sand are scattered throughout the ers that may locally confine underly- study area. Fine- to medium-grained present at land surface and overlie the ing sand and gravel layers. The clay uppermost confined aquifers in areas sands predominate south of the Par- and till layers are not areally extensive tridge River between Aldrich and Sta- where the surficial aquifer is absent. or continuous and do not constitute a The surficial aquifer is underlain by ples and north of the Partridge River regional confining unit. This part of to the Leaf River flood plain. Over till or glacial lake deposits. Clay or the aquifer, hereinafter termed the silt beds remain in some areas where much of the area, the thickness of the composite zone (fig. 4), may include surficial aquifer depends upon the lakes formed during glacial reces- uppermost confined aquifers locally. sion. Most of the glacial-deposit proximity to drumlins, which have The composite zone ranges from been partially or completely buried by material underlying the surficial aqui- approximately 20 to 73 ft thick and is fer is sandy till containing varying the outwash. Data from 152 auger test probably in hydraulic connection with holes analyzed by Lindholm (1970) amounts of outwash sand and gravel. adjacent uppermost confined aquifers In moraine and till plain areas where showed that the thickness of the surfi- in some areas. cial sand and gravel in the southern the surficial aquifer is absent, sandy part of the study area ranges from Buried sand and gravel lenses till overlies the uppermost confined zero to 70 ft, with an average thick- ranging in thickness from 25 to 67 ft aquifers. The thickness of the upper- ness of 36 ft. Saturated thickness of underlie the study area in southern most confining units ranges from 4 to the surficial aquifer between the Red- Wadena County (Lindholm, 1970). 132 ft, based on 255 test-hole and eye and Crow Wing Rivers and the Although the uppermost sand and drillers’ logs that fully penetrate the area east of the Crow Wing River gravel lenses are not continuous confining units (fig. 6). The greatest ranges from zero to about 60 ft (Hel- within an altitude interval over the thicknesses (greater than 120 feet) gesen, 1977). The water table in the entire study area, some degree of occur in the northwestern, west-cen- surficial aquifer commonly is less hydraulic connection probably exists. tral, and south-central parts of the than 20 ft below land surface. Therefore, the uppermost confined study area (fig. 6), where the surficial sand and gravel lenses constitute the aquifer is absent and the confining Helgesen (1977, plate 3) calcu- uppermost confined aquifers. The units are present at land surface. The lated theoretical well yields, based on thickness of the uppermost confined uppermost confining units separating the equation of Theis (1935), ranging aquifers ranges from zero to 72 ft, the surficial and uppermost confined from less than 100 to 1,000 gal/min based on 141 test-hole and drillers’ aquifers generally are less than 50 ft for the surficial aquifer in the area logs that fully penetrate each aquifer thick. between the Redeye and Leaf Rivers (fig. 4). The thickness of the aquifers Hydraulic Properties and the Crow Wing River and the area is greatest in the south-central and east of the Crow Wing River. Lind- west-central parts of the study area, Hydraulic properties of the glacial holm (1970) estimated maximum well where thicknesses exceed 50 ft. Depth deposits are variable due to wide yields for the surficial aquifer in the to the top of the uppermost confined ranges in the composition, size, and central part of the study area (T134N aquifers ranges from 23 to 132 ft, but degree of sorting of the material that

9 95°15' 95°07'30" 95° 94°52'30" 94°45'

46°37'30" 6 Ck. 1 6 Sebeka 1 6 1 6 1 6 1 Red Beaver Creek Strike Lake T Granning 136 Lake Oylen N Eye Farnham

Creek

Crow Hay Creek 31 36 31 36 31 36 31 36 31 36 Creek Martin Creek Blue 6 1 6 1 6 1 6 Sand 1 6 1 River Lake Tower Sugar Creek Mud Creek Lake Little Farnham T 46°30' OTTER TAIL WADENA COUNTY COUNTY Lake CASS 135 N N. River COUNTY Bluff Leaf River Pulver Creek Creek Bluffton Leaf Lake

Creek 31 36 31 36 31 36 31 36 31 Iron 36 Ck. Radabaugh 6 1 6 1 1 6 1 1 Wadena 6 Lake6

River Ck. Rice Simon South

Lovejoy Lake Creek Creek Lake Lake Wing T

Whiskey Farber Cat 134 Lake Lake N Union Verndale Johnson Wing River Lake Dog Lake

31 36 31 31 Aldrich 46°22'30" 36 36 31 Creek 36 31 36 Bluff

6 6 Benz 1 1 1 6 1 6 Staples 1 6 Dower Lake Moran Lake River

Oak Stones R. Tucker Creek Edwards Lake Hayden Lake Hewitt Lake T TODD Hayden Lake Jacobson 133 Munn Lake River

COUNTY Lawrence N South

Bear ge Lake Lake Prairie Jasmer Partridge Lake

Long Partrid

Creek S. 31 36 31 36 31 36 31 36 31 36

R 36 W R 35 W R 34 W R 33 W R 32 W

Base from U.S. Geological survey digital data 1:100,000, 1972 0 5 10 MILES US Albers Equal Area Projection standard parallels 29°30' and 45°30', central meridian -95° 0 5 10 KILOMETERS

EXPLANATION

Extent of surficial aquifer

Area where surficial aquifer is absent

High capacity (municipal, commercial, and irrigation) water-supply wells completed in surficial and uppermost confined aquifers and dug pits

Figure 3. Location of high-capacity water-supply wells and dug pits, and extent of surficial aquifer, southern Wadena County and parts of surrounding counties, Minnesota.

10 95°15' 95°07'30" 95° 94°52'30" 94°45'

46°37'30" 6 Ck. 1 6 1 6 1 Sebeka 6 1 6 30 1 Red 10 Beaver Creek 20 Strike 20 Lake 10 T Granning 136 10 10 Lake Oylen N Eye Farnham

20 Creek

Crow Hay Creek 31 36 31 36 31 36 31 36 31 36 Creek Creek

10 30 Martin 10

Blue 10 6 1 6 1 20 6 WADENA 1 6 Sand 1 6 1 COUNTY River Lake Tower OTTER TAIL 20 Sugar Creek Mud Creek COUNTY Lake Little 10 Farnham T 46°30' 20 40 70 Lake CASS 135

30 N

10 10 60 Bluff River COUNTY 50 Leaf 40 River Pulver 30 Creek Creek Bluffton Leaf 70 Lake 20 Creek 31 36 31 60 36 31 36 31 36 31 Iron 36 10 Ck. Radabaugh 6 1 6 6 1 50 40 1 1 6 1 Lake 30 10 Wadena 6 10 10 0 50 20 1 River Ck. Rice Simon South

20 40 Lovejoy Lake20 Creek Creek Lake Lake Wing T Whiskey 30 Cat Farber 134 Lake Lake 30 10 N Union Verndale Johnson Wing River Lake Dog 50 40 10 Lake 20 31 36 31 36 31 Aldrich 46°22'30" 20 36 31 Creek 36 31 36 Bluff 10 50 20 6 6 Benz 1 1 1 6 1 6 40 Staples 1 6 40 Dower Lake 40 40 Moran 30 Lake River 30 Oak 20 50 Stones R. Tucker Creek Edwards Lake Hayden Lake Hewitt Lake T Jacobson Hayden Lake 10 133 30 30 20 Munn Lake River

20 Lawrence30 N South

Bear ge TODD Lake Prairie 20

20 Lake Jasmer Partridge COUNTY 10 Lake 10 Long Partrid 30 Creek S. 31 36 31 36 31 36 31 36 31 36

0 5 10 KILOMETERS

EXPLANATION

Large area where uppermost confined aquifers are absent

Boundary of composite zone

10 Line of equal thickness of composite zone and uppermost confined aquifers Hachures indicate thickness less than 10 feet. Interval 10 feet. Datum is sea level

Well log used for control

Well log used for control--Uppermost confined aquifers are absent

Figure 4. Thickness of composite zone and uppermost confined aquifers, southern Wadena County and parts of surrounding counties, Minnesota.

11 95°15' 95°07'30" 95° 94°52'30" 94°45' 46°37'30" 6 60 Ck. 20 1 6 Sebeka 1 6 1 6 1 6 80 1 60 Red Beaver Creek 80 60 Strike 100 40 100 40 Lake 80 100 T

80 Granning 60 136

80 100 120 Lake Oylen 60 N 60 Eye Farnham

40 80 Creek 100 Crow Hay Creek 31 36 31 36 31 36 31 36 31 40 36 80 Creek 80 Martin Creek Blue 60 1 6 120 6 1 6 6 40 60 80 80 1 100 Sand 1 6 80 1 60 40 60 River Lake Tower 60 Sugar OTTER TAIL 60 Creek Mud Creek 80 80 Lake COUNTY Little 80 T 46°30' 40 60 Farnham 120 Lake CASS 135 N Bluff River COUNTY 80 Leaf River 40 Pulver 100 WADENA 60 Creek Creek Bluffton Leaf COUNTY Lake 60 Creek 31 40 36 31 40 36 31 8036 31 36 31 Iron 36 20 Ck. Radabaugh 6 1 6 1 60 1 6 1 1 Wadena 60 6 Lake6 40 60 80

80 River Ck. Rice Simon South

60 Lovejoy Lake

80 Creek Creek Lake Lake Wing T

Whiskey Farber Cat 134 Lake 60 Lake N Union Verndale Johnson 120 Wing River Lake 80 80 Dog 80 80 Lake 60 40 31 36 31 31 Aldrich 46°22'30" 36 60 36 31 Creek 36 31 36 100 Bluff 60 60 6 1 6 80 Staples Benz 1 1 406 1 6 1 6 80 20 Dower Lake 40 Moran 40 Lake River

60 Oak 60 R. Tucker Stones Creek Edwards 40 Lake 60 Hayden Lake 100 Hewitt Lake40 T Hayden Lake Jacobson 133 Munn Lake River 60 Lawrence40 N South Bear 80 80 60 Lake TODD Lake Prairie Jasmer Partridge COUNTY40 Lake

Long

Partridge 120 120 80 20 Creek 40 S. 31 36 31 36 100 31 36 31 36 31 20 36 R 36 W R 35 W R 34 W R 33 W R 32 W Base from U.S. Geological survey digital data 1:100,000, 1972 US Albers Equal Area Projection standard parallels 29°30' and 45°30', central meridian -95° 0 5 10 MILES

0 5 10 KILOMETERS

EXPLANATION

Extent of surficial aquifer

Area where surficial aquifer is absent

Large area where uppermost confined aquifers are absent

Boundary of composite zone

20 Line of equal depth to top of uppermost confined aquifers--Hachures indicate decreasing depth to top of aquifers. Interval 20 feet. Datum is sea level

Well log used for control

Well log used for control--Uppermost confined aquifers are absent

Figure 5. Depth to top of uppermost confined aquifersand extent of surficial aquifer , southern Wadena County and parts of surrounding counties, Minnesota.

12 95°15' 95°07'30" 95° 94°52'30" 94°45'

46°37'30" 6 Ck.

20 1 6 Sebeka 1 6 1 6 1 6 80 1 60 Red 80 60 Beaver Creek 80 Strike 40 100 Lake 40 T 100 60

80 Granning 136

80 100 120 60 Lake Oylen N Eye Farnham 40 40 80 Creek

100 Crow Hay60 60 Creek 31 36 31 36 31 40 36 31 36 31 36 Creek Martin Creek Blue 80 1 6 6 180 80 80 80 80 6 1 6 Sand 1 6 1 40 60 20 60 80 60 40 River Lake Tower 60 40 Sugar OTTER TAIL 60 Creek Mud Creek COUNTY Lake Little 80 Farnham T 46°30' 40 120 Lake CASS 135 N Bluff River COUNTY 80 Leaf 60 River 20 Pulver 100 60 Creek Creek Bluffton Leaf40 WADENA Lake COUNTY Creek 31 36 31 20 20 36 31 36 31 36 31 40Iron 36 Ck. 60 Radabaugh 6 1

6 1 1 6 1 1 20 20 20 20 60 80 6 Lake 40 Wadena 40 6 80

River Ck. Rice 60 Simon South

20 Lovejoy Lake

Creek 202020 80Creek Lake 20 Lake Wing T

Whiskey Farber Cat 134 40 Lake Lake N Union Verndale Johnson 120 Wing River Lake 40 40 40 40 20 Dog 40 40 Lake 60 20 31 36 31 60 31 Aldrich 46°22'30" 36 36 31 Creek 60 36 31 36 Bluff 20 100 6 201 6 Staples Benz 1 1 6 1 6 1 20 6 80 Dower Lake Moran 20 Lake River 80

Oak Stones R. Tucker 60 Creek Edwards Lake Hayden Lake 100 Hewitt Lake40 T 40 Hayden Lake 40 100 40 Jacobson 40 133 Munn Lake River

60 60 Lawrence N South

80 80 80 80 Bear ge Lake TODD Lake20 Prairie Jasmer Partridge 40 COUNTY Lake Long

80 Partrid

120 120 100 Creek S. 31 36 31 36 20 31 36 31 36 31 36

0 5 10 KILOMETERS

EXPLANATION

Extent of surficial aquifer

Area where surficial aquifer is absent

Large area where uppermost confined aquifers are absent

Boundary of composite zone

20 Line of equal thickness of uppermost confining units-- Hachures indicate declining thickness. Interval 20 feet. Datum is sea level

Well log used for control

E Well log used for control--Uppermost confined aquifers are absent

Figure 6. Thickness of uppermost confining unitsand extent of surficial aquifer , southern Wadena County and parts of surrounding counties, Minnesota.

13 comprise the deposits. Consequently, described by Rasmussen and pal, golf course and landscaping, and glacial deposits can be either an aqui- Andreasen (1959). The method domestic wells. fer or a confining unit. Field tests assumes that all water-level rises in a Water levels in the aquifers fluc- were not conducted for this investiga- well result from areal recharge. A spe- tuate seasonally in response to sea- tion to determine the hydraulic prop- cific yield value of 0.20 was assumed sonal variations in recharge and erties of aquifers and confining units. in the areal recharge calculations. discharge (fig. 9). Ground-water lev- Reported values of hydraulic conduc- Estimated areal recharge ranged from els commonly rise in spring, when tivity, transmissivity, specific yield, 6.0 to 23.0 in. during 1998, and aver- areal recharge is greatest because of and storage coefficient are shown in aged 13.9 in. Estimated areal recharge snowmelt, spring rain, and minimal table 2. ranged from 6.2 to 17.3 in. during evapotranspiration losses. Ground- Hydrology 1999, and averaged 11.5 in./yr. These water levels generally decline in sum- recharge rates generally are greater Ground water generally moves mer because discharge by evapotrans- than those reported by previous inves- from high morainal areas toward piration discharges to streams, and tigations (table 2). The areal recharge major streams, which flow across withdrawals by wells exceed rates estimated from hydrographs for topographically lower outwash plains. recharge. Net recharge to the aquifers wells located near the Leaf River were The regional direction of flow in the also occurs in the fall of most years, greater than for other areas. Estimated surficial aquifer is toward the Leaf due to rainfall and low evapotranspi- areal recharge rates near the Leaf and Crow Wing Rivers and, to a lesser ration rates. River during 1998–99 ranged from extent, toward the Wing, Partridge, The available hydrologic data in 10.6 to 23.0 in./yr, with an average of Red Eye, and Long Prairie Rivers and near the study area indicate that 15.5 in./yr. Estimated areal recharge (fig. 7). Locally, flow is also toward the ground-water levels fluctuate in rates for other areas generally ranged smaller streams and lakes. The response to seasonal variations in from 6 to 12 in./yr. regional direction of flow in the recharge and discharge around mean uppermost confined aquifers is to the Sources of water to the uppermost water levels that remain relatively east, southeast, and southwest toward confined aquifers are leakage of water constant in time. The ground-water the Crow Wing River in the eastern through overlying till and clay and system is in a dynamic equilibrium, or part of the study area and toward the ground-water flow from aquifers steady-state condition, in which dis- Leaf River in the western part (fig. 8). adjoining the northeastern, northwest- charges from the system are balanced A steep hydraulic gradient (40 to 60 ern, and southwestern study area by recharge to the system. Ground- ft/mi) exists in the northwestern part boundaries. Delin (1987 and 1988) water levels may rise or decline for a of the study area near the boundaries suggested that leakage through over- period of a few years in response to of the Leaf and Red Eye River val- lying till in west-central Minnesota periods of above-normal or below- leys. Potentiometric surface maps ranges from 3 to 6 in./yr, based on normal precipitation, but long-term (figs. 7 and 8) indicate that the Crow hydrograph and ground-water-flow declines in levels have not occurred in Wing and Leaf Rivers are major dis- model analysis (table 2). Leakage the study area. Winter water levels charge areas for the surficial and rates through till computed using from a given year approximate long- uppermost confined aquifers. Darcy’s Law, however, were much term steady-state conditions. Recharge to the surficial aquifer lower, 0.06–1.60 in./yr (Delin, 1988). Ground-Water Withdrawals occurs by infiltration of precipitation to the saturated zone (areal recharge). Discharge from the surficial aqui- Ground water is the primary Helgesen (1977) considered an areal fer is: (1) by withdrawals from irriga- source of water for irrigation, munici- recharge rate of about 5 in./yr to be tion, municipal, commercial, and pal, commercial, and domestic uses in representative of long-term conditions domestic wells; (2) by ground-water the study area. Glacial-deposit aqui- for the area between the Redeye and evapotranspiration in areas where the fers are the source of water for all Crow Wing Rivers and the area east water table is within about 5 ft of land municipal supply wells in the study of the Crow Wing River. Ground- surface; and (3) to streams. Water in area. There were 11 municipal water- water recharge rates in the study area the uppermost confined aquifers flows supply wells and 199 irrigation wells for 1998 and 1999 were estimated toward the river valleys, where it dis- that withdrew water during 1997–98 from monthly water-level measure- charges to the overlying surficial (table 3). Nine of the 11 municipal ments for 17 observation wells com- aquifer. Discharge from the upper- wells are completed in the uppermost pleted in the surficial aquifer, based most confined aquifers also is by confined aquifers. Most permits for on the method of hydrograph analysis withdrawals from irrigation, munici- irrigation have been issued since

14 Table 2. Reported values of hydraulic properties and fluxes, southern Wadena County and parts of surrounding counties, Minnesota [in./yr, inches per year; ft, feet; ft/d, feet per day; ft2/d, feet squared per day; gpd/ft, gallons per day per foot; >, greater than. Number in parentheses refers to number of aquifer tests conducted] Method used to determine Hydraulic property or flux Area value(s) applies to Single or mean value Range of values value(s) Horizontal hydraulic conductivity (ft/d) [gpd/ft2] Glacial-deposit aquifers Freeze and Cherry (1979) Not specified Reported values 101–104 Surficial aquifers Lindholm (1970) Wadena area Aquifer-tests (3) 193–321 [1,440–2,400] Helgesen (1977) T134N,R32W, section 7 Aquifer test 320 Staples Irrigation Center Aquifer test 325 Myette (1984) (located about 5 miles northwest of Staples) Confined aquifers West-central Minnesota Aquifer tests and specific 10–750 Delin (1988) capacities Lindholm (1970) Wadena area Aquifer test 341 [2,550] Glacial-deposit confining units Norris (1962) South Dakota Reported values 9.4x10-3 4.0x10-5–6.7x10-2 Delin (1988) West-central Minnesota Slug tests (8) 1.4x10-1 North-central Minnesota Ground-water-flow model 0.1–1.0 Stark and others (1991) analysis Transmissivity (ft2/d) [gpd/ft] Surficial aquifers Crow Wing River Watershed Aquifer tests and specific 1,337–13,369 Lindholm and others (1972) capacities [10,000–100,000] Verndale area Aquifer tests and specific >4,011[>30,000] Lindholm and others (1972) capacities Lindholm (1970) Wadena area Aquifer test (3) 8,690–10,963 [65,000–82,000] Wadena area Aquifer test, laboratory analy- 2,005–16,043 Lindholm (1970) ses, and published data [15,000–120,000] Helgesen (1977) T134N,R32W, section 7 Aquifer test 10,700 Staples Irrigation Center Aquifer test 9,800 Myette (1984) (located about 5 miles northwest of Staples) Confined aquifers Lindholm and others (1972) Crow Wing River Watershed Specific capacities 134–1,337 [1,000 - 10,000] Lindholm (1970) Wadena area Aquifer test 15,642 [117,000] Vertical hydraulic conductivity (ft/d) [gpd/ft2] Glacial-deposit confining units Freeze and Cherry (1979) Not specified Reported values 10-6–1 Delin (1988) West-central Minnesota Aquifer tests (4) 4.0x10-1 8.6x10-6–1.8 Miller (1982) Northwestern Minnesota Aquifer test 1.8x10-2 Specific yield Heath (1983) Not specified Reported values 0.10–0.30 Lindholm and others (1972) Verndale area Aquifer tests 0.15 Lindholm (1970) Wadena area Aquifer test (3) 0.11–0.18 Helgesen (1977) T134N,R32W, section 7 Aquifer test 0.18

15 Table 2. Reported values of hydraulic properties and fluxes, southern Wadena County and parts of surrounding counties, Minnesota (Continued) [in./yr, inches per year; ft, feet; ft/d, feet per day; ft2/d, feet squared per day; gpd/ft, gallons per day per foot; >, greater than. Number in parentheses refers to number of aquifer tests conducted] Method used to determine Hydraulic property or flux Area value(s) applies to Single or mean value Range of values value(s) Staples Irrigation Center Aquifer test 0.185 Myette (1984) (located about 5 miles northwest of Staples) Storage coefficient Glacial-deposit confined aquifers Lindholm (1970) Wadena area Aquifer test 1.4x10-2 Freeze and Cherry (1979) Not specified Reported values 5.0x10-5–5.0x10-3 Glacial-deposit confining units Southwestern Minnesota Ground-water-flow model 1.0x10-5–5.0x10-4 Lindgren and Landon (2000) analysis Areal recharge to surficial aquifers (in./yr) Lindholm (1970) Wadena area Hydrograph analysis 4.8–12.0 Helgesen (1977) Central Minnesota Hydrograph analysis 5.1 Lindgren and Landon (2000) Southwestern Minnesota Hydrograph analysis 2.9–8.2 Recharge to confined aquifers by leakage through till (in./yr) Delin (1986) Western Minnesota Computed using Darcy’s Law 0.4–3.4 Delin (1988) West-central Minnesota Computed using Darcy’s Law 0.06–1.60 West-central Minnesota Hydrograph analysis and 3.0–6.0 Delin (1987 and 1988) ground-water-flow model analysis

1960. Fifty-six percent (111) of the study area near the Leaf River where in the aquifers are similar in most of irrigation wells are completed in the the uppermost confining units are the study area. The vertical hydraulic surficial aquifer. Water was pumped comparatively thin and discontinuous. gradient is generally downward at the for irrigation purposes from 47 dug In this area, the surficial and upper- USGS well sites with nested wells, but pits, which are equivalent to wells most confined aquifers cannot be of small magnitude (less than 0.4 ft of completed in the surficial aquifer. The clearly separated and for the purposes hydraulic head difference), indicating locations for which irrigation permits of this report are considered a single minimal leakage between the aquifers. have been issued are largely within the aquifer (composite zone, fig. 6) The Near the major streams, however, areas of surficial outwash. Some irri- composite zone is probably in hydrau- water levels in nested wells indicate gation wells are completed in the lic connection with adjacent upper- relatively strong upward vertical gra- uppermost confined aquifers in most confined aquifers. dients. The average 1998–99 hydrau- T133N, R35W, where the uppermost The uppermost confining units lic head differences were as much as confining units are present at land sur- separating the surficial and uppermost 10.8 ft near the Leaf River, 4.2 ft near face and the surficial aquifer is absent. confined aquifers consist of sandy the Crow Wing River, 3.9 ft near the Wing River, 2.3 ft. near the Red Eye Vertical Hydraulic Connection clay and are generally from 20 to 80 ft thick outside the boundaries of the River, and 1.7 ft near the Partridge between aquifers composite zone (fig. 6). Thicknesses River. The vertical hydraulic connection of less than 20 ft occur west of Stream-Aquifer Leakage between the surficial and uppermost Wadena, north of Verndale, and near confined aquifers is dependent on the the Crow Wing River. The greatest Stream-discharge measurements thicknesses and vertical hydraulic potential for hydraulic connection and indicated that the Crow Wing River in conductivities of the uppermost con- leakage between the aquifers is where the study area may have both gaining fining units that separate the aquifers. the uppermost confining units are less and losing reaches, but is a gaining The primary area of hydraulic connec- than 20 ft thick. stream overall (table 1). The measured tion between the aquifers, with pre- Water levels in wells completed in gains and losses for the Crow Wing sumably the greatest amount of the surficial and uppermost confined River, other than for reach SW1-SW2 leakage, is in the central part of the aquifers indicate that hydraulic heads in November 1999, were less than the

16 Nimrod 95°15' 95°07'30" 95° 94°52'30" 94°45' 46°37'30" 6 1340 Ck. 1 6 Sebeka 1 6 1 6 1 6 1 Red Beaver

1320 Creek Strike Lake T Granning 136 Lake Oylen N Eye Farnham

Creek

Crow Hay Creek 31 36 31 36 31 36 31 36 31 36 Creek Creek 1300 Martin Blue 6 1 6 1 6 1 6 Sand 1 6 1 River Lake Tower Sugar Creek Mud Creek 1280 Lake Little Farnham T 46°30' OTTER TAIL WADENA 1260 COUNTY COUNTY Lake CASS 135 N Bluff River COUNTY Leaf River Pulver Creek Creek Bluffton Leaf Lake

Creek 31 36 31 36 31 36 31 36 31 Iron 36 Ck. 1300 Radabaugh 6 1 6 6 1 1 1 6 1 Lake Wadena 1320 6

River Ck. Rice Simon South

Lovejoy Lake

Creek

1340 Creek Lake Lake Wing T

Whiskey Farber Cat 134 Lake 1360 Lake N Union Verndale Johnson Wing River 1260 Lake 1240 Dog 1280 Lake

31 36 31 31 Aldrich 46°22'30" 36 36 31 Creek 36 31 36 Bluff 1380 6 6 Benz 1 1 1 6 1 6 Staples 1 6 Dower Lake Moran

Lake River

1220

Oak Stones R. Tucker Creek Edwards Lake Hayden Lake Hewitt Lake T 1400 TODD Hayden Lake Jacobson 133 Munn Lake River

COUNTY Lawrence N South

Bear ge Lake Lake Prairie Jasmer Partridge Lake Long 1415 Partrid Creek S. 31 36 31 36 31 36 31 36 31 36

0 5 10 KILOMETERS EXPLANATION Extent of surficial aquifer

Area where surficial aquifer is absent

Boundary of composite zone

1300 Measured potentiometric contour--Shows altitude at which level would have stood in tightly cased wells open to the surficial aquifer. Dashed where inferred. Interval varies. Datum is sea level

Generalized direction of ground-water flow

Well used for control

Stream-stage measurement site used for control

Figure 7. Altitude of potentiometric surface of surficial aquifer, December 1998,and extent of surficial aquifer, southern Wadena County and parts of surrounding counties, Minnesota.

17 95°15' 95°07'30" 95° 94°52'30" 94°45'

46°37'30" 6 Ck. 1 6 Sebeka 1 6 1 6 1 6 1 Red Beaver Creek Strike Lake T Granning 136 Lake Oylen N Eye Farnham

Creek

Crow 1420 Hay Creek 31 36 31 36 31 36 31 36 31 36 Creek Creek 1400 Martin Blue 6 1 6 1 1380 6 1 6 Sand 1 6 1 1360 River Lake Tower

Sugar 1320

Creek Mud Creek1320 1340 Lake 1320 Little Farnham T 46°30' OTTER TAIL WADENA COUNTY COUNTY Lake CASS 135 N Bluff River COUNTY Leaf 1300 River Pulver Creek Creek Bluffton Leaf Lake

Creek 31 36 31 36 31 36 31 36 31 Iron 36 Ck. Radabaugh 6 1 6 1 1 6 1 1 Wadena 6 Lake6 1280 1260

River Ck. Rice Simon South

Lovejoy Lake Creek Creek Lake Lake Wing T

Whiskey Farber Cat 134 Lake 1240 Lake N Union Verndale Johnson Wing River Lake Dog Lake

1260

31 1280 36 31 31 Aldrich 46°22'30" 36 36 31 Creek 36 31 36 Bluff

6 1340 Benz 6 1320 1 1 1 6 1 6 Staples 1 6 Dower Lake 1360 1300 Moran Lake River

Oak Stones R. Tucker 1380 Creek Edwards Lake Hayden Lake Hewitt Lake T TODD Hayden Lake Jacobson 133 Munn Lake River 1400 COUNTY Lawrence N South Bear Lake Lake Prairie Jasmer Partridge Lake

Long Partridge

Creek S. 31 36 31 36 31 36 31 36 31 36

0 5 10 KILOMETERS

EXPLANATION

Large area where uppermost confined aquifers are absent

Boundary of composite zone

1300 Measured potentiometric contour--Shows altitude at which level would have stood in tightly cased wells open to the uppermost confined aquifer. Dashed where inferred. Interval 20 feet. Datum is sea level

Generalized direction of ground-water flow

Well used for control

Figure 8. Altitude of potentiometric surface of uppermost confined aquifers, December 1998, southern Wadena County and parts of surrounding counties, Minnesota.

18 magnitude of the estimated measure- high degree of vertical hydraulic con- Numerical Model Description ment uncertainty of 5–8 percent. The nection between the surficial and The study area was subdivided discharge measurements for the Leaf, uppermost confined aquifer at the into rectangular finite-difference grid Wing, and Partridge Rivers indicated aquifer-test site. Areal variations in cells within which the properties of that these rivers are all gaining the magnitude of theoretical maxi- the hydrogeologic unit represented are streams for all measured reaches. The mum well yields shown on figure 10 assumed to be uniform. The center of measured gains for these stream are caused predominantly by areal a grid cell is referred to as a node and reaches were appreciably greater than variations in aquifer thickness (fig. 4). represents the location for which the the estimated measurement uncer- The areas of greatest theoretical maxi- hydraulic head is computed by the tainty of 5–8 percent, except for reach mum well yields coincide with areas model. The uniformly-spaced finite- SW9-SW10 of the Leaf River. The of greatest aquifer thickness and difference grid has 96 rows and 120 discharge measurements for the Red transmissivity. High-capacity wells columns (fig. 11). The dimensions of Eye River indicated that the river is a generally are located in these areas. each grid cell are one-quarter mile gaining stream overall, but possibly (1,320 ft) along rows and columns. with a losing reach near its confluence No aquifer or well fully satisfies Notation of the form (11, 24), where with the Leaf River. The measured the assumptions inherent in the the first number in parentheses indi- loss in streamflow in August 1998 is method used to estimate theoretical cates the row and the second number minimally greater than the estimated maximum well yields. Local varia- indicates the column, is used to refer measurement uncertainty of 5 percent. tions in aquifer hydraulic properties, recharge, proximity of the well to to the location of an individual cell The measured streamflows during other pumping wells, effects of hydro- within the grid. The area modeled was November 1999 were much greater logic boundaries (for example, rivers), extended away from the area of exten- than in August 1998 (table 1). The well diameter and efficiency, and sive irrigation in southern Wadena anomalously high measured gain in duration of pumping will cause differ- County by sufficient distances to min- streamflow for reach SW1-SW2 of ences from the values shown on figure imize boundary effects. the Crow Wing River during Novem- 10. The theoretical maximum well The ground-water system was ber 1999 probably is due to wet con- yields for the uppermost confined subdivided vertically into three layers, ditions that developed as a result of aquifers are intended to show only corresponding to generally horizontal rainfall during the time of the mea- general conditions and relative differ- hydrogeologic units. The altitudes of surements and may include a compo- ences in water-yielding capability. the layer tops and layer bottoms were nent of overland runoff. The lower The map cannot be used for accurate specified for each model cell for the streamflows measured during August estimation of well yields at a given three layers. The thickness of a cell 1998 are probably more representa- location. Determination of site-spe- representing a hydrogeologic unit is tive of base-flow conditions, and cific well yields requires hydraulic incorporated in the transmissivity therefore stream-aquifer leakage. testing such as aquifer tests. term for the cell. Simulation of leak- Theoretical Maximum Well Yields in age of water between model layers is SIMULATION OF GROUND- dependent on the thicknesses and ver- Uppermost Confined Aquifers WATER FLOW tical hydraulic conductivities of the The theoretical maximum well adjacent layers. A detailed discussion yields for the uppermost confined A conceptual model is a qualita- of leakage between model layers can aquifers range from less than 175 tive description of the known charac- be found in McDonald and Harbaugh gal/min to greater than 3,000 gal/min teristics and functioning of the (1988). (fig. 10). The distribution of theoreti- glacial-deposit aquifers. It was formu- The hydrogeologic units repre- cal maximum well yields is derived lated from knowledge of the hydro- sented in the ground-water-flow from aquifer thickness, a uniform hor- geologic setting, aquifer model are, in descending order: (1) izontal hydraulic conductivity of 150 characteristics, distribution and the surficial aquifer (layer 1), (2) the ft/d, and available drawdown. The amount of recharge and discharge, confining units underlying the surfi- value of 150 ft/d was derived from and aquifer boundaries. A numerical cial aquifer (layer 2), and (3) the numerical ground-water-flow model model of ground-water flow was con- uppermost confined aquifers (layer 3). analysis and represents an average, structed based on this conceptual Cells in model layers 1 and 3 gener- regional value. The comparatively model using the MODFLOW code ally were assigned the hydrogeologic high value reported by Lindholm developed by McDonald and Har- properties of sand and gravel. Cells in (1970) (table 2) is probably due to a baugh (1988). model layer 2 were assigned the

19 1,309 SITE 12N 1,308

1,307

1,306

ABOVE SEA LEVEL WATER LEVEL, IN FEET WATER 1,305

1,304 1,331 SITE 14 1,330

1,329

1,328

ABOVE SEA LEVEL WATER LEVEL, IN FEET WATER 1,327

1,326 1,361 1,360 F. Schmidt 1,359 1,358 1,357 1,356 1,355

ABOVE SEA LEVEL

WATER LEVEL, IN FEET WATER 1,354 1,353 1,352 1,377 1,376 R. Wells 1,375 1,374 1,373 1,372 1,371

ABOVE SEA LEVEL 1,370 WATER LEVEL, IN FEET WATER 1,369 1,368 1,367 A MJ J A S OND J FMAMJ J A SOND J FMAMJ J A S OND 1997 1998 1999 EXPLANATION MEASURED SIMULATED Surficial Surficial Confined Confined

Figure 9. Measured and simulated hydraulic heads for selected observation wells completed in surficial and uppermost

20 1,379 B. Swenson 1,378

1,377

1,376

ABOVE SEA LEVEL WATER LEVEL, IN FEET WATER 1,375

1,374 1,289 SITE 10 1,288

1,287

1,286

1,285

ABOVE SEA LEVEL

WATER LEVEL, IN FEET WATER 1,284

1,283 1,284 Site 15 1,283

1,282 Surficial and confined together

1,281

ABOVE SEA LEVEL

WATER LEVEL, IN FEET WATER 1,280

1,279 1,239 Site 2 1,238

1,237

1,236

1,235

ABOVE SEA LEVEL

WATER LEVEL, IN FEET WATER 1,234

1,233 A MJ J A S OND J FMAMJ J A SOND J FMAMJ J A S OND 1997 1998 1999

confined aquifers, transient simulation 1998-99, southern Wadena County and parts of surrounding counties, Minnesota.

21 hydrogeologic properties of clay and simulated across the north-central water flow across boundaries was till. boundary because the predominant simulated for model layer 2. The flow directions are toward the Crow boundaries for model layer 3 coincide The transmissivities associated Wing and Red Eye Rivers, approxi- with the boundaries of the study area with the model cells for layer 1 vary mately parallel to the boundary. Simi- (fig. 12c). Ground-water flow near the as the saturated thicknesses vary. The larly, no ground-water flow is boundaries is approximately parallel transmissivities assigned to the model simulated across the southwestern to the boundaries, except for the cells for layer 2 and layer 3 are con- boundary because the predominant northwestern, northeastern, and south- stant in time. flow direction is toward Oak Creek, western boundaries; therefore, no Ideally, all model boundaries approximately parallel to the bound- ground-water flow across the bound- should be located at the physical lim- ary. The southeastern boundary is par- aries was simulated. Hydraulic heads its of the aquifer system or at other tially defined by the Long Prairie were specified (constant-head bound- hydrologic boundaries, such as a River, which serves as a discharge ary condition) for the northwestern, major river. Practical considerations, area (sink) for the surficial aquifer. No northeastern, and southwestern such as limitations concerning the size ground-water flow is simulated across boundary cells, based on measured of the area modeled, may necessitate the portions of the southeastern water levels in those areas. These the use of arbitrarily imposed model boundary west of the Long Prairie boundaries are far enough away from boundaries where the natural hydro- River and between the Long Prairie the areas of primary interest (irriga- logic boundaries lie outside the model and Crow Wing Rivers because the tion areas in southern Wadena area. The boundaries for model layer predominant flow is approximately County) to minimize boundary effects 1 are located at the physical limits of parallel to these boundaries. The on model-computed hydraulic heads the aquifer, except for the north-cen- boundaries for model layer 2 were and flows in the areas of primary tral, southwestern, and southeastern imposed to coincide with the bound- interest. boundaries (fig. 12a). Ground-water aries for model layer 1 (fig. 12b). flow was not simulated across the Because flow in confining units is A specified-flux boundary was boundaries. No ground-water flow is predominantly vertical, no ground- used to represent areal recharge to

Table 3. Ground-water withdrawals during 1997-98 in southern Wadena County and parts of surrounding counties, Minnesota [Mgal, million gallons; --, no ground-water withdrawals. Ground-water withdrawals were obtained from the Mnnesota Department of Natural Resources]

Withdrawals Aquifer and well type Number of wells 1997 (Mgal) 1998 (Mgal) Surficial aquifer Irrigation wells 111 833.48 1441.76 Municipal wells 2 19.48 19.41 Commercial wells 2 -- 10.51 Subtotal 115 852.96 1471.68 Dug pits 47 329.76 431.28 Total 162 1182.72 1902.96

Uppermost confined aquifers Irrigation wells 88 899.80 1437.69 Municipal wells 9 428.61 456.39 Other wells1 3 25.87 31.69 Total 100 1354.28 1925.77

1Golf course and landscaping wells

22 95°15' 95°07'30" 95° 94°52'30" 94°45'

1,000 46°37'30" 6 Ck. 1 6 1 6 1 6 1 Sebeka 1 6 Red 175 Beaver 500 Creek Strike 500 Lake 175 T Granning 136 175 175 Lake Oylen N Eye Farnham

500 Creek

Crow Hay Creek 31 36 31 WADENA 36 31 36 31 36 31 36 Creek Creek

175 COUNTY Martin

175 1,000 175 Blue 500 6 1 6 1 6 1 6 Sand 1 6 1 1,000 River Lake Tower OTTER TAIL 1,500 500 Sugar COUNTY Creek Mud Creek Lake Little 500 175 Farnham T 46°30' 500 1,000 Lake CASS 135 2,000 N Bluff River 2,500 2,000 COUNTY 1,000 Leaf 1,500 3,000 River Pulver Creek Creek Bluffton175 Leaf Lake 175 Creek 31 36 31 1,000 500 36 31 36 31 36 31 Iron 36 Ck. Radabaugh 6 1 6 6 1 1 1 6 1 Lake 2,000 175 1,500 6 1,000 Wadena 2,000 500 175

River 175 Ck. 175 175 Rice Simon South 500

500 1,500 Lovejoy Lake Creek Creek Lake Lake Wing T Whiskey 1,000 Farber Cat 134 Lake Lake 175 N Union Verndale Johnson 1,000 Wing River Lake Dog 2,000 175 Lake 1,5001,500 500 500 31 2,000 36 31 31 36 Aldrich36 31 Creek 46°22'30" 36 31 17536 Bluff

50020 6 6 Benz 1 1 1 6 1 6 1,500 Staples 1 6 1,500 Dower Lake1,500 Moran 1,000 Lake River 1,000 2,000 Oak 500 Stones R. Tucker Creek Edwards Lake Hayden Lake Lake T Hewitt Hayden Lake 175 500 Jacobson 133 1,000 1,000 Munn Lake 500 River Lawrence1,000 N

South Bear TODD Lake Prairie 500

500 Lake 175 Jasmer Partridge COUNTY 175 Lake Long Partridge 1,000 Creek S. 31 36 31 36 31 36 31 36 31 36

0 5 10 KILOMETERS

EXPLANATION

Large area where uppermost confined aquifers are absent

Boundary of composite zone

500 Line of equal theoretical maximum yield assuming an efficient fully penetrating well and available drawdown defined as the difference between static water level in a well and bottom of uppermost confined aquifer penetrated. Hachures indicate yield less than 175 or 500 gallons per minute. Interval, in gallons per minute, varies

Figure 10. Theoretical maximum yield of wells completed in uppermost confined aquifers, southern Wadena County and parts of surrounding counties, Minnesota.

23 COLUMN 1 10 20 30 40 50 60 70 80 90 100 110 120

1 Ck. Sebeka Red Beaver Creek Strike Lake

Granning Lake Oylen Eye Farnham

Creek

20 Crow Hay Creek

Creek Martin Creek Blue Sand River Lake Tower Sugar 30 Creek Mud Creek Lake Little OTTER TAIL WADENA Farnham COUNTY COUNTY Lake CASS

40 Bluff River COUNTY Leaf River Pulver Creek Creek Bluffton Leaf Lake

Creek Iron Ck. Radabaugh 50 Lake ROW Wadena

River Ck. Rice Simon South

Lovejoy Lake Creek Creek Lake Lake Wing

Whiskey 60 Farber Cat Lake Lake Union Verndale Johnson Wing River Lake Dog Lake

70 Aldrich Creek

Bluff Staples Benz Dower Lake Moran Lake River

Oak Stones 80 R. Tucker Creek Edwards Lake Hayden Lake Hewitt Lake TODD Jacobson Hayden Lake Munn Lake River COUNTY Lawrence South Bear Lake Lake Prairie Jasmer Partridge

90 Lake

Long Partridge

Creek S.

Base from U.S. Geological survey digital data 1:100,000, 1972 US Albers Equal Area Projection 0 5 10 MILES standard parallels 29°30' and 45°30', central meridian -95° 0 5 10 KILOMETERS

EXPLANATION

Cell with simulated ground-water withdrawals

Figure 11. Grid for finite-difference ground-water-flow model and model cells with simulated ground-water withdrawals, southern Wadena County and parts of surrounding counties, Minnesota. layer 1 and leakage through overlying layer 3 represents the amount of water surficial aquifer is present, the amount clay and till (confining units) to layer reaching the uppermost confined of leakage to the uppermost confined 3 in areas where the surficial aquifer aquifers by movement through the aquifers through the confining units is is absent. Areal recharge to layer 1 overlying confining units in areas computed by the model. represents the net difference between where the surficial aquifer is absent. Stream-aquifer leakage was simu- precipitation and surface runoff and Areal recharge or leakage was applied lated with head-dependent flux nodes evapotranspiration losses occurring to the highest active cell in each verti- (McDonald and Harbaugh, 1988, above the water table. Leakage to cal column of cells. In areas where the Chapter 6). The streams simulated

24 were the Crow Wing, Leaf, Long the model was 26.5 in./yr, which cor- tal hydraulic conductivity of 10 ft/d. Prairie, Red Eye, Wing, and Partridge responds to the estimated average Layer 2 was assigned a horizontal Rivers, South Bluff Creek, and Oak annual lake-evaporation rate in the hydraulic conductivity of 1.0 ft/d, Creek. The streams were divided into model area. The assumption was except for the area near the Leaf River reaches, each of which is completely made that evaporation from lakes was where only thin, discontinuous clay contained in a single cell. Stream- a reasonable estimate of the maximum layers are present. This area was aquifer leakage through a reach of ground-water evapotranspiration rate assigned a horizontal hydraulic con- streambed is dependent on: (1) the that occurs when the water table is at ductivity of 200 ft/d, the same as for vertical hydraulic conductivity, thick- the land surface. Evaporation from the uppermost confined aquifers. ness, and area (length times width) of lakes can be estimated from pan-evap- Layer 3 was assigned a horizontal the streambed; and (2) the difference oration data using a pan coefficient hydraulic conductivity of 150 ft/d in between stream stage and hydraulic (Baker and others,1979). The ground- areas where overlain by the upper- head in the aquifer. water evapotranspiration rate in the most confining units at land surface. The length of the streambed in model decreases linearly with depth The areas where the uppermost buried each river cell was measured on below land surface and becomes zero aquifers are absent were assigned a USGS 7.5-minute-quadrangle topo- at the extinction depth. The extinction horizontal hydraulic conductivity of graphic maps. The average widths of depth corresponds to a depth below 1.0 ft/d, representative of clay and till. the streambeds were estimated at land surface minimally greater than Initial values for vertical hydrau- stream-stage and discharge measure- the rooting depth of the plants present. lic conductivity for model layers 1 ment sites within the model area. The The plausible range for evapotranspi- and 3 were one-tenth the correspond- lower limit of the streambeds is ration extinction depth was assumed ing values for horizontal hydraulic poorly defined, thus the thickness of to be from 5 to 10 ft, based on plant conductivity. For layer 2, and for the streambeds was assumed to be 1 root-zone depths, with an average areas of layer 3 where the uppermost ft, which is similar to other numerical value of 7 ft. A root-zone depth of 5 ft confined aquifers are absent, an initial ground-water-flow models (Yager, was considered applicable by Helge- vertical hydraulic conductivity of 1993; Lindgren and Landon, 2000). sen (1977). The altitude of the land 0.001 ft/d was used. surface for each cell was determined The initial values for vertical hydrau- The initial values for areal lic conductivity of the streambeds from USGS 7.5-minute-quadrangle topographic maps. recharge were 9 in./yr for most of were: (1) 10 ft/d for the Leaf and Red layer 1 and 12 in./yr for the area near Eye Rivers; (2) 1.0 ft/d for the Crow The initial values of hydraulic the Leaf River, based on rates esti- Wing, Long Prairie, Wing, and Par- properties represented in the model mated for this investigation and those tridge Rivers; and (3) 0.1 ft/d for are listed in table 4. Initial values for reported by Lindholm (1970). The ini- South Bluff and Oak Creeks, based on hydraulic conductivity for each tial value for recharge to layer 3 by the observed texture of the riverbed hydrogeologic unit were based on the leakage through overlying till in areas material. Published values for vertical reported results of aquifer tests con- not overlain by the surficial aquifer hydraulic conductivity of riverbed ducted in the study area and published was 2 in./yr, based on reported values material for streams in glacial terrain values in the literature. Different hori- (table 2). commonly range from 0.1 to 10 ft/d zontal hydraulic conductivity values (Norris and Fidler, 1969; Jorgensen were assigned to each model layer and Numerical Model Calibration and Ackroyd, 1973; Prince and others, areally to zones of differing geologic Model calibration is a process in 1987; Delin, 1990; and Lindgren and materials based on well and test-hole which initial estimates of aquifer Landon, 2000). Stream stage for each logs. Layer 1 was divided into 3 hori- properties and boundary conditions river cell between measured stream- zontal hydraulic conductivity zones. are adjusted until simulated hydraulic stage sites was interpolated based on The western part was assigned a hori- heads and fluxes acceptably match the length of the stream reach in the zontal hydraulic conductivity 200 ft/d. measured water levels and fluxes. cell. The area near the Leaf River was Calibration and evaluation of the Discharge by ground-water assigned a horizontal hydraulic con- ground-water-flow model were con- evapotranspiration occurs from layer ductivity of 300 ft/d. The eastern area ducted for steady-state (equilibrium) 1. The model simulates evapotranspi- was assigned a horizontal hydraulic conditions and for transient condi- ration from the saturated zone only. conductivity of 150 ft/d, with smaller tions. No storage terms are included The initial maximum ground-water areas near the northern reach of the in the steady-state simulation. Tran- evapotranspiration rate specified in Crow Wing River assigned a horizon- sient simulations incorporate the stor-

25 95°15' 95°07'30" 95° 94°52'30" 94°45'

46°37'30" 6 Ck. 1 6 Sebeka 1 6 1 6 1 6 1 Red Beaver Creek Strike Lake T Granning 136 Lake Oylen N Eye Farnham

Creek

Crow Hay Creek 31 36 31 36 31 36 31 36 31 36 Creek Martin Creek Blue 6 1 6 1 6 1 6 Sand 1 6 1 River Lake Tower Sugar Creek Mud Creek Lake Little Farnham T 46°30' OTTER TAIL COUNTY Lake CASS 135 WADENA N Bluff River COUNTY COUNTY Leaf River Pulver Creek Creek Bluffton Leaf Lake

Creek 31 36 31 36 31 36 31 36 31 Iron 36 Ck. Radabaugh 6 1 6 1 1 6 1 1 Wadena 6 Lake6

River Ck. Rice Simon South

Lovejoy Lake Creek Creek Lake Lake Wing T

Whiskey Farber Cat 134 Lake Lake N Union Verndale Johnson Wing River Lake Dog Lake

31 36 31 31 Aldrich 46°22'30" 36 36 31 Creek 36 31 36 Bluff

6 6 Benz 1 1 1 6 1 6 Staples 1 6 Dower Lake Moran Lake River

Oak Stones R. Tucker Creek Edwards Lake Hayden Lake Hewitt Lake T TODD Hayden Lake Jacobson 133 Munn Lake River

COUNTY Lawrence N South

Bear ge Lake Lake Prairie Jasmer Partridge Lake

Long Partrid

Creek S. 31 36 31 36 31 36 31 36 31 36

R 36 W R 35 W R 34 W R 33 W R 32 W

Base from U.S. Geological survey digital data 1:100,000, 1972 0 5 10 MILES US Albers Equal Area Projection standard parallels 29°30' and 45°30', central meridian -95° 0 5 10 KILOMETERS

EXPLANATION

Inactive cells

Horizontal hydraulic conductivity of 5 feet per day

Horizontal hydraulic conductivity of 100 feet per day

Horizontal hydraulic conductivity of 150 feet per day

Horizontal hydraulic conductivity of 200 feet per day

Horizontal hydraulic conductivity of 350 feet per day

Figure 12a. Simulated boundary conditions and horizontal hydraulic conductivity zones for ground-water-flow model layer 1, southern Wadena County and parts of surrounding counties, Minnesota.

26 95°15' 95°07'30" 95° 94°52'30" 94°45'

46°37'30" 6 Ck. 1 6 Sebeka 1 6 1 6 1 6 1 Red Beaver Creek Strike Lake T Granning 136 Lake Oylen N Eye Farnham

Creek

Crow Hay Creek 31 36 31 36 31 36 31 36 31 36 Creek Martin Creek Blue 6 1 6 1 6 1 6 Sand 1 6 1 River Lake Tower Sugar Creek Mud Creek Lake Little Farnham T 46°30' OTTER TAIL WADENA COUNTY COUNTY Lake CASS 135 N Bluff River COUNTY Leaf River Pulver Creek Creek Bluffton Leaf Lake

Creek 31 36 31 36 31 36 31 36 31 Iron 36 Ck. Radabaugh 6 1 6 1 1 6 1 1 Wadena 6 Lake6

River Ck. Rice Simon South

Lovejoy Lake Creek Creek Lake Lake Wing T

Whiskey Farber Cat 134 Lake Lake N Union Verndale Johnson Wing River Lake Dog Lake

31 36 31 31 Aldrich 46°22'30" 36 36 31 Creek 36 31 36 Bluff

6 6 Benz 1 1 1 6 1 6 Staples 1 6 Dower Lake Moran Lake River

Oak Stones R. Tucker Creek Edwards Lake Hayden Lake Hewitt Lake T TODD Hayden Lake Jacobson 133 Munn Lake River COUNTY Lawrence N South Bear Lake Lake Prairie Jasmer Partridge Lake

Long Partridge

Creek S. 31 36 31 36 31 36 31 36 31 36

R 36 W R 35 W R 34 W R 33 W R 32 W

Base from U.S. Geological survey digital data 1:100,000, 1972 0 5 10 MILES US Albers Equal Area Projection standard parallels 29°30' and 45°30', central meridian -95° 0 5 10 KILOMETERS

EXPLANATION

Inactive cells

Horizontal and vertical hydraulic conductivities of 1 and 0.0025 feet per day, respectively

Horizontal and vertical hydraulic conductivities of 1 and 0.0075 feet per day, respectively

Horizontal and vertical hydraulic conductivities of 1 and 0.05 feet per day, respectively

Horizontal and vertical hydraulic conductivities of 1 and 0.1 feet per day, respectively

Horizontal and vertical hydraulic conductivities of 5 and 0.25 feet per day, respectively

Horizontal and vertical hydraulic conductivities of 200 and 20 feet per day, respectively

Figure 12b. Simulated boundary conditions and horizontal and vertical hydraulic conductivity zones for ground-water-flow model layer 2, southern Wadena County and parts of surrounding counties, Minnesota.

27 95°15' 95°07'30" 95° 94°52'30" 94°45'

46°37'30" 6 Ck. 1 6 Sebeka 1 6 1 6 1 6 1 Red Beaver Creek Strike Lake T Granning 136 Lake Oylen N Eye Farnham

Creek

Crow Hay Creek 31 36 31 36 31 36 31 36 31 36 Creek Martin Creek Blue 6 1 6 1 6 1 6 Sand 1 6 1 River Lake Tower Sugar Creek Mud Creek Lake Little Farnham T 46°30' OTTER TAIL WADENA COUNTY COUNTY Lake CASS 135 N Bluff River COUNTY Leaf River Pulver Creek Creek Bluffton Leaf Lake

Creek 31 36 31 36 31 36 31 36 31 Iron 36 Ck. Radabaugh 6 1 6 1 1 6 1 1 Wadena 6 Lake6

River Ck. Rice Simon South

Lovejoy Lake Creek Creek Lake Lake Wing T

Whiskey Farber Cat 134 Lake Lake N Union Verndale Johnson Wing River Lake Dog Lake

31 36 31 31 Aldrich 46°22'30" 36 36 31 Creek 36 31 36 Bluff

6 6 Benz 1 1 1 6 1 6 Staples 1 6 Dower Lake Moran Lake River

Oak Stones R. Tucker Creek Edwards Lake Hayden Lake Hewitt Lake T TODD Hayden Lake Jacobson 133 Munn Lake River

COUNTY Lawrence N South

Bear ge Lake Lake Prairie Jasmer Partridge Lake

Long Partrid

Creek S. 31 36 31 36 31 36 31 36 31 36

R 36 W R 35 W R 34 W R 33 W R 32 W

Base from U.S. Geological survey digital data 1:100,000, 1972 0 5 10 MILES US Albers Equal Area Projection standard parallels 29°30' and 45°30', central meridian -95° 0 5 10 KILOMETERS

EXPLANATION

Horizontal hydraulic conductivity of 1-5 feet per day

Horizontal hydraulic conductivity of 50 feet per day

Horizontal hydraulic conductivity of 100 feet per day

Horizontal hydraulic conductivity of 150 feet per day

Horizontal hydraulic conductivity of 200 feet per day

Horizontal hydraulic conductivity of 250 feet per day

Constant-head boundary cell

Figure 12c. Simulated boundary conditions and horizontal hydraulic conductivity zones for ground-water-flow model layer 3, southern Wadena County and parts of surrounding counties, Minnesota.

28 Table 4. Initial and final calibration values of hydraulic properties and fluxes simulated in numerical ground-water-flow model, southern Wadena County, and parts of surrounding counties, Minnesota [in./yr, inches per year; ft/d, feet per day; ft, feet] Hydraulic property for fluxes and hydrogeologic unit Inital value Final calibration Horizontal hydraulic conductivity (ft/d) Surficial aquifer (layer 1) Western area 200 200 Leaf River area 300 350 Eastern area 10, 150 5, 100, 150 Uppermost confining units (layer 2) Main body 1 1, 5 Discontinuous confining units area 200 200, 1 Uppermost confined aquifers (layer 3) Surficial aquifer present 150 150 Surficial aquifer absent 200 5 - 250 Uppermost confined aquifers absent 1 1, 5 Vertical hydraulic conductivity (ft/d) Surficial aquifer (layer 1) Western area 20 20 Leaf River area 30 35 Eastern area 1, 15 0.25, 0.01, 15 Uppermost confining units (layer 2) Main body 0.001 0.0025 - 0.25 Discontinuous confining units area 20 20 Uppermost confined aquifers (layer 3) Surficial aquifer present 15 15 Surficial aquifer absent 20 0.0005 - 25 Uppermost confined aquifers absent 0.001 0.0005 Specific yield for surficial aquifer 0.15 0.20 Storage coefficient Uppermost confining units (layer 2) 0.0001 0.0001 Uppermost confined aquifers (layer 3) 0.001 0.0005 - 0.025 Areal recharge to surficial aquifer (in./yr)(steady-state simulation) 6 7 Main body 9 10 Leaf River area 12 12 Recharge to uppermost confined aquifers by leakage where not overlain by surficial aquifer (in./yr) (steady-state simulation) (layer 3) Northwest area 2 1.6 South-central area 2 0.0, 0.9 Southwest area 2 0.9 Eastern areas 2 0.9 Uppermost confined aquifers absent areas 0 0 Ground-water evapotranspiration rate (in./yr) 26.5 26.5 Ground-water evapotranspiration extinction depth (ft) 7 5 age properties of the aquifers and are Steady-State Simulation stream-aquifer leakage) were used to time dependent. Changes in storage in calibrate the model under approxi- the aquifers occur when the amount of Water levels measured in 126 mate steady-state conditions. Aver- water entering the aquifers and the observation wells during December age ground-water withdrawals by amount of water leaving the aquifers 1998 and streamflows measured at high-capacity water-supply wells are not equal. 24–28 sites during August 1998 and from the surficial and uppermost con- November 1999 (used to estimate fined aquifers during 1997 and 1998

29 were simulated. Total annual ground- aquifer for which December 1998 reasonably simulates directions of water withdrawals from layer 1 and water-level data were available. The ground-water flow in the aquifers. layer 3 for the steady-state simulation largest difference between measured 3 Comparison of stream-aquifer were 6.45 and 6.95 ft /s, respectively. and simulated hydraulic heads was leakage estimated from measured The model was calibrated by varying 8.2 ft. The difference was less than streamflows during August 1998 and the simulated values of: (1) hydraulic 3.0 ft at 23 of the wells and less than November 1999 and simulated properties of the hydrogeologic units 1.0 ft at 13 of the wells. The final sim- stream-aquifer leakage was also used (horizontal and vertical hydraulic con- ulated hydraulic heads were within to evaluate how well the model simu- ductivity), (2) areal recharge to layer 5.0 ft of measured water levels at all lates the ground-water system (table 1 and leakage to layer 3 where layer 1 but 19 of the 86 wells completed in 1). Uncertainty of the stream-dis- is absent, (3) ground-water evapo- the uppermost confined aquifers for charge measurements was plus or transpiration rate and extinction which December 1998 water-level minus 5–8 percent. Estimates of depth, and (4) streambed vertical data were available. The largest dif- stream-aquifer leakage likely are less hydraulic conductivity. The final cali- ference between measured and simu- than the measurement uncertainty for bration values are listed in table 4 and lated hydraulic heads was 14.3 ft. The the measurements on the Crow Wing shown in figures 12 and 13. The difference was less than 3.0 ft at 39 of River; therefore the match between match between measured and simu- the wells and less than 1.0 ft at 23 of the measured and simulated stream- lated hydraulic heads and stream- the wells. The differences between aquifer leakage is uncertain. Esti- aquifer leakage was improved by: (1) simulated and measured hydraulic mates of stream-aquifer leakage, how- adjusting horizontal hydraulic con- heads at 2 wells completed in the ever, are greater than the ductivity values and zones (figs. 12a– uppermost confining units were less measurement uncertainty for the Leaf, 12c), (2) adjusting vertical hydraulic than 1.0 ft. Wing, Partridge, and Red Eye Rivers conductivity values and zones (fig. and comparisons between measured 12b), (3) increasing the areal recharge The mean absolute difference and simulated stream-aquifer leakage rate to most of layer 1 to 10 in./yr (fig. between simulated and measured can be made. For these streams, the 13, areal recharge zone 1), (4) hydraulic heads for the 126 wells, model reasonably represented the decreasing leakage rates to layer 3 computed as the sum of the absolute magnitude and direction of stream- where not overlain by the surficial values of the differences divided by aquifer leakage. For the Wing, Par- aquifer from 2 in./yr to 0 to 1.6 in./yr the number of wells, is 1.92 ft. The tridge, and Red Eye Rivers and two of (fig. 13, leakage zones 3–5), and (5) mean absolute difference between the four reaches of the Leaf River, the decreasing the ground-water evapo- simulated and measured hydraulic simulated stream-aquifer leakage was transpiration extinction depth to 5 ft heads at wells completed in the surfi- within the range of the measured (table 4). The above changes are con- cial and uppermost confined aquifers stream-aquifer leakage (table 1). For sidered acceptable because they are is 2.1 ft and 1.8 ft, respectively. The reach SW7-SW8 of the Leaf River, all within ranges of values measured mean algebraic difference between the simulated stream-aquifer leakage for this investigation or reported by simulated and measured hydraulic is less than the measured values, but is previous investigations (table 2). The heads for the 126 wells, computed as of the same order of magnitude (table initially uniform rate of simulated the algebraic sum of the differences 1). leakage to layer 3 where not overlain divided by the number of wells, is - A water budget is an accounting by the surficial aquifer (2 in./yr) did 0.13 ft, indicating the positive differ- not accurately simulate measured of inflow to, outflow from, and stor- ences were approximately balanced age change in the aquifers. For steady hydraulic heads in the aquifers. Dur- by the negative differences. The mean ing calibration, the leakage rates were state, inflow (sources) to the aquifers algebraic difference between simu- varied within reported ranges for dif- equals outflow (discharges) from the lated and measured hydraulic heads at ferent parts of the study area. The dis- aquifers (table 5). Areal recharge to wells completed in the surficial and tribution of leakage rates that best the surficial aquifer accounts for 86.9 uppermost confined aquifers is -0.6 ft matched measured hydraulic heads is percent of the water to the aquifers, and 0.2 ft, respectively. The simulated shown in figure 13. and leakage through the confining potentiometric surfaces for the surfi- units to the uppermost confined aqui- The final simulated steady-state cial and uppermost confined aquifers, fers where the surficial aquifer is hydraulic heads were within 5.5 ft of shown in figures 14a and 14b, respec- absent contributes 6.9 percent (table measured water levels at all but 7 of tively, are consistent with the mea- 5). The remaining 6.2 percent is by the 38 wells completed in the surficial sured water levels and the model flow into the uppermost confined

30 95°15' 95°07'30" 95° 94°52'30" 94°45'

46°37'30" 6 Ck. 1 6 Sebeka 1 6 1 6 1 6 1 Red Beaver Creek 3 Strike Lake 3 T Granning 4 136 Lake Oylen N Eye 1 Farnham 5 Creek

Crow Hay Creek 31 36 31 36 31 36 31 36 31 36 Creek Martin Creek Blue 6 1 6 1 6 1 6 Sand 1 6 1 River Lake Tower 5 Sugar Creek Mud Creek Lake Little Farnham T 46°30' OTTER TAIL WADENA COUNTY COUNTY Lake CASS 135 N Bluff River COUNTY Leaf 2 River Pulver Creek Creek Bluffton Leaf Lake

Creek 31 36 31 36 31 36 31 36 31 Iron 36 Ck. Radabaugh 6 1 6 1 1 6 1 1 4 Wadena 6 Lake6

River Ck. 1 Rice Simon South

Lovejoy Lake Creek Creek Lake Lake Wing T

Whiskey Farber Cat 134 Lake Lake Verndale N 1 Union Johnson Wing River Lake 4 Dog Lake

31 36 31 31 Aldrich 46°22'30" 36 36 31 Creek 36 31 36 Bluff

6 6 Benz 1 1 1 6 1 6 Staples 1 6 Dower Lake Moran Lake River

Oak Stones R. Tucker Creek Edwards Lake Hayden Lake Hewitt Lake 1 T TODD 3 Hayden Lake Jacobson 133 Munn Lake River

COUNTY Lawrence N South

4 Bear ge Lake Lake Prairie Jasmer Partridge Lake

Long Partrid Creek 5 S. 31 36 31 36 31 36 31 36 31 36

R 36 W R 35 W R 34 W R 33 W R 32 W

Base from U.S. Geological survey digital data 1:100,000, 1972 0 5 10 MILES US Albers Equal Area Projection standard parallels 29°30' and 45°30', central meridian -95° 0 5 10 KILOMETERS

EXPLANATION

Simulated areal recharge zones

1 Areal recharge to model layer 1 (surficial aquifer) equals 10 inches per year 2 Areal recharge to model layer 1 (surficial aquifer) equal 12 inches per year

Simulated leakage zones

3 Leakage through till to model layer 3 (uppermost confined aquifer) equals 0.0 inches per year 4 Leakage through till to model layer 3 (uppermost confined aquifer) equals 0.9 inches per year 5 Leakage through till to model layer 3 (uppermost confined aquifer) equals 1.6 inches per year

Figure 13. Simulated areal recharge and leakage zones for ground-water-flow model, southern Wadena County and parts of surrounding counties, Minnesota.

31 95°15' 95°07'30" 95° 1341 94°52'30" 94°45'

46°37'30" 6 Ck. 1 6 Sebeka 1 6 1 6 1 6 1 Red 1300 Beaver Creek Strike 1330 Lake T 1323 Granning 136 Lake Oylen N Eye Farnham 1320 1280 Creek

Crow Hay Creek 31 36 31 36 31 36 31 129336 31 36 Creek 1300 Martin Creek Blue 1310 6 1 6 1 6 1 13076 1289 Sand 1 6 1 River Lake Tower 1300 Sugar Creek Mud Creek 1288 1290 1252 Lake 1289 Little 1280 Farnham T 46°30' OTTER TAIL WADENA 1270 1255 Lake 135 COUNTY COUNTY 1270 CASS 1281 1262 N Bluff River 1265 COUNTY Leaf 1299 River Pulver Creek Creek Bluffton Leaf Lake 1290 1271 1256 Creek 31 1260 36 31 36 31 31 1300 36 124436 31 Iron 36 Ck. 1310 Radabaugh

6 1 6 6 1256 1 1250

1344 1 1 1250 1

Wadena 1320 6 Lake6

1260

1280 1280 1270 1330 1317 River Ck. Rice 1343 1340 Simon South

Lovejoy Lake Creek Creek Lake Lake Wing T Whiskey 1350 1235 Farber Cat 134 1332 1329 1240 Lake Lake N Union Verndale Johnson 1360 Wing River Lake 1336 1325 1285 1267 Dog 1370 1230 Lake

31 36 31 31 Aldrich 46°22'30" 36 36 31 Creek 36 31 36 Bluff 1380 1231 1241 6 6 Benz 1 1 1350 1 6 1 6 Staples 1 6 Dower 1240Lake 1390 Moran Lake River 1230

Oak 1382 Stones R. Tucker Creek Edwards 1400 Lake Hayden Lake 1220 Hewitt Lake T TODD Hayden 1250Lake 1234 Jacobson 133 Munn Lake River COUNTY Lawrence N South 1404 Bear Lake Lake Prairie 1410 Jasmer 1415 Partridge Lake 1255 Long Partridge 1260 Creek 1420 S. 31 1430 36 31 36 1240 31 36 31 36 31 36

R 36 W R 35 W R 34 W R 33 W R 32 W Base from U.S. Geological survey digital data 1:100,000, 1972 0 5 10 MILES US Albers Equal Area Projection standard parallels 29°30' and 45°30', central meridian -95° 0 5 10 KILOMETERS

EXPLANATION

Extent of surficial aquifer

Area where surficial aquifer is absent

1360 Simulated potentiometric contour--Interval 10 feet. Datum is sea level 1325 Observation well completed in surficial aquifer--Number is measured water-level altitude

Figure 14a. Measured water-level altitude in the surficial aquifer, December 1998, simulated altitude of potentiometric surface for model layer 1, steady-state conditions, and extent of surficial aquifer, southern Wadena County and parts of surrounding counties, Minnesota.

32 95°15' 95°07'30" 95° 94°52'30" 94°45'

46°37'30" 6 Ck. 1 6 Sebeka 1 6 1 6 13261 6 1 Red 1323 Beaver 1356 Creek 1423 1329 1326 Strike 1340 1325 Lake 1437 1326 T Granning 1330 136 Lake N 1430 1430 1323 Oylen 1420 Eye 1410 Farnham1320 1400 1390 1355 1439 1380 1417 1283 1310 1370 Creek 1300

1360 Crow Hay 1290 Creek 31 36 31 1350 1387 36 31 1313 36 31 36 31 36 Creek 1340 1302 Martin 1326 Creek Blue 1 6 1330 6 1404 1 6 6 1307 1343 1320 1 1289 Sand 1 6 1302 1 River Lake Tower 1393 1373 1310 Sugar Creek Mud Creek 13001293 Lake Little 1295 1290 Farnham T 46°30' OTTER TAIL WADENA 1306 1297 1258 Lake COUNTY COUNTY CASS 135 1303 N 1373 1281 1280 1262 Bluff River 1265 COUNTY Leaf River Pulver Creek 1322 Creek Bluffton Leaf 1299 1281 Lake 1320 1301 Creek 31 36 31 1337 36 31 1291 36 31 1245 36 31 Iron 36 Ck. 1330 1300 1303 Radabaugh 6 1 6 1311 6 1 1 1300 1 6 1286 1 Lake 1318 1342 Wadena 6 1326 1310 1303 River 1338 Ck. Rice 1270 1260 1260 1250 Simon South

1320 1280 1280 Lovejoy Lake Creek Creek 1345 1290 Lake 1330 Lake Wing T Whiskey 1235 1231 Farber Cat 134 1349 1327 1329 Lake Lake 1352 Verndale 1309 1282 N Union 1247 Johnson 1340 Wing River Lake

1340 1287 Dog 1350

1372 1350 1296 1293 1268 Lake

1360 31 36 31 1338 31 Aldrich 46°22'30" 1376 36 36 31 Creek 36 124431 36 Bluff 1370 1344 1241 1235

6 1 6 Staples Benz 1 1380 1 6 1 6 1 61242 Dower Lake 1220 Moran 1220 Lake River 1390

Oak Stones R. Tucker Creek Edwards

Lake 1263 Hayden Lake 1230

Hewitt 1357 Lake 1230 T 1400 TODD Hayden Lake

Jacobson 133 1240 Munn Lake 1240 River COUNTY Lawrence N South Bear 1321 Lake 1234 Lake Prairie 1416 Jasmer 1410 Partridge 1406 1279 Lake Long 1420 Partridge 1326 Creek S. 31 36 31 36 1430 1383 31 36 31 36 31 36

R 36 W R 35 W R 34 W R 33 W R 32 W 0 5 10 MILES Base from U.S. Geological survey digital data 1:100,000, 1972 US Albers Equal Area Projection 0 5 10 KILOMETERS standard parallels 29°30' and 45°30', central meridian -95°

EXPLANATION 1380 Simulated potentiometric contour--Interval 10 feet. Datum is sea level 1329 Observation well completed in uppermost confined aquifer--Number is measured water-level altitude

Figure 14b. Measured water-level altitude in the uppermost confined aquifers, December 1998, and simulated altitude of potentiometric surface for model layer 3, steady-state conditions, southern Wadena County and parts of surrounding counties, Minnesota.

33 aquifers at the study area boundaries (41.4 percent) (table 5). Net discharge upward directions. The model simula- (constant-head boundaries) (5.0 per- from the aquifer to streams of 179.41 tion indicates a net flow upward of cent) and by leakage from streams ft3/s represents 54.5 percent of the 32.16 ft3/s from layer 3 to layer 1 into the surficial aquifer (1.2 percent). areal recharge to the surficial aquifer. through layer 2 (table 5). This net Most of the flow into the uppermost Pumpage constitutes 4.1 percent of flow upward is balanced by leakage confined aquifers at the study area the discharges from the aquifers, with and flow through constant-head boundaries occurs through the south- the withdrawals being approximately boundaries to layer 3. western boundary (61.2 percent), with equally divided between the surficial The calibration steady-state simu- minimal flow through the northwest- (layer 1) and uppermost confined lation is considered to be reasonable ern boundary. aquifers (layer 3). because: (1) hydraulic conductivity The largest discharges from the Water flows vertically through the values of the aquifers are known aquifers are leakage from the surficial uppermost confining units separating within a relatively small range of aquifer to streams (54.5 percent) and the surficial and uppermost confined measured or reported values; (2) rea- ground-water evapotranspiration aquifers in both downward and sonable estimates of the major dis-

Table 5. Simulated water budget for the steady-state model, southern Wadena County and parts of surrounding counties, Minnesota [Numbers in parentheses are percentages of total sources or of total discharges; --, not applicable]

Discharge Budget component Source (cubic feet per second) (cubic feet per second) Areal recharge to surficial aquifer (layer 1) 285.96 (86.9) -- Leakage through confining units to uppermost confined aquifers 22.75 (6.9) -- where surficial aquifer is absent (layer 3) Flow into uppermost confined aquifers at study area boundaries (constant-head boundaries) (layer 3) Southwestern boundary 10.04 (3.1) -- Northeastern boundary 6.31 (1.9) -- Northwestern boundary 0.05 (0.0) -- Subtotal 16.4 (5.0) -- Leakage from streams to surficial aquifer (layer 1) 4.04 (1.2) -- Pumpage Layer 1 -- 6.45 (2.0) Layer 3 -- 6.95 (2.1) Subtotal -- 13.4 (4.1) Ground-water evapotranspiration (layer 1) -- 136.34 (41.4) Leakage from surficial aquifer to streams (layer 1) -- 179.41 (54.5) Total 329.15 (100.0) 329.15 (100.0) Leakage between model layers Layer 1 102.27 69.85 Layer 2 Layer 1 69.85 102.27 Layer 3 95.77 63.61 Subtotal 165.62 165.88 Layer 3 63.61 95.77 Total 331.50 331.50

34 charges from the aquifers in the study transient simulation were the simu- of seasonal ground-water evapotrans- area–ground-water discharge to lated hydraulic heads from the cali- piration rates than pan-evapotranspi- streams and ground-water withdraw- bration steady-state simulation. ration rates alone. The maximum als by wells–are available; and (3) the The initial values for simulated ground-water evapotranspiration rates simulation results reasonably repre- areal recharge rates to layer 1 and were calculated as the reported pan- sented the correct magnitude and leakage to layer 3 for each stress evaporation rate at Staples during a direction of leakage between the period are shown in table 6. The ini- stress period, multiplied by 0.3 for the streams and the surficial aquifer. tial values for areal recharge for each early summer stress periods or by 0.8 Transient Simulation stress period were derived to account for the late summer stress periods. The model was calibrated under for spring snowmelt and seasonal In addition to areal recharge and transient conditions using seasonally ground-water evapotranspiration ground-water evapotranspiration, sea- variable ground-water withdrawals, rates. Areal recharge rates for the sonal variations in the constant heads areal recharge and leakage rates, spring, early summer, and fall 1998 specified at the model boundaries and ground-water evapotranspiration stress periods were calculated as the in stream stages were simulated. The rates, and stream stages and the result- product of the average water-level seasonal variations in the constant ing fluctuations in hydraulic heads in rises in observation wells during the heads were derived from the hydraulic the aquifers during December 1997 respective stress periods and a spe- heads measured in the same observa- through November 1999. Reported cific yield of 0.20. Areal recharge tion wells used for the steady-state monthly ground-water withdrawals by rates for the winter, late summer, and simulation. Seasonal variations in high-capacity wells within the model fall 1999 stress periods were assigned stream stages were derived from area were used in the transient simula- a value of zero to reflect no net areal monthly stage measurements at 11 tion. Hydraulic conductivity values recharge to ground water, as indicated sites during the investigation. for the hydrogeologic units were the by most hydrographs. The initial val- The model was calibrated to tran- same as for the steady-state simula- ues for leakage to layer 3 were sient conditions by adjusting specific tion (table 4). The initial value of spe- assigned to each stress period based yield, storage coefficient values, cific yield for layer 1 was 0.15, based on the distribution of assigned areal stress-period areal recharge, and on an aquifer test previously con- recharge rates for the stress periods stress period ground-water evapo- ducted in the study area (Lindholm, (table 6). Leakage rates for the winter, transpiration rates until the simulated 1970). The initial storage coefficient late summer, and fall 1999 stress peri- hydraulic heads acceptably matched specified for layer 3 was 0.001, based ods were assigned a value of zero, water levels measured in wells during on aquifer tests previously conducted with the highest leakage rate being December 1997 through November in the study area (Lindholm, 1970) assigned to the early summer stress 1999. Monthly water-level measure- (table 4). The initial value of storage periods. ments were available for 81 observa- coefficient assigned to layer 2 was Ground-water evapotranspiration tion wells during December 1997 0.0001, based on recorded values in rates also vary seasonally (table 6). through November 1999. The match the literature (table 4). The initial values for maximum between simulated and measured To simulate transient conditions ground-water evapotranspiration hydraulic heads was improved by: (1) during December 1997 through rates, by stress period, were based on increasing the specific yield of layer 1 November 1999, five stress periods seasonal ratios of evapotranspiration from 0.15 to 0.20, (2) decreasing the were specified each year. The stress to pan evaporation published by the storage coefficient in the southwest- periods specified were winter Southwest Agricultural Experiment ern part of layer 3, and (3) increasing (December-February), spring (March- Station, University of Minnesota, in the storage coefficient in the central April), early summer (May-June), late southwestern Minnesota (Baker and part of layer 3 (table 4, fig. 15). The summer (July-September), and fall others, 1979). The seasonal ratios match was also improved by: (1) (October-November). Simulated incorporate: (1) differences between increasing areal recharge to layer 1 for ground-water withdrawals during the pan (used to measure pan evapora- recharge zone 2 during the spring, 1999 for the specified stress periods tion) and soil and plants, and how early summer, and fall 1998 stress ranged from 1.59 ft3/s for winter to much solar energy they absorb; and periods, (2) decreasing leakage to 29.55 ft3/s for late summer. The with- (2) variations in available soil water. layer 3 for recharge zone 4 during the drawal rates for each stress period The ratio varies from about 0.15 in the spring, early summer, and fall 1998 during 1998 were similar to the 1999 spring and fall to about 0.90 in July stress periods, (3) decreasing leakage rates. The starting heads used in the and provides a more accurate estimate to layer 3 for recharge zone 5 during

35 Table 6. Initial and final calibration values of areal recharge, leakage, and ground-water evapotranspiration for transient simulation, southern Wadena County and parts of surrounding counties, Minnesota [All values in inches per year]

Maximum ground-water Recharge evapotranspiration Leakage through confining unit to uppermost confined aquifers where Areal recharge to surficial aquifer surficial aquifer is absent Zone 1 Zone 2 Zone 3 Zone 4 Zone 5 Final Final Final Final Final Final Initial Initial Initial Initial Initial Initial Stress period calibration calibration calibration calibration calibration calibration value value value value value value value value value value value value Winter 1998 0 0 0 0 0 0 0 0 0 0 0 0 Spring 1998 26.9 26.9 26.9 35.9 0 0 4.8 1.8 4.8 3.5 0 0 Early summer 1998 35.9 35.9 35.9 47.9 0 0 6.4 3.6 6.4 5.5 27.7 27.7 Late summer 1998 0 0 0 0 0 0 0 0 0 0 69.6 78.3 Fall 1998 18.0 18.0 18.0 26.9 0 0 3.0 0.9 3.0 3.0 0 0

36 Winter 1999 0 0 0 0 0 0 0 0 0 0 0 0 Spring 1999 26.9 26.9 26.9 35.9 0 0 4.8 3.6 4.8 3.5 0 0 Early summer 1999 35.9 35.9 35.9 47.9 0 0 6.4 3.6 6.4 5.5 26.0 26.0 Late summer 1999 0 0 0 0 0 0 0 0 0 0 59.3 66.7 Fall 1999 0 0 0 0 0 0 0 0 0 0 0 0 the spring and early summer stress stress periods because no areal The net stream-aquifer leakage periods, and (4) increasing the recharge or leakage occurs to the during each stress period in 1999 was ground-water evapotranspiration rate aquifers. The effects of ground-water from the surficial aquifer to the during the late summer stress period withdrawals, ground-water evapo- streams for the model area as a whole (table 6). transpiration (late summer stress (table 7). The net gains to streams The transient simulation for period), and stream-aquifer leakage during the winter, late summer, and December 1997 through November are, therefore, magnified during these fall stress periods are similar, but the 1999 acceptably reproduces measured stress periods. The water released gains during the spring and early sum- seasonal fluctuations in hydraulic from storage is derived predominantly mer stress periods are much greater heads in the surficial and uppermost from the surficial aquifer (from 68.4 than during the other stress periods. confined aquifers (fig. 9). The ability to 77.2 percent). From 21.9 to 30.7 The stress periods with large gains to of the transient simulation to approxi- percent of the water released from streams correspond with the stress mate seasonal fluctuations in hydrau- storage is derived from the uppermost periods when areal recharge occurs. lic heads during December 1997 confined aquifers. During stress peri- These results indicate that the magni- through November 1999 indicates that ods with areal recharge, a greater pro- tude of simulated gains to streams is the simulation reasonably represents portion of the water withdrawn by in direct relation to the amount of hydraulic properties of the hydrogeo- wells is supplied by the areal recharge areal recharge. logic units and fluxes in the ground- and less release of water from storage EFFECTS OF GROUND-WATER is required. water system during the calibration WITHDRAWALS period. The specified boundary condi- The principal discharges from the tions are considered appropriate, areal The ground-water flow model aquifers are: (1) leakage from the was used as a tool to evaluate ground- recharge and leakage to the aquifers surficial aquifer to streams during the are within reasonable expected water availability in the study area by fall and winter stress periods, (2) assessing the potential effects of ranges, and ground-water withdrawals addition to storage during the spring are known. Table 4 gives the values hypothetical conditions on ground- and early summer stress periods, and water levels and streamflow. The for the hydraulic properties of the (3) ground-water evapotranspiration hydrogeologic units resulting in the hypothetical simulations test the during the late summer stress period effects of: (1) historical withdrawals, best fit between measured and simu- (table 7). Ground-water withdrawals lated hydraulic heads for the transient (2) anticipated increases in ground- are greatest during the early summer water withdrawals (pumping), (3) simulation. The values given repre- and late summer stress periods, con- sent the best estimates for the hydrau- anticipated increases in withdrawals stituting 1.6 and 5.6 percent of the during a drought, (4) greater than lic properties of the hydrogeologic total discharges, respectively, during units in the study area, based on anticipated increases in withdrawals, these stress periods. Areal recharge and (5) greater than anticipated reported values and the results of the and leakage to the uppermost con- model calibration. increases in withdrawals during a fined aquifers is greater than the sum drought. Table 8 is a summary of the The simulated transient water of the discharges from the aquifers hypothetical steady-state model simu- budget for 1999 is shown in table 7. (other than addition to storage) during lations and corresponding responses. Principal sources of water to the aqui- the spring and early summer stress Steady-state simulations represent fers were areal recharge to the surfi- periods. A portion of the areal average, equilibrium conditions and cial aquifer during the spring and recharge and leakage to the uppermost no times are associated with the early summer stress periods and confined aquifers is therefore returned responses. Two-year transient simula- release from storage during the win- to storage in the aquifers. The amount tions also were done for some of the ter, late summer, and fall stress peri- and percentage of addition to storage hypothetical conditions. ods. Areal recharge to the surficial during the spring and early summer aquifer dominates the water budget stress periods is much greater than Historical Withdrawals during the spring and early summer during the other stress periods Simulation 1 (table 8) was stress periods, constituting 87.6 and because areal recharge and leakage to designed to evaluate the effects of his- 93.1 percent of the sources of water the uppermost confined aquifers torical withdrawals on water levels for these stress periods, respectively. occurs during these stress periods. and streamflow. This was achieved by The amount and percentage of water Approximately 73 percent of the addi- removing pumping from the steady- released from storage is greatest dur- tion to storage occurs in the surficial state simulation and simulating aver- ing the winter, late summer, and fall aquifer. age recharge; results thus were pre-

37 95°15' 95°07'30" 95° 94°52'30" 94°45'

46°37'30" 6 Ck. 1 6 Sebeka 1 6 1 6 1 6 1 Red Beaver Creek Strike Lake T Granning 136 Lake Oylen N Eye Farnham

Creek

Crow Hay Creek 31 36 31 36 31 36 31 36 31 36 Creek Martin Creek Blue 6 1 6 1 6 1 6 Sand 1 6 1 River Lake Tower Sugar Creek Mud Creek Lake Little Farnham T 46°30' OTTER TAIL WADENA COUNTY COUNTY Lake CASS 135 N Bluff River COUNTY Leaf River Pulver Creek Creek Bluffton Leaf Lake

Creek 31 36 31 36 31 36 31 36 31 Iron 36 Ck. Radabaugh 6 1 6 1 1 6 1 1 Wadena 6 Lake6

River Ck. Rice Simon South

Lovejoy Lake Creek Creek Lake Lake Wing T

Whiskey Farber Cat 134 Lake Lake N Union Verndale Johnson Wing River Lake Dog Lake

31 36 31 31 Aldrich 46°22'30" 36 36 31 Creek 36 31 36 Bluff

6 6 Benz 1 1 1 6 1 6 Staples 1 6 Dower Lake Moran Lake River

Oak Stones R. Tucker Creek Edwards Lake Hayden Lake Hewitt Lake T TODD Hayden Lake Jacobson 133 Munn Lake River COUNTY Lawrence N South Bear Lake Lake Prairie Jasmer Partridge Lake

Long Partridge

Creek S. 31 36 31 36 31 36 31 36 31 36

R 36 W R 35 W R 34 W R 33 W R 32 W

Base from U.S. Geological survey digital data 1:100,000, 1972 0 5 10 MILES US Albers Equal Area Projection standard parallels 29°30' and 45°30', central meridian -95° 0 5 10 KILOMETERS

EXPLANATION

Storage coefficient of 0.025

Storage coefficient of 0.0025

Storage coefficient of 0.001

Storage coefficient of 0.0005

Figure 15. Storage coefficient zones for ground-water-flow model layer 3, southern Wadena County and parts of surrounding counties, Minnesota.

38 Table 7. Simulated water budget, by stress period, for 1999 for transient simulation, southern Wadena County and parts of surrounding counties, Minnesota [Numbers in parentheses are percentages of total sources or of total dischargesby stress period]

Sources of water by stress period (cubic feet per second) Winter Spring (March- Early summer Late summer Fall (October- Budget component (December- April) (May-June) (July-September) November) February) Recharge (from precipitation) to surficial 0 774.12 (87.6) 1033.07 (93.1) 0 0 aquifer (layer 1) Leakage through confining unit to upper- 0 93.00 (10.5) 65.67 (5.9) 0 0 most confined aquifers (layer 3) Flow into uppermost confined aquifers at study area boundaries (constant-head) 15.40 (8.4) 16.55 (1.9) 6.15 (0.6) 16.58 (3.1) 13.84 (6.4) (layer 3) Leakage from streams to surficial aquifer 0.54 (0.3) 0.15 (0.0) 0 7.92 (1.5) 0.33 (0.2) (layer 1) Release from storage Layer 1 120.44 (65.8) 0 3.79 (0.35) 389.89 (73.7) 138.19 (63.9) Layer 2 1.48 (0.8) 0 0.02 (0.0) 4.15 (0.8) 1.82 (0.8) Layer 3 45.33 (24.7) 0.02 (0.0) 0.56 (0.05) 110.81 (20.9) 62.12 (28.7) Subtotal 167.25 (91.3) 0.02 (0.0) 4.37 (0.4) 504.85 (95.4) 202.13 (93.4) Total 183.19 (100.0) 883.84 (100.0) 1109.26 (100.0) 529.35 (100.0) 216.30 (100.0) Discharges of water, by stress period (cubic feet per second) Pumpage Layer 1 0.11 (0.1) 0.11 (0.0) 9.19 (0.8) 17.26 (3.3) 0.14 (0.1) Layer 3 1.48 (0.8) 1.64 (0.2) 8.63 (0.8) 12.29 (2.3) 1.58 (0.7) Subtotal 1.59 (0.9) 1.75 (0.2) 17.82 (1.6) 29.55 (5.6) 1.72 (0.8) Ground water evapotranspiration (layer 1) 0 0 247.88 (22.3) 349.32 (66.0) 0 Flow out of uppermost confined aquifers at study area boundaries (constant-head 0 0 1.32 (0.1) 0.53 (0.1) 0.18 (0.1) boundaries) (layer 3) Leakage from surficial aquifers to streams 164.41 (89.7) 242.67 (27.5) 294.61 (26.6) 149.33 (28.2) 186.91 (86.4) (layer 1) Addition to storage Layer 1 13.91 (7.6) 465.97 (52.7) 398.71 (35.95) 0 24.01 (11.1) Layer 2 0.08 (0.05) 4.97 (0.55) 4.88 (0.45) 0.00 0.12 (0.1) Layer 3 3.2 (1.75) 168.49 (19.05) 143.97 (13.0) 0.63 (0.1) 3.35 (1.5) Subtotal 17.19 (9.4) 639.43 (72.3) 547.56 (49.4) 0.63 (0.1) 27.48 (12.7) Total 183.19 (100.0) 883.85 (100.0) 1109.19 (100.0) 529.36 (100.0) 216.29 (100.0) Difference: sources - discharges 0.00 -0.01 0.07 -0.01 0.01

39 sumed to approximate predevelop- occurred in the aquifer system since capacity wells. Model results also ment conditions. By comparing about 1970. indicate that ground-water discharge results of Simulation 1 with the to rivers has been reduced by less than Model results indicate that histor- steady-state (1998-99) calibration, one percent compared to predevelop- ical withdrawals have lowered water ment conditions. effects of historical withdrawals can levels regionally in the surficial and be estimated. A majority of ground- uppermost confined aquifers an aver- Anticipated Increases in water pumpage in the area is from age of 0.31 and 0.42 ft, respectively Withdrawals irrigation wells that were installed (figs. 16a and 16b). Declines in the Simulation 2 (table 8) was after about 1970. Prior to this time the surficial aquifer have been greatest designed to evaluate the steady-state only appreciable ground water pump- near Wadena (4.0 ft) and Staples (2.5 effects of anticipated increases in age was from a relatively few munici- ft). Maximum declines in the upper- withdrawals on water levels and pal, industrial, and commercial wells. most confined aquifers in Wadena and streamflow. Ground-water withdraw- Consequently, Simulation 1 is Staples have been 4.0 and 4.5 ft, als for irrigation in southern Wadena designed to estimate water level and respectively, and as much as 4.5 ft County are expected to increase by 20 streamflow changes that have elsewhere in the vicinity of other high percent over the next 10 to 20 years

Table 8. Summary of steady-state results of hypothetical model Simulations 1-5, southern Wadena County and parts of surrounding counties, Minnesota. [Increased withdrawal rates are in comparison to 1998-99 steady-state calibration rates; ET, evapotranspiration]

Simulation Conditions of simulation Model results Historical withdrawals Pumping removed to determine the Water levels decline an average of 0.31 ft in the surficial aquifer effects of historical pumpage Average precipitation. and 0.42 ft in the uppermost confined aquifers. Declines are 1 greatest (4.0 ft or greater) near Wadena and Staples in both aquifers. Ground-water discharge to streams is reduced less than one percent since predevelopment. Anticipated increases in withdrawals (20 percent increase for Water levels decline an average of 0.03 ft in the surficial aquifer 88 irrigation wells and 40 percent increase for 5 Wadena and 0.08 ft in the uppermost confined aquifers. Maximum municipal wells in uppermost confined aquifers). Average declines of 0.3 ft in the surficial aquifer and 0.9 ft in the upper- 2 recharge. most confined aquifers occur near Wadena. Ground-water discharge to streams is reduced by 0.6 percent of 1998-99 conditions. Anticipated increases in withdrawals with drought conditions Water levels decline an average of 2.13 ft in the surficial aquifer (33 percent increase for 160 irrigation, commercial, and dug- and 5.87 ft in the uppermost confined aquifers. Declines in the pit wells in the surficial aquifer; 53 percent for 88 irrigation surficial aquifer of about 6 ft occur in Wadena and between the wells, 50 percent for 5 Wadena municipal wells; and 10 per- Leaf, Red Eye, and Partridge Rivers. Declines in the uppermost 3 cent for other municipal wells in uppermost confined aqui- confined aquifers are similar to those in the surficial aquifer in fers). Average recharge reduced by 25 percent. ET rates general, but exceed 20 ft north of the Leaf River. Ground water increased 17 percent. Stream stage lowered 1.0 ft. Boundary discharge to streams is reduced by 23 percent of 1998-99 condi- heads lowered 3.0 ft. tions. Greater than anticipated increases in withdrawals (20 percent Water levels decline an average of 0.09 ft in the surficial aquifer increase for 160 irrigation, commercial, and dug-pit wells in and 0.13 ft in the uppermost confined aquifers. Ground-water 4 the surficial aquifer; 50 percent for 88 irrigation wells; and 40 discharge to streams is reduced by 1.4 percent of 1998-99 condi- percent for 5 Wadena municipal wells in uppermost confined tions. aquifers). Average recharge. Greater than anticipated increases in withdrawals with Water levels decline an average of 2.25 and 6 ft in the surficial drought conditions (53 percent increase for 160 irrigation, and uppermost confined aquifers, respectively. Ground-water commercial, and dug-pit wells in the surficial aquifer; 83 per- discharge to streams is reduced by 25 percent of 1998-99 condi- cent for 88 irrigation wells; and 50 percent for 5 Wadena tions. 5 municipal wells in uppermost confined aquifers). Average recharge reduced by 25 percent. ET rates increased 17 percent. Stream stage lowered 1 foot. Boundary heads lowered 3 ft.

40 (Malinda Dexter, Wadena Soil and that water levels will be minimally reduction in recharge used in Simula- Water Conservation District, oral affected by the anticipated increases tion 3 corresponds to 20 in. of annual commun., 2000). The increased within pumping. The maximum increase precipitation. A drought of this sever- drawals are all expected to be from in seasonal water-level decline for the ity has occurred during 8 years since wells completed in the uppermost uppermost confined aquifers would be 1905 (U.S. Department of Commerce, confined aquifers and in areas of 1.34 ft. 1999). existing irrigation development (Don Anticipated Increases in Results of the steady-state simula- Sirucek, Minnesota Department of tion indicate that the anticipated Agriculture, oral commun., 2000). Withdrawals During a Drought increases in withdrawals during a Ground-water withdrawals for munic- Simulation 3 (table 8) was drought may lower water levels 2 to 4 ipal supplies for Wadena are expected designed to evaluate the steady-state ft regionally in much of both the surfi- to increase by a maximum of 2 per- effects of anticipated increases in cial and uppermost confined aquifers cent per year (Gary Peters, City of withdrawals on water levels and (figs. 17a and 17b). Water-level Wadena, oral commun., 2000). streamflow during a typical drought. declines in the surficial aquifer of These anticipated increases were The drought was simulated by making about 6 ft may occur in Wadena and in simulated with the model by increas- the following changes to the model the central part of the aquifer south of ing withdrawals from the 88 irrigation compared to the 1998-99 steady-state the Leaf River (fig. 17a). Simulated wells completed in the uppermost rates: (1) increasing withdrawals from declines in the uppermost confined confined aquifers by 20 percent above the 113 irrigation and commercial aquifers for much of T133N, R35W 1998-99 withdrawals. Withdrawals wells and 47 dug pits in the surficial range from 6 to 8 ft due to withdraw- from the five Wadena municipal wells aquifer by 33 percent, (2) increasing als from irrigation wells (fig. 17b). completed in the uppermost confined irrigation well withdrawals from the Declines in the uppermost confined aquifers were also increased by 40 uppermost confined aquifers by 53 aquifers north of the Leaf River may percent. Average steady-state percent, (3) increasing withdrawals be 15 to 30 ft due to the compara- recharge conditions were simulated. from the 5 Wadena municipal wells in tively low hydraulic conductivities of A transient simulation was also used these aquifers and low recharge rates the uppermost confined aquifers by 50 to investigate the effects of the antici- through the overlying confining units. percent, (4) increasing withdrawals pated increases in withdrawals over a Simulated declines in all aquifers as a from the other municipal wells in the hypothetical 2-year period. Changes result of the anticipated increased uppermost confined aquifers by 10 made to the transient simulation withdrawals and hypothetical drought percent, (5) increasing maximum inputs were analogous to those for the are not great enough to cause most evapotranspiration rates by 17 percent steady-state simulation. wells to go dry. Ground-water dis- (based on pan evaporation rates at charge to rivers would be reduced by Results of the steady-state simula- Staples during 1967-99), and (6) 23 percent (42 ft3/s) compared to tion indicate that the anticipated reducing average recharge by 25 per- increases in withdrawals will have a 1998-99 steady-state conditions as a cent. In addition to the above changes, result of the anticipated increases in minor effect on ground-water levels the stage of all rivers were lowered and streamflow in the area. Water lev- withdrawals during a drought (table 1.0 ft and hydraulic heads at the 3 els may decline an average of 0.03 ft 8). Although 42 ft /s is large com- boundaries were lowered 3.0 ft, to 3 regionally in the surficial aquifer with pared to 1.1 ft /s (0.6 percent) from coincide with the lowest levels mea- maximum declines of 0.3 ft near Simulation 2 (without a drought), it sured during this investigation. A Wadena. In the uppermost confined still represents less than 5 percent of transient simulation was also used to aquifers, water levels may decline an total streamflow in the area. investigate the effects of the antici- average of 0.08 ft regionally with Results of the transient simulation pated increases in withdrawals during maximum declines of 0.9 ft near indicate that the anticipated increases a 2-year drought. Changes made to Wadena. The anticipated increases in in withdrawals during a drought withdrawals would cause decreases in the transient simulation inputs were would generally increase seasonal ground-water discharge to streams of analogous to those for the steady-state declines in the surficial and upper- about 0.6 percent (1.1 ft3/s) of 1998- simulation. most confined aquifers less than 1 and 99 steady-state conditions, as well as The normal (1961-90) annual pre- 2 ft, respectively. Maximum increases small decreases in ground-water cipitation at Wadena is 26.24 in. in seasonal water level declines for evapotranspiration. Results of the Assuming recharge correlates directly the aquifers were 1.54 and 6.89 ft, transient simulation similarly indicate with precipitation, the 25 percent respectively. The maximum declines

41 95°15' 95°07'30" 95° 94°52'30" 94°45'

46°37'30" 6 Ck. 1 6 Sebeka 1 6 1 6 1 6 1 Red Beaver Creek Strike Lake T Granning 136 Lake Oylen N Eye Farnham

Creek

Crow Hay Creek 31 36 31 36 31 36 31 36 31 36 Creek Martin Creek Blue 6 1 6 1 6 1 6 Sand 1 6 1 River Lake Tower Sugar Creek Mud Creek Lake Little T 46°30' OTTER TAIL WADENA Farnham COUNTY COUNTY Lake CASS 135 N Bluff River COUNTY Leaf River Pulver Creek Creek Bluffton Leaf Lake

Creek 31 36 31 0.5 36 31 1.536 1.531 1.0 36 0.531 Iron 36 1.0 Ck. Radabaugh 6 1 6 1 1 6 1 1 1.5 Wadena 1.0 6 Lake6 2.0 2.0 River Ck. 1.0 0.5 0.5 Rice Simon South

1.5 Lovejoy Lake Creek Creek 4.0 Lake 0.5 Lake Wing 0.5 T

Whiskey Farber Cat 134 Lake Lake N Union 1.0 Verndale Johnson Wing River Lake 0.5 0.5 Dog 0.5 1.5 1.0 Lake 0.5 1.0 0.5 2.0 31 36 31 31 Aldrich 2.5 46°22'30" 36 36 31 Creek 0.5 36 31 36 Bluff 1.5 2.0

6 1 6 Staples Benz 1 1.0 2.0 1 6 1 6 1 6 Dower Lake Moran Lake 2.5 River 1.5 3.0

Oak Stones R. Tucker Creek Edwards Lake Hayden Lake 2.5 Hewitt Lake T 2.0 TODD Hayden Lake Jacobson 133 Munn Lake River COUNTY Lawrence N South Bear Lake Lake Prairie Jasmer Partridge Lake

Long Partridge

Creek S. 31 36 31 36 31 36 31 36 31 36

EXPLANATION

Extent of surficial aquifer

Area where surficial aquifer is absent

1.5 Line of equal simulated drawdown--Interval 0.5 feet

Figure 16a. Extent of surficial aquifer and s imulated drawdowns for model layer 1, representing the surficial aquifer, due to historical ground-water withdrawals, steady-state simulation, southern Wadena County and parts of surrounding counties, Minnesota.

42 95°15' 95°07'30" 95° 94°52'30" 94°45'

46°37'30" 6 Ck. 1 6 Sebeka 1 6 1 6 1 6 1 Red Beaver 0.5 Creek Strike Lake T Granning 136 Lake Oylen N Eye Farnham

Creek

Crow Hay Creek 31 36 31 36 31 36 31 36 31 36 Creek Martin Creek Blue 6 1 6 1 6 1 6 Sand 1 6 1 River Lake Tower 0.5 Sugar Creek Mud Creek Lake Little Farnham T 46°30' OTTER TAIL WADENA COUNTY COUNTY Lake CASS 135 N Bluff River COUNTY Leaf River Pulver Creek Creek Bluffton Leaf Lake

Creek 31 36 31 36 31 36 31 1.5 36 31 Iron 36 Ck. 1.5 Radabaugh 6 1 6 6 1 2.51 2.0 1 6 1 Lake

0.5 Wadena 1.0 6

2.0 1.5 2.0 River Ck. 1.0 Rice 0.5 Simon South

1.5 Lovejoy Lake Creek Creek Lake 1.0 1.0 4.0 0.5 Lake Wing T 1.5 Whiskey 1.5 Farber Cat 134 Lake Lake N Union Verndale Johnson Wing River Lake 2.0 Dog Lake 2.0 31 2.5 36 31 31 Aldrich 46°22'30" 36 36 31 Creek 36 31 36 Bluff 4.5 0.5 1.0 6 6 Benz 1 1 1 6 0.5 1 6 Staples 1 6 Dower Lake Moran 2.0 River

1.5 1.0 2.5 1.0Lake 1.0 1.0

Oak Stones R. Tucker 1.5 Creek Edwards 0.5 Lake Hayden Lake Hewitt Lake T 2.0 Hayden 2.0 2.0 1.5 1.5 TODD Lake Jacobson 133 Munn Lake River

COUNTY Lawrence N South

Bear ge Lake 4.5 2.5 0.5 Lake Prairie Jasmer Partridge Lake

Long Partrid

Creek S. 31 36 31 36 31 36 31 36 31 36

EXPLANATION

2.0 Line of equal simulated drawdown--Interval 0.5 feet

Figure 16b. Simulated drawdowns for model layer 3, representing the uppermost confined aquifers, due to historical ground-water withdrawals, steady-state simulation, southern Wadena County and parts of surrounding counties, Minnesota.

43 95°15' 95°07'30" 95° 94°52'30" 94°45'

46°37'30" Ck. 6 4 2 4 4 1 6 Sebeka 1 6 2 1 6 1 6 1 Red Beaver 4 Creek 2 Strike Lake T 136 Granning 4 Lake Oylen N Eye 2 Farnham

Creek

Crow Hay Creek 31 36 31 36 31 36 31 36 31 36 Creek Creek 4 4 Martin Blue 6 1 6 1 6 1 6 Sand 1 6 1 River Lake Tower Sugar

Creek 2 2 Creek 2 Mud 1 Lake Little T 46°30' OTTER TAIL WADENA Farnham COUNTY COUNTY Lake CASS 135 2 2 N Bluff River COUNTY Leaf River Pulver Creek Creek Bluffton Leaf 2 2 Lake Creek 31 36 31 4 36 31 36 31 36 31 Iron 36 4 Ck. 6 Radabaugh 6 1 6 6 1 1 1 6 1 Lake Wadena 4 6 6 River 2 Ck. 4 Rice

South

1 Simon 1

Lovejoy Lake

Creek Creek Wing Lake 2 Lake 2 T Whiskey Farber Cat 134 Lake Lake 2 N Union Verndale 2 Johnson 4 Wing River Lake 2 2 4 Dog 2 Lake

31 36 31 31 Aldrich 46°22'30" 36 36 31 Creek 36 31 36 Bluff 4 2 2 6 6 Benz 1 1 1 6 1 6 Staples 1 6 2 Dower Lake Moran Lake River

Oak Stones R. Tucker Creek Edwards Lake Hayden Lake Hewitt Lake T 1 TODD Hayden Lake Jacobson 133 Munn Lake 2 River COUNTY 2 Lawrence N South Bear Lake Lake Prairie Jasmer Partridge Lake Long 2 Partridge Creek S. 31 36 31 36 31 36 31 1 36 31 36

EXPLANATION

Extent of surficial aquifer

Area where surficial aquifer is absent

2 Line of equal simulated drawdown--Interval is variable, in feet

Figure 17a. Extent of surficial aquifer and s imulated drawdowns for model layer 1, representing the surficial aquifer, due to anticipated increased ground-water withdrawals and drought conditions, steady-state simulation, southern Wadena County and parts of surrounding counties, Minnesota.

44 95°15' 95°07'30" 95° 94°52'30" 94°45' 46°37'30" 64 Ck. 6 1 6 Sebeka 1 6 1 6 1 6 1 Red 8 Beaver 10 2 Creek Strike Lake 15 20 25 T Granning 136 4 2 Lake Oylen 4 4 N Eye 2 Farnham

Creek

30 Crow Hay Creek 31 36 31 4 36 31 36 31 36 31 36 Creek 25 Martin Creek Blue 1 6 6 1 6 10 6 20 15 8 1 Sand 1 6 1 6 River Lake Tower 4 Sugar Creek 6 Mud Creek Lake 2 Little Farnham T 46°30' OTTER TAIL WADENA 1 COUNTY COUNTY Lake CASS 135 N Bluff River COUNTY 2 Leaf River Pulver Creek Creek Bluffton Leaf 2 Lake

Creek 31 36 31 36 4 31 36 31 36 31 Iron 36 4 Ck. Radabaugh 6 2 6 1 6 1 1 6 1 1 Wadena 6 Lake6

6 River Ck. Rice Simon South

Lovejoy Lake Creek Creek Lake 2 Lake Wing 6 T Whiskey Farber Cat 134 Lake Lake Verndale N Union 4 2 Johnson Wing River Lake 4 2 Dog

Lake

2 31 36 31 31 Aldrich 46°22'30" 36 36 31 Creek 36 31 36 Bluff

6 4 Benz 1 6 6 Staples 1 6 1 2 1 6 1 4 Dower Lake Moran Lake River

Oak Stones 1 R. Tucker Creek Edwards Lake 4 Lake Hayden 6 Hewitt Lake T TODD Hayden Lake Jacobson 133 Munn Lake River

8 COUNTY Lawrence N South Bear ge Lake 2 Lake Prairie Jasmer 2 Partridge Lake

Long Partrid

Creek S. 31 36 31 36 2 31 36 31 1 36 31 36

EXPLANATION

1 Line of equal simulated drawdown--Interval is variable, in feet

Figure 17b. Simulated drawdowns for model layer 3, representing the uppermost confined aquifers due to anticipated increased ground-water withdrawals and drought conditions, steady-state simulation, southern Wadena County and parts of surrounding counties, Minnesota.

45 occurred during the late summer each Declines in the northern, eastern, and MODEL LIMITATIONS AND year. The long-term (net) decline in south-central parts of the study area ACCURACY OF RESULTS water level for the 2-year simulation were less than 0.4 ft due to lack of at any one location was 0.3 ft or less, wells completed in the uppermost A numerical ground-water-flow indicating that water levels did not confined aquifers. Model results indi- model is a practical tool for simulat- fully recover from seasonal withdraw- cate that greater than anticipated ing the response of the stream-aquifer als during the drought. Streamflow system to anticipated climatic condi- increases in withdrawals would cause reductions were least during the tions and development patterns. decreases in ground-water discharge spring and early summer and were However, the model necessarily is a to streams of about 1.4 percent (2.5 greatest during the late summer. 3 simplification of a complex flow sys- ft /s) of 1998-99 steady-state condi- tem. Accuracy of the simulations is Greater Than Anticipated Increases tions. limited by accuracy of the data used in Withdrawals Greater Than Anticipated Increases to describe the properties of the aqui- Simulation 4 (table 8) was fers and confining units, areal designed to evaluate the steady-state in Withdrawals During a Drought recharge rates, ground-water with- effects of greater than anticipated drawal rates, streambed hydraulic Simulation 5 (table 8) was conductivities, and boundary condi- increases in withdrawals on water lev- designed to evaluate the steady-state els and streamflow. This was simu- tions. Quantitative field data for these effects of greater than anticipated lated by making the following variables would greatly enhance increases in withdrawals on water lev- changes to the model compared to the model accuracy and, therefore, the 1998-99 steady-state rates: (1) els and streamflow during a typical simulated responses to anticipated increasing withdrawals from the 113 drought. For this simulation, the con- increases in withdrawals and drought. irrigation and commercial wells and ditions of greater than anticipated In addition, a different combination of 47 dug pits in the surficial aquifer by increases in withdrawals described in input could produce the same result. 20 percent, (2) increasing irrigation the previous section were superim- Caution should be used in making well withdrawals from the uppermost posed on the conditions of the hypo- ground-water management decisions confined aquifers by 50 percent, and thetical drought described previously. based on the model simulations (3) increasing withdrawals from the 5 described in this report. Actual water- Wadena municipal wells in the upper- Simulated results of greater than level declines in wells will differ from most confined aquifers by 40 percent. anticipated increases in withdrawals computed values and declines in or Average steady-state recharge was during a drought were very similar to near individual high-capacity wells assumed for the simulation. those based only upon effects of the generally will be greater. Steady-state Model results indicate that greater hypothetical drought (figs. 17a and simulations do not consider water than anticipated increases in with- 17b), only magnified slightly. Model from storage, which may appreciably drawals will have minimal effects on results indicate that water-level affect short-term changes in water ground-water levels and streamflow declines in the surficial aquifer of as levels. Pumping from wells in a con- in the area. In the surficial aquifer, much as 6.4 ft may occur in Wadena fined aquifer results in a reduced con- water levels may decline an average and in the central part of the aquifer fining-bed porosity and a corresponding reduction in drainage of 0.09 ft regionally, with maximum south of the Leaf River. Simulated of water from the confining bed. Con- declines of 0.5 ft near Wadena, south- declines in the uppermost confined sequently, less water is available for west of Verndale, and south of the aquifers for much of T133N, R35W Leaf River near its confluence with withdrawal and water-level declines range from 8 to 10 ft due to withdraw- increase after an aquifer has been the Red Eye River. In the uppermost als from irrigation wells. Declines in confined aquifers, model results indi- stressed for an extended period of the uppermost confined aquifers north cate that water levels may decline an time. of the Leaf River may be as much as average of 0.13 ft regionally, with Use of the calibrated model as a maximum declines of 0.8 to 2.1 ft 30.6 ft. Ground-water discharge to management tool is based on the near Wadena and near a few irrigation streams would be reduced by 25 per- premise that if historical conditions in 3 wells in the southwestern part of the cent (44 ft /s) compared to 1998-99 the aquifer can be simulated accu- study area, southwest of Verndale, and steady-state conditions as a result of rately, then future hydrologic condi- south of the Leaf River near its con- the greater than anticipated increases tions of similar magnitude can also be fluence with the Red Eye River. in withdrawals during a drought. simulated. The duration of the hypo-

46 thetical simulation period should be This premise holds true for the simu- much different than for the calibration the same as or less than the duration lation of anticipated increases in with- simulations. Therefore, the results of of the calibration period, which is the drawals and average recharge Simulations 3-5 should be viewed case for the transient simulations. In (Simulation 2). However, for the sim- with caution and regarded only as addition, the rate of simulated ulations of greater than anticipated plausible indicators of the response of recharge to or discharge from the increases in withdrawals or drought ground-water levels and streamflow aquifer should be similar to those conditions (Simulations 3-5), the to the hypothetical stresses. used in the calibration simulations. recharge and withdrawal rates are SUMMARY outside the study area. Discharge from the surficial aquifer is by withdrawals from wells, by ground-water evapotrans- Although numerous wells and test holes have been piration, and to streams. Discharge from the uppermost completed in the uppermost confined aquifers in the confined aquifers is by withdrawals from wells and to the Wadena area, little is known about the continuity or the surficial aquifer in river valleys. The theoretical maximum hydraulic response of the aquifers to ground-water with- well yields for the uppermost confined aquifers range from drawals. Water managers of the Minnesota Department of less that 175 gal/min to greater than 2,000 gal/min and are Natural Resources and the Wadena Soil and Water Conser- greatest in areas of greatest aquifer thickness and transmis- vation District are concerned about the increase of ground- sivity. water withdrawals from high-capacity wells completed in these aquifers. To address these concerns, and to evaluate A numerical model of ground-water flow was con- the ground-water resources in the uppermost confined aqui- structed based on knowledge of the hydrogeologic setting, fers in southern Wadena County, an investigation was con- aquifer characteristics, distribution and amount of recharge ducted during 1997–2000 by the U.S. Geological Survey, in and discharge, and aquifer boundaries. The simulated water cooperation with the Minnesota Department of Natural budget for the calibrated steady-state simulation indicated Resources and the Wadena Soil and Water Conservation that areal recharge to the surficial aquifer accounts for 86.9 District. percent of the sources of water to the aquifers, with leakage The hydrogeologic units of primary interest in the to the uppermost confined aquifers where the surficial aqui- study area are the surficial aquifer, the uppermost confining fer is absent contributing 6.9 percent. The largest dis- units, and the uppermost confined aquifers. The surficial charges from the aquifers are leakage from the surficial aquifer underlies all but portions of the eastern, western, aquifer to streams (54.5 percent) and ground-water evapo- and south-central parts of the study area, and is as much as transpiration (41.4 percent). The simulated transient water 70 ft thick. The uppermost buried sand and gravel lenses of budget for 1999 indicated that the principal sources of appreciable thickness in a vertical section at a location con- water to the aquifers were areal recharge to the surficial stitutes the uppermost confined aquifers. Thickness of the aquifer during the spring and early summer stress periods uppermost confined aquifers in the study area is as much as and release from storage during the winter, late summer, 72 ft. The thickness of the aquifers is greatest in the south- and fall stress periods. The principal discharges were central and west-central parts of the study area, with thick- stream-aquifer leakage during the fall and winter stress nesses greater than 50 ft. Depth to the top of the uppermost periods, addition to storage during the spring and early confined aquifers ranges from 23 to 132 ft. The thickness summer stress periods, and ground-water evapotranspira- of the uppermost confining units ranges from 4 to 132 ft, tion during the late summer stress period. but generally is less than 50 ft thick where the surficial The calibrated ground-water flow model was used as a aquifer is present. tool to evaluate ground-water availability in the study area The regional direction of flow in the uppermost con- by assessing the potential effects of hypothetical conditions fined aquifers is to the east, southeast, and southwest on ground-water levels and streamflow. Model results indi- toward the Crow Wing River in the eastern part of the study cate that historical withdrawals have lowered water levels area and toward the Leaf River in the western part. regionally in the surficial and uppermost confined aquifers Recharge to the surficial aquifer occurs by infiltration of an average of 0.31 and 0.42 ft, respectively. Declines in the precipitation to the saturated zone (areal recharge). Esti- surficial aquifer have been greatest near Wadena (4.0 ft) mated areal recharge to the surficial aquifer averaged 13.9 and Staples (2.5 ft). Model results also indicate that ground in./yr during 1998, and 11.5 in./yr during 1999, based on water discharge to rivers has been reduced by less than one hydrograph analysis. Sources of water to the uppermost percent compared to predevelopment conditions. confined aquifers are leakage of water through overlying Model results indicate that the anticipated increases in till and clay and ground-water flow from adjoining aquifers withdrawals will have a minor effect on ground-water lev-

47 els and streamflow in the area. Water levels may decline an great enough to cause most wells to go dry. Ground water average of 0.03 ft regionally in the surficial aquifer with discharge to rivers would be reduced by 23 percent (42 maximum declines of 0.3 ft near Wadena. In the uppermost ft3/s) compared to 1998-99 steady-state conditions. Results confined aquifers, water levels may decline an average of of the transient simulation indicate that the anticipated 0.08 ft regionally with maximum declines of 0.9 ft near increases in withdrawals during a drought would increase Wadena. The anticipated increases in withdrawals would seasonal declines in the surficial and uppermost confined cause decreases in ground-water discharge to streams of aquifers less than 1 and 2 ft, respectively. about 0.6 percent (1.1 ft3/s) of 1998-99 conditions, as well as small decreases in ground water evapotranspiration. Model results indicate that greater than anticipated Results of the transient simulation similarly indicate that increases in withdrawals during periods of average water levels will be minimally affected by the anticipated recharge will have minimal effects on ground-water levels increases in pumping. The maximum increase in seasonal and streamflow in the area. In the uppermost confined aqui- water-level decline for the uppermost confined aquifers fers, for example, water levels may decline an average of would be 1.34 ft. 0.13 ft regionally, with maximum declines of 0.8 to 2.1 ft Model results indicate that the anticipated increases in near Wadena and Verndale. Greater than anticipated withdrawals during a drought may lower water levels 2 to 4 increases in withdrawals would cause decreases in ground- 3 ft regionally in much of both the surficial and uppermost water discharge to streams of about 1.4 percent (2.5 ft /s) confined aquifers. Water-level declines in the surficial of 1998-99 steady-state conditions. Greater than antici- aquifer of about 6 ft may occur in Wadena and in the cen- pated increases in withdrawals during a drought may cause tral part of the aquifer south of the Leaf River. Simulated and average decline of 6 ft in the uppermost confined aqui- declines in all aquifers as a result of the anticipated fers and a reduction in ground-water discharge to streams increased withdrawals and hypothetical drought are not of about 25 percent. REFERENCES Geological Survey Water- Falls, South Dakota: U.S. Geolog- Resources Investigations Report ical Survey Water-Supply Paper Allison, I.S., 1932, The geology and 88–4124, 138 p. 2024, 50 p. water resources of northwestern _____1990, Hydrogeology and simu- Leverett, F., 1932, Quaternary geol- Minnesota: Minnesota Geologi- lation of ground-water flow in the ogy of Minnesota and parts of cal Survey Bulletin 22, 245 p. 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48 Wing River watershed, central quality appraisal of sand-plain Hubbard Counties, Minnesota: Minnesota: U.S. Geological Sur- aquifers in Hubbard, Morrison, U.S. Geological Survey Water- vey Hydrologic Investigations Otter Tail, and Wadena Counties, Resources Investigations Report Atlas HA–380, 4 pls. Minnesota: U.S. Geological Sur- 89–4136, 135 p. McDonald, M.G., and Harbaugh, vey Water-Resources Investiga- Theis, C.V., 1935, The relation A.W., 1988, A modular three- tions Report 84–4080, 49 p. between the lowering of the pie- dimensional finite-difference Norris, S.E., 1962, Permeability of zometric surface and the rate and ground-water flow model: U.S. glacial till: U.S. Geological Sur- duration of discharge of a well Geological Survey Techniques of vey Research 1962, p. E150– using ground-water storage: Water-Resources Investigations, E150. American Geophysical Union book 6, chap. A1, 586 p. Norris, S.E., and Fidler, R.E., 1969, Transactions, v. 16, p. 519–524. Meyer, R.R., 1963, A chart relating Hydrogeology of the Scioto River U.S. Department of Commerce, well diameter, specific capacity, Valley near Piketon, south-central National Oceanic and Atmo- and the coefficients of transmissi- Ohio: U.S. Geological Survey spheric Administration, Midwest bility and storage, in Bentall, Ray, Water-Supply Paper 1872, 70 p. Climate Center, National Oceanic compiler, Methods of determining Prince, K.R., Franke, O.L., and and Atmospheric Administration permeability, transmissibility, and Reilly, T.E., 1987, Quantitative precipitation data available on the drawdown: U.S. Geological Sur- assessment of the shallow ground- World Wide Web; accessed vey Water-Supply Paper 1536-I, water flow-system associated with March 8, 1999, at URL p. 338–340. Connetquot Brook, Long Island, http://mcc.sws.uiuc.edu/ Miller, R.T., 1982, Appraisal of the New York: U.S. Geological Sur- Wright, H.E., Jr., and Ruhe, R.V., Pelican River sandplain aquifer, vey Water-Supply Paper 2309, 1965, Glaciation of Minnesota western Minnesota: U.S. Geologi- 28 p. and Iowa, in Wright, H.E., Jr., and cal Survey Open-File Report 82– Rasmussen, W.C., and Andreasen, Frey, D.G., eds., The Quaternary 347, 44 p. G.G., 1959, Hydrologic budget of of the United States: Princeton, Morris, D.A., and Johnson, A.I., the Beaver Dam Creek Basin, New Jersey, Princeton University 1967, Summary of hydrologic and Maryland: U.S. Geological Sur- Press, p. 29–41. physical properties of rock and vey Water-Supply Paper 1472, Yager, R.M., 1993, Estimation of soil materials, as analyzed by the 106 p. hydraulic conductivity of a river- hydrologic laboratory of the U.S. Stark, J.R., Busch, J.P., and Deters, bed and aquifer system on the Geological Survey 1948–60: U.S. M.H., 1991, Hydrogeology and Susquehanna River in Broome Geological Survey Water-Supply water quality of glacial-drift aqui- County, New York: U.S. Geologi- Paper 1839–D, 42 p. fers in the Bemidji-Bagley area, cal Survey Water-Supply Paper Myette, C.F., 1984, Ground-water- Beltrami, Clearwater, Cass, and 2387, 49 p.

49 GLOSSARY Alluvial deposits: Gravel, sand, silt, and clay deposited in channels and floodplains of modern streams. Aquifer: Formation, group of formations, or part of a formation that contains sufficient saturated permeable material to yield significant quantities of water to wells or springs. Areal recharge: Recharge to the aquifer by infiltration of precipitation to the saturated zone. Base flow: Sustained streamflow, consisting mainly of ground-water discharge to a stream. Confined aquifer: Aquifer bounded above by a confining unit. An aquifer containing confined ground water. Synonymous with buried aquifer. Confining unit: Body of materials with low vertical permeability stratigraphically adjacent to one or more aquifers. Drawdown: Vertical distance between the static (nonpumping) hydraulic head and hydraulic head caused by pumping. Evapotranspiration: Water discharge to the atmosphere by evaporation from water surfaces and moist soil and by plant transpiration. Gaining stream: Stream or reach of a stream whose flow is being increased by inflow of ground water. Ground water: The part of subsurface water that is in the saturated zone. Ground-water evapotranspiration: Water discharged to the atmosphere from ground water by direct evaporation from the water table where it is at or near land surface and transpiration from vegetation where the water table is above the root zone or within reach of roots through capillary action; does not include evapotranspiration losses occurring above the water table. Head, hydraulic: The height, above a standard datum, of the surface of a column of water that can be supported by the static pressure at a given point. Hydraulic conductivity: Capacity of porous material to transmit water under pressure. The rate of flow of water passing through a unit section or area under a unit hydraulic gradient. Hydraulic gradient: The change in hydraulic head per unit distance of flow in a given direction. Synonymous with potentiometric gradient. Losing stream: Stream or reach of a stream whose flow is being decreased by leakage to ground water. Nested wells: Two or more wells at the same location completed at different depths below land surface. Outwash: Washed, sorted, and stratified drift deposited by water from melting glacier ice. Permeability: Measure of the relative ease with which a porous medium can transmit a fluid under a potential gradient. Potentiometric surface: A surface that represents the static head of water in an aquifer, assuming no appreciable variation of head with depth in the aquifer. It is defined by the levels to which water will rise in tightly cased wells from a given point in an aquifer. Saturated zone: The zone in which all voids are ideally filled with water. The water table is the upper limit of this zone. Water in the saturated zone is under pressure equal to or greater than atmospheric. Specific capacity: The rate of discharge of water from a well divided by the drawdown of water level within the well. Specific yield: The ratio of the volume of water that aquifer material will yield by gravity drainage to the volume of the aquifer material. Steady state: Equilibrium conditions whereby hydraulic heads and the volume of water in storage do not change substantially with time. Storage coefficient: The volume of water an aquifer releases from or takes into storage per unit surface area of the aquifer per unit change in head. In an unconfined aquifer, it is the same as specific yield. Stream-aquifer leakage: Movement of water between a stream and the underlying aquifer, not restricted to either direction of flow. Surficial aquifer: The saturated zone between the water table and the first underlying confining unit. Synonymous with unconfined aquifer. Till: Unsorted, unstratified drift deposited directly by glacier ice. Transmissivity: The rate at which water of the prevailing kinematic viscosity is transmitted through a unit width of an aquifer under a unit hydraulic gradient. Unconfined aquifer: The saturated zone between the water table and the first underlying confining unit. Synonymous with surficial aquifer. Water table: The surface in an unconfined ground-water body at which the water pressure is atmospheric. Generally, that is the potentiometric surface of the upper part of the zone of saturation.