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Suggested citation:

Hansen, C.V., 2009, Status of ground-water levels and storage volume in the 

Equus Beds aquifer near Wichita, Kansas, July 2008: U.S. Geological Survey 

Scientific Investigations Map 3075, 1 sheet.

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Status of Ground-Water Levels and Storage Volume in the 

Equus Beds Aquifer Near Wichita, Kansas, July 2008

By

Cristi V. Hansen

2009

Introduction

Beginning in the 1940s, the Wichita well field was developed in the Equus

Beds aquifer in southwestern Harvey County and northwestern Sedgwick County 

to supply water to the city of Wichita (Williams and Lohman, 1949). In addition to 

supplying drinking water to the largest city in Kansas, the other primary use of water 

from the Equus Beds aquifer is to irrigate crops in this agriculture-dominated part 

of south-central Kansas (Rich Eubank, Kansas Department of Agriculture, Division 

of Water Resources, oral commun., 2008). The decline of water levels in the aquifer 

were noted soon after the development of the Wichita well field began (Williams and 

Lohman, 1949). As water levels in the aquifer decline, the volume of water stored 

in the aquifer decreases and less water is available to supply future needs. For many 

years the U.S. Geological Survey (USGS), in cooperation with the city of Wichita, 

has monitored these changes in water levels and the resulting changes in storage 

volume in the Equus Beds aquifer as part of Wichita’s effort to effectively manage 

this resource. In 2007, the city of Wichita began large-scale artificial recharge of the 

Equus Beds aquifer using water from the Little Arkansas River—either pumped from 

the river directly or from wells in the riverbank that obtain most of their water from 

the river by induced infiltration (City of Wichita, 2009).

Hydrogeology of the Study Area

The study area (fig. 1) includes about 165 square miles (mi2) and is located 

in Harvey and Sedgwick Counties northwest of Wichita, Kansas. The study area is 

bounded on the southwest by the Arkansas River and on the northeast by the Little 

Arkansas River. There is little topographic relief in the study area. For the most 

part, the land surface slopes gently toward the major streams in the study area. The 

Wichita well field is in the central part of the study area (fig. 1). The central part of 

the study area is the historic center of pumping in the study area and includes wells 

used to supply water to the city of Wichita and for irrigation.

Quaternary deposits occur throughout the study area primarily as alluvial deposits. These alluvial deposits, known locally as the Equus beds, are as much as 250 

feet (ft) thick in the study area (Leonard and Kleinschmidt, 1976). The Equus beds 

primarily consist of sand and gravel interbedded with clay or silt, but locally may 

primarily consist of clay with thin sand and gravel layers (Lane and Miller, 1965a; 

Myers and others, 1996). The middle part of the deposits generally has more finegrained material than the lower and upper parts (Lane and Miller, 1965b, Myers and 

others, 1996). The Wellington Formation of Permian age underlies the Quaternary 

deposits in the study area and forms the bedrock confining unit below these deposits; 

it is about 700 ft thick (Bayne, 1956). 

The Equus Beds aquifer is the easternmost extension of the High Plains aquifer 

in Kansas (Stulken and others, 1985; Hansen and Aucott, 2001). The Equus beds 

are an important source of ground water because of the generally shallow depth 

to the water table, the large saturated thickness, and generally good water quality. 

Near the Arkansas River, the water table may be as little as 10 ft below land surface. 

Farther from the Arkansas River and near the Little Arkansas River, the water table 

is at a greater depth, depending on the altitude of the land surface and the amount of 

water-level decline that has been caused by ground-water withdrawals. The saturated 

thickness of the Equus Beds aquifer within the study area ranges from about 75 ft 

near the Little Arkansas River to almost 250 ft near the Arkansas River where the 

lowest areas of the underlying bedrock surface occur (Spinazola and others, 1985).

The Equus Beds aquifer is considered to be an unconfined aquifer, but the presence 

of clay layers has resulted in semi-confined conditions in some areas (Spinazola and 

others, 1985; Stramel, 1967). Storage volume (the amount of water available for use) 

of the Equus Beds aquifer in the study area is estimated at about 2,100,000 acre-feet 

(acre-ft) (Hansen, 2007).

Methods

The July 2008 water-level measurements were collected during July 2 to 23, 

2008, from 116 historic observation wells and 38 areal index wells. The historic 

observation wells have been used by the city of Wichita for monitoring water levels 

in the Equus Beds aquifer since the 1940s (Stramel, 1956). The areal index wells 

were installed in 2001 and 2002 to monitor the effects of artificial recharge on the 

water quality and water levels in the Equus Beds aquifer and to determine if there are 

water-quality differences between the shallow and deep parts of the aquifer (Andrew 

Ziegler, U.S. Geological Survey, oral commun., September 2003). Water levels in the 

historic observation wells were measured by city of Wichita personnel; water levels 

in the areal index wells were measured by Equus Beds Groundwater Management 

District No. 2 (GMD2) personnel. Both agencies used standard water-level measurement techniques that are similar to USGS methods described in Stallman (1971). The 

historic observation well data are on file in paper and electronic form with the city of 

Wichita Water and Sewer Department in Wichita, Kansas; the areal index well data 

collected by GMD2 are stored in the Kansas Geological Survey’s (KGS’s) Water 

Information and Storage and Retrieval Database (WIZARD) and are available at the 

following URL: http://www.kgs.ku.edu/Magellan/WaterLevels/index.html The waterlevel data used in this report from both the historic monitoring wells and the areal 

index wells also are stored by the USGS in the National Water Information System 

(NWIS) database and are available at the following URL: http://waterdata.usgs.gov/

ks/nwis

The water-level change since August 1940 at a well was determined by subtracting the depth to water below land surface in July 2008 from the depth to water 

below land surface at the same well in August 1940. Of the 154 wells used in this 

report, 40 had measured water levels for August 1940 and 114 did not. If an August 

1940 water-level measurement did not exist for a well in the study area, one was 

estimated from the August 1940 water-level altitude map of Stramel (1956) as modified by Aucott and Myers (1998). The August 1940 to July 2008 water-level change 

values were plotted on the map and manually contoured. 

Change in storage volume for the purposes of this report is defined as the 

change in saturated aquifer volume multiplied by the specific yield of the aquifer. A 

specific yield of 0.2 has been used to compute the changes in storage volume in the 

Equus Beds aquifer since Stramel (1956) first computed storage volume for the aquifer. The use of a specific yield of 0.2 was retained in this report because, as noted by 

Hansen and Aucott (2001), it is within the range of most estimates of specific yield, 

and because there is no general agreement on an average value of specific yield for 

the Equus Beds aquifer in the study area. 

The change in storage volume from August 1940 to July 2008 was computed 

using computer-generated Thiessen polygons (Thiessen, 1911) that were based on 

the measured water-level changes at wells and the manually drawn lines of equal 

water-level change. Theissen polygons apportion the water-level change at each well 

and at points representing the lines of equal water-level change to the area around 

the wells and points. The volume of storage change was computed by summing the 

area of each Theissen polygon multiplied by the actual water-level change associated 

with the Theissen polygon and then by the specific yield. To determine the storagevolume change since August 1940 in the entire study area and in the central part of 

the study area, the computation was done for the Theissen polygons within each of 

these areas. 

Changes in storage volume for periods that do not begin with August 1940 were 

calculated as the difference between changes in storage volume for August 1940 

to the beginning of the selected time period, and for August 1940 to the end of the 

selected time period. For example, the change in storage volume for January 1993 

to July 2008 was calculated as the change in storage volume for August 1940 to July 

2008 minus the change in storage volume for August 1940 to January 1993. 

Ground-Water Levels and Storage Volume, July 2008

Ground-water-level declines can result from a combination of factors, with 

pumpage and decreased recharge resulting from less-than-average precipitation being the primary factors. Droughts tend to decrease the amount of recharge 

available and increase demand for and thus pumpage of ground water, resulting 

in increased water-level declines. Periods of greater-than-average rainfall tend to 

increase the amount of recharge available and decrease the demand for and thus 

pumpage of ground water, resulting in water-level rises. If the water-level declines 

or rises are large enough, they may locally alter the direction of ground-water flow. 

An annual cycle of water-level declines and rises generally occurs in the study area. 

Typically, the largest water-level declines occur during the summer or fall when 

agricultural-irrigation and city pumpage are greatest (Aucott and Myers, 1998). 

This cycle of annual water-level declines is reflected in the annual fluctuation in the 

water levels in wells shown in figure 2. The consistently large seasonal water-level 

variations in well 104, for example, probably are because of agricultural-irrigation 

pumpage. 

Aucott and Myers (1998) pointed out that record to near-record low water levels occurred in the Equus Beds aquifer in January 1993. Recent reports have shown 

that since 1993, the Equus Beds aquifer has been experiencing higher water levels 

because of near-average to greater-than-average precipitation and decreased city 

pumpage (Aucott and Myers, 1998; Hansen and Aucott, 2001, 2004; Hansen, 2007). 

Pumpage for agricultural irrigation, which can vary as much as 40 percent from 

year to year, tended to decrease in years of greater-than-average precipitation and 

increase in years of average to less-than-average precipitation (Hansen, 2007); thus, 

decreased pumpage for agricultural irrigation likely contributed to the higher water 

levels only in years of greater-than-average precipitation. Water levels in wells in the 

study area have continued to remain relatively high, indicating this period of higher 

water levels that began in 1993 continued through July 2008 (fig. 2).

Water-level changes from August 1940 to July 2008 are shown in figure 3. 

Water levels were measured in the historic observation wells by city of Wichita 

personnel during July 2 to 17, 2008, and in the areal index wells by GMD2 personnel during July 21 to 23, 2008. Precipitation during July 2 to 17, 2008, ranged 

from 0.52 inch (in.) to 1.56 in. at five weather stations in and near the study area 

(Halstead, Hutchinson, Mount Hope, Newton, and Wichita); precipitation of 0 to 

0.06 in. occurred at these stations during July 21 to 23, 2008 (National Oceanic 

and Atmospheric Administration, 2008). Water-level changes from August 1940 to 

July 2008 ranged from a decline of 23.41 ft at well IW-06 in the northwest part of 

the study area to a rise of 3.58 ft at well P27 just beyond the west edge of the study 

area. Water-level declines of 20 ft or more occurred in two small areas around wells 

3 and IW-06 in the northern part of the study area. The decline centered around a 

non-pumping well (IW-06) is probably an artifact of changing pumping of well 1 

in the 21 day period between the measurement of wells 1 and IW-06. Surrounding 

these two areas of declines of 20 ft or more is a large area of water-level declines of 

10 or more ft that covers much of the central part of the study area (where Wichita 

city wells are located) and extends beyond it in the northern part of the study area. 

Another small area of declines of 10 ft or more occurs around well IW-04 in the 

northwest part of the study area. Small water-level rises of less than 2 ft occurred 

along the western edge of the study area and near the Little Arkansas River. Of 

special note are the two hachured contours around the two southern recharge sites 

RB-1 and RB-2 in T. 24 S., R. 3 W. (fig. 3). These hachured contours indicate areas 

of lesser decline around areas where the city of Wichita is artificially recharging the 

Equus Beds aquifer. Since March 2007, when Wichita began large-scale artificial 

recharge, 1,933 acre-ft of water have been artificially recharged into the aquifer 

through the six recharge sites shown in figure 3 (Wichita Water Utilities, written 

commun., 2008). Areas of lesser declines are not shown around the four northern 

recharge sites despite as much or more water being artificially recharged in 2008 

at RRW-1 than at RB-1 and at each of RRW-2, RRW-3, and RRW-4 than at RB-2 

(Wichita Water Utilities, written commun., 2008). Possible reasons for the lack of 

lesser decline areas around the four northern recharge sites include different hydrogeologic conditions in the northern part of the study area or ground-water pumpage 

that was greater near the northern artificial recharge sites than near the southern 

sites. Declines around the four northern artificial recharge sites probably would have 

been larger if the artificial recharge had not taken place.

The change in storage volume in the study area from August 1940 to July 

2008 was a decrease of about 134,000 acre-ft (fig. 2, table 1). The storage-volume 

in the study area in July 2008 was about 11,000 acre-ft less than in July 2007 and 

about 1,000 acre-ft more than in April 2008 (table 1). From August 1940 (which 

is just before Wichita began pumping water from the study area), to January 1993, 

when near-record low water levels and storage-volumes occurred in the study area 

because of a combination of drought conditions and increased usage, storage volume 

decreased by about 255,000 acre-ft in the study area (Aucott and Myers, 1998). The 

change in storage volume from January 1993 to July 2008 represents a recovery of 

about 121,000 acre-ft (table 1) or about 47 percent of the storage volume previously 

lost from August 1940 to January 1993. Precipitation in the study area during January to July, 2008, tended to be near normal except for May when precipitation was 

more than 3 in. above normal in much of the study area (http://www.srh.noaa.gov/

rfcshare/precip_analysis_new.php, accessed September 25, 2008), which probably 

contributed to the relatively high water levels and thus maintenance of the substantial storage-volume recovery following the low levels in January 1993.

The change in storage volume in the central part of the study area (where 

Wichita city wells are located) from August 1940 to July 2008 was a decrease of 

about 71,200 acre-ft (fig. 2, table 1). Storage volume in the central part of the study 

area in July 2008 was about 2,300 acre-ft more than in July 2007 and about 4,400 

acre-ft more than in April 2008 (table 1). From January 1993 to July 2008, storage 

volume in the central part of the study area increased by about 82,800 acre-ft 

(table 1) or about 54 percent of the storage volume previously lost from August 

1940 to January 1993; this is a slightly larger percentage recovery than occurred 

in the study area as a whole. In addition, a comparison of the changes in storage 

U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

Prepared in cooperation with the

CITY OF WICHITA, KANSAS

SCIENTIFIC INVESTIGATIONS MAP 3075

Status of ground-water levels and storage volume in the Equus Beds aquifer

Hansen, C.V., 2009, Status of ground-water levels and storage 

volume in the Equus Beds aquifer near Wichita, Kansas, July 2008

volume for the central part of the study area to those for the study area as a whole 

indicates that in recent years the recovery has been maintained more consistently in 

the central part of the study area than in the study area as a whole (fig. 2). This probably is because city pumpage, which occurs in the central part of the study area, has 

remained less than pre-1993 levels, whereas agricultural-irrigation pumpage, which 

occurs throughout the study area, has been as much or more than pre-1993 levels in 

some years (Hansen, 2007). 

References

Aucott, W.R., and Myers, N.C., 1998, Changes in ground-water levels and storage 

in the Wichita well field area, south-central Kansas, 1940–98: U.S. Geological 

Survey Water-Resources Investigations Report 98–4141, 20 p.

Aucott, W.R., Myers, N.C., and Dague, B.J., 1998, Status of ground-water levels and 

storage in the Wichita well field area, south-central Kansas, 1997: U.S. Geological 

Survey Water-Resources Investigations Report 98–4095, 15 p.

Bayne, C.K., 1956, Geology and ground-water resources of Reno County, Kansas: 

Kansas Geological Survey Bulletin 120, 130 p.

City of Wichita, 2009, Wichita area future water supply—a model program for other 

municipalities: Wichita, Kansas, accessed March 24, 2009, at http://www.wichitagov.org/CityOffices/WaterAndSewer/ProductionAndPumping/FutureWaterSupply.

htm 

Hansen, C.V., and Aucott, W.R., 2001, Status of ground-water levels and storage 

volume in the Wichita well field area, south-central Kansas, 1998–2000: U.S. 

Geological Survey Water-Resources Investigations Report 00–4267, 27 p.

Hansen, C.V., and Aucott, W.R., 2004, Status of ground-water levels and storage volume in the Equus Beds aquifer near Wichita, Kansas, January 2000–January 2003: 

U.S. Geological Survey Water-Resources Investigations Report 03–4298, 36 p.

Hansen, C.V., 2007, Status of ground-water levels and storage volume in the Equus

Beds aquifer near Wichita, Kansas, January 2003–January 2006: U.S. Geological 

Survey Scientific Investigations Report 2006–5321, 34 p.

Juracek, K.E., and Hansen, C.V., 1995, Digital maps of the extent, base, top, and 

1991 potentiometric surface of the High Plains aquifer in Kansas: U.S. Geological 

Survey Open-File Report 95–758, map scales 1:500,000 and 1:1,000,000.

Lane, C.W., and Miller, D.E., 1965a, Geohydrology of Sedgwick County, Kansas: 

Kansas Geological Survey Bulletin 176, 100 p.

Lane, C.W., and Miller, D.E., 1965b, Logs of wells and test holes in Sedgwick 

County, Kansas: Kansas Geological Survey Special Distribution Publication 22, 

175 p.

Leonard, R.B., and Kleinschmidt, M.K., 1976, Saline water in the Little Arkansas 

River Basin area, south-central Kansas: Kansas Geological Survey Chemical 

Quality Series 3, 24 p.

Myers, N.C., Hargadine, G.D., and Gillespie, J.D., 1996, Hydrologic and chemical 

interaction of the Arkansas River and the Equus Beds aquifer between Hutchinson and Wichita, south-central Kansas: U.S. Geological Survey Water-Resources 

Investigations Report 95–4191, 100 p.

National Oceanic and Atmospheric Administration, 2008, Climatological data, Kansas, July 2008: Asheville, North Carolina, v. 122, no. 7, 41 p. 

Spinazola, J.M., Gillespie, J.B., and Hart, R.J., 1985, Ground-water flow and solute 

transport in the Equus beds area, south-central Kansas: U.S. Geological Survey 

Water-Resources Investigations Report 85–4336, 68 p.

Stallman, R.W., 1971, Aquifer-test design, observation and data analysis: U.S. Geological Survey Techniques of Water-Resources Investigations, book 3, chap. B-1, 

p. 14–16.

Stramel, G.J., 1956, Progress report on the ground-water hydrology of the Equus

beds area, Kansas: Kansas Geological Survey Bulletin 119, part 1, 59 p.

Stramel, G.J., 1967, Progress report on the ground-water hydrology of the Equus

beds area, Kansas 1966: Kansas Geological Survery Bulletin 187, part 2, 27 p.

Stullken, L.E., Watts, K.R., and Lindgren, R.J., 1985, Geohydrology of the High 

Plains aquifer, western Kansas: U.S. Geological Survey Water-Resources Investigations Report 85–4198, 86 p.

Theissen, A.H., 1911, Precipitation averages for large areas: Monthly Weather 

Review, v. 39, p. 1,082–1,084.

Williams, C.C., and Lohman, S.W., 1949, Geology and ground-water resources of 

a part of south-central Kansas, with special reference to the Wichita municipal 

water supply: Kansas Geological Survey Bulletin 79, 455 p.

Figure 1. Location of study area near Wichita, south-central Kansas (modified from 

Aucott and Myers, 1998).

Study area

KINGMAN

COUNTY

Patterson

0 2 4 6 8 10 MILES

0 2 4 6 8 10 KILOMETERS

37o45'

38o

38o15'

97o45' 30' 97o15'

Arkansas

River

Kisiwa

River

Arkansas

Little

West

East

Emma 

Emma 

Creek

Sand 

Creek

Creek

Creek

RICECOUNTY

RENO

COUNTY

MARION

COUNTY

MCPHERSON

COUNTY

Approximate 

extent of High

Plains aquifer

in Kansas

SEDGWICK

COUNTY

HARVEY

COUNTY

Hesston

Newton

Bentley

Hutchinson

Emma

Creek

Halstead

Index map

Cheney

 Reservoir

North Fork

Ninnescah River 

KANSAS

Approximate boundary 

of Equus Beds aquifer

(from Juracek and

Hansen, 1995)

Andale

Park

City

Bel Aire

Wichita

Burrton

Central part 

of study area

Base from U.S. Geological Survey digital data, 1:100,000, 1983 

Lambert Conformal Conic Projection

Standard parallels 33° and 45°, central meridian 98°15'

Cow

Creek

Sedgwick

Mount

Hope Valley

Center

Figure 2. Water-level altitudes in observation wells 104 and 886 and Equus Beds aquifer 

storage-volume change in the study area and the central part of the study area (waterlevel-altitude data from Stramel (1956, 1967), and from data collected by city of Wichita, 

Equus Beds Groundwater Management District No. 2, and on file with U.S. Geological 

Survey. Location of observation wells is shown in figure 3. Storage-volume changes 

from Stramel (1956, 1967), Aucott and Myers (1998), Aucott and others (1998), Hansen 

and Aucott (2001, 2004), Hansen (2007), and data on file with U.S. Geological Survey in 

Lawrence, Kansas). 1938 1940 1945

195019551960

1965197019751980198519901995

2000

20052009

1,300

1,440

1,310

1,320

1,330

1,340

1,350

1,360

1,370

1,380

1,390

1,400

1,410

1,420

1,430

WATER-LEVEL ALTITUDE, IN FEET ABOVE NORTH 

AMERICAN VERTICAL DATUM OF 1988 (NAVD 88)

-300

400

-250

-200

-150

-100

-50

0

50

100

150

200

250

300

350

STORAGE-VOLUME CHANGE SINCE AUGUST 1940,

IN THOUSANDS OF ACRE-FEET

Storage-volume 

change in study area

Water-level altitude in well 104

Water-level altitude in well 886

Storage-volume change

in central part of study area

122

-2

0

-2

-2

-6 -8

-8

-8

-8

-10

-10

-12

-12

-12

-12

-12

-14

-14

-14

-14

-14

-14

-16

-16

-16

-18

-18

-18

-20

-18

-20

-6

-6

0

0

0

11 12

T.

25

S.

T.

24

S.

T.

23

S.

R. 3 W. R. 2 W. R. 1 W.

Base from U.S. Geological Survey digital data, 1:100,000, 1983 

Universal Transverse Mercator projection 

Zone 14

Horizontal coordinate information is referenced to the North American

 Datum of 1983 (NAD 83)

0 1 2 3 4 5 6 MILES

0 1 2 3 4 5 6 KILOMETERS

Little

Arkansas

River

River

Emma

Emma

West

Creek

Creek

Creek

Sand

Arkansas

Mount

Hope

Burrton

Bentley

Sedgwick

Little

P32

P30

P29

118

P35

3034

892

47

109

130 41

18

26

1189

1173

1175

15

19

20

133

29

3041

P28

880

44

3035

3001

821

103

104

101

3 4

2

7

878

886

5

6

506

3038

8

9 16

17 1190

2084

3033

833

1187

1186

50 49

48

45

Patterson

110 3002

21 112

22

23

839

24 28 25

54

55

52

114

53

51

842

840 30 32 34 35

33

36

1176 124

1179

826

115 3044

816 37

38

39

40

815

126

810

3050

Arkansas

102

Kisiwa

1

3004

870

Creek

13

27

P27

10

46

River

14

120

-4

-4

-4

-2

-4

31

108

-16

-6

-6

-10

-6

-8

P31

3036

105

3032

HARVEY COUNTY

SEDGWICK COUNTY

-10

-12

-22

-10

-16

IW-01

IW-02

IW-08

IW-09

IW-14

IW-13

IW-18

IW-19

IW-24 IW-25

IW-30

IW-31

IW-35

IW-32

IW-33

IW-34 

IW-38

IW-37 IW-36

IW-27

IW-28

IW-29

IW-20 IW-21 IW-22 IW-23

IW-10

IW-15

IW-16

IW-17

IW-11

IW-06

IW-12

IW-05

IW-03

IW-26

IW-04

Valley

Center

42

IW-07

Halstead

Boundary of 

study area

Boundary of central 

part of study area

Boundary of central 

part of study area Boundary of 

study area

"

"

"

"

"

"

!

!

!

RRW-3

RRW-4

RRW-2

RRW-1

RB-2

RB-1

111

+0.36

-3.07

-1.82

-7.41

-7.28

-9.18

-6.43

-0.71

-1.65 -1.17

-6.10

-1.77

+1.51

-1.67

-8.34

-5.35

-6.37

+1.00

+3.58

-7.68

-4.77

-5.99

-5.53 -8.39

-8.20

-5.63

-5.98

-6.21

-8.29

-9.65

-9.86

-3.66

-3.08

-0.82

+0.12

-3.95

-7.10

-2.53 -2.40

-0.90

-7.29

-8.44

-4.70

-4.65

-1.96

-2.65

-2.75

-0.65

+1.73

-1.08

-2.60

-7.00

-1.90

-1.15

-2.55

-6.94

-1.85

-8.70

-10.80

-14.50

-16.46

-14.99

-17.54

-14.15

-13.83

-13.18

-12.68

-17.11

-12.36

-15.99

-17.34

-15.02

-20.28

-15.22

-16.92

-11.87

-12.12 -10.52

-11.33

-14.09 -11.66

-11.28 -11.30

-12.00

-13.50 -13.17

-12.02

-18.27

-12.70

-13.36

-14.58

-10.62

-11.71

-10.07

-15.85

-13.86

-12.03 -10.90

-12.64

-16.85

-17.60

-15.83 -15.87

-7.12

-4.13

-6.31

-5.60

-14.92

-16.62

-16.66

-19.07

-19.09

-11.78

-13.95

-17.32

-18.71

"

-2.01

-4.07 -3.89 -1.88

-1.31

-6.73

-2.19 -6.77

-4.99

-9.52

-9.97

-4.53

-2.34 -0.87

-9.28 -9.06

-5.07

-1.17

-5.87

-6.70

-3.51

-1.73

-4.29

-6.53 -4.06

-5.36

-14.19

-11.71 -14.15

-14.90

-17.59

-19.52

-13.67

-5.61

-17.94

-16.59

-23.41

-13.64

97°37'30" 30' 97°22'30"

38°

37°52'30"

-10

Water-level measurements made by city of Wichita and

Equus Beds Groundwater Management District No. 2 personnel.

Change in storage volume in study area between August 1940 

and July 2008 is -134,000 acre-feet.

RRW-1

IW-12

-1.73

16

-14.99

EXPLANATION

Area of water-level decline:

 Less than 10 feet

 10 to less than 20 feet

 20 to less than 30 feet

Line of equal water-level change—

 Interval 2 feet. Dashed where

 approximately located. Hachures 

 indicate closed areas where the 

 water-level change is a smaller 

 decline than in the surrounding area

Phase 1 recharge site and identifier

Equus beds historic observation

 well—Well number shown above; 

 water-level change, in feet, shown 

 below

Well hydrograph shown in figure 2

Equus beds area index well—Well 

 identifier shown above; water-level 

 change, in feet, shown below

"

Figure 3. Water-level changes in the Equus Beds aquifer in the study area, August 1940 to July 2008.

Table 1. Storage-volume changes in Equus Beds aquifer near Wichita, 

south-central Kansas, August 1940 to July 2008.

[Data on file with U.S. Geological Survey, Lawrence, Kansas]

Time period

Storage-volume changes, in acre-feet

Study area Central part of 

study area

August 1940 to January 1993 1-255,000 1-154,000

August 1940 to July 2007 -123,000 -73,500

August 1940 to April 2008 -135,000 -75,600

August 1940 to July 2008 -134,000 -71,200

January 1993 to July 2008 +121,000 +82,800

July 2007 to July 2008 -11,000 +2,300

April 2008 to July 2008 +1,000 +4,400

1

 Storage-volume change previously reported by Aucott and Myers (1998).