Ground-Water Model and Pumping Scenarios for the Middle Arkansas River Subbasin

Ground-Water Model and
Pumping Scenarios for the
Middle Arkansas River Subbasin
Don Whittemore, Marios Sophocleous,
Jim Butler, Brownie Wilson, Xiaoyong Zhan,
Dave Young, Mike McGlashan
Kansas Geological Survey
and Ming-Shu Tsou
HydroGeoLogic Inc.
Funded in part by the
Division of Water Resources, Kansas Department of Agriculture
and the Kansas Water Office
Model grid
boundary
Middle Arkansas
Subbasin
A
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Active model area
Kansas Geological Survey
HYDROLOGIC RESPONSES TO CHANGES IN AND
OUTSIDE OF SUBBASIN
• Ground-water levels have declined in the Middle Arkansas
subbasin in response to consumptive pumping from the alluvial
and High Plains aquifers.
• Water-level declines have decreased the discharge of ground
water into the Arkansas River. Where water levels have declined
below the bottom of the river bed, river water seeps into the
underlying aquifer rather than flowing downstream. As a result,
river flows have decreased and a dry river bed has been present
over much of the subbasin during the last few years.
• Long-term declines in the flow of the Arkansas River from
southwest Kansas and of the Pawnee River into the subbasin
have contributed to decreases in Arkansas River flow in the
subbasin.
Kansas Geological Survey
WATER-QUALITY RESPONSES TO CHANGES IN AND
OUTSIDE SUBBASIN
• Long-term increases in the salinity of Arkansas River water from
Colorado have increased the salinity of high flows that enter the
Middle Arkansas subbasin.
• The salinity of ground water in the Arkansas River valley in the
subbasin increases when inflow passing through southwest
Kansas from Colorado seeps into the aquifer underlying the river.
The saline ground water is moving outward from the river in
response to ground-water level declines.
• Long-term decreases in Pawnee River flow have decreased the
amount of freshwater flow entering the Arkansas River in the
subbasin at Larned.
Kansas Geological Survey
Hydrographs of Wells in Edwards County within CREP Area
Well 374954099270701, Edwards Co., Arkansas R. valley
Well 375801099191001, Edwards Co., near river valley
2135
Water-level elevation, feet
Water-level elevation, feet
2220
2215
2210
2205
2200
2195
2190
1/1/70
1/1/75
1/1/80
1/1/85
1/1/90
1/1/95
1/1/00
2130
2125
2120
2115
2110
2105
1/1/70
1/1/05
Well 375550099175601, Edwards Co., away from valley
1/1/85
1/1/90
1/1/95
1/1/00
1/1/05
2080
Water-level elevation, feet
Water-level elevation, feet
1/1/80
Well 375847099081601, Edwards Co., away from valley
2145
2140
2135
2130
2125
2120
2115
1/1/70
1/1/75
1/1/75
1/1/80
1/1/85
1/1/90
1/1/95
1/1/00
1/1/05
2075
2070
2065
2060
2055
2050
1/1/70
1/1/75
1/1/80
1/1/85
1/1/90
1/1/95
1/1/00
1/1/05
Kansas Geological Survey
Mean annual flow, ft3/sec
1000
100
10
1
0.1
Measured Flow at USGS Gages
Arkansas River near Kinsley
Arkansas River near Larned
0.01
1970
1975
1980
1985
1990
1995
2000
2005
Kansas Geological Survey
Kansas Geological Survey
Kansas Geological Survey
WHAT DOES THE GROUND-WATER FLOW MODEL DO?
Mathematically simulates ground-water flow and stream-aquifer
interactions in the Middle Arkansas subbasin for 1944-2004
and future scenarios
Components of the model include:
Areal precipitation recharge
Stream inflow to the model area
Ground-water flow into, within, and out of model area
Ground-water flow to streams and leakage of water from
streams and canals to ground water
Pumping of ground water
Recharge of applied irrigation water to ground water
Loss of water from evapotranspiration
Kansas Geological Survey
Model grid
boundary
Middle Arkansas
Subbasin
A
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Active model area
Kansas Geological Survey
Kansas Geological Survey
Kansas Geological Survey
5
Kansas Geological Survey
Cumulative Net Aquifer Storage and Streamflow Gains
2,000,000
Cumulative value in acre-feet
1,500,000
Net aquifer storage gain
Net streamflow gain
1,000,000
500,000
0
-500,000
-1,000,000
-1,500,000
-2,000,000
1940
1950
1960
1970
1980
1990
2000
Net aquifer storage gain = storage accumulation minus storage depletion
Net streamflow gain = stream gain from ground water minus stream loss to ground water
Kansas Geological Survey
MODEL SCENARIOS
Sensitivity to increased stream inflows during 1980-2004
Future pumping during 50 years, 2005-2054
Pumping at current levels
No pumping
Reduction of 24% of pumping in CREP areas
Equivalent to 14.5% reduction in model area
Reduction of 25,287 acre-ft/yr in net pumpage
Retirement of Circle K Ranch water rights
Kansas Geological Survey
Cumulative Net Aquifer Storage and Streamflow Gains
4,000,000
Net streamflow gain
Net aquifer storage gain
Cumulative value in acre-feet
3,000,000
2,000,000
1,000,000
0
-1,000,000
-2,000,000
-3,000,000
-4,000,000
1940
1960
1980
2000
2020
2040
2060
Scenario: Continued Pumping at Current Levels
Kansas Geological Survey
Kansas Geological Survey
Comparison of Saturated Thickness Observed in 2005
and Simulated for the Continued Pumping Scenario for 2054
Kansas Geological Survey
Cumulative Net Aquifer Storage and Streamflow Gains
4,000,000
Cumulative value in acre-feet
3,000,000
Net streamflow gain
Net aquifer storage gain
2,000,000
1,000,000
0
-1,000,000
-2,000,000
-3,000,000
-4,000,000
1940
1960
1980
2000
2020
2040
2060
Scenario: No Pumping
Kansas Geological Survey
Location of CREP Area
(shaded green)
within Model Area
Cumulative Net Aquifer Storage and Streamflow Gains
4,000,000
Cumulative value in acre-ft
3,000,000
2,000,000
Net streamflow gain - CREP pumping
Net streamflow gain - continued pumping
Net storage gain - CREP pumping
Net storage gain - continued pumping
1,000,000
0
-1,000,000
-2,000,000
-3,000,000
-4,000,000
1940
1960
1980
2000
2020
2040
2060
Comparison of CREP Pumping and Continued Pumping Scenarios
Kansas Geological Survey
Comparison of CREP Pumping and Continued Pumping Scenarios
Kansas Geological Survey
80
Great Bend gage
Dundee diversion
100
Larned gage
2000 Base run
2050 CREP pumping
2050 Continued pumping
120
Pawnee River
Flow for wet year with substantial Arkansas River inflow
0
20
Coon Creek
20
Kinsley gage
40
Walnut Creek
60
Circle K Ranch
Mean annual streamflow, ft3/sec
140
40
60
80
100
Arkansas River mile
Kansas Geological Survey
HYDROLOGIC AND SALINITY RESPONSES TO FUTURE
CHANGES IN THE ARKANSAS RIVER CORRIDOR
• Ground-water levels will continue to decline in the Middle Arkansas
subbasin unless there are substantial reductions in consumptive
pumping.
• Continuing water-level declines will increase the seepage rate of high
flows in the Arkansas River from southwest Kansas (when they occur)
into the alluvial aquifer and underlying High Plains aquifer. This will
decrease the amount of river flow reaching the Lower Arkansas basin
for a similar, past high flow entering the subbasin. More saline water
from high Arkansas River inflows will enter the alluvial and High
Plains aquifers.
• Continuing water-level declines will increase the movement of saline
ground water in the aquifer outward from the river valley.
• Continuing decreases in Pawnee River flow will decrease the amount
of freshwater flow entering the Arkansas River at Larned.
Kansas Geological Survey
Water resources
future
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