WSP00415

• File Number: 8103
• Description: Arkansas river Basin Legislation
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 1/31/1968
• Author: W W Wheeler and Asso
• Title: Coordinator of Natural Resources - State of Colorado - Exhibits on Water Legislation Investigations for the Arkansas River Basin - Volume IV --January 31 1968
• Water Supply Pro - Doc Type: Report/Study

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GROUND WATER AQUIFER

In order to fully Integrate the ground and surface water

supply of the Arkansas Valley, It is necessary to have an under-

standing of the aquifer. The Arkansas River alluvium between

Pueblo and the Colorado-Kansas line consists of approximately

310,000 acres of which 208,000 acres are upstream from John Martin

Reservoir. Average saturated thickness above the reservoir Is

approximately 22 feet and 34 feet downstream from the reservoir.

It is estimated there is approximately 1,860,000 acre-feet of water

in the saturated alluvium between Pueblo and the state line which

is divided almost equally between the area upstream of the reservoir

and that below. However, probably not over 50 percent of this supply

Is economically recoverable under normal conditions. The U. S.

Geological Survey has estimated ground water underflow at the

Colorado-Kansas line at 7,000 to 10,000 acre-feet per year.

The ground water aquifer of the Arkansas Valley can almost

be considered as two different basins. Near the John Martin

Reservoir site, the Dakota sandstone outcrop causes most of the

ground water flow to come to the surface as a flowing stream. There

Is little alluvium for a ground water flow to take place. However,

this flow is not lost. It helps satisfy downstream senior rights

that would normally place a call on upstream junior priorities or

increases storage In John Martin Reservoir when it is under

Colorado-Kansas Compact jurisdiction.

It Is possible that future investigation may reveal the

desirability of establishing batteries of pumps in the alluvium

near the state line to relieve some of the demand by Kansas under

the Compact from John Martin Reservoir. Water would be borrowed

from the aquifer and replenished by normal surface and subsurface

flows. This would result in an additional equivalent amount of

water available to Colorado users both upstream and downstream from

the Reservoir, since no demand would be placed on upstream junior

priorities by downstream seniors so long as there was water Impounded

in John Martin Reservoir.

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