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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'0155
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season the water of the Arkansas River at Lamar averaged 5 tons of

dissolved solids per acre-foot. Under normal Irrigation applications

for alfalfa, this would be the equivalent of almost 10 tons of salt

per Irrigation season.

A large portion of the lands downstream from John Martin

Reservoir would Ideally require at least 50 percent of the appl led

Irrigation water to be leached through the root zone to avoid excessive

salt accumulations. This is the equivalent of a surface application

of almost 4 acre-feet of water per acre.

Unless provision Is made for leaching of salts from the

root zone with lesser concentrated water which would probably have

to be derived from natural runoff, releases from John Martin Reservoir,

the use and reuse of local waters could ultimately result in the loss

of the lower Arkansas Valley to Irrigation agriculture. We are

presently analyzing procedures whereby this economy can be sustained;

and which will still provide for the best uti! ization of the waters of

the Arkansas River upstream from John Martin Reservoir. (See Exhibit

for salt concentrations, aquifer pumping capability and irrigated

land downstream from John Martin Reservoir).

It may be desirable to operate the river downstream from

La Junta according to past practices up to the period in time when

the Amity Canal is no longer entitled to divert under Its priority

of 283 cfs. After this time, the remainder of the senior operational

rights downstream from La Junta could probably be satisfied to the end

of the Irrigation season from the ground water aquifer or return flow.

This, In theory, would provide the required leaching and also permit

the fullest utilization of the ground water aquifer and surface return

flows that are lost by Colorado to Kansas, The aquifer of the lower

Arkansas Valley under lands irrigated by the Amity Canal Is inadequate

to supply the prlnlclpal priority of the canal.

OVER-IRRIGATION

There are only a very limited number of ditches In the

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