WSP06521

• File Number: 8111.831
• Description: Arkansas River Compact Administration - Article VIII ‎(H)‎ Investigations
• Basin: Arkansas
• Date: 1/1/1985
• Author: David Pope
• Title: Supplement Report to ARCA Regarding Article VIII ‎(H)‎
• Water Supply Pro - Doc Type: Publication

While it is a fact that postcompact well development in

Colorado has occurred, additional analyses are required to
accurately determine the timing and extent of depletions
resulting from this groundwater usage. Without additional

analy~es, however, existing information and previous inves-
tigations by others would certainly lead a reasonable and
prudent engineer to consider well depletions to be a pos-

sible explanation for declines in streamflows. Colorado,

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however, presents no explanation for not considering well
depletions and fails to mention well development in its

report.

2. Return Flows from Transmountain Diversion

,
As noted in Kansas' first report, transmountain diver-

sions have significantly increased with time. A bar graph

of annual amounts of transmountain diversions into the

Arkansas River Basin is shown in the attached Figure 1.

Also attached is a single mass diagram of transmountain

diversions versus time (Figure 2). These graphs illustrate

the increase in transmountain diversions over time. The

large increases in the late 1960s and early 1970s reflect

the start of transmountain diversions 'from the Homestake and

the Fryingpan-Arkansas Projects. Transmountain diversions

are used for a variety of purposes, but most are either used

for municipal or irrigation purposes. Nearly all, if not

all, of the return flows from the initial use of these

transmountain diversions accrue to the streamflow of the

I Arkansas River above John Martin Reservoir.

This water is

not a natural inflow to the Arkansas River between the Canon

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