WSP03823

• File Number: 8135.300
• Description: Ditch Companies - Catlin
• State: CO
• Basin: Arkansas
• Water Division: 2
• Date: 1/29/1976
• Author: D Helton R McCabe
• Title: Catlin Transfer Plan and John Martin Permanent Pool Operation
• Water Supply Pro - Doc Type: Report/Study

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BACKGROUND

John Martin Reservoir (Figure 1) was authorized by the Flood
.Control Act of 1936 for the official purposes of flood control
and conservation of irrigation water. Construction was begun
by the U.S. Army Corps of Engineers in 1939; but, because of
World War II, it was not completed until 1948. According to
the most recent area-capacity table, the reservoir's capacity
is 621,000 acre-feet at maximum elevation, of which 351,000
acre-feet is conservation storage for irrigation. Water stored
in the reservoir's flood control space, except for 10,000 acre-
feet of proposed permanent pool, .must be released as rapidly
as possible at maximum practical rates.

Although the official project purposes were flood control and
irrigation, these were not its real purposes. John Martin
Reservoir was constructed because it provided the means of
ending 50 years of litigation between the States of Colorado
and Kansas through adoption of the Arkansas River Compact.

The Arkansas River Compact (Appendix A) apportions the waters
of the Arkansas River by prescribing the operation of John
Martin Reservoir. The operation is based on a compact year,
which begins on November 1 and ends the following October 31.
During the winter storage season, November 1 through March 31,
all water entering the reservoir is stored except that Colo-
rado irrigators can demand releases of river flow into the
reservoir, limited to 100 cubic feet per second (cfs). During
the summer storage period, flood waters entering the reservoir
are stored except that Colorado water users can demand releases
of river flow, limited to 500 cfs, and Kansas water users can
demand releases equivalent to that portion of the river flow
between 500 cfs and 750 cfs. Releases of stored water can be
made during the summer storage period at maximum rates of
750 cfs for Colorado water users and 500 cfs for Kansas water
users. Storage water release rates are reduced to 600 cfs
for Colorado and 400 cfs for Kansas when the conservation
storage is less than 20,000 acre-feet. Thus, maximum release
rates permitted during the irrigation season are a combination
of river flow and available stored water. "River flow" is
defined as the sum of the flows of the Arkansas and Purga-
toire Rivers measured at U.S. Geological Survey (USGS) gaging
stations located upstream from John Martin Reservoir. As long
as water is stored in the reservoir, Colorado is not permitted
to administer diversions on a normal priority basis since Colo-
rado water users below the reservoir in Water District 67

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