WSP03745

• File Number: 8111.815
• Description: Arkansas River Compact Administration
• Basin: Arkansas
• Date: 4/1/1990
• Author: UCACOE
• Title: Drought Contingency Plan - John Martin and Trinidad Lake - Appendix D
• Water Supply Pro - Doc Type: Publication

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SECTION IV - BASIN AND PROJECT DESCRIPTION.

4-01. Basin Description.

a. General. The Arkansas River above Great Bend, Kansas, shown in Plate
4-1, originates in central Colorado on the eastern face of the Rocky Mountains
near Leadville and flows southeast and east for a distance of 360 miles until
it crosses the state boundary with Kansas. The total drainage area above John
Martin Reservoir is 18,915 square miles, of which 785 square miles are
noncontributing. The Arkansas River Basin in Colorado comprises an area of about
25,410 square miles, of which about 1,708 square miles are noncontributing. The
Basin increases in width from about 25 miles in the headwaters area to a maximum
of about 140 miles in the vicinity of Las Animas, Colorado. The maj or
tributaries are described in the following paragraph.

b. Tributaries. Fountain Creek rises on the slopes of Pikes Peak and flows
generally south to join the Arkansas River at Pueblo. The St. Charles River
enters the Arkansas River from the south below Pueblo. Chico Creek enters the
Arkansas River from the north a few miles upstream from Avondale. The Huerfano
and Apishapa Rivers enter the Arkansas River from the south above La Junta,
Colorado. Horse Creek enters the Arkansas River from the north a few miles
upstream from Las Animas. The Purgatoire River, which is the largest tributary
above John Martin Dam, enters the Arkansas River at the head of the reservoir,
about 3 miles downstream from Las Animas. The principal tributaries in Colorado
below John Martin Dam are Big Sandy Creek, which enters from the north and Wolf
and Two Butte Creeks, which enter from the south. From Holly, Colorado, to Dodge
City, Kansas, a distance of about 140 miles, no large tributaries enter the main
stem. Throughout the reach from Holly, Colorado to Dodge City, Kansas the
contributing drainage areas average only 20 miles in width. Continuing
downstream, the largest tributaries in Kansas are Coon Creek, Pawnee River, and
Walnut Creek, all of which flow across the central prairies in a generally
eastward direction north of and approximately parallel to the main stem. They
enter the river successively from the north (left bank) as it makes the "great
bendll to the northeast. These Kansas tributaries are sluggish perennial streams
with flat gradients and broad flood plains in the lower reaches.

4-02. Proiect Description.

a. General. The Arkansas River Basin in Colorado contains two multipurpose
Corps of Engineers projects. John Martin Reservoir is located on the main stem
and Trinidad Lake is located on the Purgatoire River. There are also numerous
non Corps projects in the Basin. A description of Corps projects and a major
United States Bureau of Reclamation (USBR) project, in which the Corps has flood
control authority, are provided in the following paragraphs. Table 4 -1 describes
the general reservoir data along with pertinent elevations and current storage
volumes for each project. The average monthly and annual inflows at the projects
are presented in Plates 3-8 through 3-11. Other non-Corps projects, with
individual storage capacities of more than 20,000 acre-feet, are listed in Table
4-2.

4-1