FLOOD04360

• County: Bent
• Community: Las Animas
• Stream Name: Arkansas River
• Basin: Arkansas
• Title: Interim Report on Review Survey for Flood Control
• Date: 8/1/1963
• Prepared For: Las Animas
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Floodplain Report/Masterplan

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could be greatly increased by higher yields. These can be real ized
through the use of supplemental irrigation water, which wi I I be made
avai lable by the Fryingpan-Arkansas Project and other improvements to
rei ieve water shortages on land now being irrigated, and from gains in
farm technology. Net farm income has been projected to increase at a
rate of 0.7 percent compounded annually from 1960 to 2060, or about
2.08 times the present net income.

63. Population and farm income changes are the most significant
factors which are expected to have other than minor effect on the
economy of the Las Animas area over the next century. An average of
the population and agricultural growth factors of 1.7, or 0.5 percent
compounded annually, is considered realistic for future growth in the
Las Animas area.

64. FLOOD HISTORY.- The primary flood threat to Las Animas and
vicinity is overflow from the Arkansas River. Portions of the area
are subject to flooding from very high flows on the Purgatoire River;
but the damages on an average annual basis are not significant. In
addition to urban development, valuable farmland surrounding Las Animas
is subject to flooding. The aggrading riverbed which characterizes the
Arkansas River from Pueblo to John Martin Dam has progressively reduced
the channel capacity at Las Animas to the point that overbank flow can
be expected at about 6,500 c.f.s. Flooding of the urban area begins
at a discharge of 10,000 c.f.s.

65. Historical accounts include references to several major floods
in the vicinity of Las Animas prior to the period of rei iable records.
The earliest known flood occurred in 1826, before permanent settlement
of the Arkansas River Val ley, and was reported to have inundated the
bottom lands near the present location of Las Animas to a depth of
15 feet. Another major flood occurred in June 1864. During May-June
1867, flooding was so extensive that Ft. Lyon was forced to relocate
17 mi les farther west. Large magnitude floods also were reported in
July 1886 and May 1894.

66. The largest flood for which rei iable data are avai lable
occurred during June 1921. According to U.S. Weather Bureau records,
the 48-hour rainfal lover the Arkansas River watershed between CaNon
City and Pueblo on June 3-4 was 3 to 5 inches. The peak discharge on
the Arkansas River at Pueblo was 103,000 c.f.s. which, as the flood
progressed downstream, increased to 200,000 c.f.s. at La Junta. There
was very I ittle tributary inflow below La Junta and val ley storage
reduced the peak to 187,000 c.f.s. by the time it reached Las Animas.
According to local residents, almost the entire city was flooded and
the water was 4 to 5 feet deep in some places. The Barrier Dam which
was bui It shortly after this flood would have reduced the peak dis-
charge from 187,000 c.f.s. to about 140,000 c.f.s. The authorized
Pueblo Dam would have reduced it to 108,000 c.f.s.

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