FLOOD08463

• County: Las Animas
• Community: Las Animas and Vicinity
• Stream Name: Arkansas River
• Basin: Arkansas
• Title: Arkansas River and Tributaries, Las Animas, Colorado, and Vicinity
• Date: 2/18/1964
• Prepared For: CWCB
• Prepared By: COE
• Floodplain - Doc Type: Project

cou I d be great I y. I ncreased by higher y i ~ Ids. These can be real I zed
through the use of supplemental Irrlgatilonwater,whlchwillbe-rilade
ava i I ab Ie by the, Fry i ngpan-Arkallsas ProUectandother Irnproverilents to
rei ieve water shortages on land now bei~g Irrigated, and fromgeins In
farm technology. Net farm inoome has ~een projeoted to Inorease.at a
rate of, 0.7' percent compounded annua II yfrom 1960 to 2060, orebout
2.08 times the present net Income. .

63. Population and farm income c~anges are the mostsignlfiCl!int
factors wh Ich are expected to have othEirthan mi nor effectoh.-the
economy of the Las An i mas area over th~ next century. Anaverege~t
the population and agricultural growthifactors of 1.7, orO.5perctl'!t
compounded annually, Is considered realistic for future growth Lhfhe
Las Animas area.

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64. FLOOD HISTORY.- The primary flood threat to l.asAnlml!is~~d
vicinity Is overflow from the Arkansas,Hiver. Portions of the aree
are subject to flooding from very high, f lows on the Purgatoire Rivet; .
but the damagas on an average annua I b~s I s are not sign I f Icent. . In;~
add I t I on to urban deve I opment, va I uab I~farm I and surround I rig l.aIH\t\(rnes
I s subject to flood i ng. The aggrad i ngi rl verbed wh loh charecter izestl'he
Arkansas River from Pueb 10 to John Marrt I n Dam has progress I ve Iyrell~~ed
the channel capacity at l.as Animas to ;the point that Overbank flow.q~n
be expected at about 6,500c.f .s. Flooding of the urban areabegrn~;
at a discharge of 10,000 c.f.s.

65. Historical accounts Inc lude ireferences to several majorfldods
in the vicinity of Las Animas prior tq the period of rei iable rec9rd~i
The ear I i est known flood occurred in 1826, before permanent settlement
of the Arkansas River Valley, and was ,reported to have Inundatedth!i>
bottom I ands near the present I ocat i 01. of l.as An I mas to a depth ;of'
15 feat. Another major flood occurrel;! In June 1864. Durlng;,May';Ji.lne
1867, flooding was so extensive that ~t. Lyon was forced toreloceite
17 miles farther west. Large magnitude floods also were reported In
Ju Iy 1886 and May 1894. .

66. The largest flood for which! rei lable data are available
occurred during June 1921 . According: toU.S . Weather Bureau records ,
the 48-hour ra I nfa II over the Arkensa~ Ri ver watershed betweenCa?lon
City and Pueb loon June 3-4 was 3 to;S Inches. The peak d i scherge,on
the Arkansas River at Pueblo was 103,,000 c.f.s. which, as thefloop.
progressed downstream, increased to 200,000 c.f.s. at La Junta. 1here
was very I i tt Ie tr Ibutary I nf low be low La Junta and va II ey storage-
reduced the peak to 187,000 c. f . s. by the t I me it reaChed l.as An i.mlils.
According to local residents, almost ithe entire city was floodedlilnd
the water was 4 to 5 feet deep in son)e places. The Barrier Dam which
was bul 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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