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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the effectiveness or justification of the potential major drainage and
flood control project. Therefore, the plan was developed in detal I to
provide flood protection at Las Animas.

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81. PROJECT FORMULATION.- The local protection project at Las
Animas was further analyzed to insure that each separable segment
would provide benefits at least equal to Its cost, that the scale of
development would be such as to provide the maximum net benefits, and
that there are no more ,economical means of accomplishing the same
purpOse which would be precluded from development If the project were
undertaken.

82. Many alternatives were examined including a sma I I ring levee
around Las Animas and long levees on both banks of the Arkansas and
Purgatoire Rivers. Practically all of the property on the left bank
of the Arkansas River that would suffer damage from inundation Is
above'the stage of even the most severe flood that can be expected .
Flooding from the Purgatoire River does not cause problems' serious
enough to warrent levee protection. The greatest concentrati'on of
damages occur's with I n the city of Las An I masi nd i cat i ng that the
nucleus for project formulation purposes would be a small ring levee
to protect only the urban property. Costs and benefits of the most'
practicable plan to accomplish this purpose, designated as Plan A,
were estimated as wel I as the costs and benefits of two other plans
of greater scope, designated as Plans Band C. The three plans ere
depicted on plate 2 and a chart comparing the annual charges and bene-
fits is exhibited on plate 3.

83. 'In addition to the urban area, a small portion of the sur- '
rounding agricultural area would be protected by Plan A. 8ecauseof
topographic and other considerations, such a plan would be less costly
than a ring levee to protect only the city. Plans ,8 and C also would
'afford protection to the city and, in addition, protect more of the
agricultural area. The right bank levee of Plan C would encompassj
practically all of the irrigated land south of the Arkansas River In
the vicinity of Las Animas. A desirable feature of this plan is that
the upstream end of the levee could be tied back to high ground with
the taking of very little irrigated farmland. The right bank levee
for Plan 8 was designated to take advantage of a slight ridge for the
upper tie-back section of the levee and is the most economical plan
for an Intermediate scope of protection. Its principal advantage is
that the rai Iroad grade at the upper Junction with high ground would
not have to be raised as much as with either of the other two plans.
The right bank levee tie-back section at the lower end, near the
railroad, would be the same for all three plans. Consideration was
given to extending the levee about two mi les farther in a southwest
direction to high ground near Boggsvi I Ie; however, it was determined
that this would be infeasible mainly because of the complicated
interior drainage problems.

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