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

,

TABLE 2. -- Estimated Flood Frequencies -
Arkansas River at Las Animas, Colorado

Frequency of
Occurrence
in Years

Maximum Annual
Discharqe (c.t.s.)*
Existing Pueblo Dam
Conditions Operatinq

2
5
10
25
50
100
200
400
600

7,700
19,000
31,000
54,000
75,000
104,000
143,000
194,000
285,000

6,700
16,000
26,000
44,000
59,000
81,000
110,000
145,000
205,000

* Present channel capacity at Las
Animas is 6,500 c.f.s.

71. In order to establish criteria for analyzing the flood pos-
sibi I ities at Las Animas and the degree of protection to be afforded,
an estimate was made of the flood which might be expected to occur as
the result of the most severe combination of rainfal I and runoff con-
ditions characteristic of the region. This large magnitude flood of
infrequent occurrence is des i gnated as the "standard project flood."
The standard project flood study for Las Animas involved the trans-
position of the 1921 storm to a more critical location west of the
city and computation of the flood discharges which would occur as the
result of such a storm. The standard project flood thus determined
has a peak discharge of 200,000 c.f.s. at Las Animas and a volume of
452,000 acre-feet.

.

72. The area subject to flooding at and in the vicinity of Las
Animas, for which protection is recommended, is about 8.0 mi les long
from east to west with a maximum width of 2.5 mi les at Las Animas.
The area includes about 6,880 acres comprising 740 acres classified
as urban and suburban, 4,170 acres of irrigated farmland, 1,110 acres
of dry farm and grazing land, and 860 acres of waste land and trans-
portati on rights-of -way. Transportat i on fac i lit i es I nc I ude the depot
and 9 miles of the main line of the AT~SF Rai Iway System, 8 miles of
U.S. Highway 50, State Highways 101 and 194, city streets, county
roads, and a sma I 1 airport. Urban improvements include about 1,050
residential units, 150 business units located mostly in the main
business district, schools, churches, publ ic bui Idings, and uti I ity
plants. Most of the business property would be flooded to a depth
greater than 3 feet. The newer, high-value residential property is

22