FLOOD11630 ‎(2)‎

• County: Statewide
• Basin: Arkansas
• Title: Post Flood Assessment Report - Arkansas River
• Date: 9/15/1999
• Floodplain - Doc Type: Flood Documentation Report

Because the levee was an incidental feature, no attempt was made to eactend and tie the levee
back to high ground on the upstream (western) end. The recommended plan in the Draft General
Design Memorandum of January 1986 for the La Junta, Colorado Local Protection Project called
for a levee that follows the general alignment of the existing levee with the exception that it
would be tied back to higher ground just west of West Avenue. The existing levee Iacks this
closure and therefore is at risk of being flanked by the river. Local officials have indicated a
desire to extend the existing levee to reduce the possibility of this occurring.
AREAS AND PROPERTIES AT RISK
Fountain Creek and Tributaries
Following the 30 April 1999 flood event teams of engineers were dispatched to inspect the areas
damaged and assess applicability of Corps of Engineers disaster assistance programs. A list of
problem areas was tabulated for the Fountain Creek and its tributaries (see Attachment 1).
Arkansas River
Rocky Ford: The City of Rocky Ford will continue to be subject to flooding as a result of the
irrigation ditches that intercept the flow of several local arroyos. The irrigation ditches do not
have by-pass features and so the combined flow overwhelms the capacity of the ditches. Local
o~cials were concerned that these overflows would breach the sewage treatrnent ponds and
create a health hazard. During the Apri129, 1999 event sewer lines in the area were backed up
and did create a health hazard for those using wells for domestic water supply.
La Junta: The North La Junta area, being about 20 feet lower in elevation than the La Junta area
to the south, will be primarily at risk during any future flood event. It is still unclear as to the
sequence of events; however, the westem portion of North La Junta (La Junta Gardens) may
have first experienced flooding from overtopping or a breach in the Fart Lyons Imgation Canal.
If this is the case, then it is possible that this area is at risk of flooding from more frequent events
than the Apri129, 1999 flood which overtopped the Corps of Engineers levee on north bank of
the Arkansas River. Due to the possibility that the Corps of Engineers levee could be flanked at
the upstream end by a larger flood, the La 3unta Gardens area is at risk for future flooding. A
cursory floodplain analysis for a 50-year event indicated flood depths would vary from 0.7 foot
to 4.8 feet. Based on the damage sustained by the Apri129, 1999 flood, the existing levee, once
restored, will provide protection up to the 8-year event. At risk of damage from a larger event
are 421 homes, 20 businesses, 1 public structure, and 57 barns, detached garages, and sheds.
Residential structures and contents have an estimated value of $4,979,000; commercial structures
and contents have an estimated value of $676,000; public structures and contents have an
estimated value of $33,000; and outbuilding structure and contents have an estimated value of
$622,000.
Downstream of John Martin Dam: Currently the operations manual for the dam does not allow
Post Flood Assessment Report 39
Chapter S- Flood Risk Assessment
Draft Revfsed 09/09/99