FLOOD10655 ‎(2)‎

• County: Chaffee
• Community: Salida
• Title: FIS - Salida
• Date: 9/30/1982
• Prepared For: Salida
• Prepared By: FEMA
• Floodplain - Doc Type: Current FEMA Regulatory Floodplain Information

Flooding problems within the City of Salida are aggravated by the
restriction of drainage channels due to vegetation growth and
accumulated debris.

2.4 Flood Protection Measures

The City of Salida has no existing regulations or ordinances con-
cerning flood management or protection measures. There is very
little flood protection for the City of Salida. The main protection
frcm the South Arkansas River is from a bl uff on the north edge of
the r;ver~ This protects the City from more frequent floods.

3.0 ENGINEERING METHODS

For f1 oodi ng sources stud; ed in deta il in the communi ty, standard hydro-
logic and hydraulic study methods were used to determine the flood
hazard data required for this study. Flood events of the magnitude which
are expected to be equalled or exceeded once on the average during any 10-,
50-, 100-, and 500-year floods, have a -nr:-2, 1, and 0.2 percent chance,
respectively, of being equalled or exceeded during any year. Although the
recurrence interval represents the , on9 term average peri od between fl oads
of a specific magnitude, rare floods could occur at short intervals or even
within the same yearo The risk of experiencing a rare flood increases when
periods greater than 1 year are considered. For example, the risk of
having a flood which equals or exceeds the IOO-year flood (1 percent chance
of annual occurrence) in any 50-year period ;s approximately 40 percent
(4 in 10), and, for any 90-year period, the risk increases to approximately
. 60 percent (6 in 10). The anal yses reported here refl ect fl oodi ng poten-
tials based on conditions existing in the county at the time of completion
of this study. Maps and flood elevations will be amended periodically to
reflect future changes.

3.1 Hydrologic Analyses

Hydrologic analyses were carried out to establish the peak discharge-
frequency relationships for floods of the selected recurrence inter-
vals for each stream studied in detail and to compare with results of
previous studies for the flooding sources studied here.

Peak di scharges for the vari OUS recurrence interval s for the South
Arkansas River were taken from data prepared by eWeB for the Arkansas
River Basin at Salida, Colorado (Reference 1).

Streamflow data from 11 measuring stations located within the Upper
Arkansas River Basin was used in this analysis. This data is con-
tained in U.S. Geological Survey Water Supply Papers for the Arkansas
River Basin (Reference 3 and 4).

The peak flow figures for each frequency used in the hydraulic
anal ysi s of thi s study were estimated us; ng a Reg; anal Log-Pearson
Type III Analysis (including the 1957 data point). The 1957 peak

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