FLOOD07698

• County: Statewide
• Community: Rock Rapids, Iowa
• Basin: Statewide
• Title: Problem Identification Report Rock River at Rock Rapids Reconnaissance Study Section 205
• Date: 4/1/1995
• Prepared For: US Army Corps of Engineers
• Prepared By: Greenhorne & O'Mara, Inc.
• Floodplain - Doc Type: Project

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The existing conditions flood profiles for those events are presented in
figure 3. The 100-year water surface elevations computed from the
revised model are similar to the FIS values. The flood boundaries shown
in the FIS report were used for the existing conditions flood boundaries
for this study. As determined from the flood damage analysis described
later in this report, the point of initial flooding of structures occurs
at about the 50-year event.

Table 3
Existing Conditions Vater Surface Elevations
ROCK RIVER FIS VATER SURFACE ELEVATIONS Ifeet)
STATION CROSS-SECTION 10-YR 50-YR 100-YR 500-YR
210,059 A 1322.S 132S.8 1327.7 1331.4
210,244 B 1322.7 1326.3 1328.7 1333.7
21S,64S C 1325.6 1329.2 1331. 0 133S.7
218,926 D 1328.4 1332.0 1333.5 1339.0
224,737 E 133S.S 1339.3 1340.6 1344.3
22S,187 F 1336.0 1340.6 1342.4 1346.5
22S,840 G 1337.0 1341.7 1343.4 1347.8
226,000 H 1337.0 1342.0 1343.8 1348.6
227,380 I 1339.0 1342.4 1344.4 1349.6
FLOOD DAMAGE ANALYSIS

GENERAL

The flood damage analysis for Rock Rapids was performed using the

Omaha District's current version of the Ark flood damage model called

Newark4. Existing conditions water surface profiles, as described

previously, were used in the flood damage model to assess the extent of

flood damages within the city. Total flood damages determined for this

analysis include damages to structures, contents, and residential

appurtenances. Damages to public features such as roadways, utilities,

and bridges as well as cleanup costs were also included. Flood plain

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