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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serving Rock Rapids is U.S. Highway 75, while the primary east-west
highway is State Highway 9. A vicinity map of the Rock Rapids area was
previously presented in figure 1.

EXISTING IMPROVEMENTS

Rock Rapids has an existing levee on the north side of the city

which extends along the right bank of Koon Creek and the Rock River in the

vicinity of their confluence. The levee was constructed during 1969 as

a result of flooding damage which occurred during that same year. The

levee essentially runs along the north side of the Island Park area,

varies in height, and is vegetated with grass, brush, and trees. The

construction and maintenance of the levee area were not in accordance with

Corps of Engineers' specifications, leaving the structural integrity of

this levee questionable. There is a private ring levee along the left

bank of the Rock River that protects an individual residential structure

near East Street. Fill material and sand bags were placed in various

locations within the city during the 1993 flooding events. Continuous

flood protection does not exist for the city.

FLOOD HISTORY

A relatively small percentage of Rock Rapids lies within the Rock
River flood plain. Several floods have been documented on the Rock River;
however, very little statistical information is available for the Rock
River basin prior to the year 1948 when a stream gaging station was
established at Rock Valley, Iowa, which is approximately 20 miles
downstream of Rock Rapids. A USGS stream gaging station was in operation
at Rock Rapids from 1960 to 1974. The maximum flood of record was
considered to be the flood of April 1969 until major flooding occurred
in Kay and July of 1993. Available information on relevant Rock River
flood events is summarized below.

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