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Coralville Lake Water Control Plan Update

The current Coralville Water Control Plan was approved in 2001. The Water Control Plans consist of operational parameters defining how, and when, water is stored and released. These include a schedule of releases, conservation pool levels to be maintained during non-flood or drought conditions and downstream water level constraints.

The following key issues inform the primary purpose and need of the Coralville Water Control Plan update:

  1. The Iowa River has experienced a significant increase in the magnitude and frequency of flooding.
  2. Sedimentation within the reservoir has negatively impacted available conservation (water supply)  storage capacity.
  3. Changes in land use and flood risk management infrastructure that effects nature/start of flood impacts (e.g., levees within the City of Coralville, changes to Dubuque Street, etc.).

The purpose of the study is to update the Coralville Water Control Plan to better meet mission objectives based on changes in flood frequencies, land use, and reservoir sedimentation. The District is drafting a feasibility report with an integrated environmental assessment to present a detailed account of the planning, regulatory and environmental considerations resulting in a Recommended Plan.


Current Plan:

Plan Information - Click on the image to view in a larger format.

Coralville Lake Growing Season   Coralville Lake Non-growing Season

Public Input

Comments about the Coralville Lake Water Control Plan Update may be directed to: or (309) 794-5704. The public comment period ends March 15.

Open House Schedule

Times and locations for the public open house events are as follows:

  • Tuesday, February 26, 2019

    Iowa State Extension Office, 317 Van Buren St., Wapello, IA 52653
    4-7 p.m. (Presentation at 5:30 p.m.)

  • Wednesday, February 27, 2019
    Iowa Public Library, 123 South Linn St., Iowa City, IA 52240
    4-7 p.m. (Presentation at 5:30 p.m.)

For those unable to attend a session in person, the presentations will be offered live on the Rock Island District’s Facebook page at starting at around 5:30 p.m. each day.