US Army Corps of Engineers
Rock Island District Website

Coralville Lake Water Control Plan Update

Click here to view the Coralville Lake Water Control Plan Update overview presentationThe U.S. Army Corps of Engineers Rock Island District is finalizing the Coralville Lake Water Control Plan and is seeking public input.

Click here to review the Draft Feasibility Report with Integrated Environmental Assessment

A video presentation outlining the plan changes can be viewed by clicking on the image to the right. 

Comments regarding this plan my be submitted through March 19, 2021, by clicking the following link: Submit Comment

Comments will also be accepted via email to:, telephone to: 309-794-5704, or by mail to: Rock Island District, Attn: PM-M, P.O. Box 2004, Rock Island, IL 61204-2004

Virtual Public Open House Information

Two virtual open house events will be hosted to offer a question and answer opportunity for the public and gather feedback about the updated plan. The first virtual event will be held Thursday, Feb. 25, at 5 p.m. and the second will be Thursday, March 4, at 5 p.m. The event will be hosted online at the following link:
An audio-only option is also available by dialing 1-844-800-2712 then entering the meeting number 199 338 6849. When prompted to enter an attendee ID, enter #. 

Update Process

The current Water Control Plan for Coralville Lake was approved in 2001. These plans consist of operational parameters defining how, and when, water is stored and released from the reservoir. This includes 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 were the primary purpose for updating Coralville Lake's Water Control Plan:

  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.).

As part of the plan update process, a feasibility study was conducted to identify ways to better meet mission objectives based on changes in flood frequencies, land use, and reservoir sedimentation. A draft feasibility report with integrated environmental assessment was produced as a result of this study and provides a detailed account of planning, regulatory and environmental considerations. Following public review of the draft feasibility report, a recommended plan will be send to the Mississippi Valley Division for final approval. 


Current Plan:

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

Coralville Lake Growing Season   Coralville Lake Non-growing Season

Scoping Meeting Presentations

Points of Contact

Questions about the Coralville Lake Water Control Plan Update may be directed to: or (309) 794-5704.