Coralville Lake Water Control Plan

The new Water Control Plan for Coralville Lake was approved March 2022. The plan consists 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 storage capacity.
  3. Changes in land use and flood risk management infrastructure that effects the nature/start of flood impacts (e.g., levees within the City of Coralville, changes to Dubuque Street, etc.).
  4. Several deviations from the previous water control plan that were approved and conducted over the years have demonstrated the need and viability of the changes to the plan.

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 final feasibility report with integrated environmental assessment was produced as part of this study and provides a detailed account of the planning, regulatory, and environmental considerations.  The feasibility report and appendices are linked under the Project Documents section of this webpage, along with the Coralville Lake Standing Instructions which include the regulation tables for the updated water control plan.  The district began operating under the new plan in March 2022.

Point of Contact

Questions about the Coralville Lake Water Control Plan may be directed to: or (319) 338-3543 ext. 6300.

Water Control Plan Documents