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:
- The Iowa River has experienced a significant increase in the magnitude and frequency of flooding.
- Sedimentation within the reservoir has negatively impacted available conservation (water supply) storage capacity.
- 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.