US Army Corps of Engineers
Rock Island District

Civil Works Public Notices

Des Moines River Basin Master Reservoir Regulation Manual

Published July 3, 2018

Public Comment Request

The US Army Corps of Engineers, Rock Island District (District) requests your review of the proposed Des Moines River Basin Master Reservoir Regulation Manual update. Please click on http://go.usa.gov/xQSF9 to view the report and appendices.

The purpose of the study is to update the Des Moines River Basin Master Reservoir Regulation Manual to better meet mission objectives based on changes in flood frequencies, land use, and reservoir sedimentation. The recommended plan would result in a revised Des Moines River Basin Master Reservoir Regulation Manual, which includes the Saylorville Lake and Lake Red Rock Water Control Plans. The District drafted this feasibility report with an integrated environmental assessment to present a detailed account of the planning, regulatory and environmental considerations resulting in the Recommended Plan.

To request a paper copy or CD, contact Mr. Jim Homann of our Programs and Project Management Division, 309/794-5704, email: CEMVR_Planning@usace.army.mil, or by writing to our address:

US Army Engineer District, Rock Island
 Corps of Engineers, ATTN: Jim Homann
 Clock Tower Building – PO Box 2004
 Rock Island, IL 61204-2004

Please furnish your comments no later than August 17, 2018, to Mr. Homann of our Programs and Project Management Division, 309/794-5704, email: CEMVR_Planning@usace.army.mil, or by writing to our address above.

 

PROJECT INFORMATION

The Des Moines River Basin has experienced significant land use changes. These changes influence runoff rates into tributaries of, and the main stem Des Moines River resulting in increased flood risk within the Des Moines River Basin. Following the 2008 Des Moines River flood, the District re-evaluated regulated flow frequencies on the Des Moines River. The Regulated Flow Frequency Study, completed in early 2010, concluded the frequency of flooding on the Des Moines River had increased and indicated major flood events, like 1993 and 2008, are more likely to occur than previously estimated.

The District is interested in your review and comments regarding the alternative analysis for this project. The District will finalize the EA after you have had a chance to comment. The District may also use the comments to determine the need for a public hearing and to determine the overall public interest of the proposed activity.

The following key issues inform the primary purpose and need of the Des Moines River Basin Master Reservoir Regulation Manual update:
1. The Des Moines River has experienced a significant increase in the magnitude and frequency of flooding.
2. Sedimentation within the reservoirs has negatively impacted available conservation (water supply) storage capacity.
3. Deviations from the approved water control plans, approved and conducted in recent years, demonstrate the need to permanently update the water control plans for each of these reservoirs. 

DECISION

The District proposes to update the water control manuals for Saylorville Lake and Lake Red Rock, and the Des Moines River Basin Master Reservoir Regulation Manual. The District identified alternative water control strategies that improve the projects’ ability to meet the congressionally authorized purposes, including reducing future flood risk and maintaining public safety. While it is impossible to eliminate all flood risk, the goal of this study is to modify the Des Moines River Basin Master Reservoir Regulation Manual to better manage the system resulting from changed hydrologic conditions. As discussed above, the project involves no new project design or construction.

 

PROPOSED AND ALTERATIVE ACTIONS

The final array of alternatives, 5A and 6, met all project goals and objectives with the exception of Goal 5 Objectives 5.a. Making improvements to the conditions for Red Rock and Ottumwa hydropower operations. Finally criteria used to select the recommended plan was based on which alternative reduced flood damages the most.

Based on the environmental assessment and the resulting damage summary, Alternative 6 is the preferred alternative and is recommended for replacing the current Des Moines River Basin Master Reservoir Regulation Manual. The recommended plan is not anticipated to be controversial in nature as local emergency managers, Iowa Department of Natural Resources, city and county governments, and NGO’s have been active project partners through the National Environmental Policy Act (NEPA) process. Additionally, the recommended plan requires no construction and no additional implementation or operational costs.