Hydrologic Engineering Branch

VARQ Flood Control Operation at Libby Dam and Hungry Horse Dam


In January 1999 the Corps of Engineers released a report documenting the work to date on the development of a flood control operation for Libby Dam and Hungry Horse Dam called VARQ. The report was written in response to the Supplemental Biological Opinion on the Operation of the Federal Columbia River Power System dated, May 14, 1998, requesting a status report on the progress of the VARQ studies.

VARQ was developed to improve the multi-purpose operation of Libby and Hungry Horse while maintaining the current level of system flood control protection in the Columbia River. VARQ reduces the contribution of reservoir space at Libby and Hungry Horse for system flood control of spring runoff in the Columbia River in years with low to moderate potential for flooding. The procedure was designed to provide higher outflows from the projects during the spring runoff than under the current flood control operation as outlined in the Columbia River Treaty Flood Control Operating Plan. These outflows are more consistent with releases made to meet flow objectives for the listed Endangered Species Act Kootenai River white sturgeon and Columbia and Snake River salmon and steelhead.

The report is comprised of an Executive Summary and four sections, which are listed below.

Section 1. The Effects of VARQ at Libby and Hungry Horse on Columbia River System Flood Control, with appendices, Appendix A. VARQ Operating Procedures

Section 2. Kootenai River Flood Control Study, Analysis of Local Impacts of the Proposed VARQ Flood Control Plan

Section 3. Local Effects of the Proposed VARQ Flood Control Plan at Hungry Horse Dam, Montana

Section 4. The Effects of VARQ at Libby and Hungry Horse on Columbia River System Hydropower


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U.S. Army Corps of Engineers, North Pacific Region Water Management Division
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Page Updated: Friday, 21-Nov-2003

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