Scaphirhynchus Conference: Alabama, Pallid, and Shovelnose Sturgeon

St. Louis, Missouri, 11-13 January 2005

52.  SHALLOW WATER STURGEON HABITAT FOR THE LOWER MISSOURI RIVER.

Donald G. Jorgensen, Missouri River Technical Committee of the Siouxland Chamber of Commerce, 101 Pierce Street, Sioux City, IA 51103, Phone 605-966-5645; donjorg@longlines.com

William M. Beacom, Missouri River Technical  Committee of the Siouxland Chamber of Commerce, 101 Pierce Street, Sioux City, IA 51103; Phone 712-255-3412, bbeacom@pionet.net

Donald M. Meisner, Missouri River Technical Committee of the Siouxland Chamber of Commerce, 101 Pierce Street, Sioux City, IA 51103; Phone 712-223-0408, skip@simpco.org

The U.S. Fish and Wildlife Service in the Amendment to the Biological Opinion for the Missouri River (2003) has asked for a summer low-flow release of 25,000 cfs from Gavins Point Dam, South Dakota and Nebraska for the purpose of increasing shallow-water habitat for the pallid sturgeon. An investigation of such a release was made to evaluate the effect of that release on the amount of shallow-water habitat (areas of water depth less than 5 feet and velocity less than 2.5 feet per second).

Analysis of existing information indicates the surprising result that flows of 40,000 cfs at Boonville, Missouri, during the summer would be beneficial in maximizing shallow-water acres of habitat for fishes including the pallid sturgeon, especially, in the Boonville to St. Louis reach, which is recognized as having a pallid sturgeon population.  During dry years, it is likely that releases from Gavins Point Dam would have to significantly exceed 25,000 cfs to maintain a flow of 40,000 cfs at Boonville. Available data indicates that a reduction of flow from 40,000 to 35,000 cfs at Boonville can be expected to reduce shallow-water habitat of the Lower Missouri River about 1,100 acres or 13 percent during dry years.   The years of 2002 and 2003 provide actual examples of the effects of low releases from Gavins Point Dam on the discharges at Boonville. In 2002, the release of 25,500 cfs from Gavins Point Dam during July and August resulted in flows of only 32,000 cfs at Boonville, or 8,000 cfs short of the 40,000 cfs required to maximize shallow-water acres. Similarly in 2003, a release of 26,000 cfs from Gavins Point Dam resulted in flows of only 30,000 cfs in late August at Boonville, or about 10,000 cfs less than flow required to maximize shallow-water acres.