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ARS Home » Southeast Area » Oxford, Mississippi » National Sedimentation Laboratory » Watershed Physical Processes Research » Research » Publications at this Location » Publication #154099
Title: PHYSICAL AND CHEMICAL CHARACTERISTICS OF SEDIMENT IMPOUNDED WITHIN GRENADA LAKE, MS

Author
item Bennett, Sean
item Rhoton, Fred

Submitted to: Laboratory Publication
Publication Type: Government Publication
Publication Acceptance Date: 9/17/2003
Publication Date: 9/17/2003
Citation: Bennett, S.J., Rhoton, F.E. 2003. Physical and chemical characteristics of sediment impounded within Grenada Lake, MS. USDA-ARS National Sedimentation Laboratory Research Report. No. 36. 161 pp.

Interpretive Summary: Grenada Lake flood control reservoir, built in 1954 by the U.S. Army Corps of Engineers, is located directly downstream of the Skuna and Yalobusha Rivers in north-central Mississippi. Along the Yalobusha River, severe channel erosion has caused the formation of a nearly 2-mi long woody debris plug. This plug has significantly increased the frequency and magnitude of flooding in nearby Calhoun City. Before the Corps of Engineers can initiate the removal of the plug and improve the conveyance of water, the amount of sediment already deposited within Grenada Lake must be determined to assess if impact of the upstream channel works on future patterns of lake sedimentation. Forty-seven continuous sediment cores were collected within Grenada Lake. Analysis of the cores allowed for the discrimination of sediment deposited since dam construction (post-impoundment) and parent material sediment (pre-impoundment). For the post-impoundment materials, sediments are primarily composed of clay, and the concentrations of environmentally important elements such as arsenic, cadmium, chromium, copper, manganese, mercury, lead, selenium, and zinc are about two times higher as compared to the pre-impoundment sediment. Select pesticides (aldrin, dieldrin, endosulfan I, BHC-alpha, BHC-beta, BHC-gamma, DDD, DDE, DDT, heptachlor, and heptachlor epoxide) are found in measurable concentrations. These data will serve as baseline information for the U.S. Corps of Engineers to determine if upstream channel works will impact future rates of sedimentation in Grenada Lake.

Technical Abstract: Grenada Lake flood control reservoir, built in 1954 by the U.S. Army Corps of Engineers, is located directly downstream of the Skuna and Yalobusha Rivers in north-central Mississippi. Along the Yalobusha River, severe channel erosion has caused the formation of a nearly 2-mi long woody debris plug. Before the Corps of Engineers can initiate the removal of the plug, the amount of sediment already deposited within Grenada Lake must be determined to assess if impact of the upstream channel works on future patterns of lake sedimentation. Forty-seven continuous sediment cores were collected within Grenada Lake. Analysis of the cores allowed for the discrimination of pre-impoundment sediments and post-impoundment sediments. For the post-impoundment materials, sediments are primarily composed of clay, and the concentrations of environmentally important elements (As, Cd, Cr, Cu, Mn, Hg, Pb, Se, and Zn) are about two times higher as compared to the pre-impoundment sediment. Select pesticides (aldrin, dieldrin, endosulfan I, BHC-alpha, BHC-beta, BHC-gamma, DDD, DDE, DDT, heptachlor, and heptachlor epoxide) are found in measurable concentrations. These data will serve as baseline information for the U.S. Corps of Engineers to determine if upstream channel works will impact future rates of sedimentation in Grenada Lake.