Accession Number : ADA190426

Title :   Management of Environmental Resources of Cutoff Bends Along the Tennessee-Tombigbee Waterway.

Descriptive Note : Final rept.,

Corporate Author : ARMY ENGINEER WATERWAYS EXPERIMENT STATION VICKSBURG MS ENVIRONMENTAL LAB

Personal Author(s) : Shields, F D , Jr

PDF Url : ADA190426

Report Date : Nov 1987

Pagination or Media Count : 206

Abstract : Construction of the Tennessee-Tombigbee Waterway (TTW) involved construction of a navigation channel across the necks of 35 meander bends of the Tombigbee River. The cutoff bends, or bendways, constitute a valuable resource that the Corps of Engineers is committed to maintain. This study was conducted to provide a rational basis for refinement of the management strategy for the 30 TTw bendways located downstream of Aberdeen Lock and Dam. The five bendways in Aberdeen Pool were not considered in this study. Bendway sedimentation may be conceptually divided into two phases: blockage and infilling. Discharge, suspended sediment concentration, and repetitive hydrographic survey records for 20 man-made cutoff bends and associated cut channels and for one natural chute cutoff were used to study the rate of sedimentation during the blockage phase. The variation of bendway channel cross-sectional area with both time and distance along the bend showed that for most bends, deposition patterns tend to be bimodal, with a primary location for deposition just below the upstream entrance and a secondary location just above the downstream entrance. Sequential aerial photographs of seven cutoffs bends were used to study infilling rates. The perimeter of the treeline and the area enclosed by the treeline around each were measured for each photography coverage date. Specific recommendations are provided for management of each of the 20 TTW bendways downstream of Aberdeen Lock and Dam. Construction of blockage embankments of the upstream end is recommended for 27 of the bendways. Three of these 27 blocks were constructed in 1985.

Descriptors :   *TOMBIGBEE RIVER, CHANNELS, NATURAL RESOURCES, CHANNELS(WATERWAYS), CONCENTRATION(COMPOSITION), CROSS SECTIONS, CUTTING, DEPOSITION, ENVIRONMENTS, HYDROGRAPHIC SURVEYING, MANAGEMENT, NAVIGATION, PATTERNS, PHOTOGRAPHY, RATES, RECORDS, RESOURCES, SECONDARY, SEDIMENTATION, SUSPENDED SEDIMENTS, TENNESSEE, VALUE, AERIAL PHOTOGRAPHY, CURVES(GEOMETRY)

Subject Categories : Civil Engineering

Distribution Statement : APPROVED FOR PUBLIC RELEASE