Movement of Tagged Dredged Sand at Thalweg Disposal Sites in the Upper Mississippi River. Volume 3. Additional Results at Gordon's Ferry and Whitney Island Sites.
ARGONNE NATIONAL LAB IL ENERGY AND ENVIRONMENTAL SYSTEMS DIV
Pagination or Media Count:
During routine channel maintenance, hydraulically dredged sand was tagged with sand coated with fluorescent dye before being deposited as a pile in the thalweg at three sites on the Upper Mississippi River. As discussed in the first two volumes of this report, bathymetry was measured and surface sediments were sampled to study changes in the topography of the disposal pile and the downstream movement of the tagged sand. At all three sites, topographic evidence of the pile disappeared after the first period of high river flow, which was followed by redevelopment of dunes in the disposal area. The tagged sand did not migrate into nearby border areas, backwaters, or sloughs, remaining in the main channel as it moved downstream. This volume presents the results of additional surveys at the Gordons Ferry and Whitney Island sites. At Gordons Ferry, 25 bottom cores were taken to examine the three-dimensional distribution of tagged sand in the bottom sediments. The core analyses indicated that much of the tagged sand had been incorporated into the dune structure and that it resided primarily in the crests of the dunes. Keywords Illinois, Missouri.
- Hydrology, Limnology and Potamology