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|Title:||Evaluation of disposal areas in James River : hydraulic model investigation|
|Authors:||United States. Army. Corps of Engineers. Norfolk District.|
Boland, Robert A.
Bobb, William H.
Waste disposal area
|Publisher:||Hydraulics Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||Miscellaneous paper (U.S. Army Engineer Waterways Experiment Station) ; H-75-1.|
Abstract: The existing comprehensive fixed-bed model of James River was used to study the major disposal areas used during maintenance dredging operations for the existing 25-ft-deep navigation channel to determine if the disposal areas are performing satisfactorily in terms of retaining dredged material placed therein. If the test results indicated a probable excessive rate of return of dredged material to the channel, the tests were expanded to include studies of an alternate area or areas in the same general vicinity to determine if a more suitable disposal area could be defined. The tests consisted of the release of lightweight sediments at surface depth in the disposal areas, tracing patterns of movement of material from the areas, and defining areas where these sediments would probably deposit. The results indicated that, in general, the disposal areas and operating procedures presently employed are satisfactory with respect to areas of material deposition and material retention characteristics. Maintenance requirements for the Skiffes Creek channel would probably be reduced if use of the downstream 4000 ft of the Tribell shoal disposal area is shifted to the opposite side of the channel. A significant portion of the material discharged in the downstream 8450 ft of the Goose Hill shoal disposal area returns to the navigation channel, and shifting that portion of the disposal area to the north side of the channel should improve this condition. Releasing material in the Jordan Point-Windmill Point disposal area 2 results in rapid filling in Herring Creek which is probably objectionable. The sediment trap suggested for the Jordan Point-Windmill Point shoal reach would not function to the extent required and is not recommended. The estimated annual loss of depth in all disposal areas tested, except at the downstream half of Jordan Point-Windmill Point shoal reach, was 0.10 ft or less for the present shoaling rates, indicating an extended period of future use without adverse effects. The estimated annual loss of depth in the downstream Jordan Point-Windmill Point disposal areas 1 to 5 varied between about 0.10 and 0.40 ft, indicating this reach to be the most critical with respect to continuing present channel maintenance practices. Alternate disposal schemes for this reach should be developed. Further tests should be conducted in the model to determine the effects of filling the disposal areas to minimum allowable depths. For example, the disposal areas could be completely filled to some assumed condition that would exist in the future because of continued use. The disposal tests could be repeated for the future filled condition to determine associated changes in hydraulic, salinity, shoaling, and dispersion conditions. Estimates of the environmental impact of all disposal areas could then be made.
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||Miscellaneous Paper|
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