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Source: https://erdc-library.erdc.dren.mil/jspui/ This report presents the sedimentation findings from combined physical and numerical model tests (hybrid modeling) of deepening the approach channels to Norfolk and Newport News, Virginia. Because of the varying nature of shoaled material along the project navigation channel, the tests included two separate numerical sediment transport models, which were referred to as the Thimble Shoal model and the Elizabeth River model. The sediment along the Thimble Shoal portion of the navigation channel consists predominantly of noncohesive material while the sediment along the Elizabeth River portion of the navigation project consists primarily of clays and silts. Sedimentation in a third portion of the overall project, referred to as the Atlantic Ocean Channel, was evaluated analytically without using a numerical sediment transport model. Based on sedimentation results from the Elizabeth River numerical model, the increase in shoaling caused by channel deepening as proposed will be 23 percent. The distribution of shoaled material will not be significantly altered, other than a slight increase in skewness toward the downstream end. Based on sedimentation results from the Thimble Shoal numerical model, the increase in shoaling caused by channel deepening as proposed will be about 20 percent. The distribution of shoaled material will be slightly altered in that both the upper and lower channel shoaling peaks which presently exist will tend to migrate even more toward the ends of the dredged channel. Based on the analytic analysis, the estimate of shoaling for the new Atlantic Ocean Channel is about 200,000 cu yd annually. |
