Regional Sediment Management Studies of Matagorda Ship Channel and Matagorda Bay System, Texas
ENGINEER RESEARCH AND DEVELOPMENT CENTER VICKSBURG MS COASTAL AND HYDRAULICS LAB
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Three research and development programs within the US Army Engineer Research and Development Center ERDC have collaborated to investigate regional sediment management strategies within the Matagorda Bay system, emphasizing the excessive shoaling in the upper reach of the Matagorda Ship Channel MSC. These three RD programs were the Regional Sediment Management RSM Program, Coastal Inlets Research Program CIRP, and Dredging Operations and Environmental Research DOER Program. Extensive shoaling in the upper reach of the MSC in recent years has resulted in the need for annual maintenance dredging. The increasing channel shoaling rate is likely due to the placement of dredged material into adjacent open water sites west of the channel and the migration of these fluidized sediments back into the channel. It is suspected that active sedimentation in upper Lavaca Bay also contributes to the high shoaling rate in the MSC. Stronger wave action in Lavaca Bay and Matagorda Bay during fall and winter months evidently increases the amount of suspended sediment, especially cohesive sediment, and promotes more sediment deposition in the MSC. Numerical simulations were conducted to investigate the existing Matagorda Bay conditions and three alternatives as proof-of-concept to reduce sediment deposition in the upper MSC 1 a confined artificial island south of Port Comfort, located in the northeast portion of the bay to contain the dredged material from the upper channel, 2 extension of an existing geotube east of the upper channel to close the gaps between dredged material placement areas, and 3 three new placement areas west of the navigation channel. The present study showed these alternatives could effectively reduce the channel shoaling rate. Options to reduce maintenance dredging by surveying the channel such that the fluid mud interface could be defined are also discussed.
- Hydrology, Limnology and Potamology