Design of Sediment Trap at Rollover Pass, Texas
Abstract
Rollover Pass is a narrow manmade channel, which connects the Gulf of Mexico and Rollover Bay. The Gulf Intracoastal Water Way (GIWW) crosses the Rollover Bay on the north side of Rollover Pass. The U.S. Army Engineer District, Galveston, maintains a navigation channel, 38 m (125 feet) wide and 3.6 m (12 feet) deep within the GIWW for commercial barge traffic. Over the past several years considerable siltation has been taking place within the GIWW in the vicinity of the Rollover Pass area and periodic dredging is required for maintaining navigable depths. The objective of the study was to construct a working numerical model of the Rollover Pass area, and to use the model for design of a sediment trap, which will be feasible and effective in reducing the frequency of dredging in the GIWW. The hydrodynamic model code RMA2, available at ERDC-CHL, was used to calculate the hydrodynamics of the system with a two-dimensional numerical model. The model was verified using field data. Velocity patterns under selected tidal conditions were generated. Computation and analysis of bed shear stress patterns were used along with the velocity data to estimate where and by how much sediment deposition is expected to occur. Several alternatives of sediment trap in terms of location, shape, size and depth were considered for evaluation. The factors taken into account in the design of the trap are described in the report. Three configurations out of these were examined with the model: (1) a sand trap proposed by the Galveston District, (2) a tentative layout of sand trap based on field data, and (3) modified final layout based on the results of the tentative layout. The final layout has a length of 915 m (3,000 feet) and a width of 122 m (400 feet). The trap is separate a from the GIWW by at least 61 m (200 feet). Recommended design depth in the trap is 2.75 m (9 feet). The merits of this layout are described in the report.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2000
- Accession Number
- ADA384299
Entities
People
- Ben Brown
- Robert T. Mcadory
- Trimbak M. Parchure
Organizations
- Engineer Research and Development Center