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|Title:||Ship effects before and after deepening of Sabine-Neches Waterway, Port Arthur, Texas|
|Authors:||Maynord, Stephen T.|
|Publisher:||Coastal and Hydraulics Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||ERDC/CHL TR ; 03-15.|
The Sabine-Neches Waterway is a confined navigation channel with a shallow berm adjacent to the navigation channel whose berm width varies from near zero to more than 800 ft in the Sabine-Neches Canal. Ship effects that attack the bank and possibly lead to bank erosion were compared in the before and after enlargement of the channel. Ship speed is the most critical and most difficult parameter to define in such a comparison. At ship speeds typically found in the SNWW, the shallow berm results in a large breaking wave forming adjacent to the shoreline. This wave, referred to herein as the transverse stern wave (TSW), moves at the ship speed and has a magnitude of up to 5.5 ft based on measurements reported herein and is calculated to be up to 8.4 ft for extremely fast ships in the proposed channel. The TSW is used herein to quantify and compare ship effects on the shoreline. HIVEL2D is a two-dimensional numerical model that was used herein to compare ship effects at SNWW. The model was validated using data from one of the ships measured during the field data collection portion of this study. Two scenarios were evaluated that have the potential for increased bank attack in the proposed channel. The first scenario is that ships currently using the SNWW will be able to travel faster in the larger proposed channel resulting in an increase in bank attack. The second scenario is that future ships will be larger than those using the existing SNWW and will cause larger bank attack. The two bank attack scenarios were evaluated using a range of speeds for ships in the existing and proposed channels. Results show that at the lower end of the range of speeds evaluated in the proposed channels, the TSW will increase in height less than 10 percent for both bank attack scenarios in both the Port Arthur and Sabine-Neches Canals. At the upper end of the range of speeds evaluated in the proposed channels, the TSW will increase an average of 35 percent in the Port Arthur Canal and an average of 17 percent in the Sabine-Neches Canal for both bank attack scenarios. The lesser change in the Sabine-Neches Canal is due to the smaller increase in cross section and the wider berm. Speed restriction tests were conducted with the proposed channel to determine speeds that will (a) result in equal TSW in the existing and proposed channels and (b) lessen TSW in the proposed channel compared to the existing channel.
|Appears in Collections:||Technical Report|