Numerical Modeling of Hydrodynamics Brazos Island Harbor Project, Texas (Brownsville Ship Channel)

Abstract : This project was authorized for navigation channel improvements, which include deepening of the Brownsville Ship Channel from 38 ft below mean low water (mlw) to 42 ft below mlw and channel widening. The 19-mile-long Brownsville Ship Channel begins in the Gulf of Mexico, transects the Laguna Madre, and continues landlocked to Brownsville. This study involved the use of the vertically integrated two-dimensional numerical model RMA-2V to simulate the ship channel and the lower Laguna Madre. RMA-2V was used to produce the hydrodynamics (water levels and velocities) for existing and three alternative channel designs. These hydrodynamic conditions were used in a ship simulator study. Historical velocity (direction and speed) measurements taken at approximately hourly intervals during 15-18 July 1980 at several stations were used to verify RMA-2V. Water level measurements from four tide gages were also available for the same period to facilitate model verification. While some difficulties occurred in reproducing measured water level responses in the interior of the Laguna Madre, good numerical model simulation of velocity directions and magnitudes was obtained in the Brazos Island Harbor Projects area. Keywords: Mathematical/hydraulic models; Tidal currents; Channels waterways; Computerized simulation.