BRAZOS RIVER FLOOD GATE PROJECT: UNDERSTANDING HYDRODYNAMICS AND SEDIMENTATION USING NUMERICAL AND PHYSICAL MODELS

Brazos River Floodgates (BRFG) are located where the Gulf Intracoastal Waterway (GIWW) intersects with the Brazos River southwest of the city of Freeport in Brazoria County, Texas. The gates were initially installed in the early 1940s to prevent heavy sediment loads in the Brazos River from entering the GIWW. The structures were installed at a time when most tugboats pulled barges behind them, rather than using the modern pushing method. The gate openings are 75 feet wide, which is narrower than the 125 feet wide and 12 feet deep GIWW navigation channel. Although regulations restrict the width of tows to 55 feet, oversize tow permits are routinely granted for tows as wide as 108 feet, particularly along the upper Texas coast. To move these wider tows through the BRFG, vessel operators must park the tows, break the barges apart, move them through the gates in smaller sets or individually, and reconnect the tows on the other side. This process, known as “tripping,” is inefficient and causes delays that result in substantial costs to the towing industry each year. Difficulty in navigation through the BRFG results in temporary navigation restrictions and/or closures imposed by the USACE and U.S. Coast Guard. These restrictions and closures result in additional delays and economic impact to the towing industry.