TxDOT FM 3005, San Luis Pass to Galveston Seawall

Improving Drainage for a Raised Coastal Highway on Galveston Island

Project Purpose

In response to heavy flooding along the Gulf Coast caused by major storms in recent years, TxDOT has been completing projects to elevate coastal roadways for flood risk mitigation. This project on Galveston Island will raise an 18.7-mile portion of FM 3005 (also known as Termini San Luis Pass Road) by 18 inches to a minimum elevation of 7.5 feet above sea level. Since this stretch of the roadway is not protected by the seawall, the elevation increase and improved drainage will help protect against heavy rainfall and tidal surges.

Project Approach

As a subconsultant, our role was to design the roadside ditches, driveway culverts, and storm sewer systems to tie to proposed cross culverts designed by the prime firm. Improvements to parallel drainage will:

  1. provide positive drainage to direct stormwater to outfalls, and
  2. correct movement that has occurred over time due to the settling of sandy soils. Parallel drainage was designed to convey the 10-year storm event. Due to the extremely flat topography of Galveston Island, KFA redesigned flat ditches to provide positive conveyance and to minimize construction disturbance at driveways.

Project Results

This project is currently under construction and is scheduled to be completed in 2022.  The project will improve the serviceability and safety of the primary access roadway along the western portion of Galveston Island.