A completed study examines major regions of Galveston Bay where submerged halophytes have declined since the 1950's and compares them with nearby remaining sites where plants still persist. The approach involved compilation and analysis of active processes and hydrologic data, which could affect distribution and abundance of rooted estuarine plants. After the SV distribution at different time periods was mapped, physical and hydrologic factors were analyzed in an attempt to establish the processes contributing to impacts on SV habitats.