Coastal evaluation and planning for development of subsurface intake systems

The feasibility of using a subsurface intake system for a seawater reverse osmosis (SWRO) water treatment plant is based on the site-specific hydrogeologic conditions which control the type of intake design that can be used and the capacity of the intake. Planning for future development of subsurface intake systems requires a careful analysis of the shoreline and shallow offshore area. Example regions, the Red Sea coast of Saudi Arabia and the shoreline of Florida (USA), were investigated to develop general feasibility criteria for possible development of SWRO intake systems. Within the Red Sea, it was found that various well intake systems could be feasible for low-capacity SWRO facilities and high capacity intake systems would be limited to seabed gallery intakes. Coastal Florida had more subsurface intake options available, including wells, beach galleries, and seabed galleries which could be used based on the required capacity and the specific site conditions. The presence of high transmissivity carbonate aquifers containing seawater in Florida would allow medium capacity SWRO systems to use conventional vertical wells. High capacity systems could be developed using beach gallery systems in many locations. The methods developed for shoreline and nearshore evaluation contained herein could be applied to any coastal region of the world for subsurface intake evaluation.