Desalination/Aquifer Storage Recovery (DASR): a cost-effective combination for Corpus Christi, Texas

A project is under development at Padre Island and Mustang Island, Corpus Christi, Texas, combining desalination of brackish groundwater with ASR storage of treated drinking water, both utilizing brackish, confined sand aquifers and clay confining layers at depths of less than 250 m. The combination of these two technologies, referred to as “DASR,” is a cost-effective water management approach that enables efficient, base load operation of desalting facilities at steady rates while meeting peak demands with water stored in ASR wells. The initial target yield of demonstration DASR facilities is 20 Ml/D peaking capacity, to be met with 4 Ml/D of desalination, 8 Ml/D of ASR capacity, and about 8 Ml/D of imported water supply from a pipeline to the mainland. In subsequent phases, capacity would be expanded to meet increasing demands. The project involves providing both brackish water supply and ASR well capacity using horizontal directional drilling (HDD) technology, in addition to vertical wells, since available site location opportunities are quite limited. Several wells would be located at each site, effectively developing high well yields from relatively shallow, thin, sand aquifers without risking subsidence due to excessive drawdowns beneath this low coastal barrier island. This will be the first use of HDD technology for construction of ASR wells, and one of the first applications of this technology for any water supply wells. Initial test well construction is under way, to be followed by construction and testing of full scale demonstration facilities. Completion of initial facilities is planned by about the end of 2005. ASR Systems LLC has been selected to provide consulting engineering and hydrogeological services as part of a team of companies led by Carollo Engineers PC.