Slant Well Technology: A Desalination Intake Alternative

To allieviate environmental stresses on the Carmel River, the State Water Resources Control Board required California American Water Company (Cal Am), the utility responsible for providing water to a substantial portion of the Monterey Pennisula, to reduce its reliance on diversions from the Carmel River to serve as its local water supply. To meet this state mandate, Cal Am instituted the process of planning and permitting a seawater desalination project.

The purpose of the Monterey Peninsula Water Supply Project (MWSP) is twofold: to remediate pressure on the local municipal water supply aquifer, and to contribute to much needed local water supplies. The project will provide up to 10 mgd of desalinated water supply to northern Monterey County. In addition, the MPWSP will help reduce and remediate seawater intrusion from overdraft conditions, which is an ongoing water quality issue identified as early as the 1930s.

GEOSCIENCE has been responsible for providing the hydrogeologic characterization of the area, groundwater modeling to develop the aquifer testing program which included exploratory drilling and testing program to assess baseline conditions and refine the test slant well design. The 1,000 ft test slant well has been constructed and is in a long term (18-24 months) pumping test phase to develop feedwater parameters and evaluate potential impacts to sensitive habitat and inland water resources. An extensive monitoring program has also been designed by GEOSCIENCE that will accompany the long-term pilot testing and develop the baseline to compare potential impacts.

GEOSCIENCE’s approach and solutions included:

  • Slant Well Rehabilitation Study
  • Well casing studies
  • Geotechnical Input Regarding Slant Well Location and Protection
  • Water Modeling & Geochemical Characterization
  • Coastal Groundwater Model Development
  • Impacts of Slant Well Extraction Scenarios
  • Identification & Analysis of Energy Strategies