Map of the Northern Cities region
Northern Cities of San Luis Obispo County

Key Issues

  • Existence of overdraft and rights to pump groundwater
  • Degree of connection to the adjacent Nipomo area and status of Northern Cities as a distinct management area
  • Need to monitor and manage for sustainable supply


  • Provision of expert testimony on the hydrogeologic setting and water balance
  • Systematic water balance study that revealed significance of potential seawater intrusion
  • Development of monitoring and reporting program to comply with the adjudication and support local groundwater management
  • Restoration of coastal sentry well monitoring to provide early warning of seawater intrusion

Expert Witness Services, Santa Maria Groundwater Basin Adjudication

San Luis Obispo County, California

San Luis Obispo County and the Northern Cities — Arroyo Grande, Pismo Beach, and Grover Beach — and Oceano retained Todd to provide groundwater expertise in the adjudication that questioned their rights to pump groundwater for municipal purposes and to conduct local groundwater management.

Todd Groundwater (then operating as Todd Engineers) was retained jointly by legal counsel for San Luis Obispo County (Kronick, Moskovitz, Tiedemann & Girard) and the Northern Cities of Arroyo Grande, Pismo Beach, and Grover Beach, and Oceano Community Services District (represented by Nossaman) to provide technical support in the Santa Maria Groundwater Basin adjudication. The Santa Maria adjudication involved water rights litigation among numerous public agencies and private well owners in northern Santa Barbara County and southern San Luis Obispo County.

Specific issues included whether or not an overdraft condition exists, the status of the Northern Cities Area as a distinct subarea, and the degree of connection of the Northern Cities Area to the adjacent Nipomo Basin and the rest of the groundwater basin. In addition, the role of Lopez Reservoir was examined. Dr. David Keith Todd testified on Northern Cities Area issues including the hydrogeologic setting and groundwater levels and flow. Dr. Iris Priestaf testified on Lopez Reservoir issues and the water balance of the Northern Cities area. In early 2008, after more than 10 years of litigation,the Judgment of the Superior Court was posted and the County and Northern Cities emerged victorious.

With regard to the Northern Cities, the judgment affirmed their prior and paramount right to produce 7,300 acre-feet of water per year from the Northern Cities Area of the Basin. The Superior Court retained continuing jurisdiction to protect the basin from future harm, to resolve future disputes, and to enforce the previous 2005 settlement stipulation that requires annual groundwater monitoring and reporting. Todd subsequently assisted the Northern Cities with its groundwater management. This included systematic documentation of the local water balance, which revealed the importance of subsurface outflow that prevents salt water intrusion into the basin.

Todd subsequently prepared a monitoring and reporting program as the basis for improved management. This program involves data collection (climate, groundwater levels and quality, water supply and demand), update of electronic databases (GIS, spreadsheets, and databases), review of available data in light of monitoring objectives, design and implementation of the program, and preparation and presentation of an annual report. Todd also assisted with the restoration of several coastal sentry wells and initiation of groundwater level and quality monitoring to provide an early warning system against seawater intrusion.