CALIFORNIA GROUNDWATER QUALITY MONITORING: A UNITED VISION AMONG AGENCIES

The California Water Resources Control Board (SWRCB), in collaboration with the U.S. Geological Survey and Lawrence Livermore National Laboratory is implementing a statewide groundwater quality monitoring and assessment program (GAMA Program). In response to the many potential sources of groundwater contamination, Federal, State, and Local agencies each approach groundwater quality issues from the perspective of their own mandate. As a result, each agency collects different types of groundwater data and information. Despite the volume of groundwater-related monitoring data, data sharing and coordination between agencies has been limited.

Based on statewide public supply well water quality data monitored by the Department of Health Services, more than 8000 public water supply wells have been taken out of service in the last 20 years – many for water quality reasons. The MTBE scare of the late 1990s is being supplanted by concerns over perchlorate and other emergent chemicals. To adequately protect and manage California’s groundwater resources, it is imperative that California establish a baseline of groundwater quality and groundwater use for each groundwater basin in the state. Such a baseline can then be used as a reference for local management decisions, water quality trend monitoring, basin to basin comparisons, as well as establishing priorities for cleanup of surface contaminants that may affect groundwater.

In response to the Groundwater Quality Monitoring Act of 2001, the SWRCB convened an Interagency Task Force and a Public Advisory Committee, together representing more than 19 different Federal, State, local, and private entities. This interagency effort resulted in a publicly accepted plan to monitor and assess the quality of all priority groundwater basins that account for over 90% of all groundwater used in the state. The plan builds on the existing GAMA Program and prioritizes groundwater basins for assessment based on groundwater use. The primary objectives of the GAMA Program are to improve comprehensive statewide groundwater monitoring, create a centralized groundwater quality database, and increase the availability of groundwater quality information to the public. Key aspects of the program include interagency collaboration, data sharing, and communication with local water agencies.