Groundwater Assessment Program

Marlon Cook, Director

Assessments
- • Local projects
- • Regional & statewide projects

Information Distribution
- • Continuous monitoring wells
- • Periodic monitoring wells
- • Scanned well records

Geochemical Analyses

Reports
- • Selected water-related publications by county
- • GSA on-line reports
- • Open-file Reports

Groundwater level records

Continuous Monitored Wells

Long-term hydrographs from monitoring wells provide an indicator of water level fluctuation affected by groundwater withdrawals, land use, and climatic changes. The period of record for some of the wells continuously monitored by the GSA is longer than 60 years, providing excellent data for trend analysis. The response of groundwater levels to meteorological drought is generally slower than other drought indicators such as soil moisture and streamflow and can provide information related to drought intensity and duration.

The GAP currently operates 19 continuous groundwater-level monitoring wells equipped with digital recorders that record water levels every 2 hours and store the data in a data logger. The data are retrieved on a routine basis. These continuous records provide insight into how groundwater levels fluctuate in response to climate variability and groundwater withdrawals.

In early 2010, the GAP will initiate a real-time groundwater-level monitoring program. Thirty wells in strategic locations and aquifers will be equipped with automatic digital recording equipment and a telemetry interface system, which will transmit data by satellite or cellular signal directly to the GAP offices. The data will be uploaded to the GAP web site on a regular basis.