San Diego Hydrogeology

Welcome to the U.S. Geological Survey (USGS) San Bernardino Optimal Basin Management website. This site provides hydrologic data collected or compiled by the USGS for the San Bernardino area. Also provided is a comprehensive listing of reports, including links to online reports. Please use the San Diego Hydrology navigation links located above to access project overview, maps, figures, data, references, and contacts.

Real-Time Streamflow Sites

Real-time sites - Data from automated equipment and represent the most current hydrologic conditions. Measurements are commonly recorded at 5-60 minute intervals and transmitted to the NWIS database every 1-4 hours. Values in pop-up bubbles are updated hourly from NWIS. Additional data for real-time sites.

Daily-value sites - Data are summarized from time-series data for each day for the period of record and may represent the daily mean, median, maximum, minimum, and/or other derived value. Daily values include approved, quality-assured data that may be published, and more recent provisional data, whose accuracy has not been verified. Example.

Field measured streamflow and lake sites - Periodic manual measurements of streamflow and gage height at streamflow and lake sites. These measurements are often used to supplement and (or) verify the accuracy of the time-series measurements. The last value available is shown in the pop-up bubble for each site. Additional data for surface-water sites.

Data are provisional and subject to revision.