California Water Science Center (CAWSC) - Yucaipa Valley Optimal Basin Management (OBM)

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Yucaipa Valley Hydrogeology

Welcome to the U.S. Geological Survey (USGS) Yucaipa Valley Hydrogeology website. This site provides hydrologic data collected or compiled by the USGS in the Yucaipa area; some additional data may be available from the USGS database National Water Information System (NWIS).

Project Chief: Greg Mendez
Phone: 619-225-6176




The Yucaipa area is about 12 mi southeast of the city of San Bernardino and about 75 mi east of the city of Los Angeles in the upper part of the Santa Ana River drainage basin. Since about 1970 and especially during the 1990's, the widespread urbanization of southern California has extended inland from the coast into the Yucaipa area. Undeveloped land, agricultural land, and sparsely populated residential land have been converted into housing tracts. The net effect of this change in land use has been an increase in the demand for water, especially potable water for domestic use. Because the local supply of both surface water and ground water is limited in this semiarid region, water purveyors need an accurate assessment of water resources.



This study assesses the quality of water in the Yucaipa area, primarily in the Yucaipa plain. This hydrogeology study will aid local water purveyors in understanding and evaluating local resources and using those resources effectively in combination with water imported from northern California and from the adjacent San Bernardino area.

As part of a comprehensive hydrologic investigation in the Yucaipa Basin, efforts are focused on continuing to track the movement of imported water released into the Wilson Creek spreading ponds. To do this, water-quality data were collected and analyzed from 13 wells to monitor the absence or presence of imported water. Depth-dependent water-quality sampling was collected to determine recharge in selected areas. Water-quality data were collected and analyzed from 8 wells in the Crafton and Western Heights subbasins to access background levels of several constituents potentially influenced by recharge of water in spreading ponds expected in the near future.
USGS works together with several water agencies and general public in the Yucaipa area to develop hydrogeologic understanding and water management plans for groundwater in the area.

The USGS will be providing the necessary technical guidance and support for SBVMWD to ensure success of the management plans.



Tracking the signal of imported water through the subsurface will be used to determine the direction of groundwater flow from recharge processes. Water-level monitoring will be used to measure pressure response from the decline of recharge activities. Continued collection of field measurements provide independent estimates of the magnitude and/or location of groundwater recharge that can be compared with and used to constrain estimates from future hydrologic models. Surface resistivity and duration of flow data will be used to help identify areas where recharge from streamflow may be occurring.