San Antonio Creek Spreading Grounds
The rehabilitated San Antonio Creek Spreading Grounds are designed to capture seasonal high-flows from San Antonio Creek to increase groundwater recharge in the Ojai Groundwater Basin.
In 1949, growers in the East End of Ojai formed a water reclamation district called the San Antonio Water Conservation District, which has since been renamed the Ojai Water Conservation District. The district was formed primarily to divert water into settling ponds along San Antonio Creek for groundwater recharge of the Ojai Valley Groundwater Basin, although the district is also authorized to monitor the use of groundwater, acquire water rights, and construct dams or other water facilities. The district established a series of stair-stepped settling basins on private property adjacent to upper San Antonio Creek, designed so that one would overspill into the next. It is estimated that there were dozens of these basins, each 20 to 30 feet long, 50 to 60 feet wide, and 6 to 10 feet deep.
“Between 1951 and 1963, groundwater recharge was conducted using an estimated 10,000 acre-feet of surface water imported from Matilija Lake via pipeline. The pipeline was eventually abandoned and groundwater recharge was conducted by diverting surface water from San Antonio Creek from 1963 to 1985. Surface flow was diverted through a 24-inch-diameter pipe equipped with an iron gate to control flow rates, and was reportedly available on a seasonal basis.”
— San Antonio Creek Spreading Grounds Rehabilitation Project: Project Description (Ventura County Watershed Protection District 2010)
Following the major “Wheeler Fire” of 1985, the Ventura County Flood Control District, now the Ventura County Watershed Protection District (VCWPD), was concerned that heavy rains could trigger a debris flow downstream and damage properties adjacent to San Antonio Creek. The VCWPD procured the 11.4-acre spreading grounds property and constructed a debris basin in the channel adjacent to the recharge basins. During basin construction, excavated material filled most of the spreading basins. In the early 1990’s, VCWPD and the Ojai Water Conservation District collaborated in an effort to reconstruct the basins, but the reconstruction was only partially successful, and the project was eventually abandoned.
In 2006, VCWPD secured funding to rehabilitate the San Antonio Creek Spreading Grounds, and construction was completed in the summer of 2014. The new facility is designed to divert surface water from upper San Antonio Creek into holding basins where the water then recharges groundwater through passive injection wells. Annual groundwater recharge is projected to average 126 AF per year with a maximum of 914 AF per year. The project was a collaboration between the OBGMA and the VCWPD. Casitas Municipal Water District is also a project partner that will help with facility maintenance.
Source: Ventura River Watershed Management Plan (Walter 2015)