Happy Valley Bioswale

Description of the Project:

The project is located in the County of Ventura unincorporated community of Meiners Oaks in the upper Ventura River Watershed (VRW). This watershed is subject to Total Maximum Daily Loads (TMDL) for Algae, Eutrophic Conditions, and Nutrients in Ventura River and its tributaries. The County of Ventura in cooperation with the Ojai Valley Land Conservancy (OVLC) constructed Happy Valley Bioswale, an enhanced vegetated swale, to reduce urban runoff pollutant loading to the Happy Valley Drain, a tributary of the impaired Ventura River. Typical swales range from 2-3 feet wide, about 100 feet long, and are 6 – 12 inches deep. Happy Valley Bioswale has a 10-foot wide flowline, is 45 feet wide at ground surface, has a maximum depth of 3.5 feet, and is 300 feet long in a horseshoe pattern. This massive vegetated swale treats runoff from 37 acres of urban area (40% of the Meiners Oaks community area) for treatment of an estimated 1.6 million cubic feet of annual runoff. The $400,000 construction was primarily funded by the Proposition 84 Stormwater Grant Program.


A diversion structure was constructed to intercept flows from an existing 24-inch diameter County storm drain pipe that parallels the project site. The swale was enhanced with incorporation of a high-flow nutrient removal baffle-box to pre-treat the water allowing settlement of sediment and capture of trash and vegetative debris prior to entering the swale. The water then flows through the vegetated swale removing additional pollutants by natural filtration, minor infiltration and evapotranspiration. An inline check valve has been installed at the end of the swale where it discharges back into the existing storm drain to prevent backflow into the swale during large rain events.

For more information, refer design and landscape plans, and project Power Point presentation or call Ewelina Mutkowska at (805) 645-1382 or send an email to ewelina.mutkowska@ventura.org