To address applicable total maximum daily loads (TMDLs) and water quality priorities, the Upper Los AngelesRiver (ULAR) Enhanced Watershed Management Program (EWMP) Plan identified the need for this project. Implemented by the City of San Fernando, this project aims to not only improve water quality but divert and capture wet and dry weather runoff from more than 940 acres, which will reduce pollutant loads that would otherwise enter Pacoima Wash and the Los Angeles River.
The goal is for captured runoff to be pretreated and discharged into a subsurface storage system that will operate infiltration at the San Fernando Regional Park and aid in groundwater recharge. The project team said the project has a single storm capture volume of more than 24 acre-feet and recharges more than 320 acre-feet annually.
Before the project could be imple- mented, the team had to overcome several challenges. Funding was eased through grants and other programs, but during the design phase, the team had to work around a limited footprint for the subsurface system.
The system needs significant excavation and stockpiling because the invert of the infiltration system is nearly 30 feet deep. To combat this, the contractors installed it in three phases and braced the system, which was able to stockpile on top of installed sections. Upon completion, the project has prompted the team to pursue similar opportunities.
“The project success has encouraged the city of San Fernando to pursue additional funding opportunities to implement other projects like it within their community,” Katie Harrel, special projects manager for CWE, said.