Arroyo Seco Urban Water Quality Improvement Projects


Arroyo Seco Urban Water Quality Improvement Projects: #1 – Sycamore Grove Park (AS-15) and #2 – Hermon Dog Park (AS-21)

The AS-15 Dry Weather Diversion (DWD) system is located adjacent to Sycamore Grove Park at the southeast corner of N Figueroa St and S Avenue 49. The DWD will divert maximum dry weather flow of 0.32 cfs from a City-owned 9 ft x 9 ft box culvert storm drain which runs perpendicular to the Arroyo Seco Parkway. Flow will enter the 42-inch sanitary sewer located at the Sycamore Grove Park access road.

The AS-21 DWD system is located at Hermon Dog Park north of Via Marisol Street and south of Monterey Road. This DWD will divert a maximum dry-weather flow of 0.03 cfs from a City-owned 24-inch diameter storm drain and a 30-inch diameter storm drain which run through Hermon Dog Park to an 18-inch sewer line in Via Marisol.

Status: Design Completed, Construction anticipated early 2021 and Completed March 2022
Cost: $4,966,060
Funding: Safe Clean Water – Measure W (Municipal)
Agency Lead: City of Los Angeles
Footprint: N/A – diversion structures
Drainage Area: 1,135 acres (#1); 267 acres (#2)
Volume Capture: N/A – diverting 0.32cfs (#1) and 0.03 cfs (#2) to sanitary sewer
Implemented Control Measures: Diversion structure
Key Benefits: Water quality