Talbert Lake Stormwater Diversion and Wetland Treatment System
Huntington Beach, CA
PACE provided planning and design for a flood control channel diversion system and wetland stormwater treatment system to treat at least 3 MGD of stormwater that would otherwise flow directly into the Bolsa Chica Wetlands and Huntington Harbor and further impair the water bodies. An innovative treatment system was developed specifically for a 22 square mile Orange County watershed tributary to the East Garden Grove-Wintersburg Channel in Huntington Beach, CA. The project diverts the flows from the channel to the existing City Central Park. The system relies on interconnected key components which include: (1) a flexible in-channel collection system, (2) conveyance system to the treatment train, (3) primary wetland treatment train system, (4) manmade lake polishing treatment system, and (5) groundwater recharge and reuse. An inflatable rubber dam in the existing concrete channel captures and temporarily stores the dry-weather flows while avoiding impacts to the flood control capacity. A forebay and pump station underneath the channel access road which pumps the flows to Central Park located approximately one mile away. The dry-weather flow delivered to Central Park is distributed to three independent wetland treatment cells which are composed of several interconnected shallow wetlands and wetland ponds. The wetland cells include surface and specialized subsurface wetland treatment elements that utilize surface area for the growth of bacterial biofilters. The outflow from the wetland treatment system discharges for final polishing into the existing manmade Talbert Lake which provides stormwater treatment, groundwater recharge, park irrigation and ensures a year-round permanent water body since the lake was previously subject to drying up in low rain event years. The restored manmade lake system is specifically designed for stormwater treatment utilizing (1) submerged media biofilters, (2) lake aeration, (3) in-lake pumped circulation, and (4) water quality filters and wetland planters. The water quality of the restored engineered lake is designed to recreate the natural biological processes and develop a managed ecosystem that provides water quality treatment.
Using a combination of engineered wetlands and the restored Talbert Lake, this project provides urban dry-weather runoff treatment for a 22 square mile municipal watershed. This system involves the diversion of nuisance flows from a regional flood control channel to the wetlands area, a series of interconnected wetland treatment cells and manmade lake polishing systems. By recreating a natural biological process, this project develops a managed ecosystem that provides water quality treatment.
- In-channel flow interception facility capable of capturing dry-weather flows but not interfering with the flood control channel hydraulic capacity.
- Underground diversion pump station which is integrated into flood control channel maintenance roadway.
- Utilizes the existing municipal storm drain system to deliver flows to the park and minimizes force main construction.
- Specialized interconnected naturalized treatment cells consisting of alternating shallow wetlands and wetland ponds.
- Wetlands include specialized surface and subsurface wetland treatment elements utilizing specialized media for the growth of treatment bacterial biofilters.
- Naturalized treatment system design within the park designed so that existing active park areas are not lost, and aesthetics and passive recreation are enhanced.
- Restoration of an existing ephemeral lake within the park provides year round water storage and final polishing treatment with submerged media biofilters, submerged aeration, and wetland planters system.
- Restored lake serving as irrigation storage for park, eliminating potable water use for irrigation.