Urban Return Projects

Oso Barrier

The Oso Barrier is a water diversion system that has been in service since the 1979. Located adjacent to Oso Parkway and the Mission Viejo Country Club, the Barrier is responsible for intercepting more than 1 million gallons per day of water running through Oso Creek. The Barrier serves to restrict the urban runoff that has a higher concentration of pollutants from flowing into the downstream San Juan Basin. This intercepted water is pumped to the Oso Creek Water Reclamation Plant where it is blended with recycled water and then stored at the Upper Oso Reservoir for usage at golf courses, parks, and other irrigated areas.

Horno Basin

The Horno Basin is a water diversion system located on Horno Creek in the southern edge of Ladera Ranch. The basin is designed to mitigate storm flows with a retention basin so that these flows do not damage downstream communities. Horno is also designed to divert low flows through constructed wetlands for natural treatment which is then pumped into the District's recycled water distribution system for beneficial reuse. 

Dove Canyon Conservation and Water Recovery Project

The Dove Canyon Conservation and Water Recovery Project is an innovative diversion project that helps keeps urban runoff from reaching the natural habitat in Starr Ranch Sanctuary.

In operation since 2007, this one-of-a-kind project is in partnership with Trabuco Canyon Water District (TCWD) and Audubon Starr Ranch Sanctuary.  Each year, approximately 200 acre-feet of runoff water from Dove Canyon is diverted from Starr Ranch to SMWD’s Portola Reservoir and TCWD’s Dove Lake, both of which hold recycled water.  The project allows both water districts to gain about 200 acre-feet annually of recycled water, freeing up an equal amount of domestic water for customers to use.  The water is then treated and used to irrigate nearby parks and golf courses.

Before the project was implemented, delicate habitat along Bell Creek, located within the 4,000 acre Starr Ranch, had been disrupted by the invasion of non-native species due to year-round water runoff from Dove Canyon.  Today, the project is helping protect and restore this pristine area for future generations.