South Coast Water District Launches Innovative Water Harvesting Facility

The project taps a new water source, reduces urban run-off, improves water quality, and converts an irrigation system from potable to recycled water.

In a collaborative effort with the County of Orange and the City of Laguna Beach, South Coast Water District is constructing an innovative water harvesting and treatment facility that will have multiple bangs for the buck.

The Aliso Creek Water Runoff Recovery and Reuse facility will treat water harvested from Aliso Creek as well as tertiary-treated wastewater to lower salts in a recycled water irrigation system. Between 300,000 to 800,000 gallons per day of urban runoff in the creek will be treated based on customer demand and available creek flow.

This project taps into a new source of local water supply, reduces poor quality urban runoff from reaching nearby Aliso Creek Beach, and increases water conservation by converting an irrigation used on a local golf course from potable water to improved quality recycled water.

“We are very excited about this new water supply from a local source, and we like the fact that the project will contribute to improving water quality in the area of Aliso Creek Beach,” says SCWD General Manager, Betty Burnett.

Urban runoff draining to Aliso Creek and ultimately to the ocean at Aliso Creek Beach will be intercepted to reduce the amount of poor quality “urban drool” from reaching this premier beach in South Laguna.

The District received $500,000 in Orange County Proposition 50 funds and a pledge from the City of Laguna Beach for $25,000 in support of the project. The County of Orange also offered $50,000 in support funding toward the costs of construction of the project.

“The district’s Aliso Creek project is an excellent example of how Proposition 50 funding is being applied to benefit the community multiple times over,” said Marilyn Thoms, manager of the watershed management section for the County of Orange and Program Manager for Proposition 50 funding programs for south Orange County.

The district has been studying alternatives to improve the quality of their recycled water supply that has increased in total dissolved solids and salts sometimes up to 1,300 parts per million (ppm), a high level that can occur in coastal wastewater systems.

South Coast Water District was one of the first agencies in Orange County to build and operate a recycled water system in the early 1980s for irrigating larger landscaped areas. As the percentage of imported water from the Colorado River increased over the years, the local water supply rose in mineral and salt content (“hard water”). These natural salts pass through the wastewater treatment process and make the district’s recycled water higher in salinity than is preferred by local recycled water customers.

Dudek engineers provided the district with the planning, design, and implementation services of an ultrafiltration (UF)/reverse osmosis (RO) membrane treatment facility to remove the salts from the creek supply and tertiary treated wastewater supply from the coastal treatment facility.

Bob Ohlund, Dudek’s vice president for infrastructure and water resources, notes, “Our engineers focused on designing an economical solution to providing a membrane treatment facility that would successfully reduce the salts by selectively drawing water from the creek and operating in tandem with the coastal wastewater treatment plant.”

The new treatment facility will reduce the TDS to an average of 800 ppm, much more compatible for landscape irrigation, especially for the more sensitive uses such as golf courses. In addition to increasing its water supply, the District’s goal is to immediately conserve 50 acre-feet per year of potable water usage at a nearby golf course by converting irrigation to the higher quality recycled water supply and future expansion of the recycled water system.

The district’s permits to use water from Aliso Creek require monitoring of potential environmental impacts and a sufficient bypass flow rate (4.2 cubic feet per seconds) to ensure protection of fish and plants and continued flows into the lagoon at the mouth of the creek.