The U.S. Environmental Protection Agency’s (EPA) Water Infrastructure Resiliency and Finance Center, in collaboration with the...
New Wetlands Used to Naturally Treat Santa Ana River Flows
The State Water Resources Control Board has selected the Orange County Water District's (OCWD) "Expansion of Prado Wetlands for Treatment of Santa Ana River at River Road" for Proposition 13 grant funding at the requested level of $1.2 million.
OCWD already manages 460 acres of constructed wetlands, the largest wetlands in Southern California, behind Prado Dam to provide natural water treatment for the Santa River flow. The new wetlands will be constructed in the flood plain of the Santa Ana River, upstream of both the River Road bridge crossing and OCWD's current wetlands. Expected completion of the project is early 2006.
The $1.2 million grant will be used for land preparation and habitat improvement, environmental work, wetlands design and operating expenses and earth moving work.
"This funding will benefit the environment and Orange County residents who rely on the Santa Ana River as a major source of drinking water. Not only will the expanded wetlands provide additional habitat and protection for the endangered least Bell's vireo songbird, it will provide more area for recreational activities and, most importantly, improve the quality of water in the Santa Ana River, which is the major source of water for Orange County residents," said OCWD Board President Denis Bilodeau.
This large wetlands environment in Southern California is host for thousands of waterfowl and other birds transiting the Western flyway. The new wetlands will naturally treat the other half of the Santa Ana River flows at a cost of 50 cents per milligram (mg) as opposed to mechanical treatment at a rate of $15 per mg.
The wetlands treatment provides natural nitrate removal before it travels on to Orange County for recharge into a large groundwater basin. The project, supported by the Santa Ana Regional Water Quality Control Board also meets their objective for nitrate-nitrogen of 3 milligrams per liter (mg/L). Wetlands treatment reduces nitrate-nitrogen levels from around 10 mg/L to anywhere from less than 3 mg/L to undetectable.