Prado constructed wetlands

The Prado Constructed Wetlands near Prado Dam enhance water quality by removing nitrate and other pollutants in the Santa Ana River water that flows to Orange County. These programs additionally allow OCWD and the U.S. Army Corps of Engineers to capture stormwater at Prado Dam for recharge in Orange County—providing a local water supply and saving millions of dollars each year. 

Habitat restoration

The least Bell’s vireo (vireo belli pusillus) is a small migratory songbird. OCWD’s vireo program has been one of California’s great environmental success stories. When the program began in 1986, there were only 19 vireo territories in the Prado Basin. By 2004, the vireo population in the Santa Ana River Watershed became the largest in existence. The most recent 2017 figures account for 549 vireo territories in the Prado Wetlands and 1,757 overall in the Ana Ana Watershed—the area along the Santa Ana River. OCWD has invested millions of dollars to create more than 800 acres (323.7 hectares; 3.2 square kilometers) of habitat for the endangered bird. Through these restoration activities, OCWD has brought the species back from the brink of extinction and successfully helped the vireo to flourish.

The Santa Ana sucker (catostomus santaanae) is a fish found in streams of the Santa Ana River Watershed; it has all but disappeared from other watersheds of Southern California. OCWD plays a major role in protecting this endangered fish. Since 1995, OCWD has been actively participating in the development of studies and programs to restore habitat needed for recovery of the species. The Santa Ana Sucker Conservation Team, a group of concerned public agencies from the Santa Ana River Watershed, along with the U.S. Fish & Wildlife Service and the California Department of Fish & Wildlife, are part of this endeavor. The conservation team’s efforts created the first successful Santa Ana sucker spawning habitat restoration in the watershed. 

Removing intruders

In addition to saving endangered species, OCWD works to restore habitats by removing nonnative invasive species that damage the balance of the plant environment. OCWD contributed $1 million to help create the Santa Ana Watershed Association (SAWA) to lead the removal of a water-guzzling, invasive plant from the watershed. Arundo donax is a fast-growing, nonnative reed that grows in dense thickets up to 20 feet (6 meters) tall. Removing it and replanting with native plants not only restores a more water-efficient natural habitat, but also conserves precious water supplies, saving 18,000 acre-feet (5.9 billion gallons; 22.2 billion liters) annually. OCWD must constantly monitor and remove this destructive species in order to rehabilitate and maintain endangered species habitat. 

Wetland bird tours

Birding tours of the Prado Constructed Wetlands are available every spring. Please visit the OCWD specialty tour page for additional information.