Prado constructed wetlands

OCWD owns approximately 2,150 acres of land in the Prado Basin, located behind Prado Dam, including about 465 acres of constructed wetlands – the largest constructed wetlands on the West Coast. The wetlands serve as a natural pre-treatment system, improving Santa Ana River water quality before it is captured and recharged into the groundwater basin. The Prado Basin is also home to critical habitat and endangered species like the least Bell’s vireo.

Wildlife management within the Prado Basin

The Prado Basin is home to hundreds of plant and animal species, including over 250 types of birds. OCWD’s habitat restoration efforts have also led to increased populations of several endangered species.

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. Today, there are more than 760 vireo territories in the Prado Wetlands. OCWD has invested millions of dollars to create more than 800 acres 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.

Invasive species removal

In addition to saving endangered species, OCWD works to restore habitats by removing nonnative invasive species. OCWD works with the Santa Ana Watershed Association to remove Arundo donax, also known as giant reed, from the Santa Ana River watershed. Arundo is a fast-growing, nonnative plant that can grow 4 inches a day and up to 33 feet tall. It displaces native riparian vegetation, reduces habitat diversity, provides poor habitat value for wildlife, and can increase wildfire risk. It also consumes large amounts of water. Removing Arundo and replanting native vegetation helps restore healthier, more water-efficient habitat, supports endangered species recovery, and improves the ecological function of the river corridor. Management of Arundo and other invasive vegetation is required under permits and agreements with the U.S. Fish and Wildlife Service, U.S. Army Corps of Engineers, and California Department of Fish and Wildlife.