By James Vanderbilt, Orange County Water District (OCWD) Director
The 2018 World Wetlands Day (Feb. 2) theme was “Wetlands for a sustainable urban future.” The OCWD owns, operates and has developed the Prado Wetlands—the largest constructed wetlands on the west coast of the United States. OCWD knows the value of wetlands and the following article illustrates the impact of wetlands upon our local healthy and sustainable water supply.
Commercial bottlers often claim to have a monopoly on providing drinking water from environmentally purified sources. The local water district that supplies West Anaheim residents can share in that claim thanks to one of the largest constructed wetlands only a few miles away. OCWD manages the Orange County Groundwater Basin that provides 75 percent of the drinking water to West Anaheim and surrounding areas. OCWD uses the Santa Ana River water as a primary source to refill the groundwater basin, but the river flow, especially during non-storm seasons, consists primarily of highly-treated wastewater from upstream communities.
The Prado Basin, located in the upstream portion of Prado Dam in Riverside County, contains a system of 50 actively-managed wetland ponds on a 465-acre site.
A permit from the U.S Army Corps of Engineers allows approximately half of the river’s flow (about 80 cubic feet per second), which downstream becomes part of Orange County’s water supply, to be diverted through the Prado Wetlands. This followed research in the early 1990s that determined the wetlands function as an effective and natural treatment process that significantly removes nitrate in the water.
Nitrate is one of the most common and widespread contaminants in groundwater supplies. Elevated levels of nitrate in water supplies originate from fertilizer use, animal feedlots, wastewater disposal systems, and other sources. Plants and bacteria break down nitrate, a process that cleans up surface water before it percolates into groundwater. Nitrate removal at a conventional treatment plant would cost approximately $15 per pound, compared to about $0.85 per pound using the natural wetlands process. The wetlands currently remove nearly 175 tons per year from the Santa Ana River.
The wetlands project allows OCWD to improve water quality beyond regulatory requirements. By taking this proactive and innovative approach, OCWD improves groundwater quality, enhances the environment and minimizes treatment costs. In the late-1990s, the District reconstructed its wetlands to maximize the capability to treat river flows and to improve operational efficiency.
In addition to water quality, the wetlands provide an opportunity for native habitat to thrive and an abundance of plant and animal life can be found in this productive and rare ecosystem. Limited wetland tours take place each year during the spring and early summer and are scheduled upon staff availability. One might see a number of American White Pelicans, Great Blue Herons, Great Egrets, and more. Visit https://www.ocwd.com/contact-us/book-a-tour/ (click on Specialty tours) to learn more and reserve a spot.
James Vanderbilt is a council member of the City of Anaheim and represents Division 9 of the Orange County Water District. For more information, visit www.ocwd.com. Contact Director Vanderbilt at jvanderbilt@anaheim.net.
