Contacts
 






Keyword Site Search







Prado Wetlands: A Watershed for Water Quality and Wildlife In the 1950's, when Mike Raahauge's father originally constructed ponds to attract waterfowl to the Prado Basin in Riverside County, California, few would have thought that Raahauge's duck hunting club--whose now diverse activities include hosting an annual western retrospective known as "The End of the Trail"--would be sited on the forefront of national water quality research. But Raahauge's Shooting Enterprises operate on land leased from a regional water district whose broad-reaching responsibilities include managing and protecting groundwater resources from the Santa Ana River watershed in downstream Orange County. The Orange County Water District (OCWD) is nearing completion of a three-year study whose results will help determine how to reconfigure and expand the wetlands of Prado Basin into quite possibly the largest wetlands developed for water quality and wildlife enhancement in the U.S. OCWD supplies about two-thirds of the water (about 310,000 acre-feet* per year) used by 2 million residents of Orange County, principally water from the Santa Ana River, which is the main source from which to replenish the large groundwater basin underlying Orange County. OCWD therefore utilizes various properties in the Santa Ana River drainage area for detention, settling, and percolation of surface waters into the groundwater basin. OCWD has shown the quality of Santa Ana River water is enhanced by diverting flows through wetlands and utilizes the Prado Basin as a water quality enhancement area. The Prado Wetlands is not a natural feature, but a wetland environment created behind Prado Dam when the U.S. Army Corps of Engineers (USCOE) constructed the dam to provide flood control for interests in the Santa Ana River watershed, which was then enhanced by hunting enthusiasts. "Mike Raahauge's dad knew a little something about habitat," said the USCOE's Ted Carr with a chuckle, referring to the resourcefulness of the avid duck hunter who built the original ponds. Though Prado Wetlands is a constructed wetlands, it is still subject to the regulatory influence of the USCOE and the US Fish and Wildlife Service (USFWS) regarding permitting and compliance with environmental mandates like the Clean Water Act (404 permits). For instance, Carr explained, "Within [its] flowage easement, the USCOE authorizes construction of levees, land changes, water diversions, and removal of plant material within critical habitat areas per Fish & Wildlife [regulations]." Accordingly, to use the area for water conservation and water quality improvement required OCWD to negotiate multi-party agreements that not only provide for the use of Prado Basin, but ensure protection of the environment. "The [USCOE] works with OCWD regarding their developments, [assessing] overall effects of development on the flood control basin from upstream activities--anything behind the dam," clarified Carr. Indeed, the water district's operations become a part of the oversight of other enterprises within the USCOE's purview--for instance, future enhancements at the shooting club. Because the recreation facility is sited in the midst of a protected environment, Landscape Architect Larry Ryan interfaced with all of the requisite agencies during preparation of the Master Plan of Raahauge's Shooting Enterprises. A principal of RJM Associates whose forte is park planning and design, Ryan called the required review process "a whole component" of the project and commented on the project as an "excellent example of sharing and juxtaposition through site planning and operations," referencing the "seamless interface [that is] the goal of Landscape Architecture." Ryan enjoys the "challenge of working . . . with professionals with specific knowledge to create a product whose total is greater than its parts," in this case "biological research and park-like, functional activities." *An acre-foot of water, which would cover a football field to a depth of one foot, supplies two families for a year. The Chemistry for Success Orange County's groundwater basin yields high-quality drinking water that meets all federal and state standards--for the most part without treatment before delivery to customers (water retailers). However, because the Santa Ana River is primarily of wastewater origin, nitrate concentrations approach the drinking water standard limit. OCWD is using water diversion and enhancement as a strategy to meet new standards established by the Regional Water Quality Control Board (RWQCB). Given that high concentrations of certain constituents found in wastewater could pose a particular threat to groundwater supplies in the RWQCB's jurisdiction, the regional regulatory authority is requiring reduced levels of nitrogen in wastewater effluent that is discharged into the Santa Ana River from 18 upstream treatment plants. But the cost to individual agencies to expand existing treatment facilities or construct new ones to comply with these more stringent regional regulatory limits would be quite high. So, as a regional entity, OCWD has been exploring ways to reduce nitrogen levels at a lower shared incremental cost--including natural means. Accordingly, nitrogen constituents are among the specific objects of scientific monitoring and study of water diverted through the ponds in Prado Basin . . . and of research in isolated cells constructed within those wetlands. Monitoring has confirmed that diverting Santa Ana River flows into the wetlands naturally enhances water quality--that is, that nitrate removal occurs through a natural process in Prado Wetlands. Plants, vegetation, and the soil layer at the bottom of the ponds are primarily responsible for "treating" the water. More effective in some locations than others, the wetlands "treatment" process has proved "impressive" in removing nitrates from Santa Ana River water, removing nearly all of the nitrate in the water and dramatically reducing its levels to well below current drinking water standards. In 1992, an intensive sampling program funded jointly by OCWD, California's State Water Quality Control Board, and a joint-powers authority known as the Santa Ana Water Project Authority specifically demonstrated nitrogen removal efficiencies up to 88 percent, with nitrate-nitrogen (the principal nitrogen component) consistently removed to non-detectable levels. While more research was needed, preliminary studies also showed that the process is seasonal, with less dramatic results during the winter. Still, during the summer months, in the distance that the water travels through the ponds, it exits the wetlands with non-detectable levels of nitrate, converted into a harmless gas as it passes through the series of wetland ponds. Subsequent research, co-funded by the National Water Research Institute, whose mission is to identify and support research that will lead to improved water quality and supply, involves a three-year study. This research on the effects of various plant species and hydraulic resident times on nitrogen removal has involved construction of isolated test cells with "mesocosms" of specific wetlands vegetation. Currently, the University of Notre Dame is using advanced technologies to "fingerprint" the water's characteristics before and after it travels through the wetlands, while scientists from the University of California (UC) Berkeley compare various types of vegetation and different retention times to determine which vegetation achieves the best results. Hydraulic resident times ranging from 1 to 14 days are being evaluated. Soon to be completed, this study will ensure that the nitrogen removal process in the wetlands operates at maximum efficiency. OCWD's project manager, water resources engineer Craig Miller, has been working with Alex Horne, Ph.D., an environmental engineer from UC Berkeley to monitor various vegetation regimes for effective removal of nitrites, nitrates, and nitrogen. "The mesocosm plantings were created from existing vegetation. We [use the data] to develop a scenario or model of why the wetlands naturally denitrify the water so we can plan how to expand," said Miller. So, why the chemistry lesson? Leaping Boundaries Dr. Horne, who has earned a reputation for water, lake, and estuary clean-up and leads the UC Berkeley research, says, "We have to make wetlands work harder," says Horne, who is studying the native aquatic vegetation, particularly cattail and bulrush, for wildlife food and habitat value as well as nitrogen removal efficiency. The funders of the research would appear to agree. Ron Linsky, Executive Director of the National Water Research Institute, said "There's no such thing as 'pristine.' Where you have urbanization and people, you have modified environments . . . ," calling the use of constructed wetlands to enhance water quality through natural means at Prado Wetlands "the premier project of its kind in the United States. That's why we funded the research." Citing usefulness and biodiversity as the two operative reasons for environmental projects, Horne said, "This [Prado Wetlands] is not a restoration project. Though a purist would let wetlands return [to a natural state], [in order] to produce more healthy birds, animals, vegetation, and clean water for human consumption, we have to make its system more efficient than nature itself. . . . It's all interrelated. For instance, permanent wetlands is an inefficient environment for wildlife, but good for nitrate removal. In seasonal wetlands, [scientific research helps] adjust the 'hydro period' or wet time to allow for 'dry-out' in spring and summer [to make the habitat] really productive for insects . . . insects of all kinds . . . for birds with different sized beaks. We have to determine how to make the wetlands seasonally productive for birds--they need the proteins [from the insects] twice a year for egg production." Notwithstanding, Horne believes that in general Landscape Architects and others who have a concept for a project can not only learn from researchers, they can direct the study of aspects which will lead to the scientific ability to support their aesthetic visions. But, according to Horne, "Understanding between disciplines is needed . . . if scientific research is to result in design of really productive environments. . . . if Landscape Architects want [an environmental project to happen the way it's envisioned, effective interface between disciplines is needed," said Horne, who admits he was motivated to become an engineer only after discovering that as a research biologist he was not positioned to implement remediation projects. By extension, the implication is that Landscape Architects who want to be involved in environmental projects may have to re-orient their thinking for greater involvement in wetlands and other habitat remediation projects. OCWD has not finalized its expansion plan nor the extent to which it will utilize the expertise of Landscape Architects, according to Miller. In any case, Landscape Architects may not have a free hand in selection of wetlands vegetation, though Horne suggests, as in many things, the operative questions to ask revolve around the limiting factors: Can [science support] this aesthetic vision? With what results? What are the trade-offs? Horne cites the example of seasonal wetlands where the dry periods have an associated release of heavy metals, though Horne says it is possible "to grow enough plant material to 'dilute' [heavy metals] with . . . a productive organic material like peat [which forms from submerged layers of decaying plant material]." Study will determine ratio of permanent and seasonal wetland areas needed to accomplish both water quality (usefulness) and the wildlife habitat (biodiversity) goals. In addition to nitrate removal properties and how many insects the different stands of vegetation will support, Horne calls attention to habitat value of plants the question of which plants birds like to nest in. For instance, [least Bell's] vireos nest in March. Furthermore, Horne has discovered cultural and aesthetic value of certain plants other factors that pressure design: "Submerged species may be just as good [for nitrate removal], but are not as pretty. . . We need reeds. . . People expect to see reeds." From the researcher's theoretical vantage point, the project's potential for official and peripheral expansion is huge. Though OCWD currently can't isolate different ponds by "hydro period," except for the test cells, the new system will allow a dry pond next to a wet pond, effectively creating the ability to establish a permanent wetland for water quality treatment next to a seasonal wetland for environmental protection and mitigation. Horne indicates there are approximately 6,000 acres of potential wetland habitat in the area, though 4,000 acres may be recognizably "wet" only to experts and not are all owned by OCWD. Of these, OCWD has targeted 800 acres, roughly one-third of the nearly 2,500 acres of land it owns within the Prado Basin watershed, for the entire project. This includes about 35 acres for wildlife and least Bell's vireo habitat, to be created by allowing selected ponds to revert to natural vegetation and by constructing islands for waterfowl nesting in accord with USCOE and USFWS requirements. The USCOE's Carr, who began his career in parks and recreation, also sees value in Landscape Architects' involvement in environmental projects, "especially in review and balancing aesthetics" and projects Landscape Architects' "roles in native planting, replanting, mitigation and wildlife areas." While the water district's permit with the USCOE currently allows half of the base flow of the Santa Ana River to meander through 500 acres of the Prado Wetlands, as yet the modifications to the existing system which have increased the capacity of the ponds and enhanced the effectiveness of nitrogen removal accommodate only one-third of the river's volume. To increase the percentage of river water that will flow through this natural treatment process, OCWD is considering building a second pond system on an upstream parcel. With the proper future permits, the proposed 300-acre expansion would physically allow the entire flow of the river to be diverted through the natural wetlands treatment system. Combined, the two pond systems would cover about 800 acres and, in terms of their treatment capacity of 15,000 acre-feet yearly, comprise the largest constructed wetlands in the nation. To date, approximately $300,000 has been expended to develop the Prado wetlands, and future costs are expected to bring the total to some $5 million. But the program also saves money. By participating with OCWD in the constructed wetlands project, waste dischargers upstream may also avoid some $200 million in associated costs of upgrading their treatment facilities to meet revised water quality requirements. As a member of the water community that benefits from the research of the OCWD, the former president of the Orange County Water Association, a local organization of water entities, James A. Van Haun said, "The Prado Wetlands project holds great promise nationwide as an example of a nitrate removal process incorporating natural systems. The results thus far have been very encouraging." Indeed, the combined water conservation, water quality improvement, and wildlife habitat restoration aspects of the Prado Wetlands project have already earned OCWD the 1993 Theodore Roosevelt Environmental Award from the Association of California Water Agencies (ACWA)--for addressing environmental concerns in the achievement of project goals, and the 1994 "California Water Policy IV Conference Award"--honoring those who have advanced water policy by forging new relationships. Furthermore, the wetlands project is a crucial project in the comprehensive groundwater management plan which gained the water district ACWA's 1994 Water Management Gold Star Certification for conservation and efficient use of water. OCWD's General Manager William R. Mills, Jr., who holds the distinction of being quoted as "an unabashed advocate" of reclamation in the National Geographic Society's 1993 Special Edition on Water: The Power, Promise and Turmoil of North America's Fresh Water points out that the Santa Ana River, a river that used to be dry in summer, now flows year-round with a renewable resource suitable for aquifer replenishment--establishing a blueprint for solving the water supply and distribution problems in this country. Mills, who co-authored California's Water Recycling Act of 1991, cites "streamlining the process of permitting, constructing and operating the needed recycling facilities . . . ." as the solution to the institutional and regulatory impediments to reclamation ("Enhancing California's Future Through Recycling Wastewater"). Certainly, effective remediation and mitigation programs help remove the obstacles to future phases. A Watershed for the Future Prado Wetlands figures prominently in OCWD's future water conservation and water quality plans, as a factor in negotiations to secure additional water conservation storage behind Prado Dam, as a demonstration site for future regulation of dairies whose runoff fouls water resources, and as the site of education and research. The dramatic removal of nitrogen documented in effluent-laden water from Santa Ana River water that has flowed through Prado Wetlands has prompted the RWQCB to propose a demonstration project to divert the wash water from selected dairies in western San Bernardino and Riverside Counties through Prado Wetlands. Although the regional authority has set limits on salt and nitrogen concentration in wastewater treatment plant discharges, dairies have so far escaped stringent regulation in the Santa Ana River drainage area. Because the Santa Ana River and its tributaries receive dairy runoff, the environmentally sound strategy could effectively halt the degradation of groundwater attributable to dairy disposal practices in two upstream counties. In a related cooperative effort with environmental agencies, OCWD has negotiated an agreement with the USCOE for permanent storage of seasonal stormwater behind Prado Dam. The agreement calls for gradual increases in storage elevations over a period of several years, enabling the District to conserve millions of dollars worth of water that would otherwise be lost to sea. As a mitigation measure, specific increases in habitat areas to be set aside for the least Bell's vireo, an endangered songbird, has been tied to each incremental increase in conserved water storage. OCWD's protection of least Bell's vireo habitat has proven wildlife benefits, to such an extent that water conservation planning has been accelerated on the basis of its progress. OCWD has converted 124 acres to vireo habitat as part of an emergency agreement in 1991 and will expand it to 228 acres. Additionally, OCWD has contributed $1 million as mitigation for the vireo. This money is being used for habitat enhancement in the Santa Ana River watershed. In part due to an OCWD-funded biological monitoring program, the least Bell's vireo' population has increased by more than 700 percent since 1986. In addition, OCWD has initiated discussions with state and general environmental authorities regarding a future national wetlands demonstration and research center in Prado Basin. Such a center, located in the nation's largest constructed wetlands area, would provide a nucleus for broad-based research in the biological treatment of surface water supplies--at once a physical and an informational watershed, according to Funk & Wagnalls, "a decisive turning point, profoundly affecting or altering what follows it." ---------- All illustrations provided courtesy of the Orange County Water District. Photographs by Donna Moniz Davis, except aerials and as noted. Note: Other captions will be written based on production staff's selection of photographs. In a landmark agreement between OCWD, the USCOE, and the U.S. FWS, the water conservation level behind Prado Dam was raised, nearly doubling the amount of valuable water that can be stored. During the first weekend of the new agreement, OCWD captured and saved an additional #3.2 million worth of storm water behind the Dam. The cooperative agreement between agencies was the culmination of years of cooperative efforts to enhance the water conservation and environmental values of Prado Basin, breeding grounds of the least Bell's vireo, and endangered songbird. The original agreement between the three agencies allowed the District to conserve approximately 12,060 acre-feet, with a goal of raising the level within the next few years. However, because of the success of the vireo remediation program, the original plan was accelerated, allowing the district to store up to 25,750 acre-feet behind the Dam. Horne considers . . . the significance of these results. . . . to evaluate the efficiency of various plants and "wet season" periods. Horne considers . . . the Santa Ana Water Project Authority (SAWPA) [Prado Wetlands} is a good model, a very good example of cooperative solutions to difficult projects. -By routing water through a network of constructed wetland ponds behind Prado Dam, OCWD has devised a cost-effective, natural process that reduces nitrate levels to well below current drinking water standards. -"We have to make wetlands work harder," says Horne, who is studying the native aquatic vegetation, particularly cattail and bulrush, for wildlife food and habitat value as well as nitrogen removal efficiency. -OCWD successfully negotiated multi-party agreements that provided for the use of Prado Basin for water conservation and water quality improvement, while ensuring protection of the environment. -OCWD is also supporting studies of natural nitrate removal in constructed wetlands, such as the duck ponds on district property behind Prado Dam. OCWD believes the quality of Santa Ana river water is enhanced by diverting flows through the wetlands. -The Prado wetlands project utilizes nature's own biological processes to remove nitrogen from Santa Ana River water. -A test pond study now underway will reveal the most effective types of vegetation. -Duck pond above Prado Dam serve as a natural purification system that removes nitrates and other contaminants from Santa Ana River water. -A network of ponds in Prado Basin provides a natural water treatment system that removes excess nitrogen from Santa Ana River water. - It seems that Mother Nature has created a natural process for treating wastewater discharge into the Santa Ana River. -Over the past three years, OCWD has altered structures in the Prado Basin constructed wetlands to increase flow rates and enhance nitrate removal, redirecting water through this network of ponds to improve hydraulic capacity from 20 cfs to 60 cfs and gathering information from which to plan future improvements to boost the system's capabilities to more than 100 cfs. Projected to be operational in 1996, expanded pond areas could ultimately accommodate the river's entire base flow. -Though the current base flow of the Santa Ana River varies from about 60 cfs in summer to 150 cfs during the winter wet season, by the year 2010, the range is expected to be 140 cfs to 200 cfs. The completed wetlands project will have a hydraulic capacity of 200 cfs to accommodate all of the increased future base flows, with the exception of storm flows which, according to a different agreement with the USCOE, will not be diverted to the ponds but will be captured and stored in Prado Dam. -The results of the wetlands "treatment" process have been impressive in removing nitrates from the Santa Ana River, which contributes the majority of the annual recharge water for the Orange County groundwater basin. This improved water quality is a benefit for water consumers who rely on water from the groundwater basin, and is a natural alternative to more costly treatment processes. -OCWD has found that nitrogen levels drop dramatically when Santa Ana River flows are diverted through a network of reconstructed ponds on District land behind Prado Dam in Riverside County. -About half of the Santa Ana River's flow is currently diverted through the ponds, and OCWD plans eventually to route the entire river flow through constructed wetlands. -Its success as protected least Bell's vireo habitat provides a proven wildlife benefit. An economical way to treat wastewater discharged into the Santa Ana River. $ savings of a natural system with increased effectiveness, decreased costs, habitat and recreational benefits At first an environmental requirement, habitat mitigation has become a way to leverage the expansion of the wetlands program. Habitat program success and accelerated progress there is a leverage/negotiation tool

Search Site by Story Keywords



Related Stories



June 17, 2019, 8:40 am PDT

Website problems, report a bug.
Copyright © 2019 Landscape Communications Inc.
Privacy Policy