In May, WMC sponsored a three day field trip of two of Southern California's largest watersheds - the Santa Ana and the Santa Margarita - to learn about a variety of land use issues, management challenges, and innovative problem-solving. Credit for organizing this ambitious effort is owed to Terry Kaplan-Henry of the WMC Board, Valerie Vartanian of The Nature Conservancy, Vi Slade of
The East Valley Resource Conservation District (RCD), Shelly Lamb of the Riverside-Corona RCD, and Judy Mitchell of the Mission RCD, along with 14 other co-sponsoring water districts, agencies and local districts. This field trip was the second time WMC has explored Southern California's watersheds for a field tour, having visited the upper Los Angeles Basin in 1990.
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The Santa Ana River is the largest stream system in Southern California. It begins high in the San Bernardino Mountains and flows over 100 miles southwest to the Pacific Ocean at Huntington Beach. Its watershed receives an average annual rainfall of about 13 inches and covers 2650 square miles of widely varying terrain including parts of San Bernardino, Riverside, and Orange Counties. It is home to more than 4 million people. Under natural conditions, the river would be an intermittent stream with high run-off in the winter and spring, and little or no flow in the summer months. Now natural flows are supplemented with highly treated wastewater effluent coming from several treatment plants. As the river and its tributaries flow toward the sea, streamflow recharges 29 groundwater basins. Groundwater is used for agricultural, municipal, and industrial supply. Following municipal and industrial use and treatment, the water is returned to the river as effluent, being used an estimated 2.2 times before reaching the sea. The quality of the effluent returned to the river is closely controlled by the Santa Ana Regional Water Quality Control Board to assure that the supply is protected for downstream beneficial uses.
In contrast to the Santa Ana, the lower reaches of the Santa Margarita River are mostly rural with the mainstem and many of the tributaries undammed. The watershed encompasses 740 square miles and has an average annual rainfall of 14-15 inches per year, with some areas receiving over 20 inches per year. Primary land use in the lower watershed includes the Camp Pendleton Marine Corps Base and the Fallbrook Naval Ordnance Center. The upstream watershed is developed with cities, housing, and agriculture dominated by vineyards and avocado and citrus orchards.
Concerns in the Santa Margarita watershed today include flooding, water quality, water supply, and environmental uses. After the 1993 floods that caused millions of dollars in damage to the area, there has been an emphasis on protection against future floods. Water quality issues focus on sediment, nutrients (especially nitrates), and salts. Environmental concerns include preservation of wildlife habitats, eradication of the exotic weed Arundo donax, and public access to open spaces. The watershed already contains three large ecological reserves and local groups are looking into acquiring fragments of riparian corridor to create large, intact habitat patches.
Our first tour stop was in the headwaters at Big Bear Dam, flowing over the spillway for the first time in 4 years at a rate of 450 cfs. Constructed in 1911-12, this multiple-arch dam created a 2500 acre lake with a capacity of 73,000 acre feet. Average annual precipitation at the dam is 34 inches. Big Bear Lake is a popular recreational getaway accommodating 6-8 million visitors each year. Increased development in the watershed and recreation on the alpine lake have stimulated its eutrophication. Through restoration projects on the major tributaries and community education regarding shoreline erosion protection, Big Bear Municipal Water District (MWD) officials are trying to get a handle on water quality issues by taking a watershed management approach. They're working closely with the East Valley RCD on these watershed projects. Watershed-wide, the Santa Ana Watershed Association of the five local RCDs seek "to promote a healthy Santa Ana watershed for both wildlife and people."
We visited Stanfield Marsh, a cooperative effort between Big Bear MWD and the Natural Heritage Foundation to create a wildlife preserve. Cal Trans grant money was recently acquired to improve the area by creating a parking area, planting native trees and shrubs, and constructing an informational gazebo and boardwalk. The marsh provides habitat for endangered species and supports thousands of migrant and resident waterfowl.
Dinner at the Northwoods Resort on Big Bear Lake featured a talk by Dr. Neil Dubrovsky of the US Geological Survey (USGS) on the National Water Quality Assessment Program (NAWQA) study recently completed in the San Joaquin-Tulare Basins and the new one that is beginning in the Santa Ana River watershed. To quote a USGS project poster on water quality in the Santa Ana Basin, "The use of reclaimed water and a subsequent increase of nutrients and dissolved solids in water supplies have been identified as the primary water quality problems in the Santa Ana Basin".
After watching an informative video on the Santa Ana watershed project and Seven Oaks Dam, we went to visit the US Army Corps of Engineers' dam construction site on Bear Creek. The purpose of the Seven Oaks Dam is flood control, although conservation efforts are underway to use this storage facility for drinking water in the future. Due to increased development and associated impervious surfaces in the watershed, runoff must be contained to prevent the heavy economic damages associated with increased downstream flooding.
A nearby mountain is being leveled to supply materials for the project. A system of conveyer belts moves the crushed rock from the source to the dam site. At present, the dam is increasing in height by 1 foot every 20 hours, and will be completed in July 1999 with a maximum capacity of 145,600 acre feet. The cost of construction is being shared by the federal government (about 60%), Orange County (about 30%), and Riverside and San Bernardino Counties (about 10%). Speakers from the San Bernardino Flood Control District, Southern California Edison, and San Bernardino MWD shared perspectives on flood control facilities, hydroelectric generation, and groundwater pumping, recharge, and contamination, respectively.
Downstream of Riverside, we stopped for lunch at the 1500 acre Hidden Valley Preserve, managed by the Riverside County Park District.Through the cooperative efforts of several agencies and citizen groups, the Hidden Valley Wetlands Enhancement Project was born, providing the community with recreation, education, research, wastewater treatment, reclaimed water reuse, environmental enhancement, wildlife habitat creation, and water quality improvements. This 70 acre project constructed and restored 15 wetlands, and installed an array of flow collection and distribution structures, piping, and control gates. A variety of sensitive and endangered species are dependent on the wetland habitat. By controlling the exotic plant Arundo donax and subsequently revegetating with native plants, the enhanced wildlife area has a higher habitat value. Wetland ecosystems are effective nitrogen removal systems, while recharging local groundwater and saving city residents millions of dollars.
The complexity of water rights for the Santa Ana's ground and surface waters was described concisely by Steve Mains, the river's Watermaster. Our last visit before dinner was at the Prado Flood Control Basin above Prado Dam near Norco. Richard Zembal from US Fish and Wildlife Service and Brian Baharie of the Orange County Water District shared views on endangered species programs, bank erosion mitigation, water quality, constructed wetlands, urban and agricultural issues, and flooding. We listened to an endangered least Bell's vireo (Vireo bellii pusillus) sing. This small, olive- gray migratory songbird occurs almost exclusively in riparian woodland habitats and was listed as endangered in 1986, due primarily to the extensive loss of its habitat and brood-parasitism by the non-native brown-headed cowbird (Molothrus ater). Management of the vireo's habitat and removal of the brown-headed cowbird have resulted in significant increases in vireo populations and reoccupation of breeding habitat. Constructed wetlands in the area have contributed to wildlife habitat while removing nitrogen from the predominantly wastewater flows and recharging local groundwater in the process.
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Background for our Santa Margarita tour was provided on the bus by Larry McKenney, water resources attorney with Camp Pendleton. Viewing the melodramatic 1954 film "The Fallbrook Story" by Frank Capra, we were offered one perspective on the long-lived battle for water rights in this watershed. At the Fallbrook Public Utilities District office, Federal Watermaster Jim Jenks presented a history of the Santa Margarita River's water rights issues. Then we were off to Camp Pendleton, the only west coast Marine Corps Base with an amphibious training facility. Its paramount importance to Marine training was described by Mike Collier of the Base. Dedicated in 1942, this 125,000+ acre military site, with its varied terrain and 17.1 miles of shoreline, is also home to 17 proposed and listed endangered species. The Base is entirely dependent on the property's own ground water for its water supply, so water quality and water rights issues are very important to it, according to Larry Carlson, Water Resources Manager.
Stop 1 was a visit to the coastal nesting colony of the California least tern (Sterna antillarum browni), which is protected by the Marines through fencing, posted warnings and predator control. This endangered migratory seabird is vulnerable to predation due to nesting in typically flat, open areas with little vegetation, and increased coastal development. Base wildlife biologist Slader Buck explained the Marine's management strategy for the tern, which has proven quite successful with 600 birds counted in 1997.
Because Camp Pendleton occupies the lowest portion of the watershed, it receives all of the watershed impacts. The 1993 flood, the largest one since 1916, caused an estimated $36-$71 million damage on the Base, washing out bridges, railroad tracks, and roads and depositing 300,000 cubic yards of sediment on the Air Base and other facilities. Road signs from Temecula were found in the estuary. To protect their facilities, a flood control levee is being studied by the Public Works Office to protect the Base's facitilies in the flood plain. Extermination of exotic species such as Arundo is difficult since the pest is constantly washing in from upstream. There is a need to focus on control in the upper watershed first. Camp Pendleton is involved in promoting watershed planning efforts to prevent continued problems, such as the former Santa Margarita River Watershed Management Program and a watershed-wide stormwater permitting system. Mission RCD has helped implement many of the watershed projects on the Base. Our final stop at Camp Pendleton was at Lake O'Neil, a popular campground, where recreation issues were discussed.
We next went to San Diego State University's Santa Margarita Ecological Reserve located near Temecula. According to station director Sedra Shapiro, the reserve was established in 1962, encompasses 4,235 acres, and 5 miles of the river's gorge. It lies in the chaparral/coastal sage scrub/oak woodland vegetation zone of southern California and is dedicated to teaching and research in the field sciences. Looking over the deep gorge of the Santa Margarita River, researchers discussed the hydrology of the area, a proposed fire management plan, and management for sensitive species.
Our final stop was the 8,250 acre Santa Rosa Plateau Ecological Reserve. The reserve is a cooperative management project of The Nature Conservancy, the Riverside County Regional Park and Open-Space District, the California Department of Fish and Game, the U.S. Fish and Wildlife Service, and the Metropolitan Water District of Southern California. Located at the southern end of the Santa Ana Mountains, the rolling topography reaches elevations over 2,000 feet. Several basalt-capped mesas are scattered along the edges of the Plateau where some of Southern California's last vernal pools can be found, supporting fairy shrimp, wintering waterfowl, acres of spring wildflowers, and several species of endangered plants. Approximately 3,000 acres of rolling native grassland is widely regarded as the finest remaining bunchgrass prairie in the state, including the last reproducing Englemann oaks in the region. Native vegetation is being managed with prescribed fires and removal of non-native species, accordingto our enthusiastic speaker, Rob Hicks of the Regional Park District.-
