San Mateo Creek Watershed Profile

SAN MATEO CREEK WATERSHED PROFILE http://wrpinfo.scc.ca.gov/watersheds/sm/sm_profile.html Introduction The San Mateo Creek (SMC) watershed covers approximately 139 square miles of relatively undeveloped terrain. The majority of the SMC watershed's drainage area lies within western Riverside and northwestern San Diego Counties, with approximately 20% within the boundary of southeastern Orange County (Jorgensen, et al., 1971; Feldmeth, 1987). San Mateo Creek is one of the last undammed streams in southern California. The mainstem of the San Mateo Creek is over 22 miles long and has four main contributing tributaries: Cristianitos Creek, Talega Creek, Tenaja Creek, and Devil's Canyon (USFS, 1999b). Other contributing drainages within the watershed include Gabino Creek, La Paz Creek, and Cold Spring Creek (PCR et al., 2001). The SMC mainstem flows in a southwestern direction before reaching the Pacific Ocean just south of the City of San Clemente. The SMC watershed drains portions of the Santa Margarita Mountains, Sitton Peak, and the western slopes of the Elsinore Mountains. Cristianitos Creek, the main tributary, joins the mainstem approximately three miles inland from the coast and accounts for 29 square miles of the total watershed (Jorgensen, et al., 1971). The watershed contains two distinct topographical regions: the upper and the coastal. The upper region lies mostly within San Mateo Canyon Wilderness in the Cleveland National Forest. Its lower reaches run through Camp Pendleton Marine Corps Base and San Onofre State Beach. The upper mountainous drainage area consists mostly of the rugged, steep sloped, Santa Ana Mountains, which are bisected by intermittent streams. In the northern region of the watershed, these ridges and mountain peaks rise to an elevation of over 3,576 feet above mean sea level (MSL). The Santa Margarita Mountains form the eastern and southern boundary to the upper basin and have elevations of up to 3,189 feet above MSL. The coastal region contains a wide alluvial valley formed by San Mateo Creek and its major tributary, Cristianitos Creek. The lower San Mateo Creek Valley is approximately 1 mile wide by 2 ½ miles long, and consists of mostly flat alluvial terraces. The creek consists of a wide, braided channel and flood plain of up to 851 feet wide. The San Mateo lagoon, a blind estuary protected from the Pacific Ocean by a sandbar, is located at the mouth of the San Mateo Creek. This estuary contains dense wetland vegetation and is breached only after heavy storms (Feldmeth, 1987). Land use within the SMC watershed is primarily classified as open space. By the 1920s, the lower SMC watershed and the lands between the cities of Oceanside and El Toro were subsumed into the vast Rancho Mission Viejo. In 1942, the U.S. Department of Defense purchased the southern half of Rancho Mission Viejo and a large section of the lower drainage basin became part of the Camp Joseph Pendleton Marine Corps Base. The Cristianitos Creek sub-watershed in the northern part of the lower watershed remained in private ownership, primarily by the Rancho Mission Viejo Development Corporation. Small islands of private property also remain in the upper San Mateo drainage of the Cleveland National Forest and the Experian (formerly TRW) research facility located within the Talega Canyon drainage basin. One of these inholdings, located on the upper western divide of the drainage area, was developed into the Carillo residential community, which contains approximately 50 homes with horse facilities. The majority of the Upper San Mateo Creek watershed lies in the Cleveland National Forest. Large portions of the lower watershed fall into the Camp Joseph Pendleton Marine Corps Base. However, in the 1970s, the California Department of Parks and Recreation entered a lease agreement with Camp Pendleton (USFS, 1999b). At present, the beach area, marsh and lagoon, as well as the land along the creek inland and up Cristianitos Creek to the Orange County boundary, are parts of the San Onofre State Park. Today over 90% of the SMC watershed is public land with the remaining 10% being owned by private parties (USFS, 1999b). -Return to Top- History The landscape of the SMC watershed remained relatively undisturbed until the Spanish and European settlement of the region. With the arrival of a ranching culture, the landscape underwent significant changes. Native grasslands were slowly replaced by European and Asian weeds and other introduced plants. Some botanists argue that this invasion of exotic plants had more affect on the area than any other single factor (USFS, 1999a). [CS-ADD LINK TO WATERSHED MAP] Many historic factors have affected the condition of the SMC watershed. The following representative eras summarize the SMC watershed's history. Native Americans The early native American inhabitants of the coast and the Santa Ana Mountains included the Kumeyaay, Luisaños, Cahuella, and Capeño. These groups fished the streams and found an ample food supply among the abundant plant life. The explorers Vizcaíno and Cabrillo reported that the native Indians did considerable burning of the brushlands, but the overall impact was probably not very great (USFS, 1999a). Mission Period In 1769, the Spanish mission expeditions led by Junipero Serra and Gaspar de Portolá established settlements from San Diego to Monterey. European settlement of the SMC watershed was centered around the Mission San Juan Capistrano. Portolá camped at an Indian village north of San Onofre on July 22, 1769 on his way north to Monterey Bay. This 133,441-acre area was part of Rancho Santa Margarita y Las Flores, which was granted to Pio and Andres Pico in 1841.The Mission Period, which began in 1769, initiated the changes to the river system through the introduction of irrigation systems. The Spanish brought knowledge of aqueducts, and they built a huge system of them throughout California. Water was supplied from surface water bodies irrigating extensive gardens, orchards, and vineyards. The missions prospered until the separation of Mexico from Spain in 1821. The Secularization Act of 1833 ended the Mission Period and virtually eliminated the mission-owned lands. This resulted in the opening of large portions of land to settlement by private ranchers and the beginning of the Rancho Period. Rancho Period During this period, the land within the watershed was parceled out in the form of large Mexican land grants. These "ranchos" brought large numbers of cattle and sheep, which grazed upon the grasslands of the lower San Mateo Creek drainage basin. With the arrival of the Spanish, ranching became the predominant activity in the watershed. Large numbers of cattle and sheep grazed upon the grasslands of the lower San Mateo Creek drainage basin, drastically altering the native landscape. Widespread overgrazing throughout the area destroyed native vegetation. Rancheros cut brush and trees for fence posts and cleared underbrush with fires for foraging. Also, the introduction of plants from Europe and Asia displaced native grasslands, which probably created the single most destructive assault on the landscape. Ranching continued with European settlement and became the main land use activity in the area until the early 20th century. The San Mateo coastal plain and foothills provided not only ample grazing territory, but also the creek itself served as the major water supply for livestock in the region. At least three historic windmill wells pumped water from the creek bed, the remnants of which are still present. Pioneer Settlers In the late 1860's, an influx of gold miners from northern California descended upon the canyons of the Santa Ana Mountains within the upper SMC watershed. In addition to gold, other metals such as zinc, lead, and silver were mined and consequently altered the landscape. Trees were cut for mine timbers and firewood, and great expanses of brush were burned to make way for mineral exploration. Early reports from the 1870s and 1880s document uncontrolled fires that burned for weeks at a time. These events caused serious damage to irrigation works and threatened the water supplies of the surrounding rural areas and coastal towns. In response, the California Forestry Commission, established by Governor Stone in 1886, voiced the necessity for special protection of the watershed to prevent fires and subsequent erosion, which were "injuring the climate, agriculture and future prospects of southern California." Contemporary Period The Forest Reserve Act was signed by President Benjamin Harrison in 1891 to curb illegal timber cutting, mining and other wasteful practices. This Act established the boundaries of the Cleveland National Forest, which included a majority of the SMC's upper watershed. The Cleveland National Forest originally encompassed over 1.9 million acres. However, between the years of 1908 to 1925, several transfers of forest lands to private and public entities significantly reduced the size of the forest (USFS, 1999a). Today the Cleveland National Forest consists of approximately 420,000 acres. Early modifications to the San Mateo Creek included construction of the railroad embankment and trestle by the Santa Fe Railway, which stabilized the mouth of the creek (Fledmeth, 1987). In the 1930s, during construction of the old State Highway 1, a straight channel and associated leeves were constructed between the bridge and railway trestle. Upstream, several earthen reservoirs were constructed by farmers adjacent to the creek to increase percolation of runoff into the water table (Feldmeth, 1987). Levees were also constructed north of the current location of the I-5 freeway and on the western edge of agricultural fields. These leeves were constructed to prevent the San Mateo Creek from meandering and destroying cultivated areas on the river terrace. In 1950, the U.S. Marine Corps built Camp San Mateo to house recruits on the stream terrace just north of the confluence of Cristianitos Creek and San Mateo Creek. Sand and gravel were removed from the creek bed to supply construction material for the base.

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