Santa Margarita River

The Santa Margarita River which with the addition of what is now Temecula Creek, was formerly known as the Temecula River, is a short intermittent river on the Pacific coast of Southern California in the United States, approximately Template:Convert<ref name=NHD>U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. The National Map, accessed March 16, 2011</ref> long. One of the last free-flowing rivers in Southern California, it drains an arid region at the southern end of the Santa Ana Mountains, in the Peninsular Ranges between Los Angeles and San Diego.

History

The Portolà expedition camped on the river on July 20, 1769 and named it for Saint Margaret of Antioch. A Santa Margarita rancheria is mentioned in 1795 and there is a February 23, 1836 land grant called Santa Margarita y San Onofre (later renamed Rancho Santa Margarita y Las Flores).<ref name=Gudde>Template:Cite book</ref>

In 1881 the California Southern Railroad followed the route of the river.<ref name=PE2011>Template:Cite web
Template:Cite news</ref> When the route was completed, it had 241 bridges crossing the river.<ref name=PE2014>Template:Cite news</ref> While it was operating, Chinese Americans worked on the railroad.<ref>Template:Cite journal</ref> The route along the river was abandoned in 1891.<ref>Template:Cite news</ref>

In the early 20th century, following a lawsuit against Vail Ranch in Temecula, water was guaranteed for the river to continue to flow.<ref>Template:Cite report</ref> During much of the 20th century, and into the early 21st century, the river was the subject of a long-running water rights battle between the United States Navy and the Fallbrook Public Utility District.<ref>Template:Cite news</ref> In August 2018, the Fallbrook Public Utility District sold its land on the river, ending its over 60-year plan to place a hydroelectric dam on the river; it will be preserved by the Wildlands Conservancy as the Santa Margarita River Trail Preserve, which utilized funds from bonds authorized by Proposition 68 to purchase the land.<ref>Template:Cite news</ref>

Watershed and course

Temecula Canyon

The mainstem of the Santa Margarita River begins at the confluence of Temecula Creek<ref name=TemeculaCreek/> and Murrieta Creek,<ref>Template:Cite gnis</ref> in southwestern Riverside County, east of Interstate 15, Template:Convert southeast of Temecula.<ref name=TemeculaCreek>Template:Cite gnis</ref> The river is formed when the two creeks merge.<ref name=PE2014 /> It flows southwest through the Template:Convert Temecula Canyon at the south end of the Santa Ana Mountains. Along its lower Template:Convert the river forms a large floodplain as it crosses Camp Pendleton Marine Corps Base. It enters the Gulf of Santa Catalina on the Pacific approximately Template:Convert northwest of Oceanside.

Draining Template:Convert, the Santa Margarita Watershed is the second largest river basin on the Southern California coastal plain.<ref name=Stein>Template:Cite journalTemplate:Dead link</ref> The upper watershed consists of the Template:Convert Murrieta Creek subwatershed and the Template:Convert Temecula Creek subwatershed. Although there are two dams in the upper watershed, both dams must release water that roughly corresponds to natural flows in the tributaries that they are on. As a result, the flow of water in the Santa Margarita River is very close to what it would be in the absence of those two dams.<ref name=Reserve>Template:Cite web</ref>

Below the confluence of Murrieta and Temecula Creeks, the primary tributaries of the Santa Margarita River mainstem are Rainbow Creek on the left (headingdownstream) and Sandia Creek and De Luz Creeks on the right. The two latter creeks drain the Santa Rosa Plateau.<ref>Template:Cite book</ref>

Conservation and ecology

Approximately Template:Convert of the middle course of the Santa Margarita River in Temecula Canyon are managed by San Diego State University as the Santa Margarita Ecological Reserve, a collaboration of the Bureau of Land Management, California Department of Fish and Wildlife and The Nature Conservancy. The Nature Conservancy has identified and continues to acquire land along the river for conservation. Downstream from the Ecological Preserve the river flows through The Wildlands Conservancy Santa Margarita River Trail Preserve, and empties into the Ocean through the largely undisturbed lands of Camp Pendleton. Thus the mainstem flows through undeveloped, protected lands. The river has unusual habitats with the upper mainstem one of the few remaining natural gorge rivers in Southern California and the lower mainstem has expansive riparian strips, some up to Template:Convert across.<ref name=Stein/>

Approximately 70 species of special concern (rare, threatened, or endangered) regularly inhabit the watershed, including 30 that are currently protected under the Endangered Species Act.<ref name=Stein/> Two federally endangered riparian birds are the least Bell's vireo (Vireo bellii pusillus) and the southwestern willow flycatcher (Emmpidonax traillii extimus)), both of which require riparian habitat for breeding success.

Major fishes in the Santa Margarita River include the rainbow trout (Oncorhynchus mykiss), arroyo chub (Gila orcuttii), California killifish (Fundulus parvipinnis), striped mullet, longjaw mudsucker, staghorn sculpin. Pacific lamprey (Entosphenus tridentatus) recolonized the river in August 2019 for the first time since 1940, the furthest south the species has currently recolonized, Template:Convert south of the previous location in San Luis Obispo which recolonized in 2017. The successful recolonization has been attributed to a rebuilt weir and new fishway at Camp Pendleton which allowed the lamprey to find passage into the river.<ref>Template:Cite news</ref> Aquatic and semi-aquatic mammals include California golden beaver (Castor canadensis subauratus), muskrat, raccoon and long-tailed weasel.<ref name=Rivers>Template:Cite book</ref> Contemporary beaver populations survive at the headwaters of the Santa Margarita River at the confluence of Temecula Creek and Murrieta Creek.<ref>Template:Cite web</ref>

Major riparian plants include arroyo, black, narrowleaf, Pacific, and red willow (Salix spp); California sycamore (Platanus racemosa), Fremont cottonwood (Populus fremontii), mulefat (Baccharis salicifolia) and White alder (Alnus rhombifolia).<ref name=Rivers/>

External links

• The Santa Margarita River - Fallbrook Area Information by Tom Chester
• SDSU: Santa Margarita Ecological Preserve
• California Rivers - Friends of the Santa Margarita River