San Luis Rey
San Diego County Department of Parks and Recreation http://ceres.ca.gov/wetlands/geo_info/so_cal/san_luis_index.html
The San Luis Rey River Estuary is located in the City of Oceanside. The
watershed extends into unincorporated San Diego County. The vast majority
of the 164-acre floodplain is privately owned. The Oceanside Harbor and
the lower river channel are owned by the City of Oceanside.
San Luis Rey River is an ephemeral river which stays dry most of the
time. In 1977, the peak discharge at the mouth was estimated for a 100-year
flood to be 51,000 cubic feet per second. The river is confined by a 400-foot
wide earthen channel bounded by two levees along the lower seven miles.
Mineral and aggregate mining has occurred at several sites in the river
channel. The Henshaw Dam, built in 1922, controls 36% of the watershed.
Wetlands in the floodplain were once used for agriculture. The City of
Oceanside discharged treated wastewater into the river from 1958 to 1974.
The estuary at the mouth of the river was dredged in 1964 to create the
Today, the Oceanside General Plan Land Use Element designates the majority
of the San Luis Rey River floodway as General Open Space or Agricultural.
The lower part of the river is within a designated Resource Conservation
Area overlay in the County General Plan.
The wetland is used by eight sensitive bird species. Other special
status species include black-shouldered kite, white-faced ibis, western
snowy plover, Beldings savannah sparrow, and least Bells vireo.
The estuary, which once sprawled more than 2,200 acres, has been altered
by agriculture and urban development within the floodplain and watershed;
and mineral and aggregate extraction in the channel. A Habitat Conservation
Plan has been developed for the rivers least Bells vireo population
and is currently being implemented. The plan designates 12 acres of riparian
habitat west of I-5 as Conserved Habitat.