What is a river basin?

A river basin consists of a portion of land where atmospheric precipitation (rain or snow) runs off into a single river through its various tributaries, to eventually discharge into the sea or some other body of water. Depending on the characteristics of the basin, part of the precipitation infiltrates into the subsoil, recharging the aquifer.

The Tijuana River basin

The Tijuana River basin covers 4,465 km2 (1,750 mi2 ), from its headwaters in the Laguna Mountains in California to the northeast and the Sierra Juarez Mountains in Baja California to the south, to its mouth at the Tijuana River Estuary in Imperial Beach, San Diego County, California, and to the urban areas of Tijuana and Tecate.

In the United States portion, 93% of the basin falls under the jurisdiction of San Diego County. In Mexico, almost all of the TRB is under the jurisdiction of the municipalities of Tijuana and Tecate and a small part corresponds to the municipality of Ensenada.

In our region, the Tijuana River Basin (TRB) corresponds to the portions of California and Baja California where precipitation flows to the Pacific Ocean via the Tijuana River and its tributaries, including the Tecate, Alamar, Las Palmas and El Florido rivers.

Communities in the U.S. portion of the Tijuana River Basin include the incorporated cities of Imperial Beach and San Diego (including the communities of San Ysidro and Otay Mesa), Campo, Barrett Junction, Potrero, Pine Valley, Morena Village, Buckman Springs, Boulder Oaks, Tierra del Sol, and Tecate (U.S.). The Kumeyaay Indian reservation includes Campo, Manzanita, and part of the La Posta and Cuyapaipe territories.