The Tehachapis are delineated from the San Emigdio Mountains by Tejon Pass at the range's western end. The dramatic incline of Interstate 5 from the San Joaquin Valley floor up to the pass, is regionally referred to as The Grapevine, after Grapevine Canyon which it follows between the northern slopes of the two mountain ranges and is sometimes extended to include the portion of Interstate 5 on the southern side of Tejon Pass, especially during snow closures. The canyon was named after native grapevines, the California grapevine (Vitis californica), found at springs on its slopes. The California State Water Project is to the east, with the California Aqueduct pumped by the Edmonston Pumping Plant over/through the Tehachapis to Castaic Lake reservoir.