Planning the Tehachapi Crossing

Abstract

Planning the California Aqueduct crossing of the Tehachapi Mountains in California north of Los Angeles involved 10 yrs of intensive research and study in the United States and Europe to design a 4,100-cfs (116,112 l/s), 2,000-ft (610m) high-head pump lift, the largest in the United States. Engineering examination of alternate aqueduct routes over the high mountain ranges ended in selection of a crossing at El. 3100 (945.5m). Study of the number of pump lifts was resolved in favor of a single-lift on the Ridge Route. Model tests of various types of European and American pump designs identified as most suitable a vertical four-stage single-flow centrifugal pump 33 ft (10.065m) in height, 16 ft (4.88m) in diameters. Ten miles of 23.5-ft (7.18m) diam tunnel convey the pumped water through the mountain range. The Tehacapi Crossing has been in operation since October, 1971.