From the Guidebook:
This is the terminus of the
Los Angeles-Owens River Aqueduct, which brings water 338
miles from the eastern slopes of the Sierra Nevada to
the City of Los Angeles. Begun in 1905, the great aqueduct
was completed November 5, 1913. The Mono Craters Tunnel
project, completed in 1940, extended the system 27 miles
to its present northernmost intake near Tioga Pass.