The Mono Basin Project
As the country emerged from the Great Depression and entered
World War II, Los Angeles voters continued to approve financing for
The Mono Basin Project was a construction program to obtain
a larger and more dependable flow of water to the Los Angeles Aqueduct.
The DWP planned to extend the Los Angeles Aqueduct 105 miles
further north, 338 miles from Los Angeles, to take water diverted from
the four creeks it had applied for permits for in 1923.
By taking water from Parker, Walker, Lee Vining and Rush creeks,
the City would obtain a high quality water supply for 500,000 people.
In 1935 the City applied to the Division of Water Resources
to construct Grant Lake Dam to store water from the creeks.
The application was referred to the State Fish and Game
Commission for a determination of whether a fishway would be required
for the dam. The Fish and
Game Commission determined that no fishway would be
required and construction of the dam was approved by the Department of
The City had also finally acquired the reservoir site at
Long Valley. In the DWP’s
1936 application to build a dam there, the same fishway issue was
examined and this time a Fish and Game Commission hearing determined
that an alternative method of providing fish culture would be provided
to compensate for fish losses caused by the construction of both dams.
Following several investigations and studies, the City and
the Fish and Game Commission executed the Hot Creek Agreement in 1940.
Under the agreement the City was to provide land, water rights,
access roads, and construction funds for the construction of the Hot
Creek Fish Hatchery, now probably the most productive fish hatchery in
An 11 mile tunnel was drilled through the volcanic Mono
Craters to obtain water from Lee Vining, Parker, Walker, and Rush
creeks. It increased the
capacity of the aqueduct system 35% to about 300 million gallons per
day. The Long Valley Dam created
Crowley Lake Reservoir, the largest reservoir in the Los Angeles water
By the time the United States entered World War II, the
Mono Basin Project was complete. Los
Angeles swiftly became one of the country’s most important war
production centers. Its
heavy manufacturing base continued to diversify, and the population grew
with the war effort.
When the war ended, the stage was set for an economic boom
with Los Angeles as prime beneficiary.
By 1950, Los Angeles had a population of two million people and
had become the fourth largest city in the United States. The DWP built the Owens River Gorge Hydroelectric Generating
Station, the Valley Generating Station, and the Scattergood Generating
Station to meet the growing demand for power.
The development of a series of hydroelectric power projects
was a natural result of the engineering design of the Los Angeles
Aqueduct. The aqueduct had
been designed to deliver water to Los Angeles entirely by gravity,
requiring no power for the pumping of water along the route. Using this natural gravity flow, engineers designed a series
of penstocks that dripped the water to power plants located at the
bottom of the Gorge. The
force of the water was used to move turbines and create electricity.
During the 1960s there were certain years where the
population of California grew as much as 1,500 persons a day.
By the end of the decade one in ten persons in the U.S. lived in
California. Los Angeles was
the premier city in the country’s most populous state.