The Central Valley is a vital agricultural region that dominates
the center of California, stretching 40-60 miles east to west and
about 450 miles from north to south. It covers 22,500
square miles, about 13.7% of California’s total land area.
The Mexican Water Treaty of 1944 committed the U.S. to deliver
1.5 million acre-feet of water to Mexico on an annual basis, plus
an additional 200,000 acre-feet under surplus conditions. The
treaty is overseen by the International Boundary and Water
As adjacent Western states, California and Nevada share similar
issues related to drought and limited water resources. Both
states are participants in the 1922 Colorado River Compact and
the 2003 and 2007 Quantification Settlement Agreements to
allocate Colorado River deliveries. Also, about two-thirds of
Lake Tahoe lies in California and one-third in Nevada, and the
two states have formed a compact to work together on
environmental goals for the lake.
Pyramid Lake in Nevada has long been a focal point in a
tug-of-war between water stakeholders. There’s been a struggle
for water in this arid land among the American Indians, farmers,
cities, environmentalists and the people of Nevada and
California. The lake is the site of the nation’s first
reclamation project and the subsequent struggles among Nevada
farmers, the Paiute Indian Tribe and the growing city of Reno
over use of the lake’s water. In 1990 a settlement act attempted
to resolve some of these competing uses.
The Sacramento Valley, the northern part of the Central Valley,
spreads through 10 counties north of the Sacramento–San Joaquin
River Delta (Delta). Sacramento is an important agricultural
region, growing citrus, nuts and rice among many other crops.
The San Joaquin Valley stretches from across mid-California
between coastal ranges in west and the Sierras on the east. The
region includes large cities such as Fresno and Bakersfield,
national parks such as Yosemite and Kings and fertile farmland
and multi-billion dollar agriculture industry.
Until the early 1900s, central California’s Tulare Lake naturally
appeared every winter as the southernmost rivers flowing out of
the Sierra Nevada Mountains filled the dry lakebed with rainfall
and melted snow.
Farmers adjacent to the lake also used the water to irrigate
their lands. But the variable shoreline made growing seasons
unpredictable. In response, Pine Flat Dam was built by the U.S.
Army Corps of Engineers to control Kings River flows. The Kings
River is still used extensively for irrigation.