PUB00109

• Year: 1995
• Title: Califormia Water
• CWCB Section: Interstate & Federal
• Author: Arthur L. Littlewort
• Description: History, overview, and explanation of water rights and legislation of California
• Publications - Doc Type: Historical

reliable supply cannot be based on removing stored groundwater
that will not be replenished.
An average of 15 million acre-feet of groundwater is pumped
each year in California, which meets about 20 percent of the state's
water requirements for municipal, industrial and agricultural uses.
This water is "recharged" (put back into groundwater storage) from
three sources. Natural recharge through rainfall, snowmelt and
stream seepage recharges 7.0 million acre-feet of water annually.
Water that seeps back into the ground after municipal, industrial, and
agricultural usage adds another 6.65 million acre-feet of recharge.
Also, additional water is added annually as part of groundwater
recharge programs. Despite this recharge, each year Californians use
about 1.3 million acre-feet of groundwater that is not replenished.
This excess withdrawal is referred to as "overdraft," defined gener-
ally as the deficit between the water pumped from a groundwater
basin and the long-term recharge.3
Overdraft has played a crucial role in the development of
California's water supply and the state economy. Declining local
groundwater tables forced the City of Los Angeles to look to the
Owens Valley and the Colorado River for additional supplies. Falling
groundwater tables were also a primary factor in the development
of the Central Valley Project.

California's Water Use
The history of developed water use in California began with the
Spanish missions in the late 1700s. Initially, most irrigation water
came directly from streams or small ditches that diverted streams.
There were no storage facilities, and, since summertime flows were
very low, the amount of acreage that could be irrigated was extremely
small. However, the need for storage began to be remedied with the
construction of dams in the late 1800s.
In the northern and central parts of California, water was
diverted from streams or artesian flows, while in the Sierra Nevada
mountains, water was taken from mining ditches. Irrigation was
driven by the population expansion that accompanied and followed
the gold rush. Most early irrigation was done by individuals, but as
early as 1856 a "commercial" company constructed canals to irri-
gate wheat in Yolo County. At the same time, groups of irrigators
began to join together to bnild ditches up and down the state.4

3 California Water Plan Update, volume 1, pages 5-6, 80-82.
4 ""Vater Utilization and Requirements of California," volume I, State of
California Bulletin, No.2, June 1955, page 22.

California has major groundwater :,'Upplies
which meet about 20 percent of the state's
water requiremen ts.

However, the state"s groundwater supplies
are being overdrafted by about 1.3 million
acre-feet a year.

Chapter 1 A Brief History 3