Geoscience Reference
In-Depth Information
including the burgeoning San Joaquin Valley agricultural lands and growing
cities in Southern California. A massive water conveyance canal, called the
California Aqueduct, was completed during a relatively wet period in the
state that followed the Dust Bowl drought, in the 1940s and 1950s.
the drought of 1987-1992
h e Dust Bowl drought was one of only two droughts that have lasted more
than four consecutive years in California since 1850, when the state began
keeping records. A later drought of similar magnitude and duration began in
1987, and it makes for an interesting comparison. California's population had
expanded from seven million in the 1930s to thirty-one million in the 1980s,
and agriculture had grown to an industry worth $30 billion a year, heavily
dependent on the extensive water infrastructure that had been built during
the intervening years.
During the multiyear drought that began in 1987, annual precipitation
over much of California was down to only 50 percent of the twentieth-
century average. h is drought af ected the entire state, and, though no single
year was as severe as the 1976-77 drought described in chapter 1, the cumula-
tive ef ects were ultimately more devastating.
h e 1987-92 drought crept up on the state. Reservoirs had enough water
stored to buf er the i rst three to four years, but, at er the fourth year, reser-
voir storage statewide was down 60 percent. Severe restrictions, with reduc-
tions of 75 percent, were imposed on water delivery for agricultural uses, and
reduced river l ows caused a decline in hydroelectric power generation.
In Southern California, the two reservoirs for the city of Santa Barbara
dried up almost entirely, forcing the city to build a pipe connecting to the
California Aqueduct through the Santa Ynez Mountains at a cost of hun-
dreds of millions of dollars. Many more millions were spent by the city on
one of the world's largest seawater desalination plants, built as an insurance
policy for the vulnerable city.
h e impacts on the environment were also mounting. Bark beetle infes-
tations caused widespread mortality in the forests of the Sierra Nevada,
where extensive stands of pine trees, already weakened from the drought,
succumbed to disease. Reduced stream l ow led to major declines in i sh
populations, including the chinook salmon and striped bass, decimating
commercial and recreational i sheries.
