Residents helped reshape Valley's landscape
![]() A hydraulic mining operation near French Corral is seen in this 1860s photo Credit: Courtesy of The Society of Calif |
SAN ANDREAS - Humans have radically reshaped the
Central Valley and the neighboring Sierra Nevada foothills in the past 157
years.
Gold Rush miners armed with water cannons washed away entire hills. Silt from
that mining flowed down to the Valley where it plugged rivers, filled in parts
of San Francisco Bay, and by 1884 triggered the state's first environmental
court decision.
In the mountains, miners chopped down entire forests to fuel heating fires,
build towns, and timber the shafts of hard-rock mines.
In the Valley, farmers converted oak woodlands and marshes into the world's most
productive food basket. State and federal engineers raised mighty dams, changing
the course of rivers to slake the thirst of those farms and of huge cities
arising on the coast and in southern deserts.
After World War II, population from the coastal cities sprawled inland. The
automobile made it possible for hundreds of thousands of newcomers to settle in
Valley suburbs and in ranchettes scattered in the hills.
This remaking of the land yielded tremendous wealth from gold, grain, grapes,
timber, real estate and hundreds of other products. It also killed some rivers,
choked others, decimated or destroyed salmon runs, and doomed millions of people
to live in a place with tainted air and water.
Some of the pollution dates back to the Gold Rush. Toxic mercury from then is
still concentrating in Delta fish caught and consumed by some Valley residents.
Air pollution is more recent, largely but not entirely tracing to the massive
use of motorized vehicles in the past 60 years in a place where mountains
sometimes trap stagnant air.
Perhaps the strangest corner of the region is the Sacramento-San Joaquin River
Delta, where ocean-going ships tower over rows of corn and tomatoes growing on
below-sea-level islands.
"It is completely transformed," said John Thompson, a retired
professor of geography at the University of Illinois, Champaign, who earned his
doctorate at Stanford and wrote his dissertation on the geography of the Delta.
Until the Gold Rush, the Delta was a sea-level marsh. In some places, it had
deposits of peat soil up to 65 feet deep, Thompson said.
Scientists say the soils built up as plants died in the water and sea levels
gradually rose over the 6,000 years since the end of the last ice age.
The San Joaquin, the Sacramento and other smaller rivers carved channels through
the Delta. During spring floods, the rivers deposited banks of mud that served
as a sort of low natural levee for the peat soil marshes.
Farmers arriving after the Gold Rush discovered that they could make the levees
higher - first by hand then after 1878 by using powered dredges - thus creating
'islands' of rich peat soil.
Then they started farming
"Land preparation was done by fire, because the tules were pretty tough to
break by plow," Thompson said.
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Contact reporter Dana M. Nichols at (209) 754-9534 or dnichols@recordnet.com