Water Erosion in California
(Steven Dutch, Natural and Applied Sciences, University of Wisconsin - Green Bay )

The Imperial Valley of California is below sea level because it is a former part of the Gulf of California cut off
by the Colorado River delta. The valley has a year-round growing season and is one of the most important
agricultural areas in the U.S. At one time it was almost entirely dry, but about 1910 an irrigation canal from the
Colorado River overflowed and flooded a large part of the center of the valley. By the time the flood was
stopped, residents decided that a lake might not be a bad idea, so it is still there. It's called the Salton Sea and
is maintained artificially.

Clear Lake is the largest and most misnamed natural lake entirely within California (Lake Tahoe is shared
with Nevada). To the west is a steep and short drop to the Russian River, but the former valley there was
dammed about a million years ago by lava flows. The valley flooded and found an outlet to the east, where
more volcanic rocks slow deepening and erosion of the outlet.