California Levee Failures: 6000 BC to 2000 AD.

History, starting at 6000 BC: In those days the streams were fast running and braided, with long straight gravelly stretches, much like the streams in mountain valleys today. The gravels were highly pervious, that is good carriers of water, and are still tapped as sources of water for farm and domestic wells.

Then at about 3000 BC a combination of global events, including sudden climatic change, floods, and possibly meteor impact, shocked the rivers into a new type of flow.

Major rivers throughout the world began to meander, swinging back and forth in their channels.

The next major trauma to affect the Yuba and other Sierra streams was the hydraulic gold mining in the 1860s. Giant hoses washed away mountainsides, choking the river channels with golden silt.

In the late 19th century levees were built to confine the rivers to the center of their old channels. The lust for land replaced the greed for gold. The levee builders ignored the old river channels, hoping to confine the river. The old channels remained buried beneath the golden silt and the black fertile orchard lands.

Today, knowledge of the old ways of the river is the key to predicting the fatal flaws in our attempts to control nature. The meanders of the rivers are the failure hot spots.

Lance Williams' San Francisco Examiner article
Air photos of the Marysville area, before and after flooding
USGS topographic and levee failure map
Land developments
Geological history of levee weak spots
Similar problems near Pajaro
How the bible provides an early prediction of levee failures
Mechanics of levee failures
Sinkholes and sand boils
Shanghai Bend: past and future
Preventing levee failures
Author

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