Thousands of years ago during the last Ice Age, rivers flowed from giant glaciers in the Sierra Nevada down to the Central Valley, carving into rock and gouging channels at a time when the sea level was about 400 feet lower. When the glaciers retreated, meltwater coursed down and buried the river channels in sediment.
When it comes to natural disasters, the sudden, swift devastation of landslides, mudslides, and sinkholes may get all the attention — but natural resource scientists can attest that it’s the slow sinking of the ground surface that is just as real a danger. “Subsidence often gets neglected because it is slow moving. You don’t recognize it until you start seeing damage,” says Michelle Sneed, a land subsidence specialist at the United States Geological Survey (USGS).
The Water News Network is San Diego County’s source for water news and information.
