Hazards to California's Delta Water System

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Detailed Description

This short video is one of a series of four total shorts highlighting USGS water science in California's Delta region. Earthquakes, land subsidence and flooding pose significant threats to California’s fresh water. Aqueducts, pipes and sewer lines can break and levees can breach. In the Sacramento-San Joaquin Delta at the heart of the state’s freshwater system, the huge areas of farmland between leveed channels could suddenly be under water and water to more than twenty five million people could be crippled or cut off entirely. These are complex problems in need of attention and solutions. USGS Scientists are conducting a variety of diverse research to mitigate hazards in the Delta region. 
 

Details

Image Dimensions: 1280 x 720

Date Taken:

Length: 00:02:57

Location Taken: Sacramento, CA, US

Transcript

Narrator: 
Earthquakes, land subsidence and flooding pose significant threats to California's fresh water.

Aqueducts, pipes and sewer lines can break and levees can breach. 

In the Sacramento-San Joaquin Delta at the heart of the state's freshwater system, the huge areas of farmland between leveed channels could suddenly be under water and water to more than twenty five million people could be crippled or cut off entirely.

Impacts would affect everything from families to farmers to fish, and be felt well beyond California.  

Delta farms are subsiding because they sit atop ancient marshlands, which break down over time.  As the land subsides, the levees are weakened. 

Over a thousand miles of levees in the Delta are at risk of failure.

Compounding the problem a few earthquake faults pass through the Delta, while much larger faults run just beyond that. 

In wet years, flooding from severe winter storms can over-top 
levees or cause weakened levees to breach.  

If the levees failed, salt water from the Bay could be rapidly drawn into the Delta and potentially reach the water system pumps.  

This could contaminate much of the state's fresh water supply and destroy livelihoods and local commerce where Delta farms would be flooded with saltwater. 

These are complex problems in need of attention and solutions. 

USGS Scientists are working to better understand the vulnerability ... 
of the Delta's levees to various hazards. 

They're monitoring ground motion from all nearby faults and they're building three-dimensional models  of the geologic subsurface to better predict how strong ground motion will spread following a major earthquake.  

They're defining historic flood patterns to help managers identify which levees to reinforce or where to stage materials for possible breaches.

Teams of USGS scientists monitor hydrologic flows and coordinate with water operators who would workto keep salt water out of the pumps after an earthquake levee break, or other event. 

This is critical information that local governments and emergency response teams can use for planning making us better prepared to respond to catastrophic levee failure.

Want to know more about hazards facing the Delta's water system? 

Why not start with science.