[Water_news] 1. DWR'S CALIFORNIA WATER NEWS - Top Items for 12/4/07

Department of Water Resources

California Water News

A daily compilation for DWR personnel of significant news articles and comment

 

December 4, 2007

 

1.  Top Items

 

Levees To Be Surveyed Underwater; Engineers Looking For Problem Spots - KCRA Channel 3 (Sacramento)

 

Sonar Survey of Levees Begins - KTXL Channel 40 (Sacramento)

 

New effort to repair Sacramento levees - KGO Channel 7 (San Francisco)

 

 

Levees To Be Surveyed Underwater; Engineers Looking For Problem Spots

KCRA Channel 3 (Sacramento) – 12/3/07

 

SACRAMENTO, Calif. -- The Department of Water Resources will conduct underwater surveys for more than 350 miles of levees in the region for weaknesses below the water line.

 

The Department of Water Resources is using an idea they borrowed from the U.S. Army Corps of Engineers by using sonar attached to the bottom of a boat to create an underwater map of the rivers and levees.

 

The department is looking for erosion or penetration in the levees in the urban areas of the Sacramento region.

 

The underwater map will give them a clear idea of problem spots -- information the department feels is essential in improving our flood protection and it will help determine the best way of fixing those areas.

 

The engineers behind this survey said the sonar mapping will get the quickest, most detailed results.

 

Claudio Avila said the department is surveying the Sacramento River, San Joaquin River and part of the American River in less than three weeks, and that a typical survey crew would take much longer. #

http://www.my58.com/news/14762465/detail.html

 

 

Sonar Survey of Levees Begins

KTXL Channel 40 (Sacramento) – 12/3/07

 

WEST SACRAMENTO — This year, Sacramento and West Sacramento voters approved property tax increases for flood protection.

But before that money is spent, the state wants to find out which levees are most in need of repair.

For three weeks, private surveyors from a Netherlands-based company will be using a multi-beam sonar to provide detailed topographic images of the Sacramento, American, San Joaquin and Calaveras Rivers.

It's called a bathymetric survey. Images show color-coded depths, and engineers can then determine where the worst erosion has taken place.

The acoustic signals that are bouncing off the riverbed basically are translated into data. The results are then broadcast in real time on a monitor.

Engineers expect to see plenty of structural decay along the hundred miles of riverbed being mapped.

"When you look at the levee system overall in California, most of it was built by farmers back in the 1800's. So we have levees that were never engineered in a lot of our areas," said Scott Woodland of the Dept. of Water Resources.

Before Hurricane Katrina, the California Department of Water Resources had published a white paper, laying out for the governor just how weak the urban levees were.

"They had just really started to look at it when Katrina happened and that really pushed everything to the forefront and we really made a push to make all this happen," said Woodland.

The data is supposed to be ready to act on by August. #

http://fox40.trb.com/news/ktxl-120307levee,0,5397588.story?coll=ktxl-news-1

 

 

New effort to repair Sacramento levees

KGO Channel 7 (San Francisco) – 12/3/07

 

SACRAMENTO, Calif., Dec. 3, 2007 (KGO) -- There's a new effort underway to shore up the sagging levees in the Sacramento Delta, and thereby protect the water supply for millions of people in the San Francisco Bay Area.

 

The State Department of Water Resources is sending boats with advanced sonar imaging devices on board into the Sacramento River to find out how badly the levees have eroded. At stake, is water for the Santa Clara Valley and major parts of the East Bay, and what some call, a Katrina like event in the Sacramento Delta.

 

The State Department of Water Resources sent out a small boat to investigate a big problem - that of levee erosion along hundreds of miles of the Sacramento, American, San Joaquin and Calaveras Rivers.

 

"If they are stable and if they have possible problems that we can identify - then we can fix or remediate," said Claudio Avila, State Engineering Geologist.

 

That is the sonar device which using soundwaves produces an image, which is interpreted by Gilberto Suarez a surveyor for Fugro Offshore Survey.

 

"There's some erosion going on in some areas, it varies," said Gilberto Suarez, Fugro Offshore Surveyor.

 

The darker the green, the more erosion.

 

"Especially when it goes around the bends, it tends to create erosion on one side and sedimentation on the other - so there's some real nice features down there, it's not as flat as some people think," said Suarez.

 

Officials have already surveyed the levees from above. With sonar imagery they can see how much of the levee has been eroded below the water line. It puts them in a better position to figure out what and how to repair.

 

Last week, a task force put together by Governor Schwarzenegger urged an immediate effort to guard against flooding here. It's hoped the levees, which have lasted which have lasted a century, can hold on until that fix can begin.

 

New information from the sonar devices is going to be included with all the other information that they have. It is going to be included in a report due out next fall which will include ways to repair the levees. #

http://abclocal.go.com/kgo/story?section=news/local&id=5810914

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