[Ccpg] Fwd: [ENVIRO-NEWS] Central Valley Subsidence Study Launched

[yankeeperm at aol.com]

-----Original Message-----
From: Makuch, Joseph <Joseph.Makuch at ARS.USDA.GOV>
To: Enviro-News at NAL.USDA.GOV
Sent: Fri, Sep 4, 2009 4:21 pm
Subject: [ENVIRO-NEWS] Central Valley Subsidence Study Launched








From: owner-water-pr at igsrsparc2.er.usgs.gov
[mailto:owner-water-pr at igsrsparc2.er.usgs.gov] On Behalf Of WR Office of
Communications
Sent: Friday, September 04, 2009 2:43 PM
Subject: USGS Release: Central Valley subsidence study launched


This release can be found in the USGS Newsroom at:
http://www.usgs.gov/newsroom/article.asp?ID=2300.

News Release

    
September 4, 2009 

Jim Nickles 
916-278-3016 
jnickles at usgs.gov 



    

Central Valley subsidence study launched


USGS will track cause and extent of ground sinking near California
Aqueduct

The latest satellite tracking data will be used to help scientists gain
a better understanding of how land subsidence is affecting the
state-owned California Aqueduct in California's San Joaquin Valley.

Under a new agreement, the U.S. Geological Survey will conduct the study
on behalf of the California Department of Water Resources, which
operates the aqueduct that carries water from the Sacramento-San Joaquin
Delta to the San Joaquin Valley and Southern California.

The research will address growing concerns that increased groundwater
pumping in the San Joaquin Valley may be causing land surfaces to sink,
or subside, damaging the concrete channel.

Historically, extensive pumping of groundwater from the San Joaquin
Valley aquifer system caused groundwater levels to decline, resulting in
as much as 28 feet of land subsidence. The importation of surface water
to the San Joaquin Valley in the 1970s reduced demand for groundwater,
resulting in a recovery of groundwater levels and a reduced rate of land
subsidence.

Groundwater pumping in the Valley has increased in recent years as
drought and fish-protection measures have curtailed surface-water
deliveries.

The three-year, $255,000 project will help the state better manage
California's water resources and minimize the impact of land subsidence
on the facility. The state will provide $202,000 to fund the research,
while the federal government will provide $53,000.

USGS scientists will use a satellite-imaging system known as
Interferometric Synthetic Aperture Radar (InSAR) to create maps of
changes in land-surface elevation at selected locations over the last
several years.

The research will focus on the California Aqueduct along the west side
of the southern San Joaquin Valley, in the area of the Westlands Water
District. The research will seek to:

*   Use InSAR to determine the location, extent and magnitude of
changes in land-surface elevation along the aqueduct from 2003-2010.

*   Develop and implement an approach to use InSAR to provide
on-going tracking of subsidence.

*   Compare changes in land-surface elevation computed from InSAR
and from continuously operating Global Positioning System stations to
changes in measured groundwater levels.

"This is the first time we have used this type of InSAR imaging to track
subsidence in the Central Valley," said Michelle Sneed, the lead
scientist on the study. "If this works as well as we hope, we may be
able to develop a monitoring program to regularly track changes in
land-surface elevation and their relation to groundwater levels."

For more information, including list of frequently asked questions and
answers, visit the California Water Science Newsroom
<http://ca.water.usgs.gov/news/MoreInfoSept4_2009.html> .


USGS provides science for a changing world. For more information, visit
www.usgs.gov.
[deletions]
 



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