Satellites Monitor California’s Sinking Central Valley

The Political Hacks are Clueless

• The drought threatens the entire economy of California. But the moronic bipartisan political hacks in Sacramento still have done nothing about building a string of desalination plants up and down the coast.
• Meanwhile. countless billions (billions with a "B") are pissed down a corrupt rat hole to build a "bullet" train to nowhere. 

(Wired Magazine)  -  CALIFORNIA IS RUNNING on groundwater right now. As the state has cut down on surface water deliveries from rivers and reservoirs, farmers and municipal water suppliers have reacted by sucking more and more out of Madre Earth. The state’s land, in response, is sinking lower and lower, day by day, year by year.

In times of crisis, turning to groundwater is understandable (it may even be unavoidable). But—as it stares down its inevitably dessicated future—California is finally waking up to the need to monitor and protect these reserves. To do that, the state’s Department of Water Resources is turning to new techniques using satellite data which, by measuring changes in the ground above, can keep an eye on water levels below. Essentially, if the Golden State is going to weather this disaster, it will need some help from up high.

Earlier this week Tom Farr, a geologist at NASA’s Jet Propulsion Laboratory in Southern California, completed the first of many maps for the California Department of Water Resources with data collected by the European Sentinel-1 satellite. That map, of the state’s agriculture hub in the Central Valley, is part of a larger project to use NASA expertise to study—and try to help combat—California’s drought.

Subsidence in California's Central Valley

This animation shows, in exaggerated terms, how the surface of the southern Central Valley of California deformed from the period 2007 to 2011. Interferometric data from the Japanese ALOS PALSAR imaging radar was used to measure the deformation, shown in color overlaid on an ASTER image. The large subsidence "bowl" that developed over this time period was caused by withdrawal of groundwater, causing subsurface layers to compact. Interferometric synthetic aperture radar, or InSAR, can be used to monitor subsidence in order to prevent groundwater overdraft and irreversible compaction of aquifers. ALOS PALSAR data is copyright JAXA/METI and was provided by the GEO Supersites and the U.S. Government Research Consortium datapool at the Alaska Satellite Facility.

One of the ways California will use Farr’s maps is to identify groundwater trouble spots (the faster the land is sinking, the faster the water is being depleted). A new law signed last year by Governor Brown requires regional water agencies to devise groundwater sustainability plans. To do that, though, they’ll need good data. And, at the moment, good groundwater information is hard to find and expensive to gather.

The state can monitor groundwater directly by measuring water levels within wells—but digging new wells is expensive, and existing wells may be on private land. “The other problem,” Farr says, “is that you’re not sure what kind of aquifer they’re drilled into.” Aquifers can be confined, separated from the surface by an impermeable layer of dirt or rock, or unconfined, with water entering from the ground directly above. 

Well data can be hard to interpret as most wells penetrate more than one level in the aquifer system. So, not only is the water-level in the well hard to interpret in terms of groundwater volume, explains Farr, but they provide portals for water to move between different parts of the aquifer system—altering the very thing geologists seek to measure.

Read More . . . .

Overpumping Water in a Desert

In 1892 (above) Tulare Lake was once the biggest 

freshwater lake west of the Mississippi.​

What remains of Tulare Lake today after endless
overpumping of ground water in order to grow crops,
build cities and golf courses in a desert.

That sinking feeling
The sign reads, " San Joaquin Valley California Subsidence, 3M 1925 - 1977."  The Central Valley has been sinking from over pumping for a century.
(Water California.org)