Some questions about land subsidence

Submitted: Aug 19, 2015
By: 
Badlands Journal editorial board

 Some questions from the center of the drought, where the towns are brown and orchards, vineyards and rowcrops are green:

 

How many people are really being economically injured by this drought?

How will Farm Bill crop insurance programs and other government subsidies and disaster payments go to ease the pain?

How much of the great contiguous aquifer that lies under the San Joaquin Valley has been destroyed by land subsidence?

Will local groundwater sustainability plans stop or even slow down subsidence?

Will the state stop or slow down subsidence?

Will the federal government stop or slow down subsidence?

 

How much rain does it take to fill up a collapsed aquifer?

 

We'll take our answers in one of the two usual form the authorities offer the public:

1. Silence.

2. Anwer another question.

 

 -- blj

 

8-19-15

California Department of Water Resources

NASA Report: Drought Causing Valley Land to Sink 

Contacts:

Ted Thomas, DWR Information Officer

(916) 653-9712

Ted.Thomas@water.ca.gov

Alan Buis, NASA Jet Propulsion Laboratory

(818) 354-0474

Alan.buis@jpl.nasa.gov

 http://www.water.ca.gov/news/newsreleases/2015/081915.pdf 

SACRAMENTO, CA — As Californians continue pumping groundwater in response to the historic drought, the Department of Water Resources today released a new NASA report showing land in the San Joaquin Valley is sinking faster than ever before, nearly two inches per month in some locations.

“Because of increased pumping, groundwater levels are reaching record lows—up to 100 feet lower than previous records,” said Department of Water Resources Director Mark Cowin. “As extensive groundwater pumping continues, the land is sinking more rapidly and this puts nearby infrastructure at greater risk of costly damage.” 

Sinking land, known as subsidence, has occurred for decades in California because of excessive groundwater pumping during drought conditions, but the new NASA data shows the sinking is happening faster, putting infrastructure on the surface at growing risk of damage. NASA obtained the subsidence data by comparing satellite images of the Earth’s surface over time.

Land near Corcoran in the Tulare basin sank 13 inches in just eight months—about 1.6 inches per month. One area in the Sacramento Valley was sinking approximately half-an-inch per month, faster than previous measurements. NASA also found areas near the California Aqueduct sank up to 12.5 inches, with eight inches of that occurring in just four months of 2014.

 

The increased subsidence rates have the potential to damage local, state, and federal infrastructure, including aqueducts, bridges, roads, and flood control structures. Long-term subsidence has already destroyed thousands of public and private groundwater well casings in the San Joaquin Valley. Over time, subsidence can permanently reduce the underground aquifer’s water storage capacity...

In response to the new findings, and as part of an ongoing effort to respond to the effects of California’s historic drought, the Governor’s Drought Task Force has committed to working with affected communities to develop near-term and long-term recommendations to reduce the rate of sinking and address risks to infrastructure. This action builds on the historic Sustainable Groundwater Management Act, enacted by Governor Edmund G. Brown Jr. in September 2014, which requires local governments to form sustainable groundwater agencies that will regulate pumping and recharge to better manage groundwater supplies.

“Groundwater acts as a savings account to provide supplies during drought, but the NASA report shows the consequences of excessive withdrawals as we head into the fifth year of historic drought,” Director Cowin said. “We will work together with counties, local water districts, and affected communities to identify ways to slow the rate of subsidence and protect vital infrastructure such as canals, pumping stations, bridges, and wells.”

 

The Department of Water Resources is also launching a $10 million program to help counties with stressed groundwater basins to develop or strengthen local ordinances and conservation plans. This funding comes from the statewide Water Bond passed last year, and applications for funding will be posted in the coming days. This year’s budget passed in July also enables streamlined environmental review for any county ordinance that reduces groundwater pumping.

NASA will also continue its subsidence monitoring, using data from the European Space Agency’s recently launched Sentinel-1 mission to cover a broader area and identify more vulnerable locations.

DWR also completed a recent land survey along the Aqueduct--which found 70-plus miles in Fresno, Kings, and Kern counties sank more than 1.25 feet in two years--and will now conduct a system-wide evaluation of subsidence along the California Aqueduct and the condition of State Water Project facilities. The evaluation will help the department develop a capital improvement program to repair damage from subsidence. Past evaluations found that segments of the Aqueduct from Los Banos to Lost Hills sank more than five feet since construction. 

The report, Progress Report: Subsidence in the Central Valley, California, prepared for DWR by researchers at the National Aeronautics and Space Administration’s (NASA’s) Jet Propulsion Laboratory, is available here:

 

http://water.ca.gov/waterconditions/index.cfm

 

 

 

 

 

8-18-15

Orange County Register

Drought fallowing half-million acres in California in 2015

Ellen Knickmeyer/Associated Press

http://www.ocregister.com/articles/water-678199-california-state.html

– California’s now 4-year-old drought will cost state agriculture $1.84 billion in 2015, researchers estimated in a study Tuesday from the University of California at Davis.

The biggest chunk of that cost will come from the fallowing of 542,000 acres that lack water for irrigation, the study said. That’s about one-fifth more land than drought forced out of production last year, researchers noted.

Agriculture, water and economic experts at the university stressed the extent to which farmers in California — the country’s leading agriculture state — are relying on groundwater pumping to make up for dwindling stores of water in state rivers, creeks, reservoirs and snowpack.

Overall in 2015, farmers have nearly 9 million fewer acre feet of surface water for irrigation, out of the 28 million acre feet that state water officials say California agriculture uses in an average year. An acre foot is the amount an average California household uses in a year, and it is one of the standard units of measurement for water.

To make up for that, farmers and ranchers are pumping an additional 6 million acre feet of water for irrigation out of the state’s underground water aquifers this year, Tuesday’s study said. The study adds to findings — from sources ranging from overbooked drillers of water wells to groundwater studies by NASA scientists — that California, in drought, is pumping up its groundwater at an alarming rate.

The study calls the rate of pumping of groundwater in the drought unprecedented. While California lawmakers in 2014 passed the state’s first legislation to try to protect key aquifers from getting pumped dry of useable water, the state’s 27-year timeline for bringing groundwater pumping under regulation is likely too long, the University of California at Davis researchers said.

The drought will hit farm workers as well as farm owners in 2015, costing 10,100 seasonal farm jobs, the study said. Agriculture overall employs more than 400,000 workers in California.

The study noted one area of agriculture that is booming despite the drought. The state’s acreage of almonds and walnuts has grown by 200,000 since 2010, despite constraints on water, the study said. Economists say growing demand from consumers in China for nuts as snack food is driving the almond-orchard boom here.

Agriculture consumes about 80 percent of all water from rivers, lakes and other sources that Californians use, and it accounts for about 2 percent of the state’s economy.

 

12-16-14

NASA.gov

NASA Analysis: 11 Trillion Gallons to Replenish California Drought Losses

https://www.nasa.gov/press/2014/december/nasa-analysis-11-trillion-gallons-to-replenish-california-drought-losses

It will take about 11 trillion gallons of water (42 cubic kilometers) -- around 1.5 times the maximum volume of the largest U.S. reservoir -- to recover from California's continuing drought, according to a new analysis of NASA satellite data.

The finding was part of a sobering update on the state's drought made possible by space and airborne measurements and presented by NASA scientists Dec. 16 at the American Geophysical Union meeting in San Francisco. Such data are giving scientists an unprecedented ability to identify key features of droughts, data that can be used to inform water management decisions.

A team of scientists led by Jay Famiglietti of NASA's Jet Propulsion Laboratory in Pasadena, California used data from NASA's Gravity Recovery and Climate Experiment (GRACE) satellites to develop the first-ever calculation of this kind -- the volume of water required to end an episode of drought.

Earlier this year, at the peak of California's current three-year drought, the team found that water storage in the state's Sacramento and San Joaquin river basins was 11 trillion gallons below normal seasonal levels. Data collected since the launch of GRACE in 2002 shows this deficit has increased steadily.

"Spaceborne and airborne measurements of Earth's changing shape, surface height and gravity field now allow us to measure and analyze key features of droughts better than ever before, including determining precisely when they begin and end and what their magnitude is at any moment in time," Famiglietti said. "That's an incredible advance and something that would be impossible using only ground-based observations."

GRACE data reveal that, since 2011, the Sacramento and San Joaquin river basins decreased in volume by four trillion gallons of water each year (15 cubic kilometers). That's more water than California's 38 million residents use each year for domestic and municipal purposes. About two-thirds of the loss is due to depletion of groundwater beneath California's Central Valley.

In related results, early 2014 data from NASA's Airborne Snow Observatory indicate that snowpack in California's Sierra Nevada range was only half of previous estimates.

The observatory is providing the first-ever high-resolution observations of snow water volume in the Tuolumne River, Merced, Kings and Lakes basins of the Sierra Nevada and Uncompahgre watershed in the Upper Colorado River Basin.

To develop these calculations, the observatory measures how much water is in the snowpack and how much sunlight the snow absorbs, which influences how fast the snow melts. These data enable accurate estimates of how much water will flow out of a basin when the snow melts, which helps guide decision about reservoir filling and water allocation.

"The 2014 snowpack was one of the three lowest on record and the worst since 1977, when California's population was half what it is now," said Airborne Snow Observatory principal investigator Tom Painter of JPL. "Besides resulting in less snow water, the dramatic reduction in snow extent contributes to warming our climate by allowing the ground to absorb more sunlight. This reduces soil moisture, which makes it harder to get water from the snow into reservoirs once it does start snowing again."

New drought maps show groundwater levels across the U.S. Southwest are in the lowest two to 10 percent since 1949. The maps, developed at NASA's Goddard Space Flight Center in Greenbelt, Maryland, combine GRACE data with other satellite observations.

"Integrating GRACE data with other satellite measurements provides a more holistic view of the impact of drought on water availability, including on groundwater resources, which are typically ignored in standard drought indices," said Matt Rodell, chief of the Hydrological Sciences Laboratory at Goddard.

The scientists cautioned that while the recent California storms have been helpful in replenishing water resources, they aren't nearly enough to end the multi-year drought.

"It takes years to get into a drought of this severity, and it will likely take many more big storms, and years, to crawl out of it," said Famiglietti.

NASA monitors Earth's vital signs from land, air and space with a fleet of satellites and ambitious airborne and ground-based observation campaigns. The agency develops new ways to observe and study Earth's interconnected natural systems with long-term data records and computer analysis tools to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

 

8-19-15

Stockton Record

Water pumping has Valley land sinking

While San Joaquin County doesn't experience the kind of extreme sinking described by scientists in Wednesday's report, state officials in related news declared that groundwater in the county remain...

By Scott Smith
The Associated Press


http://www.recordnet.com/article/20150819/NEWS/150819640/-1/A_OPINION

FRESNO — Vast areas of the Central Valley are sinking faster than in the past as massive amounts of groundwater are pumped during the historic drought, state officials said Wednesday, citing new research by NASA scientists.

The data shows the ground is sinking nearly two inches each month in some places, putting roads, bridges and vital canals that deliver water throughout the state at growing risk of damage.

The sinking is much worse south of San Joaquin County, near El Nido and Corcoran. Although groundwater levels are falling in San Joaquin County as well, this area has not experienced such significant sinking, one local official said Wednesday.

Sinking land has occurred for decades in California because of excessive groundwater pumping during dry years, but the new data shows it is happening faster as the state endures its fourth year of drought.

"We are pumping at historic levels," said Mark Cowin, head of the California Department of Water Resources. He added that groundwater levels are dropping to record levels — up to 100 feet lower than previously recorded.

Scientists at NASA's Jet Propulsion Laboratory did the research using images taken over time from satellites and airplanes.

California is the nation's leading agriculture state, but drought has put one-fifth more land out of production this year than last year.

Gov. Jerry Brown signed historic legislation last year that requires monitoring of groundwater pumping. However, local officials have until 2020 and in some cases until 2022 to write their management plans, so it could take another decade or two before California has a handle on groundwater use, Cowin said.

"I don't think we can end overdraft or subsidence overnight," he said. "We do need to take action."

Meanwhile, the Department of Water Resources is launching a $10 million program to help counties with stressed groundwater basins to develop or strengthen local ordinances and conservation plans.

The NASA data shows land near the city of Corcoran sank 13 inches in eight months, and part of the California Aqueduct dropped eight inches in four months last year. The aqueduct spans hundreds of miles and provides water to millions of people and vast areas of farmland.

Farmers in the Central California Irrigation District have spent $4.5 million to raise the walls on a canal and intend to pay $2.5 million to raise a bridge above the water.

"It's a vivid picture of what subsidence can do," said Christopher White, manager of the district that serves 1,900 farmers, who grow tomatoes, cotton, fruit, almonds and other crops in three counties.

Long-term subsidence has already destroyed thousands of public and private groundwater well casings in the San Joaquin Valley. Over time, subsidence can permanently reduce the underground aquifer's water storage capacity.

Lester Snow, executive director of the California Water Foundation, which promotes water policy, urged more immediate action. He said state and federal officials should also offer local agencies financial incentives to reduce reliance on groundwater.

Investments are also needed in storm water capture during wet winters to offset heavy reliance on groundwater, Snow said.

"As long as this continues, we risk further damage to roads, levees and buildings," he said. "There is no time to waste."

Brandon Nakagawa, San Joaquin County's water resources coordinator, said the sinking isn't as severe here because of different geological conditions. What's more, about $700 million has been spent over the past three decades bringing more river water to the county, which reduces the need to pump groundwater.

Delta levees and islands are prone to sinking, but that's due to the peat soils found in the estuary and is not a result of groundwater pumping.

 

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