Peripheral tunnels won't address subsidence threat to Central Valley

By Dan Bacher | November 24, 2013 | A U.S. Geological Survey report released on Thursday revealed that land subsidence caused by ov...

By Dan Bacher | November 24, 2013 |

A U.S. Geological Survey report released on Thursday revealed that land subsidence caused by over drafting of ground water supplies in the San Joaquin Valley has resulted in a threat to water delivery systems, including the Delta Mendota-Canal and the California Aqueduct. 

Proponents of the Bay Delta Conservation Plan (BDCP) to build the peripheral tunnels used the report's release as yet another opportunity to promote the $54.1 billion project as the "solution" to California's water problems, while tunnel opponents said the tunnels will do nothing to address the land subsidence threat. 

The report, "Land Subsidence along the Delta-Mendota Canal in the Northern Part of the San Joaquin Valley, California, 2003–10," by Michelle Sneed, Justin Brandt, and Mike Solt, reveals how extensive groundwater pumping from San Joaquin Valley aquifers is increasing the rate of land subsidence, or sinking. 

"This large-scale and rapid subsidence has the potential to cause serious damage to the water delivery infrastructure that brings water from the north of the valley to the south where it helps feed thirsty cropland and cities," according to the USGS. "The subsidence is occurring in such a way that there may be significant operational and structural challenges that need to be overcome to ensure reliable water delivery." 

The report concentrates on subsidence in an original study area along the Delta-Mendota Canal in the northern San Joaquin Valley, but also includes data from a subsequently discovered and much larger subsidence area that touches the canal on the southwest. 

"This subsidence is reducing the capacity of the Delta-Mendota Canal, the California Aqueduct, and other canals that transport floodwater and deliver water to agriculture, cities, industry and wildlife refuges," the USGS stated. 

"The USGS report was commissioned by the U.S. Bureau of Reclamation to learn more about the challenges we face due to subsidence. It will help us take additional proactive measures to ensure efficient delivery of water to the San Joaquin Valley," said David Murillo, Mid-Pacific regional director of the Bureau of Reclamation. 

For the complete report, go to: 

Phil Isenberg, Chair of the Delta Stewardship Council, who also served as the Chair of the Delta Vision Blue Ribbon Task Force and the Marine Life Protection Act (MLPA) Initiative Blue Ribbon Task Force to create alleged "marine protected areas" on the Central Coast, was the first to respond to the report's release in a statement. 

Isenberg employed the report to promote the California Water Action Plan and the Delta Stewardship Council’s "Delta Plan," both of which strongly support the Bay Delta Conservation Plan to build the twin tunnels. There are currently seven lawsuits by water contractors, environmentalists, Indian Tribes and fishing groups against the severely-flawed "Delta Plan" proceeding through the courts. 

“This report reinforces the urgency of understanding and better managing California’s groundwater basins," said Isenberg. "The amount and widespread nature of the subsidence found by the USGS is truly alarming and shows that cutbacks in surface water deliveries because of drought or environmental concerns cannot sustainably be replaced or exceeded by continual groundwater extractions." 

"The report also underscores the urgency of actions and recommendations included in the draft California Water Action Plan and the Delta Stewardship Council’s recently adopted Delta Plan," said Isenberg. 

Restore the Delta (RTD) responded to the release of the report by saying the Brown Administration’s massive water export tunnels would "do nothing" to address this threat to the Central Valley. Restore the Delta Executive Director Barbara Barrigan-Parrilla said, “San Joaquin Valley’s land subsidence is the real threat to California’s water delivery system.” 

She noted that the report shows that the Westlands and Kern Water District mega-growers are engaged in "unsustainable growing of permanent crops on arid land, and that the governor’s Peripheral Tunnels don’t address this root cause of the state’s water problem." 

"The San Joaquin Valley’s complicated system of moving water around depends on maintaining water levels and flows in the Delta-Mendota Canal and in irrigation canals," according to Barrigan-Parrilla. "But groundwater overdraft in parts of the region is causing the land to subside and the canals to sink. One dam and canal in western Madera County are sinking six inches a year, so the dam won’t be high enough for gravity to push water down the canal." 

An engineering geologist with the Department of Water Resources says that two areas subsided up to a foot a year for the past four to five years. A USGS hydrologist says the lining of the Delta Mendota Canal is actually buckling in some places. One canal has lost 50% of its capacity due to subsidence, according to Barrigan-Parrilla. 

"Yet, water rate payers are being asked to subsidize construction of the Brown Administration’s peripheral tunnels so that big corporate agribusinesses in the San Joaquin Valley can prop up its unsustainable economic and environmental model," she explained. 

“How can California water ratepayers be expected to pay for the construction of the Peripheral Tunnels when the state’s existing water delivery infrastructure is breaking down?” said Barrigan-Parrilla. “Exporters have spent millions of dollars creating a public campaign that they are the victims, and that the Delta is the weak link, but these water takers were never supposed to plant permanent crops." 

Barrigan-Parrilla concluded, "They’ve exhausted their own groundwater supply, and now they are coming after the Delta and upstream rivers to support farms that are not environmentally and economically sustainable. Sending them water is like enabling a drug addict. Is the state’s entire water supply to be sacrificed for almonds to export to China?"

The construction of the $54.1 billion tunnels would hasten the extinction of Sacramento River chinook salmon, Central Valley steelhead, Delta smelt, longfin smelt and green sturgeon, as well as imperiling the steelhead and salmon populations of the Trinity and Klamath rivers. 

However, the way the state and federal governments are managing Delta water, many of these fish could become extinct before construction of the tunnels ever begins. The 2013 Fall Mid Water Trawl (FMWT) abundance indices recently released by the California Department of Fish and Wildlife reveal that populations of Delta fish are only a small fraction of their historical abundance before Delta water exports began. 

The indices for Delta smelt (7), striped bass (23), threadfin shad (70), and American shad (135) were the second, second, third and second lowest, respectively, in the 46 years of the survey. The index for longfin smelt (36) was comparable to the very low indices of recent years. 

Delta smelt, striped bass, longfin smelt, American shad and threadfin shad populations in 2013 have plummeted 98.9, 99.6, 99.7, 89.1, 98.1 percent, respectively, from the average of the initial six years of the survey (1967-1972), according to Bill Jennings, Executive Director of the California Sportfishing Protection Alliance (CSPA) and a board member of the California Water Impact Network (C-WIN) and Restore the Delta. The Sacramento splittail index was not released, but the 2012 September-October index was zero. 

Massive water exports to corporate agribusiness interests on the west side of the San Joaquin Valley, combined with increases in toxic chemicals and invasive species, have resulted in these fish population collapses, according to state and federal scientists. 

Yet Brown is not only promoting the construction of the twin tunnels, but on September 20 signed legislation, Senate Bill 4, giving the green light to the expansion of fracking in California. This will only result in increasing pollution of already contaminated ground water and surface water resources with the toxic brew of fracking chemicals that oil companies refuse to disclose. 

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