Groundwater Levels Critical Before Drought

LOS ANGELES (CN) - California says groundwater in 21 basins in the state has dropped to critical levels, but that its findings reflect 6-year-old data rather than the current and severe drought conditions.

At a Wednesday morning meeting hosted by the Metropolitan Water District in Los Angeles, Department of Water Resources geologist Mary Scruggs presented a draft list identifying groundwater basins and sub-basins that were critically depleted because of excessive water pumping.

Scruggs' presentation to members of the California Water Commission came as NASA released findings that groundwater pumping is causing land in the San Joaquin Valley to sink at the fastest rate in recorded history.

Under a drought package unveiled by Gov. Jerry Brown last year, agencies managing critical basins in the state must create a groundwater sustainability plan by 2020, two years earlier than basins the state considers high or medium priority but not critical.

The department evaluated about 40 percent of those basins with funding under the Sustainable Groundwater Management Act, or SGMA, Scruggs said.

Scruggs told the commission that the agency had looked at data for 127 basins but said the report was limited to a 10-year period from 1989 to 2009. California's drought began in 2012.

"The basins not identified as critically overdrafted could be overdrafted or they could be fine but we did not go out and look for overdraft. We looked for the critically overdrafted extreme," Scruggs said. "Due to the current drought conditions that have been happening, some of those basins that are critically overdrafted - or maybe they are overdrafted - they could be in that condition. As I said, we only looked at the base period."

During public comment, Environment Now staff attorney Caryn Mandelbaum questioned why the department had excluded the drought period from its report.

"There have been many more wells drilled during this [drought] period because of reductions in surface-water deliveries and because there's still an opportunity to continue to drill wells unregulated before SGMA is enacted," Mandelbaum said. "So I imagine that many of those basins where they've already been experiencing overdraft - and they are now subject to potentially more overdraft because more wells are being drilled and pumped - would fall into this critical level, if they hadn't been before."

Scraggs said the reason basins were not included during the drought period was because a provision of SGMA states that depletion during a period of drought does not reliably establish chronic groundwater levels.

"For what we were tasked to do for defining critically overdrafted basins, with respect to SGMA, it was outside the drought period," Scraggs said.

Several Central Valley water basins are included on the list, including a new addition in Paso Robles.

The draft list states that from 1997 to 2013 the groundwater table in portions of the basin declined more than 70 feet because of a shift from farming alfalfa and livestock to vineyards and wineries.

"The basins on the draft list show obvious and significant negative impacts from chronic groundwater pumping. Those impacts include seawater intrusion, land subsidence, groundwater depletion, and chronic drop in groundwater levels," the department said in documents at the water commission's website.

Department of Water Resources may take a basin off the list if an agency submits supporting data before the list becomes final in October.

The state funded a similar report in 2003, relying on 23-year-old data that had identified 11 critical basins.

Scruggs said the state had identified basins in the central region because of Californians' reliance on them as water sources.

"In those high and medium priority basins, based on the data that we had, it ended up being that it covers 88 percent of the overlying population and it covers 96 percent of the groundwater being used in the state. So, that is where groundwater is critical throughout the state," Scraggs said.

"To expect all the high-priority basins to come in as critically overdrafted wouldn't be right because it's an importance of groundwater. So, if you have a highly important basin and it's being managed well, one would not expect it to be critically overdrafted. And ideally we'd like all none of them to be critically overdrafted," she said.

"That doesn't mean those areas don't have problems and it doesn't mean that other basins other than the 21 don't have issues to deal with," Scraggs said.

The Department of Water Resources will hold a public meeting to discuss in more detail the draft results on Aug. 25, in the Fresno suburb of Clovis, California.

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