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Oakdale Irrigation District water-table issue resurfaces

Irrigation leaders were pleased to learn in a recent meeting that groundwater levels in the Oakdale Irrigation District’s wells have dropped less than 41/2 inches in the past year, on average, despite record pumping.

But those numbers were based on data from only three-fourths of OID’s deep wells, a Modesto Bee analysis found.

Data also show that the water table has been steadily dropping in most OID wells over the past decade – about 13 feet total.

And both findings – all bickering aside over OID’s pumping while arranging to sell river water to wealthy out-of-county buyers – are inconclusive, one expert said.

OID officials steadfastly have defended a plan to pay farmers willing to fallow land with profits from selling to Fresno-area buyers the water that would have been used locally. Most of the money would be invested in overdue upgrades to water systems, enabling growers to use less in future years while freeing up more water.

The deal was put on hold because of a detractor’s legal threat combined with prolonged drought, which could prompt the OID board to cap water deliveries for the first time in its 105-year history. But before it stalled, the $4 million-a-year deal drew scorn from critics who questioned the wisdom of exporting a precious resource, especially if that requires OID to increase groundwater pumping – at the peril of neighbors.

By one count, more than 100 shallower domestic wells have gone dry in various clusters in the eastern half of Stanislaus County, including several near Oakdale and Valley Home, costing many owners $20,000 or more to drill deeper new wells for tap water.

Groundwater levels in three of OID’s four Valley Home wells have plunged more than 10 feet in the past decade, The Bee’s analysis shows. Neighbors have no way to prove whether OID’s increased pumping contributed to their woes, or a smattering of private industrial wells feeding almond orchards that have sprung up around the rural community.

“I think it’s a combination of both,” said Valley Home resident Mike Tozzi, whose well dried up last summer along with those of eight neighboring families. It’s unfortunate, he said, that OID officials would “use groundwater in order to save their surface water” in hopes of selling some.

While laying their plan to export mountain runoff, OID leaders last year pumped a record 17,000 acre-feet of groundwater, about double the normal amount.

They have maintained – in letters, newsletters, press releases and on The Bee’s editorial page – that OID never planned to pump and sell groundwater.

OID General Manager Steve Knell has explained that district wells add groundwater to canals in strategic “constriction points,” boosting flow to move canal water to fields. The district acknowledges pumping more than usual last year – just like every water agency in drought-plagued California. And OID’s record 17,000 acre-feet is a pittance compared with others, Knell says.

On Tuesday, Knell scoffed at “all the hype last year over how much we were pumping” while telling board members that some groundwater levels in 26 OID wells had come up since this time last year, some had dropped a few feet and the overall average was a 4.4-inch decline.

Board member Frank Clark noted that critics continue “beating us up” in social media.

“Facts get in the way of your perception,” Knell said. “All we do is provide facts. What they do with the facts is beyond our control.”

A closer look shows that OID obtained data from only 24 wells, and four are privately owned. OID uses the data in water-table reports to a state agency, but the district can take no credit or blame for their operations. Two more were excluded because they were installed after numbers were recorded a year ago.

Additionally, OID has nine more older industrial wells that pump groundwater but whose levels are not included because they don’t have modern recording instruments, said Eric Thorburn, OID’s water operations manager.

A news release after the board meeting made no mention of the private wells, new wells or unmonitored wells.

Knell said there is merit in telling the public exactly what OID tells the state. “It’s for consistency. If you’re tweaking data and being selective, people criticize you for that,” he said.

Walter Ward, the county’s water resources manager, took a look at the numbers and said they don’t mean much. A useful analysis, he said, would factor in location, construction information such as well type and depth, and data reflecting how much water was actually pumped.

“Otherwise,” he concluded, “local scale impacts can be masked.”

Groundwater levels from the Modesto Irrigation District show a generally similar drop in its irrigation wells – 11 feet in the past 14 years. That doesn’t count drainage wells on the west side of its boundaries, which are used in lowering the much higher groundwater level to keep roots dry so crops can grow.

Despite OID’s record-high pumping last season, its annual average since the district began exporting water in 1998 has been 6,762 acre-feet, Knell said, compared with 8,513 acre-feet over the previous 16 years.

However, he acknowledged a steady decline in Oakdale’s water table since the district started drilling wells several decades ago. The issue should be addressed, but everything depends on a definition of sustainability that has yet to be agreed upon, Knell said.

OID’s numbers show double-digit percentage point drops in 10 of 15 district wells monitored over the past decade. The most dramatic declines – 271/2 feet and 291/2 feet – came from two wells along district canals but just outside OID boundaries, in the Paulsell Valley northeast of Waterford. Farmers have blanketed that area with new orchards.

A recent U.S. Geological Survey study said water tables are sinking faster in the Central Valley than anywhere else in the United States, and an agency expert blamed overpumping on the drought and a sudden surge in profitable but thirsty almond trees.

Farmers in southern parts of the San Joaquin Valley have lowered the water table as much as 400 feet, resulting in subsidence, or collapsing soil, that has damaged roads and canals and sometimes made it impossible for the earth to reabsorb water.

Stanislaus leaders are moving toward creation of a groundwater management agency that could impose pumping restrictions or look for ways to replenish aquifers. Meanwhile, a recent rush on well permits in anticipation of restrictions seems to have slowed; Stanislaus farmers have applied for 32 industrial-size wells this year, compared with 109 by this point in 2014.

Bee staff writer Garth Stapley can be reached at gstapley@modbee.com or (209) 578-2390.

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