OAKDALE — More than 75 planning commissioners and officials from throughout Stanislaus County spent Saturday morning learning about the water issues facing their communities.
“The Coming Age of Water Supply” workshop painted a sometimes bleak picture of problems city water systems must overcome to continue providing Stanislaus residents with enough safe, reliable and affordable water.
Everyone in Stanislaus now drinks groundwater, but cities need to diversify their water supplies, advised Nick Pinhey, Modesto’s former public works director who now teaches at California State University, Stanislaus.
“You don’t want to be tied down to one source of water and then have it fail,” Pinhey warned. “You need backup systems at all times” to ensure water can be delivered without interruption.
Pinhey said there’s lots of competition for water these days because it is becoming increasingly scarce in California, especially during severe droughts like this one.
“Whether you buy into climate change or not, it’s something you have to plan for,” Pinhey told the planning commissioners. He noted how during the Middle Ages geological records and tree rings show there were “mega-droughts” in California that lasted as long as 140 years.
Pinhey shared maps showing where San Joaquin Valley groundwater basins have been depleted in recent years, including spots where there’s been so much overdraft that the land’s surface has subsided.
Although conditions aren’t that bad in Stanislaus, Pinhey said, there are problems that must be addressed, such as groundwater contamination and increasing demand caused by population growth.
“Groundwater quality and groundwater quantity go hand in hand,” Pinhey said. The pumping of Stanislaus’ wells may increase as more surface water gets diverted to protect the environment, such as preventing saltwater intrusion into the Sacramento-San Joaquin Delta, he said.
State proposals to increase water flows down the Tuolumne, Stanislaus and Merced rivers, and thus to reduce water diversions for agriculture, concern John Davids, the Modesto Irrigation District’s civil engineering manager.
“The state water board is proposing 35 to 40 percent unimpaired flows down the (San Joaquin River tributaries), which would mean taking 100,000 acre-feet of water from the MID,” Davids said. “That’s 50 percent of the water used on our farms every year.”
The MID currently supplies water from snowmelt and the Tuolumne River to meet the domestic needs of about half of Modesto’s residents and businesses. That surface water now is mixed with well water. If the state requires more water to flow down the river instead, then Davids warns that the MID would not be able to provide as much surface water to the city.
“That would increase Modesto’s reliance on groundwater,” Davids explained.
Stanislaus cities account for about 10 percent of water demand in the county, Pinhey estimated. About 45 percent of water is used by agriculture and 45 percent is used for environmental purposes.
But competition for water both above and below ground is increasing. That helped persuade the Stanislaus County Board of Supervisors this year to hire a new water resources manager and to appoint a Water Advisory Committee.
Walt Ward, who got that new post, told the planning commissioners that everyone now is focused on groundwater sustainability.
Ward and the county’s 21-member water committee have been working this spring to draft proposals for managing Stanislaus’ groundwater supply, particularly in the rural eastern and northeastern parts of the county where nut orchards and water wells have multiplied.
Ward said hydrologists used by farmers there have assured him “they know what they’re doing” and that there’s enough groundwater to irrigate those orchards.
The three-year drought and statewide reports about falling groundwater levels, however, have people worried.
“We’re in for a difficult summer,” predicted Ward, noting how problems with water wells may emerge in months to come.
However, Ward said, during his three months on the job he hasn’t gotten “a single phone call” from anyone saying his well has gone dry.
To report such trouble, Ward said, well owners can phone him at (209) 525-6710.
Bee staff writer J.N. Sbranti can be reached at email@example.com or (209) 578-2196.