Much of the critics’ focus on the State Water Resources Control Board proposal to let more water flow down the Stanislaus, Tuolumne and Merced rivers has been on how it would devastate agriculture and our ag-dependent economy in the Northern San Joaquin Valley.
But Modesto Utilities Director Larry Parlin says the proposal is not good news for the residents, businesses, schools, hospitals and others who depend upon the city for drinking water. In a normal year, Modesto gets half of its drinking water from the Tuolumne River through the Modesto Irrigation District. Wells provide the rest.
The amount from the Tuolumne has been cut to roughly a third of the city’s supply in recent years because of the drought as MID has reduced what it provides the city and farmers. Modesto has been getting river water since 1995 and is the only Stanislaus County city that supplements its well water with river water.
That has allowed Modesto to recover its groundwater levels. But Parlin said that trend will reverse if Modesto gets less river water and has to pump more groundwater. He noted that using more well water is counter to a state law that requires the sustainable management of groundwater supplies.
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He added that groundwater may become more expensive or there could be less of it if the water board adopts a more stringent drinking water standard for a contaminant called 1, 2, 3-trichloropropane, which is a toxic remnant from a soil fumigant used by farmers decades ago. He said the higher standard will require expensive treatment to wells or require them to be shut down.
Then there is the question of what less river water means for the $106 million expansion of MID’s Modesto Regional Water Treatment Plant, which supplies the city with drinking water from the Tuolumne River. The expansion was completed this year and doubles the plant’s capacity to 60 million gallons a day. Modesto is paying for the expansion, which was conceived more than a decade ago, well before the current drought, and based on population growth projections that have not materialized.
“The city will continue to pursue all opportunities to maximize the water plant production regardless of actions taken by the state,” Parlin said in an email. “This includes working with MID and others to obtain additional surface water supplies that may become available as the economics of water continue to evolve. It is in the best interest of our customers to utilize existing infrastructure to provide a reliable drinking water supply and prevent the overdraft of groundwater.”
The State Water Resources Control Board proposal is to increase what are called the rivers’ unimpaired flows, which would result in less water staying in the Northern San Joaquin Valley. Advocates say the proposal’s benefits include helping the environmentally fragile Sacramento-San Joaquin Delta.
The board is holding a series of hearings on its proposal. One is scheduled for Dec. 20 at Modesto Centre Plaza. Parlin said the city has been allotted 20 minutes to talk about the proposal’s impacts on Modesto. Parlin said he expects Mayor Ted Brandvold and other City Council members to speak.
The board could make a decision on its proposal in July.
Kevin Valine: 209-578-2316