MODESTO — Even valley water leaders are talking about the Rim fire.
The fire itself doesn't threaten mountain water going to thousands of farmers and hundreds of thousands of Modesto water customers, all of whom rely on Tuolumne River flows.
But the aftermath could provoke headaches, Modesto Irrigation District board members heard Tuesday.
That's because soot and ash and blackened trees eventually will wash into Don Pedro Reservoir, the main holding pot for the MID and the Turlock Irrigation District, when snow melts next spring.
Tons of icky residue from the burned "lunar landscape look of the land," the Stanislaus County Farm Bureau's Tom Orvis told the board, will settle in Don Pedro, leaving less room for its main mission of storing water.
"Though you don't reside there, your water comes from those counties and (the fire) could affect your ratepayers," Orvis said.
Debris has affected the districts before, after major fires in the Sierra and its foothills, said Walter Ward, assistant general manager for water operations.
Fallout from the Stanislaus Complex fire of 1987 the area's worst, until this year was not immediately evident because of an extended drought, Ward said. But the fire's byproduct slid downstream with a sea of snowmelt in early 1997, long remembered for extensive flooding in Modesto and other valley towns.
The districts have been more concerned about relatively dry winters the past two years. If prayers are answered with abundant snowfall this winter, it could worsen the fire debris problem, Ward said.
The districts have access to tugboats that would deploy floating booms to capture much of the debris when it comes this time, Ward said. Crews would guide logs to the reservoir's banks and burn it or chop it for firewood, he said.
But for now, "I can clearly say our water supply is not threatened," he said.
The Tuolumne provides irrigation for 8,000 growers farming 208,000 acres in both districts. Also, the MID sells treated surface water to the city of Modesto, which mixes it with well water and sells it to customers in Modesto as well as Empire, Salida, Waterford, Hickman, Grayson, Del Rio and small parts of Ceres and Turlock.
The treatment plant provides City Hall with 39 million gallons per day this time of year about maximum capacity, Ward said. That is expected to jump to 66 million gallons per day when a $107.5 mil- lion expansion is complete in a couple of years.
A Don Pedro powerhouse also provides some electricity to the districts' 211,000 customers. The districts are in the middle of a multiyear application for a federal license renewal and fear that some water will be taken to strengthen salmon runs.
San Francisco also has rights to some Tuolumne water. That city's main source nearby Hetch Hetchy Reservoir, supplying tap water to 2.6 million people via tunnels is next to one edge of the Rim fire.
Surface ash is not a problem so far because supply pipes suck from 260 feet down, San Francisco officials say, but they are concerned at the prospect of debris washing down with rain and snowmelt.
In other business, the MID board agreed Tuesday to pay an outside engineering firm $600,000 a year because the district has not been able to attract qualified engineers to its staff, despite substantial raises approved in December for most employees.
Bee staff writer Garth Stapley can be reached at email@example.com or (209) 578-2390.