‘I am curious about something I see on Coffee Road during my walks and travels,” said James Calvillo of Modesto. “Near Downey High School, at the south end of the property near the sidewalk, there’s a fairly large pipe pouring water into a huge drain. There is a sign placed there by the city that says something about flushing for water quality or something.
“Is this fresh water just being put down the drain? If it is good water, it seems a shame since we are in a bad drought.”
I checked, and it did look like a gusher going down the drain. But it’s not exactly “good water.”
Dave Savidge, Modesto’s water systems manager, said the water was being flushed from the city’s well No. 18, which is at Locke Road and Brighton Avenue. That well was taken offline in November 2007 because the level of nitrates was above the drinking-water standards. The well can provide up to 1.4 million gallons of water per day.
Modesto has 96 working wells and two more that “have been offline for several years” and are being returned to service, Savidge said. There are 12 other wells that “are offline permanently because of poor water quality or have been abandoned.”
In addition to the wells, Modesto uses surface water from the Modesto Irrigation District to supplement its water supply. At present, Savidge said, the city uses about 73 percent groundwater from wells and 27 percent surface water.
Enter the drought.
This spring, because the Modesto Irrigation District made “reductions in surface water in part by the drought conditions,” the city decided to try to bring well No. 18 back online.
“To try and make this happen, city crews installed a flushed line and a sewer connection at Coffee Road in the beginning of April,” Savidge said. “By flushing continuously, we anticipate the nitrate level to decrease below the drinking water standards. Once achieved, the California Department of Public Health reviews sampling data and will make the decision to either use the well for our distribution system or recommend some kind of treatment before entering our distribution system.”
So, in theory at least, it works like this: By taking tainted water out of the unused well, more pure water should flow into the well, thus making it more potable. Savidge said studies show that nitrate levels continue to climb in unused wells, while siphoning them out tends to improve the quality.
In the meantime, the approximately 80,000 gallons of water that have been flushed out of the well since it was reopened have gone into the sewer system. The city’s wastewater division treats and reuses the water for irrigation on fields that are leased to farmers near the Jennings Plant Facility, Savidge said.
So it’s not going to waste.
Actually, there’s a kind of P.S. to this story. Because the well was an older one, the pump gave out in late May. When city workers replaced the pump, the city decided to move the flushing pipe from Coffee Road to an alley near Rose Avenue and Locke Road. The larger sewer system was more capable of handling it there, Savidge said. So the big pipe on Coffee Road is no longer gushing water.
“Once at acceptable drinking water standards, we will be able to release water to our distribution system. This could be a couple of weeks to a month,” Savidge added.