RIVERBANK -- About 1,500 gallons of chlorinated water spilled into the Stanislaus River this week after a sewer lift station failed, but preliminary tests show the water had minimal impact on the river, a city official said.
The water had been used to disinfect an 8-inch water main for a low-income senior housing complex that is being built on Orange Avenue along the river. The water was being disposed of through the sewer system.
Development Services Director J.D. Hightower said the spill happened Monday morning after the volume of water overwhelmed the River Cove sewer lift station and the water overflowed through three manholes. Hightower said the city was able to keep about 500 gallons of the chlorinated water out of the river.
Hightower said workers building the senior housing complex had disinfected the water main days earlier and discharged the water through the sewer system without any problems.
"It's an unfortunate incident," Hightower said, "but based on preliminary tests, there has been minimal impact to the river."
The results of an additional test should be back in several days.
Hightower said it is more than likely that some raw sewage was part of the spill that entered the river. He said the level of chlorination in the water that spilled into the river was similar to the level of chlorination in swimming pools.
Chlorine is highly toxic for fish and aquatic life, said Janna Rinderneck, staff environmental scientist with the California Department of Fish and Game.
While she could not speak about this incident, Rinderneck said such factors as the concentration of the chlorine and how much of it degraded while passing through the sewer system would have affected the spill.
Hightower said Riverbank notified Stanislaus County Environmental Health, the state Office of Emergency Services and the Regional Water Quality Board about the spill.
Depending on what investigators find, Riverbank could be cited and-or required to change how it disposes of water in cases such as this, Hightower said.
Bee staff writer Kevin Valine can be reached at firstname.lastname@example.org or (209) 578-2316.