Routine statewide surface water tests by the state Department of Energy and Environmental Protection show bacteria counts are too high in Wilton’s storm water drains.
The problems had been known previously, but were brought to a head this month when the town released its storm water management plan on the town’s official website, said Traci Iott, supervising environmental analyst for the state.
“Some of the waters there have elevated levels of bacteria,” Iott said by telephone.
Specifically, the average amount of E. coli found in six samples of Wilton’s storm water pipes was more than 17 times the amount listed under the agency’s water quality standards, Iott said. Wilton’s storm water had a geometric mean of 2,202 colony-forming units per 100 milliliters of water. The state DEEP expects the average count to be less than 126 colony-forming units per 100 milliliters, Iott said.
She said the town will have to do some cleanup work and some remediation in order to comply with the orders of its permit.
It’s not a problem unique to Wilton, Iott said. Many towns have high bacteria counts in storm water systems, which could be caused by animal droppings, including those of domestic animals as well as wild geese.
“This is typical, it’s what happens statewide,” she said. “It’s a common water quality issue in Connecticut. We have lots of reports on our website talking about that. The town’s permit work includes work to address bacteria,” she said.
In the town’s storm water management plan, officials say they will counter the problem of bacteria in the storm water system partly by regulating pet droppings, privately and in dog walk areas, and by monitoring waterfowl, among other procedures.
The town will also reduce or eliminate the use of fertilizers on the grass in parks. The streets and parking lots will also be swept and cleaned, particularly in the spring.
Bacteria in storm water is dangerous because it ultimately feeds the Norwalk River and Long Island Sound.