DEP proposes seasonal chlorination/dechlorination at two Flushing Creek outfalls; hearing closes with no public testimony

The New York City Department of Environmental Protection on Thursday presented a plan to disinfect combined sewer overflow (CSO) discharges into Flushing Creek by installing seasonal chlorination and dechlorination facilities at two outfalls, TI‑10 and TI‑11, DEP staff told the Queens Borough President’s land use public hearing.

“We have proposed for Flushing Creek a disinfection program,” Deputy Commissioner Angela Licata said in the presentation, describing the proposal as a cost‑effective alternative to very large storage tunnels. DEP officials and consultants said disinfection would target the recreation season (May 1–Oct. 31) and be controlled to meet New York State’s total residual chlorine limit of 0.1 milligram per liter.

DEP and its consultants presented results from hydrologic, hydraulic and computational fluid dynamics modeling that, they said, show the system could disinfect about 91% of CSO flows that reach the creek during the recreation season, exceeding the LTCP target of 88%. “We believe we can achieve about 91% disinfection,” Arcadis engineer Timothy McDonald said while reviewing modeled overflow frequency and dilution assumptions.

Why disinfection? DEP said Flushing Creek receives more than 1 billion gallons of CSO annually, making a storage…