DEP Environmental Protection Invoices, 1999-2001

NYC 9/11 Public Portal Document

January 8, 2001 )epartment of nvironmental Via Facsimile and Federal Express rotection 1-17 Junction Boukva,d Ms. Margaret Duke papa, New York 368-5107 Regional Permit Administrator New York State Department of Environmental Conservation Region 3 oel A. Miele Sr., P. 21 South Putt Comers Road 'ommissioner 1 New Paltz, New York 12561-1696

lark D. Hoffer Re: Alum Treatment of Catskill Water Supply 3eneral Counsel 3ureau of Legal Dear Ms. Duke: Ufalrs -el (718) 595-6555 "ax (718) 595-6543 The New York City Department of Environmental Protection nvw.d.nye.ny.us/dep (DEP) requests the approval of the New York State Department of Environmental Conservation (DEC), pursuant to DEC's emergency authorization authority, for a State Pollutant Discharge Elimination System (SPDES) permit to add alum into the Catskill Water Supply, 6 New York Codes, Rules and Regulations (NYCRR) 621.12. For the reason detailed below, DEP proposes the introduction of Alum into the Catskill Water Supply on an emergency basis in order to control significant turbidity levels in this water supply source.

DEP's proposed addition of alum into the Catskill Water Supply will reduce turbidity levels in the Kensico Reservoir, which in turn will prevent a violation of the turbidity levels for an unfiltered source water, as set forth in the federal Surface Water Treatment Rule and the State ~?r Sanitary Code. Pursuant to both the Surface Water Treatment Rule and f ~ the State Sanitary Code, the turbidity level of a "representative sample of the [system's] source water [taken] immediately prior to the first or only point of disinfection application' cannot exceed 5 nephalometric turbidity • units (NTU). The first and only point of disinfection for the Catskill Water Supply is the Lower Effluent Chamber at the Kensico Reservoir, below the Ashokan Reservoir. In addition, an exceedance of the turbidity " -, level is a violation that may result in a fine under the State Sanitary Code, • and which will require public notification of the violation. Further, a ., . public water supply system that does not filter may lose filtration . avoidance if there are more than two turbidity events during the previous twelve month period or five turbidity events in the last 120 month period , ~' Therefore, the City finds this potential treatment critically important to the ~r 4~ protection of our water supply and retention of filtration avoidance for thin t4' r

NYC-WTC 000137773