DEP Environmental Protection Invoices, 1999-2001

NYC 9/11 Public Portal Document 1/09/01 TUE 17:25 FAX yi4 255 3042 NYS DEC 2001

Post-i" Fax Note 7671 pals i/9 Ol pagoest , 3 TO „ fy Fpm H eo.Dep'.. 1Co.. 1 Pnono# J Prone. New York State Department of Environme Division of Environmental Permits, Region 3 razr—lt0/ ) _G ) ra:x J 21 South Putt Corners Road, New Paltz, New Yor Phone: (845) 256-3000 • FAX: (845) 255-3042 John P. Cahill Website: wvww.dec.state.ny.us Commissioner

January 9, 2001

Mark Hoffer, General Counsel Bureau of Legal Affairs New York City Department of Environmental Protection 59-17 Junction Boulevard Corona, New York 11368

RE: Emergency SPINES Permit for Addition of Alum and Sodium Hydroxide to the Catskill and Delaware Aqueduct Systems Towns of Mount Pleasant, North Castle and Harrison, Westchester County DEC PennitNo. 3-9903-00023/00006

EMERGENCY AUTHORTZATION

Dear Mr. Hoffer:

Based on your letter of January 8, 2001 (including proposed monitoring protocols), the NYS Department of Environmental Conservation (DEC) has determined that an emergency exists, as defined in Section 70- 0105.6 of the Environmental Conservation Law (ECL). Pursuant to Section 70-0116 of the ECL and 6 NYCRR Part 621.12, DEC makes the following findings:

Turbidity levels in the Asholcan Reservoir have increased as a result of severe wet weather precipitation events, particularly an event that occurred on December 16-17, 2000. These natural wet weather occurrences have in turn caused increased turbidity in the Kensico Reservoir. The Lower Effluent Chamber at the Kensico Reservoir is the first and only point of disinfection for the Catskill water supply, which serves as the potable water supply for millions of New Yorkers.

2. The Federal Surface Water Treatment Rule (SWTR) and the New York State Department of Health Sanitary Code provide that for an unfiltered surface water system, the raw water turbidity immediately prior to the first or only point of disinfection cannot exceed 5 nephelometric units (NTU). 40 C.F.R. § 141.71(c)(2)(i); 10 NYCRR § 5-1.30(c)(2). The turbidity requirement in both the SWTR and the New York State Sanitary code is a key provision intended to protect against the adverse health effect of exposure to pathogens in drinking water. Excess turbidity hampers disinfection by providing a shelter for pathogens by reducing their exposure to attack by disinfectants.

The New York State Sanitary Code defines a public health hazard as "an existing or imminent condition which can be responsible for or cause illness, injury, or death and for which immediate corrective or remedial action is required." 10 NYCRR § 5-1.1(ar). Disinfection which is

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