DEP Environmental Protection Invoices, 1999-2001

NYC 9/11 Public Portal Document 1U / FJUL ♦o;_4 DIU'- - _J VNOt b4/tl~

A. Limnological monitoring will be performed at sites 3.1, 4, 4.1, 4.2 and 5 on days 1, 2, 3, 5, 7 and 9 and then three times per week as proposed in the attachments to Mr. Hoffer's January 8, 2001 letter to Ms. Duke of NYSDEC. Any changes in alum and sodium hydroxide dose or treatment regime (e.g. increase in alum and sodium hydroxide dose) due to increases in turbidity should result in increased monitoring (i.e. revert to daily sampling until stable turbidity removals are achieved). The City must make every effort to sample these sites, regardless of ice cover conditions.

B. The sediment traps deployed at Sites 5, 4.2, 4.1 and 4 during the addition of alum and sodium hydroxide to the Catskill System must be collected every week.

C. Pathogen samples (Giardia spp. and Cryptosporidium spp.) must be collected daily at the two Kensico effluent keypoint locations (DEL 18 & CATLEFF) throughout the duration of the alum and sodium hydroxide application, unless a reduction is authorized by this Office;

5. keypoint and Limnological monitoring results are to be submitted to this Office as the data become available. Pathogen data are to be transmitted within one week from the sample date;

6. the City must demonstrate that every effort is being made to reduce unnecessary or excessive water use within the City's distribution system;

the City must accelerate the repair/remediation efforts currently underway in the Southern portion of the New Croton Aqueduct. Every possible effort should be made to expeditiously get the Croton system back on line;

8. the City must maximize the use of the Delaware and Croton systems during this alum and sodium hydroxide treatment event; and

9. the DEP must notify this office when the alum and sodium hydroxide operation is terminated and prepare and submit an After Action Report within 60 days of the end of the alum and sodium hydroxide operation.

Sincerely,

Michael E. Burke, P.E. Director Bureau of Public Water Supply Protection

NYC-WTC 000137778