Chain of custody record, Westchester County Lab, Nov 2001

NYC 9/11 Public Portal Document

LIMNOLOGY (EAST OF HUDSON) West Branch Reservoir - Full Survey Prepared by Keith Chin, EOH Limnology

A fijll survey of West Branch Reservoir was conducted on October 10, 2001. Sites sampled included Site 1, located in front of the dam; Site 2, located at Shaft 10 where water leaves the reservoir; Site 3, located at Shaft 9 where water enters the reservoir; and Site 4, located in the northeast basin separated from the main basin by a causeway. Samples were analyzed for a series of physical, chemical and microbiological parameters according to NYCRR Part 700; Memorandum of Agreement; NYC Rules and Regulations; and NYC system specific reservoir standards. The results of the survey are as follows: Currently all sites are isothermal with temperatures ranging between 15 °C and 16 °C. Turbidity levels were above the internal alert standard of 1.5 NTU at all sites except for Site 3. Color was above the secondary standard of 15 color units at all sites except for the top and bottom of Site 3 and the top of Site 4. Secchi disk measurements were 3.2 meters at Site 2, 4.5 meters at Site 3, and 2.5 meters at Site 4. Median dissolved oxygen (DO) concentrations measured between 7.7 and 8.9 mg-L’* at all sites. Total phytoplankton levels were below the DWQC internal standard of 2000 SAU mf’ at all sites. Individual genera counts exceeded the DWQC internal standard of 1000 SAU mf^ at the top of Site 4 (1300 SAU mf’, Melosira dominant). Total coliform levels were below the SWTR limit of 100 CFU- lOOmf’ at all locations. Fecal coliform exceeded the SWTR limit of 20 CFU- lOOmf’ at the bottom of Site 1 (24 CFU- 100ml ').

SUTTON PARK UPSTATE LABS KINGSTON LEFRAK M. Principe Ben Nesin Lab S. Schindler F. LaPorta D. Smith Croton Lab T. Tipa Grahamsville Lab Central Lab Katonah Lab Kensico Lab

NYC-WTC_000070925