Since January, 1967, bacterial analysis of raw water from Otsego Lake has been conducted by the NYS Department of Health nea r the intake of Cooperstown's water supply at the Mill Street pump station (Baldwin, 1975). The water is initially drawn from approximately 15 m in depth (upper hypolimnion) 300 m north of the entrance to the Susquehanna River.
Village records include sporadic data from 1927 to date (Table 39) (Peters, Unpbl.). Between January 1991, and December 1994, the highest reading was 23 MPN (Most Probable Number)/100 ml on 5/31/91. More than 110 analyses were conducted during that time period. Only 7 samples showed numbers greater than 2 MPN/100 ml. However, ephemeral periods of high turbidity (NTU's greater than 5) of raw water, which in other waters often are associated with high bacterial counts, have resulted in several "boil water" notices by the NYS Department of Health since 1991.
In 1985, Public Health Law #1100 was locally implemented to protect the potability of Otsego Lake water for the Village of Cooperstown. Land use regulations, the employment of an enforcement officer and the establishment of the Village of Cooperstown Otsego Lake Watershed Supervisory Committee, supplemented the legislation. Since that time, percolation tests to establish soil conditions suitable for sub-surface sanitary waste disposal systems are conducted concurrently with new construction throughout the watershed. Failing systems are inspected and brought up to code.
In recent years, data have been collected concerning the distribution and abundance of fecal indicators (total coli form, fecal coliform and fecal streptococcus) in Otsego Lake and its tributaries (Ehlers, 1989; LaBarre, 1990; Harman and Austin, 1990; Austin, 1991; Monie, 1991; Van Dusen, 1992; Iannuzzi, 1991a; b; Coffin and Bicker, 1993; Sohacki, Unpbl.; Albright, Unpbl.; Miller, 1996). Additionally, the upper Susquehanna River has been monitored (Neale et al., 1992,; Vatovec et al., 1993; Hahn, 1994; Hahn and Homburger, 1994; Miller, 1996). Areas with chronically high populations of bacteria have i ncluded the Susquehanna River where it leaves the lake, the mouths of Willow Brook and Hayden Creek entering the lake, Hayden Creek in the vicinity of Springfield Center, and the west shore of Otsego Lake in the vicinity of Six-mile Point.
The most intensive work was done by Iannuzzi (1991a; b) in 1988. Total coliform numbers ranged from zero to somewhat greater than 200 colonies/100 ml, with the highest counts typically recorded at the shoreline stations and TR1-C. Mid-lake counts at TR4-C a nd TR6-C remained below 50 colonies/100 ml throughout the year. Shoreline counts and those at TR1-C were sporadic during ice cover, then steadily increased on the average from near zero during spring turnover, to the highest counts recorded in August. Counts remained at near maximum levels through mid-October, then decreased to zero or near zero during fall turnover. Fecal coliform counts ranged from zero to greater than 100 colonies/100 ml.
The spatial and temporal patterns were nearly ident ical to those for total coliform for the yearly data set. Fecal streptococci counts ranged from zero to greater than 100 colonies/100 ml. However, counts remained at or near zero for most sites throughout the year. Significant counts were obtained only at TR7-C (the Cooperstown waterfront) and TR2-W (in front of the motels on the west side of the lake in the Town of Springfield). Furthermore, the only noticeably high counts were recorded at TR2-W, which corresponded to the summer maxima for total co liform and fecal coliform.
As a result of the above studies, sources of pollution have been ascertained for the Susquehanna River and Hayden Creek. An undiscovered source is assumed to be in the Six-mile Point area. Bacteria populations in Willow Brook appear to be derived from non-point sources associated with Village runoff and domestic waterfowl. Several of these sources have been eliminated, others are under consideration by watershed officials.