NITRATE LOADING IN THE SENECA LAKE WATERSHED

The Seneca Lake Watershed provides an ideal natural hydrogeochemical laboratory to study the source and impact of non-point source pollutants. The 29 subwatersheds and drainages (adjacent first order streams) drain a variety of surface areas (from a few to over 100 km²), landuse (agricultural, forested and lesser amounts of urban land), bedrock (Paleozoic carbonates, shales and coarser silicate-rich clastic rocks), soils and other features. This project investigated the source and fate of nitrates in the watershed.

Weekly water samples were collected from May through August of 2001 and analyzed for Nitrate (ppm, N) and other common hydrochemical parameters (pH, alkalinity, hardness, conductivity, etc. by appropriate field meters and field titration kits) from the terminus of seven subwatershed that represent the array of available surface areas, landuse and bedrock in the basin. Samples were also collected at discrete sites along two streams to locate point sources. This information was supplemented by the hydrogeochemical database from the watershed over the past 5 years.

The results indicate that streams that drain agricultural land reveal the largest Nitrate concentrations (a few ppm up to 5 ppm), and a wastewater treatment facility provides a point source of nitrates to Big Stream. Hog farms are not the source of Nitrates as feared by the local communities, however the current number of hog farms are few in numbers and have been operating for only a few years. Nitrate inputs are modulated by biological uptake both in the stream and in the lake (lake concentrations typically range from 0.1 to 0.5 ppm).