Update of Soil and Nutrient Loss from Subwatersheds of Conesus Lake - 2001

Abstract

The State of Conesus Lake: Watershed Characterization Report (2001) identified areas that required additional data to evaluate the current state of the Conesus Lake watershed. A comprehensive update of nutrient and soil loss from all of the major subwatersheds from a study undertaken in 1990-91 (Makarewicz et al. 1991) was listed as a high priority. This study was designed to estimate discrete losses of total phosphorus and total suspended solids in eighteen subwatersheds during the calendar period April to December under both baseline and event conditions. Results of this study will be the ability to assess the change in nutrient loss rates for subwatershed during the past ten years and the prioritization of subwatersheds for further identification of point and nonpoint sources of pollution and their eventual remediation. The skewing of sampling protocol toward events (equal number of baseline and event samples, which doesn’t represent the proportion of event and baseline days in a calendar year) was done with the recognition that many of these streams run intermittently and a majority of their loadings to Conesus Lake occur during event periods (Makarewicz et al. 1991, Makarewicz and Lewis 1999 and 2000). In addition, this study will build upon and strengthen the data gathered in the past two years on the smaller stream and rivulets. Macrophyte beds consisting mainly of Eurasian milfoil exist at or near many of the creek mouths within the littoral zone of Conesus Lake (Fig. 1)(Bosch et al. 2001). These creek-associated beds are of interest because their presence appears to be associated with creeks that lose a large amount of nutrients and soils from their subwatersheds. Some suspected subwatersheds are candidates for a USDA grant to evaluate management plans that may reduce nutrient and soil loss.