Introduction
In 1998, the EPA cited Vermont as having 196 impaired waters. The Mad River, located in central Vermont, is one such impaired aquatic ecosystem due to the presence of fecal pathogens. Fecal pathogens are present in livestock manure that is deposited on agricultural fields by the animals themselves or by farmers when spread as a fertilizer. Runoff from these fields is thought to be a significant contributor of pathogens to the Mad River. One management practice for reducing contaminated runoff is the establishment of riparian buffer zones.
Whether it is spread as a fertilizer or deposited by farm animals, manure can enter streams from field runoff and lead to unacceptable fecal pathogen levels.
In general, the way to reduce NPS pollution from agricultural land is to incorporate some type of Best Management Practice (BMP). Riparian buffers (both riparian forested buffers and vegetative filter strips) are an extremely valuable BMP. Riparian buffers have proved effective in decreasing nonpoint source pollution (Correll, 1997; Lowrance et al., 1997a; Lowrance, 1997b; Lowrance et al., 1985) and are considered essential to protecting water quality (USDA, 1991). It is estimated that riparian buffers are able to prevent up to 80% to 95% of farm runoff from reaching aquatic systems (Dickey and Vanderholm, 1981; Glickman, 1998). To enhance water quality in the Mad River watershed, the United States Department of Agriculture (USDA) Natural Resource Conservation Service (NRCS) in conjunction with other federal, state, local, and volunteer organizations, has embarked on a program of providing financial incentives to local farmers to encourage the establishment of vegetative filter strips and riparian forested buffer zones (USDA, 1999).
Our research employs geospatial technology to improve the method by which NRCS identifies candidate riparian buffer areas. Geographic Information Systems (GIS) can integrate data such as land cover, hydrology, topography, and soils in order to identify the optimum locations for the establishment of riparian buffers. In order to effectively prioritize the agricultural fields needing riparian buffers we utilized the Revised Universal Soil Loss Equation (RUSLE).
We are conducting our research in a 5km x 20km area of the Mad River watershed. This study site includes the majority of the agricultural land in the Mad River valley. The Mad River houses some of Vermont's finest swimming holes.
3D perspective of the study area created by draping an IKONOS satellite image (© Space Imaging) over a digital elevation model. Land use/land cover and locational map of the study area.