Targeting Conservation Investments in Heterogeneous Landscapes: A distance function approach and application to watershed management

To achieve a given level of an environmental amenity at least cost, decision-makers must integrate information about spatially variable biophysical and economic conditions. Although the biophysical attributes that contribute to supplying an environmental amenity are often known, the way in which these attributes interact to produce the amenity is often unknown. Given the difficulty in converting multiple attributes into a unidimensional physical measure of an environmental amenity (e.g., habitat quality), analyses in the academic literature tend to use a single biophysical attribute as a proxy for the environmental amenity (e.g., species richness). A narrow focus on a single attribute, however, fails to consider the full range of biophysical attributes that are critical to the supply of an environmental amenity. Drawing on the production efficiency literature, we introduce an alternative conservation targeting approach that relies on distance functions to cost-efficiently allocate conservation funds across a spatially heterogeneous landscape. An approach based on distance functions has the advantage of not requiring a parametric specification of the amenity function (or cost function), but rather only requiring that the decision-maker identify important biophysical and economic attributes. We apply the distance-function approach empirically to an increasingly common, but little studied, conservation initiative: conservation contracting for water quality objectives. The contract portfolios derived from the distance-function application have many desirable properties, including intuitive appeal, robust performance across plausible parametric amenity measures, and the generation of ranking measures that can be easily used by field practitioners in complex decision-making environments that cannot be completely modeled. Working Paper # 2002-01

The Effects of Impervious Surfaces and Forests on Water Quality in a Southern Appalachian Headwater Catchment: A Geospatial Modeling Approach

The water quality of streams is impacted by the land cover types that occur within their watersheds and stream corridors. Research has indicated that impervious surfaces (roads, roofs, and parking lots) exert significant stress on stream system health by increasing storm runoff and transporting pollutants into streams. Forests, on the other hand, serve to protect water quality by slowing runoff, which allows rainfall to percolate into the ground, and absorbing pollutants. This thesis research examined the effects of impervious surfaces and forests on water quality in the headwaters of the New River in Watauga County. Results demonstrated that these effects are clearly identifiable and statistically significant. Limiting the amount of impervious surfaces that occur within 100 meters of streams and establishing 50 meter forested stream buffer zones could improve water quality and help preserve stream system health