Interactive Gis - Based Impervious Surface

Research has shown that impervious surfaces, a consequence of development, have a direct impact upon stream quality. Local planners and land-use officials need simple tools to help them determine the amount of impervious surface within watersheds and to assess impacts from future development. This paper describes an ArcView GISbased model being developed by the Northeast Regional Earth Science Applications Center that estimates imperviousness at the local watershed level. The model uses land-use land-cover data interpreted from multitemporal 1995 Landsat TM imagery and land-use land-cover-specific impervious surface coefficients derived from large-scale planimetric data from Connecticut towns that range from rural to urban. Currently, there are two mo des of operation. A user can evaluate all watersheds completely or partially within a town and generate a screen display that depicts estimates of stream quality based on existing land-use and land-cover conditions or a user can evaluate a single watershed. When assessing a single watershed there is an option to change existing forest and agricultural land to urban land uses to calculate future increases in impervious surface area and its impacts on water quality. The model is being developed as an educational tool that will be used by the Nonpoint Education for Municipal Officials (NEMO) Program at the University of Connecticut.