APPLICATION OF REMOTE-SENSING AND GEOGRAPHIC INFORMATION-SYSTEMS TO THE DELINEATION AND ANALYSIS OF RIPARIAN BUFFER ZONES

Non-point source pollution has a significant impact on the quality of water resources. Studies have revealed that agricultural activities ar e often major contributors to non-point source pollution of aquatic en vironments. A common means of reducing the threat of non-point source pollution is through the establishment of riparian Vegetation strips ( or buffers) along those areas of stream channels that would be most su sceptible to the threat. Remote sensing and geographic information sys tems (GIS) offer a means by which 'critical' areas can be identified, so that subsequent action toward the establishment of riparian zones c an be taken. This research focuses on the development and analysis of riparian buffer zones for a portion of the Iowa River basin. Landsat T hematic Mapper (TM) data were used to characterize the land cover for the study area. An updated hydrology data layer was developed by integ rating the United States Geological Survey (USGS) Digital Line Graph ( DLG) data base with the TM-derived classification of surface water bod ies. Spatial distance search tools were applied to develop the buffer zones around all surface hydrologic features. The buffer zones were in tegrated with the remotely sensed classification data to identify 'cri tical' areas for the establishment of riparian vegetation strips. Resu lts indicated that while most of the main channel of the Iowa River wa s protected by natural vegetation, more than 44% (or 1008 ha) of the a rea along its tributaries lack any protective cover from non-point sou rce pollution. As these 'critical' areas are adjacent to agricultural fields it is important that water resources management strategies focu s on the establishment of riparian zones in order to minimize the impa ct of non-point source pollution. (C) 1997 Elsevier Science B.V.