Table 2. Base data layers included in the Trout Stream GIS database. Data type Source Purpose 30-m Digital elevation model (DEM), Georgia US Geological Survey Used to determine elevation and basin area of stream segments 1 : 24 000 hydrography, Georgia US Geological Survey Provided stream locations on the landscape and used to determine stream order 1998 Land cover of Georgia (30-m resolution Landsat satellite imagery) Natural Resource Spatial Analysis Laboratory (NARSAL), Institute of Ecology, University of Georgia Used to determine percent riparian and catchment forest cover conditions Georgia Conservation Lands and Georgia Department of Natural Resources Natural Resource Spatial Analysis Laboratory (NARSAL), Institute of Ecology, University of Georgia Used to identify trout streams on private vs. public lands Rules and Regulations for Water Quality Control Chapter 391-3-6, revised August 2000 Georgia Environmental Protection Division Used with hydrography layer to identify designated trout streams