This raster dataset has been created using the attribute field 'Value' from the 'Impervious Surface Area for Southeast Pennsylvania, 2000' data as originated by Toby Carlson, Penn State University (see metadata entitled 'pa2000isaa_se.htm'). The average of impervious surface was then calculated for the small watersheds (see metadata entitled 'smallsheds.xml'). Conservation Values were assigned based on the average impervious surface as follows: Avg. Impervious Surface Value 0-6 10 7-7 9 8-8 8 9-9 7 10-10 6 11-12 5 13-14 4 15-16 3 17-18 2 19-20 1 21-100 0 Conservation values were determined by experts gathered by Natural Lands Trust through SmartConservation. This data set is one of several that have been combined to create an overall aquatic resources conservation value raster for the expanded piedmont ecoregion. Therefore the values were determined as a relative rank, comparable in value only to the other input aquatic resources data. Conservation value ranges from 1 - 10 with 10 being the highest value.