HEC-HMS Users Manual Watershed Physical Description Current: References: Watershed Physical Description PDF Download PDF Download page References: Watershed Physical Description. Current page All pages References: Watershed Physical Description Autodesk, Inc. 2005. "AutoCAD 2006 Customization Guidebook." San Rafael, CA.Barnes Jr., Harry H. 1967. "Roughness Characteristics of Natural Channels." U.S. Geological Survey, Denver, CO.Environmental Systems Research Institute, Inc. July 1998. "ESRI Shapefile Technical Description." Redlands, CA.U.S. Geological Survey. September 1999. "Standards for Digital Line Graphs: Part 2 Specifications." Department of the Interior, Washington, DC. ×