An important first step in managing forest roads for improved water quality and aquatic habitat is the performance of an inventory. The Geomorphic Roads Analysis and Inventory Package (GRAIP) was developed as a tool for making a comprehensive inventory and analysis of the effects of forest roads on watersheds. This manual describes the data analysis and process of a GRAIP road inventory study using GRAIP v. 1.0.8 and the field data dictionary INVENT 5.0.
GRAIP uses field data collected with a GPS and a specific data dictionary that is imported into ArcGIS as shapefiles. The data are corrected and then run through the GRAIP toolbar, which also uses inputs from TauDEM (for stream network delineation) and SINMAP (for landslide risk). GRAIP estimates the quantity of sediment generated for each road segment by modifying a base erosion rate with road slope, segment length, flow path vegetation, and road surface type. The sediment at each drain point is routed to the stream network based on field observations of delivery, and output as accumulated sediment in the entire network, direct sediment for each stream segment, and specific sediment per unit contributing area. Observations of delivery at each drainage feature can also be used to calculate road-stream hydrologic connectivity. GRAIP calculates landslide risk associated with additional water from road network drainage, and gully risk using the locations of mapped gullies with the road length draining to each gully and the slope of the hillslope below each gully. Stream blocking risk is calculated using the width and entrance angle of each channel compared to the crossing culvert width and angle. This document describes each of these steps in sufficient detail that an ArcGIS user with basic skills will be able to perform the analysis. The GRAIP road inventory and model work together to provide a flexible tool box to quantify the impacts of roads on watersheds and aquatic systems.
Related website: http://www.fs.fed.us/GRAIP/index.shtml
GRAIP Manual - Volume 2 - Office Procedures - 1.0.9 ADDENDUM (2014): This update to the office manual is necessary for use with the latest version of the GRAIP software, 1.0.9. Use it alongside the full office manual. If you are a new user, it is a good idea to skim the office manual and then the addendum so that you know which parts of the office manual are replaced by the addendum. Some procedures are different in 1.0.9.