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Data Extent

Geomorphic Road Analysis and Inventory Package (GRAIP)

Roads have been shown to alter the hydrologic and geomorphic response of watersheds and can impact aquatic ecosystems and degrade water quality. The Geomorphic Road Analysis and Inventory Package (GRAIP) is designed to help land managers learn about the impacts of road systems on erosion and sediment delivery to streams. GRAIP couples analytical tools with an inventory process to build an approach to roads analysis that can be locally calibrated in a repeatable fashion and with minimal effort. The full scope of GRAIP includes methods to inventory roads and analyze the inventory for surface erosion, gully risk, landslide risk and stream crossing failure risks. Methods to measure road surface erosion from sample sites are also included.

GRAIP is a process and a set of tools for analyzing the impacts of roads on forested watersheds, and combines a road inventory with a powerful GIS analysis tool set to predict sediment production and delivery, mass wasting risk from gullies and landslides, stream diversion potential, culvert maintenance, and fish passage at stream crossings.

The road inventory protocol describes how to systematically field inventory a road system using GPS and automated data forms. Once downloaded, these data can be immediately run through a data quality checking and correction program. Quality checked data can then be analyzed in a program implemented in ArcGIS. The program produces maps of surface erosion, accumulated road sediment in streams, and contributing length by segment, which relates directly to slope stability and gullying risks. Other analyses relating to stream diversion potential, stream crossing failure, culvert maintenance needs, and fish passage are also provided with the program.

A more general prioritization tool that can be applied over a broader area without the cost for intensive field data is also available as GRAIP_Lite.

Release Date
Spatial / Geographical Coverage Area
POLYGON ((-124.95225392282 48.459344412943, -123.63389454782 48.342640982219, -123.10655079782 48.517595739566, -123.01866017282 49.096432175307, -112.99912892282 48.98119927124, -112.64756642282 44.654088846933, -114.75694142282 42.748111256816, -124.95225392282 42.424561320844, -124.07334767282 46.861214402111))
Spatial / Geographical Coverage Location
Western United States
USDA Forest Service
Data Dictionary
Contact Name
Parkes-Payne, Sharon
Contact Email
Public Access Level