GRAIP provides predictions about the amount and specific locations of road surface sediment that enters the stream channels, observations and risk predictions of road related gullies and landslides, stream crossing failure risks, and the condition of existing drainage and other road infrastructure. These outputs can be used to quantify existing risks, and to locate, prioritize, and monitor road maintenance, obliteration, and other types of treatments.
The field portion of the GRAIP process is a comprehensive GPS road inventory that includes observations of how and where water flows along each road segment and at each location where water leaves the road, road and infrastructure conditions including vegetation on the road, and whether road sediment is delivered to the stream network. These observations are imported into ArcGIS as shapefiles and combined with a DEM and derived hydrological rasters. The GRAIP toolbar/toolbox in ArcGIS then models the road surface sediment production and delivery to streams, risks of mass wasting (gullies and landslides), and risks of stream crossings becoming occluded. Results from the GRAIP model can be combined with the other field observations of existing road related gully and landslide volume and stream delivery, stream crossing conditions, fill erosion volume and stream delivery, and other drainage and road surface infrastructure condition problems.
It is not mandatory to have a high level of GIS or GPS training to begin working with GRAIP, but it is important to have a basic familiarity with ArcGIS and to be willing to learn. If your GIS skills are minimal it will help to take a basic GIS review course online or to have assistance from a local GIS specialist to get you started. We are willing to help people with basic GIS skills to learn the process and we periodically offer training in the use of GRAIP. The GPS equipment and inventory procedure are fairly intuitive and most students are functional after three days of training.
GRAIP depends on having precise location information about where water leaves the road and if that water is reaching the channel network via a surface flow path. Few people collect these data as part of routine road inventories so it has been hard to utilize this data in GRAIP. It is theoretically possible to make this work with the right data.
GRAIP has been used at a variety of scales from small road treatment projects to 5th code HUCS. The scale that is chosen depends on the goals being pursued. Many users have used GRAIP as a way of prioritizing where to focus restoration and road improvement work in basins with known sediment and aquatic habitat issues. GRAIP can show you where sediment-related problems are most severe within a larger area, and it can be used to show the effect of treatments to those sites.
There are a variety of tools that have been developed to predict the impacts of roads on the environment.
GRAIP_Lite uses DEMs, already existing road GIS layers with surfacing type information, and a small field calibration dataset to determine 6th code subwatershed scale road sediment production and delivery. Road layers are broken into GRAIP-style segments. Production is calculated in the usual GRAIP way, and delivery is based on the flow distance from the road to the stream and the calibrated probability of delivery at that distance. GRAIP_Lite is good at narrowing a large potential project area to the smaller watersheds with the most sediment problems.
WEPP a physically based model that predicts water and sediment movement on hillslopes and roads. There are a variety of formulations and interfaces for the basic WEPP model that can simplify its use for various purposes.
WEPP Road is a web based tool for estimating sediment production from a road segment given the input parameters of road length, road slope, road width, surfacing type, soil texture, road prism configuration and traffic loading. Climate files are provided that are used to simulate and drive the runoff and sediment predictions. Sediment delivery estimates can be predicted based on user inputs about the conditions below the road drain point. The inputs are soil texture, slope gradient, and flow path length. WEPP Roads is useful for quickly estimating the magnitude of sediment production from average road configurations and calculating the benefits of road improvements. It is not a spatially explicit model for road sediment so it may not capture the watershed scale effects of the road network.
The R1/R4 model including Boised, NezSed and other related models have been used by the Forest Service in the Rocky Mountain region to predict sediment production from roads, harvest units and burned areas. The road component of the model uses disturbed area, road slope, road age, erosion control mechanisms and road usage to calculate sediment production. Sediment delivery is estimated by assigning a delivery ratio to the land types on which the road is constructed.
SEDMODL2 is a model for predicting sediment production and delivery from forest roads developed by Boise Cascade and NCASI. The model works in GIS environment and like the R1/R4 methods it uses a linear combination of road factors to predict sediment production. Sediment delivery is based on road and stream proximity. Detailed information on drain point location is not mandatory, but is supported in later versions of the model.
Fish Xing is a tool kit for predicting fish passage through stream crossing features. This is a powerful tool that depends on a detailed survey of stream crossing and channels to predict the hydraulic conditions that will occur. These predictions are compared to the capabilities of a host of aquatic species to predict if and when the crossing may be a barrier to passage. The fish passage criteria used in GRAIP are based on a simplified set of assumptions from the literature and should be considered a first approximation indicating if further scrutiny is warranted. If FishXing or other fish passage surveys have been completed they can be used in place of the calculations made by GRAIP.
Though GRAIP and GRAIP_Lite share some elements, the two models are not equivalent. GRAIP is used to inventory and analyze forest roads at a fine road-segment scale, and utilizes an intensive field inventory to accomplish this. GRAIP results are spatially explicit within a few meters and can be used to locate, prioritize, analyze, and monitor specific road treatments. Because GRAIP is so comprehensive, the time investment often prohibits its application it on a scale wider than a 5th code watershed at a time.
GRAIP_Lite uses the same principles as GRAIP to determine broad-scale road surface sediment risks over a much wider area very quickly, and is used as a tool to determine where the largest problems likely occur on a 6th code subwatershed scale. Further work such as a full GRAIP inventory can then be applied in order to find the specific locations within the subwatershed that have problems that should be addressed. There is a minimal field component (to gather a calibration dataset), but most of the modeling uses existing datasets and can be completed in the office.
GRAIP is a comprehensive field-based road-related erosion modeling tool, incorporating not only road surface fine sediment production and delivery, but also observations and modeling related to mass wasting, stream crossing risks, and drainage infrastructure problems. GRAIP excels at helping managers prioritize and support BMP and restoration decisions. The GIS based output is location-specific, simplifies the assimilation of the information by managers, and facilitates its use in prioritization decisions. Model outputs can be easily displayed in the form of maps showing areas of high sediment delivery to channels and the road segments and drainage features that lead to the elevated risk. GRAIP methods are well-documented in peer-reviewed publications and technical reports. GRAIP uses field observations to determine the flow paths of water on roads and where water and sediment actually leave the road and connect to stream channels. GRAIP is able to use locally developed erosion rates to predict sediment production and delivery on a local and a watershed basis.
We suggest that you start in your areas of critical concern. In Oregon, Washington, and Idaho we are focused on roads impacting aquatic habitat for endangered fish species. We have worked on watersheds that are on the 303(d) list due to elevated fine sediment input. Other regions have concerns about road related landslides and gullies, post-fire effects and restoration, or decommissioning un-needed roads. GRAIP_Lite can help determine which watersheds in a larger area are likely to be most impacted by road surface fine sediment.
If you are going to try using GRAIP on a project-scale to model the change in sediment delivery before and after a treatment is applied, choose a project that has a sizeable road/stream interaction. A small timber sale on a ridge top location with 0.6 miles of temporary road may not show a substantial sediment impact in GRAIP if the roads do not approach the channel. GRAIP is good at finding sediment sources to reduce as the road and channel network become more proximally connected.
Pathfinder Office v.3 or later TerraSync v.4 or later ArcGIS 9 (an ArcGIS 10 version of GRAIP is currently being programmed and tested, and is expected to be released in 2016) TauDEM 4 SINMAP 2 GRAIP
For the most part, the field equipment is similar to many other field endeavors (measuring tapes, stadia rod, flag tape, etc.). The piece of equipment that may be more difficult to obtain is a GPS unit that can run TerraSync. Look at our updated list of equipment for a complete list of the necessary field equipment.
We hold trainings at the Research Lab in Boise, ID about once a year. To see the latest information on the next available training, go to the Training Opportunities page, or contact Tom Black at firstname.lastname@example.org.
The main difference is that GRAIP 1.0.10 was not compatible with ArcGIS 10, and so required the user to install the outdated ArcGIS 9 on their system. GRAIP 2 is compatible with ArcGIS 10. Additionally, GRAIP 2 runs as an ArcToolbox, whereas GRAIP 1.0.10 ran as a toolbar in ArcMap. Finally, GRAIP 2 uses up-to-date hydrological modeling and raster formats.
If the goal is to assess the road geomorphic impacts on a 6th code HUC for a management project it is recommended that the inventory progress in a systematic fashion through the road system, to maximize efficiency and minimize gaps or duplication. The system works most smoothly if the inventory is conducted from the stream bottoms towards the ridges.
The road inventory data can be collected from a variety of platforms as long as a GPS device can be used and fine-scale road and hillslope observations can be made. The most time-efficient way to collect data is from a vehicle, though that is not always possible. It is often necessary to cover closed roads and otherwise undriveable roads by foot, bicycle, or ATV.
We do not recommend editing the data dictionary without first discussing the implications with us. We have found that the GRAIP model is sensitive to very minor changes in the data dictionary, like adding or removing a space between characters. It is crucial that the data dictionary and the GRAIP model version be synchronized. Feel free to contact us to be sure that you have the latest versions available.
Past field projects have progressed at an average rate of about two miles per day per crew, with a range of less than one mile to ten miles. Variation depends on the work schedule, commute distance, local GPS reception, road type and amount of complication, and degree of topographic dissection.
There are a few ways to obtain a base erosion rate for GRAIP. The most accurate way is to install road sediment measuring plots in or near the area of interest that get weighed yearly for three to six years (see Black and Luce, 2013). If this has already been done at a nearby location with a similar geology type, then you may be able to use that base erosion rate. You may be able to use another erosion model to come up with a rate for your area, given soils, precipitation, etc. The default base erosion rate of 79 kg/m/yr comes from sediment plots at Low Pass in western Oregon in the late 1990’s.
The rule of thumb has been one to two days of pre-processing and data editing for every week of data collection per crew. Your results may vary depending on satellite reception quality (affects how much line editing must be done), rate of data collection, and number of data entry errors. It may be a good idea to pre-process the data frequently enough to find any problems while the crew is still working in the local area. There may be places that should be revisited to confirm drainage information or fill in data gaps. Running the model on pre-processed data generally takes under half a day if everything goes well, though analysis will take longer depending on what type of results you are looking for.
For questions about processes and errors during the computer modeling and analysis phase, see the Office manual or contact us. For questions about the field data collection phase, see the Field manual.
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