Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: July 15, 2011
Publication Date: September 18, 2011
Citation: Frankenberger, J.R., Dun, S., Flanagan, D.C., Wu, J.Q., Elliot, W.J. 2011. Development of a GIS interface for WEPP model application to Great Lakes forested watersheds [abstract]. In: D.C. Flanagan, J.C. Ascough II, and J.L. Nieber, editors. Proceedings of the International Symposium on Erosion and Landscape Evolution (ISELE). ISELE Paper No. 11139. American Society of Agricultural and Biological Engineers, September 18-21, 2011, Anchorage, AK. 711P0311cd. 2011 CD ROM. Technical Abstract: This presentation will highlight efforts on development of a new WEPP GIS interface, targeted toward application in forested regions bordering the Great Lakes. The key components and algorithms of the online GIS system will be outlined. The general procedures used to provide input to the WEPP model and to display model output will be demonstrated. The Water Erosion Prediction Project (WEPP) model is a computer program for soil erosion estimation, used at the scales of hillslopes to small watersheds. The model, written in FORTRAN, accepts text input files and writes output to text files allowing a general or specialized user interface to be created with other software. On the desktop the WEPP Windows interface is the primary software used to create WEPP input files and to display results. The WEPP Windows interface is written in Microsoft Visual C++ and is comprised of a front-end GUI that contains all the Windows specific code and a back-end module in C++ capable of running on other operating systems. In addition to the WEPP Windows interface other user interfaces for WEPP have been developed over the years. These include ArcGIS-based GeoWEPP, which can set up WEPP watershed simulations on a desktop, US Forest Service web-based WEPP interfaces customized for disturbed areas and forest roads, a general ARS web-based interface for hillslopes, and an online GIS interface for small watersheds. The new online WEPP GIS interface provides a seamless way for a user to zoom to any area of the US to set up a WEPP watershed simulation. The newest online GIS WEPP interface uses the OpenLayers and MapServer GIS software with base image data from Google. Server web pages are written using a combination of PHP and HTML, which connect to a server PostgreSQL database. In addition, custom programs written in C++ assist in preparing WEPP inputs and interpreting WEPP outputs. A user needs only a web browser to set up and run a WEPP online GIS simulation, as all data and programs reside on web servers. GIS data sources include USGS 30-m National Elevation Data, USGS Topographical maps, USGS Landuse and NRCS soil data. Daily climate inputs are generated from the long-term climate parameters of the nearest station using CLIGEN. Monthly climate parameters can be adjusted by using the PRISM gridded data to account for locations away from CLIGEN stations. The online GIS WEPP soil data for an area of interest can be retrieved using the NRCS Soil Data Access web services, which provide a way to query the NRCS soil database and return spatial data and tabular soil parameters. General USGS landuse classes are associated with detailed WEPP management inputs, which the user can adjust. Other GIS layers can be added to the map for reference. Interface components specific for forest applications of WEPP have been added to the new online GIS interface. These include the ability to adjust the default landuse or soil data for a subcatchment to represent conditions after a forest fire or timber harvest. Soil properties can also be customized to represent disturbed forest conditions. In addition, hydraulic measures (e.g., impoundments) and forest roads can be added for a more detailed assessment. Simulation projects developed online can be downloaded and run using the WEPP Windows interface, which provides the user the ability to further customize the WEPP inputs.