page_title: WEPP
section_title: Recent improvement
hierarchical_section_title: WEPP / Recent improvement
caption_attribution_description: English: Screen capture of one of the WEPP (Water Erosion Prediction Project) web-based interfaces for simple hillslope profile simulations
context_page_description: The Water Erosion Prediction Project Model is a physically based erosion simulation model built on the fundamentals of hydrology, plant science, hydraulics, and erosion mechanics. The model was developed by an interagency team of scientists to replace the Universal Soil Loss Equation and has been widely used in the United States and the world. WEPP requires four inputs, i.e., climate, topography, soil, and management; and provides various types of outputs, including water balance, soil detachment and deposition at points along the slope, sediment delivery, and vegetation growth. The WEPP model has been improved continuously since its public delivery in 1995, and is applicable for a variety of areas.
context_section_description: Over the last decade, researchers have made significant improvements to the WEPP model. These include improved algorithms to simulate the effect of hydraulic structures and impoundments on runoff and sediment delivery, the addition of Penman-Monteith ET algorithms, subsurface converging lateral flow to represent variable source area runoff, improved canopy biomass routines for forested applications, and the incorporation of an alternative, energy-balance-based winter hydrologic routine. A number of modern graphical user interface programs have also been created, to assist in easier application of WEPP. The main interface for the model is a standalone Windows application (downloadable via: http://www.ars.usda.gov/Research/docs.htm?docid=10621), that allows a user to simulate hillslope profiles and small watersheds and have full control over all model inputs (Figure 1). Additionally, web-based interfaces allow very easy and rapid use of the model while accessing existing soil, climate, and management databases (Figure 2).
  A number of geospatial interfaces to WEPP (example in Figure 3) are also available:
  GeoWEPP – an ArcView or ArcGIS extension that runs in conjunction with the WEPP Windows interface
  On-line web-based GIS interface to WEPP using the open source MapServer GIS program
  Iowa Daily Erosion Project
  NetMap
caption: Figure 2. Screen capture of one of the WEPP web-based interfaces for simple hillslope profile simulations. Inputs for and results from a 30-year model run are shown.
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