Detailed Analysis of Soil Erosion, Runoff, and Sedimentation in Farm Fields Using a Spatial Application of the WEPP Model

The Water Erosion Prediction Project (WEPP) model applies processes for water infiltration, soil water percolation, surface runoff, evapotranspiration, raindrop and shear stress soil detachment, sediment transport and deposition, plant growth, residue management and decomposition, and irrigation in simulations to assess the impact of cropping system management on soil and water resources. Extensive use of WEPP on agricultural land usually involves defining a hillslope representing an entire farm field, often for the most erosive soil in the field, good enough for planning purposes. These assessments do not provide a detailed view of soil detachment and flow of water and sediment within the field, thus not providing sufficient information to support precise design, placement, and application of conservation practices. The WEPP hillslope and watershed model, deployed as a web model service and integrated with Catena-GIS and the Cloud Services Integration Platform (CSIP), simulates soil erosion, runoff, and sediment transport along all flowpaths within the farm field. A CSIP service leverages TauDEM, 10-meter DEM, and clipping to create three delineation input layers: sub-watersheds, stream networks, and all flowpaths in the fields of a farm. Other CSIP services fetch parameters from common domain data sources to create soil and climate input layers. Users define the management of each field using CSIP services to fetch data from a common cropping system domain database to create the management input layer and crop rotation object to be used by the model. The WEPP model simulates each flowpath, iterating through each cell to the edge of the field. Simulations run in parallel to reduce total simulation time. Output from the model aggregates and renders to a variety of reports, maps, and graphs.