Sensitivity and Stability of the Iowa Daily Erosion Project 2 to Landscape Variability and Rainfall Intensity.

Abstract: The release of the Iowa Daily Erosion Project (IDEP) 2.0 model has made more comprehensive and dynamic estimates of sediment delivery, soil erosion, and hill slope runoff available for agricultural areas across Iowa. The integration of highly spatial and temporally resolute precipitation and climate data, spatially variable soil properties from current SSURGO information, remotely sensed crop rotation and residue management data, and increased spatial resolution of runoff and erosion estimates (elucidated from approximately 200,000 complex, 3-meter LiDAR elevation modeled hillslopes statewide) affords the opportunity to test model components that influence output stability of field-scale erosion event estimates. Discussion of the methods used to test the proper number of flowpath estimates within a watershed to obtain output stability of this WEPP-based model--as well as the appropriate effective length of those flowpaths randomly selected from the flow network generated per HUC 12 will be key points of the presentation. Impacts of these variables on model robustness will be discussed, with respect to outputs across plausible landscape and climatic ranges. Understanding these areas of sensitivity is paramount as work begins to expand the use of the existing technology into surrounding Midwestern states.