1a.Objectives (from AD-416)
1. Define end-user requirements for the GIS-based RUSLE2 interface and establish evaluation criteria for the final product.
2. Establish clear objectives and guidelines for use and development of the tool based on input from key agency partners.
3. Identify and evaluate existing methodologies for using high-resolution DEMs to calculate slope length and steepness, as well as determine the most appropriate aggregation of soil loss calculations across a field landscape.
4. Develop a working prototype of a GIS-based RUSLE2 template.
5. Optimize the current RUSLE2 application to handle multiple calculations.
6. Provide demonstrations for GIS-based RUSLE2 template to SWCDs statewide.
7. Provide training and support for statewide use of the GIS-based RUSLE2 template.
1b.Approach (from AD-416)
Develop a summary report of end-user requirements and agency objectives based on stakeholder meetings and interviews. Prepare a list of final evaluation criteria for the GIS-based RUSLE2 template. Prepare a report on most appropriate methodology for using DEMs to interact with RUSLE2 and most appropriate application of RUSLE2 soil loss calculation across a field landscape. Document functional requirements for a GIS-based tool for statewide application. Evaluate slope length and steepness algorithms for applying LiDAR-derived DEMs to RUSLE2 model. Prepare a beta version of GIS-based RUSLE2 for stakeholder evaluation and obtain feedback on the proposed tool. Proivde trainings for beta users on operation of GIS-based RUSLE2 template and develop a written survey tool for stakeholder evaluation as a precursor to a summary report of stakeholder evaluation results. Prepare an enhanced GIS-based RUSLE2 template based on end-user experiences and requirements.
This agreement supports the objectives of the parent project and focuses on the development of a Geographic Information System (GIS)-based platform for Revised Universal Soil Loss Equation, version 2 (RUSLE2). The goal is to develop a tool for use at the county level by conservation planners to estimate erosion using a GIS-based platform. Incorporation of digital elevation maps (DEM’s) with soil maps as layers in a GIS platform from which RUSLE2 can be used on any field or portion of a landscape was defined as the first step in developing this type of approach. The initial efforts were directed toward defining the end-user requirements for the GIS-based RUSLE2 interface and establishing evaluation criteria for the final product. These were then coupled with the goal to identify and evaluate existing methodologies for using high-resolution DEMs to calculate slope length and steepness, as well as determine the most appropriate aggregation of soil loss calculations across a field landscape. These activities have focused on determining proof of concept for two proposed methodologies for determining flow path routing and slope length and steepness from the LiDAR-derived digital elevation models (DEM). One approach is to use a “representative hillslope” method and that has been replaced by cell-based flow pattern approach because this latter approach explicitly identifies the locations of the highest erosion areas within a field or soil polygon. These efforts have been completed and incorporated into the GIS level approach for the erosion models. This methodology shows promise as a robust tool for erosion assessment at the field-scale using the digital data obtained in the state of Iowa. There are monthly exchanges about the progress of the project and to discuss alternative approaches to increase the value of the user model.