ABSTRACT
The current version of the Revised Universal Soil Loss Equation-Version 2 (RUSLE2) does not estimate concentrated flow erosion, which can be substantial in agricultural fields. The primary objective of this chapter is to describe our ongoing efforts using geographical information system (GIS) tools and highresolution topographic elevation data to develop a distributed version of RUSLE2 that can be linked with a process-based channel erosion model to account for
5.1 Introduction .................................................................................................... 70 5.2 Grid-Based RUSLE2 ...................................................................................... 71
5.2.1 Overland Flow Paths ........................................................................... 72 5.2.2 Channel Networks .............................................................................. 72 5.2.3 2D “Profiles” ....................................................................................... 73 5.2.4 Erosion Computations ......................................................................... 73 5.2.5 Enhancements to RUSLE2 ................................................................. 74
5.3 Materials and Methods ................................................................................... 74 5.3.1 Model Application to Watershed “W-11” in Iowa .............................. 74
5.4 Results ............................................................................................................. 76 5.5 Problems That Remain to Be Solved .............................................................. 78 5.6 Conclusions ..................................................................................................... 81 References ................................................................................................................ 82
concentrated flow erosion. This is being accomplished by modifying the RUSLE2 so that runoff can be estimated and local slope length can be determined based on accumulated runoff. This chapter provides (1) a detailed description of these proposed methodologies; (2) results from a case study in a research watershed located near Treynor, Iowa, demonstrating how these techniques can be used to assist conservation planning decisions; and (3) an example dataset and step-bystep procedure that will help practitioners apply RUSLE2 in 2D.
