Hydrologic and Erosion Models to Assess Land Use and Management Practices Affecting Soil Erosion

Abstract

We developed a new, coupled, hydrologic-erosion model and a targeted field data-collection program to quantify hillslope soil erosion rates and sediment yield in semiarid regions. While the methodology has a wide range of actual and potential applications, we use military training activities as an example. The methodology is applied at the Yakima Training Center (YTC) in south central Washington, USA where most erosion and transport occurs during extreme events of short duration, often associated with rapid rain-induced snowmelt on frozen soil. The distributed hydrologic and soil erosion modeling system is used to simulate continuous water balance and soil thermal state throughout all seasons of the year. We estimated surface runoff and sediment yield for relatively undisturbed areas as well as from roads, firebreaks, and vehicle tracks associated with training activities at the study site. Field data were collected on over 100 hillslope profile transects across the YTC to parameterize, test, and evaluate the linked modeling system. We successfully validated the modeling system against several databases, upland sediment delivery to stream networks, and measured sediment yield from 12 sedimentation ponds within the YTC. The simulation results are superior to those from a currently used model, which help to illustrate applicability of the presented erosion prediction technology.