As a Ph.D. student at the University of Washington, my research focuses on the erosion of forest roads in western Washington.
Erosion of high-traffic forest roads (i.e., mainline logging roads) is a large source of sediment in nearby streams. The fine-grained sediment generated by and transported from forest roads can adversely affect water quality and aquatic resources in logging-adjacent watersheds. Because of this, a project has been designed to help efficiently and effectively mitigate this sediment generation and transport from high-traffic, near-stream (HTNS) road segments. The project design includes the collection of extensive field data in western Washington, as well as the development of a theoretically-based model. This project is a collaborative effort among members of the Washington Department of Natural Resources (WADNR), Catchment Aquatic Ecology (CAE), Rayonier, the United States Forest Service (USFS), and the Watershed Dynamics Research Group at the University of Washington. The project consists of three main parts: the Major Experiment; the Parameterization Experiments; and the Modeling.
The Major Experiment
The Major Experiment is designed to measure annual sediment load and quantify how forest road best management practices (BMP) that are put in place affect that sediment load. We will have 80 experimental sites—40 sites in each of two lithologies. Each site consists of an 80 meter segment of road partitioned off by steel troughs and cross-drain culverts and is equipped with a sediment tub, a tipping bucket, and a suspended solids tank. Four pilot sites were installed in November 2018, and data collection at those sites is ongoing. The remaining 76 sites will be installed in May/June 2019.
The Parameterization Experiments
The Parameterization Experiments are designed to help answer six critical questions posed in our study design that are not necessarily answerable by the Major Experiment alone. We have six Parameterization Experiments planned: Ditch Line Hydraulics; Sediment Trap Efficiency; Cost Versus Maintenance Survey; Road Micro-Topography Evolution; Short-Time-Scale Interactions; and GRAIP/WARSEM Delivery Analyses. The Road Micro-Topography Evolution and Sediment Trap Efficiency Parameterization Experiments are both in progress.
The Modeling component of this project is designed to create a model to accurately represent the sediment yield from HTNS roads, as well as the effects that select BMP have on that sediment yield. The model will be developed using Landlab, a Python-based Earth surface processes modeling toolkit. Work on the model is currently underway.