Use of Log Mill Residuals as a Geotechnical Amendment to Mitigate Slope Erosion

Erosion of surficial soils, whether topsoil or fill, is a significant problem. Geotechnical aspects of soil erosion from wind and water have been mitigated with a variety of covers and treatments over the last 100 years. While some methods have shown to be more successful than others, significant limitations to widespread application are trucking costs for the massive volumes of material needed to treat large areas of erosion susceptible soils in the time before vegetation can take hold and serve as long-term erosion mitigation. A particularly attractive, low-cost, and readily available material in wooded areas with active logging are the materials in the pits and piles at sawmills and log mills. While the bulk of the sawdust is captured for economic benefit, the residuals are often pushed into pits and piles where they slowly compost. The residuals contain soil, rock, bark, leaves, needles, gravels, sawdust, and other minor organic wastes from the mill operations. To validate the use of these residuals for erosion mitigation, a study of both wind and water erodibility of these residuals was performed using wind tunnel, rainfall simulator, and laminar flume. Their compatibility with revegetation was also experimentally studied by growth of a clover cover crop. Experimental findings show that log mill residuals tested herein outperformed saw dust, sand, wood chips, compost, and several other conventional erosion mitigations covers in all experiments, including revegetation.