Erosion Control Using Wood Waste Materials

Abstract

The field experiments presented here investigated the required thickness of wood waste materials used as a mulch to protect a soil slope against erosion. Each of the materials was subjected to large-scale erosion control testing at a field site with a slope of 1 vertical to 2 horizontal. Fourteen test cells (5′ W × 30′ L each) were prepared with different wood waste treatments; nine contained erosion control mulch applications at thicknesses of 3/4 to 3 inch. Two cells were left untreated as reference cells and three other cells were untreated but contained erosion control structures including wood waste filter berm, geosynthetic silt fence and hay bale silt barrier. The erosion control performance of each cell treatment was evaluated for 11 storm events of varying rainfall magnitude and intensity. Calibrated tipper buckets were used to measure the runoff from each cell and collection buckets were used to sample runoff and determine the mass of sediment eroded from each cell. Total rainfall and intensity of each storm was measured with an electronic rain gauge. The results showed that 0.75 inches of wood waste material is sufficient to reduce the erosion to levels below commonly used treatments. Using thicker applications of wood waste did not reduce the erosion much below that obtained with 0.75 inches. This effect was demonstrated with three different wood waste materials. In addition, one of the wood wastes (paper mill wood waste) was used as a filter berm to control eroded soil particles. The behavior of this berm was compared to standard methods of controlling these particles such as hay bales and geosynthetic silt fence, and found superior. Laboratory tests are planned to quantify the properties of wood waste that produce good filtering action in berms.