A new design to evaluate erosion and sediment control
Water quality issues surrounding sediment movement related to forest operations are a focus in forest management. The forest road system is a primary area of concern related to sediment movement because roads are a component of most forest operations. Controlling sediment movement is a common objective in most forestry best management practices (BMPs). However, there is a lack of information documenting the effectiveness of prescribed practices in reducing sediment loads from forest road systems. This is primarily due to the complexity of assessing the effectiveness of erosion and sediment control, stormwater control, and BMPs in the forest setting. Consequently, little sediment transport and BMP effectiveness information or data are available. Monitoring designs for effective evaluations of erosion and sediment control practices are critical to further reductions in sediment contributed from forest roads. This paper presents general engineering design aspects involved in evaluating erosion control, sediment control, and BMPs on the forest landscape. The paper discusses considerations involved with the selection of monitoring equipment and structures based on design storm and costs. Statistical considerations in the selection of an experimental design to optimize data collection and increase the probability of statistically valid results are presented. In addition, an innovative study design (real world) and application to address sediment control BMP issues will be reported. This study was initiated on the Tallulah District of the Chattahoochee National Forest that aims to evaluate the effectiveness of three road sediment control treatments (alternative BMPs) settling basins, sediment basin with riser control, and hay bale barriers in filtering sediment laden storm runoff. The BMP effectiveness study design utilizes stormwater samplers, trapezoidal flumes, automated flow level devices, flow dividers, and runoff tipping buckets to evaluate sediment transport through sediment control treatments. This design has the potential to set standards for forest road sediment control evaluations.