Title: Reducing Sediment Production from Forest Roads during Wet-Weather Use.

Forest roads produce fine sediment with traffic during wet weather. If the forest road is connected to a stream it can be a source of turbidity and fine sediment that may be detrimental to aquatic organisms especially salmonids. The goal of this work was to investigate turbid runoff during wet-weather use from the pavement of forest roads that were designed to reduce sediment production. This research explored the opportunity costs associated with upgrading forest roads for environmental performance, determined a method to design an unbound aggregate pavement to reduce sediment production, and tested alternatives for road pavements that were designed specifically to minimize turbid runoff during wet weather hauling. The opportunity costs associated with restricted timber hauling and harvesting are potentially a resource that could be made available to improve aggregate road surfaces to minimize hauling restrictions during wet-weather. In this study the opportunity costs were 1.7 to 15 percent of the total net revenue for McDonald-Dunn Research Forest. A method of design for the pavement structure for unbound aggregate roads was developed. This “reduced stress ” design method designs against subgrade mixing by reducing stresses on th