Forest roads represent the single greatest potential for severe, long term erosion and sedimentation from forestry activities. The nature of roads generally involves maintaining a “bare soil” condition on the road surface and periodic maintenance of both the surface and any associated ditches.
Permanent access roads are often accompanied by permanent drainage ditches or other drainage structures designed to transport stormwater. Serious road deterioration can result if ditch or drainage structure capacity is exceeded during storm events. This can lead to flooding of the road and surrounding area, scouring of the road and ditch surface, blowing out of roads and culverts, all of which may ultimately result in sediment delivery into streams or other waterbodies. To properly design, build, drain and maintain forest roads, the following BMPs are provided.
BMPs for Forest Roads
Road Planning
- Carefully plan the location and the desired drainage features before construction, using soil survey maps, topographic maps and aerial photographs - Plan construction activities for dry periods
- Minimize stream and wetland crossings. Roads will be less costly to build and maintain, equipment “down time” will be reduced and the water resource will be protected.
Road Construction
- Avoid construction operations during wet conditions - If possible, complete construction several months before heavy usage. This will reduce surface scour and decrease sediment transport.
- Balance cuts and fills to maximize use of local material and to maximize roadbed stability.
- To reduce both road costs and disturbed surface area, minimize the road width consistent with the anticipated type and amount of traffic.
- For fill road construction, keep road shoulders at a gentle slope to minimize erosion and accelerate revegetation.
- Stabilize road banks and critical road segments using mulch, seed and fertilizer, or other methods to keep the road from washing and to keep sediment out of streams (Appendix 6).
Road Drainage
- Drain road systems using culverts, cross ditches, turnouts, etc., to encourage long term stability, reduce maintenance, and protect water quality (Appendices 7, 8, and 9).
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