Publication describes costs, effectiveness of upgrades in forestry best management practices for stream crossings

Forest roads are often necessary for permanent or temporary access for forestry operations. Following passage of the Federal Water Pollution Control Act of 1972, state forestry agencies developed forestry best management practices (BMPs) specifically designed to minimize erosion and sediment associated with forest operations with major emphases on forest roads, skid trails, and stream crossings.

Although a large body of research has documented effectiveness of forestry BMPs, some authors have recommended additional research regarding sediment delivery from forest roads having different levels of BMPs.

Recently, scientists with Virginia Tech and the University of Canterbury (New Zealand) published a study that evaluated potential sediment production and solutions for stream crossings in the Piedmont region. Although the research was conducted in Virginia, the authors believe their findings have potential application in other geographical areas and land uses.

The research was supported by NCASI, the USDA National Institute of Food and Agriculture, the Virginia Department of Forestry. The Virginia Tech Department of Forest Resources and Environmental Conservation provided support for the study.

The abstract for the paper follows.

“Forestry Best Management Practices (BMPs) are used for protection of water quality at forest stream crossings, yet effects and costs for gradients of BMPs are not well documented. We evaluated forty-two truck road and skid trail stream crossings using three surrogates of BMP adequacy: (1) potential erosion rates for stream crossing approaches; (2) adequacy of stream crossing BMPs; and (3) overall BMP rating (BMP_, BMP-standard, and BMP+). Subsequently, BMP upgrades were recommended for enhancing BMP_ or BMP-standard stream crossings. Costs for BMP upgrades were estimated using an existing road and skid trail cost method. The majority of truck road stream crossings were culverts, while skid trail stream crossings were primarily portable bridges. Potential erosion estimates, BMP audit scores, and BMP ratings all indicated that skid crossings have lower BMP implementation than truck road crossings. BMP improvements commonly identified for skid trail and truck crossings included addition of cover and water control structures. Improved BMPs at skid trail crossings were less expensive than those at truck road crossings. Current BMP guidelines provide economical and effective techniques for reducing erosion, and BMP upgrades have the potential to reduce erosion rates to similar levels found in undisturbed forests.”

Reference 

Nolan, L., W.M. Aust, S.M. Barrett, M.C. Bolding, K. Brown, and K. McGuire. 2015. Estimating costs and effectiveness of upgrades in forestry best management practices for stream crossings. Water 7:6946–6966. http://dx.doi.org/10.3390/w7126668