Incorporating Wetland Knowledge into Road Developments


Wetlands in the boreal forest can be classified as bogs, fens, swamps, marshes, and shallow open water according to their soils (organic vs. mineral), water chemistry, water flow, water table, and vegetation communities. The ability to classify wetlands and understand differences in ecology and hydrology of different wetland classes will help resource road planners and operators make decisions on where and how to build roads. Linear developments, such as roads, through wetlands may impede wetland hydrology causing surface and subsurface water to pond in upslope locations. Over time, these changes lead to tree loss upstream due to prolonged flooding, and divergent upstream and downstream vegetation communities. Building roads through wetlands also presents unique and often costly construction, maintenance, and safety challenges. Using DUC’s enhanced wetland classification (EWC), wetlands can be grouped according to their flow characteristics into stagnant, moving – slow lateral, moving – seasonally fluctuating, and inundated/flooded. In 2011 DUC received an SFI grant to work in partnership with LP Building Products, Weyerhaeuser, and FPInnovations, to develop and test log corduroy designs for crossing stagnant, moving – slow lateral, and moving – seasonally fluctuating wetlands. Monitoring results indicated that crossings did not impede water flow and 3 years post-installation the crossings as built were working well. DUC believes that understanding wetland type and flow characteristics can inform long term and seasonal road crossing planning and construction techniques, and provide guidance for road decommissioning and reclamation/restoration. We believe that by working together, we can achieve our common goals of maintaining wetland hydrology, maintaining waterfowl and other wetland-dependent wildlife habitats, improving road performance, reducing road maintenance costs, improving road safety, and reducing road decommissioning /reclamation costs.