Application of a distributed process-based hydrologic model to estimate the effects of forest road density on stormflows in the southern Appalachians

Managed forests have historically been linked to watershed protection and flood mitigation. Research indicates that forests can potentially minimize peak flows during storm events, yet the relationship between forests and flooding is complex. Forest roads, usually found in managed systems, can potentially magnify the effects of forest harvesting on water yields. The distributed hydrology-soil-vegetation model was successfully calibrated at an hourly time step for a 760-ha watershed in the Blue Ridge Mountains of North Carolina. The impacts of forest road density were modeled using uniform input parameters but changing road densities. Road densities tested were 0.5, 1.0, 3.0, 4.3, 6.0, and 12.0 km km^-2. Results indicate that increases in road density increased average stormflow volume by as much as 17.5% when road densities increased from 0.5 to 4.3 km km^-2(P < 0.05). Overall, model simulations suggest that minimizing road density necessitated by the land use and appropriate forest road best management practices can be used to minimize impacts on stormflow.