Forest Road Prism

The effectiveness of four road turn–out ditch treatments (vegetation, rip–rap, sediment fences, and settling basins) in reducing sediment export to the forest floor was evaluated. These four runoff control methods are commonly prescribed to control forest road runoff and sediments. The study utilized runoff samplers, runoff diversion walls, sediment filter bags, and erosion stakes to evaluate runoff concentration reductions through the treatments and sediment export downslope of the treatments. Settling basin, sediment fence, and vegetation treatments had no significant differences in runoff concentration reductions, which averaged more than 40%. The rip–rap was significantly less effective at reducing runoff concentration than were either the vegetation or sediment fence. The sediment basins were very effective during smaller storm events, but not during the largest storms, when they overflowed. The sediment basin exported the least amount of smaller–sized sediment that is likely to be delivered to stream systems.