Although erosion takes place naturally, the speed and amount of erosion can be increased by human activities, such as grazing, logging, or farming.
Roads produce nearly all management-derived surface erosion and sediment delivery to streams.
Adding drainage to roads can substantially reduce sediment delivery. Mass wasting is not a dominant erosional process in the project area but can be locally significant. Surface erosion occurs when water flows across a soil surface and fine particles are carried down the slope and into the stream. This mass movement of the soil is often triggered by too much water on a steep slope, which allows gravity to overcome the forces that would otherwise keep the soil on the slope. Excessive sediment can limit this part of salmonid habitat.