Sediment production from forest road surfaces

TLDR

Erosion on roads is a major source of fine‑grained sediment in streams draining logged basins of the Pacific Northwest. Runoff rates and sediment concentrations from ten road segments with varying traffic were monitored to produce sediment rating curves and unit hydrographs for different use levels and surface types, which were then combined with continuous rainfall records to estimate mean annual sediment yields per use level. A heavily used gravel road contributes 130 times more sediment than an abandoned road, while a paved road with only cut slopes and ditches yields less than 1 % of the sediment from a heavily used gravel road.

Abstract

Erosion on roads is an important source of fine‐grained sediment in streams draining logged basins of the Pacific Northwest. Runoff rates and sediment concentrations from 10 road segments subject to a variety of traffic levels were monitored to produce sediment rating curves and unit hydrographs for different use levels and types of surfaces. These relationships are combined with a continuous rainfall record to calculate mean annual sediment yields from road segments of each use level. A heavily used road segment in the field area contributes 130 times as much sediment as an abandoned road. A paved road segment, along which cut slopes and ditches are the only sources of sediment, yields less than 1% as much sediment as a heavily used road with a gravel surface.