Data Sharing
The data that support the findings of this study are available from the
corresponding author upon reasonable request.
Abstract: Post-fire managers throughout the world use
predictive models to estimate potential erosion risks to aid in
evaluating downstream impacts of increased runoff and erosion, and to
target critical areas within a fire for applying mitigation practices.
Erosion prediction can be complicated by forest road networks. Using GIS
technology and a soil erosion model, this study evaluated the effect of
roads on erosion and sediment yield following a wildfire, and whether
the predictive models were providing reasonable results. The GeoWEPP
model was used to simulate onsite erosion and offsite sediment delivery
before and after fire disturbance. A 2-m resolution DEM was used as the
terrain layer. Erosion rates in excess of 4 Mg ha-1yr-1 were predicted mainly from the moderate and high
severity burn areas. Roads influenced both flow path and sub-catchment
delineations, affecting the spatial distribution of sediment detachment
and transport. Through that influence, roads tended to reduce estimated
erosion on slopes below the roads, but road fillslopes and steep
channels were areas of significant increases in erosion risks. Measured
deposition amounts along roads and in sediment basins were similar to
predicted amounts. The results confirm that road prisms, culverts and
road ditches greatly influence sedimentation processes after wildfire,
and they present opportunities to detain eroded sediments before they
reach downstream water bodies.
Additional Keywords: Soil Erosion; Watershed; Wildfire; Forest
Roads; WEPP Modeling