Flooding and soil erosion are two of the hazardous consequences of wildfires, and are of particular concern in the wildland/urban interface. This study examines the effectiveness of post-fire rehabilitation measures to reduce soil losses after the wildfires of 2003 in the Southern Interior of British Columbia, Canada. Bark mulch, straw mulch, needle cast and grass seeding are the treatments being studied. Sediment yield off hillslope plots is measured with the use of silt fences and related to rain events. The results after two seasons of monitoring indicate that, at all sites, the bark mulch, needle cast and straw mulch are effective in reducing soil losses. Seeding alone did not reduce erosion relative to the untreated plots. The sediment yields in the second year after fire were markedly lower than in the first year after fire, making the treatment differences less important and less clear. Fire-induced water repellency has been noted as one of the primary contributory factors that lead to hydrologic responses in watersheds. Repellency was measured using the Water Drop Penetration Time. Rainfall provides the energy to drive erosion, and this variable is measured by means of automatic recording gauges at each site. Understanding effective surface treatments to decrease soil losses will assist future planners in appropriate rehabilitative measures to limit soil erosion and subsequent debris flow processes in urban interfaces.
David F Scott.
Scott, David F., Jordan, Peter; Dobson, D.; Curran, Mike P.; Brookes, S.; Turner, K.; Grainger, W.; Geist, Kelli. 2006. Evaluation of fire site rehabilitation methods in terms of controlling erosion and sedimentation. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2006MR171