Spatial simulation of forest road effects on hydrology and soil erosion after a wildfire

Abstract

Post‐fire catchment and water utility 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 novel GIS technology and soil erosion modelling, this study evaluated the effect of roads on surface runoff, erosion and sediment yields following a wildfire and determined that 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 using a 2‐m resolution DEM as the terrain layer. Erosion rates in excess of 4 Mg ha−1 year−1 were predicted mainly from steep moderate and high severity burn areas. Roads influenced surface runoff flow path distributions and sub‐catchment delineations, affecting the spatial distribution of sediment detachment and transport. Roads tended to reduce estimated erosion on slopes below the roads but increases in erosion rates were estimated for road fillslopes. Estimated deposition amounts on roads and in sediment basins were similar to measured amounts. The results confirm that road prisms, culverts and road ditches influence sedimentation processes after wildfire, and they present opportunities to detain eroded sediments.

A Multi-Model Multi-Scale Approach to Estimate the Impact of the 2007 Large-Scale Forest Fires in Peloponnese, Greece

“…Although no wide consensus has been established with regard to the questions posed in this work, we believe that there is a favorable perspective for this, which is justified by the recent intensification of related research efforts worldwide (e.g., [69][70][71][72], to mention but a few.) Additionally, one should not lose sight of the fact that many anthropogenic influences act simultaneously (e.g., forest fires, deforestation, large-scale hydraulic works) and affect the same hydrological variables by: (i) altering the rate of evaporation, (ii) modifying the velocity and amount of overland flow, (iii) altering the amount of infiltration into the ground, and (iv) affecting the amount of intercepted water [73].…”

Evaluating Basin-Scale Forest Adaptation Scenarios: Wildfire, Streamflow, Biomass, and Economic Recovery Synergies and Trade-Offs

“…Joint benefits to the fire and hydrology Primary topics were better realized with MaxBiomass and IdealWater treatments, providing evidence supporting the contributions of mechanical treatments in actively managed forests to multi-resource benefit strategies. However, inclusion of these treatments must consider restrictions on application in wilderness and roadless areas, as well as the potential negative impacts of harvesting practices on terrestrial and riparian ecosystem processes from road building and maintenance, and harvest operations (Forman et al, 2003;Cao et al, 2021).…”

Evaluating pathways to social and ecological landscape resilience

“…A team of researchers evaluated effects of treatments to remove small trees on water quantity (Harpold et al 2020, Harpold and Rajagopal 2020, Krogh et al 2020, and their findings identified using leaf area index as a key indicator for the DST. For water quality, a recent study (Cao et al 2021) determined that the Water Erosion Prediction Project (WEPP) model (USDA-ARS 2020), which was used in our analysis, performed well in simulating the actual sediment loads from the Emerald Fire. Meanwhile, additional field and modeling research within LTW found that mastication and prescribed burning were effective in reducing fuel loading while avoiding soil erosion, and that WEPP predictions were especially robust when erosion potential was high (Barnes and Harrison 1982, Harrison 2012, Harrison et al 2016.…”