Effects of wildfire on catchment runoff response: a modelling approach to detect changes in snow-dominated forested catchments

摘要

Wildfire is an important disturbance affecting hydrological processes through alterationnof vegetation cover and soil characteristics. The effects of fire on hydrological systemsnat the catchment scale are not well known, largely because site specific data from bothnbefore and after wildfire are rare. In this study a modelling approach was employed fornchange detection analyses of one such dataset to quantify effects of wildfire on catchmentnhydrology. Data from the Entiat Experimental Forest (Washington State, US) were used,na conceptual runoff model was applied for pre- and post-fire periods and changes werenanalyzed in three different ways: reconstruction of runoff series, comparison of modelnparameters and comparison of simulations using parameter sets calibrated to the twondifferent periods. On average, observed post-fire peak flows were 120% higher than thosenmodelled based on pre-fire conditions. For the post-fire period, parameter values for thensnow routine indicated deeper snow packs and earlier and more rapid snowmelt.nThe net effect of the changes in all parameters was largely increased post-fire peak flows.nOverall, the analyses show that change detection modelling provides a viable alternativento the paired-watershed approach for analyzing wildfire disturbance effects on runoffndynamics and supports discussions on changes in hydrological processes.