Land Use and Land Cover Effects on Runoff Processes: Fire

Abstract

Fire dramatically alters hydrologic processes in many regions of the world. Individual fires reduce vegetation and change soil characteristics, sometimes producing dramatic runoff events in the years shortly after a fire. The greatest determinant of the effect of fire on runoff generation is the severity of the fire, which relates to the frequency of fires and other climatic and vegetation characteristics. Severe fires can produce hydrophobic soils or increase risk of soil surface sealing, reducing infiltration rates. Measurements of the spatial pattern of water repellent soils are useful for estimating potential runoff from postfire storms. The most severe events occur during convective storms, so the spatial extent of individual postfire floods is generally limited in extent. Recovery of water repellent soils is relatively rapid, with significant reductions occurring within a few years. Longer-term changes to hydrology are related to the reduced evapotranspiration caused by loss of vegetation biomass. In forests, changes to annual water balances may last decades.

Impacts of Forest Fires and Climate Variability on the Hydrology of an Alpine Medium Sized Catchment in the Canadian Rocky Mountains

“…Compared to the simple burned area map from ESRD Alberta [33], Landsat data deliver valuable information about the plant characteristics and changes of vital vegetation occurring with a fire event [46]. Most importantly, the RdNBR method delivers information about different grades of burn severity which are, according to Luce [39], the supreme determinants for the dimension of the impact of a wildfire on the hydrology of a watershed.…”

“…The decreased infiltration has an immense effect on post-fire runoff especially for extreme precipitation events during convective storms, when overland flow rises. The soils generally recover within a few years [39]. The long-term effects of forest fires on hydrology are caused by a reduction in evapotranspiration due to the loss of biomass, similar to those effects occurring after harvesting.…”

“…The changes in annual water budgets can last for decades in forested regions [39]. Severe fire events can reduce infiltration rates as a consequence of the generation of a hydrophobic soil layer caused by high temperatures or soil sealing forming crusts after a fire [10,39].…”

“…Interception of rain and snow is also reduced. During the winter the snow melt rates are higher due to reduced shading by canopy [39].…”

Utilization of Historical Maps in the Land Use Change Impact Studies: A Case Study from Myjava River Basin

“…Collecting, processing and analysing this data became a very active area of research that provided scientifically and practically relevant results in many disciplines such as agriculture, ecology, forestry or water management. In water management and hydrology the research is mainly focused on the effect of land use changes on runoff and erosion processes (see, e.g., Bruijnzeel, 2005;Burt and Slattery, 2005;Endreny, 2005;Goldman et al, 1986;He et al, 2013;Hlavčová et al, 2007;Li et al, 2013;Luce, 2005;Ray et al, 2010;Rončák and Hlavčová, 2014; as well as the dynamics of these changes over time (Butt et al, 2015;Lambin et al, 2003;RIKS BV, 2008;Verburg et al, 2002). A special category of studies analysing changes in land use over time deals with information from historical sources such as old maps, cadastres, land registers, and other historical documents.…”