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J.P. Nunes et al. 2010. Impacts of wildfires on catchment hydrology
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Impacts of wildfires on catchment hydrology: results from monitoring
and modeling studies in northwestern Iberia
João Pedro Nunes 1* , José Javier Cancelo 2 , María Ermitas Rial 1 , Maruxa Malvar 1 , Filipa
Tavares 3 , Diana Vieira 1 , Frederike Schumacher 3 , Francisco Díaz-Fierros 2 , António
Dinis Ferreira 4 , Celeste Coelho 1 & Jan Jacob Keizer 1
1
University of Aveiro, Portugal
2
University of Santiago de Compostela, Spain
3
Dresden University of Technology, Germany
4
Polytechnic Institute of Coimbra, Portugal
Abstract
Wildfires have significant impacts on vegetation cover and soil properties, which in turn can
lead to large increases in runoff, erosion and nutrient export from forested hillslopes. However,
the impacts of these changes at the catchment scale are still poorly understood, mostly due to
the difficulty of instrumenting burnt catchments with enough speed to capture hydrological
processes at the early stages of forest recovery. Hydrological modeling remains therefore an
important tool to assess wildfire impacts in ungauged catchments, but most existing models
cannot reproduce hydrological processes in burnt soils.
This work will present results from ongoing research projects in the northwestern Iberian
peninsula, including (i) multi-year runoff, erosion and soil properties monitoring in burnt and
unburnt hillslopes and micro-catchments (0.1 to 10 Km 2 ), providing insights into the local-scale
impacts of wildfires on hydrological processes; (ii) modeling approaches to simulate
hydrological processes in burnt areas at the plot and watershed scales.
Keywords: hydrological modeling, burnt forests, upscaling
1. Introduction
Forested watersheds in northwestern Iberia provide important ecosystem services for water
resources provisioning. According to the Millennium Ecosystem Assessment (Pereira et al.,
2004), these include the regulation of runoff (preventing flash floods) and maintenance of
downstream water quality. However, the planting of homogenous commercial forests has
significantly increased forest fire risk in the Iberian Peninsula (Puigdefábregas, 1998); climate
change is expected to increase the frequency and severity of these fires by enhancing the effect
of environmental drivers behind them (e.g. Carvalho et al., 2001). This could lead to a
disruption of ecosystem services during the post-fire window of disturbance (i.e. as forest
vegetation regrows), leading to an increase in e.g. the likelihood of flooding or a degradation of
water quality (Pereira et al., 2004). However, there is still a lack of knowledge on the effects of
wildfires on hydrological processes, especially at larger spatial and temporal scales (Shakesby
and Doerr, 2006).
* Corresponding author.
Email address: jpcn@ua.pt
Forest Landscapes and Global Change-New Frontiers in Management, Conservation and Restoration. Proceedings of the IUFRO Landscape Ecology
Working Group International Conference, September 21-27, 2010, Bragança, Portugal. J.C. Azevedo, M. Feliciano, J. Castro & M.A. Pinto (eds.)
2010, Instituto Politécnico de Bragança, Bragança, Portugal.