Wildfires remove protective vegetation, produce ash with high content in potential pollutants, and enhance runoff processes, leaving the landscapes vulnerable to catastrophic flood, erosion and water contamination events. The resulting losses and costs of the actions taken to reduce risks to population and infrastructures, or to restore ecosystem functions following wildfires have increased dramatically in the last 30 years. For example, in the USA mitigation costs have increased from $6.3 M. in the 1970s to $188 M. in the 2000s (no data have been published for the EU).
Major advances have been made in the last decade to support land managers: (i) models to anticipate runoff and erosion events in the post-fire period, such as the Water Erosion Prediction Project model (WEPP, US Forest Service); and (ii) innovative hillslope stabilization treatments aimed at reducing runoff occurrence and erosion events.
Although widespread in the USA, the application of these advances is still in its infancy Europe due to the lack of region- and soil-specific calibration and effectiveness testing, leading in some cases to a risk to lives and resources in particularly vulnerable areas. Population and infrastructure in volcanic regions are usually extremely vulnerable to hydrological and erosional events due to their location in, or downstream of, fire-prone steep slopes, high population density, and the general instability of volcanic terrain. For example, in 2009 a severe erosion event occurred in a fire-affected area in volcanic terrain in La Palma (Canary Islands, Spain) that led to damages to infrastructure (€5 M.) and affected public safety during the first rainstorm after the fire. The lack of adapted models to predict runoff, erosion, and ash transport and knowledge on the effectiveness of post-fire mitigation treatments hinders the ability of managers to predict catastrophic events and protect human lives, infrastructure, and ecosystem services.
This project aimed to fill these knowledge and management gaps by using an innovative field, laboratory, and modelling approach and a carefully chosen implementation programme, involving global leaders in academia, industry and management. This successful collaboration resulted in (i) the validation and calibration of the WEPP model for the volcanic soils of the Canary Islands (Spain), (ii) the evaluation of the effectiveness of three alternative and innovative hillslope stabilization treatments for this terrain type, and (iii) the development of a model prototype to predict ash transport and contamination risk to water bodies.
