Analysis of Climate Change’s Effect on Flood Risk. Case Study of Reinosa in the Ebro River Basin

Eduardo Lastrada,Guillermo Cobos,Francisco Javier Torrijo

doi:10.3390/w12041114

Abstract

Floods are one of the natural hazards that could be most affected by climate change, causing great economic damage and casualties in the world. On December 2019 in Reinosa (Cantabria, Spain), took place one of the worst floods in memory. Implementation of DIRECTIVE 2007/60/EC for the assessment and management of flood risks in Spain enabled the detection of this river basin with a potential significant flood risk via a preliminary flood risk assessment, and flood hazard and flood risk maps were developed. The main objective of this paper is to present a methodology to estimate climate change’s effects on flood hazard and flood risk, with Reinosa as the case study. This river basin is affected by the snow phenomenon, even more sensitive to climate change. Using different climate models, regarding a scenario of comparatively high greenhouse gas emissions (RCP8.5), with daily temperature and precipitation data from years 2007–2070, and comparing results in relative terms, flow rate and flood risk variation due to climate change are estimated. In the specific case of Reinosa, the MRI-CGCM3 model shows that climate change will cause a significant increase of potential affected inhabitants and economic damage due to flood risk. This evaluation enables us to define mitigation actions in terms of cost–benefit analysis and prioritize the ones that should be included in flood risk management plans.

Highlights

Floods are natural hazards that produce great material damage and human losses worldwide [1].The increasing population density and infrastructure on river banks contribute to increased floodplain vulnerability, which can result in severe social, economic and environmental damage [2].The fourth of the nine essential rules of flood risk management indicates that it should be taken into account that “The future will be different from the past
The technical document of the IPCC IV forecasts a probable increase in the frequency and intensity of precipitation episodes, as well as a decrease in average values in summer for mid-latitudes countries as Spain
The Fifth Assessment Report (AR5) of the IPCC (2013–14), points out that it is probable that the frequency or intensity of intense rainfall has increased in Europe, and in relation to future changes, that extreme precipitation events over most of the mid-latitude lands will most likely be more intense and more frequent [7]

Summary

Introduction

Floods are natural hazards that produce great material damage and human losses worldwide [1].The increasing population density and infrastructure on river banks contribute to increased floodplain vulnerability, which can result in severe social, economic and environmental damage [2].The fourth of the nine essential rules of flood risk management indicates that it should be taken into account that “The future will be different from the past. Climate and societal change as well as changes in the condition of structures can all profoundly influence flood risk” [3]. For all these reasons, it is essential to design methodologies that enable one to estimate flow regime variations and evaluate flood risk modification due to climate change. The Fifth Assessment Report (AR5) of the IPCC (2013–14), points out that it is probable that the frequency or intensity of intense rainfall has increased in Europe, and in relation to future changes, that extreme precipitation events over most of the mid-latitude lands will most likely be more intense and more frequent [7]. Climate change can specially affect those regions in which the snow phenomenon is relevant in hydrological behavior

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