Water-related disasters : An overview of landslides and floods in Sweden

Sammanfattning: Current research shows that water-related disasters are the most common natural disaster worldwide and these disasters are increasing in numbers. Water-related disasters cause negative consequences through damage to infrastructure and human health.  This thesis aims to provide an overview of the water-related disasters, floods, and landslides in Sweden by displaying the spatial distribution. Furthermore, the purpose is to analyze the consequences of occurred water-related disasters. By answering the following research questions:  How has landslides and floods been spatially distributed over time in Sweden?  How severe has the consequences of floods and landslides been in Sweden?  To answer these research questions a data study was conducted in ArcGIS and Excel to analyze the spatial distribution and the consequences of landslides and floods. The result shows that the three counties in Sweden with the highest number of affected areas by floods are: Västerbotten, Västernorrland and Örebro. These counties constitute 36% of the affected areas. These affected areas have occurred periodically with an increase since 1970. A detailed study over the years 2011–2017 showed that most floods in Sweden lead to consequences with a small extent and limited damages.  Furthermore, the counties Västra Götaland, Västernorrland and Värmland had the highest number of occurred landslides. In total, 83.7% of all landslides have occurred within these three counties. This means that the distribution of floods is more evenly distributed between different counties compared to landslides. Within these counties, the areas that have had notable high numbers of landslides are Ångermanälven, Norsälven, Klarälven and the areas nearby Göta älv. Overall, it has been most common that landslides have an extent in the range between 1000–10000 m2 and that an extent over 100000 m2 are rare.