Land Use in Flood-Prone Areas and Its Significance for Flood Risk Management—A Case Study of Alpine Regions in Austria

Abstract

Increasing flood damage has led to a rising importance of land use in flood risk management policies, commonly referred to as the spatial turn in flood risk management. This includes policies aiming at making space for rivers, which, in practice, lead to an increasing demand for land. Although research has been conducted on the variety of policies, the resulting land use conflicts in flood-prone areas have not been paid much attention to. This paper therefore analyses the current land use and its changes in Alpine flood-prone areas in Austria. The results show that space for rivers has been decreasing due to human activities (e.g., river straightening and channel narrowing) since the middle of the 19th century, and settlements have been expanding into flood-prone areas. Furthermore, the share of valuable agricultural land (which is important for food production) located in flood hazard zones is higher in more mountainous areas. Given the limited space for permanent settlement in Alpine regions, these land use changes exert pressure on the availability of land suitable for flood risk management. Therefore, making space for rivers as part of flood risk management policies faces considerable restrictions in Alpine areas.

Changes in the Natural Water Retention of mountainous landscapes since the 1820s in the Austrian Alps

“…Alpine areas of Austria have experienced strong LULCC since the mid of the 19 th century. Recent studies showed that these LULCC have resulted in an increased flood exposure and flood risk, especially in Alpine valley corridors (Hohensinner et al , 2021;Junger et al , 2022). Sustainable land use and properly managed LULCC can however be beneficial for water regulation (Vandecasteele et al , 2017).…”

“…The difference between the historical and present WRI maps reveals that LULCC negatively affected the water retention potential primarily in valley floors. This links the significant settlement developed in Alpine valleys leading to increased flood exposure (Hohensinner et al , 2021;Junger et al , 2022) with a decreasing capacity for water regulation. The altitudinal comparison of the WRI with the natural WRI, which does not consider the settlement area parameter in the calculation, shows that the reduction of the water retention capacity is significantly lower without settlements.…”

“…The decrease of WRI in the valley floors is strongly associated with the development of settlement areas and the truncation of wetland areas by 95 %. The strong settlement development led to an increase of settlement areas located within flood prone areas and therefore also increased flood exposure (Junger et al , 2022). Accordingly, large scale losses of fluvial corridors led to decreasing flood retention capacity (Hohensinner et al , 2021), somehow a lose-lose situation.…”

“…Therefore, land use and land development management are crucial tools for maintaining hydrological ecosystem services including water retention and flood control. Grüneis et al (2021), Hohensinner et al , (2021) and Junger et al (2022) investigated flood risk changes due to LULCC, thereby analysing flood exposure and focusing on Alpine valley corridors. In contrast, the present contribution examines how LULCCs since the mid of the 19 th century (Hohensinneret al , 2021) affected the hydrological ecosystem services of water regulation and flood control based on the Water Retention Index (WRI).…”

Habitatrestauration mit Ablaufdatum? Integration dynamischer Prozesse in der Sanierung von Fließgewässern

“…Aber nicht nur aus ökologischen Gründen wird heute darüber nachgedacht, Fließgewässern wieder mehr Raum zu geben. Auch aus schutzwasserwirtschaftlicher und damit auch raumplanerischer Sicht erscheint dieser Ansatz sinnvoll (Junger et al 2022). In diese Richtung weisen unter anderem die "Room for River Directive" in den Niederlanden und in Kanada sowie Analysen zur praktischen Umsetzung einer Strategie, um Flüssen in Deutschland mehr Raum zuzugestehen (Hartmann 2011;Rijke et al 2012;Warner et al 2012).…”