SUPERVISOR: Thomas ERTL

PROJECT ASSIGNED TO: Lena SIMPERLER

Stormwater management in urban areas has an influence on river water quality as well as quantity. Therefore, appropriate treatment of stormwater is important for the river ecology. In Austria a large proportion of the municipalities are already connected to drainage systems and wastewater treatment plants leading to a good treatment performance regarding effluent quality.

The prevailing infrastructure are sewer systems and wastewater treatment plants planned for specific boundary conditions with a design life of more than 50 years. The boundary conditions for stormwater management are however changing more rapidly. Various drivers for change including climate change and urbanization are leading to retrofitting within existing urban structures. They are further enhancing the need for interdisciplinary planning approaches to stormwater management with a bigger focus on spatial framework conditions. In addition a shift towards more integrated stormwater management is occurring promoting the implementation of nature-based solutions (NBS). Especially in densely built areas the availability and ownership of land can be a limiting factor for the adaptation of drainage systmes. An interdisciplinary approach to the adaptation of sewer systems is needed.

Different planning processes regarding stormwater management have been developed to tackle the challenge. Evaluation tools used in the planning processes are however often not considering the spatial framework conditions, which are especially important for the management of stromwater in existing urban structures and the implementation of NBS.

The aim of this thesis is therefore to explore which tools can be used to analyse the existing spatial framework conditions and how these can be utilized to make stormwater management more resilient to changing spatial framework conditions in the future through adapted planning processes.

The basis for the analysis are research projects covering different aspects of challenges in stormwater management regarding spatial framework conditions. One being the adaptation of existing drainage systems with an increase in aboveground measures for stormwater management. The second challenge is the runoff from periurban areas due to heavy rainfall and its influence on the drainage system.

Based on these examples pivotal spatial framework conditions for stormwater management will be defined and tools for analysing their influence will be investigated. The tools will besides other means incorporate hydrodynamic simulations and spatial analysis of different aspects. The applicability of the tools for different problems will be investigated and a better understanding of the influence of changing conditions on the existing infrastructure shall be gained.

Furthermore, the potential for taking those spatial framework conditions better into account in an adapted planning process of stormwater management will be analysed.