Reactivation of river corridors as an element of Blue Green Infrastructure (BGI), using Nature-based Solutions (NbS), for urban flood risk resilience in Dresden, Germany

Abstract

This thesis examines the reactivation of river corridors as a crucial element of Blue-Green Infrastructure (BGI) through the implementation of Nature-based Solutions (NbS) to improve urban flood risk resilience in Dresden, Germany. Dresden, located on the banks of the Elbe River, has faced significant flooding events, particularly in 2002, 2013, and 2016, highlighting the pressing need for efficient flood management strategies. Conventional grey infrastructure solutions, although initially successful, have been inadequate in dealing with the rising frequency and intensity of floods caused by climate change and urbanisation.

This study examines the possibility of reactivating river corridors to enhance flood resistance by employing integrated BGI and NbS strategies. The study centres on the Altelbarm region, an essential location for fasilating flood water flow and retaining water in the Elbe floodplain. This region is known for its varied land uses and significant difficulties in managing floods. The proposed interventions seek to reduce flood risks by reactivating natural watercourses and improving the floodplain's ability to handle flood runoff. These measures also aim to primarily provide hydrological, ecological, and social advantages.

The thesis utilises a qualitative methodology, which involves conducting a thorough examination of existing literature, analysing documents, conducting semi-structured interviews with different stakeholders, and making observations in the field. The examination of successful urban river corridor projects in Munich, Leipzig, and Singapore offers useful knowledge about the most effective methods and helps in evaluating the practicality of similar initiatives in Dresden.

The key findings emphasise the diverse advantages of BGI and NbS, including efficient management of stormwater, enhanced biodiversity, and providing recreational opportunities. This research highlights the significance of involving stakeholders, receiving regulatory support, and incorporating comprehensive urban planning in order to effectively execute these solutions. Nevertheless, the study also highlights the presence of obstacles such as limitations on land usage, regulatory hurdles, and the requirement for significant initial capital.

The feasibility study for the Altelbarm area recommends implementing targeted technical, hydrological, ecological, and social measures to improve flood resilience. These measures encompass the reactivation of original floodplain areas, the establishment of vegetated areas along riverbanks, and the incorporation of recreational areas that are compatible with flood mitigation. The study also highlights the importance of continuous monitoring, flexible management, and coordination with wider development, environmental, and natural conservation laws and policies.

In conclusion, the utilisation of BGI and NbS provides a viable and efficient approach for managing urban flood risks in Dresden by reactivating river corridors. The research offers technical and policy-level suggestions that can assist the city in designing and executing flood mitigation measures that can be scaled to other areas. These findings enhance the overall discussion on sustainable urban development and climate resilience, providing an example for other cities dealing with similar challenges.