Flood protection Living against or with nature
Extreme environmental events contribute to catastrophic damages in urbanized areas across the world. For politicians, architects, sociologists and geoscientists protecting people and cities has become a paramount task. In June 2016 the Lower Bavarian town of Simbach am Inn experienced long-lasting rainfall followed by an extreme flood, with similar events taking place in Baden-Württemberg and comparable to the 2013 floods in Passau and Deggendorf. Seven casualties and hundreds of millions of Euros in damages were reported in the Simbach area. An interview with the urbanist Mark Kammerbauer.
Mr Kammerbauer, how do these disasters take place?
Disasters occur when locations settled by people are confronted with floods and excessive rainfall. We attempt to prepare ourselves from such occasions by building protective structures such as levees. However, such forms of protection can be inadequate, or the related structures can fail, as it was the case in Deggendorf in 2013. In June 2016 in Simbach a drainage structure was clogged by debris due to the flooding. This contributed to the flood disaster further downstream. The sheer amount and velocity of the flood, exacerbated by the stream's embankments, led to destruction in the adjacent area and heavy damages to up to 500 houses.
Aside from the physical and economic consequences, your research focuses on the social impact of environmental disasters. What do the terms "vulnerability" and "resilience" mean?
Dealing with the social impact on residents is just as important as the rehabilitation of the built environment and post-disaster recovery. Both are highly interconnected. Often, seniors or individuals with limited capacities are hit hard by disaster. Poverty or lacking social networks also play important roles. The international research community uses the term "vulnerability" for such demographic aspects. In Germany, this circumstance has only received limited attention thus far. Vulnerable people are hit harder by disasters than others.
Simbach am Inn, July 2016 | Photo: Mark Kammerbauer
This is why the reduction of social vulnerability should be the goal of all involved disciplines. After disaster, early recovery measures can and should help people to return to their everyday lives, if possible. This also relates to architecture, urban planning and urban design: which structures need to be repaired and rebuilt, which parts of a city are affected? For the long-term recovery and future floodproofing of buildings and cities, measures related to construction and infrastructure should focus on the reduction of vulnerability in order to strengthen resilience. Flood risk management needs to address whether the degree of coverage of surfaces in urban environments can be reduced. Or, wether retention areas to enable runoff and drainage of floodwaters can be enlarged. These issues relate to the ability to resist and absorb shocks and can contribute to the preservation of existing structures while offering room for adaptation and improvement. Enhancing resilience should, therefore, be a shared planning goal.
Is complete disaster prevention possible?
It will be difficult to prevent disasters from occurring at all, unless we withdraw completely from all areas subject to risk. Nevertheless, we can reduce the impact of flood disasters. In order to do so, we need to revisit land use plans and building codes, alter them and adapt the related means of construction as required.
Which strategies exist to make buildings flood proof?
Floodproofing can be distinguished according to the concepts of dry proofing or wet proofing. The first approach aims at "shutting out" environmental impacts on buildings by making them, quite literally, "flood proof". Wet proofing is an approach that accepts the fact that buildings can flood and supports preparation based on particular materials and construction methods that allow for easy cleaning and acceptable repairs. Against this background, the question on floodproofing approaches almost becomes a philosophical one: do we intend to live "against" nature, or "with" it?
We also shouldn't forget historic construction methods. In the past, people had less advanced technological means to deal with environmental circumstances. Despite this fact, places such as Passau have been inhabited for centuries. Floods occurred here repeatedly throughout history, and ground floor areas of buildings located along the river banks were traditionally used as storage spaces. Historic farmhouses within the region feature raised ground floors made of masonry brick and with stone tile floors. Bedrooms are located along the upper floors consisting of timber construction.
How can the government help after disaster?
The government helped uninsured homeowners to recover and rebuild houses impacted by the 2013 floods in Bavaria. Only 30 percent of homeowners have flood insurance here. This is why recovery and reconstruction after disaster becomes a societal and political challenge and obligation.
Official documents, most notably the "Hochwasserfibel" (flood primer), are available to the public and feature information on disaster prevention and preparedness and how to reduce the impact of disaster. Such measures need to relate to the local and urban context and the surrounding landscape. Resilience can be created and fostered if actors from the political sphere, from architecture, urban planning, environmental management, civil protection and hydraulic engineering achieve consensus on land use planning and urban design. They also need to be aware of the existing capacity of citizens to prepare for, cope with, respond to and recover from disasters.
Photo: Andreas Graf Mark Kammerbauer is an urbanist and has researched environmental disaster across the globe with a focus on innovative planning and design strategies in disaster management and prevention. He holds degrees in architecture (TU München) and urban studies (Bauhaus University Weimar). In 2012 he was awarded a doctorate (Bauhaus University Weimar) for his research on rebuilding in New Orleans after Hurricane Katrina. His practice and research activity led him from Germany to the USA, the Netherlands, Australia and Sweden. He currently represents the Department "Theory of Architecture and Design" at the Faculty of Architecture at the Nuremberg Institute of Technology and is a postdoctoral guest researcher at the Lund University Centre for Sustainability Studies.