Flood Label for buildings – a tool for more flood-resilient cities

River floods are among the most expensive natural disasters in Europe. Traditional flood protection methods are not sufficient anymore. It is widely acknowledged in the scholarly debate and in practice of flood risk management that traditional flood protection measures such as dikes need to be complemented with measures to increase the resilience of cities. For cities to become flood-resilient, actions by land users (and homeowners) are required. Currently, land users insufficiently implement measures to mitigate flood-induced damages. Reasons for this include the lack of knowledge about potential measures and the benefits as well as lack of tailored information on flood risk. In this paper, a tool is discussed that addresses these two issues: the German Flood Label for buildings (Hochwasserpass). It is discussed how such a tool can create awareness by land users and how it can trigger the realization of precautionary damage mitigation measures. It will then be discussed how such a tool needs to be embedded in a strategic governance arrangement between land users, water authorities and insurance companies to ultimately achieve flood-resilient cities.


Introduction
Floods are among the most expensive natural disasters. ¼ PLOOLRQ LV WKH HVWLPDWHG GDPDJH RI WKH summer 2013 river floods in Central Europe. In 2002, the damage ZDV ¼ PLOOLRQ LQ D VLPLODU DUHD In 2013, 37 % of all damages from natural disasters were caused by inundations. Much of the damages occur at the individual household level (Munich Re, 2014a). The Intergovernmental Panel on Climate Change (IPCC) states ZLWK ³KLJK FRQILGHQFH´ that damages by river floods will substantially increase in Europe (IPCC, 2014). Other flood events caused by flash floods or rising groundwater levels are also expected to increase.
At the same time, the vulnerability of cities continues to increase as well (Loucks, Stedinger, Davis, & Stakhiv, 2008). Even in areas of the global North with sophisticated land-use planning and comprehensive water management, urban development still takes place in flood-prone areas, without adaptation (Hartmann, 2012;Petrow, Thieken, Kreibich, Merz, & Bahlburg, 2006).
It is widely acknowledged in scholarly debate as well as flood risk management practice, that traditional flood protection measures such as dikes need to be complemented with measures to increase the resilience of cities (Klijn, Samuels, & van Os, 2008), such as precautionary flood damage mitigation measures. The recent European Floods Directive recognizes the need to reduce vulnerabilities (Directive 2007/60/EC on the assessment and management of flood risks, 2007). But contemporary practices in flood protection are still mainly focused on technically-oriented flood defence (Hartmann & Juepner, 2014;Jüpner, 2005). The practice of flood risk management reveals that implementing precautionary flood damage mitigation measures is quite difficult (Hartmann, 2011b) and water management agencies often focus instead on technical measures, because this is more within their control (Klijn et al., 2008).
This leads to and increases the dike paradox² sometimes called the ³HVFDODWRU HIIHFW´ LQ IORRG SROLF\ (Saurí-Pujol, Roset-Pagès, Ribas-Palom, & Pujol-Caussa, 2001). This is when land users feel safe and protected behind dikes or other technical measures, and they accumulate (immobile) values in their houses without adapting to the flood risk (Tempels & Hartmann, 2014;Wagner, 2008). This phenomenon has also been denoted DV ³FOXPV\ IORRGSODLQ´ +DUWPDQQ D But since the flood risk is a product of both probability and potential damage, both variables must be reduced in order to reduce risk (Houghton, MacCarthy, & Metz, 2001;Patt & Jüpner, 2013).
The flood-resilient city is able to absorb negative consequences of such flooding (Begum, Stive, & Hall, 2007;Bruijn, 2005;Petrow et al., 2006)²in other words, flooding leaves minimal damage (Holling, 1996). One of the advantages of a flood-resilient city is that it not only responds to river floods or coastal storm surges, but also reduces impacts from flash floods, impounding water from the sewage system, or rising groundwater levels.
Cities are not meant to be inundated. So the floodresilient city requires adaptation. Existing approaches to resilient cities focus on public infrastructure at the city level (e.g. streets as discharge flumes, multifunctional  ( 2016) areas, evacuation routes, or non-structural measures) (Berke & Campanella, 2006), whereas major damages occur foremost on buildings on private land (Osberghaus, 2015). There is a wide range of flood damage mitigation measures for individual buildings, which can reduce damages by inundations. In summary, these have the potential to make cities more flood-resilient (Brombach et al., 2013). However, most of these measures need to be implemented by homeowners (e.g. implementing valves against backwater or swales to drain water) or require land users ¶ action (e.g. change of use of certain building levels) (Bubeck, Botzen, & Aerts, 2012).
In order to have a substantial effect on cities, these individual flood damage mitigation measures need to be realized on a city or at least the neighborhood level to avoid worsening the single individual situation (e.g. leading water to the neighbour). If land users would indeed realize such measures in a coherent area, flood risk management strategies could be developed in a much more efficient and effective way (Patt & Jüpner, 2013;Poussin, Botzen, & Aerts, 2014). (If not explicitly stated otherwise, throXJKRXW WKH UHPDLQLQJ SDSHU µODQG XVHUV ¶ LV used to refer to land users, land owners and homeowners). So, one of the key questions of resilient cities is: How can we get land users within a coherent area to realize precautionary flood damage mitigation measures on land and buildings?

The Flood Label
7KH )ORRG /DEHO µHochwasserpass ¶ LV D WRRO ZKLFK is designed to increase the preparation of individual households. It has been developed by the Flood Competence Centre in collaboration with the insurance industry (Scheibel & Johann, 2015). It will be conceptually elaborated in this contribution how such a Flood Label can be used for achieving the flood-resilient city. Therefore, a governance arrangement will be proposed and discussed. Methodologically, the paper mainly builds on literature studies and first-hand experiences with the Flood Label (pilot studies are pending throughout 2016/2017). x Communicate individual IORRG risk with land users.

The Flood Label in two steps
x Identify tailored measures for buildings.
x Strategically apply the tool in a coherent area. The remaining paper discusses these three challenges and derives conceptual ideas for what they mean for the development of a Flood Label for Buildings.