Evaluation of flood hazard maps in print and web mapping services as information tools in flood risk communication

Abstract

Abstract. Flood risk communication with the general public and the population at risk is getting increasingly important for flood risk management, especially as a precautionary measure. This is also underlined by the EU Flood Directive. The flood related authorities therefore have to develop adjusted information tools which meet the demands of different user groups. This article presents the formative evaluation of flood hazard maps and web mapping services according to the specific requirements and needs of the general public using the dynamic-transactional approach as a theoretical framework. The evaluation was done by a mixture of different methods; an analysis of existing tools, a creative workshop with experts and laymen and an online survey.The currently existing flood hazard maps or web mapping services or web GIS still lack a good balance between simplicity and complexity with adequate readability and usability for the public. Well designed and associative maps (e.g. using blue colours for water depths) which can be compared with past local flood events and which can create empathy in viewers, can help to raise awareness, to heighten the activity and knowledge level or can lead to further information seeking. Concerning web mapping services, a linkage between general flood information like flood extents of different scenarios and corresponding water depths and real time information like gauge levels is an important demand by users. Gauge levels of these scenarios are easier to understand than the scientifically correct return periods or annualities. The recently developed Bavarian web mapping service tries to integrate these requirements.

Linking social capacities and risk communication in Europe: a gap between theory and practice?

“…Specifically, we identified a disconnect between the recommendations for long-term, coordinated communication strategies that can be found in the research literature (e.g. Hagemeier-Klose and Wagner 2009;O'Neill 2004) and the isolated nature of the many promising practices and tools that are currently being trialled in Europe. Based on our review of both literature and practice, we have recommended that if risk preparedness is to be improved, a longer-term, multiple-tool strategy is needed that builds up emotional and mental resources and knowledge on how to act, which keeps memory alive and combines episodic, regular and permanent tools.…”

Recommendations for the user-specific enhancement of flood maps

“…also Fuchs et al, 2009). In this way, maps may be used to raise awareness of flooding, by highlighting the communities and individuals at risk, but they also influence planning processes at the local and regional level (Haynes et al, 2007;Hagemeier-Klose and Wagner, 2009). The European Floods Directive (FD) (European Parliament and the Council, 2007) therefore defines the mandatory publication of flood maps as well as flood risk management plans as the most important instruments for enhancing awareness and preparedness of citizens.…”

Zielgruppenspezifische Darstellung von Hochwassergefahren und -risiko

“…Gefahren-und Risikokarten stellen aufgrund der Möglichkeit, Prozesse in ihrem raum-zeitlichen Gefüge zu visualisieren, ein Kerninstrument des Hochwasserrisikomanagements und somit der Risikokommunikation dar (Hagemeier-Klose und Wagner 2009;Meyer et al 2012 Dies kann als wichtiger Schritt in der Veränderung hin zu einem integrierten Hochwasserrisikomanagement verstanden werden (Merz et al 2007). Im Vergleich zu textlichen Darstellungen handelt es sich bei kartografischen Risiko-und Gefahrendarstellungen um ein Kommunikationsmedium, das bei entsprechender Gestaltung ein hohes Maß an Interesse wecken sowie von einer großen Bandbreite an Personen interpretiert werden kann, und somit einerseits für eine effektive Informationsvermittlung sowie andererseits als einfach zugängliches Instrument zur Information der Bevölkerung über individuelle Hochwassersituationen geeignet ist (Bell und Tobin 2007;Cao et al 2016 Im Detail schreibt die Hochwasserrichtlinie für die Risikokarten folgende Inhalte vor: (1) Ausweisung der Anzahl der betroffenen Einwohnerinnen und Einwohner, (2) Art der wirtschaftlichen Tätigkeiten in den potenziell betroffenen Gebieten, (3) Anlagen gemäß Anhang I der Richtlinie 96/61/EG (Anlagen, die zu einer unbeabsichtigten Umweltverschmutzung führen können) sowie (4) weitere Informationen, die von den Mitgliedstaaten als sinnvoll erachtet werden (Europäische Kommission 2007).…”