*3.2. Stage 1: Problem Characterization*

The first step was to identify the most pressing bio-physical and socio-economic issues [16]. Climate change scenarios and their impacts on the cities under study were required. In most large European cities, climate change predictions are available [17] and climate plans that address their major concerns with regards to climate change adaptation and/or mitigation [1].

In the current case studies, the downscaled climate-model projections used were developed by the FIC (Climate Research Foundation) [18], while Bristol used also climate data derived from UK Climate Change Projections 2009 (UKCP09) [19]. Local climate action plans were considered, as well as the conclusions from local workshops conducted to address the most pressing issues identified by stakeholder engagement in each site. A common workshop structure was proposed and followed by each city, adapting details according to their specific needs, such as the number and background of members. The main structure followed in the first workshop included context introduction, a discussion among partners regarding the approaches taken, strategies to be included, and the prioritization method to follow. The second workshop focused on reviewing the expected outcomes in terms of hazard reduction and the presentation and discussion of detailed strategies already identified by the city council.

The outcome, presented in the results section, was a selection of the extreme events and hazards to address and the development of a longlist of measures that are expected to alleviate the impacts of the former).

The second step consisted in selecting and applying a categorizing criterion to create strategies that are aligned with the objectives sought. In the context of urban services, the following options were proposed:


Researchers of the Barcelona case study decided to categorize strategies by the type of hazard they targeted, namely pluvial flooding and Combined Sewer Overflow (CSO), according to the objective of the city's stakeholders to focus on the reduction of those impacts. Similarly, the Bristol case study chose to categorize strategies by the predominant hazards identified in the city, which were pluvial and fluvial flooding and CSO events. These issues were forecasted to cause significant disruption to many aspects of the communities, in particular to the transport network, power supply, and properties located in high-risk areas.

This classification permits comparison of measures that "compete" against each other to alleviate one specific hazard instead of an overall prioritization of measures earmarked for different issues.
