Figure 1. Plan view of Badalona.
Badalona (Figure 1) is a Catalan city with 215000 inhabitants and an extension of 21 km2 between the coastal mountain range ‘Serralada de la Marina’ and the Mediterranean Sea. The city experiences flash floods during intense rainfalls due to the steep slopes towards the flat urban area, the high degree of imperviousness and the limited drainage capacity. Also, Combined Sewer Overflows (CSO) occurring during rainfall events larger than few millimetres contaminates the sea water.
Which sectors did it involve?
The company Aquatec was the responsible of the Badalona research site. The main partners that were actively involved into the project through continuous interaction and meetings were the municipality of Badalona, the Barcelona Metropolitan Area (AMB) entity, the mixed company for the management of the supra-municipal sewer system and sanitation of the Barcelona Metropolitan Area and the Water Technology Center Cetaqua.
Further local and supra-municipal stakeholders like Technical University of Catalonia, Catalan Water Agency (Agència Catalana de l'Aigua) and Diputació de Barcelona participated during the four project workshops that took place in Badalona and the established Community of Practices (CoPs).
What was done?
The work that was done at the research site included:
- The definition of the specific activities within each WP and the related coordination and management plan
- The prediction of future climate based on decadal climate predictions and long term climate projections. Future rainfall was then statistically downscaled.
- New equipment was installed, several field campaigns were executed and existing water quality and quantity data were gathered.
- A large set of models (a 1D/2D urban drainage coupled model, a sediment transport module, an integrated urban drainage and sea water quality model) was developed, calibrated and validated.
- Full risk assessment together with tangible and intangible impacts was developed according to a detailed Risk Management Process established with local risk owners. Flood risk maps for pedestrians, vehicles and buildings were computed. Also risk for bathing people was assessed.
- Structural and non-structural adaptation measures like new pipes, detention tanks, green adaptation measures and early warning systems were evaluated and prioritized based on both their capacities of reducing risks and impacts and a cost-benefit analysis.
Which were the main results?
Urban flood hazard and risk maps for pedestrians, vehicles and infrastructure were computed for both present and future rainfall. Actual flood damages would increase by 30% due to climate change. Also, the risk for people bathing in contaminated sea water after combined sewer overflows was quantified.
Finally, a prioritization of different adaptation measures was done. For example, a city-scale implementation of the proposed structural measures has higher costs than benefits. On the other hand, it can significantly reduce flood and CSO risks.
What is BINGO’s legacy in Badalona?
The following practical outcomes will remain at the research site:
- Innovative technological solutions to support decision-making processes: a 1D/2D coupled model for urban flooding impact assessment and an integrated sewer and marine model for CSOs impact assessment-
- Risk assessment procedure for urban flooding including specifc hazard criteria, vulnerability indicators and risk matrices
- Flood risk maps for pedestrians, vehicles and buildings to be used by civil protection and other municipal departments
- Conceptual models for Floods and CSO Early Warning Systems
- Direct and indirect flood damage assessment
- Methodology for CSOs pollution estimation based on rain volume
- Risk treatment and cost-benefit analysis of adaptation measures including the cost of inaction
- Report on how collaborative processes (CoP) are crucial in decision-making processes concerning climate change: risk definition and perception and CC adaptation roadmap