https://doi.org/10.5194/hess-2020-332 Preprint. Discussion started: 16 July 2020 c Author(s) 2020. CC BY 4.0 License. The Value of Citizen Science for Flood Risk Reduction: Cost-benefit Analysis of a Citizen Observatory in the Brenta-Bacchiglione Catchment Michele Ferri1, Uta Wehn2, Linda See3, Martina Monego1, Steffen Fritz3 5 1Alto-Adriatico Water Authority (AAWA), Cannaregio 4314, 30121 Venice, Italy 2IHE Delft Institute for Water Education, Westvest 7, 2611 AX Delft, The Netherlands 3International Institute for Applied Systems Analysis (IIASA), Schlossplatz 1, 2361 Laxenburg, Austria Correspondence to: Michele Ferri (
[email protected]) Abstract. Citizen observatories are a relatively recent form of citizen science. As part of the flood risk management strategy 10 of the Brenta-Bacchiglione catchment, a citizen observatory for flood risk management has been proposed and is currently being implemented. Citizens are involved through monitoring water levels and obstructions and providing other relevant information through mobile apps, where the data are assimilated with other sensor data in a hydrological-hydraulic model used in early warning. A cost benefit analysis of the citizen observatory was undertaken to demonstrate the value of this approach in monetary terms. Although not yet fully operational, the citizen observatory is assumed to decrease the social 15 vulnerability of the flood risk. By calculating the hazard, exposure and vulnerability of three flood scenarios (required for flood risk management planning by the EU Directive on Flood Risk Management) with and without the proposed citizen observatory, it is possible to evaluate the benefits in terms of the average annual avoided damage costs.