As part of the low countries and with one of the highest population densities worldwide, the Flemish region has experienced a long history of flooding causing tens of millions euro damage each year. In response to this, water managers invested over the past decade in flood modelling and mapping with a fluvial origin. In recent years, pluvial flooding has also occurred numerous times in Flanders, but a region-wide map describing these processes more in detail in terms of extent, depth and probability was lacking. Following a pilot-study in 2016, the VMM undertook in 2017 the VLAGG1- project to develop a region-wide, high-resolution pluvial flood map for Flanders. Via a combination of state-of-the art methodologies and web technologies, a draft flood map was presented to a broad reviewing community across Flanders, who were then able to improve it further by adding local knowledge on known flooding and more detailed data on key hydraulic structures. In a three month period, over 7000 additions were made by 370 delegates from 165 organizations that have been incorporated into, and significantly improved the quality of the final flood maps which are due to be published in 2019.

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Abstract. Based on the results of recent studies a renewed vision for flood risk management in Flanders took shape under the name of multi-layered water safety. The multi-layered water safety aims at reducing flood risk to a socially and economically acceptable level through an optimal mix of protective, preventive and preparedness measures, in which all actors in flood risk management face up to their responsibility. A new approach to develop a flood risk action plan based on the vision of multi-layered water safety was applied to the pilot case of the catchment of the Maarkebeek. Using a methodology based on quantitative economic as well as social risk values, potential measures are assessed taking climate change and land use projections into account. Measures and combinations that have a positive (or marginally but acceptable negative) cost-benefit ratio and a large social benefit are retained. These serve as a starting point for the debate on flood risk management with all the actors and for the consultation of the VWDNHKROGHUV $V D UHVXOW RI VHYHUDO DFWRU PHHWLQJV D µULYHU contract ¶ ZDV drafted. The river contract is a commitment of all actors to realise the listed measures, securing the collaborative effect. The river contract is an integrated response to the flood risk problem at catchment scale and aims at providing solutions to all affected households. This approach, applying multi-layered water safety to a local river catchment, combines an objective model-based assessment with intense stakeholder deliberation resulting in a widely accepted and objectively effective action plan i.e. the river contract, to manage flood risk in an efficient and sustainable way.

Abstract. Today, water authorities face a set of water management challenges, related to new European policies, climate change adaptation, land use planning, urban wastewater and storm water management. In response to these evolutions and anticipating on fast changing IT-technologies, Flanders Environment Agency has developed a set of next generation tools for operational hydrology. These tools are flexible, open and integrate all major components of the water system (principle toolbox). Rather than just providing a set of tools, the toolbox is integrated into existing information systems by the latest technologies using open standards and web protocols. Currently, the toolbox is used to establish a regional hydrological model set for Flanders. This large scale model will produce information on the hydrological status (runoff, subflow, infiltration, soil storage, etc.) at any location in Flanders. Furthermore, an interactive web-application of the toolbox was developed to enable hydrological modelling through the internet. Besides the fulfilment of the modelling needs of the Flanders Environment Agency, the initiative aims to foster collaboration, not only between governmental agencies with operational duties in water management, but also between the different communities in support of operational hydrology.