Abstract.To support the transition from traditional flood defence strategies to a flood risk management approach at the basin scale in Europe, the EU has adopted a new Directive (2007/60/EC) at the end of 2007. One of the major tasks which member states must carry out in order to comply with this Directive is to map flood hazards and risks in their territory, which will form the basis of future flood risk management plans. This paper gives an overview of existing flood mapping practices in 29 countries in Europe and shows what maps are already available and how such maps are used. Roughly half of the countries considered have maps covering as good as their entire territory, and another third have maps covering significant parts of their territory. Only five countries have very limited or no flood maps available yet. Of the different flood maps distinguished, it appears that flood extent maps are the most commonly produced floods maps (in 23 countries), but flood depth maps are also regularly created (in seven countries). Very few countries have developed flood risk maps that include information on the consequences of flooding. The available flood maps are mostly developed by governmental organizations and primarily used for emergency planning, spatial planning, and awareness raising. In spatial planning, flood zones delimited on flood maps mainly serve as guidelines and are not binding. Even in the few countries (e.g. France, Poland) where there is a legal basis to regulate floodplain developments using flood zones, practical problems are often faced which reduce the mitigating effect of such binding legislation. Flood maps, also mainly extent maps, are also created by the insurance industry in Europe and used to determine insurability, differentiate premiums, or to assess long-term financial solvency. Finally, flood maps are also produced by international river commissions. With respect to the EU Flood Directive, many countries alCorrespondence to: H. de Moel (hans.de.moel@ivm.vu.nl) ready have a good starting point to map their flood hazards. A flood risk based map that includes consequences, however, has yet to be developed by most countries.

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Uncertainties in the rate and magnitude of sea-level rise (SLR) complicate decision making on coastal adaptation. Large uncertainty arises from potential ice mass-loss from Antarctica that could rapidly increase SLR in the second half of this century. The implications of SLR may be existential for a lowlying country like the Netherlands and warrant exploration of high-impact low-likelihood scenarios. To deal with uncertain SLR, the Netherlands has adopted an adaptive pathways plan. This paper analyzes the implications of storylines leading to extreme SLR for the current adaptive plan in the Netherlands, focusing on flood risk, fresh water resources, and coastline management. It further discusses implications for coastal adaptation in low-lying coastal zones considering timescales of adaptation including the decisions lifetime and lead-in time for preparation and implementation. We find that as sea levels rise faster and higher, sand nourishment volumes to maintain the Dutch coast may need to be up to 20 times larger than to date in 2100, storm surge barriers will need to close at increasing frequency until closed permanently, and intensified saltwater intrusion will reduce freshwater availability while the demand is rising. The expected lifetime of investments will reduce drastically. Consequently, step-wise adaptation needs to occur at an increasing frequency or with larger increments while there is still large SLR uncertainty with the risk of under-or overinvesting. Anticipating deeply uncertain, high SLR scenarios helps to enable timely adaptation and to appreciate the value of emission reduction and monitoring of the Antarctica contribution to SLR.

Within the context of the European Flood Risk Management Directive, adopted in 2007, the European countries are required to prepare flood hazard and flood risk maps before 2014. The Exchange Circle on Flood Mapping (EXCIMAP) has made an inventory of flood mapping practices in Europe. This inventory has resulted in a ‘Handbook on Good Practices for flood mapping in Europe’ and an ‘Atlas of Flood maps containing examples from 19 European countries, Japan and USA’. This paper highlights the main conclusions of the EXCIMAP Handbook and Atlas, regarding the most appropriate ways to present flood‐related information. Distinction is made between different types of use and users, such as land‐use planning, emergency planning, flood risk management, reinsurance and the general public. Many countries disseminate flood maps (mainly flood extent maps) and flood hazard maps (depth or depth–velocity combinations) already via Internet. Many European rivers are part of transboundary water systems. Therefore, uniform approaches in flood (risk) assessments, map legend and presentation are urgently needed.

The Delta Programme consists of strategies to protect the Netherlands against flooding and to safeguard fresh water supply while anticipating climate change. The programme is aimed at avoiding a disastrous flood, rather than responding to it after the event. This requires a multigovernmental approach, strategies dealing with uncertainty and adequate institutional arrangements to guarantee future-proof implementation. The Delta Programme includes updated standards for flood protection, a policy framework regarding flood-proof urban (re)development and efforts to improve disaster management. Uncertainties about the future climate, population, economy and society are to tackled by an adaptive way of planning i.e. maximizing flexibility, keeping options open and avoiding 'lock in' . The multifunctional design of these measures increases societal 'added value' (regarding nature, recreation or urban development) and enhances acceptance. The Delta Commissioner directs this multigovernmental process, monitors progress, reports to Parliament every year and takes the necessary steps when problems arise. From 2020 onwards, a Delta Fund of about 1 billion EUR per year will provide stability in financial resources. The new Delta Act forms the legal basis for the programme, the Commissioner and the Delta Fund.