European Early Warning Systems for coastal floods: User needs, system availability and pertinent policy and legislation

Abstract

The present contribution aims to assess the need for a pan-European Early Warning System (EWS) for coastal floods, and more specifically, to: a) gauge user needs, using a structured questionnaire survey; b) collate the technical specifications of available European EWSs for coastal floods; c) assess the coherence between stated user needs, the specifications of the European EWSs and the existing policy imperatives and legal requirements. The questionnaire survey showed that: the majority (>70 %) of the respondents does not currently use EWSs; most respondents are keen on a pan-European EWS for coastal floods which would include impact assessments as well as event-based flood notifications; and there is a low respondents' familiarity with the relevant international and EU policy and legal frameworks. Regarding the available EWS in Europe, their vast majority provide forecasts/warnings on the basis of Total Water Levels (TWLs) without considering the flood characteristics and impacts; this is inconsistent with both the stated user needs and the policy and legal framework that require risk and impact assessments based on the flood extent, flow depth and velocity. Moreover, there is a ‘polyphony’ in terms of the technical/operational characteristics of the EWSs. Finally, there is an apparent increase in policy and legal requirements for expansion and coherent development of tools for reducing coastal flood risks, including monitoring, assessment, management and the development of integrated EWSs. Generally, there is low coherence between the needs of potential end-users, the characteristics of the available EWSs and the pertinent policy and legislation frameworks.