Flood risk managers need to make and justify decisions on good evidence and sound science, but the data available to them are usually uncertain. It is important to quantify and consider the potential impacts of this uncertainty on the decisions made.

Task 20 has produced:

• A conceptual framework for the process of conducting uncertainty analysis and communicating to stakeholders;
  
  
• Reframe – a software framework for flood risk calculation and computational decision support;
  
  
• UNEEC – an innovative methodology for modelling errors in forecasting situations;
  
  
• Info-gap analysis – new methods for robust decision-making under severe uncertainty.

These tools are intended to be used by managers, who are required to make robust risk-based decisions in both policy and emergency situations, and flood risk modellers requiring guidance on choice of model components and how they should be brought together to analyse uncertainty.

Key words: Uncertainty analysis, risk-based decision-making, conceptual framework, forecasting models