Why is uncertainty important?

Water Framework Directive - Requirements

The Water Framework Directive (WFD) provides a European environmental policy basis at the river basin scale. The river basin management and planning process prescribed in the WFD focuses on integrated management, involving all physical domains in water management, all sectors of water use, socio-economics and stakeholder participation. The planning process should move from a more rational-instrumental type of planning to an interactive planning with an open eye for the power of fundamental debate. The uncertainties present in such planning processes are judged of an increasing importance (EC, 2004a). An iterative planning process can deal with these uncertainties, for instance by revising the programmes of measures according to the circumstances (EC, 2004b). As such, the WFD poses new challenges to river basin managers. The traditional physical domain specific and sectoral approaches need to be combined and extended to fulfil the WFD requirements. In practise, the preparation of the river basin management plans prescribed in the WFD is in addition to these new challenges, influenced by uncertainties on the underlying data and modelling results.

A basic principle in EU environmental policy on which the WFD is based is ".. to contribute to the pursuit of the objectives of preserving, protecting and improving the quality of the environment in prudent and rational use of natural resources, and to be based on the precautionary principle ..[1]". Therefore, the holistic concept that is prescribed in the WFD with its integrated approach to natural resources and socio-economic issues requires that uncertainty be considered in the decision making process in order for it to become truly rational.

Uncertainty is addressed in several sections of the WFD document, (Blind and de Blois, 2003). For example, the WFD states with respect to monitoring that “Estimates of the level of confidence and precision of the results provided by the monitoring programmes shall be given ..”. In addition, most of the WFD guidance documents, being more specific than the WFD document itself, explicitly emphasise that uncertainty analyses should be performed. For instance, the guidance document on the planning process (EC,2004a) states: “Uncertainty can be defined as the occurrence of events that are beyond our control. Uncertainty is always an element in the planning process. It arises because the complexity of the many factors involved. In fact, meteorological, demographic, social, technical, and political conditions which will determine the planning process have behaviour patterns not always known with sufficient accuracy. Uncertainty arises mainly due to the stochastic nature of some key elements affecting these processes.” Similarly, the WATECO document on economic analysis states that “Uncertainty on costs, effectiveness and time-lagged effects of measures needs to be dealt with throughout the economic analysis process, and more generally throughout the process of identifying measures and developing the river basin management plan”. However, despite strong recommendations to consider uncertainty aspects, the guidance documents do not include recommendations on how to do so.