The use of Hugin to develop Bayesian networks as an aid to integrated water resource planning*

Integrated management is the key to the sustainable development of Europe’s water resources. This means that decisions need to be taken in the light of not only environmental considerations, but also their economic, social, and political impacts; it also requires the active participation of stakeholders in the decision making process. The problem is to find a practical way to achieve these aims. One approach is to use Bayesian networks (Bns): networks allow a range of different factors to be linked together, based on probabilistic dependencies, and at the same time provide a framework within which the contributions of stakeholders can be taken into account. A further strength is that Bns explicitly include the element of uncertainty related to any strategy or decision. The links are based on whatever data are available. This may be an extensive data set, output from a model or, in the absence of data, can be based on expert opinion. Networks are being developed for four catchments in Europe as part of the MERIT project; these are in the UK, Denmark, Italy and Spain. In each case stakeholder groups are contributing to the design of the networks that are used as a focus for the consultation process. As an example, the application to water management of a UK basin is discussed.