A decision support system for the implementation of the Water Framework Directive in the Netherlands: Process, validity and useful information Sandra Junier *, Erik Mostert 1 Delft University of Technology, Faculty of Civil Engineering and Geosciences, Department of Water Management, Stevinweg 1, 2628 CN Delft, The Netherlands 1. Introduction This paper discusses the development and use of a decision support system for the implementation of the European Union’s Water Framework Directive (2000/60/EC; WFD). This directive requires the Member States of the EU to reach a ‘‘good water status’’ by 2015. For surface waters, this includes a good chemical status and a good ecological status. If it is technically not feasible or disproportionately expensive to reach a good status by 2015, deadlines may be extended to ultimately 2027 and objectives may be lowered. The objectives for individual water bodies have to be specified in river basin management plans (RBMPs), which have to be developed involving all interested parties. Moreover, programmes of measures have to be developed to reach the objectives. The WFD posed new challenges for river basin manage- ment and made existing ones more pronounced. They include both institutional challenges, such as the interplay between the different authorities involved (e.g. Junier et al., 2011; Moss, 2004), and technical challenges, such as the definition of ‘good status’ of a water body, how to measure and monitor the e n v i r o n m e n t a l s c i e n c e & p o l i c y 4 0 ( 2 0 1 4 ) 4 9 – 5 6 a r t i c l e i n f o Keywords: Decision support systems Modelling The Netherlands River basin management Water Framework Directive a b s t r a c t This paper discusses the development and use of the first version of the WFD Explorer (WFDE), a decision support system (DSS) for the implementation of the Water Framework Directive in the Netherlands. The paper’s aim is to increase our understanding of the development process of DSSs and the impact the development process has on the perceived validity and usefulness of the DSS. In other words, whether the DSS is seen as representing reality correctly and as fit for purpose and user-friendly. Contrary to the expectations, the WFDE was not used much. Tensions in the development process over the intended users, the level of analysis, the level of ambition and the type of expertise to be included have contributed to doubts over its usefulness and validity. These tensions reflect general tensions in river basin management: different actors will prefer different approaches, and none of these is objectively the best. Whereas guidelines for the development of DSSs can increase awareness of these tensions, resolving these tensions is beyond the power of the developers to control. Guidelines have their use, but also their limitations, simply because they are general and circumstances differ from case to case. # 2014 Elsevier Ltd. All rights reserved. * Corresponding author. Tel.: +31 015 2789916. E-mail addresses: s.j.junier@tudelft.nl (S. Junier), e.mostert@tudelft.nl (E. Mostert). 1 Tel.: +31 015 278 7800. Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/envsci http://dx.doi.org/10.1016/j.envsci.2014.04.004 1462-9011/# 2014 Elsevier Ltd. All rights reserved.