Management of the diatom monitoring networks in France

An overview is presented of the development of a biological diatom index (IBD) as one of the means for those managing water quality in France to improve knowledge about the biological quality of watercourses. The decision to make this index applicable to the whole French hydrographical, network, and in particular the National Basin Network, was agreed by the Agences de l'Eau and Cemagref in 1994 and led to the first version in 1995. The regular update of software for calculation of indices based on the IBD and the existence of a users' network have led to numerous practical applications. Moreover, the Agences de l'Eau have since 1996 run application programmes on the National Basin Network, in this way completing the initial set of data. Re-examination of the complete set of data at the end of 1998 and tests on different calculation options of the IBD led to a third version of the index, which became the standard in June 2000. Various steps were taken by the Agences de l'Eau, Cemagref and other partners so that the IBD could be implemented rapidly for the surveillance networks. These include production of the determination key and specific IBD index calculation tools, training programmes and several projects related to long-term storage of information, such as the creation of a collection of samples and slides and a national database for the inventories. These activities are supervised by a Group of Scientific Interest of Diatoms of Continental Waters, which has, since its creation, managed an IBD intercomparison exercise with the Association des Diatomistes de Langue Francaise. These initiatives have led to the introduction of the IBD in the Hydrobiology Accreditation Programme of the Comite Francais d'Accreditation (COFRAC).