Lake ecological assessment systems and intercalibration for the European Water Framework Directive: Aims, achievements and further challenges

Abstract The Water Framework Directive (WFD) has been published in 2000 and the process of its implementation has created a new paradigm in the understanding of ecological status of water bodies in Europe. The Directive explicitly requires that ecological status is assessed through the analysis of various characteristics of aquatic flora and fauna. An Intercalibration exercise is foreseen to identify and resolve significant inconsistencies between the ecological quality classifications of EU Member States to ensure that the obligation to reach good status has the same meaning throughout Europe. The results of the first Lake Intercalibration exercise (2003-2008) are the setting of reference conditions and class boundaries for phytoplankton biomass metrics for all lake intercalibration types and all geographical regions of the EU. Work on macrophyte assessment methods has been carried out in the Alpine, Central/Baltic and Northern region, while only Alpine and Mediterranean countries have succeeded to develop and harmonize phytoplankton composition assessment methods. The aim of the second phase of intercalibration (2008-2011) is to close these gaps and improve the comparability of the results in time for the second river basin management plans due in 2015.