European Water Framework Directive (WFD) have significant impacts on the water resources management and monitoring all over the Europe. As a part of developing guidance on the process of designation of heavily modified water bodies thirty-four case study projects, carried out in the member states and Norway. Lake Kemijärvi, which is the most heavily regulated natural lake in Finland, was target of Finnish case study. In the case study different tasks of WFD has been carried out, analysed and discussed. As a consequence of analysis lake Kemijärvi was designated as heavily modified.