In 1989, a programme was developed for the active restoration of acidified and eutrophied softwater lakes and other ecosystems, known as the OBN (Overlevingsplan Bos en Natuur, forest and wildlife survival plan). One of the aims of the plan was to identify the factors involved in the decay and possible restoration of softwater lakes. The research project reported on took place in the context of the OBN. During the period 1993-1998, small-scale experiments were conducted and the restoration of softwater lakes was monitored. This programme explores the opportunities for the restoration of softwater lakes, focussing mainly on sediment and water quality, and vegetation. To contribute to this project, in four softwater lakes the biochemical parameters of the surfacewater are monitored. Sometimes there were measurements before the restoration. After this OBN-project for a long time the lakes are monitored to prevent water quality deterioration. Every year, there were consultations with the managers to take any additional measures, if necessary. In the metadata.pdf you can found more information about the parameters.