This Project contains three Sites in the area between the rivers Rhein and Maas. Two Sites called Blausteinsee and Echtzer See are located in the Rhenish lignite district and are renaturized lignite mines. The third Site called Bosmolenplas is located near Maas River in the Dutch municipality Maasgouw and has originated from gravel and sand quarrying. For years, all three Sites have been used for countless training dives conducted by diving schools in the area. Moreover, active lignite mines nearby may have an impact on the water quality and biodiversity. Our volunteer team's participation in Project Baseline was mainly driven by a wish to support our personal observations of decreasing water quality and biodiversity with sound data. Our team will first focus on the measurement of water temperature and visibility since these parameters can be obtained with ease. In the future we plan to monitor more sophisticated parameters like carbon dioxide saturation, algae growth, saprobic index etc. The Project is principally not limited to the three mentioned Sites. We plan to include more sites as resources allow.