The state forest of La Reine is a humid forest of about 5000 ha located in the south of the plain of Woëvre and at the foot of the Meuse hills in France. Numerous ponds and puddles are scattered throughout the forest and it is crossed by many small, more or less natural streams. Upstream of the forest, these waterways are impacted by human activities (large-scale farming, housing without collective sanitation in particular). Since 2019, the Moselle Basin Workshop Zone has been working on the implementation of a workshop site to understand the bio-hydrogeological functioning of three of these streams, particularly in terms of natural purification. Sampling campaigns are regularly organized in the streams and in ponds.