The project involves the removal of drainage from a wet grassland at the head of a small Breton coastal river watershed in an area subject to nitrogen pressure. Located at the bottom of an hydromorphic valley, the Coat Carriou meadow has been drained by two ditches to allow the plot to be mowed. Collecting runoff from the hillside, the two ditches caused a short circuit in the meadow, leading the nitrate-laden runoff directly to the river stream. The two drainage ditches were filled in with the aim of eliminating the short circuit, allowing all water flowing to spread over the meadow. The aim was to improve the purifying effect of the grassland on the waters from the hillside, while maintaining agricultural activity. The short circuit has effectively been eliminated, allowing all the water on the slope to pass through the wetland where the purifying capacities make it possible to remove all the mineral nitrogen present in the water. As the purification capacities were already optimal before the work, they were not improved, but all water can now be purified. The reduced bearing capacity allow to mow the meadow only in dry years. It has been included in the grazing path of a herd of brittany pie-noir cows, able to graze wet grassland.

The city of Fourqueux (4000 inhabitants) has redesigned its urban space to build social housing. A plot of land has been set up at the heart of this area to collect and manage rainwater from the requalified area. Called water garden, the park collects water from 1.7 hectares of permeable and impervious area to allow it to infiltrate through a succession of temporary basins and a permanent one. It thus avoids the direct discharge of this rainwater into the separative network connected to the Seine. The water garden also acts as a natural space in the heart of a residential area, and allows the history of the municipality to be highlighted through cultural activities and the permanent display of old agricultural machinery.

Due to major developments over the past two centuries, the Eau Morte Valley (a tributary of Annecy Lake) has a hydrosedimentary dysfunction with incised areas and areas with sediment excesses and an alluvial marsh disconnected from flooding. To reduce the impacts of the river's floods on uses, and to prevent the risk of urban areas flooding, a functional restoration programme for the valley has been developed by the federation of municipalities of Annecy lake sources. It was based on the renaturation of the Eau Morte bed, the functional restoration of the Giez marsh and the construction of crossing structures. This work has given the marsh a role as a flood expansion area. This project was also carried out by involving local residents in a process of territorial dialogue so that they themselves would be actors in the area and would participate in its management.