Under the Water Framework Directive, France needs to work harder to reduce water pollution and has been recommended a more frequent recourse to ecological restoration. Constructed wetlands are particularly interesting as they simultaneously improve water quality, contribute to flood protection and promote biodiversity. In this perspective, the researchers of Lyonnaise des Eaux developed the concept of "Libellule" Zone that aimed at creating a biodiversity area that facilitates the removal of residual micro pollutants from wastewater before it is released into the wild. These actions are clearly beneficial to the environment. Unfortunately, this value remains difficult to estimate even today which can constitute a significant obstacle both to the development of this type of action and to their durability. Our aim is to use the "adapted" Habitat Evaluation Procedure (HEPa) to better value these actions. The HEPa bases the evaluation of environmental costs and benefits directly on the ecological impact of the actions carried out. Our main result is that the HEPa method, initially developed to assess environmental costs, can be a useful method to evaluate the benefits stemming from the creation of an artificial wetland. We expect this evaluation to help decision makers to base their decisions on the true value of wetlands.