Potential use of dam sediment for soil construction in urban greening: agronomic fertility and environmental harmlessness
Résumé
There is today a growing demand to develop green spaces in city, as they provide a support for biodiversity and can contribute to ecological connectivity with surroundings. Greening urban areas requires large amounts of arable soil that is a non-renewable resource. The purpose of our study is todetermine whether river dam sediments can be used as alternative materials to preserve soil resource in urban greening. Indeed, sediments are natural materials coming mainly from soils erosion available in large volumes. Sediments are composed of elementary mineral and organic particles. Each year in France, several hundred thousand cubic meters of sediments are dredged from EDF hydraulic power installations to ensure their correct operation, and returned to the river to respect the sedimentary continuity. In some cases, sediments may not be returned to water. Then, ways of valorization are sought. Most often they do not contain anthropic contaminants, in relation with their origin, far fromhuman activities (Brochier et al., 2016), but in some cases, they could contain traces of heavy metalscoming from the natural geochemical backgrounds.