Reclamation and restoration of a natural detention/expansion basin with geosynthetic materials

Floods and heavy rains caused by climate change, trigger major problems throughout European cities. It is increasingly urgent to find solutions to mitigate the sudden rise of the water level of rivers. Detention basins are above-ground storage basins or facilities that allow river flow control through attenuation of stormwater runoff.

Ditches along two rivers in Tuscany used as illegal landfills were reclaimed and restored as natural expansion basins. The project started with a temporary detour of the watercourses, surface and deep removal of the stored waste. Secondly, the restoration of the bottom of the new detention basin, followed by the reconstruction of the basin’s bank and the protective embankments.

The embankments were built using a reinforced earth system with uniaxial grids of different sizes. Removable formworks were used to prevent damage to the water-resistant layer; the inner side was waterproofed with a bentonite geocomposite, and finally a geo-mat for slope erosion control.