Performances hydrologiques de trois toitures végétalisées différentes
Résumé
Green roofs have a wide range of applications, including the development of urban ecosystems and reducing volumes and peaks of stormwater. Traditional green roofs have good hydrological performances. However, new configurations have been developed with the aim of maximizing both the retention of rainwater and the evapotranspiration of the vegetation, and further reducing runoff peaks. The hydrological performances of three vegetated experimental roofs installed on the same site are presented: 1) a traditional vegetated roof with storage cells underneath the substrate layer, called TV1; 2) a TV1 configuration supplemented with an underlying storage tank, an outflow regulator and subirrigation wicks, called TV2; and 3) a TV2 configuration without sub-irrigation wicks, called TV3. The results for ninety-one rainfall events are presented, with higher mean rainfall retention rates for TV2 (95%) and TV3 (99%) than for TV1 (87%). As well as for the reduction of runoff peaks, with average performances of 97% and 99% for TV2 and TV3 respectively, compared with 92% for TV1.