Nature based stormwater management solutions for housing area – Case study of roof garden implementation

Abstract

Roof gardens/green roofs are more and more present in built environment due to its diverse potential in mitigating negative environmental effects. Under the umbrella of the Nature Based Solutions, roof gardens are applied for precipitation detention in urban catchments. This research deals with housing area in the city of Niš, Serbia, where flat gravel roofs are converted to pitched ones. The assessment of water quantity retained in the roof, and released as runoff is conducted for the previous, present and potential rooftop condition i.e. roof garden. The specification from a manufacturer is used to simulate roof garden conditions. To assess the urban water cycle main components at the rooftop level, the daily water balance model is used for one year period. The simulation results for the pitched roof are assembled from the inclined roofs due to limitations of the applied simulation model. A set of roof efficiency indicators is introduced to quantify role of each rooftop cover to relieve the roof runoff load from the stormwater management system. According to three of four considered roof efficiency indicators, the roof gardens performed best in the studied area.