Soni, Lubaina ， Farrell, Claire ， Fletcher, Tim D. ， Szota, Christopher
2025-08-09 URBAN WATER JOURNAL 2025 22(卷), 7(期), (761-776页)
Green roofs are increasingly used for stormwater management. Rainfall retention is influenced by climate and green roof design. Deeper substrates and greater plant density increases water storage capacity on green roofs, in hot/dry climates. Higher plant density and evapotranspiration leads to greater drought stress. Designing green roofs with runoff zones (directing water towards plants) potentially reduce drought stress. An existing water balance model was modified to simulate rainfall retention and plant drought stress for 30-year period for different green roof designs; density (unplanted, half-planted and fully-planted), depth (150mm and 300mm) and presence/absence of runoff zones in temperate and semi-arid climates. All designs achieved high retention in temperate (>87%) and semi-arid (100%) climates. Plants in semi-arid climate experienced drought stress for 70-120 days annually. Greater density and presence of runoff zones increased drought stress in semi-arid climate. In all green roof designs, rainfall retention was mostly driven by evaporative demand.