This study assesses the relative influence of four independent variables on green roof hydrological performance under rainstorm conditions. Twenty-four extensive green roofs representing all combinations of the following four design factors were used: native meadow species versus Sedum; mineral-based versus biologically derived planting medium; 10-cm versus 15-cm depth; and irrigation provided daily, sensor controlled, or not at all. From events covering the period May–October in 2013 and 2014, mean values were determined for the seasonal volumetric runoff coefficient ($C_{\text{vol}}=0.4$), peak runoff coefficient ($C_{\text{peak}}=0.12$), and U.S. Natural Resources Conservation Service (NRCS) curve number ($\mathrm{CN}=94$). Irrigation had the largest overall impact: daily irrigation increased $C_{\text{vol}}$ to 0.5 compared to 0.3 for systems with sensor-controlled or no irrigation. The biologically derived planting medium, composed of a high proportion of aged wood compost, made a significant improvement, maintaining $C_{\text{vol}}$ of 0.3 compared to 0.4 for the mineral-based product in the modules without irrigation. A similar pattern was found in the NRCS curve numbers.

+More

seasonal volumetric runoff coefficient span classequationtdmath displayinline overflowscrollmrowmsubmicmimtextvolmtextmsubmomomn04mnmrowmathspanspan classformulalabelspan peak runoff coefficient span classequationtdmath displayinline overflowscrollmrowmsubmicmimtextpeakmtextmsubmomomn012mnmrowmathspanspan product aged green roof hydrological biologically derived planting native meadow resources conservation service nrcs curve number span classequationtdmath

Liat Margolis,Brent Sleep,Jennifer Drake,Jenny Hill, ,.Influences of Four Extensive Green Roof Design Variables on Stormwater Hydrology. 1 (0),.

Liat Margolis,Brent Sleep,Jennifer Drake,Jenny Hill, ,"Influences of Four Extensive Green Roof Design Variables on Stormwater Hydrology" 1

Liat Margolis,Brent Sleep,Jennifer Drake,Jenny Hill, ,"Influences of Four Extensive Green Roof Design Variables on Stormwater Hydrology"