Calibration and Testing of Simple Mass Balance Model for Quantifying Stormwater Management Benefit of an Extensive Green Roof

A simple mass balance based model for quantifying stormwater management benefits of an extensive green roof was developed and tested based on data from Lawrence Technological University. Model simulated green roof runoff peaks and volume agreed with those measured between April – September 2008 within a factor of 0.97–1.4 and 0.8–1.6 respectively.;The objective of limiting roof runoff peaks from 2 to 100 year design storms to equal or be lower than the corresponding pre-developmental peaks for the tested regional conditions was not met with the green roof alone. Provision of an additional storage of 40 m3/1000 m2 green roof area in series with the green roof is expected to be able to achieve this objective. The developed procedure is expected to be useful for the assessment of stormwater management benefits of extensive green roofs in other geographical locations.