Fig. 5. Cumulative runoff hydrographs of selected representative (A) light (1.27 mm), (B) medium (4.06 mm), and (C) heavy (10.08 mm) rain events recorded at 5-min intervals. Lines represent either rainfall (mm) or runoff (mm) from conventional roofs with a gravel ballast (gravel), nonvegetated green roofs with media only (media), or vegetated green roof treatments (vegetated). Values are averages of measurements taken using three tipping bucket rain gauges.