“…But for those "short" gullies found in the west of Leung King Estate, the hydrograph is expected come in one surge (instead of series of surges for gullies of tens of kilometers long), and it was found that the shape of hydrograph from Mount St. Helen debris flow closely resembles those observed elsewhere for the case of short gullies (Lo, 2003;Takahashi, 1991). In fact, we maintain the shape of the hydrograph of the Mount St. Helen debris flow, not the velocity as claimed by Parry et al (2005). Regarding the volume, as we mentioned earlier we are looking at the worst scenario or the most extreme case.…”