The effect of design storm characteristics on low-impact developmentpractices for rainfall run off control

Abstract

An increase in impervious areas leads to change in storm runoff in term of both increased peak
discharges and decreased concentration time, causing urban inundation. To dealing with such a
problem, runoff control at a site surrounding its generated source (Low Impact Development –LID) has
been intensively considered. This paper aims to evaluate effect of design storm characteristics on
performance of various LID scenarios for reduction in both volumes and peak discharges. LID
scenarios are combinations of green roofs, permeable pavements and bio retentions. SWMM model
(Storm Water Management Model) is utilized to compare runoffs of LID scenarios to that of non-LID
scenarios. The results indicate that an increase in returnperiods of storm events induced reduction in
control efficiencies of both rainfall volume and peak discharges. Conversely, an increase in rainfall
durationscaused anincrease in reduction efficiencies of both rainfall volume and peak discharges. The
effect of different time to peakon control efficiency of storm runoff is not obvious.Runoff reduction
efficiency of bioretention is the highest among three LIDs. The outcomes of this paper provide better
understanding for selection and design of LID.
Keywords: SWMM 5.1, LID, Cau Ba river basin, design storms