Original paper

The study of rooftop connectivity on the rainfall-runoff process by means of a rainfall simulator and a physical model

Isidoro, Jorge M.G.P.; de Lima, João L.M.P.; Leandro, Jorge

Abstract

The influence of rooftop connectivity on the rainfall-runoff process associated to wind-driven rain and storm movement on highly urbanized areas is not yet well known. In order to study it, a rainfall simulator and a physical model of a hypothetical urban area were used to perform laboratory experiments. Thirty different scenarios were studied combining static and moving storms with/without wind-driven rainfall for five rooftops arrangements with different connectivity. These experiments show that rooftop connectivity, storm movement and wind-driven rain have an important effect on urban runoff, leading to changes in the overland flow hydrographs shapes. Increasing rooftop connectivity leads to a reduction in the peak discharge and an increase in the runoff base time. Regarding flood minimization, the lowest peak discharges and the longest runoff base times were obtained for the clustered rooftop arrangement. Wind-driven rain was shown to reduce peak discharges and rising limb?s slopes, thus increasing runoff base times. Wind-driven rain effects are more evident in the static and downstream moving storms.

Keywords

rainfall simulationmoving stormsexperimental methodsrooftop connectivityurban rainfall simulationmoving stormsexperimental methodsrooftop connectivityurban hydrology