Retrofitting a stormwater retention pond using a deflector island

摘要

Stormwater retention ponds are one of the principal methods to treat stormwater runoff. Analysis ofnresidence time distribution (RTD) curves can be used to evaluate the capability of these ponds fornsediment removal. Deflector islands have been suggested as a means of improving the performancenof retention ponds, due to their diffusing the inlet jet. In this study, the effect of an island on retentionnpond performance was investigated using a physical model of an existing stormwater retention pond.nThe physical model is a trapezoidal pond having top dimensions 4.1 × 1.5 × 0.23 m and side slopes ofn2:1 (h:v). Three different arrangements were studied. The results show that placing an island to deflectnthe influent to a stormwater retention pond does not improve pond performance, rather it stimulatesnshort-circuiting. This unexpected behaviour, in relation to previous studies, is considered to be anconsequence of the model pond incorporating sloping walls; which is a novel aspect of this paper.