Effect of a Deflector Island on the Performance of a Stormwater Retention Pond

摘要

Stormwater retention ponds are one of the principal methods to treat stormwater runoff. Analysis of retention time distribution (RTD) curves is one of the widely used ways to evaluate the capability of these ponds for sediment removal. Deflector islands have been suggested as a means of improving the performance of retention ponds, due to their diffusing the inlet jet. In this study, the effect of an island on retention pond performance was investigated using a physical model of an existing stormwater retention pond. The physical model is a trapezoidal pond having top dimensions 4.1m×1.5m×0.23m and side slopes of 2:1 (h:v). Three different arrangements were studied. The results show that placing an island to deflect the influent to a stormwater detention pond does not improve pond performance, rather it stimulates short-circuiting.