ANALYSIS OF SPATIAL VARIABILITY FOR STORMWATER CAPTURE TANK ASSESSMENT

Stormwater tank design and installation is one of the most suitable actions to undertake as a strategy for the quantity and quality control of surface urban runoff during a rain event. In the present work, the quality efficiency of a stormwater capture tank in a sewer system serving a typical Italian urban catchment is analysed on a probabilistic basis, mainly with reference to rainfall space variability on the Tyrrhenian coast side of Italy. In particular, two probabilistic approaches (a simple and a Copula function‐based one) are applied to estimate the average efficiency of such a device to reduce the outflow pollution load into the receiver, varying the net capture tank volume from 0 (when only a combined sewer overflow, CSO, is present) up to 100 m 3 per impervious catchment hectare. In this way, simple expressions to be used for a preliminary sizing of the capacity of a capture tank, without performing complex computational continuous simulations, are provided. Copyright © 2012 John Wiley & Sons, Ltd.