Assessment of modular block stormwater storage systems

Recognising the need for urban drainage solutions to fit a variety of different situations, both ‘hard’ and ‘soft’ approaches have evolved. For stormwater storage, ‘hard’ structures such as modular block systems and concrete chambers have often been found to be more amenable to requirements than ‘soft’ solutions such as open ponds, for example, in cases where space constraints are an issue. In the current studies, two different configurations of modular block storage system were assessed, one with a slotted underpipe connecting between the inlet and outlet, and one without. A combination of experimental and numerical approaches were applied, including tracer studies, and studies using computational fluid dynamics (CFD). The study concludes that the use of an underpipe is likely to minimise the occurrence of sediment and debris deposition, as compared to other alternative arrangements.