ABSTRACT
The study defines the impact of the inlet channel’s bottom fall on the relevance of the use of its storage capacity in order to reduce the required usable volume of a multi-chamber storage reservoir. Tests using hydrodynamic simulations were conducted in three model catchment areas with various shapes and with various systems of channels, using hydrodynamic software SWMM 5.1. The obtained results confirmed the assumptions as to the relevance of including the storage volume of the inlet channel. The demonstrated significant share of channel holding has a measurable application effect because it makes it possible to considerably reduce the required usable volume of the multi-chamber storage reservoir, and even to abandon its construction in extreme cases. It turns out that the effectiveness of the use of the storage volume of the inlet channel determined in the tests is greater when the fall of this channel is lower. This results from an obvious phenomena because when the value of the inlet channel’s bottom fall decreases, sewer backwater reaching increasingly further is observed which makes it possible to incorporate a longer section of the sewage network to accumulate the sewage, ensuring its gravitational operation. It was demonstrated in the course of simulation tests on model catchment areas of various shapes and systems of the sewage network that the greatest benefits from the use of channel holding are observed: (1) with a high level of the location of the edge between chambers towards the bottom of the inlet collector, (2) with substantial values of the flow rate β reduction coefficient and (3) with a dense system of channels of the storm water drainage system. Due to the simple and cheap manner of using the storage volume of the inlet channel, it is advisable to include this phenomenon when developing design concepts, regardless of the network’s hydraulic parameters and the hydrological parameters of the drained area.
