Potential of storm water storage tank outflow construction in the prevention of sewerage overload

Abstract The impact of a storm water storage tank outflow construction on its required volume is discussed. A dimensioning of the tank by a rational method applied for small sewerage systems is presented. For large systems, subroutines should be developed to take into consideration the construction details of complex storage tanks in the software enabling real time modelling of sewerage systems. Such subroutines can be tested under simple conditions using rational methods of sewerage modelling, including the approach described in the paper. In the example discussed here for two different positions of the sewer delivering to and collecting stormwater out of the tank both the tank required volume and the outflow as a function of time visibly depended on the sewer position. This was proofed for a rectangular chamber storage tank of the same bottom surface area. However, if the bottom surface area and the storage tank height were calculated in such a way to enable the same maximum value of an outflow from the tank for two different positions of the sewer both the tank volume and the outflow as a function of time were proved to be very similar. Concluding the tank volume depends visibly on the construction of outflow, but the height of the tank can be adjusted in such a way to keep the same maximum outflow for different details of the outflow construction. After this adjustment, the volume of the tank was proved to be almost independent of the construction of outflow from the tank