Controller calibration for moveable weirs in sewer systems

One of the main objectives of real time control (RTC) application in combined sewer systems is the reduction of overflow discharges during rain events. For this purpose, adequately controlled moveable regulators, such as gates or weirs, can be placed inside the main trunk sewers for activating the available in-line storage capacity. In this paper, a detailed study on the local control of a moveable sharp-crested weir in sewer collectors is presented. Firstly, an experimental analysis has been carried out for determining the hydraulic behaviour of the regulator, considering both free flow and submerged flow conditions and taking into account the different weir heights occurring during the regulation processes. Secondly, a numerical investigation on the calibration of proportional units for the local control of the weirs has been performed. In particular, a detailed model based on the De Saint Venant equations has been used to describe the hydrodynamic phenomena connected with the RTC of moveable regulators in sewer collectors. A dimensionless approach has also been adopted for the generalisation of the results of the analysis. Finally, a comparison with previous results concerning the control of moveable gate regulators is presented