Modern control systems tend to be based on computers and therefore to operate by sending commands to structures at given intervals (discrete time control system). Moreover, for almost all water management control systems there are practical lower limits on the time interval between structure adjustments and even between measurements. The water resource systems that are being controlled are physical systems whose state changes continuously. If we combine a continuously changing system and a discrete time controller we get a hybrid system.We will show how the control action due to the hydraulic behaviour of weirs and gates can help stabilize such a system. @en

Model predictive control (MPC) is a powerful control option which is increasingly used by operational water managers for managing water systems. The explicit consideration of constraints and multi-objective management are important features of MPC. However, due to the water loss in open water systems by seepage, leakage and evaporation a mismatch between the model and the real system will be created. These mismatch affects the performance of MPC and creates an offset from the reference set point of the water level. We present model predictive control based on moving horizon estimation (MHE-MPC) to achieve offset free control of water level for open water canals. MHE-MPC uses the past predictions of the model and the past measurements of the system to estimate unknown disturbances and the offset in the controlled water level is systematically removed. We numerically tested MHE-MPC on an accurate hydro-dynamic model of the laboratory canal UPC-PAC located in Barcelona. In addition, we also used well known disturbance modeling offset free control scheme for the same test case. Simulation experiments on a single canal reach show that MHE-MPC outperforms disturbance modeling offset free control scheme. @en

Combined sewer networks, where both foul water and storm water are transported through the same system, tend to develop into complex networks due to expansion of towns and villages. The transport capacity of these systems is always limited, so occasional controlled spills into surface water, combined sewer overflows (CSO), are part of the normal operating procedure. Occasionally the ideas and rules present in the original design are not respected when the system is extended to cover a larger area. One way to deal with this problem is to implement central control. Another is to add pipes and hardware to bring the extended system into line with the original rules and ideas.We show that for a design rule often followed in the Netherlands, local control does quite well as long as the rule is respected and there are no large variations in precipitation intensity over the area covered by the system. @en