The present work describes a procedure for the evaluation of the optimal number, position, configuration, and sizes of detention tanks in urban drainage networks, to decrease the maximum flow depths and velocities for an assigned return period and to comply with the local design requirements. Each candidate solution of the optimization problem is evaluated by means of a semidistributed hydrological model in which the kinematic wave is used as flood routing model, whereas the variational approach is used to evaluate the critical flow characteristics corresponding to a given return period. The procedure, which makes use of a genetic algorithm to search for the optimal solution among the candidates, is applied to a case study drainage network, considering superpipe-based detention tanks as detention systems. The results indicate that these tanks are effective in the rehabilitation of the drainage network and that the cost of this intervention is substantially lower than that corresponding to the upgrading of existing pipes
1 March 2011 in Civil Engineering and Environmental Systems
Water distribution systems are vulnerable to intentional contamination: in this paper, optimising the placement of a set of monitoring stations to promptly detect this type of attack is considered. Due to the uncertainty about the place and the time of the beginning of the attack, and the inherent variability of the hydraulic conditions throughout the water distribution network, the impact probability distribution (IPD) has been defined in order to take into account the random variability of the conventional measures of impact. Two different approaches for the optimal placement of the monitoring stations are compared: the first minimises the expected value of a conventional damage measure, while the second minimises a given percentile of the IPD. The two approaches are applied to a real-world case study, showing their feasibility.
In recent years, the interest towards the use of pumps operating as turbines (PATs) for the generation of electrical energy has increased, due to the low cost of implementation and maintenance. The main issue that inhibits a wider use of PATs is the lack of corresponding characteristic curves, because manufacturers usually provide only the pump-mode performance characteristics. In the PAT selection phase, the lack of turbine-mode characteristic curves forces users to expend expensive and time-consuming efforts in laboratory testing. In the technical literature, numerous methods are available for the prediction of PAT turbine-mode performance based on the pump-mode characteristics, but these models are usually calibrated making use of few devices. To overcome this limit, a performance database called Redawn is presented and the data collected are used to calibrate novel PAT performance models.