Denis Nono, Philimon T Odirile, Bhagabat P. Parida, and Martine Nyeko
Sampling Design, Hydraulic and Chlorine Decay models, Calibration, Sensitivity Analysis
The accuracy and confidence in simulation results by water distribution system (WDS) models are normally affected by uncertainties of input parameters. Efforts to reduce the uncertainties have been through calibration of the model. However, in WDS modelling of large pipe networks, data collection for model calibration is very expensive and requires selection of appropriate nodes and pipes for their measurement. This study proposed a new approach to determine the most sensitive pipes and nodes in a water distribution network for selection as points for calibration of hydraulic and chlorine decay models. The approach is based on computation of sensitivity indices of model input parameters by applying method of Elementary Effect. The nodes or pipes with high values of sensitivity indices of the input parameters are selected for model calibration. Application of the proposed sampling approach gave more reliable results compared to the most widely used derivative based method of sampling design for calibration of WDS models. The proposed approach can also be applied to determine appropriate positions in the pipe network for monitoring of pressure, flow and chlorine concentration for operation and management of the WDS.