en Research Paper Research Paper A novel approach to determine optimal sampling locations under parameter uncertainty in a water distribution system (WDS) for the purpose of its hydraulic model calibration is presented. The problem is formulated as a multi-objective optimisation problem under calibration parameter uncertainty. The objectives are to maximise the calibrated model accuracy and to minimise the number of sampling devices as a surrogate of sampling design cost. Model accuracy is defined as the average of normalised traces of model prediction covariance matrices, each of which is constructed from a randomly generated sample of calibration parameter values. To resolve the computational time issue, the optimisation problem is solved using a multi-objective genetic algorithm and adaptive neural networks (MOGA-ANN). The verification of results is done by comparison of the optimal sampling locations obtained using the MOGA-ANN model to the ones obtained using the Monte Carlo Simulation (MCS) method. In the MCS method, an equivalent deterministic sampling design optimisation problem is solved for a number of randomly generated calibration model parameter samples.The results show that significant computational savings can be achieved by using MOGA-ANN compared to the MCS model or the GA model based on all full fitness evaluations without significant decrease in the final solution accuracy. sampling design, water distribution model, calibration, genetic algorithm 48 57 http://ijce.iust.ac.ir/browse.php?a_code=A-10-952-5&slc_lang=en&sid=1 Kourosh Behzadian 180031947532846006002 180031947532846006002 No Abdollah Ardeshir 180031947532846006003 180031947532846006003 Yes Zoran Kapelan 180031947532846006004 180031947532846006004 No Dragan Savic 180031947532846006005 180031947532846006005 No