Due to the randomness and complexity of the actual operating environment

the parameters of water distribution network (WDN) hydraulic model are uncertain. Based on the Monte Carlo stochastic simulation method

this paper proposes an uncertainty analysis method for WDN hydraulic model considering the correlation of parameters. Correlated parameters were regarded as random variables with specified correlation coefficients. In the Monte Carlo random sampling

independent normal random number sampling was performed

and then the independent normal random number was converted into the correlated random number by inverse-Orthogonal transformation and inverse-Nataf transformation. The correlated random number was used as the model parameter value for hydraulic calculation. The effect of the correlation and uncertainty of pipe roughness on the uncertainty of the node pressure and the pipe flow in the WDN hydraulic model was studied. Case analysis showed that the correlation of pipe roughness had a significant impact on the uncertainty analysis results. The differences of the average fluctuation values of node pressure and pipe flow were more than 70% and 60% separately in correlated and independent conditions. Therefore

the correlation between model parameters should be considered in the uncertainty analysis of WDN.