Unbiased and accurate assessment of surrogate measures of hydraulic reliability of water distribution systems

An unbiased investigation is presented of four surrogate reliability measures which are commonly used in the water distribution system (WDS) literature. Each measure substantially reduces the computational effort required to assess the hydraulic reliability of a WDS, in comparison with the highly accurate measures which are available. A series of related looped WDS networks are considered: each network is optimised with respect to the initial construction cost and nodal pressures. The optimal configuration of each network is generated free of any influence from the surrogate measures. The networks are then assessed using each surrogate measure and two highly accurate but computationally intensive measures. The results indicate that by utilising statistical entropy, the reliability of the network can be reasonably approximated, while substantial computational savings are gained