Adaptive Chemical Mixing Resolution to Accelerate Water Quality Simulations without Accuracy Loss

EPANET 2.2’s Lagrangian algorithm, the industry standard for modeling quality in water distribution systems, depends on a proper temporal discretization to balance accuracy and running time. This article introduces a modification to the algorithm that aims for higher accuracy with smaller computational efforts. The modification adaptively accumulates, mixes, and releases water parcels in sync with heterogeneities in upstream pipes instead of flattening them in accordance with a prescribed time step. By independently modifying the temporal resolution at each node in the network, this adaptive technique decouples the level of detail necessary at different locations and for different calculations. Experiments with three different test models, ranging from small to large, demonstrated that considerable efficiency can be gained, especially in situations where rapid concentration changes occur in the network. Even in simulations with gradual changes, the adaptive technique achieved similar levels of accuracy in less than half the time.