Quo vadis water distribution model calibration?

Hydraulic water distribution system (WDS) simulation models are widely used by planners, water utility personnel, consultants and many others involved in analysis, design, operation or maintenance of water distribution systems. Similarly, water quality models that work in concert with hydraulic models are now commonly used to simulate the dispersion of and changes in water quality in a water distribution network. As with all mathematical models, WDS model parameters (hydraulic and water quality) require calibration before useful results may be obtained. Nowadays, automated calibration procedures are widely available for hydraulic models, but less so for water quality models. Even when they are available as commercial software, the use of these advanced calibration tools in engineering practice has been limited. This paper provides a review of model calibration approaches and considers future challenges and directions.