title: Urban drainage models--simplifying uncertainty analysis for practitioners.
abstract: There is increasing awareness about uncertainties in the modelling of urban drainage systems and, as such, many new methods for uncertainty analyses have been developed. Despite this, all available methods have limitations which restrict their widespread application among practitioners. Here, a modified Monte-Carlo based method is presented that reduces the subjectivity inherent in typical uncertainty approaches (e.g. cut-off thresholds), while using tangible concepts and providing practical outcomes for practitioners. The method compares the model's uncertainty bands to the uncertainty inherent in each measured/observed datapoint; an issue that is commonly overlooked in the uncertainty analysis of urban drainage models. This comparison allows the user to intuitively estimate the optimum number of simulations required to conduct uncertainty analyses. The output of the method includes parameter probability distributions (often used for sensitivity analyses) and prediction intervals. To demonstrate the new method, it is applied to a conceptual rainfall-runoff model (MOPUS) using a dataset collected from Melbourne, Australia.
authors.affiliation: Department of Environmental Engineering (DTU Environment), Technical University of Denmark, Building 113, DK-2800 Kgs. Lyngby, Denmark E-mail: luve@env.dtu.dk.
authors.forename: Luca
authors.initials: L
authors.lastname: Vezzaro
authors.forename: Peter Steen
authors.initials: PS
authors.lastname: Mikkelsen
authors.forename: Ana
authors.initials: A
authors.lastname: Deletic
authors.forename: David
authors.initials: D
authors.lastname: McCarthy
mesh_terms: D002947:Cities; D004323:Drainage, Sanitary; D015233:Models, Statistical; D009010:Monte Carlo Method; D035501:Uncertainty