Incorporation of prior information on parameters in inverse transient analysis for leak detection and roughness calibration

Abstract

Leak detection and calibration of hydraulic models for water distribution systems (WDS), including the pipe roughness and other parameters, is undoubtedly a critically important issue. This paper first briefly reviews the relevant literature. After addressing some general issues regarding prior information (PI) on calibration parameters, an inverse transient model, capable of detecting leaks and internal pipe roughness in WDS, is presented. The classic objective function of the weighted least squares type is generalized by adding terms accounting for PI on calibration parameters. The methodology presented is general in that it can be applied to any WDS inverse model. It is then shown that PI, when used in a certain way, conditions the inverse problem and thus improves the solution obtained. As a part of the suggested approach, a procedure for careful and effective use of PI on the parameters in inverse transient problems is suggested. Finally, the methodology is applied to three case studies, leading to some general conclusions about the value and use of PI.