PARAMETER-ESTIMATION IN WATER-DISTRIBUTION SYSTEMS BY LEAST-SQUARES

The weighted-least-squares method using sensitivity-analysis technique is proposed for the estimation of parameters in water-distribution sy stems. The parameters considered are the Hazen-Williams coefficients f or the pipes. The objective function used is the sum of the weighted s quares of the differences between the computed and the observed values of the variables. The weighted-least-squares method can elegantly han dle multiple loading conditions with mixed types of measurements such as heads and consumptions, different sets and number of measurements f or each loading condition, and modifications in the network configurat ion due to inclusion or exclusion of some pipes affected by valve oper ations in each loading condition. Uncertainty in parameter estimates c an also be obtained. The method is applied for the estimation of param eters in a metropolitan urban water-distribution system in India.