| Popis: |
The validity of a hydraulic network model of a water distribution system depends largely on the accuracy of input data and the assumptions made in developing the model. Although much of the data can be obtained with a high degree of certainty, certain parameters exist that are either not readily available or difficult to obtain. Such parameters typically include pipe roughness factors and nodal demands and their spatial and temporal distribution. As a result of the difficulty of obtaining economic and reliable measurements of both of these parameters, final model values are normally determined through the process of model calibration. Model calibration involves adjustment of these and other uncertain network model parameters until the model results closely approximate actual observed conditions as measured from field data. This article describes a seven-step procedure for optimal calibration of water distribution network models. Historically, one of the most difficult steps in the process has been the final adjustment of pipe roughness values and nodal demands through the process of microlevel calibration. With the advent of recent computer technology, it is now possible to achieve good model calibration with a reasonable level of success. As a result, little justification remains for failing to develop good calibrated network models before conducting network analysis. Keywords: microcalibration; water distribution system; macrocalibration; pipe roughness factors; genetic algorithms; optimization |
