AWWA ACE54269

The water distribution system of the City of Owen Sound, Ontario was modeled with Haestad Methods' WaterCAD water distribution modeling software with the objective of accurately predicting the propagation and decay of chlorine residual in thesystem. Water quality problems require a different modeling approach than hydraulic problems. In water quality problems, the typical concern is with quality in remote sections of pipe, under average day conditions and off peak demands. The proper allocation of demand in space is especially dependent on which type of problem is being solved. If accurate demand data is not available, reliable water quality modeling cannot be performed. When water meter records are incorporated on a user-by-user basis, the model can approximate water ages, and by extension water quality, in remote parts of the system. However, demandvariability is the "Achilles' heel" of water quality modeling. The results of this study indicate that it is difficult to accurately predict water quality, with respect to chlorine decay, in a water distribution system when field data are not collected under controlled conditions, even if all relevant and available information is incorporated and demands are allocated to nodes on a user-by-user basis. However, it is possible to identify potential problem areas with reasonable accuracy. Specifically, it is possible to locate where in the distribution system chlorine residual drops below the minimum requirement of 0.2 mg/l. Includes 23 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

06/01/2001

Number of Pages:

19

File Size:

1 file , 360 KB