Rural Water - Quarter 1, 2009 - (Page 40)

How can I use a model to solve problems? Basically, models enable you to experiment with alternative solutions to identify the superior solution. By running through many “what if” scenarios, you can eliminate bad solutions, identify good solutions and gain insight into the behavior of your system before you invest any money in solving the problem. Some of the problems include: Pipe sizing. Once you have installed a pipe, it is too late to say “Gee, I should have laid a 12-inch.” You cannot experiment with real pipe sizes in the real system, but in a model, you can experiment with alternative sizes and load them with future demands to see not only what will work today but what will work when demands increase in 20 years. If a pipe is too small, the model will indicate this with very high velocity in the pipe and low pressures downstream of that pipe. Pump selection. Pumps usually represent the largest operating cost for most utilities. Selecting pumps that work well with the system is essential, and energy costing modules in models can assist in performing the life-cycle A water system hydraulic model can take the dirty work out of solving a wide range of water distribution hydraulic problems. costing need for intelligent pump selection. Sometimes, pumps that work well alone do not run efﬁciently with other pumps. Modeling can identify those mismatches and help you avoid them. Emergency planning. Distribution systems need to work well even when there is a pipe break, pump failure or a power outage. You cannot afford to simulate an actual pipe failure but with a model, you can simulate how your system will respond during an outage. Sometimes, the model calibration work will identify mistakenly closed valves or pumps not running on their curves. Pressure zone layout. In hilly terrain, it is difﬁcult to operate a system that will provide pressures that are not too high at low points and not too low at high points. Models can be used to simulate pressures in the system for a wide range of pressure zone boundaries, tank levels and PRV (pressure reducing valve) settings to identify the system that best serves the customers. Water quality mixing. In systems with multiple sources, the water quality can vary throughout the system. Customers often complain when the taste and odor of their water varies. By running a water quality simulation with a model, you can see which customers are receiving water from which sources and how that changes with time of day and pump operation. There are often surprises with the results of the runs. A water system hydraulic model can take the dirty work out of solving a wide range of water distribution hydraulic problems. With tens of thousands of dollars at risk with each decision a utility manager makes, use of a model to provide decision support more than justiﬁes the investment in the model. 40 • First Quarter 2009 402705_AYMcDonald.indd 1 10/2/08 11:07:31 AM http://www.aymcdonald.com

Table of Contents Feed for the Digital Edition of Rural Water - Quarter 1, 2009

Rural Water - Quarter 1, 2009 Contents From the President Question & Answer: Water Conservation in the Home Avoiding the Humpty Dumpty Approach to Data Backup From the CEO What the Future Holds Asset Management for Small Communities Understanding Your Surface Water Source: The Rivers Hydraulic Models Expeditionary Water Packaging System Graces Delta The Rural Water Rally in April Training in Hawaii Regulatory Update Rural Water Releases Report on Water Infrastructure Projects and Economic Stimulus Legislation Throwing My Loop Advertisers.com Index to Advertisers

Rural Water - Quarter 1, 2009

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