Water Distribution Modeling History – How Did We Get Here?
While other people have hobbies like fishing and golf, one of my hobbies is learning about the history of hydraulics and modeling.
Who Put That Hill in the Way of Our Pipeline?
Pumps are great for lifting water uphill. But the uphill slope from the pump may not be uniform over the length of the pipe (force main, rising main). The elevation of the terminal discharge point may only be slightly higher than the water source. However, if there are one or more hills along the way, it is necessary for the flow to get over the hills.
System Head Curves in Closed Systems
An important step in selecting pumps is developing the system head curve, which gives the head needed to move various flow rates through a pumped system.
How Much Wastewater is Coming Out of That Manhole?
No one wants to see wastewater flowing out through a manhole cover. No one wants wastewater flowing in their street. It can lead to regulatory enforcement actions in most places.
Death to Flow Control Valves
FCVs are used to limit the maximum flow rate through the valve from upstream to downstream. FCVs do not limit the minimum flow rate or negative flow rate (flow from the To Pipe to the From Pipe).
Optimal but Stupid
If you pick up most water-related journals these days, it seems as if half the papers are devoted to applying some optimization techniques to solve some real problem. However, almost none of these methods actually find their way into water engineering and operations. Why is that?
Where Do You Turn When a Problem Becomes a Nightmare?
Years ago, I came home from work one day, turned on the water faucet, and nothing came out. Usually, this would be an indication that there was some water system maintenance work being done in our neighborhood, but I didn’t notice anything unusual on the drive home.
Primitive Tools for Modeling
In any reasonably sized system, it is necessary to solve thousands of simultaneous non-linear equations. Before computers came along, simplifications and approximations were needed to make the solutions possible.
Finding E. coli After Contamination
One of the first papers documenting the occurrence of negative transient pressure in water distribution systems was Walski and Lutes “Hydraulic transients cause low-pressure problems” (Journal AWWA) based on some work we did in Austin around 1990. There have been a number of good papers in the intervening years on fate and transport of contaminants (primarily microorganisms) drawn into the water system as a result of such events.