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Mmajner
April 18, 2016, 03:14 PM
I have a water distribution system modeled in InfoWater. It includes (2) Treatment plants and several booster stations. I have been asked to run a scenario where only the main treatment plant is providing water to the system and the other one is off line. When both are making water the system seems to be working correctly. When I start the scenario the one and only treatment plant providing water some how is not making enough water to keep up with the supplied demand. For some reason it is not picking up the slack to cover the demand when the other station is shut down. Trying to figure out what could cause this issue. The main station should be making additional water to cover the turned off station.

Patrick Moore
April 18, 2016, 03:43 PM
Martin,

How are you modeling the WTP? Is supply limited by use of a FCV or a control statement? You may need to adjust that to get more flow.

If you are not limiting the supply from the WTP reservoir then I would look at what else is controlling the supply out of it. Is it pumps? Are they set to run on timer controls or on some type of level setpoint? If the controls won't pull more water the supply would not increase

Lastly, it may be an issue with the hydraulic grade lines. Water flows form high head to low head to meet demands. If another source has a higher HGL than the WTP it will pull water from the alternate source until that source is exhausted. Take a close look at where the water is coming from to meet the extra demand and what the HGL's are and you can often find out why water was pulled form where it was.

Hope that helps.

Patrick Moore


I have a water distribution system modeled in InfoWater. It includes (2) Treatment plants and several booster stations. I have been asked to run a scenario where only the main treatment plant is providing water to the system and the other one is off line. When both are making water the system seems to be working correctly. When I start the scenario the one and only treatment plant providing water some how is not making enough water to keep up with the supplied demand. For some reason it is not picking up the slack to cover the demand when the other station is shut down. Trying to figure out what could cause this issue. The main station should be making additional water to cover the turned off station.

Mmajner
April 19, 2016, 08:30 AM
I am using PRV on the lines downstream of the pumps with a value in the setting field to limit the pressure in the lines. No settings or controls on the pumps. These same lines produce 4mgd when the other stations are up and running. Any other suggestions.

Patrick Moore
April 19, 2016, 09:12 AM
Martin,

It may be easiest to have us both look at the model. If you would like to do that, please go ahead and submit an email to support@Innovyze.com.

As far as why the WTP is not producing more water, it would appear the most likely explanation without looking at the model is that that the same WTP discharge HGL (based on the PRV) is being outcompeted by other sources as the demands increase. Do you see system storage decreasing or at lest an increase in the flow out of tanks when the other WTP is offline? While Tanks have a limited supply, they can act as a water source until they run dry. If they have a head higher than the set HGL of the WTP they will supply water temporarily until the water level get's low enough that more water would come from the WTP.

If you run a quick mass balance with both conditions to calculate the water supplied from each tank and reservoir, this will confirm where the water is coming from. With the one WTP out, you may have to increase the other WTP discharge HGL to compensate in order to fill the system water tanks.

Patrick Moore