Dear Bentley Community
I'm drawing a WDS for a state park using the latest version of WaterCAD. One pipe is connected to the nearest city and there is pressure of 30 psi at the connection.
What should I use to mimic this city connection so that I can set
- Water Flow in gpm from the City
-Water Pressure of 30 psi
Should I use tank, reservoir, or something else in this case?
Thank you.
Yoko
Yoko,
You should specify a known hydraulic grade at a reservoir (based on the pressure) or a known inflow at a junction but not both.
You need to ask yourself which property you will know for a given scenario. Sure the pressure at the connection my be 30 psi today but will it always be at that value, even during the worst case scenarios you may be simulating.
Remember also that you need at least one tank or reservoir in your model to set the HGL.
There are some other methods we recommend if the pressure at the connection point various with flow. In that case you would base a pressure (HGL) vs. flow graph on the results of a hydrant flow test at the connect. See our Advance Water Distribution Modeling and Management book for guidance on that.
You need to undestand the strength of the distribution system on the city side of the connection. Talk with the engineers from the city and see what their model says.
Tom
Tom,
Thank you so much for your thorough answer.
It's very helpful.
I've attached a paper we have that goes into a bit more detail on the subject of modeling a connection to an existing system. This will be documented in our wiki soon.
Regards,
Jesse DringoliTechnical Support Manager, OpenFlowsBentley Communities Site AdministratorBentley Systems, Inc.