Downstream Tracing

[NadiaAlami]

Hi, we try downstream tracing using our waterpipe line data, and we confused with  the results.

For example, if we put the start point at the main pipe in  the result is as shown in figure below. Its look like it trace the entire area. 

However, when we trace in smaller area(for example we put the starting point at the residential area, the result as shown below. it looks like inconsistent output or actually the result is correct?

[MikeMillerGIS]

My guess is that you checked "allow_indeterminate_flow" checked

https://pro.arcgis.com/en/pro-app/latest/tool-reference/utility-networks/trace.htm#GUID-72D79FCF-DEA...

[RobertKrisher]

@NadiaAlami Water distributions tend to be designed and built to include a lot of redundancy, which results in much of the network being looped (i.e. indeterminate flow). This means that water can potentially flow in either direction of a pipe depending on the time of day and active water sources. When a downstream trace or upstream trace encounters indeterminate flow it will include all the features in the loop because the trace could take either direction to satisfy both the upstream or downstream trace.

[NadiaAlami]

Hi RobertKrisher,

tq so much for the explanation. 
May i asked one more question, what is the best tracing method for condition like pipe burst or broken pipe that happen at water main pipe or big area and in the same time we want to know which service connection will affected.

[RobertKrisher]

@NadiaAlami Isolation trace. You'll set a filter barrier for the criteria you want to use to identify your isolation equipment. This is typically looking for features with a category of isolating, but can also include criteria like it must be operable.

[NadiaAlami]

@RobertKrisher  okay lets say my situation is pipe burst and valves with be closed. The affected assets will include likes fire hydrants, service connection, storage and etc., can you suggest how can we trace this using the isolation trace method and what can we put in the filter barrier? 
thank you in advances..

[RobertKrisher · Accepted solution]

@NadiaAlami all the system valves in the model have the isolating category assigned to them. You'd use the advice I gave above which is to set a filter barrier for the category of isolating. If you were worried about whether the valves were accessible or operable (and you maintained such attribution) you could also include those in your filter barrier.

[MichaelParma]

Adding to what Robert said, also be sure to check the "include isolated features" option on the isolation trace to return your hydrants, service connections, storage, etc.

-Mike