Trace results with loops and double-outlet sewer structures

[NickHarvey]

Hello All - I have been tracing in a single-use Utility Network (Pro 2.8, 3.1 Sewer Asset Package applied to a fgdb).  I had applied condition barriers to our 'double-outlet, no inlet' sewer structures and it blocked unwanted tracing through those particular loops (example circled in green in the attached graphic).  However, I just discovered that in my UN this doesn't work for 'double-outlet, single inlet' structures (highlighted in yellow).  Tracing upstream and downstream of these loops (outside the loops) is fine.  But, if the trace is started anywhere within the loop that trace will continue throughout the loop against the digitized direction of the lines.  The network in the attached example graphic consists of one Treatment Plant device, Sewer Stormwater Vaults, & Sewer Gravity Mains (plus one Condition Barrier).  The red lines indicate unwanted trace results from an upstream trace that was started within the the loop.  This is a significant problem for us because we have some very long dual interceptor lines that braid and combine downstream, etc.

Would really appreciate any help, just getting started with the UN.  Hoping to learn and eventually get this is running in our Enterprise environment.   

-Nick

[NickHarvey]

Man, its tough when everyone replies at once.  I did find a Note regarding this on the Utility Network trace types page:

Can anyone on the ESRI UN Team suggest a workaround? Or will directional loops be supported in the future?  Our braided (dual) interceptor lines cover dozens of river miles.  If we were storm water, this would be troublesome because tracing upstream of an illicit discharge sampling hit on one side of the loop would select the whole loop (upstream and downstream).  But the same goes for our wastewater allocation queries  (with a potential connection to one side of a dual interceptor). 

[JonDeRose]

@NickHarvey I'm glad that Alex was able to provide you with the solution.  This also highlighted an oversight in the documentation that should have been updated with the ArcGIS Pro 2.8 release.  We've made the change for the next release.  While the note still holds true when tracing through loops without directional devices, the updated note should read: 

"When loops are encountered during an upstream or downstream trace, trace results will return all features in a loop unless devices with a directional terminal configuration are present."

[NickHarvey]

Thanks Jon makes sense - and concise. 

[AlexKabak · Accepted solution]

Hi Nick,

A workaround is to create a directional terminal configuration with 1 upstream (Inlet) and 2 downstream (Outlet 1, Outlet 2). You will also want to create a separate manhole asset type (ex. Multiple Outlet Manhole) to assign the new terminal configuration, as you don't want to have to set terminals each time on a standard manhole. Assign the incoming main to the Inlet terminal, and the 2 outgoing mains to Outlet 1 and Outlet 2.

Please let me know if you need further assistance with this process.

- Alex

[NickHarvey]

I just got this working thanks Alex. I had seen this post regarding double-outlet manholes (We use the term 'double-outlet', as 'elevated' might invoke raised manholes at our agency).  I had thought it might be a solution but couldn't figure out how to create terminal configs, post-Topology.

So that brings me to this question:   I could not find a way to implement this solution without creating a new fgdb UN which are not auto-associated with the asset package data model (a number of steps to replace). Will terminal configs always be necessary to create, pre-Topology? Or, is there workflow that I'm missing or unaware of?  Knowing the answer will help me plan for our UN Enterprise deployment, your solution works in either event. 

Thanks a bunch!

-Nick

[NickHarvey]

Just discovered this post.  Using the UN Package Tools it looks like you can Apply Asset Package to a newly created UN inside a newly created fgdb and the schema/model is applied and will still allow you to create a new terminal configuration.