"Intertie" feature class and network modelling?

JoeBryant2

Hi water people,

I'm wondering if anyone using the LGIM schema and/or geometric networks has added an additional feature class or subtype to model "interties" with surrounding water districts. 

Although we are not yet using them, we have a number of connections with surrounding water districts on our boundary. The Regional Water Authority is requesting that we start modelling their use in the future, both delivering and consuming water. Currently I have these points as a separate feature class representing the tie-in location; the physical valves and fittings that would connect the systems are in their expected feature classes. We would obviously install meters at these interties, but I'm not sure if they would make sense to put in the wServiceConnection feature class, as those are located at the end of laterals. There would obviously be separate meters for delivery versus consumption. 

I'm also thinking about how these will be assigned as possible "sources" in the geometric/utility network. There may be pumps installed, but that is not currently part of the plan - we are just looking at available pressure/volume at each connection. And if a connection would actually be used as a "sink", will we be able to model that (having both sources and sinks is not recommended)?

Maybe something to consider adding to a future LGIM update with the Utility Network?

RyanKirkham

Joe,

I work at the City of Sacramento, Dept of Utilities and we just completed our LGIM migration this past week.  It's taken over a year to plan and test, but we're finally done.  The intertie/turnout discussion came up quite a bit during our migration but it was never really addressed since it was a lower priority compared to the rest of our transmission and distribution system.  We are now getting started on the second phase of our implementation, which is to develop and build up other feature classes that didn't make it into our first phase.  This is going to include interties, cathodic protection and backflow prevention assemblies.  Currently we are planning to have an intertie feature class, with subtypes for emergency connections and wholesale connections.  The emergency connections are basically just a valve that remains closed most of the time and the wholesale connections are more of a mini facility with SCADA, metering, pumps etc.  Sounds like we're both in kind of the same spot so if you or anyone else has tips/tricks/advice for how to deal with these issues I'd love to hear what others are doing too.  As for your question about the source vs. sink issue, I took the Geometric Networking class a month or two ago and I asked the exact same question.  Based on the feedback, the instructor indicated that having both would be OK.  That answer was a little surprising since I've heard the same statement in the past that it isn't advisable to have both in your network.  Any clarification from ESRI would be helpful.  Anyways, feel free to contact me if you'd like to collaborate on some of this.  We're in the same vicinity so I know we're dealing with most of the same issues.

Ryan