Posted Thu, 20 Jul 2017 20:14:50 GMT by Liaqat Khan
I would like to represent a leaping weir in MIKE URBAN to correctly simulate flow split at node with one influent and two effluent pipes. The inflow goes to dry weather pipe (DW-Pipe) and wet weather pipe (WW-Pipe) as shown in the enclosed figure. I am looking for suggestions and, if possible, an example model setup that I can follow.
Liaqat Khan   
Posted Wed, 02 Aug 2017 13:58:56 GMT by Brian Brenhaug Enterprise Water Systems Team Manager
Hello Liaqat,

I'm not too familiar with a leaping weir configuration, but if it is similar to Figure 8-3 in the blog article below, I would model it as a
[li]small orifice element representing the "diversion to interceptor" connecting to the dry weather effluent pipe[/li]
[li]weir element representing the "transverse weir" connecting to the wet weather effluent pipe[/li]
I'd put the small orifice at a lower elevation than the weir crest elevation. Assuming the leaping weir (below) is what you're aiming for, this modeling method would result in some small erroneous flow into the dry weather pipe (probably minimal compared to the size of the wet weather flow).

From your graph, I'm guessing the dry weather pipeline intake must be located strategically so that the water jumps over the intake at high flows, like in the blog post below. I don't believe such momentum-based characteristics of the water flow work so well in the simplified hydraulic modeling world...super-elevation is a similar effect that requires a more advanced modeling engine if you absolutely need to model it. Assuming you have the RTC module, you could force the diversion using MOUSE's RTC to set controls on either some valve elements, gate elements, or a weir height above a certain flow or above a certain level. This strategy would be fairly cumbersome and probably require quite a bit of iteration. You'd also need to add rules to the RTC to "reset" the configuration of everything back to dry weather conditions.

If you don't have RTC, there may be a way to force the diversion to happen using passive controls in the link elements.

This is all assuming you're using MOUSE...if you're using SWMM I'd probably use some of the strategies in the referenced blog links above.

Hope that helps a little.

Posted Wed, 02 Aug 2017 14:36:13 GMT by Liaqat Khan
Hello Brian,
Thank you for your suggestions. I have seen the blogs listed in your response and, for now, implemented a simplified version in MIKE URBAN. I was hoping to find a simpler approach to enforcing flow split at leaping weirs.
Thanks again,

Liaqat Khan

You must be signed in to post in this forum.