Upstream or middle Gutter Nodes simulation where no Catch basin needed

Question

Hi, which element should I use to model a superficial network of gutters and only when the capacity of those gutters are exceeded I include a Catch basin?

Imagine there is a long street (on grade) and there are some catchments that contribute along the gutter or small channel, there is a length where the section is enough to transport the flow and the catchments are connected to a nodes (not catch basins), only when the capacity of the gutter/channel is exceeded or 90% for example I include a catch basin.

I've tried with gutters but the upstream node or middle nodes have to be catch basins, first I don't need to catch any flow and second I don't need to include a pipe (conduit) out of every catch basin.

I've tried too with channels, but the nodes are "cross sections elements", the sections to model are limited (only trapezoidal and irregular), when I include the catch basin the invert of the channel is connected to the invert of the CB and not to the rim.

I think I've been using the wrong element to simulate my case, please let me know how to do it.

Thanks

Jesse Dringoli · Accepted Answer

Hello Ricky, 
 Regarding #1 - correct, with the GVF Rational solver, when a channel is connected to a catchbasin, flow from the channel will be interpreted as sub-surface (as opposed to approaching the inlet opening.). 
 Regarding #2 - correct, bypass flow from a catchbasin inlet must be conveyed downstream in a gutter link element. 
 Regarding #3 - technically a cross section is a permissible upstream element for a gutter though I do not believe this is what you need in this situation. 
 Regarding "the flow out of the outfall is less than the flow that arrives in the channel." - most likely the reduction in flow you see is due to an increase in the system flow time. When the GVF Rational solver re-computes the rational method equation (Q=CIA) at the end of the channel, the increase in the system flow time results in a lower intensity and lower flow. See more in this wiki article: 
 Why does flow or velocity sometimes decrease when moving downstream? 
 I'm not entirely clear on what you are trying to accomplish but it sounds like you do not yet know what size inlets to use and/or where or how many to place and would like to see the gutter depth and spread first. 
 You may want to consult with any local standards on inlet placement, use an initial guess and check the results. Or, populate the inlet catalog with standard inlet sizes and opening lengths and let the automated design feature size the inlet openings to meet depth/spread requirements. 
 If you must lay out the gutters only without "real" inlets, you could try inserting catchbasin elements with Inlet Type set to Maximum Capacity and the maximum flow set to something very small like 0.01 L/s. 
 Note that starting with V8i SELECTseries 3, the GVF Rational solver in CivilStorm can compute surface inlet and gutter results without having to lay out sub-surface network conduits and outfalls. See "Inlet only hydraulics in this article: 
 What's New in SewerGEMS and CivilStorm V8i SELECTSeries 4

Jesse Dringoli · Answer

Hello Ricky, I have sent you a private message regarding #2. The workaround is to use two separate outfall nodes, or insert an intermediate manhole or transition node in each of the adjacent conduits. 
 Related Defect: #618841

Sushma Choure · Answer

Hello Ricky, 
 Which software are you using? 
 Channels, cross sections and the catch basins are best suited for your case. Please note that channels and cross sections cannot be designed they can only be analyzed. 
 About the invert levels of the channels, if you don't want the invert levels of the channels to connect to the catch basin invert levels then you can specify "Set Invert to stop " to FALSE and specify the required invert level of the channel stop node as required.

Craig Calvin · Answer

Hello Ricky, 
 The catch basin symbol can't be edited in standalone. You can edit the catch basin cell that is used when integrated with MicroStation, but it would apply to all catch basins. To visually differentiate between the two catch basins, I recommend using element symbology (annotations and/or color coding). 
 To do this: 
 
 Open element symbology manager. 
 Right-click on Catch Basin > New > Color Coding 
 Set Field Name to Inlet Type 
 Click the Initialize icon. 
 You can edit the values and assigned colors. 
 Click OK 
 
 See the following article for more information. 
 How do you add color coding or annotation to an element?

Sushma Choure · Answer

Hello Ricky, 
 
1. The Flow/Capacity (design) is not available for gutters, but if you have say user defined section for the gutters, software does calculate the depth/rise ration which might be helpful for you.

Scott Kampa · Answer

Hello Ricky, 
 
2. I tested this is a sample and the results at the outfall were the combined flow results from the two conduits connected to the outfall. I would review your model and your results to assure everything is set up correctly. If the model is set up correctly, we will likely need to see a copy of the model to look into this. 
 
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If you upload the model to Sharefile, post here with the name of the file so that we know it is available. 
 
3. If you have details on the size of the grate, you could include this in the engineering library. The general steps to edit and add to the engineering library can be found here: communities.bentley.com/.../7478.modifying-and-adding-entries-to-engineering-libraries . Otherwise, you may need to adjust the size of the grate to account for the different size. 
 
Regards, 
Scott