storm cad

Question

Hi, 
 1) Can you guys please tell me how to calculate flow (downstream)? This label is seen in conduit flex table. 
 2) Can we do automatic design for open channel flow of rectangular shape? 
 3) What is the average velocity? and how is it calculated? 
 4) Can anyone please tell how to calculate time of concentration for any catchment using excel? 
 
 thanks.

MPachlhofer · Accepted Answer

3) What is the average velocity? and how is it calculated? 
 communities.bentley.com/.../10356.what-are-the-different-velocity-methods-used-in-sewercad-and-stormcad.aspx

MPachlhofer · Answer

1) Can you guys please tell me how to calculate flow (downstream)? This label is seen in conduit flex table. 
 Are you talking about the Flow(Downstream Conduit) field? 
 Flow itself in StormCAD is determined by the system time. As the system time changes, the intensity change, which has a direct effet on the rate of flow in the system. Basically what StomCAD does is take the IDF curve that you have entered as for your storm event and look up duration then it can provide an intensity for that duration. 
 If you want to calculate the flow downstream in StormCAD you should have a look at the help document titled "System Time / Controlling Time / Duration ". This document explains how everything works together to determine the flow in a pipe and thus flow downstream

MPachlhofer · Answer

4) Can anyone please tell how to calculate time of concentration for any catchment using excel? 
 I think the best suggestion I have for this one is you'll have to Google it and have a look around unless anyone has another suggestion based on a formula they've used for estimating Tc. I used this search term "calculating time of concentration using excel" and got a few hits. looks like Tc can be estimated in slightly different ways depending on your location in the world or at least the US because I see examples that are specific to certain regions or states. That's just based on some inferences I'm making on what I am seeing though.

MPachlhofer · Answer

2) Can we do automatic design for open channel flow of rectangular shape? 
 I don't know that I've ever been asked this before. Based on what I know and what I'm seeing I'm going to say no, for the most part because the check box for "Available for Design?" in the conduit catalog is greyed out making it not an option for at least designing the size. This would lead me to believe that it also will not design the slope and the slope of the channel will be based on the slope up the best design for the upstream and downstream elements.