Hello,
I am currently using InRoads (S&S) (.stb) to model storm drains. I have a concrete barrier wall as a median and grated drop inlets on either side so I can be said to have an "infinitely" high curb height because the water will never be taller than my median. I have place multiple grate inlets on grade leading up to my sump inlet and the on grade inlets have a spread onto the road in the ball park of 9-11 feet. Using a different program I know that I should expect a spread in the ballpark of 12 feet for the upcoming sump inlet. I know that I have an orifice condition so I set the orifice height at .02 feet because I always want orifice equations to be used but when I do this it produces a spread of 1 foot for the sump inlet which is not correct. When I set an orifice height of 6" or higher, it uses the weir equations and gives a spread of about 6 feet which is still not correct.
MicroStation V8i (Selectseries 2) - Version 08.11.07.443
Bentley InRoads V8i (Select Series 2) - V08.11.07.615
Can you post an SDB for us to test (and give the inlet ID)? I took a quick look at my HEC-22 2nd Ed. to see how the depth should be calculated for sag inlets and found an example (Example 4-14) for Combination inlets where they used equation 4-26 to solve for the depth above the inlet. I suspect the program is doing something similar, but want to check it with your data.
I have made some changes to my clogging which lowered my spread to about half, but I am still expecting quite a bit more spread than it is giving me on the two inlets that are in sump. The ID's are 1175+70 LT. and 1181+50 RT.
I would also encourage you to look at example 4-14 on page 4-67 where depth and spread are calculated for a combination inlet. It seems to confirm the method S&S is using.
If you disagree, please feel free to provide the equations and workflow you would like the program to use, and I can file a change request to consider adding a new method.
I do not have a combination inlet. I have one up against a barrier wall like shown below.
Also to add to this conversation. I am needing to know if there is an area in this program where it will give me a report on the pipes that are not meeting the minimum cover I am specifying. I am also needing to know how to attach an inlet to the top of a box culvert. When I have attempted this, it states that the box culvert is not valid for this.
The command used to check pipe cover is Evaluation>Profile>Check Pipe Cover.
In order to attach an inlet to a culvert, first make sure your Drainage Options are set to place a "Median Drop" inlet. This is the only type that will attach to a culvert. Then, when you use Drainage>Layout>Inlet, make sure the "Connect to Existing Structure" is toggled on.
Answer Verified By: Anna Troutman
What I will actual be attaching will be considered a manhole above the box culverts not an inlet because it will not be taking in any water from the top, just from a pipe connected to it.