Can anyone please explain about these two different errors as shown in the screen capture.
The user notification in the image you provided references catch basins that don't have subsurface elements attached to them. When flow enters a catch basin it will then be subsurface flow. If a conduit is connected to the catch basin, then it can convey that subsurface flow. Without the conduit attached, the subsurface flow will have nowhere to go. This is why the message states that the captured subsurface flows are lost.
Bentley Technical Support
If there are conduits attached to these catch basins, they will need to connect to an outfall to be "valid".
Make sure there aren't any overlapping nodes that create a disconnection in the network.
You can use Network Navigator to locate elements that are disconnected from the outfall.
To do this:
1. Go to View > Navigator
2. Click the ">" icon > Network Trace > Find Disconnected
3. For the "Find Elements Disconnected From" input field, choose "Select..." > click on the outfall element > Click OK.
4. The Network Navigator dialog will then list all elements that are disconnected from that outfall.
5. Click the highlight icon in the Network Navigator dialog to highlight all of the returned elements.
This should make it easy to locate where the disconnection is in the model.
The Network Navigator, Network Review query "Orphaned Nodes" may help as well.
The following article was written for the different products, but it does a good job at explaining how to use the tool and includes a video demonstration.
Using Network Navigator
There are no red user notifications and the results converge, so the setup should work. You have notifications related to lost subsurface flow, but these are for the catch basins that are set up to have a very little captured flow, so that is expected.
The high spread values appear to be for the gutters where there is little captured flow, so this is not a surprise as well. I checked FlowMaster for one of the gutters (GU-3) and it appears have similar results compared to StormCAD. Was there a certain gutter you checked that was different?
As for the automated design results, StormCAD uses a set of design priorities. The order of these cannot be changed by the users. It is possible that a lower priority is violated to keep a higher priority item from being violated.
Applying changes manually is often required after running the automated design. As noted in the Help topic "Design Considerations":
"As with any automated design, the program's design is intended only as a preliminary step. It will select pipe sizes and pipe invert elevations based on the input provided, but no computer program can match the skills that an experienced engineer has. The modeler should always review any automated design, and should make any changes required to adjust, improve, and otherwise polish the system."
While you can run the design again, that will be up to your engineering judgment. If you are happy with your adjustments to the automated design run, performing an analysis should be sufficient.
If there is only one catchment area for both inlet and gutter where should I assign my catchment area to calculate the spread at the upstream of the downstream inlet.
You mentioned the spread results are similar from stormCAD and Flowmaster for GU-3, but I did not found such.The results are in 6 ft difference though the inputs are same.
Please review my model one more time and help me out.
The 9.42 discharge is from IN 6-1 and flow from gutter 3 (8.46+0.96).