Export and Analyze in Storm and Sanitary Analysis (10:09 min)

The Storm Drainage design of any project can be the most important aspect. In this section, we will be looking at exporting and analyzing a storm drain system with the Autodesk Storm and Sanitary Analysis (SSA).

SSA is a comprehensive hydrology and hydraulic analysis application. It helps you plan and design urban drainage systems, storm sewers (including highway drainage systems) and sanitary sewers. It also integrates stormwater and wastewater analysis during planning and design, which helps you improve overall project productivity and increase your engineering capabilities.

By the end of this session, you’ll be able to export to SSA and run a storm drain analysis.

First, we must export the file. There are several ways to do this:

1. In Civil 3D, select the “Analyze” tab from the top of the screen and select “Edit in Storm and Sanitary Analysis” in the “Design” panel.

2. Or, select any part of the pipe network.

3. Select “Edit in Storm and Sanitary Analysis” in the ribbon.

4. Once you select that, a window titled “Export to Storm Sewers” will appear. Hit “OK”.

This will open up the project in Storm and Sanitary Analysis as well as bring in your CAD file as a background.

5. Select “Create new project” and select “OK”.

6. This will bring up a log file of everything imported. It will ask if you want to save the log file, select “No”.

7. Close the “Log File” tab.

8. In the “Plan View” tab, you’ll be able to see the imported pipe structures and sub-bases.

Let’s look at the SSA options we can use to perform a proper analysis:

9. Select the “Input” tab and choose “Project Options”.

10. Here we will see the hydrology method of the project as well as other settings. For this example, change the “Hydrology method” to “SCS TR-55” and select “OK”.

11. Next, we want to look at the rain gage. Select “Rain Gage” from the “Plan View” panel on the left.

12. In the window that appears, we’ll see there is no rain gage assigned. Select “Add”.

13. Under “Rain characteristics”, change the “Rain data format type” to “Intensity”.

14. Under “Data source”, select a “Time series” by clicking on the “…” icon next to the drop-down menu.

15. A window titled “Times Series” will appear. Select “Add” in the top right of the window.

16. From here, you can key in the information on the left or select “Rainfall Designer…”.

17. In “Rainfall Designer”, choose your state, county, return period and “Unit intensity”. Hit “OK” and then “Close”.

18. Now, we want to assign the rain gage. Select “Assign” and assign the gage to all sub-basins, click “OK” and then close the window.

At this point, we’ve got our sub-basins and rain gages set up.

19. At any point, you can select and change your inlets to a different type of junction by right-clicking on it and selecting “Convert to” and then choosing the new type of inlet.

20. Remove any outfalls on the site, except for the outfall leading into the pond.

21. Next, double-click on one of your inlets. A window will appear asking what type of inlet we need. In our example, we’re going to select “FHWA HEC-22 Generic”.

22. For “Inlet Location”, select “On Sag” and click “Close”.

23. Repeat steps 19 – 21 for the rest of the inlets. You’ll notice there is still no analysis summary for the inlets. This is the next step.

24. Save the project. It will save as an SPF file.

25. Under the “Analysis” tab, let’s look at the analysis options.

26. In the window that appears, select the “Storm Selection” tab. Here you can choose a storm.

27. Select “Use assigned rain gage(s)”. you have the option to use multiple storms, but, for this example, we’re going to just use the assigned rain gage.

28. Select “OK”.

29. Run the analysis by selecting the “Perform Analysis” icon at the top of the screen.

30. After running the analysis, it will let you know if the analysis was successful or not. If it was not successful, select “OK”. A new tab will open and let you know what the error was and how to fix it.

31. Now, back to the “Plan View” tab. We want to see the network in a profile. Right-click on the starting inlet and select “Start Profile Plot”.

32. Then select the outfall and then click “Show Plot” from the “Profile Plot” panel on the left.

33. This will bring up your profile. The blue lines indicate HGL’s.

34. Now you can start analyzing your pipe network. If you return to your “Plan View”, double-click on the first inlet and key in values you’d like to analyze. For this example, we are going to flood our pipe by selecting the “…” icon next to the “External inflows” drop-down menu and keying in “15” for the “Baseline Inflow”.

35. Return to the “Profile Plot” and analyze it. You’ll see that the pipe is now flooded. If you return to the “Plan View” and hover over or double-click on the pipes, you’ll see the analysis summary.

36. In a case like this, where the pipe becomes flooded during an analysis, we can change the pipe diameter in SSA. Double-click on the pipe again in “Plan View” or “Profile Plot” and change the diameter in the top right of the window.

There are many simple things to analyze in SSA, making it easier to design the kind of pipe network you need for your project.