1000 Year Simulation with Rainfall in SWMM 5

Subject:   1000 Year Simulation with Rainfall

The attached one Subcatchment SWMM 5 model and associated Rainfall was created using the Random function in Excel on a measured NCD station in Boston.    There is a dry weather flow component of 0.5 cfs with an hourly pattern.  The rainfall averages 54 inches over the 1000 years and the runoff is 20 inches on average over the 1000 years.

Figure 1. Combined Flow at the Outfall for the 1000 year Simulation.

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  • You can use the SWMM 5 Statistical Tool to compute the return period  Q1000, Q500, Q100 and Q50 flows for the 1000 year record


  • I see the issue, that is a newer formatted NWS rainfall file that has to be edited.  Let me see what has to be done to make is usable for you.

  • I got it to work on a different project file.  I think the file I had was incomplete.  I am having problems importing rainfile data.  I am new to this so I need to know the basics.  Here is the rainfile I am trying to import.  See attached

  • Still didn't work

    • It does not have a time series named TS1 or any time series for that matter3293134041?profile=original


  • Hi, Did you use it as an external time series file and what version of SWMM 5 are you using?

    • Build 5.0.022.

      I imported as an external time series file.

      • Hi, I just downloaded it again and it ran after I reattached the dat file to the Rain Gage object


  • i inputed this rainfall data to my project but I get this error:


    ERROR 173: Time Series TS1 has its data out of sequence



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