Stormwater Management Model (SWMM) Information for watershed water quality, hydrology and hydraulics modelers (Note this Blog is not associated with the EPA). You will find Blog Posts and Twitter Embeds on the Subjects of SWMM5, InfoSWMM, InfoSewer, SWMMLive, InfoSWMM SUSTAIN, SWMM4 and SWMM in general.
Weather Underground is a site that provides excellent local weather information in the form of graphs, tables and csv files. You can use the data very easily in SWMM 5 by copying from Excel to a time series in SWMM 5.
The data imported from the csv file to Excel and after the text to columns tool is used looks like this in Excel. The data is now ready to be imported into SWMM 5 after the time column is adjusted to fall on even 5 minute intervals. In Excel you can use the formula @ROUND((B2)/"0:05:00",0)*"0:05:00" to round all of the time values to 5 minutes. If you do not do this step then you will have problems in SWMM 5 due to the rainfall interval not being equal to the defined raingage interval.
Open up and make a new time series in SWMM 5 and then copy and paste the date, rounded time column and rainfall column into the SWMM 5 time series.
The solution is iterative but each iteration is dependent on the CFL or explicit time step. The time step we select is based on the CFL condition but instead of just using the explicit solution we iterate until the node depths are converged or a maximum of 4 iterations is reached. The solution of node depths and link flows in SWMM 5 is an iterative process but the number of iterations for the flows and links depends on how fast the node depth converges. The node continuity equation is ALWAYS solved at each iteration for each node but depending on whether both the link upstream and downstream node depths have converged the the number of iterations for a link may be between 2 and 4. The minimum number of iterations for a link is 2.