Time Series files are external text files that contain data for SWMM's time series objects. Examples of time series data include rainfall, evaporation, inflows to nodes of the drainage system, and water stage at outfall boundary nodes. Normally the data is entered and edited through SWMM's Time Series Editor. However, there is an option to import data from an external file into the editor. Creating and editing this file can be done outside of SWMM, using text editors or spreadsheet programs.
The format of a time series file consists of two lines of descriptive text, followed by the actual time series data with one time series value per line. Typically, the first text line identifies the time series and the second line includes a detailed description of the time series. Time series values can either be in date/time/value format, or in time/value format where each entry is separated by one or more spaces or tab characters. For the date/time/value format, dates are entered as month/day/year - e.g. 7/21/2004 - and times as 24-hour military time e.g. 8:30 pm is 20:30. After the first date, additional dates need only be entered whenever a new day occurs. For the time/value format, time can either be decimal hours or military time since the start of a simulation e.g. 2 days, 4 hours and 20 minutes can be entered as either 52.333 or 52:20. An example of a time series file is shown below:
EPASWMM Time Series Data
<optional description goes here>
07/01/2003 00:00 0.00000
00:15 0.03200
00:30 0.04800
00:45 0.02400
01:00 0.0100
07/06/2003 14:30 0.05100
14:45 0.04800
15:00 0.03000
18:15 0.01000
18:30 0.00800
When preparing rainfall time series files, it is only necessary to enter periods with non-zero rainfall amounts. SWMM interprets the rainfall value as a constant value lasting over the recording interval specified for the rain gauge, which utilises the time series. For all other types of time series, SWMM uses interpolation to estimate values at times that fall in between the recorded values.