C.5 Events Editor

The Events Editor is activated when the Events sub-category of simulation Options is selected for editing from the GeoSWMM model object panel.

It is used to limit the periods of time in which a full unsteady hydraulic analysis of the drainage network is performed. For times outside of these periods, the hydraulic state of the network stays the same as it was at the end of the previous hydraulic event.  Although hydraulic calculations are restricted to these pre-defined event periods, a full accounting of the system's hydrology is still computed over the entire simulation duration. During inter-event periods any inflows to the network, from runoff, groundwater flow, dry weather flow, etc., are ignored. The purpose of only computing hydraulics for time periods is to speed up long-term continuous simulations where one knows in advance which periods of time (such as representative or critical storm events) are of most interest.

 The dialog consists of a table listing the start and end date of each event, plus a blank line at the end of the list used for adding a new event. The events do not have to be entered in chronological order. There are date and time selection controls below the table used to edit the dates of a selected event. Clicking the Replace Event button will replace the row with the entries in these controls. The Delete Event button will delete the selected event, and the Delete All button will delete all events from the table. The first column of the table contains a check box which determines if the event should be used in the analysis or not.

§  To identify event periods of interest, one can first run a simulation with Flow Routing turned off (from Simulation Options - General) and then perform a statistical frequency analysis on the system's rainfall record (see Viewing a Statistics Report).

§  When a new event occurs, the water in a storage unit node will remain at the same level it had at the end of the previous event. Therefore, one may want to choose event intervals long enough to minimize the effect that storage carryover might have.