Time Step Options

The Time Steps page establishes the length of the time steps used for runoff computation, routing computation and results reporting. Time steps are specified in days and hours:  minutes: seconds except for flow routing which is entered as decimal seconds. The input parameters are:

Reporting Time Step: allows the user to set the time interval for reporting of computed results. 

Runoff - Wet Weather Time Step: allows to set the time step length used to compute runoff from subcatchments during periods of rainfall or when ponded water still remains on the surface.

Runoff - Dry Weather Time Step: allows to set the time step length used for runoff computations (consisting essentially of pollutant buildup) during periods when there is no rainfall and no ponded water. This must be greater or equal to the Wet Weather time step.

Routing Time Step: allows the user to set the time step length in seconds used for routing flows and water quality constituents through the conveyance system. Note that Dynamic Wave routing requires a much smaller time step than the other methods of flow routing.