Time step control features includes options for defining simulation period and time step amongst other parameters for the different modules.
Any constant time step can be used in the simulation. Note that the temporal resolution of the input time series can be with any variable temporal resolution different from the simulation time step. Depending on the value type of the time series different interpolation method is used. For more details, see 2.5 Creating Input Files (p. 34).
Note that if the monthly time step is selected, the time step length must be one month, i.e. it is not possible to select a 2 or 3-month time steps.
The results will be written for every time step. However in order to reduce the size of the result file without compromising the accuracy of the computation it is possible to choose a time step sub multiplier. Each time step will be divided by equal sub time step for computing the results, however the results will be written at the end of every time step. For example, if the time step is 1 day, and the time step multiplier is 4, then the computation will be performed every 6 hours, and the results will be written daily.
It is possible to run a simulation with the Basin module in a simple stochastic type of mode, where the initial conditions are reset every year. This is convenient if you want to analyse e.g. drought management scenario for a number of months in the future for likely climatic/inflow conditions. Running in the stochastic mode for say a 20 years period, a 20 years output file of e.g. water level will be produced. It can be interpreted as running 20 times one-year simulations using the same initial condition, but for different inflows and climatic conditions.
If reservoir sedimentation is included in the Basin simulation (cf. Section 4.1.1), the frequency at which the level area volume (LAV) curve is updated (number of time steps between updates) must be specified.
Rainfall runoff time step length
If Rainfall-runoff has been enabled in the Modules part of Simulation specification (cf. Section 4.1.1), the time step length to be used by the Rainfall-runoff model must be specified.
