Ventana software support forum

hi all
I am doing rainfall-runoff model very simple. I just need a hand on one issue. I have some paramter as level with initial value. I need the model read the initial vlaues at time step zero but start the calculation for all other variables at time step 1.
Any help how i can do this.

Hi Amgad

Your question is not very clear.
First a parameter cannot be a level, but eventually the starting value of the level.
Secondly, if the auxiliary variables are or are not calculated does not make any difference, as long as their value is only depending from the value of the past level. I think that you may want to keep the value of the levels unchanged until a defined moment, in this case time 1.
In that case, you have to zero all the rates if the time is less than 1. It can be easily programmed:
Rate = if then else (Time < 1,0,normal value)
What is the time step of your model?
You can eventually post a simplified model illustrating your problem.
Regards.
JJ

If you want to use an initial value from time 0 for 1 level but start everything else at time 1 then start the model at time 1 and initialize the level with the formula

initial constant + rate of change at time zero * TIME STEP

Of course, i am not sure that is what you meant either.