Rain model (Water Overlay)

Rain can be implicitly activated and deactivated by defining an appropriate period of rainfall as weather effect. If a period with no rainfall is defined, that period is simulated but no rain is simulated.

Currently, during a period in the simulation where rainfall is defined, water is uniformly added to the surface of all cells in the project area. During any single defined period of rain, the amount of rain is consistent over time. At the end of the defined period of rain, exactly the defined amount of rain will have fallen on each cell.

It is possible to add up to 50 consecutive rain periods. It will look something like:

Time key (minutes)	Amount of rainfall (mm/m2)
35	15
42	19
120	5

This format can be interpreted as followed:
The first period is starts at t=0 minutes and ends at t = 35 minutes. In this first period, 15 mm/m² of rain will fall. Uniformly this gives 15 / ((35 - 0) * 60) = 0.00714 mm per second.
The second period starts at t=35 minutes and ends at t = 42 minutes. In this period, 19 mm/m² of rain will fall. Uniformly this is 19 / ((42 - 35) * 60) = 0.04524 mm rain per second.
The last period starts at t=42 minutes and ends at t = 120 minutes. In this period, 5 mm/m² of rain will fall. Uniformly this is 5 / ((120 - 42) * 60) = 0,00107 mm rain per second.
In total it can be expected that per m² 15 + 19 + 5 = 39 mm rain has fallen. Template:WaterOverlay nav