Weather (Water Overlay)
Weather for the Water Module is defined as a Weather data. defines a number of environmental circumstances the hydrological model is subject to. It also defines the (total) simulation time.
Weather is a required connection. There is always exactly one weather connected to a water overlay, and by default if no weather exists an appropriate weather effect is created and connected automatically.
Rain
Rain is a consistent addition of water to the hydrological model over a specified period of time. At the end of the rainfall's duration, the specified amount of rain will have fallen in each location in the project. The simulation can calculate both periods of rain as well as dry periods.
The total simulation time is composed of both the periods of rain, and the dry periods. It is possible to set up a simple, linear rainfall situation, in which a period of consistent rain is followed by a dry period. More complicated, custom configurations can be loaded in as well.
During a period of rain, the rainfall is constant. In each timestep an equal amount of water will fall, such that by the end of the period of rain that exact of rain will have fallen.
Simulation time
Evaporation
Evaporation is the consistent removal of water from the hydrological model over a specified period of time. As long as evaporation takes places at a certain rate, water both on the surface and underground can be subject to removal from the hydrological model. The evaporation rate defined by the weather is the base amount of all types of evaporation in the calculation.