Calculation preference formula (Water Overlay)
These settings influence the timesteps for rain, surfaceflow and groundwater in the calculation model. All settings result in stable solution, however small fluctuations can occur in the hydro-graphs. By default Speed is selected, only change this when your use-case demands it.
- Speed: Larger timesteps.
- Normal: Average mode between speed an accuracy.
- Accuracy: Smallest timesteps.
Low Impulse Mode (fast)
By default the model uses full impulse to simulate waterflow. However when using long term average calculations (e.g. groundwater year round) the impulse has a very limited effect on the outcome. You can then select the Low Impulse Mode option which reduces gravity in your simulation and thus the impulse. This means that peak velocity in heaver rain-showers or floodings are not accurate, but the average waterflow through the system remains the same.