How to initialize a groundwater prequel
Initial configurations for the complete groundwater model of the Water Overlay often do not represent the state 'at rest'. Consequently, groundwater typically flows toward a more stable configuration during the simulation's initial period. For example, an initial groundwater dataset may have a consistent groundwater level defined for a large plot of land, while the more natural situation may be that the water follows a curve due to the way water flows into and out of the ground.
In short simulations, groundwater may not reach a natural state before the main event or simulation end. To compensate, run a stationary calculation first to allow the groundwater to settle, then use this stable result as the initial state.
This can also be achieved in a dynamic setup in which the calculation for initialization is set up as a "prequel", an explicit precursor calculation to the actual simulation.
- Add a Groundwater Overlay to initialize the groundwater level before the actual simulation.
- Ensure that the Groundwater Overlay has the groundwater mode set to "Complete".
- Ensure that the Groundwater Overlay has data for groundwater set, if one is available.
- Ensure that the Groundwater Overlay has a ground last value output.
- Configure the rainfall for the model to run stationary, for a period of multiple weeks.
- Recalculate the Groundwater Overlay.
- Add a second Groundwater Overlay, which will use the first Groundwater Overlay's results as input.
- Open the second Groundwater Overlay's Water Overlay configuration wizard, and proceed to the groundwater step.
- Select the option "Select a Groundwater Depth Grid Overlay".
- Select the first Ground Water Overlay as prequel.