Groundwater Prequel (Water Overlay)
Groundwater levels in the Water model can be initialized using a Overlay Prequel.
Values in the groundwater Prequel can represent either:
- the datum height of the ground water level.
- the water depth, as the initial distance between the surface and the watertable. A greater value in the GeoTIFF will result in a lower watertable.
When a groundwater Prequel is not configured for the Water Overlay, the watertable is initialized using the WATER_LEVEL attribute of the water area instead (or the Water Level Prequel, if so configured). For locations without water areas, the water table is set to one meter below the surface.
The following Prequels are possible:
|Name||Prequel||Underlying data||Unit||Description||Range||No data|
|Groundwater datum||GROUND_WATER_DATUM||Water Prequel||Used for initializing the ground water level on this datum.|
|Groundwater depth||GROUND_WATER_DEPTH||Water Prequel||Used for initializing the ground water level to these depths.|
|Unsaturated fraction||UNSATURATED_FRACTION||Water Prequel||Used for initializing the saturation of the unsaturated zone in the underground.||0 to 1||Clamped to range|
For the Netherlands, a number of groundwater GeoTIFFs are provided by default, based on data provided by The Netherlands Hydrological Instrumentarium:
- NL_GHG_kk-nhi (Average highest waterdepth)
- NL_GLG_kk-nhi (Average lowest waterdepth)
- NL_GVG_kk-nhi (Average spring waterdepth)
It is important to emphasize that when using these GeoTIFFs, they should be configured as water depth (relative to terrain) rather than water height (relative to datum).
- How to use a default groundwater GeoTIFF (Water Overlay)
- How to upload and use a groundwater GeoTIFF (Water Overlay)
- Water area (Water Overlay)
- Underground model (Water Overlay)
- Ground watertable result type (Water Overlay)