Groundwater Prequel (Water Overlay)

From Tygron Support wiki
Jump to navigation Jump to search

Groundwater levels in the Water model can be initialized using a Overlay Prequel.

Groundwater is only used when the GROUND WATER attribute of the Water Overlay is set to complete, meaning the ground model is vertically and horizontally fully active.

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 Surface level prequel (Water Overlay), if so configured). For locations without water areas, the water table is set to one meter below the surface.

The following Prequels are possible:

Default data

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).