Groundwater Prequel (Water Overlay)

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

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

Values in the groundwater GeoTIFF 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 GeoTiff is not configured for the Water Overlay, the watertable is initialized using the WATER_LEVEL attribute of the water level area instead. For locations without water level areas, the water table is set to one meter below the surface.

Groundwater depth GeoTIFF specification
Description	The depth of the ground water level, relative to the surface.
Value	Groundwater level (m below terrain height)

Groundwater datum GeoTIFF specification
Description	The datum height of the ground water level.
Value	Groundwater level (m + datum)

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).

How-to's

• How to use a default groundwater GeoTiff (Water Overlay)
• How to upload and use a groundwater GeoTiff (Water Overlay)

See also

• Water level area (Water Overlay)
• Underground model (Water Overlay)
• Ground watertable result type (Water Overlay)

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Water Module

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Bottom distance • Bottom pressure • Bottom resistance • Ground conductivity • Groundwater datum • Groundwater depth • Manning • Max infiltration • Microrelief • Surface level • Surface u • Surface v • Terrain elevation • Unsaturated fraction

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