Drainage (Function Value)

Function value	Attribute	Unit	Per category	Range	Description
Drainage	DRAINAGE	m			Whether this construction has drainage, which affects the calculation of the Subsidence Overlay.

Values

• The default values for this Function Value are configured for specific constructions which represent drainage. The specific values are determined in cooperation with the export party who commissioned the Subsidence Overlay.
• The default values are not overwritten during the creation of a new project.

Used for

• Subsidence (Overlay)

Notes

• A negative value means passive drainage, fixing the groundwater level to the surface water level. A positive value means active drainage, keeping the ground water level at a specific height.
• Although the effect of drainage to subsidence are via an intermediate effect on groundwater, this value is not used for the Water Overlay. To model drainage in the Water Overlay, use an Aquifer instead.