View source for Drainage (Subsidence Overlay)

{{Overlay keys|<onlyinclude>
{{Overlay keys|type=row|group=Subsidence Overlay
|key=DRAINAGE
|unit={{mdatum}}
|description=The Drainage value has several behaviors, depending on its value. See the behavior description below.

|defaultvalue=n/a
|icon=subsidencewizard_icon_water_level.png
}}</onlyinclude>}}

===Drainage behavior===
* A drainage is active when the Drainage value is larger than 0. In this case, the drainage always sets the ground water level to the same relative depth. The drainage value indicates the relative depth of the ground water.
* A drainage is passive when the Drainage value is smaller than 0. In this case, depending on which ground water level is used (high or low), the water level is additionally adjusted with the [[Hi passive drainage (Subsidence Overlay)|high]] or [[Low passive drainage (Subsidence Overlay)|low passive drainage]] value configured for the [[Subsidence Overlay]]. In this case, the actual negative value of the drainage does not matter.
* In case the drainage value is zero, the [[Drainage feature (Subsidence Overlay)|Drainage]] has no influence on the groundwater level. In this case the [[Ground_water_depth_formula_(Subsidence_Overlay)|general method]] to calculate the distance between the Surface and the Groundwater Level is used.

{{article end
|seealso=
* [[Water level area (Subsidence Overlay)|Water level area]]
}}

{{SubsidenceOverlay feature attribute nav}}