Terrain water manning (Water Overlay)

The default value for the WATER_MANNING attribute of surface type "Open land". The user can change this value.

Icon	Attribute	Unit	Layer	Range	Description
	WATER_MANNING	s/(m^1/3)	Surface		The Gauckler–Manning coefficient of the terrain, which is a measure of surface roughness. Used in the surface flow computation of the Water Overlay.

Terrains have an inherent "roughness", affecting the flow of water across their surface, which is expressed by the Gauckler–Manning coefficient or, in short, Manning's value (n).

Notes

The values for this attribute are clamped between 0.01 and 0.255.
The manning value can alternatively be provided as a prequel.
The default values for this attribute are derived from online accessible databases^[1] and are readily adjusted by the user.
If a building is present on the terrain, the WATER_MANNING value of the building is used instead.
Only terrains of type 'surface' have an assigned WATER_MANNING.