Hydrological attributes of terrains (Water Overlay)

Terrains have several hydrological properties that influence water flow within a project. Since surface and underground terrain cover the entire project area, all cells use these properties unless overridden by a building.

Icon	Attribute	Unit	Layer	Range	Description
	HYDRAULIC_CONDUCTIVITY_MD	m/day	Ground		Hydraulic conductivity (K) is a measure of the ease with which water can move through pore spaces or fractures in a saturated medium.
	HYDRAULIC_CONDUCTIVITY_WITH_THICKNESS_MD	m2/day	Ground		This attribute represents the horizontal hydraulic conductivity (KD) of the saturated layer multiplied by the layer thickness.
	GROUND_INFILTRATION_MD	m/day	Surface	0.0 to 10.0	The speed at which water can flow vertically from the surface to the unsaturated zone.
	GROUND_INFILTRATION_MD	m/day	Ground	0.0 to 10.0	The speed at which water can flow vertically from the unsaturated zone to the saturated zone.
	ROOT_DEPTH_M	m	Surface		The depth of the roots of the Terrain Type. This depth is used to determine whether evaporation will occur from the groundwater.
	VAN_GENUCHTEN_M	fraction	Ground	0.05 to 1.0	Van Genuchten Soil Parameter M needed to calculate the Soil Water Retention Curve in the Unsaturated Zone.
	WATER	nominal	Surface		Whether this Terrain Type represents a form of water (and what type).
	WATER_TRANSPIRATION_FACTOR	factor	Surface		How fast this terrain can evaporate water from the ground. The weather's evaporation speed is multiplied by this factor to determine the rate of transpiration.
	WATER_MANNING	s/(m1/3)	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.
	WATER_MICRORELIEF_M	m	Surface	0 - 0.255	The defined Microrelief in meters, which captures surface water. When captured, surface flow is halted until the defined threshold is reached. Evaporation and infiltration for water captured in Microrelief is still allowed.
	WATER_STORAGE_PERCENTAGE	fraction (m3/m3)	Ground		The percentage (as a fraction) of the ground layer volume which can be filled with water. A lower percentage means the ground layer will be able to store less water, and the saturated zone will rise higher with the same amount of water in the ground layer.

Notes

• In general, surface Terrain Attributes can be overridden by attributes of buildings on the surface, even when the attribute values of the building are set to 0.

API Endpoints

• Api session event editor terraintype set attribute

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Terrain attributes

Terrain attributes

Ground infiltration md •  Hydraulic conductivity md •  Hydraulic conductivity with thickness md •  Root depth m •  Water •  Water transpiration factor •  Water manning •  Water microrlief m •  Water storage percentage •  Van genuchten m

Related

Building attributes • Hydrological features • Hydraulic structures • Model attributes • Prequels • Results • Simulation data