Hydrological attributes of terrains (Water Overlay)
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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 |
|---|---|---|---|---|---|
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HYDRAULIC_CONDUCTIVITY_MD | m/day | Ground | The hydraulic conductivity (symbolically represented as K) is defined as the speed by which water moves through the saturated zone horizontally. | |
| |
HYDRAULIC_CONDUCTIVITY_WITH_THICKNESS_MD | m2/day | Ground | The hydraulic conductivity (symbolically represented as KD) is defined as the speed by which water moves through the saturated layer horizontally, multiplied with the layer thickness. | |
 |
GROUND_INFILTRATION_MD | m/day | Surface | 0 to 10 | The speed at which water can flow vertically from the surface to the unsaturated zone. |
| |
GROUND_INFILTRATION_MD | m/day | Ground | 0 to 10 | The speed at which water can flow vertically from the surface to the unsaturated 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). | ||
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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. | |
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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. | |
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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.
- Group
- Terrain attributes