5.5 Soils
Last updated
Last updated
5.5.1 Rootzone physical maps
An overview of the Soils tab is shown in Figure 34. The rootzone physical maps refer to the physical soil properties of the first soil layer, where the subzone physical maps refer to the second soil layer’s physical properties. The settings in this tab significantly affect soil water processes in the root- and subzone, such as e.g., lateral flow, surface runoff, percolation, and evapotranspiration. Details regarding these processes can be found in the Theoretical section of this manual (Section 2). The user needs to select the following five rootzone physical maps:
Field capacity [mm/mm]
Saturated content [mm/mm]
Permanent wilting point [mm/mm]
Wilting point [mm/mm]
Saturated hydraulic conductivity [mm/d]
These maps can be selected and added to the map canvas by clicking the Select map buttons. It is important to check that the cell values should increase from permanent wilting point to wilting point to field capacity, and with saturated content having the highest cell values. Figure 35 shows an example of a field capacity map for the rootzone, showing more details in the upstream part than the downstream part.
5.5.2 Subzone physical maps
For the subzone physical maps the user has to select the following three maps:
Field capacity [mm/mm]
Saturated content [mm/mm]
Saturated hydraulic conductivity [mm/d]
These maps can be selected and added to the map canvas by clicking the Select map buttons. For the subzone physical maps it is important to check that the cell values of the saturated content map are higher than for the field capacity map.
5.5.2 Root- and subzone parameters
The last section of the Soils tab involves setting the soil layer thickness for both the root- (left part) and subzone (right part). The user can opt to provide a homogeneous rootzone and/or subzone soil depth for the entire basin, or to provide a spatial map with a spatially distributed soil depth over the entire basin. In Figure 34 we chose to select a spatially distributed soil depth map for both the root- and subzone. These maps can be selected and added to the canvas by clicking the Select map button.
If you prefer to have a homogeneous soil depth for the entire basin, then a default value of 500 mm for the rootzone, and 1500 mm for the subzone are good values to start with.
The final setting in the Soils tab involves setting a value for the maximum capillary rise. This value affects the maximum amount of water that can travel from the subzone to the rootzone on a daily basis due to evapotranspiration demand.
After completing all settings in the Soils tab the user can continue with the next tab: Groundwate
