Surface infiltration formula (Water Overlay): Difference between revisions

Latest revision as of 14:40, 5 March 2024

Surface infiltration is the amount of water that infiltrates from the surface to the unsaturated zone below the surface.

Surface infiltration is calculated per grid cell. First, the infiltration capacities are calculated:

{\bar {I}}_{top}={\begin{cases}{\bar {I}}_{building},&{\text{if building are present on top of the surface}}\\{\bar {I}}_{terrain},&{\text{otherwise}}\\\end{cases}}

{\bar {I}}_{surface}=min({\bar {I}}_{ground},{\bar {I}}_{top})

Then the actual infiltration:

\Delta w_{t}=min(h_{t},{\bar {I}}_{surface}\cdot \Delta t\cdot f_{i,t})

Where:

{\bar {I}}_{building}

= The average infiltration capacity based on buildings on top of the surface, based on GROUND_INFILTRATION_MD defined in either the building or function.

{\bar {I}}_{terrain}

= The average infiltration capacity based on the surface terrain, defined by GROUND_INFILTRATION_MD. This value should be interpreted as the vertical conductivity (Kv) of the sub-soil.

{\bar {I}}_{top}

= The average infiltration capacity on top of the surface.

{\bar {I}}_{ground}

= The average infiltration capacity below the surface.

{\bar {I}}_{surface}

= The infiltration capacity from surface to the unsaturated zone.

\Delta w_{t}

= The surface infiltration which takes place at time

t

.

h_{t}

= The amount of water on the surface at time

t

. Also known as the water column.

\Delta t

= Computational timestep.

f_{i,t}

= The interpolated infiltration factor at time

t

. Configured using INFILTRATION_FACTOR_S.

Notes

When Surface infiltration Only is active, the maximum amount of water that can infiltrate into the unsaturated zone can be configured. See Infiltration Model: Surface infiltration Only for more details.

How-to's

How to configure a dynamic infiltration factor for a Water Overlay

Models

Surface • Ground • Rain • Evaporation • Infiltration • Elevation • Breach • Sewer • Storage • Tracer flow • Border • Order
Model formulas

Timestep • Season • Surface water level • Groundwater level
Flow formulas

Surface flow • Surface infiltration • Ground flow • Ground infiltration • Surface evaporation • Ground evaporation • Ground bottom flow
Hydraulic structure formulas

Culvert • Weir • Breach growth • Breach flow • Pump • Sewer Overflow • Inlet • Drainage
Related

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

@@ Line 1: / Line 1: @@
-Surface infiltration is calculated per cell.
+Surface infiltration is the amount of water that infiltrates from the surface to the unsaturated zone below the surface.
-First, the infiltration capacities are calculated:
+Surface infiltration is calculated per grid cell. First, the infiltration capacities are calculated:
-: ''C<sub>water</sub> = W<sub>surface</sub>''
-: ''C<sub>top</sub>'' = max( I<sub>con</sub>, I<sub>surf</sub> )
+:<math> \bar{I}_{top} =
-:: I<sub>surf</sub> = 0 if a construction is present
+\begin{cases}
-:: I<sub>con</sub> = 0 if no construction is present
+\bar{I}_{building}, & \text{if building are present on top of the surface} \\
+\bar{I}_{terrain}, & \text{otherwise}\\
+\end{cases}
+</math>
+:<math> \bar{I}_{surface} = min(\bar{I}_{ground}, \bar{I}_{top})</math>
 Then the actual infiltration:
-: ''Δw =  min( C<sub>water</sub> , Δt * C<sub>top</sub>)''
+:<math>\Delta w_t = min( h_t, \bar{I}_{surface} \cdot \Delta t \cdot f_{i,t})</math>
 Where:
-* Δw = The surface infiltration which takes place.
-* <math>\deltat</math> = Computational timestep.
-* C<sub>water</sub> = The amount of infiltration that can take place based on the amount of water on the surface.
+: <math>\bar{I}_{building}</math> = The average infiltration capacity based on [[building]]s on top of the surface, based on [[Terrain ground infiltration md (Water Overlay)|GROUND_INFILTRATION_MD]] defined in either the [[Building|building]] or [[Function|function]].
-* C<sub>top</sub> = The amount of infiltration that can take place based on the infiltration values present.
+: <math>\bar{I}_{terrain}</math> = The average infiltration capacity based on the surface [[terrain]], defined by [[Terrain ground infiltration md (Water Overlay)|GROUND_INFILTRATION_MD]]. This value should be interpreted as the vertical conductivity (Kv) of the sub-soil.
+: <math>\bar{I}_{top}</math> = The average infiltration capacity on top of the surface.
+: <math>\bar{I}_{ground}</math> = The average infiltration capacity below the surface.
+: <math>\bar{I}_{surface}</math> = The infiltration capacity from surface to the unsaturated zone.
-* W<sub>surface</sub> = The amount of water (the water column) on the surface.
+: <math>\Delta w_t</math> = The surface infiltration which takes place at time <math>t</math>.
-* I<sub>con</sub> = The [[Terrain ground infiltration md (Water Overlay)|GROUND_INFILTRATION_MD]] of a construction on a specific cell (if present).
+: <math>h_t</math> = The amount of water on the surface at time <math>t</math>. Also known as the water column.
-* I<sub>surf</sub> = The [[Terrain ground infiltration md (Water Overlay)|GROUND_INFILTRATION_MD]] of the surface terrain type. This value should be interpreted as the vertical conductivity (Kv) of the sub-soil.
+: <math>\Delta t</math> = Computational [[Timestep formula (Water Overlay)|timestep]].
+: <math>f_{i,t}</math> = The interpolated infiltration factor at time <math>t</math>. Configured using [[Infiltration_factor_s_(Water_Overlay)|INFILTRATION_FACTOR_S]].
 ==Related==
 The following topics are related to this formula.
 ; Formulas
-: [[Surface water level formula (Water Overlay)|Surface water level formula]]
+: [[Surface water level formula (Water Overlay)]]
-: [[Groundwater level formula (Water Overlay)|Groundwater level formula]]
+: [[Groundwater level formula (Water Overlay)]]
-: [[Underground infiltration formula (Water Overlay)|Underground infiltration formula]]
+: [[Ground infiltration formula (Water Overlay)]]
 ; Models
-: [[Surface model (Water Overlay)|Surface model]]
+: [[Surface model (Water Overlay)]]
-: [[Underground model (Water Overlay)|Underground model]]
+: [[Ground model (Water Overlay)]]
-: [[Infiltration model (Water Overlay)|Infiltration model]]
+: [[Infiltration model (Water Overlay)]]
-: [[Substance flow model (Water Overlay)|Substance flow model]]
+: [[Tracer flow model (Water Overlay)|Tracer flow model]]
-{{Template:WaterOverlay_nav}}
+{{Article end
+|notes=
+* When Surface infiltration Only is active, the maximum amount of water that can [[Max infiltration m (Water Overlay)|infiltrate into the unsaturated zone]] can be configured. See [[Infiltration_model_(Water_Overlay)#Surface infiltration Only|Infiltration Model: Surface infiltration Only]] for more details.
+|howtos=
+* [[How to configure a dynamic infiltration factor for a Water Overlay]]
+}}
+{{WaterOverlay formula nav}}

Surface infiltration formula (Water Overlay): Difference between revisions

Latest revision as of 14:40, 5 March 2024

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