Basic Concepts and Equations
This method can be used with Kinematic Wave, Modified Puls, Muskingum Cunge, and Normal Depth routing methods.
The inundated area is calculated for the current flow rate.
When used with the Normal Depth, Kinematic Wave, and Muskingum-Cunge methods, the wetted perimeter is multiplied by the reach length in order to compute the inundated area.
When used with the Modified Puls method, the optional Elevation-Discharge Function must be specified in the routing parameters. Flow depth is calculated for the current flow from the Elevation-Discharge function. The current storage is divided by the depth to get the inundated area..
The flow rate is multiplied by the time step and divided by the inundated area to get the depth of water on the inundated area for the time step.
Infiltration from the channel is calculated using the Green and Ampt Loss Model.
Loss rate is then calculated as the infiltration depth times the inundated area divided by the time step.
|
Q_{loss}=A \cdot{infiltration}/\Delta{t} |
Since no means for extracting infiltrated water is included, this method should only be used for single events.
Required Parameters
The initial moisture content or deficit defines the saturation of the soil layer at the start of the simulation. This parameter is a function of the channel moisture at the beginning of the simulation. It may be estimated in the same manner as the initial abstraction for other loss models.
The wetting front suction head describes the movement of water downwards through the soil column.
The saturated hydraulic conductivity defines the minimum rate at which precipitation will be infiltrated into the soil layer after the soil column is fully saturated.
Elevation-Discharge function for Modified Puls routing.
