GreenAmptInfiltration Class Reference

Connects the surfacewater and the most upper layer using a Green-Ampt equation like infiltration. More...

Inheritance diagram for GreenAmptInfiltration:

Collaboration diagram for GreenAmptInfiltration:

Detailed Description

Connects the surfacewater and the most upper layer using a Green-Ampt equation like infiltration.

The Green-Ampt formula is given as:

\[q(t) = -K_s \frac{dh}{dz} A\]

where:

• \(q(t)\) is the infiltration rate in m3/day
• \(K_s\) is the saturated conductivity in m/day
• \(\frac{dh}{dz}\) is the hydraulic gradient in the wetting front
• \(A\) is the surface area of the cell

The gradient in the wetting front is calculated as:

\[\frac{dh}{dz} = \frac{h_f - h_0}{Z_f} = \frac{|\Psi_f| + Z_f}{Z_f}\]

where:

• \(h_f\) is the hydraulic head at the bottom of the wetting front in m
• \(h_0\) is the hydraulic head at the surface in m
• \(Z_f\) is the length of the wetting front in m

Since \(Z_f\) is unknown, the depth of the wetting front can be approximated by:

\[Z_f = \frac{F}{\theta_s - \theta_i}\]

with:

• \(F\) the accumulated volume per area of infiltrated water
• \(\theta_s, \theta_i\) the volumetric water content at saturation resp. at start of the infiltration

If the surface water is modeled by a distinct water storage, the actual infiltration is given as the product of the potential infiltration with the coverage of the surface water cmf::upslope::Cell::surface_water_coverage

\[q_{act} = q_{max} \frac{A_{water}}{A_{cell}}\]

If the surface water is no storage on its own, but just a water distribution node, the actual infiltration is the minimum of the potential infiltration and the current inflow (rain, snow melt) to the surface

\[q_{act} = \min\left(q_{max}, \sum{q_{in,surfacewater}}\right)\]

Public Member Functions
real	conc (cmf::math::Time t, const cmf::water::solute &_Solute)
	Returns the concentration of the flux.
flux_node::ptr	get_target (const flux_node &inquirer)
	Returns the other end of a connection than the asking end.
flux_node::ptr	get_target (int index) const
	With index 0, the left node is returned, with index 1 the right node of the connection.
real	get_tracer_filter ()
	A value ranging from 0 to 1 to filter tracers out of the water flux.
real	get_tracer_filter (solute S)
	A value ranging from 0 to 1 to filter tracers out of the water flux.
bool	kill_me ()
	Deregisters this connection from its nodes. Returns true if only one reference is left.
flux_node::ptr	left_node () const
	Returns the left node of this connection.
real	q (const flux_node &inquirer, cmf::math::Time t)
	Returns the current flux through a connection. Negative signs mean out of the inquirer, positive are inflows to the inquirer.
void	refresh (cmf::math::Time t)
	Performes a new calculation of the flux.
flux_node::ptr	right_node () const
	returns the right node of this connection
void	set_tracer_filter (real value)
	A value ranging from 0 to 1 to filter tracers out of the water flux.

Static Public Member Functions
static void	use_for_cell (cmf::upslope::Cell &c)
	Creates the connection between surfacewater and first soil layer.

Public Attributes
const std::string	type
	A string describing the type of the connection.

Member Function Documentation

conc()

real conc ( cmf::math::Time t, const cmf::water::solute & _Solute )

inherited

Returns the concentration of the flux.

If not overridden, it returns the concentration of the source of the flux (direction depending)

get_tracer_filter()

real get_tracer_filter ( )

inherited

A value ranging from 0 to 1 to filter tracers out of the water flux.

1.0 is no filter and 0.0 means no solute is crossing this connection

set_tracer_filter()

void set_tracer_filter ( real value )

inherited

A value ranging from 0 to 1 to filter tracers out of the water flux.

1.0 is no filter and 0.0 means no solute is crossing this connection