The equation that governs water flow in aquifers. It is derived with continuity from Richards equation.

1. L’equazione delle Falde
Riccardo Rigon
JayStrattonNoller,DepoeConvexus

2. R. Rigon
2
What I mean with Richards ++
Extending Richards to treat the transition saturated to unsaturated zone.
Which means:
At the transition with saturation
R. Rigon and E. Cordano

3. R. Rigon
3
So we switch to a generalised
groundwater equations
which has been obtained by modifying the SWRC
At the transition with saturation
R. Rigon and E. Cordano

4. !4
Richards equation is part of a more general equation
that can be obtained by considering also saturated soil/aquifers*
* see for instance, Lu and Godt, 2012, Chapter 4 - Freeze and Cherry, 1979, pg 51
Since the rate of gain/loss of water mass is in general:
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where:
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R. Rigon
Extensions

5. !5
Allora l’equazione generale è ancora
C(⇥)
⇤⇥
⇤t
= ⇥ · K( w) ⇥ (z + ⇥)
⇥
purchè (usando la parametrizzazione di van Genuchten):
R. Rigon
Extensions