Publication Date:
2021-03-29
Description:
The objective of this work is the simulation of
saturated and unsaturated flow in a karstified aquifer using
a double continuum approach. The HydroGeoSphere code
(
Therrien et al.
,
2006
) is employed to simulate spring dis-
charge with the Richards equations and van Genuchten pa-
rameters to represent flow in the (1) fractured matrix and
(2) conduit continuum coupled by a linear exchange term.
Rapid vertical small-scale flow processes in the unsaturated
conduit continuum are accounted for by applying recharge
boundary conditions at the bottom of the saturated model do-
main. An extensive sensitivity analysis is performed on sin-
gle parameters as well as parameter combinations. The tran-
sient hydraulic response of the karst spring is strongly con-
trolled by the matrix porosity as well as the van Genuchten
parameters of the unsaturated matrix, which determine the
head dependent inter-continuum water transfer when the con-
duits are draining the matrix. Sensitivities of parameter com-
binations partially reveal a non-linear dependence over the
parameter space. This can be observed for parameters not
belonging to the same continuum as well as combinations,
which involve the exchange parameter, showing that results
of the double continuum model may depict a certain de-
gree of ambiguity. The application of van Genuchten pa-
rameters for simulation of unsaturated flow in karst systems
is critically discussed.
Keywords:
saturated unsaturated flow; karst systems; catchment scale; double continuum
;
551
Language:
English
Type:
article
,
publishedVersion
Format:
15
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