Assessment of saturated hydraulic conductivity-depth relationships and
extended soil column thickness in catchment hydrological modelling
Abstract
“‘latex
An appropriate soil configuration is essential in hydrological models
given the role of subsurface processes in the hydrological functioning
of a catchment. Hydrological models are typically set up with shallow
soil depths as restricted by measurements and soil datasets that are
often unavailable in greater depths. While this may be sufficient for
some catchments, in some areas the water table is located deeper and
thus the shallow groundwater and its link with the rest of the
hydrological processes may not be captured well by the model. An
important soil parameter, that is known to vary with soil depth, is the
saturated hydraulic conductivity (K sat). In this study,
we assessed different vertical profiles of K sat which
exceed the typical soil measurement depths. The K sat
profiles were implemented in wflow.jl for the distributed hydrological
model wflow_sbm and tested for the Vecht catchment. Results
demonstrated that increasing the soil thickness and implementing any of
the K sat profiles assessed improved the discharge and
mean groundwater depth predictive capabilities, albeit altering the
groundwater dynamics. A sensitivity analysis revealed the respective
influence of four model parameters on the groundwater dynamics which can
be used as basis to optimize the model performance further.