Beschrijving
viiiAbstract
Weir-controlled ditches are increasingly used in agricultural landscapes to enhance groundwater
recharge and mitigate water scarcity. This study refines the representation of ditch–weir
dynamics in soil water–groundwater models and quantifies the effects of weir operation on
water fluxes. Using the Gondebeek catchment in Melle, Belgium, as a case study, a two-
dimensional HYDRUS model is developed to simulate ditch–groundwater exchanges under
varying operational conditions. Two model setup versions are made: a “carved” version where
the ditch is represented using a vertical ditch wall and a horizontal floor whose length is half its
width in the field, and a “folded” version where this ditch floor is “rotated” to the vertical, thus
extending the vertical ditch wall length. Constant head and seepage face boundary conditions
are used to represent the ditch behavior. The model is then applied to compare open and closed
weir scenarios. Calibration against observed piezometer data demonstrated that aligning
observation nodes with ditch water levels (rather than from the model domain’s horizontal
bottom) improved model performance.
Results showed that closing the weir, with ditch water maintained at 70 cm depth, increased
groundwater levels near the ditch and enhanced infiltration, evaporation, and soil water storage,
while reducing drainage outflow.
This work demonstrates that realistic representation of ditch–weir interactions require careful
integration of geometry, boundary conditions, and soil parameters. Proper assessment of weir’s
hydrological impacts requires proper positioning of relevant observation nodes. The findings
provide practical insights into the hydrological trade-offs of weir management and offer a
framework for optimizing groundwater enhancement strategies involving agricultural drainage
systems
| Periode | 27-sep.-2025 |
|---|---|
| Mate van erkenning | Nationaal |