Climate change is causing more extreme weather patterns with increased droughts and floods. Historically, landscapes have been drained quickly which lowers groundwater levels, impacting households, industry, agriculture and nature. Upstream depressional wetlands can buffer water and slowly infiltrate it to increase groundwater levels and baseflow during drought by closing drainage ditches. Three wetlands in Belgium are being monitored to analyze the effects of ditch closure on groundwater levels and inform hydrological modeling and scenario analysis to assess groundwater impacts at larger scales.

1. Upstream depressional wetlands can buffer and
infiltrate water to bridge drought periods
Problem
Because of climate change our weather pattern is becoming less unstable so that we are more likely to experience
more droughts and floods in the future. Over many centuries, our landscapes have been designed to drain water
as quickly as possible, e.g., ditches or soil sealing, to streams, rivers and to the sea. As a result, groundwater
levels are declining, which is problematic for households, industry, agriculture and nature.
Upstream Depressional
Wetlands
Groundwater level increase
Imagine an upstream depressional wetland as a bathtub filled with
groundwater, with the tap as rain, and a pipe at the side representing
a drainage ditch so that the bathtub can never fill up completely. If we
would close the ditch, for example with a weir, and so holding up the
water inside the depression, we could possibly obtain a groundwater
level increase of 50 cm! (Site of Kasterlee, period March 2021- February 2022)
Monitoring of water regulation functions
Three upstream depressional wetlands in the sandy soils of
the Campine region in Belgium are being monitored.
Groundwater level(1), precipitation and other weather
parameters(2) and drainage outflow(3) are continuously
being measured.
What is the effect of closing the drainage ditch on
the groundwater level?
Restoration of Upstream Depressional
Wetlands
Because of high fluctuations in groundwater level, these
depressions can buffer and slowly infiltrate water which
recharges groundwater and increases baseflow during
subsequent periods of drought. However, these depressions
are being drained through ditches for agriculture.
KASTERLEE
Next steps
Hydrological modelling and
upscaling to assess the impact of
closing the drainage ditch on
groundwater levels.
Scenario analysis, where different
weather and drainage scenarios can be
combined with inputs from farmers,
nature organisations and governmental
organisations.
Contact
Annelies Broeckx
Universiteit Antwerpen –
onderzoeksgroep ECOSPHERE
annelies.broeckx@uantwerpen.be
Jan Staes and Patrick Meire (UAntwerpen), Sarah Garré (ILVO),
Jan Vanderborght (KU Leuven)
This project is being part of the research project TURQUOISE.
Groundwater level decrease
because of drainage loss
and other causes
Topography
Desired
groundwater level
Groundwater flow directions
1
2
3