This study aims to restore two depressional wetlands in the Breeven site by manipulating the local drainage network. Temporary weirs made of sandbags will be installed in two ditches to block drainage and increase water retention. Groundwater levels and discharge will be closely monitored using piezometers and a Venturi channel. The targets are to protect wet nature and restore the local hydrological system by increasing water retention and storage. Based on the results, permanent measures may be installed ranging from adjustable weirs to completely filling the ditches. Field data will also be compared to modeling scenarios to improve existing hydrological models.

1. Restoring the Breeven, ditch by ditch
Master project by Jarne Colman; University of Antwerp, Ecosphere research group
Supervised by Dr. Jan Staes and Jayson Pinza; part of the Turquoise research project
Study site: Breeven
Research methodology
• 2 ditches, 4 depressional wetlands
• For each wetland → 1 ditch in which drainage converges
• Easy to monitor and block off
• Why depressional wetlands? → important for water-retention
• Local seepage very sensitive to drainage
• Hotspots for endangered wetland nature (e.g., fens & wet heath)
• Manipulating the drainage network
• Installment of temporary weirs made from sandbags
• Cheap + easy to install & modify
• Monitoring
• (Ground)water levels → dense network of piezometers
• Benefits of using denser networks? Capturing micro-variations?
• Discharge → Venturi-channel
Targets
1) Protecting/restoring wet nature
2) Restoring local hydrological system
• Increasing water-retention & storage
After this study?
• Permanent measures to stop drainage
• Extent depending on results: from adjustable weirs up to
filling up of entire ditches
• Comparing field-data with modelling scenario’s
• Chance to improve existing models, reducing the need for
expensive field-research
• Improved models could then be used for the rest of the area, or
for other sites
• Moving on to other sites?
• Often difficult due to patchwork of stakeholders and
landowners, each with different aims and dealbreakers
• Mostly owned by Natuurpunt
→ bought with blue deal funding
→ 1 partner = simple communication
• 1 site <=> 1 hydrological system
• Old pine plantation
→ raised groundwater doesn’t affect farmers
External partner:
Research questions
• Focus: effect of blocking drainage channels
on water-retention and groundwater-levels?
• Bonus: effect of weir management (irregular
openings) on effectiveness of weirs as a
water-retaining measure?
SuSanA Secretariat,CC BY 2.0