The Kwetshage area is situated in the coastal province of Flanders, nearby the city of Bruges. It has an area of approximately 90 ha, and it is former agricultural land, situated in a polder region. It is part of a Natura 2000 habitat restauration area, with a target of realizing 50 ha of wetland/reed marsh.
The project area is on one hand a transit area for upstream water evacuation but also a flood zone. So the challenge was to create a wetland in a floodzone by on the one hand creating higher water levels in the area and on the other hand maintaining or even increasing the buffer capacity as a flooding area. Rising the water level means the loss off buffercapacity: the hydrological model for the area predicts a loss off 140.000 m3 of buffercapacity when the water levels were rised in the project area to meet the needs of realizing 50 ha of wetland.
The solution was a combination of:
- Rising water levels, in a differentiated way over the project area
- Shallow excavations, to lower the ground level
- Minimizing drainage of the area, by relocation of the main watercourse that crossed the area.
The lessons learned were:
- For these types of projects modeling is essential to evaluate different scenario’s
- With differentiaton in project goals and use of techncal means you can realize rewetting without loss of bufercapacity
- These sort of projects are not possible to realize without hard instruments, such as expropriation or realotment.
BUFFER+ partner Flemish Land Agency worked on all aspects towards realisation, this included research, technical design, modelling, and the final implementation.
