Construction of sills
Elevating sills in the riverbed (making it shallower) increases the water level during dry periods. The meanders that we will reconnect to the Demer have a higher bed-level than the Demer. By placing small sills in the river at the site of the meanders, the water can flow back through these meanders. This will not only raise the level of the Demer, it will also raise the level of the groundwater. This rewetting process will, in turn, give the wetlands nature in the valley a serious boost.
The sills do not increase the risk of flooding, because when the water levels rise, the river water will simply flow over them.
Under normal conditions, the water will therefore flow through the meanders. And this brings many benefits. When the water level is high, the water flows through the meanders as well as over the sills. The discharge capacity is not reduced. This design combines the best of both worlds.
The sills are an intervention with a beneficial effect on the wetland forests and grasslands along the river. After all, rewetting facilitates biodiversity. Depending on the substrate, highly varied wetlands will develop, ranging from open reed marshes to hay meadows full of flowers.