An old technique, called wiepen, is applied in strengthening the dike on Marken. Bundles of branches have been seen along the dike in recent weeks. But what exactly are wiepen, and why are they used?
Wiepen are bundles of willow branches. The dike workers place them on top of a plastic sheet (geotextile) to ensure it stays in place.
The geotextile is a fabric made of synthetic fibers that lets water through but not sand. This way, the sand cannot disappear due to currents and waves.
Geotextile works like root cloth in your garden, explains Thomas Wassenaar, implementation manager at Combinatie Hof on Marken. Water goes through, but the soil stays put. Without this protection, the sand we are now applying could wash away, for example during a storm.