The Rivierenland Water Board subsequently contracted us to insert geotextile along the inner berm of the dikes near both Ingen and Rijswijk, as an alternative to regular dike upgrade methods. We have processed approximately 700 metres of geotextile along both stretches, taking two business days for each stretch. Including preparatory and completion stages, this meant that people living near the dike only had to deal with machines and work for the better part of a week. Nevertheless, the dikes are now as effectively protected against piping as they would be after a lengthy reinforcement by conventional means.

Monitoring geotextile permeability

To avoid piping, it is important that water can flow freely through the geotextile. To measure this permeability, we included monitoring cables on both sides of the geotextile installed near Rijswijk and Ingen. These cables measure the difference in water currents in front of and behind the textile barrier. If there is no difference between the two readings, this means the geotextile is effectively permeable. In addition, the system uses monitoring wells to keep track of the local pore pressure.