Deltalife 13

Deltares, spring 2020 26 A section of eleven kilometres of dike between Kinderdijk and Schoonhovenseveer (KIS) was not strong enough. That was the con- clusion in 2007 of the safety analysis conducted by the water authorities every twelve years. There was a risk of the dike failing if the water level rose substantially. Time to strengthen the dike on the south bank of the Lek river. Under themanagement of the Rivierenland water authority, that operation was completed between 2013 and 2018. A combination of factorsmeant this was a challenging project. First of all, in technical terms: the soft peat soil made it complicated to strengthen the dike. And there are a lot of buildings in the area. Finally, the dike serves as a connecting road and there are a lot of cables and pipelines beneath the surface. Project manager Bramde Fockert of the Rivierenland water authority and his colleague HansMerks, theWater and Dike Policy teammanager, were closely involved. They look back on six lessons learnt. Dike of the future As the water in the Netherlands rises, the land is subsiding. Higher and stronger dikes are needed, especially since the introduction of stricter safety standards in 2017. The dike between Kinderdijk and Schoonhovenseveer has already been strengthened. What six lessons can we learn from this complex project? By Thessa Lageman /Photo Peter de Krom Lesson 1: Get local residents involved early In all, there were 450 houses on the dike which passes around and through the villages of Nieuw- Lekkerland, Streefkerk and Groot-Ammers. Starting in 2007, employees of the Rivierenland water authority got round the table with the residents to discuss the plans for the upgrading of the dike. 'We were able to save people's homes in some locations,' recalls De Fockert. 'But a berm has now been put into place in others. That has all been done in close consultation. A number of residents wanted to leave; others wanted to have their homes built back up. In the end, 58 houses were demolished and 25 were rebuilt. The government paid the market value for the houses.' Getting the residents