A new coastal maintenance strategy designed to harness the power of winds, waves and currents to help protect part of the Dutch coast, while encouraging the development of new dunes, as well as the valuable flora and fauna associated with them.
The traditional approach to sand nourishment is primarily intended to maintain the shoreline using a volume of 2-5 million m³ of sand. Typically, nourishment operations have to be repeated every five years, resulting in the frequent disturbance of the ecosystem.
The Delfland Sand Motor experiment is a mega-nourishment operation that involved depositing 21.5 million m³ of sand in a single location, with the height of the deposit rising to 5 metres above the mean sea level. The wind and currents are gradually redistributing the sand along the shoreface, beach and dunes. By using natural processes to spread the sand, this innovative approach aims to limit the disturbance of local ecosystems, while also providing new areas for nature and more leisure opportunities.
The strategy of concentrating nourishment operations is seen as a climate-robust and environment-friendly way of countering coastal erosion. In addition, the temporary presence of surplus sand also creates new areas for nature and leisure. Nature is disturbed much less frequently than in the standard five-year cycle and there is more time for the development of new ecosystems with more biodiversity.
The Sand Motor pilot is a collaborative effort involving public authorities, private companies and research institutes. It has become a focal point for coastal research and innovative coastal management solutions. The project is being closely monitored and an extensive research programme has been established that will include detailed studies of the evolution of the Sand Motor and the driving forces behind it, whether physical, ecological or social.
Since the Sand Motor emerged from the waves in 2011, it has been closely monitored. Preliminary results show that it has behaved as predicted until now. Sediment is indeed being transported along the coast and into the dunes, seals have been visiting the area and a rare plant species has been found growing on a newly-formed juvenile dune. The Sand Motor has also become a highly popular location for wind-, wave- and kite-surfers.
The Building with Nature programme will draw on the results of the Delfland Sand Motor to develop:
– practical guidelines for the design and implementation of coastal maintenance projects;
– tools for the rapid assessment of optimal locations, as well as the volume, frequency and shape of nourishment operations;
– detailed simulation models to predict morphological evolution over time, the process of dune formation and the environmental impact;
– lessons learned, including the potential of concentrated nourishment operations to improve coastal protection, while also providing opportunities for nature and leisure;
– advice on the important issue of governance, such as how to identify (and involve) all relevant stakeholders and to ensure the participation of public, private and academic partners.