Observing changes of the Hargen dunes using annual LiDAR data

Abstract

In 2003, the Hondsbossche and Pettemer Zeewering, located from Camperduin to Petten, was classified to not be within safety margins of the Dutch Coast. In order to protect the Dutch Coast from sea level rise, the Hondsbossche dunes were created in 2015. This project included the building of an artificial lagoon for recreational purposes. This lagoon is protected from the sea by three sand dunes. Without these dunes, the lagoon will not remain to exist. The aim of this study is to detect changes of the shape and the height of the dunes protecting the lagoon at Camperduin from the sea using annual lidar data.
JARKUS data is obtained from airborne laser scanning for the Dutch coastal areas which is done yearly between January and March. Eight datasets of annual lidar data which include the dunes are used for this study. The datasets consists of point clouds for the years 2016 to 2023.
To obtain information about the changes occurring, several methods are used. The workflow recommended is the C2M method for 3D changes. These changes can be clustered by K-means clustering. 2D changes can be observed using cross sections, contour lines and the volume changes.
The seaward side of the dunes decreases in height due to marine erosion such as storms. Around 4.5 meter erosion on some locations has been found due to large storms in 2022. The lagoon side of the dunes increases in height by aeolian transport. The rate of dune growth is found to be 0.5 meters per year.
The middle dune experiences more erosion than deposition and the volume decreases. The erosion is caused by less vegetation and human impacts. If the trend from before the storm in 2022 continues, the dune will shrink and disappear if no additional maintenance is done. The other two dunes do not experience big volume losses and are classified as stable.