Dune toe dynamics along the urbanised macro‐tidal coast of Belgium

Abstract

The dynamics of the dune toe along the urbanised 65 km macro‐tidal coast of Belgium has been examined based on (bi‐)annual cross‐shore profiles derived from airborne LiDAR surveys conducted between 2000 and 2019. Results indicate that the average dune toe level is located at +5.9 m Tweede Algemene Waterpassing (TAW, Belgian Ordnance Datum), which is 1 m lower than the conventional dune toe level. However, this level is not static but rather increasing over time with an average rate of 2.3 cm/year, making it comparable with coastal areas along western Europe. Both landward retreat and seaward progradation of the dune toes are observed, with rates up to 2 m/year. The analysis revealed that dune growth is primarily facilitated by the development of incipient or embryonic dunes, new foredunes and modifications to the stoss slope of the original dune profile. Half of the sea‐fronting dunes were observed to be developed by brushwood fences, which had a positive effect on dune growth. At some locations, incipient dune development and shoreline progradation were observed seaward of old foredunes. Other dune regions were characterised by natural dune blowouts and management activities for recreational purposes. Dune toe reinforcements were implemented in the west to stabilise the dune toe and prevent erosion by waves. However, it was noted that if the adjacent beach accreted because of natural growth or periodic nourishment, incipient dunes could form in front of the reinforcement.

Drivers of plant-associated invertebrate community structure in West-European coastal dunes

“…Marram grass spatial contagion, cover and vitality are directly linked to the prevailing sand dynamics (Huiskens 1979, Nolet et al 2018, Reijers et al 2021, Bonte et al 2021, Strypsteen et al in press) and these days directly managed through planting actions to stabilise existing dunes and/or promote the evolution of new dunes in front of urban areas as a Nature-based solution for coastal protection (van der Meulen et al 2023). These actions consequently have an immediate impact on the system’s biodiversity value.…”