Morphodynamics of sandy anthropogenic shores | Beach-dune systems affected by human action
Manuel Teixeira Manion is a PhD student in the department Coastal Systems and Nature-Based Engineering. (Co)Promotors are prof.dr. K.M. Wijnberg and dr.ir. E.M. Horstman from the faculty Engineering Technology from the University of Twente.
This thesis investigates how human activities and natural dynamics jointly shape the long-term development of Sandy Anthropogenic Shores (SAS)—coastal landscapes created by large-scale sand nourishments, such as the Sand Motor and Hondsbossche Dunes in The Netherlands. These engineered interventions aim to improve flood safety, promote dune formation, and enable ecological and recreational use.
However, how natural dynamics and human activities interact to influence the morphological development of SAS remains insufficiently understood. To address this, the thesis extends and applies the DuBeVeg model, a cellular automata framework for simulating decadal beach-dune evolution. DuBeVeg was enhanced to better represent aeolian sand transport, sediment availability, and surface armouring, which are processes especially relevant for SAS.
These improvements made it possible to simulate the formation and spatial variability of embryonic dunes, and to explore how these patterns develop over time in a transient SAS such as the Sand Motor. The simulations also showed how initial design choices influence long-term dune development. For example, the armour layer that develops when the nourishment material is less wellsorted and coarser than native beach sand, led to the emergence of more scattered and isolated dunes compared to a nourishment with native beach sand. A key contribution of this thesis is the integration of recreational impacts into the model. By including the effects of car and foot traffic on vegetation, it was possible to explore how human use affects dune morphology and sand distribution.
The results suggest trade-offs between recreation and ecological diversity, and point to management strategies such as zoning or limiting access. The extended DuBeVeg model serves as a tool for assessing design and management scenarios. It offers insights into how SAS can be planned to balance flood protection, ecological value, and recreation, supporting the development of resilient coastal landscapes through nature-based solutions
