Lunchtalk by Dr. ir. Erik Horstman


Mangrove Resilience for Enhanced Safety of Coastal Urbanisations and Environments

Mangrove ecosystems significantly reduce flood risks in low-elevation coastal areas, well-known hotspots for population and economic growth. Mangroves’ capacity to attenuate hydrodynamic forces and to accumulate sediments provides them with a natural resilience to buffer the impacts of flood events and to adapt to changes in environmental conditions. Nevertheless, mangroves are increasingly stressed by reduced sediment supply, accelerated sea-level rise and other anthropogenic impacts. Critical thresholds to mangrove resilience may be reached and quantitative insights into how such factors affect biophysical interactions in mangroves are required to develop predictive models to help assess mangrove shorelines’ vulnerability.

Mangrove-RESCUE addresses this need. Unique datasets will be collected in mangroves across three different continents, in collaboration with leading scientists. Bed level changes will be monitored at an unprecedented high resolution and linked with the hydrodynamic conditions, vegetation characteristics and sediment properties. A dynamic-equilibrium theory model will be developed to simulate sediment dynamics over time spans of up to a year. The incorporation of vegetation dynamics in this model will enable decadal predictions of mangrove evolution and resilience, through comprehensive scenario analyses. The safety provided by these predicted mangrove coastlines will be assessed in simulations of the flooding and erosion resulting from extreme flood events.

Mangrove-RESCUE aims to deliver a mechanistic understanding of mangrove resilience and the contribution of mangroves to coastal safety. This will yield practical tools to preserve and employ the long-term resilience of mangroves, thereby providing and enhancing safety in low-elevation coastal zones for current and future generations. These new insights on ecosystem-based coastal engineering will be applied in a case study, developing a coastal management strategy for a flood-prone area at a mangrove coast. Utilisation and dissemination is further embedded through active engagement of local stakeholders and NGOs. The outcomes of Mangrove-RESCUE will benefit both mangroves and humanity.

Figure 1 – Ban Ko Khiam village in Thailand benefits from its mangroves in many ways.