Introduction
Coastal cities face escalating flood risks and ecological degradation as sea levels rise and impervious surfaces proliferate. Mangrove forests naturally attenuate wave energy and foster rich intertidal ecosystems through their buttressed root networks. This study translates mangrove root morphology into stepped timber terrace modules to enhance urban flood resilience while establishing biodiversity corridors in coastal urban waterfronts.
Methods
A parametric model of terrace geometry was developed in Rhino/Grasshopper, replicating key root buttress angles and spacings observed in Rhizophora species. Computational fluid dynamics (CFD) simulations in OpenFOAM evaluated energy dissipation, flow velocity reduction, and sediment transport under hydrographs representing 1-in-10-year and 1-in-100-year storm events. Pilot terraces—each 5 m wide, 0.6 m high, and composed of sustainably harvested glulam planks—were installed along a tidal creek in Lusaka’s simulated coastal analog. Pre- and post-installation topographic surveys measured bed scour and deposition, and biodiversity assessments employed quadrat sampling of benthic invertebrates and opportunistic fish counts over a six-month tidal cycle.
Results
CFD results indicated up to a 45% reduction in peak flow velocity and a 30% increase in upstream water stage during extreme events, compared with unmodified embankments. Sediment transport models projected a 22% rise in depositional volume behind terraces, corroborated by field surveys showing an average 18 mm sediment accretion per tidal cycle. Biodiversity surveys recorded a 65% increase in invertebrate species richness and a 40% rise in juvenile fish abundance within terrace zones versus control sites. Structural monitoring confirmed that the timber modules endured cyclic tidal loading without significant deformation or joint fatigue over six months.
Conclusions
Mangrove-inspired timber terraces effectively dissipate flood energy, promote sediment accumulation, and create functional habitat corridors in urban coastal contexts. The modular, bioinspired design leverages sustainable timber resources and parametric modeling to deliver scalable, low-impact interventions. Future research will examine long-term durability, integration with green infrastructure networks, and social acceptance in diverse urban settings.
