Water Hyacinth Geotextiles as a Nature-Based Solution for Riverbank Protection in the Vietnamese Mekong Delta

Riverbank erosion in the Vietnamese Mekong Delta (VMD) poses a serious threat to agricultural lands, infrastructure, and local communities. Conventional protective measures, such as synthetic geotextiles and concrete revetments, are often costly and environmentally disruptive. This study investigates the potential of Eichhornia crassipes, a widely available invasive species, commonly known as water hyacinth (WH), to produce biodegradable geotextiles as a low-cost, nature-based solution (NbS) for small-scale riverbank protection. It is the first to test minimally processed WH mats under simulated tidal conditions in the VMD. Laboratory experiments were conducted to evaluate the geotextile’s (1) sediment retention capacity, (2) wave energy reduction, and (3) mechanical durability under wet–dry cycles. Results show that the WH geotextile effectively reduced sediment resuspension, decreasing turbidity levels from 800 FTU (unprotected scenario) to below 50 FTU. The geotextile also attenuated wave energy, reducing significant wave heights by approximately 35–40%. Mechanical testing revealed that the fish bone weaving pattern with adhesive coating achieved the highest tensile strength (8.36 kN/m after 12 wet–dry cycles), while uncoated samples demonstrated higher elongation (up to 61.67%), providing greater flexibility. These demonstrate the feasibility of WH geotextiles as a scalable nature-based solution for erosion-prone tropical deltas. Future studies should focus on field-scale validation, biodegradation rates, and performance optimization for long-term applications.