Estuarine Mangrove Squeeze In The Mekong Delta.

Son Truong, Qinghua Ye, Marcel Stive

Tuesday 30 june 2015

12:45 - 12:48h at Asia (level 0)

Themes: (T) Managing deltas, (ST) Impacts of urbanization and land reclamation, Poster pitches

Parallel session: Poster pitches: 5C. Deltas - Impacts

In the Mekong Delta Estuaries (MDES), due to the continuously increasing extension of local agriculture and fish farming in many regions, mangroves have degraded into a very narrow strip of sometimes less than 50 m in width. River banks at those locations are often suffering from erosion and are unstable. Many efforts have been undertaken to protect the river banks as well as to maintain the mangrove forests, but until now very limited results have been achieved. The erosion trend is anticipated to continuously increase in the near future. The threat to the existence of the coastal mangroves or tidal wetland habitats caused by the compound impacts of the human-induced and sea-level rise induced is increasingly recognized as term “squeeze”. While the “squeeze” issue for coasts has been increasingly recognized, the similarity for mangroves in estuary area is less well acknowledged. The difference is that while the main hydrodynamic forces effect on mangroves at coastal area are waves, mangroves in estuaries mainly affected by the flow, i.e. flow from tidal action and flow from river discharge. This implies a similarity with the hydrodynamics of floodplain vegetated channels. By analyzing the data from literature and from satellite images together with the application of the rigid 3D Vegetation in Delft3D-FLOW, the impacts of local fish-farming construction on the hydrodynamic of riverine mangrove forest in MDES is being studied. Results reveal a critical width required for the stable development of the riverine mangrove forest in MDES. Besides, flow penetration from the main channel into the mangrove regions play an important role and cannot be neglected in understanding the behaviors of riverine mangrove towards changes in landward boundary conditions.