Different fates of the Yangtze and Mississippi deltaic wetlands under similar riverine sediment decline and sea-level rise

摘要: Abstract The Yangtze River has experienced a sharp sediment decrease as result of extensive dam constructions since the 1980s, similar to decline in Mississippi 1950s. Historical land losses Delta have been reported extensively, but this issue is still under debate. Here we presented morphological responses deltaic wetlands with comparison hydrodynamic forces and deltas. We found that continued their expansion even after 2003 when Three Gorges Dam began operation, contrast historical scenario Mississippi. Based on observations at water depth around 10 m both open subaqueous deltas, bed shear stresses caused by waves currents (τcw) during neap spring tides were 0.18–0.30 N/m2 0.09–0.10 N/m2 fair weather conditions. periods τcw > τcr (the critical stress for erosion) occupied average 80% tidal cycle only 47% Delta. rates relative sea-level rise riverine these two deltas are similar, sediment-supply capacity from Yangtze's delta much larger than Thus, infer loss Delta, stand good opportunity survive years decades aid abundant due higher seabed erodibility stronger coastal hydrodynamics.