THUKELA  ESTUARY: Hydrodynamics and mouth dynamics 

According to Ref.1 (1978),  the sandbar has a 700 m stable component on the floodplain (carrying a coastal dune forest) extending in a generally northern direction. There is also a 700 m unstable component without vegetation that forms across the mouth. This bar is periodically removed by flood discharges. During flood conditions an offshore bar is formed, directing floodwater into the sea in a southerly direction. It is unlikely that mouth closure occurred during virgin conditions. More frequent mouth closures recorded in recent times (for only a few days at a time) are probably due to the significant abstraction of water from the system via interbasin transfer schemes to the Gauteng province. However, under future transfer schemes and runoff scenarios it is predicted that a drastic increase in mouth closure conditions will occur, for prolonged periods of up to 4 or 5 months.  (Ref.3)