interrelationship low energy

• How much sediment is moved W to E every year ?

  1,000,000 cm3 per year

  Due to longshore drift and offshore currents
• Abu Quir Headland and Bay

  Formed due to limestone ridges

  Bays form due to the east as geology is less resistant
• Rosetta Promontary

  Result of deposition where Nile enters the Mediterranean

  NW winds means promontory is exposed to incoming waves causing erosion - inputs sediment

  Longshore drift and currents carry eroded sediment to the east leading to deposition - spits and bars + burullus lagoon and salt marshes

  Promontory provides shelter and a low energy environment to the east where drift-aligned beaches can form
• Damietta Promontory

  Built up by fluvial sediment from the Nile

  Eroded as it faces the NW winds

  Material transferred east to build up spits and bars across the Manzala lagoon

  Spits and bars have allowed for salt marshes to form
• Burullus Lagoon

  Longshore drift and ocean currents move sediment west to east along the delta front - leading to spits and bars across the lagoon

  Lagoon is getting smaller as the barrier bar is preventing access to the sea causing evaporation to dominate the equilibrium as well as salinisation and vegetation build ups
• Manzala lagoon

  longshore drift and deposition to the east of the nile distributaries has led to growth of spits and bars across the manzala lagoon and associated salt marshes

  still has connection to the sea
• Gamasca

  Beach

  Increased deposition in Gamasca due to NW aeolian transport and deposition and the presence of the low energy sheltered bay.

  The sediment is moved and deposited in the sheltered water around gamasca due to low-energy constructive waves
• Parallel sand bars

  Generated by eastward longshore current and longshore drift between Abu Qir bay heading east to port said
• Dune systems

  Onshore winds blow sediment in land resulting in the development of sand dune systems

  Much if this is transported from neighbouring systems in the west via aeolian processes.
• crescentic sand bars

  less drift dominated process west of Abu Qir headland due to localised rip currents and reduced drift

  more swash dominated
• Long term changes

  7 distributaries to 2

  features will dissapear more quickly than they form due to the environment becoming erosional and less sediment in rivers
• Short term changes

  Crescentic sand bars - formed due to rip tides (change very quickly )
• Seasonal changes

  Winter = higher winds and more storms = more rates of erosion

  Dune systems more affected in winter due to higher winds

  Burullus lagoon facing salinisation and becoming a marsh as it’s being cut off from the sea.
• Climatic changes

  Natural fluctuations in rainfall in Ethiopian highlands has led to reduction in discharge and sediment load.

  Sea levels rise cause more access to the delta increasing rates of erosion
• What did the building of the Aswan High Dam cause?

  98% reduction in sediment deposited in Lake Nassar
• What does a 1m rise in sea levels cause for the delta?

  15% loss