Nile Delta CS

• How long is the River Nile?

  6650km
• What is the River Nile's catchment area?

  More than 3 million km2
• How does the River Nile influence the formation of landforms?

  1. Huge sediment load (sediment budget) = 30% clay, 40% silt and 30% fine sand
  2. Average annual sediment yield = 4.26 tonnes/ha/year (total = 91.3 million tonnes/year for the whole Blue Nile Basin in Ethiopia)
• What are the 3 distinct sub-units of the coastal plain and their characteristics?

  1. Foreshore plain-elongated ridges alternating with lagoons, salt marshes and alluvial deposits the depressions between them
  2. Frontal plain (south of foreshore plain) - scattered eroded limestone outcrops and clay deposits
  3. Sandy zone - variety of different sand formations (i.e. sheets, dunes and hummocks)
• What are the two distributaries of the Nile Delta?

  1. Rosetta
  2. Damietta
• How does wave action influence the delta?

  1. Wave action in the Mediterranean redistributes the sediment at the front of the delta
  2. The reworked sediment forms a series of curved barrier bars - close off segments of the Med Sea to form lagoons (turn into form of sub-environment and soon become filled with fine sediment)
  3. Low wave energy (low tidal range due to small entrance to Med - 2cm/year and small fetch) mean little erosion
• How does seabed topography influence the delta?

  1. Shallow continental shelf = friction so waves lose energy (deposition greater than erosion)
  2. Provides surface for accretion
• What is the prevailing wind and therefore wave direction?

  1. NW winds = waves coming from W, NW, N (55-60% of time)
  2. Waves come from NE (8% of time)
• Which physical factor is most important in influencing the delta?

  Large scale factors (i.e. seabed topography, sediment budget) most important in influencing the delta over millennia, but on a smaller, more local scale, other physical factors (i.e. winds, waves) influence the movement of sediment over time along the coastline
• What are the landforms east and west of Abu Qir headland?

  1. Beaches west contain long crescentic bar systems (associated rip currents and negligible LSD)
  2. Parallel longshore bars exist along delta extending from east of Abu Qir to Port Said (created by dominant eastward longshore current and associated LSD of sediment)
  3. Manzala Lagoon at Port Said (east)
• When was the Aswan High Dam built?

  1964
• How has the building of the dam influenced the delta?

  1. Imbalance created between erosion and accretion
  2. Rapid reduction in amount of sediment accreted (120m tonnes/year to only trace amounts today)
  3. Changes along NW Nile Delta with accelerated erosion and rates of coastal retreat as high as 148m/year
• What has also contributed to higher erosion rates?

  1. Rising sea levels in Med (1.2mm/year)
  2. Higher erosion rates as deeper water = larger waves with higher amounts of energy (reach further inland)