nile delta

• What is a delta?

  a depositional landform formed as sediment is deposited at the mouth of a river

  the river Nile has formed the Nile delta at its mouth, as the river flows into the Mediterranean
• As sea levels rise and protective offshore bars are eroded, 3.3% of the delta land area will be lost
• What is the Nile delta responsible for?

  the fertile agricultural land in this part of Egypt

  it also adds sediment to the Mediterranean, which builds up beaches and adds nutrients
• erosion rates at the Rosetta, where one of the main delta branches of the river meets the sea, jumped from 20m per year to over 200m per year as the delta was starved of sediment
• The coastline of Alexandria faces erosion due to various factors, including sea level rise, coastal development, and natural processes.

  This erosion threatens the stability of beachfront properties and reduces their desirability among buyers concerned about long-term property value and safety.

  As sea levels rise and offshore bars are eroded, 3.3% of the delta land area will be lost.

  The delta area is where 95% of Egypt's population live.
• sediment volume fell from 130 million tonnes to about 15 million tonnes
• following construction of the Aswan High Dam on the River Nile in the 1960s, river discharge fell from about 35 billion m3 per year to around 10 billion m3

  prevents delta from being replenished
• What problems can be caused by deltas?

  causes subsidence due to accretion of land- puts additional weight onto the crust - isostatic change
• A 2015 study classified 32.4% of the Nile Delta coast as highly vulnerable with only 26% as low vulnerability
• Summary:

  • Aswan High Dam completed in 1968
  • river discharge fell from 35 billion m^3 to 10 billion m^3 and sediment fell from 130 million tonnes to 15 million tonnes due to water withdrawals for industry, farming behind the dam and sediment being trapped by the reservoir and the dam
  • increased erosion rates
  • heavier demand for water use upstream, predicted 70% decrease in the volume of Nile water reaching the Delta
• Where is the Nile Delta?


  in northern Egypt

  it is home to 50% of the country's population
• what is the Nile Delta considered to be?


  a densely populated coastal area
• What city sits on the northwest edge of the Nile Delta?

  Alexandria

  this is one of the largest cities in Egypt, with a population over 5.4 million
• what is a delta?


  A triangular area of sediment deposited at the mouth of a river.
• why is its coastline under threat?

  due to rising sea level in the Mediterranean and high amounts of erosion
• what is the rising sea level doing?


  low-lying areas at the front of the delta are becoming more saline

  saltwater intrusion is occurring and floods leave salt deposits on the land
• what impacts does the saltwater intrusion from rising sea levels have?

  Freshwater aquifers are becoming contaminated with salt, reducing the availability of freshwater for drinking

  freshwater lakes and lagoons are now too salty to use for irrigation
• an impact on agriculture from saltwater intrusion?


  Crops struggle to grow in saline soils, leading to reduced agricultural productivity.

  Farmers may have to abandon certain crops and land areas, impacting food security and livelihoods.
• impact on fishing industry from salt-water intrusion?


  some fish species are unable to survive in the water in the delta, threatening the future of the fishing industry
• why has transportation of sediment along the Nile Delta reduced?


  due to the building of the Aswan Dam in 1970

  before then, 9.5 million tonnes of sediment washed down the Nile and onto the delta every year

  now, fluvial sediment coming down the River Nile is not replacing the eroded material from the coast of the delta
• what does the Aswan Delta do?


  it holds back over 98% of the Nile's sediment in the Lake Nassar
• what is causing the Nile Delta to retreat?


  the combination of rising sea level and low levels of sediment deposition from the River Nile

  this has caused the Nile Delta to retreat up to 140m a year in some places