Nile Delta Flashcards
Where is the Nile Delta?
It is in the north east of Egypt, north of Cairo and west of the Suez Canal, protruding into the southern Mediterranean Ocean.
How much land does the Nile Delta cover, and how many people live on the delta?
It covers about 20,000km^2, covering 240km of mediterranean coastline and going 160km inland, and about 40 million people live on the delta, giving it a density of about 2000 people per km^2.
What type of delta is the Nile Delta and what does this mean?
It is an Arcuate delta, which means a smoother coastline due to greater mixing of fresh and saltwater, so fluvial sediment settles closer to shore. (FLOCCULATION).
What is the circulation of currents in the Mediterranean, and what does this mean for the Nile Delta?
The circulation of current is from West to East, travelling anti-clockwise, which causes large volumes of sediment on the coast to move towards the East in accordance with longshore drift.
How large is the tidal range at the Nile Delta?
The tidal range is about 30cm.
Why is the tidal range low?
The tidal range is low because the Nile Delta is almost completely separated from the Atlantic, and so only subject to the effects of tides in the smaller Mediterranean sea.
What is the direction of prevailing winds at the Nile Delta?
North-North Westerly Prevailing winds.
What is the typical fetch for waves at the Nile Delta, and what is the resut of this?
Typically 550km but can get up to 2000km in places, resulting in low energy waves.
How did the Nile Delta form and when did it begin?
The Nile Delta began to form around 6000 years ago after sea levels stabilised following the flandrian transgression. It formed due to a low tidal range and wave energy, facilitating the alluvial sediment to steadily accumulate above the high tide level for over 3000 years.
What are some key facts about the Nile? (e.g. length, drainage basin, sediment)
> 6650km long
3 million km^2 drainage basin
Water is brought from two main branches from Ethiopia and Rwanda.
91.3 million tonnes of sediment is brought in per year by the Nile
What is the proportion of clay/ silt/ sand in the Nile Delta’s sediment?
30% clay, 40% silt, 30% sand.
How has the contruction of the Aswan Dam affected the Nile Delta
It has reduced overall flow and discharge in the river, which means it is able to carry less sediment, which in turn reduces sediment inputs to the Nile Delta, causing coastal retreat at the delta, as the rate of sediment removal exceeds the rate of accumulation. DYNAMIC EQUILIBRIUM –> POSITIVE FEEDBACK
What kind of coastal landforms are present on the Nile Delta?
Beaches
Barrier Bars and Lagoons
Sand Dunes
Sabkhas
What are typical characteristics of beaches found on the Delta?
They are composed of reworked alluvial deposits, usually of sediment such as sand ( < 0.2mm) and clay ( < 0.01mm) resulting in a beach of very low gradient (2*)
What are some examples of barrier bars and lagoons and how have they formed?
Lagoons present on the delta include Lake Manzala, Lake Idku and Lake Burullus.
They are made from reworked alluvial sand deposits
They have formed as a result of the eastward movement of sediment (longshore drift) due to the North Westerly prevailing winds.
