The Nile Delta

Question 1

Give some background?

Answer 1

It is a low energy coastal environment.
Rates of fluvial deposition have exceeded marine erosion for over 3000 years.
The situation is changing due to the influence of human and physical factors.

Question 2

How long is the River Nile?

Answer 2

6650km

Question 3

What is the River Niles catchment area?

Answer 3

3million km^3

Question 4

What is the mean rain fall in the catchment?

Answer 4

600mm average a year

Question 5

What is the average discharge?

Answer 5

3000m^3 per second, one of the lowest of the great rivers.

Question 6

What is the annual sediment yield?

Answer 6

4. 26t/ha/year

91. 3 million for whole Blue Nile basin

Question 7

What is the distribution of the Niles sediment load?

Answer 7

30% clay
40% silt
30% fine sand

Question 8

What is the coastal plain?

Answer 8

The Northern part of the Nile Delta, runs parallel to the Mediterranean coastline.

Question 9

What are the 3 Subunits of the coastline?

Answer 9

Foreshore plain
Frontal plain
Sandy zone

Question 10

What is the Foreshore Plain?

Answer 10

Characterised by elongated ridges.
Runs parallel to the present shoreline.
Alternates with lagoons, salt marshes and alluvial deposits between them.

Question 11

What is the Frontal Plain?

Answer 11

Located south of the foreshore plain.

scattered eroded limestone outcrops and clay deposits.

Question 12

What is the Sandy Zone?

Answer 12

Comprised of different sand formations such as sheets, dunes and hummocks.

Question 13

How do the distributries split?

Answer 13

Splits at Cairo 160km inland into distributries which fan out over the whole delta.

Question 14

What happened before the Aswan High Dam?

Answer 14

Before the construction in 1964 the Niles annual flood would cover t much of the delta in a thick layer of silty mud.

Question 15

How do barrier bars form?

Answer 15

Wave action in the Med redistributes the sediment in front of the delta, the reworked sediment forms a series of curved barrier bars.

Question 16

What is the effect of barrier bars?

Answer 16

They close of segments of the delta to the Mew, forming lagoon which then fill with fine sediment.

Question 17

What is the wind like?

Answer 17

Prevailing Northwesterly wind, enhances the constant eastward movement of water and sediment.
Estimated surface velocity of 10cm/s in summer.
4.5cm/s in Autumn
23cm/s in Winter
Wind leads to waves from the Northwest 60% of the time and NE 8%.

Question 18

What is the main landform?

Answer 18

Different types of sand bars.

Question 19

What are the different types of bars?

Answer 19

West of Abu Qir has long cresentic bar systems associated with rip currents and negligible LSD.
East of Abu Qir has long parallel bars generated by dominant eastward longshore current and associated LSD.

Question 20

What are the effects of the Aswan High Dam?

Answer 20

An imbalance between erosion and accretion
Rapid reduction in the ammount of sediment accreted, from 120 million tonnes to trace amounts.
NW shoreline has accelerated erosion rates at 148m/year.
Rising Med sea levels of 1.2mm/year have contributed to higher erosion rates.
Deeper water causes larger waves to reach further inland.