Case study for low energy - Nile delta Flashcards
Nile delta
Displays many typical features of a low-energy environment
Rates of fluvial deposits has exceeded rates of marine erosion for over 3000 years
Three distinct subunit - foreshore plain, frontal plain, sandy zone
before 1964 the annual flood briefly covered much of the delta and deposited a thick layer of silty mud
4m at aswan
9.6m in cairo
River nile
6650km in length
3 million km3 catchment area
Mean annual rainfall in the catchment is 600mm
Average discharge is 3000 m/s (this is one of the lowest)
Annual yield sediment os 4.26t/a/year
91.3 million tonnes for the whole blue nile basin in Ethiopia
Nile deltas foreshore plain
Elongated ridges - running parallel to the coastline
Alternating lagoons, slat marshes and alluvial deposits
Nile delta frontal plain
Scattered eroded limestone outcrops and clay deposits
Nile delta sandy plain
Composed of a variety of sand formations
Sheets
Dunes
Hummocks
Delta lobes
Two of the large distributaries have been built on major lobes extending beyond the general front of the delta
Wave action in the mediterranean distributaries the sediment a the front of the delta
The sediment former curved barrier bars which close off segments of the mediterranean sea to from lagoons, these lagoons fill with sediment
Coastal landforms
Underwater sand bars
Long shaped crescentic bar systems
Parallel longshore bars
Changes to the sediment budget
Since the building of the Aswan high dam an imbalance had been created
the erosion is greater than the accretion
Rapid reduction in the amount of sediment accreted
120 million t/year to only trace amount
Changes to sea levels
Rising sea levels in the mediterranean of 1.2mm/year has also contributed to higher erosion rates
Deeper water produces larger waves with higher amounts of energy
These wave reach further inland
