2.b.LE Coastal landforms are inter-related and together make up characteristic landscapes.

Question 1

background of the Nile Delta

Answer 1

in Egypt

one of the longest rivers in the world (6,650km) -> therefore has a large sediment load

it has 2 main distributes -> which are its main sediment source
-> as it is split -> it has less energy

rate of deposition has exceeded rate of erosion for 3000 years

Question 2

physical factors that influence the formation of landforms

Answer 2

wave energy
sediment supply
(topography + currents)

Question 3

how wave energy influences the formation of landforms

Answer 3

Short fetch of 750km -> low energy constructive waves -> high rates of deposition

NW prevailing winds from Mediterranean -> means direction of LSD is East (-> formation of on-shore bar)

Low tidal range (2m)

Rising Mediterranean Sea levels of 1.2mm per year = higher erosion as deeper waters produce larger waves with greater energy

Question 4

how sediment supply influences the formation of landforms

Answer 4

In 1964 -> they built a dam -> preventing transportation of fluvial sediment ->
Went from 120 mil tonnes/yr to basically nothing -> landforms put in a deficit -> as rate of erosion exceeds rate of accretion -> coastline retreating 148m/yr

Clay, slit + fine sand -> with little resistance to erosion -> build up on the beaches from constructive waves

Question 5

how does topography + currents influence the formation of landforms

Answer 5

topography -
shallow continental shelf –> accumulation of sediment –> formation of delta

currents -
localised rip currents –> creates landforms –> crescentic bars

Question 6

the interrelationship of landforms

Answer 6

Damietta headland reduces wave energy -> creating a sheltered environment -> allowing LSD to deposit sediment -> forming a Damietta on-shore bar
This then cuts off the sea -> forming Manzala lagoon

Fluvial sediment used to come from the distributaries -> to form the crescentic bars -> however this sediment was moved via aolian transportation -> to form Gamsa sand dune
Over time -> less fluvial sediment -> has make the sand dunes smaller

LSD redistributes sediment -> changing size and shape of sediment and therefore landforms as well as creating new landforms

Some landforms less inter-related e.g. to the West of Abu Qir headland, crescentic bar systems on the beaches influenced by local rip currents rather than longshore drift- less affected by sediment transportation

Question 7

how and why do these systems change over time

Answer 7

from millennia-
climate change->
Rising Mediterranean sea levels of 1.2mm per year

-> more erosion -> as deeper waters produce larger waves with greater energy -> landforms vulnerable -> coastal retreat

-> onshore bars may be breached
-> the lagoons could flood + inundated the delta with sea water -> having socio economic impacts -> 60% loss of farmland by 2100 + loss of fresh drinking water

to seconds-
onshore bar may be breached -> due to rising sea levels

seasonal variations-
in summer ->
winds transport sediment from delta via suspension -> to create curved barrier bars e.g. from Rosetta distributary to Port Said

in winter ->
storm conditions -> destructive waves -> more erosion of delta -> this sediment is then transported to offshore zones -> to create sandbars