2.b. Coastal landforms are inter-related and together make up characteristic landscapes Rhone Delta, France

Question 1

fphysical factors which influence the formation of landforms

Answer 1

This is a low-energy coastal environment:

1* The enclosed shape of the Mediterranean Sea means fetch
distances are relatively short in all directions. The longest fetch is
about 900 km from the SW, although that is interrupted by the
presence of the Balearic Islands.

2* The dominant wind direction (NW) typically has low wind speeds.

3* As a result of both of the above, waves tend to be low in height
and energy.

4* The high levels of sediment accumulation from river deposition
have created a gently sloping coastal landscape. Waves break
early on the shore and their energy is dissipated by the beach
and delta sediment.

Deposition was estimated to be 50 tonnes/min
in 1900.

5 The high deposition rate is due to the flocculation of clay particles. The
Mediterranean is very saline, and when salt water mixes with fresh
water, any clay particles present become adhesive and stick
together forming larger, heavier clumps which can no longer be
held in suspension.

Question 2

changes over time

Answer 2

climate change has led to rise in sea level of 2mm/yr since 1950
increased storm activity activity has lead to more erosion
coastal protection has introduced to combat coastal rtreat

Question 3

the inter-relationship of a range of landforms within the characteristic
landscape system

1. due

Answer 3

SCCAT

Cell 3 has converging longshore drift currents, and this
has resulted in the formation of onshore bars.

All along the coast, areas of lagoons (known locally as étangs) can be seen where
longshore drift has moved sand to create lagoons trapped behind the onshore bars and spits.

The delta is very gently sloping. The coastal beaches are narrow
with low dunes behind them.

Behind the dunes are the brackish ponds/lakes and lagoons. In the nearshore area
there are longshore bars where backwash removes sand and
deposits it, and between these there are longshore troughs.
Dunes form when the winds blow from the sea, and dry sand is
moved up the beach by saltation. The sand becomes trapped by
obstacles on the berm or the point of the highest spring tides.
Gradually these sand deposits will build up and become colonised
by plants, such as marram grass, which are adapted to salty
conditions and have long roots to help them survive on shifting
sands. The grasses trap more sand, forming an embryo dune.
These grow to form a ridge. Over time, dunes stabilise and the
plants colonising them change as soils become established. The
delta is covered by areas of brackish, saltwater marshes behind
sand dunes and around the edges of the étangs.