GCSE Geography Rivers- Landforms :D.

Upper Course

Main Process: Vertical Erosion

Landforms Found: V-Shaped Valleys, Interlocking Spurs, Waterfalls and Gorges.

Middle Course

Main Process: Lateral Erosion and Deposition

Landforms Found: Meanders, Ox-Bow lakes, Flood Plains and Levees

Lower Course (Mouth)

Main Process: Deposition

Landforms found: Deltas

For a Diagram, Paste this link into your browser's address bar :) :

http://cgz.e2bn.net/e2bn/leas/c99/schools/cgz/accounts/staff/rchambers/GeoBytes%20GCSE%20Blog%20Resources/Images/Rivers/v-shapedvalleys.gif

1) River begins to flow side to side (Zig Zag Fashion).

2) Valley Sides are weathered, Loose material falls into the river and is carried downstream

3) Hills with steep sides are formed at each side of the river. These are called "Interlocking Spurs".

4) A V-Shaped valley forms.

For a Diagram, Paste this link into your browser's address bar :) :

http://www.kented.org.uk/ngfl/subjects/geography/rivers/images/waterfalls%20and%20gorges.jpg

1) On a slope, the softer rock is usually under the harder rock.

2) As water runs along the slope, the softer rock erodes quicker than the harder rock, forming an extreme drop for water to run down. This is called a Waterfall.

4) Over time, the less resistant rock starts to erode at a much quicker rate than the harder rock, therefore undercutting the harder rock.

5) The harder rock begins to overhang, and when the overhang is big enough, the harder rock drops down onto the bed.

6) The force of this creates a plunge pool.

7) Over time, the waterfall retreats, creating a steep sided valley called a gorge :).

For a Diagram, Paste this link into your browser's address bar :) :

http://cgz.e2bn.net/e2bn/leas/c99/schools/cgz/accounts/staff/rchambers/GeoBytes%20GCSE%20Blog%20Resources/Images/Rivers/ox-bow_lake.gif

1) During a flood, the neck of land between the beginning and end of a meander is eroded.

2) The Meander becomes large and inefficient.

3) Soon, the river breaks through, and the rate of deposition around the outside of where the neck was increases.

4) The deposition continues until an oxbow lake is formed seperate to the river channel.

5) The Oxbow lake becomes a marsh over time, and eventually dries up completely.

For a Diagram, Paste this link into your browser's address bar :) :

http://www.belmont.sd62.bc.ca/teacher/geology12/photos/erosion-water/Meander_processes.jpg

A meander is a bend in a river.

1) Lateral erosion occurs due to the river flowing very fast on the outside.

2) Because the river is slowest on the inside, deposition occurs.

3) This creates a bend called a Meander.

Meanders usually occur where the river has to flow around an obstacle.

For a Diagram, Paste this link into your browser's address bar :) :

http://www.uwsp.edu/gEo/faculty/lemke/geomorphology/images/04_floodplain_deposits.gif

1) The river erodes laterally, wearing away the interlocking spurs and making the valley wider.

2) This makes flat land form (Flood Plains).

3) Alluvium (silt) is deposited on both sides of the river channel (Levees).

For a Diagram, Paste this link into your browser's address bar :) :

http://www.tulane.edu/~sanelson/images/delta.gif

A delta is a landform near the mouth of a river, where the water flows into another body (e.g. an estuary, a reservoir, or another river :P).

1) Deposition occurs at the mouth of the river, where the velocity of the river is very low.

2) The heaviest material is deposited first, and the lightest last.

3) Distributaries are formed as the main channel splits.

4) A delta is formed in layers

It is called a delta because it looks like the greek letter delta (which looks like a triangle).

They can only form under certain conditions:

• The sediment being transported must be large
• The sea must be shallow at the mouth
• The sea must have very small, weak currents.