Rivers Course and Landforms

Results from erosion

WATCH THIS ------> http://www.bbc.co.uk/learningzone/clips/waterfalls-and-gorges-erosion-and-deposition/3239.html <------ it really helps about waterfalls gorges erosion and meanders!!! I made notes from it because it was really good just ignore the weird music :)

Waterfalls and gorges....How are they formed?

Hard rock lies on soft rock and begins to erode it, this forms a plunge pool debry from the fallen rock erodes the soft rock futher, this is called undercutting .The hard rock eventually collapes and the process repeats causing the waterfall to retreat up stream, this has formed a gorge.

Meanders and Oxbow lakes

Meanders and oxbow lakes are found in the middle course of a river.

• Water travels on the outside of a bend in a river and travels very fast, this causes the outside bank of the meander to be undercut creating a steep bank. Water on the inside bend is slower so doesn't have enough energy to carry its load, it therefore deposits the material forming a bigger bank on that side.This is called deposition.  
• Over time the meander horseshoe shape becomes tighter, until the outside bends become very close together. During a flood when the river has a higher discharge and more energy the ends join and the loop is cut-off from the main channel. The cut-off loop is called an Oxbow lake.watch the Diagram and it will make sense

 http://www.bbc.co.uk/schools/gcsebitesize/geography/water_rivers/river_landforms_rev2.shtml

levees and flood Plains

Flood Plain: This is the area beside a river in its lower course. As meanders move down the course of the river, they erode and widen the previously v-shaped valley and the river deposits material in the valley when it floods. Over time this fine material builds up to create a flood plain.

Levees: These are natural embankments/walls found along the sides of a river channel in the lower course. During a flood, the river deposits the heaviest material first, nearer the channel, which builds up into these banks over time.

So the difference is flood plains are built up with fine material whilst levees are built up with heavy, coarse material