Today (24/4) Ms Lin walked into class.

and basically covered some new content that was essential to the following lesson's discussion.

Upper Course	Middle Course	Lower Course
V-shaped Valley	Wider flatter valley	Wider flatter valley
Mass movements	Wider and deeper channel Alluvial(loose material like sand/sediments)	Wider and deeper channel Alluvial(loose material like sand/sediments)
Vertical erosion (Bedrock[hard rocks] channel)	Increased sinuosity	Floodplains and levees

THEN we went onto River Processes and sedimental transportation

Ways that sediments can be transported

1. Traction - heaviest material that rolls along river bed requires the most energy to carry

2. Saltation - Rocks bounce 

3. Suspension - Small particles like salt/clay/sand that is carried with water through turbulent flow. The MAIN form of sediment transfer

4. Solution - Minerals dissolved

Processes of erosion

The excess kilojoules of a river is harnessed to erode, the process of picking up and removal of material.

 

	Corrasion/Abrasion	Hydraulic Action	Solution	Attrition
Targets	Bedrock	Cracks	Bedrock	Sediment load
Nature	Drilling/sand paper	Pressure	Chemical	Impact
Outcome	Vertical/lateral erosion	Collapsed bank		Smaller/rounder

Erosion of RIVER CHANNEL

Sandpaper - the sediment load rubs against load, in collision

Hydraulic Action - Water enters the holes/cracks, which results in increased pressure. The air bubbles burst after heavy compression

Attrition - High pressure just result in impaction, collision 

There was this Velocity-Particle grain size(diameter) graph shown which shows the velocity needed to carry a certain coarse material. However, the values of the graph cannot be considered seriously because not all particles are round.

So after these mundane content we started looking at pictures! Such as deltas...meanders...etc. and apply our knowledge!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

taro