Thursday, April 23, 2009
I will be doing the blog posts on two lessons, last week’s (14th April) and today (22nd April).Last week’s lesson was a rather short lesson. Basically, we learnt about a river, that a river has energy, and that various energies affect how a river behaves or looks like. Also, we discussed about the different factors that affects a river’s energy.
A river’s energy is mainly contributed by:
1. Volume
2. Velocity
The higher the volume and velocity of a river, the more energy a river has.
So what affects the velocity of a river? Basically, there are mainly two factors involved, namely Gravity and Friction, in other words, Channel Shape.
Moving on to today's lesson, we learnt about the different features and formations of rivers , about the Hjulstorm curve works and how velocity is a vital component in determining how a river behaves.
Firstly,
What are the different sections of a river?
What is Erosion?Erosion is defined as the picking up and removal of material.
There are mainly five processes affecting erosion:
1. Corrosion
2. Abrasion
3. Hydraulic action
4. Solution
5. Attrition
Hjulstrom Curve
Area between erosion and deposition velocity: transportation of load occurs
Area above erosion velocity: erosion of load will occur
Area below deposition (fall) velocity: deposition of load occurs
Note: erosion and deposition velocity values vary with load!
Ok then, i’m done
Darryl
P.S. I apologize for the low quality pictures