hey people! sorry for the late posting :O

i am going to talk about river landform as stated in the post that ailin did (:

so... river landforms?:D

at the Upper course, the landform present are potholes and waterfall.

a) potholes:

it is a depression on the river bed carved our of solid rock.

it is formed by a kind of drilling-action causes by the rock sediments caught in the current and also by the contraction and expansion of water.
they are commonly found below waterfalls or rapids where hydraullic action is a significant process (remember? it's learn in erosion!!)

b) waterfall

A waterfall is a place where flowing water rapidly drops in elevation as it flows over a steep region or a cliff.

form where the channel slope becomes steeper or is composed of varying bands of soft and hard rock. erosion (occur when the volume or speed of the flow of water increased), hydraulic action and abrasion will cause the water to fall from a higher level to a lower level.

at the middle course, the landforms present are meanders and oxbow lakes.

c) meanders

A meander is formed when the moving water in a river erodes the outer banks and widens its valley. erosion and deposition occurs at the bend of the river. the speed is greater on the outside of the bend therefore erosion occurs on the outside while deposition on the inside.

d) Oxbow lakes

An oxbow lake is a U-shaped body of water formed when a wide meander from the main stem of a river is cut off to create a lake
as the opposite bends erode towards echother, the neck of a meander will get progressively narrower until, during a period ofhigh discharge, the river will cut through to form an oxbow lake.

at the upper course, the landforms present are Floodplains and levees.

e) floodplains

they are mosly flat land bordering a river that is subjected to periodic flooding.
They are formed by the gradually flooding and draining of a river. So, every time a river floods the silt it carries is depositied either sides of its banks, with eventually build up a flat layer of aluvinum, which is a flood plain.

f) levee

When a river carrying sediment overflows it's banks the coarsest sediment is dropped first as the river no longer has the energy to carry it. The coarse material forms a small natural embankment (levee) along the edge of the river channel. The coarse material forms a small natural embankment (levee) along the edge of the river channel. The finer material is carried further away from the river channel across the floodplain and is deposited here. Over time if flooding occurs regularly the levees will become naturally higher.

hope these helps everyone in the understand of river formation :D

and really sorry for the late posting!!

yijin (15) jh403!:D