(Paper 1) River Channel Processes and Landofrms

Question 1

Abrasion

Answer 1

Is the wearing away of a riverbed and bank by the load which is being carried by the river

Question 2

Attrition

Answer 2

Is the wearing away of rocks and pebbles being carried by the river as they rub against one another making them smaller and rounder.

Question 3

Capacity

Answer 3

Refers to the total load that a stream can carry

Question 4

Competence

Answer 4

Refers to the size of the largest particle in the steam

Question 5

Discharge

Answer 5

Refers to the amount of water passing through a certain point and is referred to in cubic meters per second (CUMECS)

Question 6

Helicoidal flow

Answer 6

Is the flow of water in a corkscreweing motion, and is responsible for the formation of meanders.

Question 7

Hydraulic action

Answer 7

The process where water is forced into cracks in the river banks and this causes the sides to weaken an peices can break off.

Question 8

Laminar flow

Answer 8

Is when water flows parallel to the river bed

Question 9

Load

Answer 9

Is the particles of sediment and dissolved matter which is carried along by the river flow.

Question 10

Solution

Answer 10

Is the removal of chemical components from different rocks such as chalk these minerals are dissolved and carried in the river flow.

Question 11

turbulent flow

Answer 11

Is the aggressive flow that involves eddying and vertical movement

Question 12

Pools

Answer 12

Are the deep hollows scoured in the bed of a river usually found on the outer edge of meanders.

Question 13

Riffles

Answer 13

Small scale ridges formed of small pebbles and cobbles and is found between meanders in the straight section of a river.

Question 14

Upper Course

Answer 14

-steep gradient
-lower average velocity due to boulder obstruction and friction causing a turbulent flow
-narrow and shallow channel
-V shaped valley due to vertical erosion
-High levels of erosion/weathering of slopes freeze thaw occurrring at higher altitudes.

Question 15

Middle Course

Answer 15

-Gentle gradient
-Higher velocity
-Meanders, Gorges, Oxbow lake, Floodplains
-Smaller rocks, wider and deeper
-Flatter valley floor with bluffs.
-natural erosion, abrasion,attrition, deposition transportation.

Question 16

Lower course

Answer 16

-Very gentle gradient
-highest velocity until river reaches th mouth.
-mudflats, meanders, ox bow lakes, flood plains,leeves, river deltas.
-Very wide channel and deep with levees
-flat an wide with slopping bluffs
-deposition is a key process at the mouth forming river deltas etc

Question 17

Vertical erosion

Answer 17

occurs mainly in steep rocky upland areas. The geology of the river bed will affect the rate at which it erodes at.

Question 18

Lateral erosion

Answer 18

occurs where the river gradient is a lot less. The geology and strength of the bed and banks will affect the rate at which it erodes.

Question 19

Factors effecting erosion

Answer 19

-Load
-velocity
-gradient
-geology
-PH
-human impacts

Question 20

Suspension

Answer 20

form of river transportation small particles are carried suspended in the water.

Question 21

Traction

Answer 21

Transportation for large rocks and boulders which are rolled along the river bed being pulled by the river flow.

Question 22

Saltation

Answer 22

rocks which are to large to be transported in suspension are bounced along the rover bed.

Question 23

V shaped Valleys (upper course)

Answer 23

step 1
-Vertical erosion occurs as rocks and boulders are bounced an scraped along the river bed.
Step 2
-Weathering, as the river cuts downwards the sides are attacked by weathering. Overtime causes bits of soil and rock to loosen and break off.
Step 3
-Mass Movement, material slowly creeps down the slope and falls into the river and is carried away by the river flow.
-Step 4
- This ends in the creation of a V shaped valley.

Question 24

Pot Holes (upper course)

Answer 24

-Pebbles get caught in a hollow in the riverbed.
-Hollow would have formed from abrasion and or hydraulic action.
-The turbulent current and flow in the upper course swirled pebbles around.
-the pebbles are forced into hollows and the swirling moving from the turbulent flow causes a drilling motion making it wider and deeper.

Question 25

Waterfalls and Gorges (upper course)

Answer 25

Vetrtical erosion is heavily involved. Softer rock is eroded downwards due to vertical erosion an abrasion and hydraulic action.

Waterfalls an gorges tend to form where harder rock overlays softer rock.