Geog Final

Front 1

River

Back 1

A river is water in a channel moving downhill under the influence of gravity

Front 2

Drainage basin

Back 2

The areas of land drained by a river system

Front 3

4 things a river will always try and do

Back 3

1. Flow downhill

2. Find the easiest way downhill

3. Carry the most sediment

4. Reduce its gradient

Front 4

4 features that can describe a river

Back 4

1. The number, size and shape of the channel

2. Discharge

3. Sediment load

Gradient

Front 5

Size and shape

Back 5

Based on measurements of width and depth w/d

Front 6

Discharge

Back 6

The volume of water moving in a channel in a given time

Q= W x D x V

Front 7

Sediment load

Back 7

This is the sediment that is moving or may move if discharge increases

Front 8

Gradient

Back 8

This is the slope of the channel bottom

Front 9

Water flow in a channel

Back 9

Water velocity will vary depending upon proximity to the channel sides and bottom

Fastest moving water is found at the top centre. Zero at the sides and bottom due to friction

Front 10

Types of flow in a river

Back 10

1. Laminar

2. Turbulent

Front 11

Laminar flow

Back 11

The water moves down stream as a series of parallel layers with no vertical or lateral mixing. Rare in nature

Front 12

Turbulent flow

Back 12

Water follows an irregular path. Significant vertical and lateral mixing. Turbulence is the result of friction with the bottom and within the water

Front 13

River processes

Back 13

1. Weathering

2. Erosion

3. Transport

4. Deposition

Front 14

Weathering

Back 14

The disintegration of matter - rocks and minerals - by physical and chemical means

Front 15

Erosion

Back 15

In a river, sediment is set in motion in three different ways

Front 16

3 ways sediment is set in motion in a river

Back 16

1. Physical impact of moving water

2. Physical impact of other moving sediment

3. Hydraulic lift

Front 17

Hydraulic lift

Back 17

A process whereby changes in water velocity and pressure around a grain cause it to move more

Front 18

Abrasion

Back 18

Physical impact of moving water and sediment eroding sediment in a river

Front 19

Transport

Back 19

The way sediment moves once it is in motion

Front 20

4 ways sediment in a river can be transported

Back 20

1. Solution

2. Suspension

3. Saltation

4. Traction

Front 21

Solution

Back 21

Dissolved elements and molecules in the water

Front 22

Suspension

Back 22

The finest solid particles that are carried in the water column that rarely make contact with the bottom

Front 23

Saltation

Back 23

Large solid particles that bounce along the bottom. They make frequent short term contract with the bottom

Front 24

Traction

Back 24

The largest solid particles that roll or slide along the bottom. These grains are in constant contact with the bottom

Front 25

Bed load

Back 25

Traction and salutation together

Front 26

Deposition

Back 26

Moving sediment in a river is deposited when water velocity drops. It also takes place when molecules or elements in solution precipitate to form new solid minerals

Front 27

Types of rivers

Back 27

1. Meandering

2. Braided

Front 28

Thalweg

Back 28

The line that shows where the deepest, fastest water is