Definitions For Rivers Topic

Question 1

What is the watershed?

Answer 1

An area of ridge or land that separates waters flowing into different rivers, drainage basins or seas.

Question 2

What is evapotranspiration?

Answer 2

The process by which water is transferred from the land to the atmosphere by evaporation from the soul and other surfaces and by transpiration from plants.

Question 3

Define precipitation.

Answer 3

Rain, snow, sleet or hail that falls to or condensed on the ground.

Question 4

What is interception storage?

Answer 4

When precipitation from an event falls on vegetation which shelters the underlying ground and stops it from reaching the ground.

Question 5

What is through fall?

Answer 5

The part of rain fall or other precipitation that falls to the forest floor through from the canopy.

Question 6

What is stem flow?

Answer 6

The flow of intercepted water down the trunk or stem of a plant.

Question 7

What is unimpeded fall?

Answer 7

When precipitation reaches the ground without being intercepted and with no obstructions.

Question 8

Define infiltration.

Answer 8

The process by which water on the ground surface enters the soil.

Question 9

What is overland flow?

Answer 9

The movement of water over the land, downslope towards the surface of a body of water.

Question 10

Define percolation.

Answer 10

The process of a liquid slowly passing through a filter. When water flows through the ground through permeable rock.

Question 11

What is through flow?

Answer 11

When water moved downhill slowly through the soil.

Question 12

What is river run off?

Answer 12

Flow of rainwater away from where it has fallen.

Question 13

What is the water balance?

Answer 13

Shows the balance of water going into and out of a drainage basin.

Question 14

What is river discharge?

Answer 14

The volume of water passing a measuring point or gauging station in a river in a given time.

Question 15

What is base flow?

Answer 15

The portion of stream flow that comes from ‘the sum of deep subsurface flow and delayed shallow subsurface flow’.

Question 16

Define ‘runoff’.

Answer 16

All the water that enters a river and eventually flows out of the drama be basin. Can be quantified by measuring the discharge of a river.

Question 17

What is a water budget graph?

Answer 17

A graph that shows the water budget of a particular location. Shows the relationship between temperature, precipitation and evaporation over a year.

Question 18

What is a hydrograph?

Answer 18

A graph showing the rate of discharge versus time past a specific point in a river.

Question 19

What is a storm hydrograph?

Answer 19

Shows variation in a rivers discharge over a short period of time- usually during a rainstorm.

Question 20

What is the rising limb?

Answer 20

The part of a hydrograph that shows the rising floodwater in a river.

Question 21

What is peak flow/ discharge?

Answer 21

The highest amount of discharge in the river shown on a hydrograph.

Question 22

What is the recession limb?

Answer 22

Shows the fall discharge back to base levels on a hydrograph.

Question 23

Define ‘lag time’.

Answer 23

The time difference between peak rainfall and peak discharge shown on a hydrograph.

Question 24

What is storm flow?

Answer 24

Overland flow + through flow (hydrograph).

Question 25

Define erosion.

Answer 25

The process of being broken down by wing, water or other natural processes. The gradual destruction or diminution or something.

Question 26

Define the word ‘deposition’.

Answer 26

The laying down of solid material, in the form of sediment, on the bed of a river or on the sea floor.

Question 27

Define ‘transportation’.

Answer 27

The movement of particles from the place they were eroded to the place they’re deposited.

Question 28

What is a drainage basin?

Answer 28

An area of land drained by a river and its tributaries.

Question 29

What is ‘hydraulic action’?

Answer 29

It is the movement of large, unconsolidated material from the river bed, particularly sand like particles, due to the frictional drag of the moving water on the sediment of the channel bed.

Question 30

What is abrasion?

Answer 30

The reduction in size of the rivers load particles due to the rubbing and hurting together of particles, causing more rounded and smaller particles to be created.

Question 31

What is corrosion erosion?

Answer 31

When the minerals in rocks are dissolved by weak acids in the rivers water and therefore carried away in solution. Most active in carbonate rocks.

Question 32

Describe what abrasion erosion is.

Answer 32

It is the scraping, rubbing and scouring of the rivers load along the river bed and banks, leading to the banks and the bed f the river channel being wore away.

Question 33

What is cavitation erosion?

Answer 33

When air bubbles in turbulent stretches of water implode, causing shock waves that break pieces of rock off the banks and bed.

Question 34

Describe what head ward erosion is.

Answer 34

It’s the process of making the river channel longer by erosion. It happens at a rivers source as through flow and surface run off causes erosion at the point where water enters the river channel.

Question 35

Describe what vertical erosion is.

Answer 35

Erosion that erodes the rivers bed to make the river deeper. Predominantly happens in the rivers upper course where there is lots of energy.

Question 36

What is lateral erosion?

Answer 36

The process of wide being the river by eroding its banks. Happens most in the middle and lower courses of a river where there is lower energy.

Question 37

Describe what solution transportation is.

Answer 37

When dissolvable substances on rocks are dissolved and carried along in the water. E.g; limestone’s dissolved in water that’s slightly acidic.

Question 38

Describe what saltation transportation is.

Answer 38

A process associate with relatively high energy conditions where small stones (e.g; pebbles/ gravel) bounce or leapfrog along the channel bed

Question 39

What is suspension transportation?

Answer 39

When fine material (e.g; silt/ clay) is whipped up by waters turbulence and carries along in the moving water in the rivers load.

Question 40

Describe what traction transportation is.

Answer 40

When very large particles, for example boulders, are pushed along the river bed by the force of the water in the river- associated with very high energy.

Question 41

What is a rivers competence?

Answer 41

The maximum size of a particle a river can carry in its load at a given point.

Question 42

What is river capacity?

Answer 42

The total load a river can transport at a certain point- measured in weight/ mass/ volume.

Question 43

What is the fall velocity curve?

Answer 43

The line on the Hjülstrom curve that shows the velocity at which the particles are deposited and illustrates the rivers competence at different given velocities.

Question 44

Explain what the critical erosion velocity of a river is.

Answer 44

The line on the Hjülstrom curve that shows the minimum velocity needed for a river to pick up and transport material of different sizes within its load.

Question 45

What is a logarithmic scale?

Answer 45

The scale the Hjülstrom curve goes up in. It goes up in tens- e.g; 0.1,1,10,100 etc.