River Discharge

Question 1

What is river discharge?

Answer 1

The volume of water flowing in a river per second.

Question 2

What is the volume of water measured in?

Answer 2

Cumecs - cubic metres per second.

Question 3

What do hydrographs show?

Answer 3

How the discharge at a certain point in a river changes over time.

Question 4

What shows the changes in discharge around the time of a storm?

Answer 4

Storm hydrographs.

Question 5

What is the peak discharge?

Answer 5

Highest discharge in the period of time you’re looking at.

Question 6

What is lag time?

Answer 6

Delay between peak rainfall and peak discharge.

Question 7

What is rising limb?

Answer 7

Increase in river discharge as rainwater flows into river.

Question 8

What is falling limb?

Answer 8

Decrease in river discharge as river returns to normal level.

Question 9

Why does lag time happen?

Answer 9

Most rainwater doesn’t land directly in the river channel.

Delay as rainwater gets to channel.

Question 10

How does the water get into the river channel?

Answer 10

Flowing quickly over land.

Soaking into the ground and flowing slowly underground.

Question 11

What is the name when water quickly travels over land?

Answer 11

Surface runoff.

Runoff.

Question 12

What is the name when water soaks into the ground?

Answer 12

Infiltration.

Question 13

River discharge is affected by…

Answer 13

Different factors.

Question 14

More water that flows as surface runoff…

Answer 14

The shorter the lag time.

Question 15

Shorter the lag time means…

Answer 15

Discharge will increase as more water gets to the channel in shorter space of time.

Question 16

Name the 6 different factors river discharge is affected by?

Answer 16

Amount/type of rainfall.
Temp.
Previous weather conditions.
Rock type.
Land use.
Relief.

Question 17

Lots of rain and short, heavy periods of rainfall means…

Answer 17

More surface runoff.

Question 18

Lag time decreased so…

Answer 18

Discharge increased.

Question 19

What weather conditions result in hard ground?

Answer 19

Hot, dry.

Cold, freezing.

Question 20

Hot, dry.
and
Cold, freezing weather increases what?

Answer 20

Increases surface runoff.

Question 21

Lag time is decreased so….

Answer 21

Discharge increases.

Question 22

After lots of rain soil can become what?

Answer 22

Saturated.

Question 23

What does saturated mean?

Answer 23

Unable to absorb any more water.

Question 24

If the soil is saturated what will happen?

Answer 24

Rainwater won’t be able to infiltrate into soil.

Question 25

If less rain is able to infiltrate what will happen?

Answer 25

Surface runoff increases.

Question 26

Water can infiltrate through…

Answer 26

Pore spaces in permeable rock.

Flow along cracks in previous rocks.

Question 27

If rock can infiltrate through pore spaces and along cracks in rocks it means…

Answer 27

Isn’t much surface runoff.

Question 28

Water can’t infiltrate through…

Answer 28

Impermeable rocks.

Question 29

If rocks can’t infiltrate through impermeable rocks then what does it mean?

Answer 29

Lot of surface runoff.

Question 30

What do urban areas have?

Answer 30

Drainage systems.

Question 31

What are urban areas covered in?

Answer 31

Impermeable material.

Concrete.

Question 32

Define relief

Answer 32

How the height of the land changes.

Question 33

What occurs on steep slopes?

Answer 33

Lots of surface runoff.

Question 34

When there’s a lot of surface runoff there is decrease in…

Answer 34

Lag time.