1.2 River Discharge and the Storm Hydrograph

Question 0

What is discharge measured in?

Answer 0

Cumecs (cubic metres per second)

Question 1

What is river discharge?

Answer 1

☔️ The volume of water passing at one point.

Question 2

What five factors affect the discharge of a river?

Answer 2

Distance downstream 
Climatic characteristics
Land use
Water abstraction (removal)
Channel modifications

Question 3

Affect of distance downstream on discharge:

Answer 3

River discharge increases with distance downstream.

From the addition of water from smaller tributaries.

Question 4

Affect of climate on river discharge:

Answer 4

Precipitation, eg snow melting=surge in discharge

Evaporation rates and vegetation growth

Question 5

Affect of land use on discharge:

Answer 5

Afforestation, reduces discharge

Urbanisation often increases discharge. Forces water to transfer rapidly over impermeable surfaces (Tarmac, concrete)

Question 6

Affect of water water abstraction on river discharge:

Answer 6

Domestic use or for crops especially in the summer reduces discharge

Question 7

Affect of channel modifications on river discharge:

Answer 7

Increase discharge: reducing flood risk, widening and enlargement

Decrease discharge: river restoration and creation of flood storage

Question 8

What are some characteristics of a flashy hydrograph?

Answer 8

Small basin= rapid water transfer
High drainage density
Impermeable rocks=encouraging overland flow
Urbanisation
Steep slopes
Saturated soils
High rain intensity exceeding the infiltration capacity

Question 9

Characteristics of a low, flat hydrograph with a low peak

Answer 9

Large basin 
Low density 
Permeable rocks
Forests 
Gentle slope
Dry soil
Light rain