5.3

Question 1

What do water budgets show?

Answer 1

The annual balance between imputs and ouputs

Can be used on a global and national scale.

In the UK precipitation exceeds evaporation most years, so there is a positive water balance.

Question 2

What is a river regime?

Answer 2

The annual variation in discharge or flow at a particular point.

Question 3

What influences river regime?

Answer 3

• Size of river
• Amount, pattern and intensity of rainfall
• Temperatures
• Geology and outlying soils
• Type of vegetation cover
• Human activities such as dam building

Question 4

What do storm hydrographs show?

Answer 4

They show the variation if discharge is within a short period of time, normally a storm or group of storms less than a few day in length.

Question 5

What are the impacts of Urbanisation?

Answer 5

• Building activity leads to the clearance of vegetation which exposes the soil and increases
Overland flow. Piles of disturbed and dumped soil increases erodibility.
• The soils replaced with impermeable surfaces.
• The high density of buildings means that rain falls on the roots and then swiftly dispatches into drains
• Drains are built which reduce the distance that water must travel before reaching a channel.
• The increase in the velocity occurs because they generate less friction then natural pathways.

• Bridges can restrain the free discharge of floodwater and act as local dams.

Question 6

What are water budgets useful for?

Answer 6

• Calculating amount of water available for human use and the availability of water in soils.

Question 7

Amazon water regime

Answer 7

• High flow Dec-May
• Low flow Jun-Nov
• Moderate variability
• Human interference increasing

Question 8

Alaska water regime

Answer 8

• High flow Apr-Aug (snowmelt)
• Low flow Sep-Mar (ice forming)
• Large variability
• Little human interference

Question 9

Flashy storm hydrograph

Answer 9

• Discharge steap rising and falling limb
  -Short lag time

Question 10

Subdued storm hydrograph

Answer 10

• less rainfall (more slopes)
• shallow rising limb
• longer lag time
• less water overall
• more manageable - less change and fewer flooding events

Question 11

What can affect a storm hydrograph?

Answer 11

• Weather and climate
• Rocks, soil, relief
• Basin characteristics
• Vegetation
• Antecedent conditions
• Human activity