Water cycle units 1-3 practice Flashcards
State the main input to a drainage basin
Precipitation
State the three main outputs of a drainage basin
Evaporation
Transpiration
River flow (run-off) into Ocean
State the three main flows in a drainage basin
River flow
Percolation
Vapour Transport
State the two stores in a drainage basin
Groundwater
Soil
What’s the difference between an open and closed system?
Open system: a system in which the quantity of matter will vary over time
Closed system: a system in which the quantity of matter is fixed
Why is a drainage basin an open system?
the quantity of water will fluctuate over time due to variations in the quantity of inputs and outputs.
Why is the global water cycle a closed system?
the quantity of water is fixed as no water leaves the planet and no new water is created
On a global scale, what’s the fixed amount of water present?
1.4 billion km3
What percentage of the global water is stored in oceans?
97%
what percentage of global water is stored in the cryosphere?
2%
what percentage of global water is stored in groundwater?
1%
What’s the link between the cryosphere and ocean store?
As rates of accumulation and rates of ablation increase within the cryosphere, runoff causes the store of water in the oceans to increase
What two factors causes sea level fluctuations on a short timescale of years?
Seasonal changes in snow fall and ice formation
Variations in global temperature from year to year ( volcanic eruptions, El Nino events – this will be covered later in the course)
State the change in size of stores over space and time
Increase in Cryosphere store:
- ice sheet extended across Scandinavia, North Sea and northern Britain. Thickness of ice exceeded 2500m over Scandinavia. Smaller Ice Caps covered Iceland, the Alps and Pyrenees mountains.
- increase in sea ice which extended through large area of the North Atlantic as far south as Ireland.
Reduction in Ocean store:
- Due to quantities of water stored in the cryosphere, sea levels around Europe were over 100m lower than present day
Define a simple river regime
one in which there is a clear seasonal difference between a period of high water levels and a period of low water levels
Define a complex river regime
one in which the pattern of discharge has multiple peaks and more variable flow
State the climate factors influencing river regime characteristics
Annual variation of precipitation quantity: this will determine the amount of water entering the drainage basin
Annual variation of precipitation type: this will determine if the precipitation enters a river
Annual variation in levels of evapotranspiration: this will determine the level of an important output from the drainage basin
Annual variation in temperature: this will determine not only evaporation but also if and when water is in a frozen state
State the human factors influencing river regime characteristics
Dam construction: this will control the level of channel flow downstream of the dam
Land Use Change: Changes in the levels of interception, infiltration, surface run-off, base flow etc. could occur if land use change takes place in a drainage basin. This will determine the amount and rate at which precipitation can become channel flow.
Define lag time
The period between maximum precipitation and peak discharge
Define rising limb
The rising portion of the hydrograph showing increased levels of discharge
Define peak discharge
The point in time where the river reaches its highest level
Define bankful discharge
When the level of discharge is at the channel capacity and any further increase in discharge will result in flooding.
Define the falling limb
The period where discharge is decreasing and the level of the river is falling
Define baseflow
The portion of discharge fed from groundwater flow
State the climatic factors influencing a storm hydrograph
Precipitation type, amount, duration and intensity, temperature, evaporation, transpiration and antecedent conditions
Define antecedent conditions
wet conditions before a storm that cause the ground to become saturated