Water Cycle EQ1

Question 1

Importance To Life On Earth

Answer 1

Operates as a closed system (1) driven by solar energy through heat and gravitational potential energy which causes rivers to flow downhill and precipitation to fall to the ground.

Question 2

Importance and Size of Stores and Fluxes

Answer 2

Stores are resevoirs where water is held.
The stores are he atmosphere, the cyrosphere (2), surface runoff and the oceans. The cryosphere holds 69% of freshwater and groundwater holds 30%. Flows are the movement of water from one store to another and fluxes are the rate of flow.
Biggest fluxes over the ocean.

Question 3

Global water budget

Answer 3

Global water budget shows how water is distributed over various stores. Despite the Earth’s abundance of water, only 2.5% is freshwater, and just 1% of that is easily accessible surface water, the main source for human use. Most freshwater is locked in glaciers and ice sheets (69%) and groundwater (30%).

Each water store has a residence time, ranging from 10 days in the atmosphere to thousands of years in oceans and ice caps. Some water stores, like fossil water (3) and the cryosphere, are considered non-renewable, though this is debated for glaciers.

Question 4

The Hydrological Cycle Inputs

Answer 4

The main input is precipitation, which can vary in many different ways.
Form: rain, snow or hail.
Amount: this will affect the amount of water in the drainage basin and the fluxes within it.
Intensity: the greater the intensity, the greater the likelihood of flooding.
Seasonality: this is likely to result in the drainage basin system operating at different flow levels at different times of the year.
Distribution: this is significant in very large drainage basins, such as the Nile and the Ganges, where tributaries start in different climate zones.

Question 5

Hydrological Cycle flows

Answer 5

Interception: the retention of water by plants and soils which leaves though evapotranspiration
Infiltration: the process by which water soaks into or is absorbed by the soil
Percolation: The absorption of water within rocks
Throughflow: the lateral transfer of water downslope through soil
Surface Runoff: Movement of water on land outside of a river or channel
River/Channel flow: The flow of water in a river or channel

Question 6

Hydrological Cycle outputs

Answer 6

Evaporation, transpiration, discharge

Question 7

What is a drainage basin

Answer 7

A drainage basin, also known as a river catchment, is the area of land drained by a river and its tributaries. Its boundary is marked by the watershed.

Question 8

Factors influencing drainage basins

Answer 8

Climate: Impacts inputs and outputs and also impacts vegetation and water availability
Soils: Determines Infiltration, throughflow and surface runoff and affects vegetation growth and water retention
Geology: Affects subprocesses like percolation and groundwater flow and impacts aquifers and soil formation
Relief: affects precipitation levels and slope gradients e.g. steeper slopes lead to increased runoff
Vegetation: Impacts infiltaration, interception and transpiration and it reduces surface runoff and aids water retention

Question 9

Human Factors impacting the drainage basin

Answer 9

River Management: Reservoirs reduce river flow.
Water abstraction (domestic, industrial, irrigation) lowers river levels and water tables.

Deforestation: Reduces evapotranspiration, increasing surface runoff and infiltration.

Land Use Changes
Agriculture:
Livestock compacts soil, increasing runoff.
Ploughing loosens soil, increasing infiltration.
Urbanisation:
Surfaces like tarmac and concrete speed up runoff and reduce infiltration, raising flood risks.