1. Processes operating within cycle from global to local scale?

Question 1

Why is it a closed system?

Answer 1

➢ Hydrological cycle is a closed system because water is neither created nor destroyed on a large scale.

➢ Water exists as solid, liquid and gas phases that are interchangeable at temperatures found on earth.

Question 2

What is it driven by?

Answer 2

➢ Solar Energy: Heat energy by Sun

➢ GPE: pulling materials down to earth

Question 3

Outputs in water cycle [3]

Answer 3

1. River Discharge
2. Evaporation
3. Transpiration

Question 4

Inputs in water cycle [1]

Answer 4

Precipitation

Question 5

Transfers in water cycle [7]

Answer 5

1. Stem Flow
2. Surface Runoff
3. Infiltration
4. Through flow
5. Channel Flow
6. Percolation
7. Base Flow

Question 6

Stores in water cycle [6]

Answer 6

1. Interception
2. Surface Storage
3. Vegetation Storage
4. Soil Moisture Storage
5. Channel Storage
6. Ground water

Question 7

Transpiration?

Answer 7

Process where plants absorb water through roots that give off water vapour through the stomata

Question 8

Evapotranspiration?

Answer 8

Process by which water is transferred from the land to the atmosphere by evaporation from the soil and other surfaces and by transpiration from the plants

Question 9

Soil moisture Storage?

Answer 9

Amount of water stored in soil. It can be affected by precipitation, temperature, soil characteristics and more

Question 10

Through flow?

Answer 10

Horizontal flow of water within the soil layer. Normally takes place when the soil is saturated.

Question 11

Channel flow?

Answer 11

Water flowing through a river

Question 12

Top 3 storage?

Answer 12

1. Ocean
2. Cryosphere
3. Groundwater

Question 13

Define Water Budget

Answer 13

➢ Accounting of the rates of water movement

➢ Change in water storage

➢ Parts of the atmosphere, land surface, and subsurface.

Question 14

Fossil water Storage?

Answer 14

➢ Non renewable

➢ Water stored within the ground over thousands of years

➢ Non-renewable, it takes 1000yrs to make

Question 15

Types of Rainfall [3]

Answer 15

1. Convectional Rainfall
2. Frontal Rainfall
3. Orographic Rainfall

Question 16

Convectional Rainfall?

Answer 16

Sun heats the water source to the point that water turns into vapour and rises.

At condensation level, the vapour is usually cooled enough to turn back into the water and fall in the form of rain

Question 17

Frontal Rainfall?

Answer 17

Two air masses meet, one a warm air mass and one a cold air mass.

Question 18

Orographic Rainfall?

Answer 18

Rain that is produced from the lifting of moist air over a mountain. Orographic precipitation, rain, snow, or other precipitation produced when moist air is lifted as it moves over a mountain range.

Question 19

How physical factors affect the relative importance of inputs, flows and outputs?

Answer 19

➢Climate – influences amount of rainfall and vegetation growth.

➢ Soil Composition – influences rate of infiltration and through flow.

➢ Geology – affects percolation and groundwater flow

➢ Relief – steeper gradients of land will encourage faster rates of surface runoff

➢ Vegetation – affects interception, overland flow

➢ Size – larger basins collect more precipitation generally

Question 20

How human factors affect the relative importance of inputs, flows and outputs?

Answer 20

➢ Cloud seeding – substances dispersed into the air to provide something for condensation to occur on in

➢ Deforestation – Less vegetation means less interception, less infiltration, more overland flow leading to more flooding, cycle speeds up

➢ Afforestation – More vegetation means interception, less overland flow, more evapotranspiration

➢ Dam construction – Dams reduce downstream river flow and discharge, increase surface stores so more evaporation

➢ Change in land use – Infiltration is 5 times faster under forests compared to grasslands. Converting land to farmland means less interception, increased soil compaction and more surface runoff

➢ Ground water abstraction – When water is taken out faster that the water is recharged, groundwater flow decreases and the water table drops Example: In China, groundwater irrigates 40% of farmland whilst 70% of drinking water comes from groundwater

➢ Irrigation – Drop in water tables due to high water usage. Example: Aral Sea in Kazakhstan shrank in 1960s due to farmers using the water to grow cotton

➢ Urbanisation – Impermeable surfaces reduce infiltration, increase surface runoff, river discharge increase.

Question 21

River Regime?

Answer 21

describe one of two characteristics: The variability in its discharge throughout the course of a year in response to precipitation, temperature, evapotranspiration and drainage basin characteristics

Question 22

Variations w/Regime: Factors that influence?

Answer 22

▪ Channel capacity of the river
▪ Area and relief of the drainage basin
▪ Volume, pattern and intensity of precipitation
▪ Climate
▪ Geology of the soil (affecting the input of groundwater)
▪ Anthropogenic (human) activities, such as building dams or terracing the land.

Question 23

Regimes from contrasting river basins? [Case Study]

Answer 23

1. Yukon, Alaska (USA)
2. Amazon Brazil
3. Murray- Darling River

Question 24

River Regime [CS] : Yukon, Alaska (USA)

Answer 24

High Flow:
Spring and Summer (snowmelt)

Low/ No Flow:
Winter (frozen precipitation)

Seasonal Variability:
Very Large

Human Influences:
Relatively Few- Most of its landscape is wilderness. Some HEP use for mining industries.

Question 25

River Regime [CS] : Amazon, Brazil

Answer 25

High Flow: 
Wetter Season (December to May)

Low/ No Flow: 
Drier Season (June to November)

Seasonal Variability:
Moderate Variability- fed by Andean rivers outside of rainforest region.

Human Influences:
Increasing (although a low percentage of its flow at present); large dams used by Brazil’s major cities for irrigation and HEP.

Question 26

Purpose of Hydro graphs?

Answer 26

➢Storm hydrographs represent the variation in discharge within a short period of time (days, rather than years)

➢Before a storm begins, the main supply of water to the river is through groundwater or base flow.

➢However, as a storm develops, infiltration and surface runoff will increase which causes a greater throughflow