Geography Edexcel B Water World

Evaporation- water warmed by the sunlight, returned to the atmosphere in vapour form

Condensation- water vapour cools, condenses and tiny water droplets form, often as a cloud

Precipitation- water droplets collide and grow; getting bigger until under gravity they fall to the earth as snow or rain

Run-off- when rain-fall runs quickly over the surface of the land

Throughflow- when the water has soaked through to the soil (infiltration) and is slowly transferred through the soil until it reaches a river

Groundwater flow- once it has entered the soil, some reaches the rock below and flows through tiny air holes, called pores and along cracks called joints. 

• water evaporates from oceans
• water evaporates from the land
• the evaporated water falls back to the ground as snow and or rain
• surface run-off also occurs: rivers, lakes and sometimes flash floods
• glaciers and vegetation store the water 
• water is also returned to the oceans as groundwater flow or through flow
• the water can also be stored as ground water (such as aquifers

lithosphere: the rigid upper part of the earth, consisting of the crust and the upper mantle

biosphere: surface of the earth or another planet occupied by living organisms

transpiration: when water evaporates from the leaf

How the lithosphere helps regulate the Hydrological Cycle?

Soils and rock store water. Porous rocks store water for a longer amount of time such as aquifers. 

How the biosphere helps regulate the Hydrological Cycle?

Trees store water and help to stop river flooding as they delay the amount of time the water takes to reach the river. Also return the water back to the atmosphere during transpiration or when it drips to the ground. 

What impacts may climate change have?

• atmosphere has greater capacity to hold more moisture
• increased precipitation on Northern latitudes
• increased rate of evaporation 
• more floods and greater precipitation means more surface run-off, meaning there is less water to supply rivers during dry seasons
• arid areas may experience more droughts
• wetter areas may experience more precipitation due to the increase in evaporation
• unpredictable rainfall 

The Impacts on humans:

More competition for water, some areas will be at risk of flooding and some arid areas will suffer from water scarcity. Also, change in agriculture, such as plants grown and crop yeild. 

The Impacts on the eco-system:

Salt water will come even further inland, damaging freshwater eco-systems, damage to eco-systems in arid areas as there's less water to supply rivers in dry seasons. 

The Sahel

The impacts on humans:

• increased droughts in the dry season
• desertification made worse, which means there will be increased crop failure, soil erosion, famine and hunger
• people may begin to rely on food from other countries
• increased number of deaths in the young and elderly

Sewage disposal: cholera bacteria spread quickly in river water, when contaminated with human sewage. If toilet waste goes untreated then the cycle of cholera infection will continue to spread. 

Industrial Pollution: when things are leaked into the local rivers of lakes from factories, i.e. calcium sulfate, makes conditions poisonous for wildlife. Can place heavy fines on polluters.

Plastic bags: very thin plastic bags are banned in countries such as Bangledesh and China as they can block water ways and sewage systems, this can ame flooding worse, especially in areas thate xperience monsoon seasons. Can be trapped by vegetation along the river banks, which provides an area of still warm water where maleria bearing mosquitos where breed. 

Intensive Agriculture: fertilisers feed the growth of algea when it is washed into lakes and rivers by surface run-off. When the algea die, the decomposing process deoxygenises the water which causes the death of fish and other acqueous organisms in the lake and or river. 

Transfers of the hydrological cycle can be sped up or slowed down, and natural stores may shrink due to overuse, such as the Aral Sea. 

Changing Transfers- deforastation;

• without trees to intercept surface run-off, run-off is more likely to occur. 
• the increased surface run-off can cause flooding of rivers and lakes
• this is beacuse the trees slowly transfer water through transpiration and the dropping of water from the canopy 

Changing Transfers- urbanisation;

• soil covered by tarmac and concrete
• as a result water travels much more quickly to the nearest river or lake via surface run-off
• drainpipes also speed up urban water flows

Changing stores- acquifers;

• water stores are naturally recharged when it rains
• if water is taken from them too fast they will dry out before they have the chance to recharge 
• many major cities are built above groundwater supplies
• if the water is drained then the wait from the cities buildings will press down on the empty pores in the rock which damages the water storage capacity permanently

The Colorado River (developed world)

Costs:

• natural regime of the river completely altered
• silts and sands trapped behind the dams, rates of transportation and sediments have fallen nearly to zero.
• sandbacks further along the river have been starved of sediment, leading to decline in the number of animal species such as Kanab ambersnail and the Southwestern willow flycatcher
• sandbanks cannot be used for fishing or rafting anymore

Benefits:

• regular all year water supplied to large cities such as Las Vegas
• can be used for recreational use such as boating
• less flood risk as flood peaks are smoothed out

The Three Gorges Dam (developing world)

Costs:

• forced relocation of 1.4 million people
• on going relocation of 100,000 people who have been left vulnerable to landslides and bank collapse
• algal blooms recorded along the length of the reservoir
• increased desposition and sedimentation upstream from the dam]

Benefits:

• help China meet a need of growin domestic and industrial water needs
• decreases the risk of flooding at certain times in the year

Afridev Handpump in Africa

• Tanzania is a despretely poor country in East AFrica
• 30% of urban dwellers have no access to clean water
• water supplies are often contaminated by sewage
• WaterAid helped the community of Chessa villiage construct a new 24m deep well
• it is not very sophisticated so that the local people can take it apart and fix it when it needs to be fixed
• provides people in the villiage with skills as the handpump needs to be taken apart each year to make sure all the parts are working, and may need to be fixed when it breaks down