4 - Water and its Management

Describe the distribution of the earths oceans

97% of the earth's water are saline oceans, and 3% is fresh water

Describe the distribution of the earths freshwater ice sheets and glaciers

Of the 3% of freshwater on earth, 69% is icecaps and glaciers

Describe the distribution of the earths ground water

Of the 3% of freshwater on earth, 30% is ground water

Describe the distribution of the earths lakes and rivers

Of the 3% of freshwater on earth, there is 0.3% of fresh surface water - of this, 87% are Lakes, and 2% are rivers

What are some of the stages involved in the water cycle?

Precipitation, surface run off, interception, infiltration, through flow, ground water flow, transpiration, evaporation and condensation

What is precipitation?

Moisture that reaches the surface in the form of rain, sleet, snow, or hail, with rain being the most common type

What is surface runoff?

Precipitation that flows over the ground surface, eventually finding its way into streams and rivers.

What is interception?

Precipitation that doesn't reach the Earth's surface due to being obstructed by trees and plants

What is infiltration?

Precipitation soaks into sub-surface soils and moves into rocks through cracks and pore spaces.

What is through flow?

Downslope movement of water through the soil, roughly parallel to the ground surface.

What is ground water flow?

Slow horizontal movement of water through rock.

What is transpiration?

Evaporation or diffusion of water from plant leaves.

What is condensation?

Water vapour converted back into liquid (water droplets) or solid (particles of ice) due to a decrease in temperature with increasing height by air currents, e.g. clouds.

What are some of the sources of fresh water used by people?

Aquifers, wells, rivers, reservoirs and desalination plants

What are aquifers?

Water stored in porous rocks under the ground - alternating layers of permeable and impermeable rocks trap the water so it accumulates, and mechanical pumps, or human labour are used to raise water to the surface

What is a well?

A hole bored or dug into rock to reach the water stored in them.

What is a river?

A large, natural stream of water flowing in a channel to the sea, a lake, or another river.

What is a reservoir?

An artificial lake used as a source of water supply, usually created behind a dam or by the side of a river (bank-side reservoir).

What is a desalination plant?

Desalination plants remove salt from saline waters to produce fresh water safe for human use - this can be done by distillation where water is boiled and released as vapour, leaving salt behind or reverse osmosis, where salt water is pumped at high pressure through a fine membrane

What are the 3 different ways fresh water can be used?

Domestic, industrial and agricultural

How can fresh water be used for domestic purposes?

For washing and flushing the toilet, washing clothes, gardening, washing cars or even lost in leaks

How can fresh water be used for industrial purposes?

They can be used in factories for cooling, mixing and making products such as dyes and paints, bottling and canning in food and drink industries and power generation

How can fresh water be used for agricultural purposes?

Mainly for irrigation, as plats need water for transporting minerals for photosynthesis and for the prevention of wilting, and for domestic animals

Describe the availability of safe drinking water in water rich regions

These are countries with plentiful water supplies - some are large countries with plenty of land for rain to full on - eg Russia, China and some have the worlds greatest rivers (Amazon, Yangtze etc) - but big areas don't ensure water availability eg Australia and Sudan, due to lots of deserts in them

Describe the availability of safe drinking water in water poor regions

These are countries with scarce fresh water supplies, dominated by desert countries - they are also tiny island states that have only small areas for rain to fall on (except Singapore and Mauritius as they receive high precipitation totals)

Why is there a potential for water conflict?

There could be conflict between countries, states or groups over an access to water resources

Why do urban areas have higher access to safe drinking water than rural areas?

Because cities are more wealthy with factories and offices, and peoples income is higher - its easier to put pressure on politicians to make improvements and there are more wealthy people in cities - water pipes are easier and cheaper to build when a lot of people live closer together

What are some things to consider for the choice of site of a dam?

There should be high precipitation of enough water, low temp preventing evaporation, it should be built on strong impermeable rock so water doesn't drain, built high so theres potential for hydroelectric power, narrow and steep valley, rivers and lakes for water, away from developed areas reduce risk of pollution and easy accessibility

What are the positive environmental impacts of multipurpose dam projects?

They create habitats for wetland species, and are a renewable energy source reducing fossil fuel consumption

What are the negative environmental impacts of multipurpose dam projects?

They disrupt the life cycles of fish and other aquatic organisms and reduce soil enrichment downstream of the dam

What are the positive economic impacts of multipurpose dam projects?

They help generate electricity in hydro electric power plants and create recreational land for tourism and leisure

What are the negative economic impacts of multipurpose dam projects?

The dam may become reductant due to sediment build ip and its very expensive build and requires maintenance

What are the negative social impacts of multipurpose dam projects?

They relocate people and flood land, and farmers jobs are reduced if natural fisheries are affected - the wager supply for people downstream of the dam is also affected

How are dams sustainable?

They are an alternative for burning of fossil fuels as no greenhouse gases are produced.

How are dams unsustainable?

Reservoirs can become silted due to material carried into it by rivers, the dam structure, which is under a lot of pressure can deteriorate and eventually fall, and it can have negative effects on environment and fish population

What are the sources of water pollution?

Domestic waste, including sewage from urban and rural settlements, industrial processes and agricultural practices

How is domestic waste a source of water pollution?

Sewage is usually disposed in water bodies, and contain many pathogenic micro-organisms, increasing the content of nitrates and phosphates in rivers - detergents, metals and other manufactured products contain traces of toxic chemicals too, which r disposed in water

How are industrial processes a source of water pollution?

The use of chemicals, processing of metal ores and leaching of metals from waste heaps and dumps cause the presence of metals in rivers

How are agricultural practices a source of water pollution?

Surpluses of phosphorus and nitrogen not absorbed by the plants are washed form the land or percolate into ground water - on farms, manure, synthetic fertilisers and chemical pesticides are main sources

What are the impacts of fresh water pollution on people?

Global inequalities in sewage and water treatment, and increased risk of infectious bacterial diseases, such as typhoid and cholera

How are global inequalities in sewage and water treatment caused by freshwater pollution?

Developing countries have difficulty treating water and sewage compared to developed countries as people aren't educated and can't put pressure on the government.

How is an increased risk of infectious bacterial diseases, such as typhoid and cholera, caused by freshwater pollution?

Water-borne diseases are caused by drinking contaminated water.

What are the impacts of fresh water pollution on the environment?

Accumulation of toxic substances from industrial processes in lakes and rivers, bioaccumulation of toxic substances in food chains, the effect of acid rain on organisms in rivers and lakes and nutrient enrichment leading to eutrophication

How is accumulation of toxic substances from industrial processes in lakes and rivers caused by freshwater pollution?

Toxic substances from industrial processes accumulate in lakes and rivers - this reduces oxygen in lakes and rivers, causing reduction of photosynthesis and death of fish and insect larvae

How is bioaccumulation of toxic substances in food chains caused by freshwater pollution?

As animals consume these toxic substances, they get passed down the food chain, increasing concentration of a toxic substance in the tissues of organisms at successively higher levels in a food chain, causing illness

What is acid rain ?

Burning fossil fuels produce sulphur dioxide and nitrogen oxides, that react with water in the atmosphere - SO2 dissolves in water to form sulfuric acid, and NOx dissolves to form nitric acid that fall in the form of rain

What are the effects of acid rain on organisms in rivers and lakes?

Low pH so less aquatic life, fish eggs are reduced and young fish malformed, leaching of heavy metals such as aluminium from soil to water, aluminium clogging fish gills, causing suffocation and mineral essential for life (calcium and potassium) are washed out lake, reducing algae growth and leaving less food for fish + animals

How is nutrient enrichment, leading to eutrophication, caused by freshwater pollution?

An increase in nutrients such as nitrates in water body causes algal bloom - dead algae increases organic matter that is food for bacteria as they decompose dead algae - bacteria use oxygen, reducing oxygen in water so organisms die

What are some strategies for improving water quality?

Improved sanitation, treatment of sewage and pollution control and legislation

How is improving sanitation a strategy for improving water quality?

You can separate human waste and waste water from contact with humans via connection to sewage by toilets etc - flush toilets use a holding tank for flushing water and a water seal to prevent smells

How is treatment of sewage a strategy for improving water quality?

Waste is taken to sewage treatment plants to take out contaminants like chemicals and germs - this also stops diseases in dirt water - large objects are removed and it is made safe for human consumption by being treated, filtered and disinfected - now it can be used for swimming, fishing etc

How is pollution control and legislation a strategy for improving water quality?

This pressures polluters to reduce pollutants - industries have to monitor pollution they cause and keep it at a set level, with the government fining or prosecuting them if they exceed this - companies need government agreement on strategic plans to reduce pollution levels, and incentives, such as grants or tax reliefs, are used to encourage companies to reduce pollution

Describe the life cycle of a malaria parasite

Mosquito injects plasmodium (parasite) into human which enters liver cells - it multiplies by cell division, but the liver cells burst, releasing plasmodium into human blood- this is transmitted to a mosquito when it bites and ingest human blood - plasmodium multiplies inside mosquito and is transmitted to humans when a mosquito injects it via bite

What are some strategies to control malaria?

Spraying antimalarial drugs on water to kill larvae, controlling the vector (mosquitoes) by using vaccinations, educate people on malaria using campaigns and programmes, sleeping under mosquito nets and you can eradicate them by using kerosene to choke larvae and eliminating breeding grounds

What are some strategies to control cholera?

Keeping drinking water is safe by ensuring sewage + drinking water are kept separate, sewage is removed directly into treatment works, water is treated before its delivered to homes, contaminated water shouldn't be used to wash food and hands should be washed after any contact with faecal material - water can also be boiled and use chlorination