Summary of Water Supply

Water Supply

Water is a vital resource to sustain life on Earth. It is needed for drinking, cooking, cleaning and many other uses. The amount of water consumed by humans is increasing, but the amount of fresh water available is limited. The problem of water shortage is referred to as water constraint.

More than one-third of the world's population live in countries that are facing the water constraints. Hence, people must find ways to increase their supply of fresh water.

Reasons for Water Constraint

Limited supply of fresh water

Water covers about three-quarters of the Earth's surface. Saltwater makes up 97% of this amount. Fresh water makes up only 3%. Out of 3%, only 1% of the Earth's fresh water is readily available for human consumption. Fresh water can be found deep underground and is known as groundwater. It also be found in rivers, streams and is known as surface water.

Uneven distribution of fresh water

-> Some countries suffer from a lack of fresh water.

-> Some countries have larger populations and require more fresh water than others.

-> Due to the differences in climate, (between a country with an abundance of fresh water and a country with a lack of fresh water) cause an insufficient supply of water for agriculture, leading to a shortage of food for the people.

Water Pollution

-> Due to human activities.

-> Waste from households and factories are dumped into rivers and pollutes the water.

Rising demand for water

-> further contributes to the problem of water constraint

Population growth

-> The world's population had tripled over the past 8- years, thus the demand for fresh water has increased as well.

-> The amount of fresh water available remains the same, so this water has to be shared among more people.

Growth of agriculture

-> With the increasing population, more food is needed to feed the people.

-> Up to three-quarters of the world's supply of fresh water is used to water crops and rear livestock.

-> Large scale irrigation is used to channel water to farming areas that receive little rainfall.

Growth of industries

-> Water plays an important role in the daily operation of the industries

-> Water is used for cleaning and cooling machines and as a raw material in making products such as food, chemicals and paper.

Changes in lifestyle

-> As countries become more developed, people adopt modern lifestyles and can afford to buy items which provide them with more convenience and comfort.

-> Most homes in developed countries have electrical appliances like washing machines and air-conditioner which will lead to the increase in the demand for water.

Responses to Rising Demand for Water

-> If the problem of water constraint is left unsolved, it can lead to more problems such as food shortages.

-> Hence, people can respond to the increasing demand for water in three ways.

Increasing the price of water

-> discourages people from using too much water as they would have to pay more for the water.

-> reduces the cost in producing and distributing water

-> not the best way to respond to the rising demand for water.

-> when water prices increase, only the rich may be able to afford it. The poor will suffer as they cannot afford it.

Increasing the supply of water

-> Three ways in which the supply of fresh water can be increased.

Increase in catchment areas (an area where rain falls and is collected)

-> Increase in amount of water collected.

-> E.g. Singapore's Central Catchment Area, which consists of four major reservoirs surrounded by forests, Upper Seletar Reservoir, Upper Peirce Reservoir, Lower Peirce Reservoir and MacRitchie Reservoir.

-> Forests can retain a supply of fresh water. Trees intercept rainwater and is absorbed by the soil on the ground. This water is eventually drained into a reservoir for storage.

-> Helps to keep the cost of water treatment down. Rainwater is cleaner that seawater and thus, is easier to purify.

-> Forest are conserved and people will be able to enjoy a wider a range of the nature.

-> Less land available for development

-> Rainfall is a natural event and there is no control over the amount of rain that falls.

International Agreements

-> The arrangement of 2 countries regarding the supply and use of water resources over a period of time.

-> Countries discuss and negotiate the terms on the buying or sharing of water resources. (E.g. Bangladesh and India water treaty)

-> Treaty is only valid for a period of time, therefore it is not a long term solution.

-> Countries cannot be certain that they will have enough water to meet their needs.

Use of technology

-> Cloud-seeding, where chemicals are dispersed into the air to allow water droplets to form more easily. (It's effectiveness has yet to be determined)

-> Recycling water, where used water is collected and sent to reclamation plants for the impurities to be removed. The end product is referred to as recycled water. This water can then be further treated to be used in industries or for drinking. (E.g. NEWater)

- Process

1. Microfiltration, where large particles of bacteria are removed.

2. Reverse osmosis. Pressure is applied to the water to force it through a special membrane. Smaller particles of bacteria and dissolved salts are removed from this step.

3. UV disinfection. The water is disinfected with ultraviolet radiation.

-> Desalination is the removal of salt from salt water. It is used to convert seawater to drinking water in many dry regions of the world and areas where water supply is contaminated. (E.g. Saudi Arabia)

Methods:

- Distillation (expensive as it requires a lot of energy to heat the water)

1. Water is boiled

2. Water vapour is collected and condensed into fresh water

- Reverse Osmosis

1. Seawater is pumped at high pressure through a special membrane to separate the dissolved salts from the water.

-> Use of technology is costly (E.g. NEWater plant costs S$6.82 million to construct)

-> Requires large amounts of energy.

-> People may not get used to the idea of drinking treated water as it has a different taste as compared to water obtained from traditional sources (reservoirs). [In Singapore, NEWater is piped into reservoirs before it is re-channelled to homes and other places.]

Conserving water

-> Refers to the careful use of water resources to ensure that the wastage is kept to a minimum.

-> Reduces the risk of future water shortage by encouraging people and industries to use less water.

-> Delays the need for the development of new facilities or upgrading of existing facilities to increase water supply. (Facilities are expensive to build and take up land)

-> Helps households and industries to save on water bills.

-> Requires cooperation from everyone.

-> Water conservation can be encouraged by educating the public through campaigns.

Water Supply In Singapore

-> do not provide an adequate supply of water to meet our demands

Growing demand for water

-> The growth of Singapore's population and industries has increased the demand for water.

Water as strategic resource

-> Without water, many households and industries cannot be able to function normally.

-> Water shortage increases our vulnerability.

Methods to increase water supply

1. Water from local catchment areas

-> More reservoirs are built

- >Stormwater collection ponds have been constructed in some housing estates.

2. Imported water

-> Water is bought from neighbouring countries like Malaysia.

-> Not the best solution as it is not long term. Countries can choose to stop supplying us with water when the agreements expire.

3. NEWater

-> the use of advanced technology to obtain fresh water.

-> supplied mainly to wafer fabrication plants, industrial estates and commercial buildings.

-> mixed with reservoir water before it is sent for treatment at water works. The treated water is then sent to households for consumption.

4. Desalinated water

-> cost is high

-> uses the reverse osmosis method

Policies and campaigns to conserve water supply

-> Impose water conservation tax on the amount of water used.

-> 'Save Water' campaigns have been carried out to educate the people on conserving water.

-> 'Water Efficient Homes' also encourage people to conserve water. Under this programme, more households in Singapore have installed water saving devices to help them conserve water.

There may not enough water for usage as the population and industries continue to grow. Thus, everyone must play their part to keep water catchment areas clean and conserve water, so that there will enough water for the future.

~Kimberley Lim~