Water

Water, is the basic necessity of human survival. However, because of overwhelming demand, there may be a water shortage. This is known as water constraint.

Why do we have water constraints?

Limited supply
Three-quarters of the Earth is filled with water. However, out of this, 97percent is made up of salt water in seas and oceans. Fresh water frozen in the form of snow and ice makes up another 2percent. Hence, only one percent of the water on earth is made up of fresh water that is readily available for human consumption. This water can be found in lakes and rivers and also from the ground.

Uneven distribution of water globally

Differences in climate also cause water constraints in countries. For example, India has only 10percent of fresh water supply. However, it has a large population. Hence, India is unable to provide everyone with fresh water, hence we can say that India is facing water constraint.

Polluted waters
Even when there is abundant supply of fresh water in a country, not all of it can be drunk. This is due to the pollution found in the water. Waste from industries are dumped into water sources, like lakes and rivers. Such an example is Lake Baikal in Russia.

Population growth

As the number of people on Earth is growing, the little supply if fresh water has to be shared among more people. This will worsen the problem of water constraint in many countries.
Water for agriculture

As the population increases, more food has to be growth to feed the people. Hence, more water will be needed for agriculture. Hence, up to three-quarters of the world's fresh water supply is used for the watering of crops and the rearing of livestock.
Growth of industries

Water is needed for industries. For example, water is used to cool down machines and as a raw material in making products such as paper,food, chemicals and paint.

Changed in lifestyle

As a country becomes more developed and urbanised, people can afford to buy items that provide them with greater convenience and comfort. For example, people would like a pool to be built in their homes. This thus increases the demand for water.

Responses to rising demand for water

Increase the price of water

When prices of water are increased, people who cannot afford the price of water will be encouraged to use less water. The poor will suffer. This method is not effective as this does not curb the demand for water. This also will cause a difference in social status.

Increase catchment areas

A catchment area is an area where rain falls and is collected. An example, is Upper Seletar Reservoir.

Nature reserves are typically used as catchment areas because forests can retain a supply of fresh water. Rainwater is intercepted by the trees ans plants. It is then absorbed into the many soil layers in the ground. This water will be eventually drained into a reservoir for storage.

Increasing catchment areas will increase the supply of water and help lower the cost of water treatment. This is so as rainwater is cleaner than used water and does not contain salt, like seawater. Hence, it is easier and less costly to purify.

Treatment process[, represents to]

Reservoir , pumping station, raw water mixing chamber, settling tank, sand filter, disinfection, clear water tank, pumping station, service reservoir, industries and homes

Water catchment areas are also used for recreational purposes.

However, large areas of land has to be set aside for water catchment areas. This thus, poses a problem for countries facing land constraint. This is so as land cannot be used for urbanisation, like building of homes. Hence, building of homes is the opportunity cost.

Another disadvantage of water catchment areas is that rain is a natural event. Hence, the country has little control over the amount of rain that falls. Hence, during times of drought or little rainfall, land used for water catchment areas will be ineffective. However, government can try cloud seeding in order to get more rain. However, this is expensive as chemicals used are not cheap.

International agreements

Countries can obtain water from neighbouring countries under international agreement. An international agreement is an arrangement between two or more countries regarding the supply and uses of water resources over a period of time.

An advantage of obtaining water from another country is that this is a convenient way of increasing the supply of water.

However, this agreement is not forever, and can expire. Hence, countries doing this cannot have self-sustainacy and may face a risk of water shortage, should the other country stop supplying water.

Recycling water[water reclamation]

Used water is collected from households and factories and channeled into a water recycling or water reclamation plants where impurities are removed. The product is called recycled water or reclaimed water. The treated water from these plants are further treated at industrial water works, to produce industrial water. Industrial water is supplied to factories for the washing and cooling of machinery.

1. Water is passed through a process of microfiltration, where larger particles and bacteria are removed.

2. Reverse osmosis is carried out. This is where pressure is applied to the water, to force it through a special membrane. This process removes very small particles such as bacteria and dissolved salts.

3.The water is disinfected under Ultraviolet radiation.

Desalination

This is the process where salt is removed from sea water. This is commonly used in dry regions in the world and in places where water supply is too contaminated. Saudi Arabia has the world's largest desalimination plant, producing up to 12million gallons of fresh water each day.

There are various methods of disalination. One such method is distillation. In this process, water is boiled and water vapour is collected and condensed into fresh water. This method is expensive as it requires alot of energy to heat up the water. Solar energy can be used to heat up the water too.

Another method of disalination is purifying the water by reverse osmosis. Seawater is pumped at high pressure through a special membrane which separates the dissolved salts from the water.

Advantages and disaddvantages of using technology

An advantage of using technology to obatin water is that technology greatly increases the supply of water.

However, technology is expensive to harness. For example, the Newater plant at Bedok costs $6.82 million to construct.

People may not get used to the taste of treated water. This is so as during the treatment process, minerals in the water are removed, giving it a different taste from water obtained from traditional sources, such as reservoirs. Hence, the government in Singapore pipes the treated water into reservoirs first, before distributing it to schools, homes and factories.

Conserving water

Besides increasing the supply of water, we can also conserve water, to ensure that there is sufficient water to meet the population needs. The supply of water from water catchment areas and other sources is limited and can run out. Water conservation hence, helps to reduce the risk of future water shortage, by encouraging people and industries to use less water before its too late.

water conservation can help reduce the need to develop new facilities or upgrade exsisting facilities to increase water supply. Not only are these facilities expensive to built, they also take up land for other purposes like housing and industries.

Campaigns can be used to educate the public. However, this is not an easy task as this involves getting people to make changes to their lifestyles.

Reflection

Learning about water constraints is very important. This is especially so for Singapore. Singapore does not have neighbours that care deeply for us. We do not have neighbours who want us to thrive. We have a large population but little land. Singapore did not have any of her own water sources when we first started out. It was not until NEwater was discovered. Hence, NEwater has helped paved the first step in achieving self-sustainacy for Singapore. However, there is still many problems with NEwater. One such problem is the high cost of NEwater plants. If the future generation can think of more innovative solutions to combat the high cost of NEwater plants, i believe that Singapore will be able to thrive, in our strategic location.

When Singapore has perfected the NEwater technology, we can sell this technology globally. Only then, will the world not face a water shortage.

-Samantha lye

-samantha lye