Why Humans Need Water

Why Humans Need Water

Introduction

Water is a vital resource for human survival and sustains life on Earth. Its use in domestic, industrial and agricultural sectors plays a crucial role in shaping the world we live in today.

1. Domestic

Water in our homes is used for drinking, cooking, washing, flushing toilets and doing laundry: this is called domestic usage. However, only a small portion of the water we use at home is for drinking and cooking: about 3%. In more economically developed countries, about half of the water is used for washing and flushing toilets, and another 20% for laundry. In poorer countries, people use less water for washing, flushing, and laundry, but this varies. Sometimes people also use water to water plants, and leaks waste a lot of water. It's important for the water we use at home to be clean and safe.

Source: https://www.greenpeace.org/africa/en/blogs/51757/water-crisis-in-south-africa/

Community members wait to collect water at a community tap for their household use. Many people are forced to buy bottled water for drinking purposes because there are concerns about the quality of the tap water.

2. Industrial

Water is used in many different industries for different things. One of the main uses is to cool things down in the making of electricity. Water is also very good at dissolving many different things, which is why it is called the 'universal solvent'.

Source: https://www.miningreview.com/southern-africa/south-african-industry-works-towards-ensuring-water-sustainability/

Water is often used in the mining industry.

3. Agricultural

Water is extremely important in farming because it's used to water crops. This is called 'irrigation' and in some countries, it's the biggest way that water is used. Plants need water to grow and make food, so it's critical that they get enough. Animals on farms also need water to drink. Without water the agricultural sector would be non-existent. Water Sources and Usage

Introduction

Fresh water is essential for human survival, and it can be found in various forms. Surface water, such as lakes, rivers and swamps, is often visible on the Earth's surface and is a major source of fresh water for human use. However, there is a lot more water stored underground, known as groundwater. This water is held in spaces between porous rocks, such as limestone or sandstone, and is stored in a layer called an aquifer.

In areas where there is not enough fresh water available from surface water or groundwater sources, people may turn to other solutions, such as desalination plants that convert saltwater from the sea into potable, or drinkable, water. Desalination plants remove the salt from the seawater, making it safe for human consumption. While desalination can provide a reliable source of fresh water, it can be costly and energy-intensive.

1. Water From Rivers

The methods of obtaining water for human use vary greatly, from simple methods such as digging a well or using a bucket to access a water source, to large-scale projects such as the construction of dams and reservoirs. In some areas, people still rely on traditional methods to obtain water, while in other areas, modern infrastructure has been developed to provide clean, safe water. Reservoirs are large storage areas where water is stored, and they can be created by building dams across rivers or by excavating land beside rivers. Service reservoirs store treated water that is safe for human consumption, and these can be above-ground water towers or underground cisterns.

Source: https://www.pexels.com/search/rivers/

Fun fact: The longest river in the world, the Nile River, is actually getting shorter each year due to erosion and rising temperatures.

2. Water From the Ground

Underground rocks like sandstone and limestone can hold water, and these underground water storage areas are called aquifers. Aquifers hold a lot of the world's fresh water: approximately 30% of it. Aquifers play a crucial role in meeting a substantial part of human water demand.

The primary method of accessing water from aquifers is by digging or drilling wells into the rocks. If the water is not pressurised, it must be lifted manually with buckets or hand pumps, which is common in less developed countries. However, in more developed countries, motorised pumps are typically used to extract the water. If the water is stored under pressure, the aquifer is referred to as an artesian aquifer.

If a well is drilled into an artesian aquifer, which is an aquifer under pressure, the water will flow naturally to the surface without requiring a pump.

3. Water From the Sea

To make salt water drinkable for humans, the salt needs to be removed through a process called desalination. The majority of the world's water, over 97%, is salty ocean water which cannot be consumed as it is harmful to health. There are two methods of making salt water safe for drinking.

The first method of desalination is called distillation. It involves boiling the saltwater until it turns into vapour, leaving the salt behind. The vapour is then collected and cooled, condensing it back into liquid water which can be used. This process is not very efficient: typically only 10-15% efficient. Additionally, the process generates a large amount of waste in the form of saltwater (brine), which can be harmful to the environment if not disposed of properly. The distillation process requires a significant amount of energy to heat the water and create the vapour, which can contribute to pollution. However, transporting fresh water from remote sources also requires energy. Desalination plants that use distillation are primarily found in countries with ample energy resources, such as those in the Middle East. The cost of desalination by distillation may be similar to other methods of obtaining fresh water, depending on the availability of local alternative sources.

Desalination by reverse osmosis

Source: IGCSE Environmental Management textbook

To remove salt from saltwater, the second desalination process is reverse osmosis. In this process, salt water is pushed through thin membranes at high pressure. Reverse osmosis is about 30-50% efficient in removing salt from saltwater. As with distillation, the byproduct of reverse osmosis is brine, which must be disposed of. The energy required for reverse osmosis is less than for distillation. Therefore, most new desalination plants use reverse osmosis techniques.

1. Availability of Safe Drinking Water Around the World

Rainfall is a critical determinant of a country's water wealth. For instance, Brazil and Russia rank among the nations with the highest water wealth due to abundant rainfall. At the same time, the United Arab Emirates and Kuwait are considered among the countries with the lowest water wealth.

However, abundant water resources only guarantee sufficient access to safe water for some individuals. Population size plays a crucial role in determining water availability. For instance, China, with a population exceeding 1.3 billion, has a water availability of approximately 2 800 km3, resulting in about 2 300 m3 per person per year. In contrast, with only 0.60 km3 of water available, Singapore has a supply of approximately 110 m3 per person per year. These examples demonstrate that a country with ample water resources may still face water scarcity challenges, and vice versa.

On the other hand, Mauritius, despite being categorised as a country with limited water resources, has an availability of approximately 2 km3 of water. Surprisingly, this is sufficient to meet the needs of its population of 1.3 million, providing around 1 700 m3 per person per year.

Source: https://www.pexels.com/search/water/lisafotios

"Water is the driving force of all nature."

• Leonardo da Vinci

Water scarcity can arise due to insufficient rainfall and/or significant evaporation rates, known as physical water scarcity. Another cause of water scarcity is economic limitations. Even if a country possesses abundant water resources, it may face challenges in terms of affordability to extract, treat and distribute water for its population, leading to economic water scarcity.

Even if water is accessible, it may not be safe to drink (potable). Ensuring the potability of water involves various methods, all of which are based on two fundamental principles:

• Sanitation systems are implemented to prevent the contamination of clean water with dirty water, ensuring that they remain separate and safeguarding water intended for human use

• Water treatment processes are employed to guarantee the safety of drinking water supplied to individuals, ensuring that it is free from harmful contaminants.

Globally, there remains a significant lack of access to sanitation facilities and clean water for many people. In 2000, the United Nations set a goal to halve the proportion of the population without sustainable access to safe drinking water and basic sanitation by 2015. Although progress has been made, with 2.1 billion individuals gaining access to improved sanitation, there are still 2.4 billion people using inadequate sanitation facilities. Alarmingly, 946 million individuals continue to practice open defaecation, leading to the prevalence of diseases. Shockingly, a child loses their life every 2.5 minutes due to illnesses associated with open defaecation.

In certain less economically developed countries (LEDCs), the proportion of the population with access to safe water is less than 25%. Conversely, in regions like Europe and North America, it is commonly assumed that 100% of the population has access to safe water.

Access to safe water not only varies between countries but also within countries themselves. One significant disparity exists between rural and urban areas in terms of water accessibility.

In numerous cities and towns, a greater number of individuals have access to clean water and improved sanitation compared to rural areas within the same country. The primary factors contributing to this disparity are:

• Urban areas tend to have a higher concentration of wealth and a larger population of affluent individuals compared to rural areas.

• Significant numbers of people in urban areas can unite and exert collective pressure on authorities to ensure the provision of safe water. The concentrated population and organised activism in cities allow for more effective advocacy and demands for improved water infrastructure and services.

• The installation of piped water systems is generally more cost-effective in densely populated urban areas compared to scattered rural communities. The proximity of many individuals in urban settings allows for more efficient distribution networks, reduced infrastructure costs and economies of scale. In contrast, providing piped water to rural communities with dispersed populations involves greater challenges and expenses due to longer distances, difficult terrain and the need for extensive infrastructure development.

On a larger scale, disparities in water availability can potentially escalate into conflicts, known as water wars. Currently, these conflicts are relatively limited in scope. Tensions exist over the utilisation of the River Jordan in the Middle East, as well as around the Aral Sea in Asia involving countries such as Kazakhstan, Uzbekistan, Turkmenistan, Tajikistan and Kyrgyzstan. However, with growing populations and evolving cultures, it is anticipated that more regions may experience similar tensions and even the possibility of armed conflict related to water resources.