Water

File:Water glas.jpeg

A glass of water

Water (chemical formula: H₂O) is a compound made of two hydrogen atoms and one oxygen atom. In other words: H₂O is a water molecule consisting of two H atoms (hydrogen) and one O atom (oxygen).

What is water used for?

All life on Earth consists largely of water. About 70% of the world is covered with water, and the human body is about 65% water. Life on Earth depends on water; without it, life would not be possible.

In what forms can water exist?

Water exists in three states: ice, liquid water, and water vapor. These correspond to solids, liquids, and gases. Ice melts at 0°C and water boils at 100°C. Water can also evaporate at lower temperatures, such as puddles drying after rain. These changes are important in the water cycle.

Water can be fresh (tap water) or salty (seawater). When fresh and salt water mix, it is called brackish water.

How did water come to Earth?

Billions of meteoroids containing ice fell to Earth over a period of 150 million years. Over time, this contributed to the formation of the first seas.

Where can you find water?

Almost everything on Earth contains water. People often think of water from taps, rivers, or lakes. Water flows through many natural and man-made systems: streams, rivers, lakes, seas, oceans, canals, and more. Some waterways are natural; others, like certain canals and lakes, were created by humans. The IJsselmeer is an example of a body of water transformed by people.

Clean drinking water

Water extraction area Access to clean drinking water has increasingly been recognized as a human right since 2000. The soil acts as a natural filter for groundwater. In the Netherlands, dune areas help filter drinking water. Signs reading “water extraction area” indicate protected zones where pollution could threaten clean water.

Due to climate change, clean drinking water is becoming scarcer worldwide. Protecting nature reserves and Natura 2000 areas also protects water sources.

How much water is on Earth?

There are about 1.6 billion cubic kilometers (km³) of water on Earth.

What role does water play in daily human life?

Water is essential for humans. Since the human body is about 65% water, people need to drink about 2 liters per day. Without water, a person can survive only about four days.

About 97% of Earth’s water is salty. Less than 2% is frozen in glaciers and ice caps. Only about 0.5% is fresh or brackish water.

Because the total amount of water on Earth stays the same, it is continuously reused through the water cycle.

People use water daily for flushing toilets, showering, brushing teeth, washing hands, and cooking. In the Netherlands, the average person uses about 112 liters per day.

Agriculture also uses large amounts of fresh water—about 125 billion liters per year.

Clean fresh water is needed every day. According to Rijkswaterstaat (2016), clean water is healthy, suitable for drinking, and rich in plants and animals.

Sewage systems began in the late Middle Ages, helping remove polluted water. Today, pollution from factories, ocean waste, and ecological imbalance still threatens water quality.

In the 19th century, the Netherlands began building water basins and pipelines. Dune sand helped filter the water.

Rijkswaterstaat manages major waters, dikes, bridges, and locks. Water boards manage regional waterways.

What dangers exist in the Dutch water landscape?

The Netherlands is a delta country, formed by the Rhine, Meuse, and Scheldt rivers. Much of the country lies below Normaal Amsterdams Peil (NAP), roughly equal to average sea level of the North Sea.

The country is protected by dikes, storm surge barriers, and dunes, but flooding can still occur. Another danger is salinization when seawater enters the soil.

Floods and storm surges

A storm surge occurs when wind pushes seawater above a certain threshold—1.5 meters above average high tide along the Dutch coast. Storms from the northwest pose the greatest risk. Large rivers can also flood due to heavy rainfall or melting snow.

Water nuisance and water storage

Heavy or prolonged rainfall can cause water nuisance when the soil or sewer system cannot absorb the water. This happens especially in cities with lots of pavement.

People create small gardens by removing paving stones, and cities build rooftop gardens and underground water storage. Greener cities also help reduce heat during summer by preventing urban heat island effects.

In rural areas, long periods of rain can saturate the soil, causing fields to flood. After droughts, soil can become compacted, preventing water absorption. Some soils, like river clay, naturally drain poorly.

Sea level rise

As global temperatures rise, glaciers and ice caps melt faster than new ice forms. Water also expands when warmed. This contributes to sea level rise. More dike reinforcement will be needed in the future.

Land subsidence

Land subsidence causes more areas to fall below sea level. This happens especially in old peat polders such as around Gouda. Houses may sink, and wooden foundation piles can rot when exposed to air.

Too much water drainage

Because the Netherlands focuses heavily on draining water, shortages can occur during dry periods. Water can be stored in certain areas, and rivers can be temporarily dammed to retain water.

Proverbs

• Launching a ship = to set afloat
• To come above water again = to reappear after being lost
• Carrying water to the sea = doing useless work
• To add water to the wine = to lower one’s demands
• The party fell into the water = the event failed (due to severe weather)

External links

• Webpad water
• Dike reinforcement: Ministry of Infrastructure and Water Management
• Related: Netherlands safe for now, but must adapt to salinization

Other projects on this topic

• Water, on Wikibooks