Water

A globule of liquid water, and the concave depression and rebound in water caused by something dropping through the water surface.

Water (chemical formula H₂O) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a solvent). It is vital for all known forms of life, despite providing neither food, energy, nor organic micronutrients.

A number of natural states of water exist. It forms precipitation in the form of rain and aerosols in the form of fog. Clouds consist of suspended droplets of water and ice, its solid state. When finely divided, crystalline ice may precipitate in the form of snow. The gaseous state of water is steam or water vapor. Water covers about 71% of the Earth's surface, mostly in seas and oceans, about 96.5%.

Fishing in salt and fresh water bodies is a major source of food for many parts of the world, providing 6.5% of global protein. Large quantities of water, ice, and steam are used for cooling and heating, in industry and homes. Water is an excellent solvent for a wide variety of substances both mineral and organic; as such it is widely used in industrial processes, and in cooking and washing.

Collection

Wells

A well is an excavation or structure created in the ground by digging, driving, or drilling to access liquid resources, usually water. The oldest and most common kind of well is a water well, to access groundwater in underground aquifers. The well water is drawn up by a pump, or using containers, such as buckets or large water bags that are raised mechanically or by hand. Water can also be injected back into the aquifer through the well. Placing a lining in the well shaft helps create stability, including wood linings.

Wells have traditionally been sunk by hand digging, and it is still currently the case in rural areas. These wells are inexpensive and low-tech as they use mostly manual labour, and the structure can be lined with brick or stone as the excavation proceeds. A more modern method called caissoning uses pre-cast reinforced concrete well rings that are lowered into the hole. Driven wells can be created in unconsolidated material with a well hole structure, which consists of a hardened drive point and a screen of perforated pipe, after which a pump is installed to collect the water. Deeper wells can be excavated by hand drilling methods or machine drilling, using a bit in a borehole. Drilled wells are usually cased with a factory-made pipe composed of steel or plastic. Drilled wells can access water at much greater depths than dug wells.

Two broad classes of well are shallow or unconfined wells completed within the uppermost saturated aquifer at that location, and deep or confined wells, sunk through an impermeable stratum into an aquifer beneath. A collector well can be constructed adjacent to a freshwater lake or stream with water percolating through the intervening material. The site of a well can be selected by a hydrogeologist, or groundwater surveyor. Water may be pumped or hand drawn. Impurities from the surface can easily reach shallow sources and contamination of the supply by pathogens or chemical contaminants needs to be avoided. Well water typically contains more minerals in solution than surface water and may require treatment before being potable. Soil salination can occur as the water table falls and the surrounding soil begins to dry out. Another environmental problem is the potential for methane to seep into the water.

Dams

A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use, aquaculture, and navigability. Hydropower is often used in conjunction with dams to generate electricity. A dam can also be used to collect or store water which can be evenly distributed between locations. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees, also known as dikes, are used to manage or prevent water flow into specific land regions.

Snowmelt

See also: Snow

The melting of snow or ice releases water, including in glacial ice, tabular icebergs and ice shelves over oceans. Meltwater is often found in the ablation zone of glaciers, where the rate of snow cover is reducing, and it can be produced during volcanic eruptions. When meltwater pools on the surface rather than flowing, it forms melt ponds. As the weather gets colder meltwater will often re-freeze. Meltwater can collect or melt under the ice's surface. These pools of water, known as subglacial lakes can form due to geothermal heat and friction.

Meltwater provides drinking water for a large proportion of the world's population, as well as providing water for irrigation and hydroelectric plants. This meltwater can originate from seasonal snowfall, or from the melting of more permanent glaciers. Climate change threatens the precipitation of snow and the shrinking volume of glaciers.

Rain Basin

A rainwater tank, sometimes called a rain barrel, is a water tank used to collect and store rain water runoff, typically from rooftops via pipes. Rainwater tanks are devices for collecting and maintaining harvested rain. Rainwater tanks are installed to make use of rain water for later use, reduce mains water use for economic or environmental reasons, and aid self-sufficiency. Stored water may be used for watering gardens and agriculture, as well as for drinking, especially when other water supplies are unavailable, are expensive, or of poor quality, and when adequate care is taken that the water is not contaminated and is adequately filtered. Underground rainwater tanks can also be used for retention of stormwater for release at a later time and offer a variety of benefits described in more detail below. In arid climates, rain barrels are often used to store water during the rainy season for use during dryer periods.

Small scale rain barrels can be recycled from food storage and transport barrels, as well whiskey and wine aging barrels. Low cost designs also exist that allow the use of locally available materials and village level technologies. While most systems are properly engineered to screen out mosquitoes, the lack of proper filtering or closed loop systems may create breeding grounds for larvae. With tanks used for drinking water, if maintenance is not carried out, the user runs a health risk.

Evapotranspiration

Evapotranspiration is the combined processes by which water moves from the earth's surface into the atmosphere. It covers both water evaporation (movement of water to the air directly from soil, canopies, and water bodies) and transpiration (movement of water from the soil, through roots and bodies of vegetation, on leaves and then into the air). Evapotranspiration is an important part of the local water cycle and climate, as well as measurement of it plays a key role in agricultural irrigation and water resource management.

Purification

Water must be purified for human consumption whenever it is believed that it can be contaminated, including when staying in the wilderness. The process kills germs and removes both sediments and contaminants, making it safe for drinking.

One of the best ways to kill harmful microorganisms in the water, including bacteria, viruses, and parasites, is by boiling the water. While boiling alone will not remove heavy metals or chemical contaminants from the water, boiling it with the core inside cactus leaves, called mucilage, can potentially remove additional pollutants, such as arsenic.

Studies have found the effectiveness of some plants to remove pollutants from water. Specifically, pine trees can remove pathogens from the liquid. For this, remove a small branch from a pine tree, strip it from its bark and place the branch in the container with the water that needs purifying. The sap in the stick should trap and collect pathogens in the water. Likewise, cilantro can be effective at removing lead and nickel from water. In this case, place a handful of leaves in the container, stir the water and let the leaves sit in the water for at least an hour, removing and discarding them before drinking the water. Cilantro has not tested for the removal of other heavy metals, including arsenic and mercury.

Desalination

Salt water from sources such as seawater has concentrations much higher than the human body's capacity to process it. Kidneys can only make urine that is less salty than salt water, and as such people urinate more water than what was drank to get rid of the excess salt, risking the person's dehydration.

In order to survive in a situation where salt water is only available, a desalination method is needed. One of the simplest methods is through condensation: salt water is collected in a container, such as a bowl, is afterwards placed under direct sunlight, placing a smaller container to collect the desalinated water, such as a cup, and a material that allows for condensation is placed over the container, such as a plastic wrap, which must be tightly placed into the borders of the container to prevent open areas. A weight can be placed on top of the cover to the collection easier, such as a stone. The water should evaporate under the heat, and after several hours droplets will form in the cover, which should drop in the smaller container. The distilled water is safe for drinking.

Treatment

Three wastewater clarifiers from above, with skimmers shown

Water treatment is extremely important to human health, especially in high density environments, and is responsible for one of the largest gains in human life expectancy, on par with antibiotics and germ theory.

At its core, water treatment consists of three component processes. These are settlement, filtration, and disinfection.

Settlement

Settlement operates mainly on the principle of gravity, and focuses on channeling water into large containers called clarifiers with high volume and surface area. Water spends a long time in the clarifier, where solid particles suspended in the water are allowed to settle to the bottom and accumulate, forming a sludge layer that can be removed at a later time. A preparatory step to this process called flocculation is key to settlement, because it is during this step that coagulants are added to the water, allowing small particles to bind together and form larger, heavier particles that will settle to the bottom of the clarifier more quickly. The water in a clarifier is cleanest near the top, where the surface can be skimmed of any floating particles and where the water can be allowed to flow over a weir an into the next process station.

During filtration, water passes through filters, some made of layers of sand, gravel, and charcoal that help remove even smaller particles.

Filtration

The next step is filtration. Filtration has two components, biological and physical. Physical filtration is relatively straightforward. Water is flown over a semi-permeable surface, such as cloth or a bed of sand and crushed charcoal. Particles that remain in the water after clarification are then caught either because they are too large to fit through the holes in the surface or because they bind to the surface of the sand/charcoal. The sand/charcoal bed also provides a medium for friendly bacteria to form colonies and make biofilms, so that they can process any dissolved nutrients such as nitrogen or phosphorus out of the water and release it as carbon dioxide. In order to treat waters that contain dissolved metals, a bed of ionic sand can be used, which form bonds with the dissolved metals and capture them in the process. In treatment of extremely nutrient dense waters such as wastewater, aeration may be effective in feeding these bacteria oxygen, accelerating the rate at which they digest these nutrients.

Shown here is a simple distillation apparatus, where the dirty water is heated by the burner, turns to steam, and then condenses in the second bulb, which is kept cool by the water from the tap.

Disinfection

The last component is disinfection. Disinfection generally is done one of three ways, either using chlorination, ozone, or ultraviolet light. However, these methods are generally quite complicated to implement in a scenario where a manufacturing base is not readily available. Therefore, the simplest way to disinfect water is to boil and capture the resulting steam, thus distilling it. Although it is energy intensive, distillation can kill bacterial pathogens and denature viral threats quite effectively.

As transport

See also: wikipedia:Water#Transportation

Maritime transport, or ocean transport, is the transport of people (passengers) or goods (cargo) via waterways. Freight transport by sea has been widely used throughout recorded history. The advent of aviation has diminished the importance of sea travel for passengers, though it is still popular for short trips and pleasure cruises. Transport by water is cheaper than transport by air. Maritime transport accounts for roughly 80% of international trade.

Maritime transport can be realized over any distance by boat, ship, sailboat or barge, over oceans and lakes, through canals or along rivers. Shipping may be for commerce, recreation, or for military purposes. While extensive inland shipping is less critical nowadays, the major waterways of the world including many canals are still very important and are integral parts of worldwide economies. Particularly, any material can be moved by water; however, water transport becomes impractical when material delivery is time-critical, including various types of perishable produce. Still, water transport is highly cost effective with regular schedulable cargoes, such as trans-oceanic shipping of consumer products, and especially for heavy loads or bulk cargos, such as coal, ores, or grains. Arguably, the industrial revolution took place best where cheap water transport by canal, navigations, or shipping by all types of watercraft on natural waterways supported cost-effective bulk transport.

Seawater

Main Article: Seawater

Seawater in the Strait of Malacca, Peninsular Malaysia

Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L). This means that every kilogram (roughly one liter by volume) of seawater has approximately 35 grams (1.2 oz) of dissolved salts, predominantly sodium and chloride ions.

Dependencies

• Hydrogen
• Oxygen
  • Water
    • Ice
    • Snow
  • Chloride
  • Sodium
    • Seawater

See also

• Ammonia
• Fire
• Oil
• Tympanum
• Chemical compounds

External links

Purification

• Survival Skills: 10 Ways to Purify Water - Tim MacWelch, 3 October 2019, Outdoor Life
• 25 Great Ways How To Purify Water For Drinking - Joseph Bartley, 5 April 2021, All About Water Filters
• Safe Drinking Water - WikiHow
• 8 Fastest Ways to Purify Water - Alan Urban, Urban Survival Plan
• 10 Drinking Water Purification Methods - Survivalist 101
• Twenty-Five Methods To Purify Water - Environmental Alternatives

Desalination

• How to Desalinate Water - Guidecentral English, 24 June 2020, YouTube
• How to Turn Salt Water Into Drinking Water - 22 February 2022, WikiHow
• Desalination - Water Science School, 11 September 2019, United States Geological Survey
• Desalinate Sea Water - Sciencefairadventure.com

This article uses material from the Wikipedia article Water, which is released under the Creative Commons Attribution-ShareAlike 3.0 Unported License (view authors).

This article uses material from the Wikipedia article Water#Transportation, which is released under the Creative Commons Attribution-ShareAlike 3.0 Unported License (view authors).

This article uses material from the Wikipedia article Well, which is released under the Creative Commons Attribution-ShareAlike 3.0 Unported License (view authors).

This article uses material from the Wikipedia article Meltwater, which is released under the Creative Commons Attribution-ShareAlike 3.0 Unported License (view authors).

This article uses material from the Wikipedia article tank Rainwater tank, which is released under the Creative Commons Attribution-ShareAlike 3.0 Unported License (view authors).

This article uses material from the Wikipedia article Evapotranspiration, which is released under the Creative Commons Attribution-ShareAlike 3.0 Unported License (view authors).