On March 22 we celebrate World Water Day. It is a day when those who are lucky to enjoy daily clean water on demand, often taken it for granted, should stop for a moment to think about those millions of people who still suffer from water shortage.

Today, we also have a look at how satellites help from space addressing water scarcity in the hope that this knowledge can provide ideas for solutions that can be implemented in the near future.

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World Water Day

March 22 is the day when the United Nations (UN) propose a global instrospection on the importance of freshwater and promotes its sustainable management.

World Water Day was founded by the United Nations General Assembly on March 22, 1993. In 2019, World Water Day focuses on the UN Sustainable Development Goal 6 (SDG 6).

The UN Sustainable Development Goal 6: Water for All by 2030

The Sustainable Development Goal 6 aims to ensure the availability and sustainable management of water for everyone on the planet by 2030.

More than two billion people are still living without safe water. Around four billion people are suffering severe water scarcity for at least one month a year. Despite water being a human right --and something without which humans, animals, and plants cannot survive-- achieving water for all is a huge challenge, even in the 21st century.

This challenge does not seem to get better in the future due to a growing global population and the consequences of climate change. In fact, this challenge could become even more challenging in the next few decades. Unless there is a real change in human mentality and immediate global action, the future of freshwater supply may become uncertain.

The cycle of water

The same water we consume today has existed for billions of years. Water cycles through the air, oceans, lakes, rocks, animals, plants, and back again.

Defying the laws of chemistry, water is the only known substance that exists naturally as a gas, liquid, and solid within a relatively small range of air temperatures and pressures found on the surface of planet Earth.

From the totality of water on Earth, less than three percent is freshwater. The vast majority of this three percent of water is locked up in icecaps and glaciers. This leaves only less than one percent of water available for drinking, washing, and other domestic needs, agriculture and industrial processes, and other needs that require freshwater.

Satellites are helping to understand and measure the processes driving the water cycle. They also show the impact that human activity and climate change have in the disruption of the cycle.

Satellites have detected dwindling water bodies, as shown in the Europen Space Agency's animation below. We are running out of the most important natural resource on Earth. If this continues without a proper and effective management of water supplies, it can cause life-threatening crises.

How satellites monitor water levels and water scarcity from space

Earth-observing satellites can help the global water resources challenge from space. The European Space Agency (ESA) animation above shows water levels in the Theewaterskloof Dam in South Africa’s Western Cape Province. It is evident how water levels have dropped dramatically over recent years.

The dam is the major source of water for domestic and agricultural uses in the region. The lack of water has caused the production of grain to drop by more than 36 percent. The production of wine grapes has dropped by 20 percent.

Scientists have estimated that the dam needs to receive at least three years of good winter rainfall to return to its earlier healthy water level.

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Thanks to the TIGER initiative, the Stellenbosch University is applying Machine Learning algorithms to data from the Copernicus Sentinel-1 and Sentinel-2 missions to carefully monitor the situation in real-time.

According to ESA, satellites such as ESA's SMOS mission and the Copernicus Sentinels provide key information on soil moisture and crop health.

Since around 70 percent of the freshwater is used for agriculture, this information can be used in order to improve the efficiency of irrigation practices.

The Sentinel-2 mission collects data that is paramount to the Copernicus Land Monitoring Service. This service provides geographical information such as changes on land cover, land use, vegetation state, water cycle, and surface-energy variables for a broad range of users across the world.

The satellites Copernicus Sentinel-1, Sentinel-2, and ESA's CryoSat also monitor glacial change, which provides information on the real impact on water supplies downstream.

Part of the Himalayas, for instance, provides freshwater for over 1.3 billion people in Asia; this is nearly 20 percent of the total world's population. These high-altitude ice fields contain the largest reserve of freshwater ouside the North and South Poles.

Technologies developed for human space missions have proven to be also beneficial to serve global needs, especially those needs in harsh environments in certain regions on the planet.

WADItech: The EU project that detects water leaks

"The trouble with water is that they're not making any more of it." --Marq de Villiers: Water: The Fate of Our Most Precious Resource

European Union funded project WADItech is testing a new airborne water leak detection surveillance system that could save water flowing in the supply system from getting lost due to leaks. In some European countries alone, half of the water resources gets lost.

This leak detection surveillance system developed by the EU WADI project applies optical remote sensing devices that use multi-spectoral and infrared cameras located on planes and drones. With a combination of manned and unmanned aircraft monitoring it is possible to cover both long distance infrastructure and remote or dangerous areas.

The WADI airbone water leak detection surveillance service is based on three fundamental pillars:

Optical remote sensing

Manned and unmanned aerial platforms

Demonstration in operational environment

Because water losses have a high environmental impact the implementation of systems that can be able to prevent unnecessary leaks and losses of water are important for the future preservation of freshwater resources. The water leak detection surveillance method is currently being tested in France and Portugal.