Сборник материалов международной научной конференции студентов, магистрантов, аспирантов

Д.С. Петрушко, М.Н. Трубчик

Республика Беларусь, Брест, БрГУ имени А.С. Пушкина

Научный руководитель – А.С. Поплавская

THE IMPORTANCE OF FRESH WATER

Fresh water is necessary for all living species on Earth, after all, that is the only thing that sets this planet apart from others. Seeing water everywhere, and having it readily available in the developed world, has made water seem like an abundant commodity. This notion, however, couldn’t be more false. The water that covers the surface of our planet is 97% saline water, the other 3% of fresh water, which is the resource we rely on most, is found in surface water (0.3%), ground water (30.1%), icecaps and glaciers (68.7%), and others (0.9%), such as water vapor and clouds. From the surface water that is utilized, much of it is found in lakes (87%), swamps (11%) and rivers (2%).

Ocean water may cover more than 70 percent of the Earth’s surface, but thirsty humans rely on finite supplies of freshwater to stay alive. And with exploding human population growth, especially in poor countries, these finite supplies get quickly spoken for. Further, in places without proper sanitation, water can become tainted with any number of diseases and parasites. According to the World Bank, as many as two billion people lack adequate sanitation facilities to protect them from water-borne disease, while a billion lack access to clean water altogether. According to the United Nations, which has declared 2005–2015 the “Water for Life” decade, 95 percent of the world’s cities still dump raw sewage into their water supplies.

Thus it should come as no surprise to know that 80 percent of all the health maladies in developing countries can be traced back to unsanitary water. Developed countries aren’t immune to freshwater problems either. Researchers found a six-fold increase in water use for only a two-fold increase in population size in the United States since 1900. Such a trend reflects the connection between higher living standards and increased water usage, and underscores the need for more sustainable management and use of water supplies even in more developed societies.1.8 billion people who have access to a water source within 1 kilometer, but not in their house or yard, consume around 20 liters per day. In the United Kingdom the average person uses more than 50 liters of water a day flushing toilets (where average daily water usage is about 150 liters a day. The highest average water use in the world is in the US, at 600 liters day.)

Since 1970, freshwater species have seen a 50 percent decline. More than a billion people lack access to clean water, and 2.6 billion people don’t have access to clean sanitation. No clean sanitation means a polluted water supply and tainted freshwater sources. On average 4,500 children die per day due to unsafe water and inadequate hygiene. Close to half of all people in developing countries suffer at any given time from a health problem caused by water and sanitation deficits. Agriculture accounts for a whopping 70 percent of our freshwater use. Water is indispensable for farming.

Dams allow us to store water in a reservoir during a wet season and then release it as needed during a dry season. However, dams also divert water flow patterns, which affects the habitats of local birds and fish and can obstruct fish migration, reducing spawning. Dams and flow diversion disrupt natural flooding cycles, reduce water flow, drain wetlands, increase flood risk and threaten species.

The agriculture industry’s poor drainage and irrigation systems also squander precious water. The World Wildlife Fund estimates that only 20 to 50 percent of water extracted for farming actually reaches the crops. With traditional flood irrigation systems, farmers pump or manually bring water to the fields where it simply flows through the crop area. If the fields aren’t flat, water ends up pooling in the lower areas and misses the higher areas altogether. Switching to a more efficient method of irrigation could save water – a good thing for freshwater habitats that are being sucked dry. For example, drip irrigation is a much more controlled method of watering, where water slowly trickles from feeder hoses to very specific areas.

But many countries grow crops that are unsuitable for the local climate and soil, often because government subsidies make growing those crops profitable. When overproduction occurs, the soil salinity (saltiness) increases and it becomes more difficult to grow hardy crops and raise cattle. In turn, farmers start using pesticides and chemicals to help their crops grow. The pesticide chemicals then wash into the remaining water sources, destroying freshwater habitats and the species that live there. In fact, the polluted runoff can wash all the way to the coast and even begin to affect the marine ecosystem. With world population expected to pass nine billion by mid-century, solutions to water scarcity problems are not going to come easy. Some have suggested that technology – such as large-scale saltwater desalination plants – could generate more freshwater for the world to use. But environmentalists argue that depleting ocean water is no answer and will only create other big problems. In any case, research and development into improving desalination technologies is ongoing, especially in Saudi Arabia, Israel and Japan. And already an estimated 11,000 desalination plants exist in some 120 countries around the world.

As individuals, we can all rein in our own water use to help conserve what is becoming an ever more precious resource. We can hold off on watering our lawns in times of drought. And when it does rain, we can gather gutter water in barrels to feed garden hoses and sprinklers. We can turn off the faucet while we brush our teeth or shave, and take shorter showers. Doing more with less is the first and easiest step along the path toward water security.

1. 
   What’s the biggest threat to freshwater habitats? [Electronic resource] // Adventure. – Mode of access: http://adventure.howstuffworks.com/outdoor-activities/fishing/fish-conservation/fish-populations/freshwater-habitatthreat.htm. – Date of access: 24.02.2015.
   

В статье речь идет о значимости пресных вод для функционирования и поддержания жизнедеятельности всех живых существ на Земле, в том числе и человека.