Water is life

Water is the natural resource we all know very well. One cannot live without it. We know it’s many forms - rain, snow, ice, hail, vapour, fog. Yet, water is the natural resource we least understand.

How does water get into the clouds? What happens when it reaches the Earth? Why is there sometimes too much and other times too little of it? And, most important, is there enough water for all the plants, and all the animals, and all the people? Water covers nearly three fourths of the Earth, most being sea water. But seawater contains salts, including those that are harmful to most land plants and animals. Still, it is from the salty seas and oceans that most of our fresh water comes - no longer salty and harmful. Water moves from clouds to land and back to the ocean in a never-ending cycle. Ocean water evaporates into atmosphere leaving salts behind, and moves across the Earth as water vapour. Water in lakes and rivers also evaporates and rises into the air.

Having cooled in the air the water vapour condenses and falls to the Earth as rain, hail or snow, depending on region, climate, season and topography. This part of the cycle is very important because man can use water stored in the atmosphere only when it falls to the land.

Every year about 450, 000 cubic kilometres of water evaporates from the oceans and about 61, 000 cubic kilometres from land sources. Water is an unchanging and ever renewing, resource, but its distribution on the surface of the globe varies greatly - there is either too little or too much water. Many problems are caused by too much water when we do not need it or too little when we want it. No natural resource on our planet has so many uses as water. We need water to support our lives, to grow our crops, to water our stock, to power our industries and for many other purposes.

There is plenty of water on the Earth. Man's activity is accelerating the process of water pollution, the amount of fresh water available to use is decreasing rapidly.

Measures must be taken against waste of water and pollution of water. We have to improve methods of irrigation in order to use water more efficiently.

In the recent decades the problem of water supply to people and economics has become extremely urgent. The depletion of such water resources as surface water and ground water is inevitable.

Water resources are continuously renewed within the hydro-logical cycle. But with the abundance of water in the technological processes in major industries non-returnable losses of fresh water may increase its shortage. Building dams, reservoirs and canals is the important factor of the transformation of the hydrological regime. An essential measure is the conservation of water by all possible means, so as to decrease its expenditure per unit of production until " dry" technologies are established. It is very important to combat the pollution of rain and snow-melt water through the use of herbicides, pesticides and other toxic chemicals. Settling basins should be built to collect the most polluted run-off water especially at the beginning of snow-storms and during snow melt.

It is advisable to use industrial wastewater for field irrigation. This measure is of importance since soil is a very favourable medium for rendering waste water harmless especially if used with small irrigation norms. Thus, waste water which is harmful when discharged into rivers and reservoirs becomes useful. Irrigation can be applied to increase soil moisture, to protect plants from frosts and dry winds, to apply fertilizers. Another measure is the conversion of industrial and heat power generation to closed-recirculating water-supply systems, which do riot require water of high quality. This method of rendering waste waters harmless must form an integral part of production technology.