Water Resources
Topics to be covered - 1. Water 2. Fresh water. 3. Water scarcity 4. Causes and types. 5. Dams 6. Advantages and disadvantage 7. Rainwater harvesting 8. Old and modern methods Water Three-fourth of the earth’s surface is covered with water but only a small proportion of it accounts for freshwater, that can be put to use. Water is a renewable resource. Fresh water: 96.5 per cent of the total volume of world’s water is estimated to exist as oceans and only 2.5 per cent exists as fresh water. 70 per cent of the fresh water occurs as ice sheets and glaciers in Antarctica, Greenland and the mountainous regions of the world. Less than 30 per cent is stored as groundwater in the world’s acquirers. Fresh water is mainly obtained from surface run off and ground water. This is continually being renewed and recharged through the hydrological cycle. All the water moves within the hydrological cycle making water a renewable resource. Three fresh water sources are: Precipitation—from rainfall; Surfa...