WATER: A PRESIOUS RESOURCE | SPEED NOTES | SCIENCE | CBSE | CLASS 7

Chapter – 16 Water: A Precious Resource Water is essential for all living beings. No onecan imagine lifewithout water. Water exists in three forms: solid, liquid andgas. Solid: At polesof earth, snow-covered mountains and glaciers. Liquids: In oceans, lakes, rivers and underground. Gaseous: Water vapors in air. Surface water: Sea and oceans, Rivers, Springs, Lakes and Ponds. Ground water: It isthe water thatsweeps into theground through soiland collects over non-porous rocks (aquifer). Level of groundwater at any place is called water table. Groundwater gets recharged by seepage of water into the ground (infiltration). Waterscarcity: Depletion ofwater table. Reasons forscarcity of water Increase population decreases open areas which decreases seepage of rainwater. Increasing industries more water isdrawn out fromground. Agricultural activities irrigation systems faildue to erratic rainfall which results in increased useof ground water. Uneven distribution of rainfall. Scanty rainfall. Deforestation. Though wateris maintained by the watercycle, yet thereis an acutescarcity of waterin many parts of the globe. There is an uneven distribution of water. Most of ithas been resulted from human activities. Rapid growth of industries, increasing population, growing irrigation requirements and mismanagement are some ofthe causes forwater shortage. We need to be worried about the wastage during the supplyof water through pipes,

the leaking tapsin buildings andother places. Unnecessary use ofwater and overdrawing from groundwater should be avoided. Recharge of water tothe ground should be increased. The need ofthe hour isthat every individual should use water economically. Plants wiltand ultimately dry-up if they arenot watered fora few days.