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Social science fa4 (1)


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Social science fa4 (1)

  1. 1. 1. To keep rates low. Maximizing current water supplies helps defer the need to develop new, more expensive sources of water. 2. To prepare for a drought. Many areas of the country have experienced drought conditions in the past few years. Water conservation helps prepare for these worst of times. 3. To comply with regulations. Many states and local regulators have established efficient water use regulations. 4.To save money. Lower consumption means lower water bills. 5. It is a resource that is a benefit to everyone.
  2. 2. What is it? Rainwater harvesting is the accumulation and deposition of rainwater for reuse before it reaches the aquifer. Advantages :- Rainwater harvesting provides an independent water supply during regional water restrictions . Promotes both water and energy conservation It helps in the availability of clean water by reducing the salinity and the presence of iron salts. Where in India is it practiced? Tamil Nadu Rajasthan Kerala
  3. 3. How is it done? Rainwater harvesting is done in 3 steps:1. Collecting and transporting water- done through catchment areas and conduits. 2. Filtration -A filter unit is a chamber filled with filtering media to remove debris and dirt from water before it enters the storage tank or recharge structure. 3. Storage in tanks for recharging the groundwater- harvested water is stored in tanks which is later used to recharge groundwater.
  4. 4. What is sustainable development? Sustainable economic development or sustainability means that ‘development should take place without damaging the environment, and development in the present should not compromise with the needs of the future generations’. Reasons for groundwater depletion :-  The primary cause of groundwater depletion is sustained groundwater pumping. We are pumping out water at a faster rate than it is getting replenished.
  5. 5. Effects of groundwater depletion :- 1. Lowering of the water table– caused by excessive pumping. 2. Increased costs- as the water table lowers, water must be pumped farther to reach the surface, using more energy. 3. Land subsidence- Land subsidence occurs when there is a loss of support below ground. Ways to conserve groundwater :- 1. Reduce chemical use- we should minimize chemical use. 2. Manage waste- waste disposal should be watched over. 3. Save water- close the taps when not in use.
  6. 6. India’s growth story has been impressive so far with industry and service sectors being the growth drivers. Along with industrial and population growth, the demand for water also increases. Unpredictable rainfall patterns because of climate change, depleting water resources because of extreme groundwater extraction, contamination of available surface/groundwater resources due to discharge of untreated sewage, and/or industry effluents have had an impact on water quantity and quality. Per capita water availability is expected to reach 1,140 cubic meters by 2050 from 1,820 cubic meters in 2001. As India’s water problems are self-inflicted, the need to adopt sustainable water management practices is crucial.
  7. 7. With mounting water issues, municipalities are under stress to provide water (potable and nonpotable) to industrial, commercial, and residential segments. Though wastewater recycling and reuse is an option to meet water requirements, some factors are limiting its use, such as:• High price sensitivity towards advanced wastewater treatment systems. • Negative perception about wastewater recycling . • Lack of technological awareness and skilled manpower . • Fragmented nature of the market. • Weak enforcement of regulations and policies.
  8. 8. There are many ways to recycle water. Out of which some are stated below :1. Use gray water on garden and plantsGray water is termed for water which is already used. 2. Use sink water to flush toilet waste. 3. Harvest rainwater- this will help us save a considerable amount of water. 4. Reuse water that drains out of flower pots. 5. Save kitchen water.
  9. 9. Objective :- Narmada Bachao Andolan (NBA) is a social movement against a number of large dams being built across the Narmada river. It aims to stop the building of such dams. Formation :- There were groups such as Gujarat-based Narmada Asargrastha Samiti (Committee for people affected by the Narmada dam), Madhya Pradesh-based Narmada Ghati Nav Nirman Samiti (Committee for a new life in the Narmada Valley) who either believed in the need for fair rehabilitation plans for the people or who vehemently opposed dam construction despite a resettlement policy.
  10. 10. People involved :- Amongst the major celebrities who have shown their support for Narmada Bachao Andolan are Booker Prize winner Arundhati Roy and Aamir Khan Ways to pressurize the government:- Within the focus of Narmada Bachao Andolan towards the stoppage of the Sardar Sarovar dam, Patkar advised addition of World Bank to their propaganda. Using the right to fasting, she undertook a 22-day fast that almost took her life. In 1991, Patkar's actions led to an unprecedented independent review by the World Bank.
  11. 11. Supreme court’s decision :- The Supreme Court's decision is still pending, seeking stoppage of construction of the Sardar sarovar dam. The court initially ruled the decision in the Andolan's favor, thereby effecting an immediate stoppage of work at the dam and directing the concerned states to first complete the rehabilitation and replacement process.
  12. 12. This is the most traditional and reliable source of energy. A quarter of our energy requirement is fulfilled by hydro power plants. The kinetic energy of flowing water or the potential energy of water at a height is used. Hydro power plants convert the potential energy of falling water into electricity. There are not many waterfalls for hydro power generation. Therefore, it mainly depends on dams. How do hydro power plants work:- To produce hydel electricity, high rise dams are constructed on the river to obstruct the flow of water and thereby collect water in large reservoirs. The water level rises and in this process the kinetic energy of flowing water gets transformed into potential energy. The water from the high level in the dam is carried through pipes, to the turbine at the bottom of the dam.
  13. 13. Due to the gravitational pull of mainly the moon on the spinning earth, the level of sea water rises and falls. This phenomenon is called high and low tides and the difference in sea level gives us the tidal energy. It is harnessed by constructing a dam across a narrow opening to the sea. A turbine fixed at the opening of the damn converts tidal energy to electricity. But, the locations where these dams can be built are limited.
  14. 14. Due to geological changes, molten rocks formed in the deeper hot regions of earth’s crust are pushed upward and trapped in certain regions called ‘hot spots’. When underground water comes in contact with the hot spot, steam is generated. Sometimes hot water from that region finds outlets at the surface. Such outlets are known as hot springs. The steam trapped in rocks is routed through a pipe to a turbine and used to generate electricity. There are very few commercially viable sites where such energy can be exploited. There are many geothermal power plants in New Zealand and United States of America.
  15. 15. What is ‘hard water’? Perhaps you must have noticed mineral deposits on your cooking dishes, or rings of insoluble soap scum in your bathtub. These are signs of hard water from the municipal water supply. Hard water is water that contains cations with a charge of +2, especially Ca2+ and Mg2+. These ions do not pose any health threat, but they can engage in reactions that leave insoluble mineral deposits. These deposits can make hard water unsuitable for many uses, and so a variety of means have been developed to "soften" hard water. Problems with hard water :- Mineral deposits are formed by ionic reactions resulting in the formation of an insoluble precipitate. For example, when hard water is heated, Ca2+ ions react with bicarbonate (HCO3) ions to form insoluble calcium carbonate (CaCO3)
  16. 16. Some strategies to soften hard water:- Household water softeners typically use a different process, known as ion exchange. Ion-exchange devices consist of a bed of plastic (polymer) beads covalently bound to anion groups, such as -COO-. The negative charge of these anions is balanced by Na+ cations attached to them. When water containing Ca2+ and Mg2+ is passed through the ion exchanger, the Ca2+ and Mg2+ ions are more attracted to the anion groups than the Na+ ions. Hence, they replace the Na+ ions on the beads, and so the Na+ ions (which do not form scale) go into the water in their place.
  17. 17. When hard tapwater passes through the ion exchanger (left), the calcium ions from the tapwater replace the sodium ions in the ion exchanger. The softened water, containing sodium ions in place of calcium ions, can be collected for household use. Unfortunately, many people with high blood pressure or other health problems must restrict their intake of sodium. Because water softened by this type of ion exchange contains many sodium ions, people with limited sodium intakes should avoid drinking water that has been softened this way. Several new techniques for softening water without introducing sodium ions are beginning to appear on the market.