Decarbonising Buildings: Making a net-zero built environment a reality
Water management in India: By Gita Kavarana
1. The value of a raindrop Programme for Oslo University students New Delhi, March 2007
2. 1. Growing crisis In 1950, water availability was very low only in North Africa, and was average or above average in the rest of the world. < 1 - catastrophically low; 1.1.-2.0 - very low; 2.1-5.0 - low; 5.1-10 - average; 10.1-20 - high; > 20 - very high. Source: Source: World water resources at the beginning of the 21st century” prepared in the framework of ihp unesco
3. 1. Growing crisis In 2001, more than 75% of the world population has low water availability. < 1 - catastrophically low; 1.1.-2.0 - very low; 2.1-5.0 - low; 5.1-10 - average; 10.1-20 - high; > 20 - very high. Source: Source: World water resources at the beginning of the 21st century” prepared in the framework of ihp unesco
8. Why is recharging so important? While tubewell use is increasing,tank irrigation is declining
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11. Problem villages in drinking water supply Year of Survey Number of Problem Villages identified Number of villages covered till the next survey Number of villages not covered before the next survey 1972 150,000 94,000 56,000 1980 231,000 192,000 39,000 1985 161,722 161,652 70 1994 140,975 110,371 30,604 1997 61,747
19. 5. Potential of water harvesting 4 monsoon months 3000 8 remaining months 1000 Total precipitation 4000 Total river flows - 1953 (75% of this only in rainy season) Percolation into soil 2047 Utilisable - less evaporation, flows to sea & other countries 690 Utilisable - less evaporation, soil moisture 396 Total available for irrigation & other uses precipitation 1086 What is lost – evaporation , soil moisture – which can be captured – 1700 (approx ) Source: National Commission for Integrated Water Resources Development. All figures in Km3
24. 8. Ancient wisdom Dated as far back as 5000 years. Dholavira of the Indus Valley Civilisation was harvesting runoff in the dry Thar desert.
25. 9. Traditional wisdom in the Thar desert A talab is a local reservoir made out of natural depressions on outcrops of hillocks or rocky formations. Usually, only the slope side of the reservoir or talab was provided with strong parapet walls.
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30. 9. Traditional wisdom in the Thar desert The Chittor Fort once housed at least 50,000 people. There were more than 80 water bodies which could hold water that would last the citizens for more than 5 years incase of a siege. Even today, there are 22 water bodies. Udaipur, known all over the world as the City of Lakes, has a network of lakes, which provided the city with drinking and irrigation water and also provided water for its numerous wells and step wells. Today, this water wealth is facing destruction. Water bodies in Chittor Fort Water wealth of Udaipur
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32. 9. Traditional wisdom in the Thar desert The khadin is used even today in agriculture in the Thar Desert. It involves harvesting rainwater in farmlands and consists of an embankment built across a slope in such a way that rainwater is collected within an agricultural field. Virdas was developed by the nomadic Maldhari tribes who inhabit the arid-saline regions of the Rann of Kutch. The maldharis identify the natural depressions ( jheels) from the flow of the monsoon runoff, and then dig small wells (virdas ), within the depression, to collect rainwater. The wells lie over the top of the saline layer, with a transition zone of brackish water between. Bushes and trees, planted on the bunds, protect the virdas .
