This document discusses rainwater harvesting in India. It notes that India has experienced some climate changes in recent decades, including a warming trend along parts of the coast and inland areas and a cooling trend in northwest India. Regional monsoon patterns have also varied, with some areas receiving more rainfall and others less. The document then provides details on rainwater harvesting techniques in India such as collection from rooftops and storage in ponds, tanks, and underground reservoirs. It discusses factors to consider for rainwater harvesting such as collection area, runoff characteristics, and water quality. Design and operational procedures are also outlined.
1. Rain Water Harvesting 12.9.2011 Dr. N. Sai Bhaskar Reddy CEO, GEO http://e-geo.org Centre for Cultural Resources Training (Ministry of Culture, Govt. of India), Hyderabad
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4. Warming trend along the west coast, in central India, the interior peninsula, and northeastern India.
6. Regional monsoon variations: increased monsoon seasonal rainfall along the west coast, northern Andhra Pradesh and North-western India, decreased monsoon seasonal rainfall over eastern Madhya Pradesh, North-eastern India, and parts of Gujarat and Kerala.3
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8. Studies have shown a rising trend in the frequency of heavy rain events and decrease in frequency of moderate events over central India from 1951 to 2000.
9. Records of coastal tide gauges in the north Indian ocean for the last 40 years has revealed an estimated sea level rise between 1.06-1.75 mm per year.
19. RECHARGE WELLS While it would normally take between 20-30 years for water to percolate 100 feet from an open tank, it has been noticed in an open well 300,000 litres can percolate to the same depth within a week. The Barefoot College, Tilonia
22. Geographical area = 329 Mha of which 47% (142 Mha) is cultivated, 23% forested, 7% under non-agri use, 23% waste.
23. Per capita availability of land 50 years ago was 0.9 ha, could be only 0. 14 ha in 2050.uk-energy-saving.com
24. Out of cultivated area, 37% is irrigated which produces 55% food; 63% is rain-fed producing 45% of 200 M t of food. In 50 years (ultimate), proportion could be 50:50 producing 75:25 of 500 M t of required food.
26. What Is Rainwater Harvesting? RWH technology consists of simple systems to collect, convey, and store rainwater. Rainwater capture is accomplished primarily from roof-top, surface runoff, and other surfaces. RWH either captures stored rainwater for direct use (irrigation, production, washing, drinking water, etc.) or is recharged into the local ground water and is call artificial recharge. In many cases, RWH systems are used in conjunction with Aquifer Storage and Recovery (ASR). ASR is the introduction of RWH collected rainwater to the groundwater / aquifer through various structures in excess of what would naturally infiltrate then recovered for use
27. Why Rainwater Harvesting? Conserve and supplement existing water resources Available for capture and storage in most global locations Potentially provide improved quality of water Supply water at one of the lowest costs possible for a supplemental supply source. Capturing and directing storm water (run-off) and beneficially use it Commitment as a corporate citizen - showcasing environmental concerns Public Mandate (India) Replenishing local ground water aquifers where lowering of water tables has occured
28. Why Not RWH? Not applicable in all climate conditions over the world Performance seriously affected by climate fluctuations that sometimes are hard to predict Increasingly sophisticated RWH systems (ASR) necessarily increases complexities in cost, design, operation, maintenance, size and regulatory permitting Collected rainwater can be degraded with the inclusion of storm water runoff Collected water quality might be affected by external factors Collection systems require monitoring and continuous maintenance and improvement to maintain desired water quality characteristics for water end-use Certain areas will have high initial capital cost
29. Condensation Let’s take a look at The Water Cycle Precipitation Evapotranspiration Evaporation Infiltration Surface Runoff Surface Water Consumption Groundwater .ppt (21) Sea water intrusion
31. Collection Area and Characteristics Measure Area Runoff Characteristics Roof top 0.75 – 0.95 Paved area 0.50 – 0.85 Bare ground 0.10 – 0.20 “Green area” 0.05 – 0.10 Water harvesting potential(m3) = Area (m2) X Rainfall (m) X Collection Efficiency
32. Quality Issues Roofs contain: bird droppings, atmospheric dust, industrial and urban air pollution
36. Storage Ponds and Reservoirs Artificial recharge of Groundwater Water Tanks Rainwater runoff in surface water Rainwater runoff in groundwater Rainwater runoff in tanks Effluent in surface water Effluent in ground water Every drop counts
44. Water Conservation Water conservation interventions includes contour trenches, gully plugging, vegetative and field bunding, percolation tanks. Overall land treatment against potential area is varying between 40-60%. Type of land ownership for soil and water conservation measures Techniques of soil and water conservation measures Prof. T. I. Eldho ,