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The Bamboo-Drip Irrigation System is very popular in Meghalaya.

(i)It is a 200 year old system of tapping stream and spring water by using bamboo pipes.

(ii) Bamboo pipes are used to divert perennial springs on the hill tops to the lower reaches by gravity.

(iii)The channel sections, made of bamboo, divert water to the plant site where it is distributed into branches, again made and laid out with different forms of bamboo pipes. The flow of water into the pipes is controlled by manipulating the pipe positions.

(iv)If the pipes pass a road, they are taken high above the land.

(v)Reduced channel sections and diversion units are used at the last stage of water application. The last channel section enables water to be dropped near the roots of the plant.

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Post-independent India witnessed intensive industrialisation and urbanisation.

(i)This ever increasing number of industries has made matters worse by exerting pressure on existing freshwater resources.

(ii)Industries, apart from being heavy users of water, also require power to run them.

(iii)Moreover, multiplying urban centres with large and dense populations and urban lifestyles have not only added to water and energy requirements but have further aggravated the problem.

(iv)As the housing societies or colonies in the cities have their own groundwater pumping devices to meet their water needs.

(v)Not surprisingly, the fragile water resources are being over - exploited and have caused their depletion in several of these cities.

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The reasons for objections:

(i)The dams that were constructed to control floods have triggered floods due to sedimentation in the reservoir.

(i)The big dams have mostly been unsuccessful in controlling floods at the time of excessive rainfall.

(ii) The floods have not only devastated life and property but have also caused extremely soil erosion.

(iii) Sedimentation also meant that the flood plains were deprived of silt, a natural fertiliser, further adding on to the problem of land degradation.

(iv) It was also observed that the multipurpose projects or big dams induced earthquakes,  caused water borne diseases and pests and pollution resulting from excessive use of water.

Tips: -

V. Imp.

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The significance of Tankas in Rajasthan:

(i)In the semi-arid and arid regions of Rajasthan, particularly in Bikaner, Phalodi and Barmer, almost all the houses traditionally had underground tanks or tankas for storing drinking water.

(ii)The tanks could be as large as a big room; one household in Phalodi had a tank that was 6.1 metres deep, 4.27 metres long and 2.44 metres wide.

(iii)The tankas were part of the well-developed rooftop rainwater harvesting system and were built inside the main house or the courtyard. They were connected to the sloping roofs of the houses through a pipe. Rain falling on the rooftops would travel down the pipe and was stored in these underground ‘tankas’.

(iv)The first spell of rain was usually not collected as this would clean the roofs and the pipes. The rainwater from the subsequent showers was then collected.

(v)The rainwater can be stored in the tankas till the next rainfall making it an extremely reliable source of drinking water when all other sources are dried up, particularly in the summers.

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Hydraulic Structures in Ancient India:

(i)In the first century B.C., Sringaverapura near Allahabad had sophisticated water harvesting system channelling the flood water of the river Ganga.

(ii)During the time of Chandragupta Maurya, dams, lakes and irrigation systems were extensively built.

(iii)Evidences of sophisticated irrigation works have also been found in Kalinga, (Odisha), Nagarjunakonda (Andhra Pradesh), Bennur (Karnataka), Kolhapur (Maharashtra), etc.

(iv)In the 11th Century, Bhopal Lake, one of the largest artificial lakes of its time was built.

(v)In the 14th Century, the tank in Hauz Khas, Delhi was constructed by Iltutmish for supplying water to Siri Fort area.