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Wednesday, September 16, 2009

Rain water harvesting in the North-eastern India-with special reference to Mizoram

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Mizoram is one of the smallest states in the north-eastern India having an area of only 21,000 sq. Km. It is located in the extreme North East of India bordering Myanmar and Bangladesh. The state is entirely mountainous covered with lush green vegetation. The mountains range in a North - South direction and the rivers flow in either a North or South direction. The highest peak namely Blue Mountain is only 7100 feet high and the climate of Mizoram is moderate. Towns and villages in Mizoram are mostly located on hilltops or on the upper reaches of the hills. Since perennial streams and rivers are located much below the habitations, scarcity of water in the dry season is very common. The whole state enjoys abundant monsoon rainfall during the rainy season extending five or six months in a year.

Springs on the hill slope and valleys are the main water supply sources in the villages. In the dry period the yield from springs gets reduced drastically. During the worst dry periods one has to wait long hours to obtain just a bucketful of water from the spring sources. Spring water supplemented by rainwater harvesting still remains today, the main means of water supply in many villages and outskirts of towns.

Through their skill and experience, the people living in hills and mountains of North-eastern India have developed a number of novel practices of farming, checking soil erosion, preventing landslides, and yes – of conserving water. Cropping in terraces along hill slopes is an age-old practice developed by tribal people. Tribals of Mizoram and Nagaland are expert in cutting beautiful terraces along mountain slopes. This system of cropping is beneficial in retaining fertility of soil; preventing land slides and checking soil erosion. Secondly, it is helpful in retaining the moisture of soil and conserving water, also. How are the terraced fields irrigated? Well, here is the answer.

Tribal people in the north-eastern India are expert in cutting beautiful terraces on hill slopes

The terraced fields are irrigated by a network of water- channels of bamboos that reach to every field. The terraces are graduated in so nice and scientific ways that water flows conveniently through the bamboo channels and irrigates the crop fields. Sometimes holes are made in the bamboo-pipes that facilitate the flow of water in drips. Thus the water is saved against any wastage during the process of irrigation. This system of irrigation is called as “Bamboo-drip Irrigation System”.


The Bamboo Drip Irrigation (source- CSE )

The loss of forests and less density of trees in certain regions has altered the pattern of rainfall in some districts of the North –eastern India including Mizoram and Nagaland. The water cycle in these regions has badly been altered and the sources of water have become inefficient. With the skill and experience, the people of these areas have developed a novel method of rain water harvesting and water conservation which is called as Zabo System of Rain water Harvesting.

The word “Zabo” means – impounding of water. The indigenous system of conservation of rain water in Mizoram and Nagaland, through which water is collected and stored in ponds for irrigation and other purposes, is called as the Zabo system of water conservation. The harvesting of water through this system is done by collecting rain water in catchments along mountain slopes. A Pond is dug to store water of the catchment area and all the water flowing down through terraces is facilitated to accumulate into it. The water thus accumulated in ponds is used for various purposes including irrigation. The Government of Mizoram has started a number of projects of water conservation. Rainwater harvesting and spring developments were taken up as a Government Programme. The Rajiv Gandhi National Drinking Water Mission, aiming at providing drinking water to every person, sanctioned a substantial fund for rooftop rainwater harvesting tanks. As many as 198 villages in Mizoram have benefited from the scheme.


Impounding of rain water falling on terraces cut on hill slopes

The Government of Mizoram has started a number of projects of water conservation