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6.Water Conservation and Demand Management

Author(s): 6.3. Water reuse and conservations technologies
IWRA World Water Congress 2008 Montpellier France
6. Water Conservation and Demand Management
Author(s): Manisha Deb Sarkar
Dr. Manisha Deb Sarkar Reader Department of Geography Women’s Christian College 6, Greek Church Row Kolkata – 700 026 West Bengal, India e-mail : manisha_ds@yahoo.co.in

Keyword(s): flood control, winter crop, floodwater harvesting, indigenous method, low cost technology,

AbstractAbstract:- Application of indigenous floodwater harvesting method of Ajoy River in Raipur village : A micro-level anthro-hydro-geomorphological corollary Dr. Manisha Deb Sarkar Reader Department of Geography Women’s Christian College 6, Greek Church Row Kolkata – 700 026 West Bengal, India e-mail : manisha_ds@yahoo.co.in In the agriculture- based economy of tropical monsoon India availability of water is a vital criterion for its prosperity which in turn is dependent on its production quantity and quality. As the monsoon rain in India varies spatially so also the agricultural methods and cropping patterns. Apart from monsoon water, in India, from time immemorial, the ‘hoe-culture’ had always preferred riverbank sites mainly because of the fertility factor and obviously for the water procured from the river. The fertility, as we all know, is created through ages from the deposition of silt in the playground (flood plain) of the river itself. Silt, when deposited over the extended land sloping down the river from the stagnant spill out at the time of heavy monsoon downpour, enriches the soil. But in village India the people prefer to inhabit in closer proximity to the river to use its water for multifarious purposes. As the seasonal rain diminishes in the post-monsoon and pre-monsoon periods paucity of water in the agricultural sector becomes prominent. At many places, to combat with the situation, from the government level large and small dams across the channels create well sprawl-out water reservoirs, inundating large tracts of land, turn out to be the obvious solution. Barrages supplying water to far and away places through irrigation canals no doubt satisfy the requirement to some extent. But how far all these huge capital intensive and resource exploitative measures are affordable for the developing countries like India raise a million dollar question about their feasibility and a bunch of disputes amongst planners, scientists, environmentalists and acceptability amongst common people. At this juncture low capital intensive, people oriented, people developed and people maintained indigenous method seems to be the judicious solution. Though dependent on environment specific micro-level planning yet in any similar kind of flood prone river adjoined land this well practiced fruitful indigenous method can be effectively applied. Basically Ajoy River being originated from Chhotanagpur plateau region is rain-fed. The river reaches its regime only in the monsoon months from rainwater. The river flows eroding down its granitic forest covered terrain along a narrow course until it initiates to deposit alluvium in its lower reaches where settlements begins to encroach its fertile playground. Anthropogenic intervention, in the form tree cutting, in its upper reach has caused loose binding soil to flow down and spread out in its lower reach resulting in uplevelling of the riverbed and blockage in the midst and on its alternate banks. As the carrying capacity of water lowers down the chances of water spilling consequently increases day by day. Flood now becomes a yearly affair. Its full rage and devastation capacity was fully realised in the year 2000 when floodwater penetrated deep inside at places causing severe damage not only to crops but also to human habitation. Several acres of fertile land are still lying under few feet deep sand deposit. Raipur village is located on the left of bank of Ajoy River and is only 8 kms. south-west from Santiniketan in Birbhum District in West Bengal (India). It has a population of 2063 persons where 1094 are Male and 969 are Female (Census of India, 2001) and most of the working people are agricultural labourers (36.4%; 31% Male and 51.2% Female). Going through the cadastral map of the village it has been found that there is a spectacular shifting of settlements from the river to its opposite direction. These settlements were primarily located on the higher ground within the guard wall of the earthen embankment being constructed mostly parallel to the river by villagers themselves. The embankment was first constructed in the year 1965 / 66 and the primary objective of this is to guard the village from flood invasions. Though Sir William Wilcox, the British personnel from East India Company in 1927, called these earthen embankments (preventive measure to restrict flood water flow) as ‘satanic chains’ which according to him have ruined the natural drainage and irrigation system in the country. However Raipur village fortunately did not too much experience the flood frequency. At present the river is found to be flowing far away from this earthen construction and a long stretch of land with sandy loamy soil formed out of the river overflow lies in-between the two. Dilapidated relics and remnants of the previous settlements are still standing upright at places. The cultivated land area simultaneously also had stretched out offering provision for typical soil oriented and season controlled crop types. The spilt water from the river when invades contains mingled up soil in it which settles down on the ground when the water stagnates for a couple of days. The land enriches but the crop damages. On the contrary, in the dry season, dearth of water hampers cultivation of crops. This two-fold role of water in the two different seasons has prompted the villagers to combat the situation by floodwater harvesting. Floodwater harvesting system enabled the people not only to use the water for cultivation during the monsoon rainy season but also to keep a good storage to be utilized in the dry period. With this practice Raipur is at present harvesting both ‘Kharif’ (summer crop) and ‘Rabi’ (winter crop) crop without wasting the ‘excess’ water of River Ajoy. As for the methodology of floodwater harvesting the people, understanding the slope of land, have cut out a sinuous creek (locally known as ‘kãndar’) from the river connected upto two big water tanks (Morol Pukur and Dikshit Pukur) located at a distance from the river within the heart of the village. Prior to this endeavour these two large water tanks were excavated by the ‘Sinha’ family who are the village ‘zamindars’ (owner of large tract of land) to satisfy the water requirement of the villagers. In order to increase the capacity to hold the additional river water at the time of flood, the extension and depth of the tank was improved by re-excavation. As a result the excess floodwater from Ajoy River in the rainy season through the kãndar culminates into the ‘pukurs’ that act a natural storage ground. The general slope of the village is towards the river which signifies that normal water flow of the river will never enter the land. Water will enter only when it reaches upto the brim and will naturally enter the kãndar to reach the storage ground. After the rainy season is over the river water recedes but the sluice gates being located at the crossing point of the earthen embankment, prevents the kãndar water from going out of it. Here the sluice gates act as control points over the inland flow of water. In the post rainy season, thus, a farmer with comfortable ease can procure his required amount from the kãndar with help of diesel-pumps directly to the fields. This practice has no doubt enhanced the crop production and variation in Raipur. ‘Rabi’ crops like potato favouring sandy loamy soil near the riverbank is one of the important vegetables of the region. Cabbages, cauliflower, mustard oilseeds and wheat are significant ‘rabi’ crops after paddy as the main crop in the ‘kharif’ season. The only problem they are facing is siltation near the sluice gates and regular monitoring and maintenance is required. With the application of this self-sustainable indigenous low-cost technology, Raipur people have not only overcome the wrath of flood in the monsoon rainy season but also by its judicious use, in the dry post-monsoon period, have turned the non-productive land into smiling carpet of varied crops. _________
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