Water conservation is the most important need and challenge globally, at present. Though Tamil Nadu has been facing water crisis for the past few years, it has become a historic record this year due to failure of monsoons, incremental heat and eventual drought. There are agencies like NABARD and other NGOs that have been making efforts to tackle this herculean task of conserving water resources by harvesting rain water and increasing the water table of the affected areas. The farmers who have been implementing these techniques of water harvesting and conservation are witnessing the benefits of those efforts.
Mr Vanaraj from Papinayakanpatti, Perayur taluk, Madurai district was able to succeed in cultivating groundnut in his village which has faced severe drought.
“Our village was famous for its paddy cultivation. In those days irrigated agriculture was successfully carried out at the periphery of our village. But it’s happening only during monsoon now. In those lands outside the village which are dry and remaining at the foothill were grown dry land crops like maize, corn and horse gram”, thus continued Vanaraj.
“I was working for a private company in Pondichery. I returned to my village to be with my mother after the sudden demise of my father. I opted to do agriculture and so dug a bore well inside the existing well. But it was in vain. Therefore I started to grow dry land crops such as corn, maize and cotton. Two years ago I was introduced to ‘farm ponds’ by Sakthi Trust. I too have already gathered some information about farm ponds. So, when they assured me that they would arrange for it I agreed to it.
My land is situated nearby the hill. When it rains water will run away across my land. In that land a farm pond was constructed by them, 200 feet away from the existing well. Nature favored me to have rains after the pond was dug and it was filled to the brim.
After a month, I could witness seepage of water into the well which grew in excess to fill the well. Though farm pond got dried up in two months the well was gaining water. With that water I could grow lady’s finger, tomato, cluster bean and onion in two acres of my land. I cultivated them organically without using any chemical fertilizers. I could earn considerably as I maintained the farm properly. Having witnessed my success the neighboring farmers too dug farm ponds. They too had their well filled in. In this severe drought only those farmers who have dug farm ponds were able to grow vegetables in their farm. Even now my well holds water. I have harvested groundnut now. When all greeneries in the village got dried up completely due to drought the reason for my success to do agriculture is because of the farm ponds”. He shared it with utmost confidence.
We spoke to Mr Sakthi Jothi, a poet and Manager of Sakthi Trust to elaborate on the water management methods and techniques to be followed. “The runoff water from the hill passes through the canals of the nearby land and finally enters the river, eventually falling into the ocean. This is the basis of water cycle. Run off that flows from the hill slows down when it reaches the plain. This will facilitate successful agriculture in the plains due to plenty of water. But the rain water at the foothills will run away without being percolated in the soil. In our country there are many hills and mountains but their surroundings and foothills will remain dry due to the same fact.
In those days they used to plough and cultivate the lands often. The common canals, rivulets, ponds, pools and lakes were cleaned and maintained by the people of the nearby villages. But in due course of time farmers opted different jobs and therefore forced to abandon their own lands and eventually not bothered about the common lands of the villages.
The contour from the land at high altitude to lower ranges, as to reach the river, is termed as ‘watershed’. It’s a slope where the water will flow through but never retained. These kinds of lands are aplenty in our country. If these lands are structured scientifically with engineering acumen the runoff can be contained, thereby allowing the flowing water to percolate in to the ground. These kinds of structures have been implemented since 1980s in India.
NABARD has been facilitating to establish nearly 100 watersheds in Tamil Nadu. It not only aspires to increase the groundwater table in these regions but also to support the livelihoods of the farmers living in the neighboring villages.
Though this project has been executed separately by various departments such as agriculture, engineering, rural development and forests, NABARD does it in collaboration with the agriculture department. Towards fulfilling its goal NABARD has chosen 40 agencies as practical demonstrators. Sakthi trust is one among those agencies”. She continued.
“The runoff from the hills are curtailed on the way, slowed down and contained so that it is allowed to percolate the ground. This should be done all along from the foothills till the riverbed where the runoff finally gathers. Then only its benefits can be fully utilized. This is what we did at Papinaikenpatti, Perayur taluk.
Besides developing water resources in the wastelands, we encourage farmers to opt for forest or plantation crops suitable for those lands by providing them those saplings too.
NABARD collectively works with the Watershed Development Agency to execute the project. Through this project, 84% subsidy is given to the farmers towards contour bunding, farmponds and planting of crops. Only 16% needs to be borne by the respective farmers. It can be compensated by their own labor or providing labor charges for the workers”.
Besides, in Ayyampalayam, Dindigul district, with the help of NABARD we have been working on the projects to deal with the agro-climatic changes. Through this program we help the farmers to establish integrated farms, enrichment of well water, azolla culture and fodder grass cultivation. NABARD has been supporting these programs. We could deal with the future of agriculture only when we change each farmland into a rainwater harvesting device”. Thus she concluded.
Rainwater harvesting methods
Various rainwater harvesting methods are described hereunder as shared by Ms Sakthi Jothi.
Rain absorption trench
These canals should begin from the watershed of the hill. Around the foothill, about 1 cubic meter, with one foot gap, pits should be dug in a row. With a considerable gap next line of pits should be dug. The pits between the two rows should be laid in zigzag manner. With a considerable gap a third row should be laid. The soil gained from the pits should be laid opposite to the slope of the hill like a bund. This unit is termed as WAT (Water Absorption Trench) or Water Absorbing Pit.
The speeding runoff from the hill gathers the topsoil from it. The soil will be trapped in the pit and the rainwater will fill those three rows of pits. The eroded soil will fall in the pit while the water overflows the pits. The pits will be filled by rainwater and gets percolated into the ground thereby increasing the water table.
Next to WAT, field bunds can be built based on the terrain of the region. Along the borders of the low lying area of the land, field bund should be built with a width of 1 ½ - 3 feet. These bunds should be built in rows with a meter gap in between. The length of the bund can be 10 to 20 feet.
We can combine field bunds with trenches as well. The soil dug out from the pits can be laid opposite side of the slope so that the runoff water will fill the pits and percolate into the ground, besides protecting the top soil not to be eroded but retained within the pit. It will take 7 to 10 years for the pits to be filled by the eroded soil. These are termed as ‘Trench cum field bunds’.
After laying the bunds it is important to have a farm pond. It is mandatory to have a farm pond in these regions; the size can be smaller or bigger based on the size of the plain. Its depth should be 5 feet but the length and width can be of any size. If the land size is bigger, 2 or 3 farm ponds can also be dug. Fodder crops can be raised along the edges of the farm pond. Kaattamanakku (Jatropa) can be planted along the edges to strengthen the farm ponds. Based on the availability of water one can involve in fish culture too.
Loose rock check dam (LRCD) / Stone wall check dam
The runoff from the hills will flow through the canals and reach lakes, ponds and rivers. While running through the canals the runoff will erode the bunds of the canals. In the eroded areas of the canal bunds, rock stones can be stacked loosely along the damaged bunds to arrest erosion. It is termed as loose rock check dam (LRCD). The runoff will be impeded by these stone walls thereby getting slowed down and gradually flow through the gaps of the stone walls. The small stones and top soil flowing with the runoff water will be contained by the stone walls. These stone walls should be laid only in the narrow regions of the canal.
Gabion or steel grid check dam
Next to LRCD, steel grids can be used to lay Gabion check dams, especially where the width of the canal is broader. As ordinary LRCD will be washed off by the runoff in these areas it is recommended to hold the rock stones using steel nets so that they could withstand the force of runoff waters. This is termed as Gabion check dam as well.
Internal soak pit
Like farm ponds establishing soak pits in these regions are significantly important. In the midst of the canals 3 ½ - 4 feet depth pits should be laid to facilitate deep percolation of rain waters. These pits will hold the runoff and allow it to flow slowly down the canal. Even while the flow of water in the canal gets stopped there will be water available in these pits for some more days. These pits will enrich ground water table and help raise the water levels of the neighboring water bodies.
Along the flow of the canal check dams can be built using cement and concrete in selected parts of the flow route. These check dams stop the flow of runoff water and retain it within the concrete was like a dam. This will help the rising of water levels in the neighboring ponds, lakes, wells and bore wells.
Well water enriching pit
Dig a pit 3 feet away from the existing well, with a dimension of one cubit meter. Erect three cement rings in the pit, one above the other. Fill the pit with pebbles for half a foot. Above it, fill it with bigger stones or blue metals for one foot. Insert a PVC pipe in between these two layers and connect the other end of the pipe to the well. Fill the remaining space of the pit with sand. The rain water flowing through the pit gets filtered and then reaches the well while increasing the water table of the area as well.
Projects for dry regions
We spoke to Mr Nagarajan, Assistant General Manager, NABARD about the Watershed Development program. “This project is executed from the cliff to the valley of the hilly regions. This is a wonderful project that helps in developing fertile lands. Through this program the top soil is protected without being eroded. Simultaneously the rain water also gets harvested. There are 11 such projects being implemented in the southern regions of Tamil Nadu. By virtue of this program the water table has been significantly enhanced in many parts of the region.
Dry and waste lands come to life through these programs. Based on the nature of the regions, various water harvesting methods have been adopted such as water absorption trenches, check dams and farm ponds. Through NGOs these programs are implemented by NABARD. In the select project areas farmers and public are gathered as a team and the program is implemented with the support of the team. Therefore the program is implemented in a most democratic manner as it is designed and executed as a participatory program. The program is heartily welcomed and appreciated by the local beneficiaries as it helps develop water resources in the dry regions and at the same time it also provides right kind of saplings suitable for the region along with the technological recommendations thereby directly supporting the livelihood of the farming communities in the region”.
(This article written by R Kumaresan in Tamil for Pasumai Vikatan 10th August 2017 magazine has been reproduced in English by V Amalan Stanley)