2 to 8 crore litres of water storage ability
Sujata Devadas, April 10 2020
Kovai Thottam’s east to west sloping topography became a huge concern during monsoons to P R Rangaswamy. “I began cultivating these 10 acres in Mettupalayam in 2004,” says Rangaswamy, a PSG Tech electrical engineer with a Masters in Business Administration. “Because of its topography, this land suffered copious damage during intense rainfalls each year. Torrential rainwater surged into it from 50 acres of adjacent uncultivated area higher up in elevation.”
50 acres uncultivated area next to Kovai Thottam
“700mm average annual rainfall in this region (recorded by Tamil Nadu Water Supply And Drainage Board (TWAD) and the Panchayat) means 1 square metre gets 700 litres in a year,” Rangaswamy explains. “So, an acre (or 4046 sq m) gets 28 lakh litres of water through the year. The 50 acres higher up the slope therefore receives 1400 lakh litres of water annually. Roughly half of it flows into my farm. Some water percolates in the red soil but the run-off water takes the surface soil with it down to the ravine on the west and south side close to my farm.”
Rangaswamy counteracted the erosion by constructing a stone masonry check dam with two slipways along the whole boundary of his farm to brake and impede the rate at which water flows in from higher up the slope. Trenches were dug next to the check dam, followed by1 acre 3 feet deep overflow area. The farm also has a pond with 12 lakh litres capacity. All this helped conserve much of the rain water and mitigated soil erosion. Water harvested in this more orderly way, seeped into the ground water table below. One bore well dug in 2004 irrigated his crops during the dry seasons. It’s abundant water supply was shared to irrigate neighbouring farms too.
An Indian company in the vicinity, Rangaswamy learnt, earned profits at this time by selling high quality jasmine flower concentrate to an Italian company. This jasmine extract was added as the central ingredient of a highly valued perfume. The percentage of flower extract inside the perfume was strictly specified.
Drought caused agricultural havoc in Mettupalayam in 2017. It hit the jasmine crop too. Consequently, the supply of jasmine concentrate to the Italian company fell, affecting the perfume’s high quality. The Italian company’s representatives suggested the use of Corporate Social Responsibility (CSR) funds by their Indian partner to employ the services of Bhungroo® - an innovation promoted by Naireeta Services and its non-profit arm, Sustainable Green Initiatives Forum in Gujarat state - to resolve the adverse impact of drought in the future.
The healthy straw
Bhungroo® team assessed the need. After surveying the jasmine crop area with a ground penetrating radar and a geophysical scanner, it sourced geomagnetic information from a satellite and used ultrasound to pinpoint 2 locations in 2 different areas to build fully automated rainwater storage structures (RWS).
”‘Bhungroo’ means hollow pipe or drinking straw,” says Biplab Ketan Paul who invented this harvesting technique, “We don’t go in search of water. We look for a suitable geophysical place to store water underground and use it for agriculture or other needs. Tailor-made to the geophysical peculiarities of each site, the motive is to help everyone. It costs approximately INR2,00,00,000 to construct a 1 million litres overhead water storage tank. At 1/10 that cost, we aim to store rain water underground. It lasts for 40 years if used sensibly.” So Bhungroo® has 17 different RWS designs. Biplab heads Naireeta Services Private Limited, Bhungroo’s parent organisation.
Biplab Ketan Paul explains the under-construction Bhungroo facility's water storage method to local farmers
Bhungroo’s RWS are in India, Bangladesh, Vietnam, Ghana, Mozambique, Kenya, Uganda and Rwanda. Training has been imparted in these countries to implement RWS units with Bhungroo’s technical guidance. Awards rolled in from 2014 from the Indian Government, twice from United Nations, Cartier and others for finding a global solution.
The outcome of Bhungroo® as explained by M Balu, Chief Geologist of Naireeta Services Pvt Ltd., left Rangaswamy speechless with surprise.
After finishing survey and assessment, on 26th March 2018, Balu sent the geophysical analysis report with a graphical representation of various layers from surface level down to 500 metres under Kovai Thottam. 2 separate empty zones or aquifers with the capacity to hold 4 crore litres of water lay under Rangaswamy’s field.
Graphic representation and report
M Balu, Chief Geologist, Naireeta Services Pvt Ltd.
“The best filtration system for water is Earth. Some of the layers are porous. It was mostly rock under Rangaswamy’s acreage. Water stored in this depth does not evaporate” Balu clarified.Balu has worked for 10 years in World Bank Projects all over Tamil Nadu, 7 years in Odisha at water lift irrigation programmes and with Naireeta Services in Ahmedabad since 2017.
Overjoyed, to fill 2 crore lItres into the empty aquifer nearest to the surface, Rangaswamy promptly dug a 500 feet deep bore well costing INR50,000/-. This bore well is currently not used for any other purpose except to harvest rainwater and fill that empty zone.
“My enthusiasm was understandable,” he says, “because water supply from my first bore well stopped after 8 years; a second one dug in 2006 also ran dry 3 years later. 8 more bore wells, I kept failing to get water. In 2017, the year of the drought, I found books titled ‘Rainwater Harvesting for Drylands and Beyond’ written by Brad Lancaster. Brad’s account of Zephaniah Phiri Maseko, a Zimbabwe national’s predicament, was so similar to mine. Maseko partnered with nature for 40 years to cultivate crops successfully on a land that was a barren hilly terrain earlier.”
Separate from filling the huge empty aquifer, he used knowledge from Brad’s books and some Indian ones to recharge a ground water table by re-designing 2 bore wells. Those irrigate the curry leaf, coconut, sapota, mango, guava crops and 400 assorted wood yielding trees in Kovai Thottam now.
P R Rangaswamy and his thriving crop cultivation
At age 72, this farmer captures rainwater falling on his farmhouse roof and directs rainwater through ducts into a pond. An open well holds rainwater too. Despite all this, some rain water still goes into the adjacent ravine. The 2 crore litre ground water area is a closed space. Except for seepage, Rangaswamy has 80% access.
The next big benefit happened when Balu addressed a gathering of local farmers' from Tamil Nadu and Kerala. While some showed skepticism, VKC footwear company expressed keen interest to try the RWS venture. Their valid reason: VKC was confronting massive outrage from the local community because their Mallumecham Patti factory's use of 3 to 4 bore wells (1500 ft in depth) resulted in other bore wells around the factory running dry.
This time, an 8 km-long empty aquifer passing under VKC’s 17 acres - with 7 or 8 crore litres capacity to hold water - was observed. VKC redesigned a bore well to harvest rainwater and recharge that empty zone.
Like an answer to prayers, 1000 to 1200mm of rain fell in the next two years: 2018, 2019. Around VKC’s water harvesting bore well, In a 2 km radius, water returned to wells and bore wells near Pollachi.
Rangaswamy, an executive member of Organic Farmers Association, gives talks in his native tongue Tamil, on the pivotal importance of rainwater harvesting. His striking point is that Tamil Nadu state capital “Chennai has no water shortage. An urbanite uses 75 litres per day. A nuclear family of four needs 109,500 litres of water (4x75x365) in a year. But with 1550mm average annual rainfall, Chennai gets much more. 1.5 lakh litres of water fall on a 1000 sq ft roof of a house in this city every year. The shortage is fake because rainwater is not harvested from the roof and stored for use.”
“Of course water gets depleted if you use it but do not deposit it. Simply harvest rain water in an existing bore well or in an open well to remove ‘scarcity’.” Rangaswamy points to the lesson that he, VKC footwear company and many others have learnt and practice.
July 21 2017: Shanmugham's barren land in Kumarkundru village, Annur Block near Coimbatore
Shanmugham's land on June 10 2018 after using Bhungroo® RWS. This area received 7 days of rain within these 11 months.