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Anantapur, an arid and backward district in southwestern part of Andhra Pradesh, is often in the news for recurring droughts.
But a first-of-its-kind initiative that maps 103 farm ponds in Bandlapalle village in the district with the help of drones is providing useful insights in the assessment and rejuvenation of water bodies across India.
Scientists of Hyderabad-based National Remote Sensing Centre (NRSC), have used drones to survey, map and calculate the volume of water stored in these ponds and its impact on farmers’ income. These water bodies were built in 2017-18 under the central government’s rural employment scheme, Mahatma Gandhi National Rural Employment Guarantee Act (MGNREGA).
The recent NRSC study has, for the first time, used drones to measure and evaluate effectiveness of MGNREGA farm ponds in the country.
“Our study of 103 farm ponds, which were surveyed using drones fitted with cameras, found that these commons hold 27,810.30 cubic metres of water in Bandlapalle. This water can irrigate 25 hectares of paddy and 62 hectares of groundnut based on the calculations of water requirements for these crops,” Stutee Gupta, a scientist with NRSC, told Down To Earth (DTE) in an exclusive chat.
NRSC is one of the primary centres of Indian Space Research Organisation (ISRO) under Government of India’s Department of Space and is responsible for remote sensing satellite data acquisition and processing, data dissemination, aerial remote sensing and decision support for disaster management.
For enhanced service delivery of various state and central government schemes, NRSC is working closely with various ministries. Since 2016, it is helping in enhanced service delivery of MGNREGA using geospatial tools on the behest of the Ministry of Rural Development. The recent study further measures the impacts of the farm ponds.
Gupta explained how farm ponds were beneficial to farmers. “We calculated the impact of irrigating fields using water from farm ponds and found that it translates into an additional income of Rs 500,600 for paddy and Rs 1,034,880 for groundnut for farmers in the region,” she said.
Irrigating crops through farm ponds is cheaper and eco-friendly as compared to tubewells and deep borewells, which consume a lot of electricity and lead to overexploitation of groundwater, said Gupta. Anantapur is already a water-stressed district with an average annual rainfall of 500 millimetres (mm).
MGNREGA, enacted by the Government of India in 2005, is the world's largest state-implemented labour guarantee (100 days in a year) social protection scheme to build public assets, such as check dams, farm ponds, percolation tanks and other natural resource management works. Every year, lakhs of farm ponds are constructed under this scheme to capture rainwater and runoff for recharging of groundwater and irrigation purposes.
According to the Ministry of Rural Development, more than 1.8 million (1,810,754) farm ponds were built under MGNREGA across the country, between April 2014 and March 2019.
In the past, studies have tried to evaluate the effectiveness of farm ponds, but there hasn’t been any drone-led scientific assessment of the actual depth and water holding capacity of these water commons, which often get silted over a period of time.
Such monitoring is crucial for rejuvenating and reviving farm ponds, particularly for small and marginal farmers (82 per cent of farmers in the country) who practise rainfed farming and farm ponds can benefit them. According to the Department of Agriculture and Farmers’ Welfare, rainfed agriculture occupies about 51 per cent of the country’s net sown area and accounts for nearly 40 per cent of the total food production.
Anantapur in Telugu means blessed with many things. But the reality is far from that, as the district faces recurring droughts and has high out-migration due to lack of livelihood opportunities. Farm ponds are crucial for farmers in this region as they provide irrigation water during crucial periods of farming.
Globally, farm ponds constitute a significant portion of standing water bodies, with over 90 per cent of them covering less than one hectare area. These oases of commons recharge groundwater and reduce the risk of crop failure, making them an integral part of sustainable agricultural practices in water-scarce regions.
Therefore, information about their storage capacity and geometrical characteristics is crucial for management of these commons in the context of climate change. But, due to their small size, hydrographic surveys (which are like underwater X-rays of water bodies) often fail to capture these farm ponds and their impact on a watershed.
Worldwide, drones equipped with high-resolution cameras and sensors have become valuable tools in monitoring farm ponds and provide efficient, precise and cost-effective solutions.
According to Gupta, drones are expensive and can cover up to 10 kilometres with battery limitation and they have to be used judiciously. Scientists at NRSC used both high resolution satellite imagery and drones to carry out this study.
“We got information of all geotagged farm ponds, over 300 of them, in Bandlapalle in Kothacheruvu block. We realised many of them had either dried up or were not holding rainwater,” said Gupta.
“Using a drone, we surveyed and mapped 103 farm ponds. The optical camera fitted on the drone took overlapping photos. We then analysed the data, marked boundaries of farm ponds and calculated the depth of each of these water bodies to arrive at their water holding capacity,” the scientist explained, adding that this was perhaps the first time that any scientific study in the country had calculated the volume of water collected in farm ponds. The total volume of water stored in these ponds amounts to 27,810.30 cubic meters (m³).
“This study and its results are very important as they provide tools and methodology to assess water commons in rural hinterlands of the country and can help draw up a scientific plan for their rejuvenation,” said Gupta.
The Indian government has a Namo Drone Didi scheme under which rural women are trained to operate drones. To promote community stewardship, these women can be further trained to survey and map water commons in rural India, Gupta suggested.
Telangana government has signed a Memorandum of Understanding (MoU) with NRSC in February this year to impart training to operate drones. The training includes familiarisation of regulations specific to the area of operations; basic aerodynamics for fixed-wing, rotary wing; aviation meteorology; and knowledge of ‘No Drones Zones’.
The NRSC team of scientists did not stop at just calculating water holding capacity of farm ponds in Bandlapalle village. They also calculated an increase in farmers’ income due to availability of irrigation water from farm ponds.
Studies show that irrigation can lead to yield increase of up to 39 per cent over rainfed conditions. Taking that into consideration, along with base yield of paddy and groundnut crops, the NRSC team has calculated that availability of water from farm ponds translates to an additional income of Rs 500,600 for paddy and Rs 1,034,880 for groundnut.
This story is supported by the Promise of Commons Media Fellowship 2024, focusing on the significance of commons and its community stewardship.