Floating solar pumps help Tamil Nadu farmers fight groundwater salinity
A 20 kWp solar water pumping system with floating panels has been commissioned at Dharmakulam in Vishnupuram village, Tiruvarur district, under an initiative supported by alumni of the Indian Institute of Technology, Madras. The system, drawing entirely on the pond's water, can irrigate about 20 acres of farmland without relying on borewells or grid electricity.
The initiative is led by the Societal Impact Action Group (SIAG) of the IIT Madras Alumni Association and funded by WHEELS Global Foundation. The group works on a 'seed multiplier capital' model — one-time philanthropic funding builds the assets, while recurring savings from reduced energy and maintenance costs finance replication in the next village. Vishnupuram is the first of five model villages SIAG aims to establish by 2030.
The system was installed and commissioned by Bengaluru-based PlaySolar Systems Pvt. Ltd. It was inaugurated recently by R. Vinoth, Minister for Agriculture and Farmers Welfare, in the presence of V. Kamakoti, Director of IIT Madras.
“The floating system cuts evaporation from the pond, and the panels actually perform better over water,” said Mukundan Narasimhan, Founder and Director of PlaySolar Systems. The entire system can be monitored remotely, he added.
The pond is fed by the Arasalar river, and the solar pumping system will be used to irrigate fields once water is released from the Mettur reservoir. Project planners say they do not want to deplete the pond's current storage.
Vishnupuram lies in the Cauvery delta, where years of overexploitation of groundwater have gradually turned the region's aquifers saline. If the model is replicated — using solar-powered surface water instead of tapping groundwater — the increasing salinity in the delta can be checked, according to the project's planners.
A few hundred metres away, at the Amruteshwari Go-Seva and Research Foundation goshala, a plant commissioned in March this year produces 2,000 litres a day of natural liquid fertiliser from cow dung and urine, along with bio-gas that supplies free cooking fuel to 10 village households. The first 100 farmers received the fertiliser free at the inauguration. By using the liquid fertiliser, farmers can cut input costs by more than half, and yields can increase by 20–25% as soil fertility recovers season on season.
“Our cows now sustain the village twice over,” said V. Padmanabhan, Honorary Chief Executive Officer of the Foundation. “Their dung and urine become valuable natural fertiliser, and the goshala stands on its own without depending on milk alone. Farmers spend less, harvest more, and the soil grows richer every year,” he said.
These twin initiatives — floating solar irrigation and natural fertiliser production — offer a replicable model for sustainable agriculture in the Cauvery delta, addressing both water scarcity and soil degradation while reducing dependence on groundwater and chemical inputs.
