#448 2011 · Biplab Ketan Paul / Trupti Jain, Naireeta Services · Agriculture / water management technology
One pipe banks a farm's flood water underground so the same water survives to fight the drought that follows it
the problem
The same land faced both destructive flooding and crippling drought within a single year, and each was treated as a separate, separately expensive problem
background
In parts of rural Gujarat, India, farmland faces two opposite disasters in the same year: monsoon rains waterlog and salinate fields for months, and then a seven-month dry season leaves the same land parched. Standing floodwater dissolves minerals in the soil, leaving a salty crust once it evaporates that prevents future rain from penetrating the ground at all, compounding the damage each year.
The standard response treated the two problems as entirely separate, each needing its own expensive fix: flood-drainage infrastructure to clear the monsoon water away, followed by irrigation systems or well-drilling to supply water during the dry months that followed. Building and maintaining two unrelated systems — one to remove water, another to find more of it a few months later — was a cost most smallholder farmers, particularly women without secure land rights, could never afford.
what everyone would do
The standard approach treated flooding and drought as two unrelated problems on the same land: install drainage infrastructure to clear monsoon floodwater away as fast as possible, then separately fund irrigation systems or drill new wells to supply water once the dry season set in — solving each extreme with its own dedicated, and separately costly, fix.
what they saw
Paul saw that the flood and the drought weren't two separate problems at all — they were the same underlying resource, water, arriving at the wrong time and then disappearing, with the water table sitting empty in between as unused storage capacity. Instead of draining the flood away and then searching for new water months later, the fix was to move the same water from the moment it was a problem to the moment it was desperately needed, using the ground itself as the storage system.
the move
Biplab Ketan Paul, later working with Trupti Jain's Naireeta Services (founded 2011), developed the bhungroo — a filtration pipe that injects excess monsoon floodwater down through the salty surface layer and into the water table below, banking it underground rather than draining it away or letting it evaporate. A single unit can hold roughly 40 million litres. During the dry season that follows, farmers pump the same banked water back up for irrigation, using the flood itself as the source of the water that gets them through the drought.
why it works
Injecting floodwater directly into the aquifer through a filtered pipe accomplishes two things with one action: it removes the waterlogging and surface salinity that ruins the monsoon-season crop, and it deposits that same water underground where evaporation can't reach it, preserving it until the dry season when pumping it back up restores irrigation. Because the fix uses the land's own natural water table as free, already-existing storage, the system needs no separate reservoir, tank, or well-drilling investment to supply the dry-season water — the flood itself becomes the dry season's water supply, so solving the first problem directly funds the solution to the second.
the payoff
A single bhungroo unit serves about five families for at least 25 years, and land that used to be barren or capable of only one crop a year can now support two to three crops annually. The technology won the 2017 Buckminster Fuller Challenge and, through Naireeta Services, has reached farmers across India, Bangladesh, Vietnam and parts of Africa, with tens of thousands of acres brought back into reliable cultivation.
where it breaks
The approach depends on there being a usable aquifer beneath the land capable of holding injected water without it draining away, contaminating a different water source, or being blocked by geology unsuited to filtration and storage — land without that underlying capacity gains nothing from the system. It also depends on the flood and drought genuinely occurring on a predictable annual cycle on the same land; the mechanism has nothing to offer a place where flooding and drought happen in different locations or without the seasonal regularity that lets one phase's surplus reliably become the other phase's supply.
what came after
Bhungroo is now documented by the World Intellectual Property Organization's WIPO Green technology database as a scalable green technology, and Naireeta Services has expanded the model as a women-led social enterprise, using it specifically to give female smallholder farmers, who often lack secure land rights and are hit hardest by climate-driven flood-drought cycles, a route to reliable, multi-season farming income.
references
- [1]Green Technology Book – Tech Story: Bhungroo – Small Technology with Big ImpactWIPO Green, World Intellectual Property Organization, 2023www3.wipo.int
- [2]Saving flood water to get through the droughtsBBC News, 2018bbc.com