How migrant farmers turn Bihar’s sand-drowned floodplains into cash crops

 

In the flood-prone Kosi Diyara region of Bihar, water security is often defined not by scarcity, but by the challenges of living with hydrological volatility and seasonal extreme flows. In a field report published on July 28, 2026, by the South Asia Network on Dams, Rivers and People (SANDRP), Dr. Rahul Yaduka, Postdoctoral Researcher with the WATCON Project at SOAS University of London, outlines how seasonal migrant farmers are redefining water security by adapting to the erratic nature of the Kosi River rather than fighting it.

The Kosi Diyara—the active floodplains trapped between embankments along the Kosi River—presents a stark paradox: a quantitatively water-abundant landscape where local residents face persistent seasonal water and crop insecurity. During the Kharif monsoon season from mid-May to mid-October, paddy crops are frequently submerged by floodwaters. Conversely, during the Rabi cultivation window between December and April, local farmers struggle with a lack of capital and irrigation infrastructure, even as water table levels remain high.

​"In Kosi, water insecurity is not about scarcity per se. Rather, it is produced in a thick context where hydrological volatility, weak infrastructure, spatial fragmentation due to embankments, and adaptive responses intersect," explains Dr. Rahul Yaduka.

​When floodwaters recede around late October, they leave behind an unpredictable mosaic of river channels, cultivable land, and thick deposits of sand and silt. If fields are buried in heavy, coarse sand, traditional agriculture becomes impossible for local landowners, often forcing them to migrate for menial labor or work as sharecroppers. However, Dr. Yaduka's fieldwork across Supaul and neighboring districts highlights an innovative seasonal agricultural model led by migrant farmers from the Baghpat district of Western Uttar Pradesh.

​These migrant farmers negotiate five-month leases from December to April with local village heads (Mukhiyas) and landowners for sand-covered lands previously written off as unusable, paying approximately ₹2,400 to ₹3,200 per acre. Entire families relocate to the Diyara, constructing temporary huts out of locally harvested materials. Bringing specialized rear-tractor tools on multi-axle trucks and utilizing thin irrigation piping brought directly from Uttar Pradesh, the farmers dig rows of trenches into the sand.

​To cultivate cash crops such as watermelons, pumpkins, muskmelons, cucumbers, and bottle gourds, farmers protect young saplings using walls made of local grass (Khar) and plastic sheets against harsh winter winds and fog. Sourcing organic manure made of local poultry excreta mixed with small amounts of Diammonium Phosphate (DAP), they draw groundwater from the shallow riverbed table using portable pump sets. The crops become ready for early harvest by April and are predominantly exported to higher-value markets in West Bengal.

​Despite the profitability of sand-bed farming—where investments of ₹6.5 to ₹7 lakh on a 10-acre plot can net profit margins of ₹2.5 to ₹3 lakh in favorable seasons—local Diyara farmers rarely adopt these practices. Through conversations with both local elders and migrant cultivators, Dr. Yaduka identified several structural barriers preventing local adoption. Upfront costs for quality seeds, organic manure, specialized tractor attachments, and piping require capital surpluses that local subsistence farmers lack. Additionally, sand-bed farming requires relentless manual labor under extreme conditions, including drying sand and hot spring winds, contrasting with the less consistent work required for traditional wheat or paddy crops. State agricultural agencies in Bihar have also provided little to no institutional or financial support to train or assist local farmers in adopting sand-bed horticulture.

​Dr. Yaduka concludes that the experience of the Kosi floodplains challenges standard policy definitions of water security. Instead of viewing water security as a static state achieved through permanent infrastructure or flood containment, the practices of migrant farmers demonstrate an adaptive, fluid model.

​"Rather than a single, universal standard, water security means different things depending on who is using water and for what purpose, under what circumstances... The migrant farmers offer a striking counterpoint: their security derives precisely from working with the region's hydrological logic rather than against it," states Dr. Rahul Yaduka. He emphasizes that this form of water security remains inherently provisional, seasonal, landscape-specific, and contingent, demonstrating resilience built on ecological adaptation rather than structural stability.