How Asia’s largest oxbow lake is losing its fish, water, and future | HT Ground Report from a Ramsar Site in Bihar

IN Cheriya Bariyarpur, 20 kilometres magnetic north of Bihar’s Begusarai, 40-year-old Naresh Sahni is apprehensively ready and waiting(p) next to Kanwar Lake, Asia’s largest oxbow lake, for visitors.The visitors, who would occupy a tool in Naresh’s boat, are mostly pilgrims to the neighbouring Jai Mangla Garh Temple, which attracts crowds from the neighbouring areas.“A 30-minute ride in ‘bada jheel’ (big lake) for ₹600, and 20-minute ride in the smaller one for ₹200,” Naresh Sahni tells a group who passionately bargain for the trip. This was not supposed to be part of the tourists' original itinerary.“Nobody knew about the lake,” Naresh Sahni told HT. “We would go to the temple, convincing pilgrims to come and take a look at the lake and a boat ride, if possible. We are the ones who have been taking care of this lake,” he added.Naresh Sahni and his family are traditional fishermen who depend on the lake for their livelihood. He has been a frequent visitor to the lake, like his father, since he was 10 years old. Now the family has started doubling down on joyrides as business, as the fish catch has significantly dipped. “Earlier, there were many varieties of fish: puthi (Puntius), garah (snakehead), singhi (stinging catfish), chouri (ribbon fish), rohu. But now only 25% remain. Kawai (Climbing Perch) and desi mangur (Walking Catfish) have disappeared,” he said.Why the lake mattersThe lake, once spread across 63,000 hectares (or 63 sq km), has gradually fragmented into smaller water bodies, as receding water levels expose large stretches of land. The ‘bada jheel' and ‘chhota jheel’ were references to waterbodies that have drifted apart, with the water getting shallower.Kanwar Lake or Kabartal Wetland, declared a Ramsar Site in 2020, was created after the Burhi Gandak river meandered, leaving behind a waterbody that became a lake. An ‘oxbow’ lake is a crescent-shaped waterbody thus formed when the curved channel end up isolated from the main river.The Ramsar tag, conferred under the 1971 Convention on Wetlands signed in Ramsar, Iran, recognises a wetland's international importance — typically for the migratory birds, fish and other species it supports — and commits the government to maintaining its ecological character and “wise use”. India recently reached a landmark figure of 100 Ramsar sites with the designation of the Jai Prakash Narayan Bird Sanctuary (Surha Tal) in Uttar Pradesh on June 5.Bihar's Kanwar Lake has attracted migratory birds but faces an existential threat. It used to have a variety of flora and fauna, including 165 plant species, 394 animal species, 221 bird varieties, plus 53 types of migratory birds. However, the lake area has significantly reduced and so would that number apparently.Also Read | Bihar’s biggest lake left high and dry despite Ramsar tagDecades of disaster ticking in minutesThe lake was declared a protected site by the Bihar government in 1986 under the Wildlife (Protection) Act of 1972, which prohibits any agricultural, industrial or commercial activities.However, the rich biodiversity has pitched the farmers and fishermen against each other, putting the ecology at risk.A 2012 study found that the area of the lake was diminishing rapidly, from 6,786 hectares in 1984 to 6,044 ha by 2004 and 2,032 ha in 2012. Wetland experts say that the oxbow lake is not perennial and depends on a range of factors, like water source and climate indicators. How it can survive“A lake survives through three or four major systems. First is hydrology, second is climate, third is groundwater, and fourth is anthropogenic factors (roads and urban expansion),” Mehebub Sahana, an environmental geographer at the University of Manchester, told HT.“The health of the lake is determined by surface catchments, groundwater and monsoon recharge,” Sahana noted.This lake, however, remains detached from the neighbouring Burhi Gandak river. Plus, a combination of factors — reducing rainfall, human encroachment, climate change and a conflict between two communities — made matters worse.Another issue in the manner of conservation, which the fisherman pointed out was done by a 12-km canal meant to divert the excess water from the lake to the Buri Gandak. “The lake is connected through the channel to Buri Gandak near Bagras. When the lake has abundant water during the ‘Aas’ months (June/July), the water is pulled back from the lake into the river, and it doesn’t allow the water from the river to enter the lake,” Naresh Sahni said.When the government came up with a proposal to build a 4-metre check dam to regulate water flowing through the canal into the river, it was met with protests from the farmers.Also Read | 315 lakes vanished, 203 shrunk in 6 decades: CAGNo map, no delineation, no actionWhile human encroachment, climate change and conflicting interests of the communities steadily shrank the lake over the last two decades, government apathy and lack of policy implementation aggravated the crisis.As of now, there is no government record of land holdings in the area; no demarcation of private land; nor is there any mapping of the sanctuary.Government officials say that without proper mapping and clear demarcation, no project can be carried out.“While the area of the sanctuary is 6,300 hectares, the area under the Ramsar site is 2,620 hectares. Half of that are private land. There are around 4,000 cases of land settlement pending with the district administration since 1989, when the site was notified as a sanctuary by the state government. A case is also going in the Patna High Court,” Abhishek Singh, the district forest officer of Begusarai, told HT. In a recent ruling, the HC stated that 39 families were residing in an unauthorised manner in the Kabartal Bird Sanctuary (Kanwar Lake) and ordered them the district magistrate to relocate and rehabilitate the families at an alternate land.The court also observed that there was no official delineation for the wetland within the Kanwar Lake Sanctuary. The high court is hearing a case regarding the land dispute raised by the farmers too.Also Read | Forest dept completes biodiversity assessment of Najafgarh lakeLast-ditch effort & a five-year planIn the past two decades, the district administration and the state government came up with several plans to conserve the lake, which included a check dam in 2008 to regulate water outflow, demarcation in 2013, and then another attempt at installing a check dam at the canal.However, the efforts yielded little results.The Begusarai Forest Division is also mulling a plan that involves assessment, mapping, and revival of the old drainage linking to the river.“The proposal involves conducting a baseline survey of the lake to demarcate the area from private lands. We are planning an inlet point from the river to recharge the lake and a check dam near Harsain bridge to regulate outflow,” Singh said.Details of the project remain to be finalised.A crucial project was also sanctioned by then chief minister Nitish Kumar in 2024, which was to be executed by the water resources department. Conflicting interest and caste tensionsWhen the district authorities moved ahead with the proposal to install a check gate on the canal to Bagras, conflicting interests between the fishing communities —the Sahnis — and dominant-caste farmers and landowners, including Bhumihars, came to the fore.The farmers argued that the excess water in the lake would submerge their farmland, leaving less land for farming. The depleting groundwater and lack of irrigation have pushed farmers closer to the lake to divert water for farming. Over the years, many have reclaimed land in and around the wetland to expand agricultural activity, often pumping out lake water for irrigation.Whatever remainsThe depleting water levels meant loss of livelihood and less fish catch for the fishermen. “If the embankment (check dam) is built, there will be water in the lake. The land doesn't entirely belong to the farmers, but they have the strength. They don't allow the gate to be built because if the land is under water, then they can't irrigate their land,” Naresh Sahni said, adding, “Fishermen from 16 neighbouring villages are dependent on this lake.”With limited water supply, inadequate rainfall and conflicting interests at play, subject-matter expert Sahana doesn’t rule out the possibility of such oxbow lakes eventually dying out: “Every oxbow lake has a life cycle, and they naturally dry after 100-200 years. Several oxbow lakes which were part of the Ganga have dried over time; the records of which are present in colonial records."Sahana explained further, "The connectivity of water is crucial. A wetland survives because of monsoon recharge and groundwater seepage. If that connectivity is detached, the lake starts drying with time,”