The moment we see silt in a river, our attention shifts from the river to the silt.The assumption seems straightforward: the riverbed has filled up, water can no longer move freely, and removing the sediment will deepen the channel and reduce flooding.
But rivers do not follow such simple arithmetic.
Sediment is not merely a pollutant waiting to be removed. It is part of a river’s natural process. The more important question, therefore, is not whether there is silt, but whether it is accumulating in a way that disrupts the river’s flow, channel morphology or ecological functions.
That distinction matters for Bihar, where debates over the Ganga and its tributaries have repeatedly returned to one question: Should the rivers be dredged?
The more fundamental questions are different: Why is sediment accumulating where it does? How does it move through the river system? And what intervention, if any, can restore the river’s balance without creating new problems elsewhere?
On September 15, 2026, the Bihar Cabinet approved the Bihar Water Resources Restoration and Sediment Management Policy, 2026. The policy proposes removing sediment from rivers, barrages and reservoirs to restore their water-holding and carrying capacities. It also envisages using the extracted material for roads, railways, irrigation, flood protection and construction.
The objectives are understandable. But the success of such a policy cannot be measured simply by the volume of sediment removed.
The real test is what happens to the river afterwards.
Does drainage improve? Does floodwater move more efficiently? Does erosion increase downstream? Does sediment return to the same location after the next monsoon? Are aquatic habitats disturbed?
These questions are not new.
Earlier committees had already cautioned against treating large-scale dredging as a universal solution.
In 2001, a committee headed by former Central Water Commission chairman B.K. Mittal examined the relationship between sediment deposition and flooding. Its conclusions, recorded in government documents, did not regard large-scale sediment removal from major rivers as a routine or economically viable solution. At the same time, it recognised that targeted removal could be considered at specific locations following technical and economic assessment.
In 2016, the Centre constituted the Madhav Chitale Committee to prepare guidelines for sediment management and dredging in the Ganga between Bhimgoda and Farakka. Its approach emphasised the distinct characteristics of different stretches of the river, including sediment transport, deposition, riverbed conditions and the annual sediment budget.
The message from both exercises was broadly similar: there can be no single dredging prescription for an entire river.
The river is more than its riverbed
The government’s earlier efforts also indicate the complexity of the problem.
In 2017, an aerial survey of the Ganga stretch between Buxar and Farakka was undertaken with experts including former CWC chairman A.B. Pandya and specialists from IIT Roorkee. Such exercises recognised that sediment management required detailed technical assessment.
The question now is how much of that accumulated knowledge will inform implementation of the new policy.
The Farakka question, too, needs to be located within this larger scientific framework.
Bihar has for years raised concerns about the impact of the Farakka Barrage on the flow and sediment regime of the Ganga. But attributing the river’s entire sediment problem to a single barrage risks oversimplifying a much more complex system.
River behaviour is shaped by several interacting factors: discharge, channel slope, riverbed morphology, sediment coming from tributaries, bank conditions and human interventions. A barrage can influence these processes, but it cannot by itself explain every change observed along hundreds of kilometres of river.
Bihar’s Himalayan rivers demonstrate this complexity.
The Kosi, Gandak, Bagmati and other rivers carry enormous quantities of sediment from the Himalayas into the plains. Studies by river scientist Prof. Rajiv Sinha of IIT Kanpur have highlighted the close relationship between channel form, flow and sediment.
A riverbed is not a fixed surface, just as a river channel is not a permanent line on a map.
That is why sediment should not be viewed only as material waiting to be removed.
From waste to resource—but with caution
Studies on sustained sediment management in the lower Kosi have also pointed towards the possibility of treating sediment as a resource.
Bihar’s new policy includes provisions for using extracted material. But such use must begin with testing its quality, composition and possible contamination.
A proposal by Sultan Ganj-based poet Sudhir Programmer to use Ganga sediment from the area as filling material for the proposed airport site illustrates the potential for beneficial use.
But the location of the end use cannot, by itself, justify dredging.
The quantity of sediment required, its quality, geotechnical stability, impact on groundwater and drainage, and the consequences for the river from which it is extracted would all require scientific assessment.
Kishore Jaiswal, national convener of the Pragatisheel Krishi Manch, argues for targeted intervention rather than indiscriminate dredging. The first step, he suggests, should be to identify stretches where sediment is genuinely obstructing flow or drainage.
Only then should the required quantity, timing, likely changes in flow and erosion risks be assessed. In sensitive stretches, hydrological and hydraulic modelling should form the basis of decisions.
The participation of river scientists such as Prof. Ramakar Jha of NIT Patna is important in this context.
Rivers cannot be understood merely as visible water channels. Their behaviour emerges from the interaction between water, riverbed, sediment, banks and the wider catchment.
The debate around the National Green Tribunal has sometimes created the impression in Bihar that environmental regulations are standing in the way of sediment removal.
But riverbed dredging for restoration cannot simply be equated with commercial mining.
Large-scale intervention in a river requires technical assessment as well as environmental scrutiny. The relevant question, therefore, is not simply who stopped dredging, but what scientific basis existed—or did not exist—for the proposed intervention.
This caution becomes particularly important in the Bhagalpur region, which includes sensitive habitat for the Gangetic river dolphin.
Changes in depth, flow and sediment conditions can affect aquatic habitats. Flood management, navigation and infrastructure requirements therefore have to be considered alongside ecological needs.
Nor can low water levels be attributed universally to sedimentation.
Deepening a river does not create water.
Water availability depends on rainfall, catchment conditions, groundwater, tributary inflows, wetlands and environmental flows. Sediment removal may improve drainage or flow at specific locations, but it cannot be treated as a permanent cure for water scarcity.
Beyond a dredging programme
This is why Bihar’s new policy should not become merely a dredging programme.
It needs to evolve into a broader river and catchment restoration framework.
That would require river-stretch-wise bathymetric surveys, regular assessment of sediment budgets, modelling under both flood and low-flow conditions, testing of extracted sediment, and safeguards for its subsequent use.
It would also require monitoring what happens after intervention rather than treating dredging as the end of the exercise.
Transparency will be equally important.
People should be able to know where sediment was removed, how much was removed, why the intervention was considered necessary, what study supported it, where the material was taken and what happened during the following monsoon.
Every major intervention undertaken in the name of river management should have a public record of its costs, rationale and outcomes.
For communities living along the Ganga, the river is not simply a channel carrying water.
Suman Saha of Kalyanpur in Munger describes rivers as “the arteries of the Earth”. Her emphasis is on the larger ecological system—riverbank forests, soil, vegetation, biodiversity and aquatic life. She also stresses collective action to prevent plastic, toxic chemicals, industrial waste and domestic garbage from entering rivers.
That broader understanding is precisely what the sediment debate needs.
Cleaning a river is not the same as treating it
A dredging machine can make sediment disappear from one stretch of the river.
What is less visible is whether the intervention alters the river’s equilibrium.
The consequences may emerge only after a flood: a new channel, an eroded bank, a changed riverbed, a shrinking wetland or a disturbed aquatic habitat.
The policy debate in Bihar therefore needs to move beyond the question, “How much sediment should be removed?”
The more useful questions are:
Where does sediment actually obstruct the river? Why is removal necessary there? How much should be removed? What will happen to the sediment after extraction? And what will the river look like after the intervention?
That is the difference between interfering with a river and managing it.
Dredging is relatively easy.
Understanding a river is harder.
The real test of the 2026 policy will not be the number of cubic metres of sediment taken out of rivers. It will be whether, after the next monsoon, floodwater moves more naturally, erosion is contained, aquatic habitats remain protected and the sediment balance of the river has not been disturbed elsewhere.
A river is not saved by fighting its sediment.
It is saved by understanding what that sediment is doing.
Its flow, bed, banks, catchment, forests, wetlands and aquatic life are part of one system.
Bihar’s sediment policy will achieve its larger purpose only when it begins to treat that system as a whole.
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*Senior journalist
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