Why in the News
Bihar received 27 per cent below normal rainfall between 1 June and the first week of September, and large parts of the state are still under water. Six rivers, the Ganga, Gandak, Kosi, Budhi Gandak, Punpun and Ghaghra, have risen above danger levels in different stretches. The flooding therefore cannot be explained by how much rain fell on the state, which locates the cause in how its rivers and channels are managed. The state’s inherited answer has been containment, holding rivers inside defined channels behind embankments since colonial times. That method separates a river from its floodplain, and with silt raising the bed year on year it reduces the channel’s capacity to carry the discharge it is given. The contested question is whether flood works should keep aiming to hold the river in, or to give it space to spread safely.
Why did rivers cross danger levels in a deficit monsoon?
- The rainfall record for the season: The state recorded 27 per cent below normal rainfall for the period from 1 June to the first week of September.
- Two causes acting together: High upstream river flows combined with erratic weather, meaning spells of heavy localised rainfall inside an overall seasonal deficit, pushed rivers over their banks.
- A tributary can flood because the main river is high: The unusually high level of the Ganga created a backwater effect in the Gandak and the Punpun, the condition where a high level in the receiving river obstructs the outflow of a river draining into it.
- What that effect did: Both tributaries drain into the Ganga, and its high level made their discharge difficult, so water backed up in the tributaries and added to the flooding.
- Danger level is a gauge based threshold: It is the level fixed for each gauge site above which a river threatens habitation and property, so six rivers crossing it in different stretches describes localised failures rather than one basin wide event.
What does containment by embankment do to a river?
- It cuts the river off from its floodplain: Embankments separate rivers from the floodplains that would otherwise absorb and spread a high discharge.
- The bed rises inside the confined channel: Continuous silt deposition raises the riverbed and reduces the channel’s capacity to carry flow.
- A breach concentrates the damage: When an embankment breaches, artificially contained water rushes into homes and fields at a depth and force an unconfined flood would not produce.
- Each year of containment narrows the next year’s margin: A rising bed inside fixed embankments means the same discharge sits higher against the same defences, so the safety margin shrinks with no change in rainfall.
Why will higher embankments not settle the problem?
- The premise needs revisiting: The state needs to reconsider the idea that higher or stronger embankments will by themselves contain floods, since the containment is what raises the bed against them.
- Maintenance remains an obligation: Existing embankments protect settlements and land that have grown up behind them, so the choice is not between maintaining them and abandoning them.
- The stated objective is the opposite of containment: Persistent monsoon floods point to the need to give the river space to spread safely during periods of high discharge, which a confined channel is designed to prevent.
- This is an execution problem, not a knowledge problem: The measures required are already identified in policy, and the flooding continues, which places the failure in implementation rather than in diagnosis.
What must accompany embankment maintenance?
- Restoration of drainage channels: The natural and constructed drains that carry water off the land have to be reopened, since water that cannot drain stays on fields after the river level falls.
- Protection of floodplains: The land a river needs during high discharge has to be kept free of the construction and occupation that turns a spread into a disaster.
- Better land use planning: Where settlement, cropping and infrastructure are permitted has to follow the flood behaviour of the stretch rather than precede it.
- Restoration of wetlands: Wetlands in the basin hold and release flood water, and their loss transfers that volume to the channel and to the settlements behind the embankment.
- Deployment of early warning systems: Warning converts an unavoidable flood into an evacuated one, and it is the only measure on this list that reduces loss without altering the river.
Why has an existing basin plan not changed the outcome?
- The imperatives are already on record: The Ganga Basin River Management Plan, implemented for more than a decade, acknowledges these requirements.
- The outcome has not followed: Persistent monsoon floods in Bihar show how much remains to be done to give the river room to spread during high discharge.
- One requirement sits outside the state’s control: Addressing Bihar’s concerns requires greater coordination between the riverine states on reservoir releases, since a downstream state’s peak is partly set by upstream release decisions.
Where does the Farakka question sit in this argument?
- The state’s long standing contention: Bihar has argued that the barrage and the India-Bangladesh Ganga water sharing treaty compounded its river management challenges.
- The mechanism it alleges: Its case is that the barrage altered the Ganga’s flow regime, affecting the movement and deposition of the river’s sediment load.
- The causal claim is not settled: The extent to which this contributes to flooding in Bihar remains contested, so it cannot carry the whole explanation for the season’s flooding.
- The claim still belongs in the negotiation: Renegotiation of the 1996 treaty, which expires in December, should take account of Bihar’s concerns over silt accumulation and the state’s river management needs.
- The evidence base has to be current: Any new arrangement needs to be informed by updated data on river flows and climate change projections rather than on historical records alone.
- The principle extends past this treaty: In a period of erratic weather, states and countries sharing a river basin have to strengthen coordination to manage flows and reduce flood related distress.
Challenges to embankment based flood control in Bihar
- The network is too long to maintain to standard: Bihar carries roughly 3,800 km of flood embankments, and every weak section of it is tested in the same few weeks each year. Eg. Breaches are recorded each season at several points across different river systems rather than at one predictable location.
The Fix: Publish a stretch wise condition rating for the full embankment length before each monsoon, with repair funds released against the ratings rather than spread evenly. - Containment creates waterlogging behind the line: An embankment that keeps a river out also keeps rainwater and local drainage in, so land behind it is lost to standing water rather than to flooding. Eg. Large areas in the Kosi and Gandak belts of north Bihar remain waterlogged well after river levels have fallen.
The Fix: Build and maintain sluice and pump drainage at every point where an embankment crosses a natural drain, and treat the outfall as part of the embankment asset. - People live between the embankments: Villages inside the embanked corridor are flooded every year by design, without the protection the structure was built to provide. Eg. Settlements between the eastern and western Kosi embankments are inundated annually while the land outside them is defended.
The Fix: Fix a statutory resettlement and compensation entitlement for households inside the embanked corridor, separate from general flood relief. - The decisive failure point can lie outside the state: The Kosi and the Gandak are regulated by structures in Nepalese territory, so a breach beyond Bihar’s jurisdiction can determine its flood year. Eg. The 2008 Kosi flood followed a breach at Kusaha, upstream of the barrage in Nepal, and displaced close to three million people in Bihar.
The Fix: Establish a joint pre monsoon inspection and certification regime with Nepal for the Kosi and Gandak structures, with agreed repair timelines. - Warning lead time is short because the catchment is foreign: Rainfall and discharge data from the upper catchments decide how much notice a district can be given, and that data is not generated within India. Eg. A peak on the Kosi can reach the Bihar plains within a day of heavy rainfall in its Nepalese catchment.
The Fix: Extend real time telemetry sharing across the upper catchments and route it directly to district administrations rather than only to state control rooms. - Silt removal has no funded programme: Reversing a raised bed is slow work with no annual budget head behind it, so the only measure reliably funded is raising the embankment. Eg. Dredging in the state is undertaken for navigation on specific stretches rather than for restoring channel capacity across a river.
The Fix: Create a standing sediment management head in the state’s water resources budget, reporting channel capacity rather than embankment height as its outcome.
Conclusion
A flood season inside a rainfall deficit places the cause in the river system rather than in the monsoon, and that changes what a flood programme should be measured against. Protection built on confining rivers cannot hold once the beds inside those confinements keep rising. The question Bihar now faces is whether it makes channel capacity and floodplain space the stated objective of its flood works, or continues to judge success by the height and length of its defences. The water negotiation ahead is where the state’s sediment case will either become an operating rule or remain a grievance.
Back2Basics: Ganga Basin River Management Plan
- What it is: A basin scale plan that treats the Ganga as a single hydrological unit, covering environmental flows and sediment alongside pollution abatement, rather than as a set of separate state level works.
- Why a basin frame: The Ganga basin covers about 861,000 sq km in India, close to 26 per cent of the country’s geographical area, spread across 11 states.
- Who carries the Ganga programme: The National Mission for Clean Ganga, under the Ministry of Jal Shakti, is the implementing arm of the National Ganga Council and was constituted as an authority under the Environment (Protection) Act, 1986.
- What a basin plan can and cannot do: It sets requirements across the basin and depends on state departments and inter state coordination to execute them, which is how its imperatives can stand on record for years without changing outcomes on the ground.
Matching Previous Year Question
“[2017, GS1, 15 marks] In what way can floods be converted into a sustainable source of irrigation and all – weather inland navigation in India?”
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