Explained | Why DVC water releases spell flood risk for Bengal

Kolkata: West Bengal Chief Minister Mamata Banerjee recently criticised the Damodar Valley Corporation (DVC), a central PSU, for allegedly flooding the southern districts of the state by “unilaterally and wilfully” releasing water from its dams during the Durga Puja festival.

The DVC rejected the charge saying all information about releasing water is shared with the state’s irrigation department but no response comes from officials.

The situation underscores a complex challenge as DVC must release water to ensure safety of its dams, but the downstream river system in West Bengal no longer can handle the entire water volume, leading to inundation in several districts every year.

The DVC's role and current status:

The multipurpose DVC, which operates Maithon, Panchet, Tilaiya, and Konar reservoirs across Jharkhand and West Bengal, is designed for flood moderation, irrigation, and power generation. The three equal stakeholders are the Union government, West Bengal and Jharkhand state governments.

Current data from the state irrigation department shows Maithon reservoir at 483 feet (against a maximum of 495 ft) and Panchet at 415 feet (against a maximum of 435 ft). While these levels are within safe limits, consistent inflows and heavy rainfall have compelled the DVC to initiate water discharges to create storage space and maintain structural safety.

No safe discharge in a silted system:

West Bengal Irrigation Minister Manas Bhunia said there is no universal "safe level" for DVC’s discharges. “It all depends upon the amount of water released by DVC and the present state of the riverbed,” Bhunia told PTI.

According to DVC, in a pre-monsoon meeting with the Bengal government, the PSU has stated that their channels were capable of handling 1.5 lakh cusecs. But, this is in total and including downstream rainfall water volume.

This highlights the core of the problem. The carrying capacity of downstream rivers like the Damodar, Kapaleswari and Rupnarayan gets severely reduced due to sedimentation, encroachments, and rainfall. DVC officials note that these local factors, beyond their control, are a critical determinant in whether a release causes flooding.

The siltation stalemate:

A major, long-term factor crippling flood resilience is silt accumulation. Silt reduces the storage capacity of the upstream reservoirs and, more critically, chokes the downstream riverbeds, raising their base level and reducing the area through which water can flow.

Efforts to address this have been ineffective. A Trinamool Congress MP in 2022 questioned in Parliament whether the Centre had approved a grant of Rs 130 crore for de-silting DVC dams. The Minister of State for Jal Shakti replied: "As informed by the Damodar Valley Corporation, no grant has been approved for desiltation / dredging of DVC dams."

The reply also highlighted that a past DVC proposal to de-silt the Panchet Reservoir in 2012 was dropped due to non-viability and high cost. Furthermore, the Damodar Valley Reservoir Regulation Committee (DVRRC), which oversees dam operations, has confirmed that increasing water holding capacity does not fall under its purview, leaving the critical issue of siltation without a clear responsible agency or financial commitment for a comprehensive solution.

Ground Zero:

The consequence of this is several southern Bengal districts are experiencing significant inundation.

Paschim Medinipur’s Ghatal block, a topographically low-lying and perennial flood-prone area, has been inundated six times this year alone, according to Minister Bhuiyan.

Other affected areas include low-lying parts of Purba Medinipur, Hooghly, and North 24 Parganas and Howrah.

Rivers such as the Kapaleswari, Rupnarayan, Kalighi, and Jamuna have flowed above their danger levels, with overflow ranging from 0.07 to 0.39 metres. Notably, this flooding occurs even as main Damodar gauge stations like Jamalpur and Rondia remain just below their official danger levels, indicating the acute pressure on the smaller, downstream tributaries.

State response and the way forward:

The West Bengal government claimed it has undertaken river desiltation drives, embankment strengthening, and impovoing of channels by creating thousands of ponds to hold rainwater and reduce flooding. In the last June pre-monsoon meeting, the state indicated that their system can handle 1.5 lakh cusec of water flow, DVC officials said.

Chief Minister Mamata Banerjee has repeatedly urged the DVC and the Kolkata Port Trust to assist in maintaining the river systems with proper dredging and desil;tation programs to help prevent worsen flooding situation in Bengal.

Bhuiyan emphasized the need for better coordination with DVC for timely warnings and staged water releases as a solution while DVC claims state officials don't respond. West Bengal officials had tendered resignation from the key positions from the board and DVRRC committee in September 2024.

The recurring floods, especially in vulnerable zones like Ghatal, underscore that the solution lies beyond temporary measures and the state government has approved a master plan after Centre did not respond in support of the Paschim Medinipur town.

The solution necessitates a long-term, coordinated strategy involving massive dredging, sustainable silt management, and modernised reservoir operation protocols to break the annual cycle of flood and damage.