Why is Bihar unable to solve its annual flooding crisis affecting millions?

Millions of people in the state face annual displacement and are forced into makeshift shelters, relying on food dropped by air, and are at heightened risk of water-borne diseases because of floods

Bihar is once again grappling with severe flooding, with 1.18 million people displaced from their homes. Floods have become a perennial problem in the Nitish Kumar-led state as the cycle of destruction unfolds every monsoon, with residents witnessing their crops and livestock wiped out. Many are forced into makeshift shelters, relying on food dropped by air, and are at heightened risk of water-borne diseases.

Despite decades of efforts to find solutions, this flood-prone state grapples with a geographical reality that seems unsolvable at present.

Why is Bihar prone to annual flooding?

Flooding in Bihar is driven by its location downstream from Nepal. Himalayan rivers such as the Kosi, Gandak, Burhi Gandak, Bagmati, and others carry large amounts of sediment due to loose soil in the region. Heavy rainfall causes these rivers to overflow, leading to floods.

As per the state’s Flood Management Improvement Support Centre (FMISC), Bihar is the most flood-prone state in India, with 76 per cent of North Bihar’s population regularly threatened by flood-related devastation.

The Bihar Disaster Management Authority categorises floods into four distinct types:

1. Flash floods: Caused by rainfall in Nepal, with a brief lead time of eight hours and rapid water recession.

2. River floods: Typically caused by overflowing rivers, with a 24-hour lead time and waters that recede over a week or longer.

3. Drainage congestion floods: Occur in river confluences, taking more than 24 hours to develop and often lasting the entire monsoon season (about three months for water to recede).

4. Permanent waterlogging: Affected areas remain waterlogged throughout the year.

The problem of permanent waterlogging arises from silted rivers, blocked drainage channels, and embankment-induced water retention. These are often worsened by local land formations called chaurs, low-lying depressions formed by shifting river courses.

This year, heavy rains in Nepal and water released from the Kosi river barrage triggered the floods. Districts such as Supaul, Darbhanga, Madhubani, and others have been severely impacted.

Problem with embankments: The Kosi dilemma

Bihar’s geography makes flooding nearly inevitable, and for decades, solutions have been sought. Among the state’s most notorious rivers is the Kosi, often referred to as the ‘sorrow of Bihar’.

In the 1950s, embankments were built along the Kosi in an attempt to control its flow. Initially seen as a long-term solution, these embankments failed multiple times, leading to worsened flooding.

This year, the Birpur barrage on the Kosi in Nepal released 6.6 lakh cusecs of water — the highest in nearly 60 years — causing embankment breaches at seven points across four districts, according to The Indian Express. The embankments, designed for 9.5 lakh cusecs, are now overwhelmed due to sediment buildup, leaving about 380 villages and nearly 1.5 million people trapped within the embankment zone. While the government has allocated land for resettlement, more than half of the area remains waterlogged.

Economic impact of Bihar’s floods

While the floods in Bihar don’t always result in significant loss of life, the economic toll is substantial. Damage to crops, livestock, and infrastructure is considerable, and the resulting distress migration exacerbates the state’s economic challenges. The government spends around Rs 1,000 crore annually on flood relief and management.

What are the potential solutions?

For decades, the proposal of building a dam on the Kosi has been discussed, but the involvement of Nepal has stalled progress. Recently, Bihar’s Deputy Chief Minister Samrat Choudhary met with Union Jalshakti Minister CR Patil to propose the construction of an additional barrage on the Kosi. Similar plans are being considered for barrages at Dagmara (Supaul) over the Kosi, Areraj over the Gandak, and another over the Bagmati, The Indian Express reported.

Meanwhile, the Flood Atlas of Bihar recommends a shift in strategy. Instead of relying on structural measures like embankments, it suggests focusing on minimising flood risks and damages, especially for dynamic rivers like the Kosi.

However, the experience with embankments suggests that engineering solutions alone may not be enough to solve the flood problem.