It was revealed by a judicial commission that probed a breach in an embankment along Kosi river that caused the floods in state.
The anti-erosion and flood protection work was done in a shoddy manner and wireless messages were ignored that led to the flood, said report of the one-man inquiry commission headed by Justice Rajesh Walia, retired chief justice of the Patna High Court.
The final report submitted to state government in February was tabled in the state assembly on Friday, six years after the commission was set up.
Inexperienced officers including Satya Narain, the then engineer-in-chief of Birpur, who 'mishandled' the flood protection effort, and the lack of proper communication between the authorities in India and neighbouring Nepal were other causes of the deluge, according to the report.
"Engineer-in-chief, Birpur, failed to provide leadership at the time of crisis. The whole task force at the site in question during the most crucial period of the flood fighting operation appeared to be leaderless between July 31 and August 17. Officers of the flying squad did not have flood fighting experience and there is possibility of their reports being embellished at later stages," the report said.
According to the report, pressure on the spur of the Kusaha embankment from July 31 was not tackled seriously, leading to breach of the eastern efflux bund.
"For two days, flood fighting work was suspended due to firing practice by Royal Nepal Army as well as a fight between locals and labourers," the report said.
The report indicted the water resources department for ignoring the seriousness of the wireless messages sent from the site from July 31 on the rising pressure on the spurs, and doing little to start flood control work on a war footing.
It has also found serious discrepancy in the purchase and use of material like boulders and crates for flood control. The Kusaha embankment near the India-Nepal border on the Kosi river was breached Aug 18, 2008.
Five districts of north Bihar were flooded, killing at least 250 people and rendering nearly three million people homeless. More than 300,000 houses were destroyed and at least 840,000 acres of crops damaged.
The state government appointed the Walia Commission after the opposition said the cause of the breach should be probed. It was asked to examine all aspects related to the efforts to maintain the utility of the Kosi project since its inception in 1953 particularly after a major landslide in 1979 pushed the Kosi towards its eastern bund and a breach in 1991.