He sought a visit by a team of experts to review the silt deposition in the Ganga river and said a 'Silt Management Policy' should be formulated at the earliest.
Ganga and other major rivers have submerged vast swathes of Bihar over the last few days, forcing thousands to leave their homes. The disaster has so far claimed 14 lives, including nine in Bhojpur district alone.
Talking to reporters after meeting the prime minister, Nitish Kumar said the water retention capacity of Ganga has reduced due to siltation and that was a major reason for floods in the state year-after-year.
"If we don't realise the importance of desilting Ganga now, then the conditions would become worse in the coming years as its water will spread in more new areas," the Bihar Chief Minister said.
"To improve the water retention capacity of the river, silt management is required and the government must think to bring 'Silt Management Policy'," he added.
Kumar also requested Modi to send an experts panel to find a permanent solution to the flood problem.
"I have requested the Prime Minister to send the experts to Bihar to assess the situation," he said, adding, "The Prime Minister has assured of all possible help."
The Janata Dal-United (JD-U) leader said that excessive siltation will also affect the Modi government's Namami Gange project.
Nitish Kumar said heavy rain in the neighbouring states was adding to the problem as contributory rivers bring more water to the Ganga.
"The Indrapuri barrage released around 12 lakh cusec water in river Sone in Bihar and Bansagar barrage also released huge amount of water resulting in unprecedented rise of water level," Nitish Kumar said.
