Patna: The Narendra Modi government's plan of transforming rivers into waterways is impractical and dangerous for the environment, an expert said here on Wednesday.

Shripad Dharmadhikary, the founder of Manthan Adhyayan Kendra, a Pune-based centre to research, monitor and analyse water and energy issues, tore into the Centre's narrative of cheaper and environmentally sustainable commercial transport.

"Converting the state's rivers into national waterways would change their natural course while dredging can threaten aquatic animals and inland vessels will add to water pollution," he said during the release of a report on "National waterways in Bihar: A description". "It may also cause a decline in the number of fish, severely affecting the livelihood of fishermen."

He added: "Large-scale dredging activity is required to overcome the silt problem at a huge cost. So it will not be able to provide cheaper transport of goods."

Shripad said in case of the National Waterway 1 - stretching from Allahabad in Uttar Pradesh to Haldia in Bengal, passing through Bihar and Jharkhand - increase in the route distance will increase the cost of shipping companies. On river, the distance is 1,620km while on land it is roughly 1,000km, he said.

Chief minister Nitish Kumar had also said on June 25: "If the silt issue is not addressed, the waterways scheme will not be successful."

Shripad, a IIT-Bombay graduate, runs the research centre in Pune.