The rhino was spotted by locals at Rani Chapori of Sualkuchi near here in Kamrup Rural district and was suspected to have strayed from the Pobitora Wildlife Sanctuary near Guwahati and washed downstream by the flooded river Brahmaputra, district administration sources said.
The district administration has provided the rhinoceros with food.
Deputy Commissioner Supriyo Kumar Roy said the helicopter was requisitioned by the district administration for airlifting the pachyderm to either the Pobitora or Kaziranga National Park.
Bad weather, however, delayed the airlift while the tranquiliser gun was awaited.
For its safety, the forest department, police, river police and the DC were guarding the animal since last night against poachers.
Five rhinos have been killed and their horns removed by poachers since September 26 and another five have perished in the floods. This year a total of 18 rhinoceroses have died.