Diverting Brahmaputra’s Main Channel only long-term solution to save Dibrugarh: Prof. Jogendra Nath Sarma

Amid recurring floods and severe riverbank erosion during the monsoon, noted river expert and retired Professor of Applied Geology at Dibrugarh University, Prof. Jogendra Nath Sarma has stressed that diverting the Brahmaputra’s main channel through scientific river management is the only sustainable solution to safeguard Dibrugarh from the growing threat of erosion.

Prof Sarma, a leading authority on the Brahmaputra’s fluviomorphology has spent years studying bank erosion and channel migration along the river.

Sarma explained how the river’s behaviour near Dibrugarh has changed dramatically over the past several years.

“There was no erosion in Dibrugarh five to six years ago,” Sarma said, recalling that the brunt of the river’s force was then being absorbed by heavy erosion at Rohmoria, on the south bank around 25 km from Dibrugarh. According to him, the Brahmaputra’s channel used to strike the bank at Rohmoria before swinging north-west toward the river’s north bank, sparing Dibrugarh from damage.

That pattern broke down from 2022 onward. “The channel gradually changed its direction and flowed towards Dibrugarh on the south bank,” he said noting that the older channel running toward the north bank (Dhemaji side) silted up and effectively closed by 2023. With the north-bank channel gone, the flow toward Dibrugarh grew stronger and more powerful, triggering erosion at Koilaghat, Joggers Park, Mohanaghat, Aithan and Nagakhelia.

Prof. Jogendra Nath Sarma (Photo by Manoj Pandey)

Sarma warned that temporary measures such as geo-bags and RCC porcupines “may provide short-term protection but cannot permanently address the problem.” He called instead for a comprehensive science-based strategy centred on restoring the river’s old channel, dredging, and controlled diversion of its flow.

“If the present course of the river remains unchanged, Dibrugarh’s embankments and riverside areas will continue to face increasing pressure, posing a serious threat to the city’s long-term existence,” he cautioned.

Photo by Rajib Dutta

As a remedy, Sarma proposed dredging the Brahmaputra at Maijan or Mothola between Dibrugarh and Rohmoria, to scientifically restore the abandoned channel – a move he said would naturally reduce the volume and force of water pushing toward Dibrugarh.

He also flagged rapid silt deposition near the southern end of the Bogibeel Bridge, warning that the build-up is altering the river’s course and could worsen erosion in nearby areas in the future.

On another front, Sarma urged the government to immediately regulate or halt uncontrolled sand and silt mining from mid-river sandbars or chaporis, saying the practice “disturbs the river’s natural balance, accelerates water velocity and aggravates erosion.”

Photo by Rajib Dutta

While appreciating the Water Resources Department’s ongoing efforts, he reiterated that geo-bags and porcupines should be treated only as emergency measures, not permanent fixes.

Sarma appealed to both the Central and State governments to draw up a long-term scientific river management plan for the Brahmaputra, combining channel restoration, dredging, and flow regulation.

He expressed confidence that timely, science-driven intervention could significantly curb erosion and secure Dibrugarh’s future against the river’s shifting course.

Rajib Dutta

Rajib Dutta is a freelance journalist based in Dibrugarh with 25 years of experience in the field of journalism. He can be reached at [email protected]