Dhansiri River

Source: NIE

Context: An environmentalist from Assam has raised alarm over alleged hazardous effluent discharge by Numaligarh Refinery Ltd (NRL) into the Dhansiri River, prompting calls for CPCB investigation due to risks to aquatic life.

About Dhansiri River:

• What it is?

• Dhansiri is a perennial river and a major south bank tributary of the Brahmaputra River, flowing through the northeastern states of Nagaland and Assam. It sustains aquatic biodiversity, supports local livelihoods, and shapes forest ecosystems like Dhansiri Reserve Forest and Intanki National Park.

• Dhansiri is a perennial river and a major south bank tributary of the Brahmaputra River, flowing through the northeastern states of Nagaland and Assam.

• It sustains aquatic biodiversity, supports local livelihoods, and shapes forest ecosystems like Dhansiri Reserve Forest and Intanki National Park.

• Origin and Course:

• The river originates from the Laisang Peak in Nagaland at an altitude of ~800 meters above mean sea level. It flows 352 km south to north, finally merging into the Brahmaputra at Dhansirimukh in Assam.

• The river originates from the Laisang Peak in Nagaland at an altitude of ~800 meters above mean sea level.

• It flows 352 km south to north, finally merging into the Brahmaputra at Dhansirimukh in Assam.

• States Flow Through:

• Passes through Chümoukedima and Dimapur districts in Nagaland and Golaghat district in Assam. Forms a natural boundary between Karbi Anglong and Nagaland in parts of its course.

• Passes through Chümoukedima and Dimapur districts in Nagaland and Golaghat district in Assam.

• Forms a natural boundary between Karbi Anglong and Nagaland in parts of its course.

• Length and Catchment Area:

• Total length: 352 km. Catchment area: ~12,584 sq km, making it crucial for the region’s hydrology and agriculture.

• Total length: 352 km.

• Catchment area: ~12,584 sq km, making it crucial for the region’s hydrology and agriculture.

• Major Tributaries: Fed by several important tributaries including: Dayang, Diphupani, Khora, Langlong, and Beopani

• Tributary Of: Brahmaputra River

• Unique Ecological Features:

• High fish diversity: A survey reported 34 species, including mahseer and catfish, vital for local fishery. Supports wetlands (bils) and dense forests—crucial for migratory birds and wildlife corridors.

• High fish diversity: A survey reported 34 species, including mahseer and catfish, vital for local fishery.

• Supports wetlands (bils) and dense forests—crucial for migratory birds and wildlife corridors.