Why In News?

Assam’s flood situation remains highly critical as the Dhansiri River continues flowing above its danger mark.

About Dhansiri River 

River system

Part of Brahmaputra River System

Origin

Nagaland, near Laisang/Laishiang Peak of the Barail mountain region

Direction

Generally south to north, with changes in course

States

Nagaland and Assam

Length

About 350 km

Confluence

Joins the Brahmaputra near Dhansirimukh, opposite the Majuli region

Important districts

Dimapur area of Nagaland; Karbi Anglong and Golaghat in Assam

Nature

Predominantly rain-fed

Major tributaries

Doyang/Diyung, Diphu, Bhogdoi, Nambar, Doigrung and Kalyani

Tributaries & Drainage Basin

  • Left-Bank Tributaries: Intaki, Diphu, Moradansiri, Kalioni

  • Right-Bank Tributaries: Doyang (Dayang) — the most important and longest tributary, Bara Monglu, Langlong, Khora, Beopani

Ecological Significance

  • Ecological Corridors: The river flows adjacent to wildlife habitats:

    • Intanki National Park (Nagaland)

    • Dhansiri Reserved Forest (Assam)

    • It skirts parts of the Kaziranga National Park ecosystem near its mouth.  

  • Key Biodiversity:

    • The basin holds tropical semi-evergreen and moist deciduous forests rich in commercial timber.

    • It serves as a habitat for endangered aquatic fauna like the Golden Mahseer.

Source: ANINEWS 

PRACTICE QUESTION

Q. With reference to the Dhansiri River, consider the following statements:

  1. It originates from Laisang Peak in Nagaland and is a left-bank tributary of the Brahmaputra.

  2. It flows through Dimapur district in Nagaland before entering Assam's Golaghat district.

Which of the statements given above is/are correct?

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

Answer: (c)

Explanation:

Statement 1 is correct: The Dhansiri River originates from the Laisang Peak in Nagaland. It flows from south to north before merging into the southern bank of the Brahmaputra River. Because the Brahmaputra flows from east to west through Assam, any tributary joining it from the south (left side of its flow direction) is classified as a left-bank tributary.  

Statement 2 is correct: In its initial course, the river cuts through Nagaland and flows directly past the Dimapur district. It subsequently acts as a natural boundary before entering the plains of Assam, where it primarily flows through the Golaghat district until its confluence with the Brahmaputra.