Survey on water levels, sediment flow in Teesta to be held

Jalpaiguri: The waters of four rivers — Leesh, Ghis, Juranti and Nandikhola — merge into the Teesta, along with water from the Sikkim, creating fluctuating water levels and impacting flood-prone areas.

To better understand this interaction, the River Research Institute and the State Irrigation Department are set to conduct an in-depth hydrological survey by the end of November.

This survey will analyse the water volume and sedimentary content, including sand, silt, gravel, stones and organic debris, released from the Teesta Barrage at Gajoldoba into the Teesta River.

The Supervisory Control and Data Acquisition (SCADA) system, used at the Teesta Barrage to measure and release water levels automatically, will be crucial to this survey.

Currently, water levels are managed manually and during heavy rainfall, the release from the barrage is controlled to prevent flooding.

However, even regulated releases have caused unexpected water level rises in the Teesta, as additional waters from the Leesh, Ghis, Juranti and Nandikhola rivers contribute to the flow.

Warnings are typically issued when specific volumes, measured in cubic meters per second (cumecs), are released from the barrage.

However, recent floods in June, July and August affected unprotected areas in regions like Rajganj, Malbazar, Kranti, Maynaguri and Mekhliganj despite only moderate water releases.

These incidents suggest that even small releases can inundate low-lying areas, making the need for precise measurement and planning more pressing. The survey will involve experts from the River Research Institute and other specialised organisations.

Together, they will calculate the inflow and outflow of water and quantify the sediment carried by these rivers, addressing the composition and quantity of materials such as tree trunks, sand and stones.

Krishnendu Bhowmik, Chief Engineer of the North-East Division of the Irrigation Department, explained: “The Teesta Barrage Authority oversees this matter. With the additional inflows from rivers like the Leesh and Ghis, Teesta’s water level rises significantly. Once the Institute completes its observations, further planning will follow based on state directives.”