Green Nod Granted for Teesta Project Restoration, Work to Begin After 2023 Flash Floods Destruction.

An expert panel from the environment ministry has granted conditional approval for amendments to the green clearance, allowing the resumption of construction on Sikkim’s 1,200 MW Teesta Hydroelectric Project Stage-III. The project, which was severely damaged by flash floods triggered by a glacial lake outburst in October 2023, will now proceed with a redesigned structure.

One of the major changes includes replacing the original 'concrete faced rockfill dam' with a 'concrete gravity dam,' which the project developers, Sikkim Urja Ltd (SUL), believe will offer enhanced resilience and reduce the risk of dam failure due to over-topping.

While granting approval on January 10, the panel imposed a key environmental condition: "All necessary permissions from the Central Electricity Authority (CEA), Central Water Commission (CWC), or any other relevant agency regarding project design and safety parameters must be obtained before construction work begins."

In response to the panel’s concerns raised in a prior meeting regarding the dam's stability, SUL emphasized that, in addition to the redesign, multiple other measures were being taken. These include enhancing the dam’s spillway capacity and implementing an early warning system to better withstand future natural disasters.

The Teesta project, located on the main Teesta River in Mangan district, was commissioned in February 2017 and operated successfully until the flash floods of October 3-4, 2023. The disaster led to the destruction of the dam and flooding of the underground powerhouse, halting its operations. Since much of the underground infrastructure and electro-mechanical equipment can be restored in about 10-12 months, the project developers have sought an amendment in the environmental clearance to expedite the restoration process.

The meeting minutes outlining the clearance noted that four key observations were made by the panel, including the need for a thorough review of the proposed modifications to ensure the dam's structural resilience, given the region's vulnerability to extreme hydrological events.

In response to these observations, SUL confirmed that a comprehensive study had been conducted to identify potential threats from glacial lakes.

ET