Key Stakeholders

NHPC, Sikkim

Clients Problem(Background)

A severe nonstop rainfall triggered a massive landslide Dikchu area in the Teesta-V Power Station region. After more than 48 hours of rain, the situation went to worsen. According to the report at 7.30 pm on June 27, 2020, said: “A massive landslide caused severe damage to a dam of the NHPC Teesta Stage-V project site at Apdara in East Sikkim”, as PTI & Central Water Commission’s Flood Forecasting said.

It was a massive avalanche with rocks land sliding that was sitting on top of the dam. This incident took place on the left abutment hillside of the Dam Axis. It fell from a height of about 40 meters from the Dam top. This incident, severely damaged the 55-meter high dam of the 510 MW Hydropower Project of National Hydroelectric Power Corporation (NHPC), possibly in the late hours of June 26, 2020, or early hours of June 27, 2020.

Due to this slide, the access to Dam Control Room (DCR) along with the electrical connection to the Dam top was isolated. The local life in Aapdara village was at stake as NHPC Stage-V Dam lies 90 degrees below Aapdara village which is the inhabitation of 27 families. Lum & Lingtyang village of Lower Dzongu of North Sikkim was isolated from the rest of the district due to this massive landslide. All these areas of North Sikkim become inaccessible for vehicles due to this gigantic rock fall.

Clients Problem(Objective)

• Make a plan for salvaging objects from water (structure if any that can create problems in the flow of the river)
• Be part of restoring the dam and accessibility
• Restoring Teesta Valley

Our objective:

Teesta V Hydropower Project Restoration

A part of the Dam Gate weighed 40 tons broken and fell in Teesta water which was making problems in power generation which was affecting the local area. We had to erase the objections.

Our suggestions:

After a detailed site visit and understanding of the difficulties of the situation along with the emergency response and financial bar we recommend, 4 pcs of Underwater lift bag with the capacity of 10 tons each.

Underwater lift bags are also known as Surface–Buoyancy-Lift Air Bag. These bags are made of heavy-duty UV-resistant PVC/PES/PU coated polyester fabric that gives it high tenacity and superior elasticity. Multiple inflation valves and marine belt hooks make it perfect for marine water towing usage. The shape of the bag provides it with an ultimate buoyant capacity teardrop with a single-point lifting contact. They are best suited for salvaging marine structures from deep waters. All of our disaster management bags come with a spring-loaded relief valve for excess pressure release. These are very easy to handle with a large variety and different tonnage capacities.

Project Status:

4 pcs of underwater lift bag with the capacity of 10 tons each was delivered for this site requirement. They were able to make float almost 40 tons of dissolved gate. This way the project goal was met well. Electricity and accessibility were restored to the damaged area of Sikkim.

NHPC Teesta Stage-V hydropower project was totally restored.