Why in News?
On April 29, 2026, UNESCO joined forces with Sikkim's Department of Science and Technology (DST) to scientifically document the engineering of Ru-Soam bridges.
Cultural Significance
- Lepcha Heritage: "Ru-Soam" is a Lepcha term where 'Ru' means cane/rattan and 'Soam' means bridge.
- Indigenous Engineering: These are traditional cane suspension bridges built by the Lepcha community, primarily in the Khangchendzonga Biosphere Reserve.
- Historical Recognition: They were famously described as "the most characteristic of Himalayan object art" by British botanist Sir J.D. Hooker in 1848.
Construction & Engineering
- 100% Natural Materials: Built entirely from wild cane, bamboo, and wooden logs sourced from nearby forests.
- Zero-Carbon Design: They leave no carbon footprint and use materials that naturally regrow within 3–5 years.
- Structural Components:
- Soamgyang: Two parallel main canes tied to trees at either end to keep the bridge suspended.
- Ahool: Swinging cane loops that provide structural support and stability.
- Soamgur: Bamboo decks that form the walkway.
- Capacity: These bridges can span up to 100 metres and typically support 2–3 people crossing at a time.
Modern Relevance
- Disaster Resilience: Their flexibility allows them to withstand the high-velocity water and debris of floods that typically destroy rigid steel or concrete structures.
- Scientific Study: The current UNESCO project is assessing how these ancient principles can inform modern climate adaptation and disaster risk reduction strategies.
- Eco-Tourism: The government is promoting these bridges as sustainable tourism attractions in Lower Dzongu to support local livelihoods.
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