Rolwaling Diversion Scheme, Nepal

The project lies at the base of the Higher Himalayas, about 100 km north-east of Kathmandu and 8 km south of the Chinese Tibetan border.

The project will divert water during the dry season from the Rolwaling valley to the Upper Tamakoshi reservoir for hydropower generation. It consists of:
– an approx. 4 m high concrete intake weir on the Rolwaling River
– an approx. 6 km long 14 m² free-flow tunnel
– an outlet structure discharging into the Upper Tamakoshi reservoir
– 147 MW generating capacity in the Upper Tamakoshi powerhouse cavern
– a ropeway to provide permanent access to the intake

ClientUpper Tamakoshi Hydropower Limited (UTKHPL)
Executionsince 2015
Technical Data
  • Diversion tunnel capacity
approx. 22 m³/s
  • Free-surface flow tunnel cross section
approx. 14 m²
  • Total estimate cost
approx. 50 million US$
  • Additional capacity at Upper Tamakoshi
47 MW
  • Annual production from the diverted water
153 GWh
  • Comparison of alternatives
  • Topographic survey and river discharge measurements
  • GLOF risk assessment, including review of early warning system
  • Conceptual design of a permanent ropeway
  • Detailed tender design of the diversion tunnel and intake works
  • Construction cost estimate, construction planning and scheduling
  • Preparation of tender documents

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