Melamchi Water Supply Project (MWSP) is a project to supply drinking water to Kathmandu Valley by diverting 170,000,000 litres (45,000,000 US gallons) of water per day. The project started in 1998 and completed in 2021. The intake of this project is located in Melamchi, Nepal. Ministry of Physical Infrastructure and Transport (Nepal) is the executing agency for the Project and Melamchi Water Supply Development Board is the implementing agency.
The intake of the project lies in the Melamchi valley in the gorge below Ghwakan, just upstream of the confluence of Melamchi River and Ribarma Khola. The main structure is the diversion weir, river-training structures, and sediment exclusion basin. A gravity concrete weir is 5 to 7 m high with the crest at an elevation of 1,425 m asl. The control system and the sediment exclusion basin have a design capacity of 6m3/s. The sediment exclusion basins are double-chambered with a length of 80 m each.
The tunnel intake is at an elevation of about 1416m and the outlet is about 1,408 m asl. The length of the tunnel from the intake to the water purification facilities in Kathmandu Valley at Sundarijal is about 26 km. The tunnel is longest water supply tunnel of South-Asia and second longest water supply tunnel of Asia. The tunnel is being excavated from adits at Ambathan, Gyalthum, Sindhu and Sundarijal waterfall. The diversion flow in 6m3/s. The tunnel has a cross-sectional area of 12.7 m2 and lined with shotcrete in most of the section; concrete lining is done only in the weak rock formation. The tunnel is excavated by drill and blast method. The geology of the areas consists mainly of gneiss with mica schist and laminated quartzite.
The distribution work has nine service reservoirs at various locations in the Kathmandu (Mahankalchaur, Bansbari, Paani Pokhari, Balaju, Khumaltar, Arubari, Tigni, Katunje and Kritipur). The water from Sundarijal to service reservoir is supplied by a Bulk Distribution System (BDS). The distribution to household is done by a network of pipes about 670 km long. About 540 km of sewerage network will also be upgraded in this project.
The project had a serious history of delays.
- In 2007 August, the ministry of physical planning, Hislia Yami, cancelled the contract awarded to UK company Severn Trent clamining that Severn Trent did not have a sufficiently strong international track record.
- In September 2012, the contract with China Railway 15 Bureau Group Corporation was terminated.
- In 2018, the deadline was extended to mid-February 2019 with CMC, the contractor.
- In 2019, the contract with Cooperativa Muratori e Cementisti di Ravenna (CMC) was terminated over payment dispute.
- 2020-July 14: During testing of the tunnel, the breaking of bulkhead gate caused flooding in the tunnel resulting in the death of two staff.
- 2021-June 15: Due to monsoon flood, the headworks of the project at Ambathan area was blocked by flood. Temporary structures such as construction camps and Bailey bridges swept away. Eight workers including three Chinese, three Indians and two Nepalis were washed away by the flood.
- In 2005, Prime Minister Sher Bahadur Deuba was charged for corruption by the Royal Corruption Control Commission. The case was terminated by the Supreme Court considering it as an unconstitutional move by King Gyanendra.
- In 2006, Sweden withdrew its funding of this project over corruption issues.
- In 2019, the contractor Cooperativa Muratori e Cementisti di Ravenna (CMC) alleged two senior Nepali bureaucrats Gajendra Kumar Thakur, a former secretary at the Water Supply Ministry, and Surya Raj Kadel, executive director of the Melamchi Water Supply Development Board for a cut of 3% of payment on NPR 300 million payment. This issue lead CMC to break the contract with the government.
- "Project Description | Melamchi Water Supply Development Board". www.melamchiwater.gov.np. Archived from the original on 17 June 2020. Retrieved 10 March 2021.
- "Sweden withdraws aid commitment to Nepal water project - Nepal". ReliefWeb. Archived from the original on 22 June 2021. Retrieved 10 March 2021.
- Ghanashyam, David Lees, and A. Niaz. “The Melamchi Water Supply Project,” 2015
- "KUKLPID". www.kuklpid.org.np. Archived from the original on 6 August 2020. Retrieved 10 March 2021.
- Global Corruption Report 2008. Transparency International. 2008.
- Bhushal, Ramesh, July 17, and 2013. “China-Backed Projects Create Controversy in Nepal.” The Third Pole (blog). Accessed June 20, 2020. https://www.thethirdpole.net/2013/07/17/china-backed-projects-create-controversy-in-nepal/ Archived 27 December 2017 at the Wayback Machine.
- Times, Nepali. “Melamchi Delayed by Government Extortion.” Accessed June 19, 2020. https://www.nepalitimes.com/from-the-nepali-press/melamchi-delayed-by-government-extortion/ Archived 22 June 2021 at the Wayback Machine.
- “The Rising Nepal: Lingering Pipe Dream.” Accessed June 20, 2020. http://therisingnepal.org.np/news/34415[permanent dead link].
- “PressReader.Com 世界の新聞.” Accessed June 20, 2020. https://www.pressreader.com/nepal/peoples-review-9d48/20190717/281698321328402 Archived 22 June 2021 at the Wayback Machine.
- "Two employees of Melamchi Drinking Water Project missing in tunnel accident". Archived from the original on 16 July 2020. Retrieved 24 July 2020.
- "Melamchi Drinking Water Project's tunnel bursts; two swept away". The Himalayan Times. 15 July 2020. Archived from the original on 17 July 2020. Retrieved 24 July 2020.
- "Melamchi project headworks buried in mud, extent of damage unknown". Archived from the original on 18 June 2021. Retrieved 22 June 2021.
- Machamasi, Amit. "Nepal valley suffers quadruple disaster". Archived from the original on 22 June 2021. Retrieved 22 June 2021.
- Department Of State. The Office of Electronic Information, Bureau of Public Affairs. “Conviction of Former Nepalese Prime Minister.” Accessed June 20, 2020. https://2001-2009.state.gov/r/pa/prs/ps/2005/50297.htm Archived 30 April 2021 at the Wayback Machine.
- “Nepali Bureaucrats Regularly Asked for ‘Their Cut’ from Melamchi Contractor, Italian Officials Say.” Accessed June 19, 2020. https://kathmandupost.com/investigations/2019/03/21/nepali-bureaucrats-regularly-asked-for-their-cut-from-melamchi-contractor-italian-officials-say Archived 3 June 2020 at the Wayback Machine.