Melamchi Water Construction Kathmandu Air Pollution
April 09, 2017-Kathmandu This could be bad news for denizens seeking respite from the dust pollution in Kathmandu Valley, which can partly be contributed to the digging up of roads for the ongoing work on Melamchi Water Supply Project (MWSP). The snail-paced construction of the diversion tunnel of the project is most likely pushing the deadline further back from October.
The government had committed to bring the highly expected Melamchi water into the Valley by October 15. However, this is highly unlikely. The project developers have completed construction of about approximately 27 km of the diversion tunnel of the MWSP by April 1.
Hindrance by weak rocks
According to the Melamchi Water Supply Development Board (MWSDB), the area through which the tunnel is to be excavated is filled with weak rock formations. About two kilometres of this tunnel is to be excavated in rock masses of very poor quality. Technicians at work say that weak rocks make the excavation tough which is necessary for tunnel construction.
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The diversion tunnel is being excavated by drill and blast method in order to divert 170 MLD of raw water from Melamchi River to Sundarijal outlet where the raw water will be treated before sending it to the Bulk Distribution System (BDS).
The speed and efficiency of excavation is currently reduced by 50 per cent. Deputy Resident Project Manager at the board, Shiva Sharma told THT Perspectives that the speed of excavation is now 11 metres per day, down from 25 metres per day in the past months. He said, “We use the drill and blast method to excavate, and because of weak rocks the method is proving to be inefficient. The workers are putting in extra effort to support the weak rocks while drilling and blasting which is time consuming and elongates the process.”
According to him, the tunnel has been divided into three parts and in March only 495-mt of one part of the tunnel could be excavated. Out of the total 27-km, 4.11-km remains to be excavated. He said, “At the rate the excavation work is going, we may not meet our target. We need about 125 days (almost four months) to excavate two kilometres of the difficult part of the tunnel. It seems impossible for us to complete the task on time given the level of difficulty involved.”
According to MWSDB, it had not anticipated this problem, and the target was set not taking into consideration the possibility of weak rocks. One phase of the tunnel construction, from Sundarijal to Sidhu, had been completed a few months ago, on December 28, 2016. The tunnel was 9.4 km long, the longest tunnel of the three.
Lack of machinery and equipment
About one-and-a-half months ago, the contractors in charge of the tunnel construction had asked for new machinery and equipment in order to ease the excavation of weak rocks.
Secretary of Ministry of Water Supply and Sanitation, Bhim Prasad Upadhyaya confirmed that about the contractors had placed a request for the machinery and equipment needed for the excavation.
“The available machines and equipment are not sufficient to excavate the weak rocks. We have already provided Rs 30 crores as advance to the contractors for the purchase of new required machinery and equipment,” he said. He said that the contractors received the amount on March 19, 2017.
Sharma informed that the contractors have only used small rollers and dozers so far. He said, “The available machines and equipment are almost three years old and less efficient in excavating weak rocks. Some equipment have already been received and some others need to be bought.”
He also said that the drilling and blasting methodology to excavate the rocks has not been effective. “That is why we require new different advanced technologically sound machinery to apply suitable methods. The new machines with advanced technology will freeze the weak rocks making excavation easier.” He believes that the new machines and equipment would increase the speed of excavation from 11-mt per hour to 20-mt per hour.
Commitment as it is
Although the speed of progress points towards delay of the deadline, the government is still committed to make good on its promise.
Upadhyaya claimed that MWSP will not cross its deadline again. “We are eager to celebrate next Dashain in Kathmandu Valley with the arrival of Melamchi water,” he said.
Problem in water supply
Reportedly, there are about 35 lakh people residing permanently and temporarily in the urban part of Kathmandu Valley. The Kathmandu Upatyaka Khanepani Limited (KUKL) said that the average demand of drinking water within the Valley is 35 crore litres per day, and 45 per cent of the water is being supplied through underground sources. According to geologists, the water level of the Valley is decreasing by 3.5 to 50 centimetres per year which sets alarm bells ringing because the Valley cannot depend on underground water sources for the long-term.
The water distribution channel inside the Valley is 125 years old; pipelines in different places are rusty, broken and creaky. Forty per cent of that water supply is wasted due to leakage.
Lila Prasad Dhakal, Spokesperson of Project Implementation Directorate, said that MWSP will not be able to meet the current and the probable future water demands of the Valley. He said, “The Melamchi water supply is not sufficient to quench the thirst of average 50 lakh people in and outside the Valley. We cannot rely on just one source of water supply.”
The average supply of the water is 10 crore litres per day during winter and 16 crore litres during the rainy season which falls short of the demand. Under the Melamchi Drinking Water Sub-Project-II with assistance from Asian Development Bank, the distribution system, transmission main and water reservoirs are under construction in order to improve the water distribution process.
Started on December 21, 2000, the MWSP is a project assisted by the ADB, which aims to reduce the problems of drinking water scarcity in the Valley.
This project consists of two components — Melamchi Diversion Scheme and Water Treatment Plant. The contract for construction of headwork and tunnel was awarded on February 19, 2009 with intended completion date of September 2, 2013. The actual physical works started in April 2010. But due to the unsatisfactory performance of the contractor, it was terminated on September 25, 2012.
The project covers parts of the Indrawati and Bagmati watersheds and is spread over five districts. Key water diversion facilities are located within Sindhupalchowk and Kavrepalanchowk districts, whereas the water treatment plant, water distribution centre, and the ancillary structures are located within Kathmandu Valley.
The Melamchi Project envisages supplying 510,000,000 litres of water per day to the Valley from the Melamchi, Yangri, and Larke Rivers of Sindhupalchowk District. In phase one, the project will supply 170,000,000 litres of water per day to the Valley.
In 2008, the total cost of the Melamchi Diversion Scheme Sub-Project-I was $249.40 million. However, the cost was increased as the contract was extended due to the delay in construction of tunnels. For the extension of the project, the government added Rs 13.08 million and ADB added 25 million on April 7, 2014. The total cost is now estimated at $287.4 million.
Source: The Himalayan Times Perspectives