RUINATION OF MELAMCHI MULTIPURPOSE PROJECT
Parliamentary Committee Could Save it
AB Thapa
The Melamchi Water Supply Project to be implemented with the assistance of the Asian Development Bank is in the focus since a long time because this project is lifeline for more than a million people living in the capital Kathmandu and its environs. This project could also solve the problem to supply cheap electricity to the entire country for quite some time. Unfortunate even such a strategically important project has not been spared from being mishandled. The huge investment in Melamchi Project would virtually go down the drain if we failed to correct our recent decisions to ignore the findings of the UNDP supported feasibility study of this project. This project could be a great liability to the nation.
It is still not too late to save this very important project. It is heartening to learn that the Melamchi issue is being studied by PARLIAMENTARY COMMITTEE. The Parliamentary Committee should go through the reports and published materials, and it should seek information from competent experts also.
How Public Interest Sacrificed
The Melamchi Project feasibility study report prepared with the assistance of the UNDP explains that around the time 2011 the total system demand for water supply ( in Kathmandu valley) is expected to reach the total supply from in-valley surface sources and Melamchi. Thereafter the next stage of the development of the Melamchi will be required. This entails diversion from the YANGRI and LARKE rivers that flow to the east of the Melamchi. Water would have to be diverted by tunnels to a point upstream of the Melamchi intake. The total length of the delivery tunnels is expected to be over 12 kilometers.
The Larke and the Yangri are the main tributaries of the Indrawati River. After the diversion of the Yangri and Larke rivers into the Melamchi there would hardy be any flow in the upper reach of the Indrawati River during the dry season.
It saddens anybody to learn that the Indrawati River has been recently leased out to private developers to build a cascade of hydropower. One hydropower is already completed and the others are at planning stage. We see no justification for the decision to lease the Indrawati River to private developers to build a cascade of hydropower. Could not we find some other suitable rivers any where in Nepal to be leased out to private hydropower developers?
Melamchi Tunnel Hydropower
There exists a big potential to generate cheap electricity by using the diverted flow of the Melamchi River The elevation of the Melamchi intake weir is 1715 m and the inlet to the treatment works near Sundarijal is 1409 m. Thus there is an enormously big gross head of 306 m. The UNDP report has clearly stated that the net increment in investment ( the cost of the powerhouse located near Sundarijal with electromechanical equipment) needed to implement the hydropower element is relatively small as the intake headrace tunnel and penstock are already in place for conveying water to the treatment works. According to the feasibility report of the Arun-3 Project operating at a head of about 300 meters ( same as the Melamchi Hydropower ) the cost of electromechanical equipments and power station civil works is only about 30% of the total project cost. The UNDP study has concluded that it would be worth constructing the hydropower and it could make a contribution to reducing the cost of drinking water to Kathmandu. The UNDP report explains that even before the diversion of the Yangri and Larke rivers the total annual generation of the Melamchi hydropower would be 60 GWh and out of it the firm power generation would be 40.5 GWh.
The Melamchi hydroelectricity generation would be close to 50% of the annual generation of the Kulekhani No.1 hydropower project. After the diversion of the Yangri and Larke the electricity generation of the Melamchi hydropower plant would have been further increased.
It surprises anyone to learn that the Melamchi hydropower component has been dropped. Even the alignment of the tunnel has intentionally been slightly modified to preclude the inclusion of the hydropower component later on. We must seriously look into this matter to find out why the power component of the Melamchi project was allowed to be dropped despite the fact that the UNDP report has concluded that the power station would be worth constructing and could make a contribution to reducing the cost of drinking water to Kathmandu residents
Additional Use of Melamchi Tunnel
The 28 km long Melamchi tunnel to divert the Melamchi water into the Kathmandu valley is the most expensive component of this project. This tunnel, apart from diverting Melamchi water into Kathmandu valley, could be developed as a trunk tunnel to provide transit to regulated flow of the Langtang river, and also the waters drawn from the Yangri and Larke rivers. Such conversion would not involve additional investment. A small portion of the combined flow of these rivers sufficient to meet the long term demand for water in the Katmandu valley could be provided for free after the generation of electricity at hydropower station located near Sundarijal. The bulk of the water could be dropped into the Kulekhani reservoir to generate abundant cheap electricity. Water thus pumped into the Kulekhani reservoir after being used for power generation in a cascade of hydropower stations (Kulekhani Nos 1,2 and even 3) could also be used to provide gravity irrigation in Chitwan valley.
The Langtang Power Projects
The Langtang projects operating at a head of about one thousand meters and more could produce electric energy at very low cost . Apart from it, water in abundant quantity could be supplied to the Kathmandu valley for free. The concept of the Langtang project solely for power generation was developed under the UNDP supported Gandak basin masterplan study . This concept required some revision to include a new component to supply drinking water to Kathmandu valley. It necessitated dropping the regulated Langtang water at the end into the Melamchi river instead of the Bhotekosi (Trisuli).
According to the Gandak Basin Master Plan a 120 m high dam has been proposed on the Langtang Khola near Jaithang. The volume of the reservoir would be about 180 million cubic meters. Based on revised concept the water in the reservoir at a full supply level of 3995 meters would be first tapped by the Langtang-1 power station operating at a gross head of 950 meters. The installed capacity of this Langtang-1 power station located near Ghore Tabela about 15 km downstream from the storage reservoir would be about 70 MW.
Water from the Langtang-1 power station would be directly drawn into the Langtang-2 power station. For augmenting this flow the water from the catchment downstream of the storage dam would also be drawn into the headrace tunnel of the Langtang-2 power station. The installed capacity of the Langtang-2 power station operating at a head of about 1300 meters would be about 150 MW.
Why is Langtang Power Cheap?
Of all the site characteristics, head is the most important. Design guidelines, 1989 approved by the American Society of Civil Engineers has given some simple reasoning that would help to explain why the super high head Langtang power stations operating at many times greater head by comparision with other hydropowers could be built at very low cost. "Very simply if one doubles the head the quantity of water needed to produce a certain amount of energy is halved, Thus, for like site energy development the penstock area and reservoir volume are halved and further large cost reductions occur for powerhouse and machinery costs. This fundamental consideration is at the root of the large cost reductions that occur at higher heads."
Design guidelines, 1989 approved by the American Society of Civil Engineers has given some simple reasoning that would help to explain why the super high head Langtang power stations operating at many times greater head by comparision with other hydropowers could be built at very low cost. "Very simply if one doubles the head the quantity of water needed to produce a certain amount of energy is halved, Thus, for like site energy development the penstock area and reservoir volume are halved and further large cost reductions occur for powerhouse and machinery costs. This fundamental consideration is at the root of the large cost reductions that occur at higher heads."
A joint team of German, Japanese and the US consultants has made an interesting reference to a Canadian high head project vis-à-vis the Upper Arun project to be operated at moderately high head. "It is worth mentioning that the search of the worldwide inventory of the existing hydropower installations identified only one plant with a combined head and flow magnitudes greater than that of the Upper Arun - Kemano in British Columbia, Canada". At present the electricity generated by the 896 MW Kemano Project with a 16.3 km long headrace tunnel operating at 800 m head provides power for Alcan's aluminum smelters at Kitimat at a cost below US cents 3 per KWh.
Water Supply To Kulekhani Projects
The electricity generation of the Kulekhani projects could be increased by 3 times if the combined flow of the Melamchi and the Langtang after setting aside adequate quantity of water for Kathmandu valley is delivered into the Kulekhani reservoir.
Still Not too Late
In the past the Asian Development bank had been very flexible. They fully cooperated to make substantial amendment to the agreement whenever they were convinced that there is a room to make any project economically and financially more viable. Kankai Irrigation Project could be a typical example.
Feasibility study as well as the detailed design of the Kankai Project was done under a grant directly by the Asian Development Bank outside Nepal. We from the Nepalese side expressed our reservation about the detailed design. After completing various formalities the Bank decided to finance the Kankai Irrigation Project. The construction of this project commenced from around the middle of 1970s.
We proposed the Asian Development Bank to amend the loan agreement by substantially modifying the total design of the project even though the contractors had already started the construction works at site. The modification allowed the capacity of various structures ( involving about 2/3 cost of the project) to be increased by about 60% absolutely without rise in project cost. The Asian Development Bank agreed to amend the Agreement. A Supplementary Loan Agreement was signed to incorporate funding for the construction of the infrastructures needed to further extend the canals and to provide services to cover additional areas.
