Kathmandu, January 8
The government has proposed to construct a 100 m high dam in Shivapuri Dhap to increase water flow in the Bagmati River.
The High Powered Committee for Integrated Development of the Bagmati Civilisation is running a pilot project for the purpose since the last six months. The committee said the project was expected to be completed in the next 18 months.
As part of the project, a 24 m dam is under construction in the watershed area of the Bagmati River. The design of the 100 m high dam will be prepared on the basis of findings of the pilot project.
“We have not yet estimated the budget for the high dam project as we are still running the pilot project,” Rajesh Prasad Singh, project manager at HPCIDBC, told The Himalayan Times, adding that the objective of the project was to maintain the Bagmati River’s water level at 3 to 4 m even during the dry season.
According to Singh, the proposed high dam would store 8 million cubic meters of water to generate 2.12 megawatts electricity. The under construction dam currently occupies 12.4 hectares of land in Mulkharka VDC of Kathmandu.
The dam would store 8,50,000 cubic meters of water, which would be released at the rate of 400 litres per second during dry season after the project is completed. The Asian Development Bank has invested Rs 520 million in the project.
The Bagmati River originates from Baghdwar of Shivapuri hills to the north of Kathmandu Valley. The river is fed by numerous tributaries originating from the Mahabharat and Siwaliks range before it reaches the Tarai at Karmaiya and to the Gangetic plains. The total catchment area of the Bagmati River is about 157 square km with a length of 44 km from its origin at an elevation of 2,732 m to Katuwaldaha, which lies at an elevation of 1140 m.
The Bagmati Action Plan (2009-2014) had focused on the part of the Bagmati River and its tributaries within Kathmandu Valley. Major tributaries of the Bagmati River in the Valley include Manahara, Dhobikhola, Tukucha, Bishnumati, Balkhu and Nakkhu rivers.
According to the action plan, decrease in water discharge exerts enormous impact on the overall river ecosystem by damaging the habitat of aquatic life, exposing the river banks and channeling the flow. Discharge record from the Department of Hydrology and Meteorology for 1975-1999 at Sundarijal station revealed decreasing trend of water discharge.
While there are frequent high discharges at the time of flood in the Bagmati River, the overall trend is decreasing. The tapping of water for drinking and irrigation purposes from main sources of rivers is a root cause of decreasing water discharge.
Sundarijal, upstream Bagmati, Bishnudwar of Bishnumati, Sangla River, Nallu River, Godavari River, Mahadev Khola and Dudh Pokhari are major locations where huge volume of water is being diverted daily for drinking and irrigation purposes.
According to NTNC (2004), about 30 million litres of water is tapped everyday from rivers such as Bagmati, Bishnumati and other small streams originating from the Shivapuri hills.
Water from rivers such as Manahara, Nakkhu and Balkhu is being utilised for agriculture, industries, tourism and recreational activities.
A version of this article appears in print on January 09, 2017 of The Himalayan Times.