Bagmati River flowing by Pashupatinath Temple in Kathmandu. Image by Bryon Lippincott via Flickr (CC BY-ND 2.0).

• A proposed dam on Kathmandu’s Bagmati River aims to collect rainwater during the wet season and release it in the dry season to rejuvenate the river, but skeptics question its viability and safety.
• Concerns include environmental impact, potential destruction of trees, pollution, and the risk of dam failure in earthquake-prone Nepal.
• Political, ecological, and community-related questions remain unanswered, with some advocating for alternatives and further analysis before proceeding.

KATHMANDU — The Bagmati River, coursing through Nepal’s capital, Kathmandu, has transformed into a sewer canal in recent decades, with untreated raw sewage discharged into its waters.

Officials are now drafting plans to rejuvenate the sacred river, which also passes through the revered Pashupatinath Temple, by building a dam 95-meters (311 feet) tall to collect rainwater during the wet season and release it in the dry.

However, skeptics question the viability and long-term safety of such a dam, given the uncertainties posed by fragile geological conditions as well as climate change. As the dam may not only jeopardize millions of lives, but also inundate one of Hinduism’s holiest shrines, a UNESCO World Heritage Site, they call on the government to look for alternatives.

“The plan is to build a 95-meter-tall concrete face rockfill dam [CFRD] in the headwaters of the Bagmati inside the Shivapuri Nagarjun National Park,” said Nischal Chhatkuli, engineer and information officer at the Bagmati improvement project. “The project decided to pursue the idea of the dam after different studies conducted by various international agencies in the past few decades suggested that this could be one of the most suitable options,” he added.

Rain is the key source of water for the Bagmati, which makes it different from most of the other rivers in the country. Unlike the perennial snow-fed rivers in the Himalayas, the Bagmati is fed by spring water. But due to unplanned urbanization, the paving over of large areas in the basin, and the construction of roads along the riverbank, the natural springs are drying up: Rainwater runoff can’t percolate into the soil and recharge the aquifers. This means that these springs release less water into the river during the dry season.

The river, however, swells during the monsoon, when Nepal receives 60-90% of its annual rainfall in just four months, then diminishes to a trickle — as little as 3% of its peak — during the dry season when the only water flowing into the river comes from untreated sewage.

According to the project, the $190 million dam, which is to be funded by an Asian Development Bank (ADB) loan, will have the capacity to store 9.5 million liters (2.5 million gallons) of water and spread over 50.7 hectares (125 acres) of land (around 0.32% of the total area occupied by the national park). After the dam is complete, around 60 l (16 gal) of water is to be released into the river every second. This would be the second dam to be built in the area. The first one, known as Dhap Dam, located less than 2 kilometers (1.2 miles) away from the new proposed dam site on the periphery of the national park, is 24 m (79 ft) high with a capacity of 861,000 cubic meters (227 million gal) of water. Its water hasn’t been sufficient to drastically improve the flow of water, officials say.

The dams are a part of the government’s Bagmati River Basin Improvement Program, launched in 2014. The program’s objective is to restore the flow of water in the river and implement an integrated water resources management approach with the participation of residents of the basin.

“Building the dam is a stupid idea,” said Shrawan Kumar Sharma, a rights of nature campaigner. He said there are four main risks associated with the dam. “The first risk is that due to changing rainfall patterns, the dam may never be full to its capacity. That would jeopardize the whole rationale behind the project,” he said.

Another other issue is that thousands of trees, which serve as the lungs of the bustling capital city, will have to be chopped down to make way for the dam, Sharma added. According to Nepal’s law, 10 new trees have to be replanted for every tree chopped. “There’s simply not enough land to plant the trees. Also, several thousand sacks of cement will have to be opened to build the dam, and all the dust will eventually end up in Kathmandu,” he said.

The draft environmental impact assessment (EIA) report made public recently also states that different forms of pollution could affect the construction area and downstream due to muck disposal, possible leakage of toxic materials, and sound and air pollution due to construction activities. However, the report plays them down, saying that most of the effects are localized and impacts are short-term.

When the dam does come into operation, the chief risk is that of its failure given the seismic risks in the earthquake-prone country, the report states. It notes that the river flows through densely populated urban areas of Kathmandu Valley and four major religious sites, including Pashupatinath. “The tentative population that could be impacted from dam failure would not be less than 500,000 from Nagmati Dam to the exit point at Chobhar,” it says, adding that the failure of the dam would release 9.848 million l (2.6 million gal) of water into the Bagmati. “The religious sites of significant importance will be inundated from the flooding. Further, the high discharge can change its natural flow channel, shifting the existing river channel,” the authors of the report state.

Large-scale infrastructure projects in Nepal have been marred by corruption and mismanagement and some have even proven to be costly white elephants. While millions of dollars spent on new international airports in Pokhara and Bhairahawa have gone in vain, a large-scale water supply project diverting water to Kathmandu, also funded by the ADB, remains only partially operational due to natural disasters.

Similarly unprecedented rainfall, possibly linked to climate change, in the Indian state of Sikkim recently led to a dam collapse, killing several people downstream, said Biraj Bhakta Shrestha, a member of Parliament from the opposition Rastriya Swatantra Party.

But the dam breakage situation is highly unlikely, said Chhatkuli, the project engineer. He said that CFRDs can withstand seismic shocks and thousands of such dams are in operation around the world. “We badly need to rejuvenate the river as people are extracting groundwater at unsustainable levels,” he said. “Also, we’ve found bedrock in the area where the dam will be built,” he said, adding that this would help improve the dam’s safety.

In addition to the ecological challenges as well as concerns related to the safety of the dam, there are several political questions that remain unanswered, Shrestha said. “We talk about decentralized development, yet we are pouring huge investments into different projects in and around the capital only,” he said. “Also, we need to ask if the $152 million loan is worth it for the project whose aim is to just increase the flow of the Bagmati River,” he added.

Until recently, Nepal’s protected area laws didn’t allow for the construction of infrastructure such as dams and hydropower projects entirely within protected areas. However, the government changed that through an executive order to make it possible for hydroelectric projects and dams to be built entirely inside the core of protected areas.

Uday Raj Sharma, former secretary at the Ministry of Forest and Environment, said the whole idea of building a dam inside a pristine and ecologically important national park goes against the notion of conservation. “The government shouldn’t go ahead with it. If it is really bent on doing it, it should degazette the proposed dam area so that it falls outside the national park,” he added.

Then there’s also the question of what local communities living around the Nagmati stream want. “We are yet to talk about asking the local communities what they want,” said Narendra Man Babu Pradhan, country representative at IUCN Nepal. “We are taking the matter lightly, expecting the people to accept compensation from the government and surrender their land,” he said, adding that this may not be true.

As part of the river basin improvement program, officials also aim to revitalize the springs that feed the Bagmati, reduce pollution with a new sewage treatment plant, harvest rainwater, beautify riverside areas in the city, and implement an early flood warning system. However, all that seems to have taken a back seat, said Shrestha, the member of Parliament. He said that instead of building one high dam, several catchment areas could be identified to store water, thereby reducing the risk of flooding.

However, Chhatkuli said the project doesn’t have that luxury, as land is very scarce in the headwaters of the river.

The EIA report indicates that if the dam isn’t constructed, officials could allocate the financial resources to alternative projects. This would prevent wildlife habitat fragmentation and maintain it in its natural state. The land area initially earmarked for the project could be utilized for future development purposes. Additionally, the project implementation area would remain free from air, noise and water pollution stemming from construction activities. Moreover, densely populated downstream areas along the Bagmati River would be safeguarded against the potential devastation of high flood disasters resulting from an unforeseen dam failure.

However, there would be little possibility of improving the water quality of the holy Bagmati River as more and more domestic and industrial/commercial and human and animal waste is dumped into the upper reaches of the river. “Therefore, to dilute the increasing water pollutants and to maintain the river water quality both environmentally and religiously, implementation of this project is the best alternative,” it concludes.

Ganesh Pant, chief warden at Shivapuri Nagarjun National Park, said he disagrees with several claims made in the EIA report. “The EIA report seems to be superficial, as it lacks micro-level analysis,” he said. “Also, most of the comments and suggestions the Department of National Parks and Wildlife Conservation provided have largely been ignored,” he added.

Pant said the conclusion of the EIA seems illogical, as it says not building the dam would make the project irrelevant. “That’s not the case,” he added. “Let’s not rush into it. First, let’s look at the costs and benefits, look for alternatives,” he concluded.

This story was first published by Author in Mongabay on 22 February 2024