জুন 21, 2018
Nepal is one of the world’s most water-rich nations, with over 6,000 rivers and huge hydropower potential. But it is also one of the world’s most disaster-prone regions.
Nepal lies in the southern foothills of the Tibetan plateau, where many of its rivers originate. Dry winters and wet summers, combined with the unstable geology of the Himalayan region, mean that landslides and floods are common.
In August 2014 a major landslide near the Nepal-China border killed over 150 people and in October dozens died in an avalanche caused by heavy snowfall. Risks of disaster, compounded by other factors such as water shortages, are forcing people to move from the mountains down to the plains, further intensifying water shortages.
Dr S. M. Wahid and Dr Arun Shrestha, hydrologists from the International Centre for Integrated Mountain Development (ICIMOD), argue Nepal needs regional cooperation on disaster warning systems and development of water resources.
chinadialogue (CD): Nepal has plenty of water, yet there is a shortage of water for domestic and agricultural use. Why is this the case?
S. M. Wahid (SW): Nepal is a mountainous country with ample water resources but the majority of these resources cannot be used, as they are made up of, for example, concentrated rainfall or torrents created when ice dams break.
Nepal has a monsoon climate and its winters are very dry, with hardly a drop of rain. Then in summer there is a huge quantity of rain. This means the country has 40,000MW of hydropower potential – 153 times what we currently import from India.
The problem with managing water in Nepal is that if the wet season becomes wetter, we will suffer more floods, while if the dry season becomes dryer (according to IPCC scenarios) there will be even less water for farming.
Although there are floods in the plains, the situation is worse for people in the mountains, where disasters are harder to predict. Also, water resources flow away faster in the mountains, and without water it’s impossible to farm. So people are moving away and will continue to do so in the future. Many people have already moved to Kathmandu, putting huge pressures on infrastructure and resources. We need to take action quickly.
Alongside migration, population growth is also exacerbating the problem of water shortage. In the Nepalese part of the Koshi basin (a river which flows through China, Nepal and India), the population is set to increase by 45% by 2050.
CD: What is causing the depletion of water resources?
SW: The biggest reason is people moving from the mountains to the plains.
For generations, people have relied on water from springs, but the number of springs is slowly decreasing, with some completely drying up. Why? In the past people living in the mountains built small reservoirs or ponds for their own use. That water would seep through the ground and flow out at a lower altitude, forming a spring. But so many people have moved from the mountains that those reservoirs aren’t being maintained and the springs are drying up.
But people don’t realise that without those ponds, the springs further down dry up.
Now the plains are so crowded, building reservoirs are necessary to provide water and reduce migration from the mountains.
CD: What can be done about frequent natural disasters and water shortages?
SW: The public lacks relevant information and understanding. People in the mountains need to know about possible disasters. But that’s a common problem. Climate change is already happening too fast for people to keep up with, and what the people of Nepal need most now is better technical support and information on disasters.
We need to establish reliable channels to bridge that information gap. Many of Nepal’s rivers flow across international borders, and that means countries need to work together to predict what disasters will happen where. We also need early warning systems and training so that people can act promptly.
To solve the water shortage, we need reservoirs, both big and small. Our water is unevenly distributed over the year, and so storage is particularly important and there’s huge potential for doing this. The Koshi River basin alone could store 8 billion cubic metres of water and there is only a demand for 6 billion.
CD: There have been reports that, given the particular geology of the region, reservoirs and dams could increase the chances of landslides. What’s your view?
SW: Our project — the Koshi Basin Water Management Project — hasn’t yet looked at the link between landslides and reservoirs. But we can assume that there are some areas prone to landslides, and others that aren’t. Reservoirs are essential for Nepal, so we’ll just have to make sure we build them well. Of course, we do need more research into the links.
CD: Nepal has huge hydropower potential, but the country’s engineering capacity is weak. What are the main concerns about hydropower development?
Arun Shrestha (AS): A lack of know-how is a problem for dam building in Nepal, but it’s not the biggest problem. One of our main concerns is funding. Nepal should consider getting international funds to construct hydropower.
A second issue is potential markets. You want to think about who might use the electricity you generate. India is a huge potential market for Nepal. Once you’ve identified the market you need to negotiate the price and the building of transmission networks.
Nepal’s current and future demand for electricity is small when compared to what we could generate. Currently we generate 800MW, but use 2,000MW, so we import some power from India. Nepal has the potential to generate 40,000MW, so that may change.
CD: Glaciers on the Tibetan plateau, upstream from Nepal, are melting due to climate change. How will that affect Nepal? What can China do to reduce the impact of disasters in Nepal?
AS: China can help us by monitoring rivers within its borders and warning us of problems. There are many ice dams which cause floods or landslides when they break, resulting in huge losses in Nepal. If China warns us, we can react in time.
Currently there’s no data to show that climate change has led to worse disasters, but with the melting of glaciers, disasters will become more frequent.
There are actually pros and cons of melting glaciers. It’s good if there is more water, but it’s hard to be sure when it will come, and how much.
SW: The negatives outweigh the positives. Hydropower needs a sustained flow. If there’s too much water, the reservoir can be damaged, if there’s too little you can’t generate power.
Dr S. M. Wahid and Dr Arun Shrestha are hydrologists with ICIMOD.