Rivers at Risk: Climate-Induced Pressure, Conservation and Water Security in the Eastern Himalaya

RABIJEETA LAHKAR

A bird’s eye view of the Eastern Himalayan Region (EHR) is no less than magic. Lofty mountains and giant glaciers crown the region while a complex web of rivers traverse through the region ending in the Bay of Bengal.

These rivers are fed by glacial melt, seasonal rainfalls and forest watersheds – acting as a lifeline for the millions of people living in the region. But ecological degradation and climate induced crises pose a severe threat to the region’s river systems, exacerbating both – ecological and human vulnerabilities across the region.

Melting Glaciers, Shifting Systems

The EHR is part of the Hindu Kush Himalayas, home to the “Third Pole”, which holds the largest volume of fresh water outside of the polar caps. It provides water for drinking and agriculture to almost one-seventh of the global population. But this feat is less to be celebrated and more to be concerned about given how fragile this ecosystem is to the impacts of a warming planet.

According to the International Centre for Integrated Mountain Development (ICIMOD), the region is amongst the hardest hit by a changing climate as the glaciers continue to retreat rapidly, losing nearly one-third of its ice between 1980 and 2010. But melting glaciers are just the tip of the problem here. They set off a chain reaction, leading to unusual river swells, increased river volumes downstream and changing river courses.

As a result, downstream communities face heightened vulnerability to seasonal variability i.e. greater risk of water scarcity during dry seasons and flood risks during monsoons. In recent years, the risks of Glacial Lake Outburst Flood (GLOF) have also increased in the region.

A stark example is the 2023, Sikkim GLOF which claimed many lives, triggered about 45 landslides and destroyed the Teesta III dam thus disrupting life in the region. Such incidents further compound the region’s vulnerability to climate risks.

David vs Goliath – River Islands in a raging Brahmaputra

Nestled between the Brahmaputra and Barak Valley, Assam has a very extensive and diverse river system with major rivers like the Barak, Dibang, Manas, Lohit, Kushiyara etc. flowing through the state.

The Brahmaputra, largest of all of them, cuts through the entire state and holds immense significance for people whose lives and livelihoods completely depend on the flow of this river. Majuli, the world’s largest riverine island, lies in the midst of the Brahmaputra River and plays a key role in shaping the socio-economic and cultural fabric of the island communities.

Among the clusters of smaller islands around Majuli is Kartick Chapori where life revolves around agriculture and fishing – both activities relying on historically predictable water cycles. However, in the face of climate change, erratic floods have begun to affect crop productivity as standing crops get washed away while dry spells result have led to a reduced fish catch as erratic currents and temperatures disrupt breeding cycles.

Additionally, soil erosion is slowly eating away the landmass thus threatening the livelihoods of the people. Recent studies have suggested that there is an increase in the frequency and duration of floods in the Brahmaputra basin as a result of changing rainfall patterns and glacial melt.

For river-dependent communities, these changes have slowly become the “new normal”, increasing their risk exposure and compounding their vulnerabilities. Shown below is a historical imagery of Kartik Chapori for the years 2005, 2015 and 2025 suggesting how over the years, Brahmaputra river has changed course and inundated the island in its might. This has led to loss of agricultural land and depriving the communities of water which again led them to change their habitation over the years.

Rivers – EHR’s Lifeblood

The region’s extensive river system not just caters to human life but also helps sustain the rich and diverse ecosystems. From grasslands of Kaziranga National Park to the swamp forests of Dibru-Saikhowa National Park, the Brahmaputra nurtures vibrant habitats – home to many endemic and endangered species such as the Gangetic Dolphin and the Golden Mahseer etc.

However, the riverine ecosystem faces threats from unchecked infrastructure development in the form of dams, roads and highways along with sand mining, deforestation and pollution. These anthropogenic pressures weaken the river’s ability to self-regulate leading to shrinking biodiversity. For instance – Assam’s wetlands have played a critical role in acting as a strong buffer during floods by absorbing excessive water and containing it away from human civilization.

But due to rampant extraction, illegal encroachment and pollution, wetlands are slowly dying, throwing the region’s local ecology off-balance. Deepor Beel – a popular Ramsar site located on the outskirts of Guwahati stands as a case study for us to urgently rethink how we look at wetlands – not as a standalone water body but as an extension of the river itself.

Redemption through Nature based Solutions

We are faced with a layered crisis – climate change, environmental degradation, glacial melt, erratic rainfalls – all of which are taking a toll on our river systems. This requires us to move away from traditional responses like relying on grey infrastructure – think dams and embankments to more ingenious solutions based in nature itself.

Deploying Nature based solutions (NbS) like restoring forests and reviving wetlands have proven to be highly effective in building ecological resilience. Restoring forests stabilizes the soil, reducing sediment loads and minimizing the risk of erosion and downstream flooding. Similarly, wetland restoration aids aquifer recharge and improves flood water absorption.

Community led reforestation in Assam has demonstrated encouraging results against the unpredictable forces of nature and offer a great opportunity to build long-term resilience strategies.

Today, rivers of the EHR are changing, and changing with them the region’s geography, ecology, economy and society. Climate impacts and ecological degradation are the two major drivers of this change. But with a proactive approach, the impacts can be mitigated.

It is only imperative that we start thinking of rivers as the “veins of regional ecology”. We must invest heavily in NbS as core ecological infrastructure. Since rivers follow their own rhythm, we must strategically think about strengthening transboundary water governance while planning for flood management.

The security of the EHR is intrinsically linked to the hydrological future of South Asia and it will require a concerted effort from the policymakers, scientific fraternity while appreciating deep-rooted traditional community wisdom.

Rabijeeta Lahkar: An experienced and motivated researcher and trainer working in the social sector with expertise in child rights and child participation.

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