The section of the Himalaya between the Kangchendzonga spur in the west and the Chumbi Valley in Tibet to the east – alternatively known as the Sikkim-Darjeeling Himalaya, is an ecologically and culturally unique landscape and a steep mountainous region. In recent decades, it has been under increased pressure for infrastructure development of roads, power generation dams and tourist and military facilities due to its scenic value and geopolitical location.
Livelihood and connectivity-based development are inevitable and have had some public support to bring the region closer to the rest of India in terms of economic diversification. However, using the mountain topography to generate electricity for the forever energy-hungry people has had ambiguous support. Most of the power generated from the four dams on the main Teesta river supplies the needs for energy in the rest of the country since the intensity of industrial and domestic use is much more in the plains below.
The centralised generation of electricity is considered a relatively clean way to use energy. However, the long-term assessments of even non-fossil fuel-based energy like hydroelectric dams aren’t assessed correctly. The power generation utilities are government-owned, with immense power over the lives of the local people and several state resources at its disposal.
They also ostensibly give some diversity of jobs in an otherwise low economic diversity region, have strong provincial or district-level political backing through complex economic relationships and allow the manifestation of economic development in such remote and difficult landscapes. The economic case is also made by revenue generation for the provincial governments through royalty payments.
Unfortunately, the ecological case for hydel dams is harder to make. The Sikkim-Darjeeling region is among the most unstable mountain regions in the world, with intense seismic activity, extremes of climate due to the terrain, and houses some of the most biodiverse regions of the Earth.
The creation of long-term infrastructure like dams in these areas, to generate relatively small amounts of energy after extensive and permanent physical damage to the hills and valleys and loss of scenic and biodiversity value is never taken into consideration. Nor are long-term negative repercussions to the landscape, local climate and actual assessments of environmental impacts properly conducted.
The author and his co-workers assessed two of the lower dams on the Teesta River, the lifeline of Sikkim-Darjeeling and found extensive loss of river-side forests and huge amounts of sediment accumulation in the dam-created reservoirs. Our studies indicate that both the dam reservoirs will have sediment fill-up in 70-90% of the reservoir areas, creating shallow wetland-like and sedimentary features in what would have been a white-water river valley within the next 10-15 years.
The rapid increase of hillslope failure and local landslide disasters are already being felt, with dozens of small and large landslides being reported in the rainy season every year, with many causing fatalities and rampant property damage. Additionally, changes in fish population, forest types, and huge changes in the micro-climate of valley habitations are also being reported which affect the life and well-being of the local populations, as well as widespread ecological issues.
In the last two years (2020-22) alone more than 60 scientific journal articles have reported the aggravation of landslide risks in the region. The lived experience of the people and the reporting of actual landslides affecting the habitations and connectivity, and the future of the road lifeline of Sikkim, the National Highway 10, is reported almost daily in the local press and citizen science groups like Save the Hills, Kalimpong (Hazard Alert group) with detailed descriptions of death, damage and daily tribulations and almost ongoing issue during the monsoon season.
The physical damage to the Teesta valley is well illustrated by the huge amounts of water released in monsoons causing erosion of hills below the Kalijhora Dam, and in the almost daily landslips and subsidence of NH-10 reported.
Given the potential loss of operational efficiency of dams due to landscape and climatological changes, and the associated loss of ecological services it is imperative that we pay more attention and thought to build such short-term gain infrastructure in the country.
Also, the low price, relatively smaller environmental footprint and relative reversibility of land use changes offered by other renewable energy generation & storage modes like solar or wind power combined with battery or gravitational storage – is possibly better use of both available capital and natural resources compared to hydroelectric dams in venerable ecosystems like the Sikkim-Darjeeling Himalaya. The governments of the day need to rethink energy generation, livelihoods and provincial revenue generation based on these studies.
The author is affiliated with the Ashoka Trust for Research in Ecology and the Environment, Gangtok.
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