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This is the eighth story in a series of articles launched by Astral Pipes and Nature inFocus to create awareness about the ongoing water crisis and to encourage necessary action to address it.

When I first became aware of Shishir Rao’s work, I also learned about the big problems of small dams. Till then, like many of us, I imagined dams to be massive structures that dissect large rivers. I never thought that they could be small structures that cut through relatively smaller rivers, high up in the Western Ghats. An engineer-turned-ecologist, Rao presented his research at the Moving Waters Film Festival in Bangalore, where he rattled off fact after fact about Small Hydropower Projects (SHPs) and proved why they might not be as clean and green as they are made out to be. I sat in the audience while he spoke, enraptured and hyper-aware of how far removed we are from man-made ecological problems that are created to solve our water supply issues. We remain blissfully unaware, even though we make up a large part of the ‘demand’. I returned from his talk and swore to learn more about what is happening to our water sources, at their source.

Shishir Rao studies river ecology in the Western Ghats. His primary focus is on understanding the impacts of flow alteration on river biodiversity. He has a Master’s degree in wildlife biology and conservation from the NCBS- CWS/WCS-India Master’s program and is currently pursuing his PhD in Integrative Conservation (ICON) and Ecology in the University of Georgia, Athens, USA. Be it assessment of river flow regimes, water quality and stream habitat assessments, sampling freshwater fish or marine overfishing, Rao can help you deconstruct facts and derive the hows and whys. Over emails and direct messages, we had a chat about the current state of SHPs in India and the way forward. 

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Shishir Rao studies river ecology in the Western Ghats. He is currently pursuing his PhD in Integrative Conservation (ICON) and Ecology in the University of Georgia, Athens, USA. Photograph: Anisha Jayadevan

We often hear of engineering graduates choosing completely different career paths later in life. How did this switch from engineering to ecology come about for you? 

I am fortunate to have had the opportunity to travel widely in the Western Ghats, volunteer/intern with wildlife conservation NGOs, and receive guidance from experienced conservation biologists and practitioners, some of whom used to be engineers themselves. I figured that my curiosity about the natural world and concern for nature and nature-dependent human communities could be put to good use by pursuing a career in ecology and conservation. Having an engineering background and professional experience equipped me with problem-solving skills, not to mention a small saving which cushioned me from the uncertainties of a career switch.

Why rivers? What are the challenges in studying them, both, at a larger landscape level and up close at a micro level?

I grew up curious about rivers, thanks to time spent in the coastal and Malenadu region of Karnataka. I study rivers because I am absolutely fascinated by the complexity of rivers and the diversity of life they support, both human and otherwise. At the same time, understanding how rivers work is important not just from a biodiversity conservation perspective but also for sustaining river-dependent livelihoods and maintaining water security for future generations. 

Rivers are challenging to study because they are complex and dynamic – think of it as an intricate web or a network that is constantly moving water, nutrients and sediments while interacting with surrounding landscapes as they flow. Also, rivers constantly change either in response to natural reasons such as seasonal change in rainfall or due to human influences such as construction of a dam or to both. From a social perspective, complexity arises due to the diverse ways in which people value rivers – as a resource to be harnessed for water security and hydropower, as a life-line which sustains biodiversity and provides livelihoods, or as a spiritual entity, to name a few.

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A free-flowing river in the Western Ghats with lush riparian vegetation. These riparian areas are important wildlife corridors for elephants and other animals. Photograph: Shishir Rao

Generally, complexity increases with the scale at which you study rivers because of increasing catchment size. For example, a stream in high elevation Western Ghats will have a small catchment – a few square kilometres likely dominated by sholas and tropical evergreen forests. At lower elevations, a river’s catchment is much bigger and includes several tributaries. The catchment may include built-up areas and agriculture. So, in larger catchments, many variables matter – urbanisation, agriculture, pollution from industries, multiple dams and diversions to name a few. Also, at larger scales, the values of human-associated conflicts intensify. For example, if an upstream dam diverts water, change in water quality and availability will have an impact on downstream users at the coast who rely on the same water for agriculture, drinking and for religious uses. 

Can you give us a quick introduction to Small Hydropower Projects (SHPs)? How are they different from dams? Is the energy from SHPs really green, clean and renewable as claimed? 

In India, Small Hydropower Projects (SHPs) are hydropower projects that produce <25 MW of power. In India, or at least in the Western Ghats, SHPs constitute a dam and a diversion canal which often runs up to several kilometres from the dam to a turbine situated downstream. The diversion results in a dewatered stretch with little or no water. The dam impounds the water and creates a reservoir from which the water is fed to a turbine via the diversion canal. After electricity is generated, water is released back into the river. The release of water causes unnatural fluctuation in water levels because the diversion canal essentially causes a short circuit by suddenly releasing impounded water from the reservoir back into the river. The release cycle can occur anywhere between 4-5 times a day to once in 3-4 days, depending on seasonal water availability. In some cases, electricity generation is timed to match maximum demand. 

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What a reservoir looks like when the SHP operations stop in late summer – the reservoir gates are open, so there is no water. What you see in the image are sediments trapped in the reservoir. Photograph: Shishir Rao

SHPs in India are not really different from large hydropower dams, except that they are built on smaller rivers, produce less power, have dams of lower height and are therefore smaller reservoirs. Most SHPs are well suited to tropical, mountainous regions like the Western Ghats because steep gradients add more potential energy to the impounded water and high rainfall fills up the dams faster.

A small dam on a smaller river will definitely have a lesser impact compared to a large dam on a large river. But this reasoning is flawed. Ideally, the impact should be scaled relative to the size of the river, in which case, SHPs can have as much of an impact as large dams or more.

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The same reservoir from the picture above, but when it is full. This is how reservoirs submerge large tracts of forest land and trap all the sediments. Like flowing water, it is important that sediments also keep moving in the river since they carry nutrients. Some species of fish even lay eggs in sediments. But when the reservoir traps the sediments, the stretches of  the river downstream are starved of sediments and nutrients. Photograph: Shishir Rao

Are there any examples of where SHPs have been able to solve the problems they were built to fix?

SHPs come in many varieties depending on their storage and diversion structures. A SHP without storage i.e. without a dam and without a diversion structure is called a run-of-the-river SHP. These are likely to have the least environmental impact compared to other designs. I can only think of community-owned, carefully designed micro hydel projects in the 5-20 KW range, which were found to be sustainable with negligible environmental impacts.

What is the ecological cost of SHPs? Can we really afford it?

Most SHPs are constructed in mountainous regions that are rich in biodiversity. SHPs have significant ecological impacts. Due to the diversion of water, several kilometres of the river dry up with serious consequences for aquatic and riparian biodiversity. The fluctuating water levels threaten sensitive and endemic species. The dam itself is an obstruction for migratory species. And, these impacts are heightened in summer when SHP operation exacerbates water stress for aquatic life. In the Western Ghats, towards peak summer, SHPs stop operation due to low water availability and open the dam gates. During this period, the sediments and silt trapped in the reservoir are directly released downstream often suffocating fish to death.

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A large area of the forest was cleared to make place for this SHP, which is under construction. Photograph: Shishir Rao

So, with these projects altering the natural course of rivers, the impacts on the freshwater fauna and riparian flora must be irreversible, right?

I agree. Our research suggests that sensitive and endemic species are taking a hit while other hardy and non-native taxa seem to dominate in stretches of water impacted by SHPs. Unless SHPs operate such that they release water for environmental needs, it is likely that the impacts are irreversible. If dams are operated in a way that they mimic ecologically important parts of the river’s flow, such as the peak monsoon rain or lower water levels during the dry season, they may restore the river’s ecology. But, any mitigation measure which involves a change in design will also most likely reduce the power generating capacity of SHPs. Also, research in the Western Ghats has shown that impacts of dams reduce downstream if there are other free flowing tributaries. So, recovery is likely if we do not dam every tributary.

You have been studying freshwater fish ecology in the Western Ghats. We see very little focus on these lesser-known species in popular media, and in comparison, there is this excessive focus on the research of the region's flagship mammal species. Does this bother you or hamper your work? 

It is true that less charismatic species receive little attention. In fact, at first, our research received relatively little public attention when we said that SHPs have significant impacts on hydrology, water quality and fish diversity. But, when we said that SHP operation might exacerbate human-elephant conflict, public concern was significant. 

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 A freshwater eel, Anguilla bengalensis, which usually lives at the bottom of the river, in between rocks. The photograph was shot late in summer, downstream of an SHP, which had stopped operation and opened the dam gates. The trapped sediments were released from the dam, and it filled up the river sections immediately below, plugging the crevices and flushing out the fish. Photograph: Suman Jumani

It does not really bother me because it is what it is – people care more when they can connect the dots and relate environmental impact to their own well-being. Therefore, it is very important to communicate the science to the public in such a way that they can see how they or future generations stand to be impacted by environmental degradation .

But yes, it does hamper research focused on less-charismatic taxa because of fewer funding opportunities and public support. 

Your research on the impacts of SHPs on human-elephant conflict are eye-opening. How did your research team come across this trend? 

An important component of our research was to understand the perception of local communities towards SHPs. We expected the SHPs to have some kind of impact on elephants because we knew that elephants relied on these streams for water and on the riparian vegetation for forage. During social surveys, we asked locals if they experienced elephant conflict, and if they did, we wanted to know when the conflict started. We found a surprising trend – human-elephant conflict in villages neighbouring SHPs became noticeable around the time the first SHP was commissioned, and the conflicts spiked every time a subsequent SHP was commissioned after the first. To illustrate, prior to the construction of SHPs, between 1999 and 2004, the forest department received 248 claims arising due to losses by man-elephant conflicts. After the SHPs were installed, between the years 2005 and 2013, the number of conflicts shot up to 2,030. Elephants likely came into contact with neighbouring villages because their foraging and movement were impeded by dams and canals. 

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An aerial view of an SHP in the Western Ghats. Photograph: Kalyan Varma

Your research team has also studied the social benefits and impacts of SHPs. Do they really manage to create sustainable employment for local residents? How do they impact the indigenous people in the region?

Our research indicates that SHPs in the Sakleshpur region barely create any local employment. In fact, many villagers were not even informed that SHPs will be constructed in their backyard. This is because SHPs are not required to conduct a public hearing before being commissioned. Although, on paper, SHPs claim to provide local employment, most jobs given to villagers are temporary and during construction only. Our social surveys suggest that local villagers perceive SHPs as either not beneficial or sometimes even harmful because SHPs restrict their access to rivers and reduce fish abundance. Similar results have been documented in Himachal Pradesh too. 

The politically-sensitive and mega-budget Yettinahole Project seems to be here to stay, with even the Supreme Court okaying it. We don't seem at all interested in learning from our past mistakes, do we?

True. The Yettinahole project is nothing short of a disaster. It was proposed as a project for drinking water supply to the arid regions of Karnataka. As per law, drinking water projects do not need environmental impact assessments. But, any large dam, regardless of whether it is diverting water for drinking water supply or hydropower, has serious impacts on the rivers and the adjoining forests, especially if it is built in a biodiverse landscape. Ecological issues aside, there are several other glaring issues:

  • Questions have been raised on whether enough water is available in the region as claimed by project proponents.
  • Were other alternatives considered to resolve the drinking water issue in water-scarce regions, including local measures such as wetland creation and improving water-use efficiency?
  • The city of Mangaluru has recently experienced severe water scarcity. Projects like the Yettinahole diversion are very likely to impact water security of regions downstream of the dams. The concerns of downstream communities are still unheard by Yettinahole project proponents.
  • The Yettinahole project is being built on rivers which have SHPs downstream. The cumulative impact of large scale water diversion and hydropower generation is likely to severely impact the ecology of the place.
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"Given how unpredictable our monsoon has become, how can a project like Yettinahole, which is intended to capture and divert monsoon rainfall guarantee reliable outcomes?" Site of the Yettinahole Project. Photograph: Shishir Rao

World over, large river infrastructure projects have come under intense criticism for their long-lasting hydrological, ecological and socio-ecological impacts. But we somehow seem to be oblivious to this fact. We live in an era of global warming and climate crisis. Given how unpredictable our monsoon has become, how can a project like Yettinahole, which is intended to capture and divert monsoon rainfall guarantee reliable outcomes? We desperately need a revamp to our very approach to water management. Currently, it is one of attempting to solve a problem by creating two more elsewhere. 

If environmental impact assessments are carried out accurately, and SHPs are planned and executed in time – both big IFs – do you think they might be a good solution? 

They might be. The question is not about whether we need SHPs or not but of how many and where? SHPs in India are being commissioned recklessly. Karnataka alone has nearly 14 % of the SHPs and contributes to nearly 28% of electricity generated through SHPs. Moreover, there are serious concerns over regulatory policies for SHPs. There are cases where two SHPs with production capacities slightly less than 25 MW were passed off as separate projects when in reality it was one project with nearly 50 MW capacity. In many river basins, multiple SHPs are commissioned within a few kilometers of each other. If SHPs are to be clean and green, as they claim to be, we need careful environmental impact assessments which consider the cumulative impact of new and existing SHPs. Local communities should have a larger say in whether they want SHPs in their backyard. More importantly, defining whether a project is small based on power generation capacity is misleading. Lastly, a 25 MW project can have a dam of height as low as 5 meters or up to 30 meters depending on the location. Therefore, height of the dam or area of reservoir is a better metric of environmental impact than power capacity. 

A short film by researcher Suman Jumani on the socio-ecological impacts of SHPs

How can the citizens of the country help? What measures should they take to be aware of how water sources are being affected?

I could say that rainwater harvesting and being water-efficient and water-conscious are useful actions that the citizens can take. But I believe that we need our governments to act much more than individual contributions. India is already the largest groundwater exploiter in the world and the country with the third-highest number of dams in the world. If we have to create water security, our water governance urgently needs to depart from an engineering-based, supply-demand-based approach to water management and embrace the fact that rivers are complex, dynamic and living ecosystems which provide valuable ecosystem services. Our solutions to water problems need inputs from diverse disciplines, including ecologists and social scientists and not just from economists and engineers. At the same time, local communities need to be empowered to make judicious water decisions by facilitating a bottom-up approach to water management rather than top-down.


Jumani, Suman, Shishir Rao, Nachiket Kelkar, Siddarth Machado, Jagdish Krishnaswamy, and Srinivas Vaidyanathan. 2018. “Fish Community Responses to Stream Flow Alterations and Habitat Modifications by Small Hydropower Projects in the Western Ghats Biodiversity Hotspot, India.” Aquatic Conservation: Marine and Freshwater Ecosystems, 1–15.

Jumani, Suman, Shishir Rao, Siddarth Machado, and Anup Prakash. 2017. “Big Concerns with Small Projects: Evaluating the Socio-Ecological Impacts of Small Hydropower Projects in India.” Ambio 46(4): 500–511.