Bihar · Dams · Ganga · Himalayas · Interlinking of RIvers

Dams, Fish and Fishing Communities of the Ganga: Glimpses of the Gangetic Fisheries Primer

Some highlights from SANDRP’s latest Publication on Riverine Fisheries of the Ganga

The government is discussing Ganga not only as ‘Ganga Mata’, but also as a ‘navigational corridor’ with plans to build barrages after every 100 kilometers with funding from World Bank. At her origin, hundreds of hydropower dams are changing the ecological character of the Ganga. However, as a rich ecosystem, the Ganga also supports  about 10-13 million riverine fisherfolk and about 300 freshwater fish species! Riverine fisheries have been a blind spot in Independent India, despite the fact that they provide nutritional and livelihood security to millions of people.In the post independence water management discourse, river has been equated to water and water to irrigation, water supply, and hydro power. The profound impacts of irrigation, water supply and hydropower dams on sectors like riverine fisheries have been entirely ignored.

Nachiket Kelkar looks at the status of riverine fisheries and fisher communities in the Gangetic Basin of India and highlights the devastating impacts of dams, barrages and water abstractions on this. Nachiket’s study on Gangetic Fisheries is based on long term engagement with fisher communities in the basin as well as robust scientific studies.

SANDRP has published this work in the form of a Primer which will soon be available online. What follows are some glimpses from the Primer. Please write to us if you are interested in receiving a full soft copy of the Primer.



Riverine fisheries of the Gangetic basin support one of the largest fishing populations of the world. However, its fish resources are rapidly declining due to large dams, barrages and hydropower projects, severely altered river flows, fragmentation of hydrological connectivity between rivers and wetlands, alarming levels of pollution, riverfront encroachment, rampant sand mining and unregulated overexploitation of fish resources.

Across its range, the fisheries show indications of economic unviability and ecological collapse, with violent social conflicts as an outcome of the contest over scarce and declining resources as well as politics and access. A major factor behind the serious fisheries-related problems is severe alteration of river flow volume and seasonal dynamics by large dams, barrages and hydropower projects. The state of river fisheries directly indicates the declining biophysical, ecological and social integrity of the river basin. The existing in-river fisheries contribute merely about 10% of the overall inland fish production. Even this production is highly unsustainable today and has all the indicators of serious levels of overfishing. For instance, river fisheries in Bihar now even glean small-sized fish fry for markets in northern West Bengal (Siliguri) and Assam, where eating small fish is a delicacy (F.pers.comm).

To understand the situation in Gangetic Basin clearly, a detailed, large-scale interview survey was conducted by the author in 2012 across 372 fishers in 59 fisher groups spread over 17 rivers in 5 north Indian states. The survey objective was to document perceptions of traditional fishing communities about issues and problems in fishing in the Gangetic basin. Of the respondents, c. 90% singled out “large dams and poor river flows” as the main causes for a near-total decline in fisheries and fish resources over the past 4 decades. About 90% people mentioned low water availability and stoppage of fish migratory routes by large dams as the main cause for fish declines. Almost 45% (from eastern and northern UP, and Bihar) singled out the Farakka barrage as the main problem.

The Sone River in the dry season. Poor river flows released by dams and barrages have serious implications on fisher livelihoods. Photo: © Subhasis Dey.
The Sone River in the dry season. Poor river flows released by dams and barrages have serious implications on fisher livelihoods. Photo: © Subhasis Dey.

The Canvas of Gangetic River Fisheries
The Ganga  River, from her headwaters to the delta, along with hundreds of her tributaries drains an area of approx. 0.9_1 million km2 across northern and eastern India, flowing through 10 states in India and also in Nepal and Bangladesh. These rivers form one of the largest alluvial mega-fan regions of the world, and deliver huge quantities of sediment from the Himalayas to the northern Indian plains and to the Bay of Bengal in the Indian Ocean. The Gangetic floodplains shape not only landforms but also complex human cultures that attempt to stabilize themselves and adapt to the constantly changing riverine forces. Biodiversity, hydrology, geomorphology and social dynamics influence each other through constant interaction and multiple feedback mechanisms.

The major rivers of the Gangetic Basin (Based on ‘hydro1k-rivers-Asia.dbf’).
The major rivers of the Gangetic Basin (Based on ‘hydro1k-rivers-Asia.dbf’).

The dynamic balance of these factors triggers opportunities for spawning, reproduction, population dynamics and viability, migration and movement of freshwater species, including fishes, river dolphins, otters, crocodilians, turtles, invertebrates as well as terrestrial biodiversity.

In floodplain rivers, as floodwaters recede post-monsoon, fishers record the highest catches in October and November, as large post-breeding and migrating adult fishes (e.g. major carps, clupeids, mullet) become catchable. Winters, from December to early February, generally record low catches because many fish show slowed behavior and limited movement. But in spring fisheries of minor carps and catfishes record high production. With water levels reducing, fishes become more concentrated in specific river habitats like deep pools, where they are easy to fish. Summer fish catch biomass is also reasonably good due to the overall low water availability.

In the Gangetic basin, fisheries are practiced in a range of diverse freshwater habitats including natural and man-made, lentic (stagnant water) and lotic (flowing water) ecosystems. Natural freshwater areas include large floodplain rivers, non-perennial rivers, perennial and seasonal streams, cold-water rivers and streams, glacial lakes, estuaries, tidal rivers, floodplain wetlands, oxbow lakes, grassland swamps and marshes. Manmade habitats include dug or built-up wetlands, ponds, man-made reservoirs, dam reservoirs and canals. To the fisher, flow velocity, depth profile, substrate type, vegetation structure, current patterns and habitat stability are key indicators for fishing effort allocation and logistical decisions.

Fish Diversity in the Gangetic Basin
The overall species pool of the Gangetic fish assemblage is estimated at around 300 species (53+ families, 150+ genera; 250 species). The floodplain fisheries are dominated by major and minor carps (Cyprinidae), catfishes (Siluriformes: 6-7 families), Clupeidae, Notopteridae and a mix of many other families. Major carps and the Clupeid fish, Hilsa (Tenualosa ilisha) and some large catfishes form the most valued catches across most parts of the Gangetic floodplains.
Major carps, the most preferred freshwater food fishes, include species like Catla, Rohu, Mrigal, Mahseer etc. exhibit potamodromous (along freshwater upstream-downstream gradients) migration. Though these fishes have suffered serious declines due to overfishing, pollution and dams, they have been mass-produced through artificial rearing in pond aquaculture. Farmed large carps form the major proportion of fish eaten anywhere in India today. In wild fisheries, catfishes come lower in the preference order, but with the decline of carps, medium and small catfishes have become the main fishing targets. Further, as most catfishes are sedentary and do not show long-distance movements, the fisheries have completely switched from carp- to catfish-targeting fisheries. Other deep-bodied, highly sought after fishes include the Chitala and Notopterus, or the featherfishes, and mullet.

Various fish species in Ganga Basin. Refer to the Primer for more information.
Various fish species in Ganga Basin. Refer to the Primer for more information.

The estuarine fishery in the Hooghly and Sunderbans tidal rivers in West Bengal is dominated by shellfish (prawns, mud crabs and shrimp), Clupeidae and Engraulidae, Sciaenidae, catfishes of the Ariidae and a far more diverse set of families compared to truly inland fisheries. Other important components of the commercial fisheries include 5-6 species of shellfishes (mainly prawn and shrimp).

Coldwater fisheries specialize on large-bodied, rapids-loving potamodromous migrant fishes such as Mahseer and Snow Trout. These fishes are of high commercial importance and are in high demand by professional sport fishers and anglers, apart from being highly prized as food locally. Mahseer in particular, have recently led to the opening of new markets of luxury wildlife tourism that is based on angling and recreation in the Western Himalaya.

Dam reservoir fisheries are almost entirely based on managed stocking and breeding of commercial fishes in hatcheries, of major carps Catla, Rohu and Mrigal, catfishes like Pangasiodon, and minor catfishes. The state of river fisheries in the Gangetic basin has been affected over the last few decades by several threats described in the next section.

Dams and Riverine Fisheries in India Fisheries across India have been severely affected by dams, flow regulation and associated human impacts, which have substantially altered ecological requirements of fisheries and biodiversity together. If one clinically investigated the fisheries’ decline, they would find it to coincide with the period of maximum dam building (1970s-80s) in India. Most commercially valuable fish species, especially major carps and Hilsa, have shown population-level collapse and even commercial extinction over large inland waters. Reduction in harvested fish size-class distributions, a classical indicator of overexploitation by fisheries, points to poor fish recruitment and adult survival, which may be further brought down by flow regulation by dams. Dams have acted as the major factor of disruption by blocking migratory routes of upriver or estuarine spawning fishes such as Hilsa and Anguilla eels. Dams have also caused loss of genetic connectivity between fish populations, most notably seen in major carp stocks. Erratic water releases, nutrient and sediment trapping behind dams and barrages, failure of breeding in carp and catfish species due to siltation, erosion, poor water availability, modified thermal regimes required for breeding (increase in temperatures due to low river depth/flow), and exceptional levels of hazardous pollution (again, magnified due to the poor flows reducing dilution capacity of river water), are other fallouts that adversely affect fisheries. The fact that there is just not enough water in the river must form the bottom line of any causal investigation of riverine fisheries. Lack of appropriate policy measures and pollution receive dominant mention as threats to fisheries by government research agencies, but they are mere outcomes of much larger shifted baselines because of dams. Dams, barrages and hydropower projects through flow regulation have increased uncertainty about fishing and driven fishing to desperate levels: fishers often resort to destructive practices, or even worse, exit the fishery altogether. Such exit does not solve the problem of existing fisher folk: water is critical to sustaining not just fisheries but the river and the people dependent on it. Detailed understanding of the lives of fishing communities of the Ganges is therefore critical.

Ganga made completely dry at Haridwar by the Bhimgouda barrage Photo: SANDRP.
Ganga made completely dry at Haridwar by the Bhimgouda barrage Photo: SANDRP.

Fisher communities in Ganga: Around 10-13 million people in the Gangetic floodplains are estimated to be dependent on fish resources for their livelihoods, directly or indirectly. However, accurate estimates of active traditional and non-traditional fisher populations are still wanting. It is important for any discussion on fishing communities to clearly separate traditional fishing communities from ‘non-traditional fishers’, who may be practically from any other local community and with the possession of other livelihood options, but also opportunistic fishing, due to unrestricted access to imported nets and gear available in markets to anyone. Traditional fishing communities were always the craftsmen of their own nets and gear, and also possess remarkable ecological knowledge about rivers, fish and biodiversity, their breeding biology, ecology, seasonality, and distribution. Of course, with the degradation of fisheries throughout the Gangetic plains, the traditional knowledge and practices of fishing are eroding fast. Hence such knowledge needs to be documented well, especially from old fishers with whom it still persists, to identify historical baselines of river fisheries with a different, past ecological reference (pers.obs.; F.pers.comm).
Traditional fishing communities today form a highly marginalized, politically unorganized and socio-economically impoverished people. Caste discriminations and political history form the chief reasons for their poverty and subjugation over centuries of fishworking. But the present condition of rivers does not seem to offer hope to any improvement in their economic position unless and until there is collective voicing of their concerns, especially against large-scale water engineering projects that threaten their livelihoods.

Author in discussions with fishers
Author in discussions with fishers

Their livelihoods, one may argue, confined them to the river’s water, albeit the fact that they never owned the waters legally. However, they always have stated cultural claims of temporally confined territory, following their foraging preferences and site usage. But depending on the nature of the river’s hydrological dynamics, there may be variable maintenance of fixed ‘territories’ by fishers adopting a roving mode of fishing, and neither legal nor cultural claims can be reconciled to a level that the conflicting parties can reach mutually. With regards to their economic viability and status, a large proportion of the traditional fishworkers fall Below the Poverty Line (BPL), and are recorded as Economically Backward Castes, and also have been assigned the status of Scheduled Castes. Annual incomes from fishing alone, according to the few estimates available, range from INR 25,000/- to INR 50,000/- (pers.obs., F.pers.comm.).

Large dams, flow regulation and Gangetic basin fisheries : The singular key problem of fisheries today is that it lacks water in the dry-season, because of flow regulation by dams, barrages and hydropower projects. More water flow releases are needed for the protection of riverine fisheries in the Gangetic basin. Widespread river habitat degradation, industrial, agricultural and domestic pollution, altered flows and modification of sediment and nutrient fluxes by dam projects, and resource overexploitation (by fisheries, agriculture or industry) have had major consequences for the unique biodiversity and fisheries of floodplain rivers across Asia. Obstruction and fragmentation of river flow, habitat destruction, accelerated erosion and siltation, long-distance water diversions (involving huge amount of transmission losses and waste) and poor flow releases are the major direct threats of dam-canal systems in the Gangetic plains.

Flow volume problems: Lower-than-minimum flows have been consistently recorded across the Ganga, Yamuna, Chambal, Kosi, Sone, Ken, Betwa, Ghaghra and Gandak rivers. Along with these large rivers, almost all others (Rapti, Baghmati, Mahananda, Teesta, Kamla, Burhi Gandak, Punpun, Gomti and others) have been highly regulated64,69. The reduction of freshwater discharge reaching the Sunderbans because of the Farakka barrage has led to high degree saline ingress throughout the estuary, causing die-offs of considerably large tracts of mangroves and aquatic vegetation, as well as severe losses to the upstream fishery. Downstream, fishing practices suited to brackish and fresh waters now have to adapt to saline intrusion into the estuary’s waters. Globally, fragmentation and flow regulation have caused the most severe impacts through drastic alterations to riverine biota and ecology. Low flows and fragmented connectivity of river channels lead inevitably to fish population declines and breeding failure. Over time, dams have probably led to genetic isolation of fish populations as well as river dolphin / crocodile populations, destruction of fish breeding habitats and spawning triggers and loss of valuable wild fish germplasm. These losses are so large in their ecological value and opportunity costs that they cannot be recovered with artificial fish culture techniques or hatcheries.

Aggravation of pollution effects: The Ganges basin is one of the most polluted large river basins in Asia, especially with regards to domestic sewage and agricultural runoff. Poor flows reduce the dilution and self-purification capacity of river water to reduce concentration of pollutants and local impacts on fishes. . Agricultural fertilizers (organophosphates, organochlorines, nitrates etc.), heavy metal pollution from industrial effluents, thermal power plants, oil refineries, distilleries and tanneries, and nitrogen-rich sewage, waste-water and non-biodegradable substances such as plastics, mercury, radioactive compounds and hospital wastes can cause fish kills or even worse, lead to high levels of toxicity in tissues. Pollution problems are especially acute in highly regulated river reaches, especially around Delhi (Yamuna River), and the Gomti at Lucknow, Yamuna until Panchnada in UP and Ganga River at Kanpur, Allahabad, Varanasi, Patna, Barauni, Bhagalpur and Farakka.

Polluted Ganga at Allahabad Photo: National Geographic
Polluted Ganga at Allahabad Photo: National Geographic

Siltation in dam reservoirs and barrage gates: Excessive siltation in the Ghaghra barrage has led to, as per local fishers, breeding failure in Labeo angra (Ghewri), a preferred spring-fisheries target in the region. The fishers claimed that over the past 5 years they have not captured a single fish with eggs inside it, and also added that catches have plummeted heavily (F.pers.comm). Siltation of gravel/sediment in reservoir or storage zones is a problem of huge magnitude for fisheries, especially through breeding failure. Accumulated silt in reservoirs is estimated to be so high (in tens of meters height) that it cannot even be easily flushed out, and leads to nearly 60-90% reductions in sediment fluxes of rivers in monsoon and non-monsooon seasons. Siltation adds to obstruction of flow release through barrage gates. In the Farakka barrage, sediment load accumulation is leading to breakage of gates every year, adding to maintenance costs.

Habitat destruction and alteration of erosion-deposition dynamics: Soil erosion by erratic and sudden releases before floods can potentially lead to alteration and destruction of fish breeding habitats and stock depression. Changes in depth and flow velocity lead to fish not being able to receive natural physiological cues for movement and spawning that are otherwise provided by variability in discharge. Flow alteration also alters hydrological connectivity and sediment transport with wetlands and confluence channels during flooding. As a result these productive breeding habitats often become unavailable for catfishes and carps. These factors together become a problem for pre-settlement fish juveniles and recruits, which move into the main channels.

Threats to cold-water and foothills fisheries from Hydropower Dams: Overall, despite their projected low impact situation, hydropower projects can have serious large-scale effects on mountain streams as well as rivers downstream. Globally, despite mitigation measures in hydropower constructions, fish migration and development have largely been deemed as failures. In India, hydropower projects, especially run-of-river projects in higher altitudes, often have disastrous effects on natural thermal regimes, cause sediment blockages and perturb natural flow variability at diurnal timescales through releases varying across several orders of magnitude. These changes severely affect not just breeding and migration in higher-altitude cold-water fisheries of snow trout and Mahseer in Himachal, Sikkim and Uttarakhand, but also downstream fisheries of catfish and carps in the foothills and plains due to altered flows. Their cumulative downstream impact can also potentially risk fisheries-based uses of river water without being exposed to the risk of sudden flow releases every day.

Globally, through extreme perturbation of natural flow dynamics, dams have homogenized and altered many crucial river-floodplain processes, and have had disastrous impacts on biodiversity and fisheries. There is an urgent need to ensure ecologically necessary, adequate and natural flow regimes in all rivers of the Gangetic basin. The current water scarcity is so severe that projects such as river interlinking, apart from their ridiculous proposed costs, are simply impossible to conceive of, water itself being the limitation. There is no doubt that further water developments will prove disastrous for a whole section of people and their livelihoods, and must be scrapped. Rivers that need urgent attention in this respect are the Chambal, Yamuna, Ken, Betwa, Alaknanda, Bhagirathi, Mandakini, Sone, Damodar, the Ganges at Farakka and Allahabad, Sharada, Ghaghra and all other rivers especially in Uttar Pradesh, Uttarakhand, Madhya Pradesh and Bihar0. Run-of-river hydropower projects, flow diversions and links, pumped irrigation, embankments, agricultural intensification, groundwater depletion and sand mining are highly destructive threats that will affect not just fisheries but the whole social fabric of river users in the near future.

Despite the demonstrated folly of not allowing rivers to flow from headwaters to estuaries and deltas, engineers, technocrats and politicians talk of “rivers flowing wastefully into the sea”. This statement would imply that the thousands of species and millions of fisher livelihoods that need flowing water in rivers are of no value to the state policy on water resource development. Such statements are ignoring important societal needs and hence are evidently irresponsible.

No post dam-construction compensation schemes exist for fishers, who may lose their entire livelihood because of flow-regulation and loss of hydrological connectivity due to dams. Downstream fisher populations must be ideally compensated for the lost fishing catch and livelihood opportunity, but in general there has been scant attention towards the communities’ livelihoods (F.pers.comm). Downstream water allocations through on-ground consultations with fisher communities are urgently needed (F.pers.comm). In India, water resources development is so strongly irrigation-focused (and now strongly focused on industry and hydropower), that, in comparison, riverine fisheries are not even acknowledged as legitimate and in need of conservation and livelihood protection. These biases mean that only pond aquaculture receives any attention. If river conservation and development groups can actively work with fishing communities in order to develop an informed and aware constituency or interest group, fishers will gain political voice in making negotiations about water availability in river basins.

Fisherfolk of Ganga Photo: Gangapedia
Fisherfolk of Ganga Photo: Gangapedia

Fisheries incur ‘colossal losses’ every season due to irregularities in dam operations, and always fall severely short of demand. But now, through the boom of artificially managed pond aquaculture and wetland fishing especially in Andhra Pradesh and West Bengal, the nature of supply itself has radically changedThis boom has contributed to India becoming one of the largest producers of inland freshwater fish in the world. But such ranking hides a lot of miserable facts about river degradation. Although net production shows increases, the collapse of river fisheries that still support millions of poor people who don’t get access to aquaculture, get totally ignored under such swamping. This is why farmed fish in fish hatcheries can barely replace riverine fisheries despite the fact that they have cornered the attention of fisheries development.

The failure of river fisheries has led to large-scale outmigration for labour from the Indo-Gangetic plains (F.pers.comm.). This might be a significant contributor to the magnitude of labour-related migrations from the Gangetic plains, which has been a rising exodus. Today, fisher folk from Uttar Pradesh, Bihar and Bengal provide a large proportion (20-40%) of construction and manual labor force across India (F.pers.comm). Others who stay behind have to take to menial jobs such as rickshaw-pullers or servants (F.pers.comm; pers.obs). Some are forced to take to crime to be able to feed themselves and their families. These factors can weaken the social resilience of production systems and create poverty, disparity and community breakdown. It has been argued that ethnic conflicts between local Indian populations and illegally immigrated Bangladeshi refugees are linked to poor water releases from the Farakka barrage in West Bengal, to downstream floodplain reaches in Bangladesh.

Mitigation measures like Fish ladders and hatcheries
There is little existing research on the construction design, functioning and efficiency of fish ladders in tropical and subtropical large floodplain rivers. Across the tropics, monitoring studies on fish ladders do not show positive results. A handful of barrages in India have constructed fish ladders, but owing to numerous problems they have been largely a failure. These problems are all related to the extremely low discharge rates from the dams – as there is simply not enough water volume allocated for migrating fishes, which therefore cannot access the ladders and fish lifts. Other problems are linked to siltation in reservoirs and turbulence of flows near the fish passages. For instance, the Farakka fish lifts do not seem to have been of any help due to the extremely low outflow of the Ganga River from it, and the commercial extinction of the Hilsa fisheries both upstream and downstream is clear with an estimated 99.9% decline. Fish passes constructed at barrages on the Yamuna River (Hathnikund barrage) and the Ganga barrage at Haridwar have been monitored by CIFRI and the results suggest that they have had very low success for migration of cold-water species like the Golden Mahseer Tor putitora. Similar structures on the Beas River and Mahanadi River (Salandi dam, Orissa) have found to be ineffective in buffering the adverse impacts on fisheries production in these rivers. India has dominantly followed reservoir hatcheries development, and therefore consideration for effective fish ladders has always been low priority. However, as we have seen, hatcheries themselves bring about several problems for native fish populations – and are not an ecologically viable solution, despite being economically profitable to certain interests. Given the poor success of existing fish passages, it is important to consider modern designs in existing and proposed dams that are suited to the ecology of our own fishes. A whole body of interdisciplinary research – spanning engineering and ecology, is needed to address the significant gaps in our understanding of making fish passages work. We need to monitor existing examples well to assess reasons for their failure. Again, just the act of allowing higher dry-season flows and timely adequate releases in the river could be a far more effective strategy for fisheries improvement than other intensive technology-driven practices to enhance fisheries production (F.pers.comm)

River restoration and alternative livelihoods: Given the current state of riverine fisheries, there is an urgent need to consider possibilities for large-scale ecological restoration of rivers by modifying dam operations and improving ecological flows. Alongside restoration, it is crucial to consider alternative livelihoods to fishers, which regard their traditional knowledge and provide them with clearly defined user rights and responsibilities over management of wild-caught or cultured fish resources. Ecological restoration of all major and minor rivers in India needs to be undertaken urgently, to ensure ecologically adequate, naturally timed flow releases, consistent dry-season flow regimes, hydro-geomorphological habitat maintenance, flood maintenance and reduction in pollution. Dam re-operations to ensure adequate flows and variability in river discharge remain a neglected aspect of river management in most regions today. Flow restoration can lead to improved health, numbers and availability of native commercial carps and preponderance of larger fish sizes through improved juvenile recruitment, along with other advantages to surface hydrology and local groundwater availability. Large-scale scientific research and monitoring programs must be instituted to study the response of inland wild-capture fisheries and take further steps to mitigate local threats. Restoration also needs to involve stringent restrictions on release of untreated domestic and industrial effluent, especially in urban belts such as Kanpur, the National Capital Region of Delhi, Allahabad-Varanasi, Mathura-Agra, Lucknow in Uttar Pradesh; Patna, Barauni in Bihar and the Durgapur and Kolkata regions in West Bengal. Strict restrictions are needed on sand-mining, riverfront encroachment and embankment construction, especially in the Chambal, Ghaghra, Gandak, Baghmati, Rapti and Kosi Rivers. In this regard, more judicial interventions, such as seen recently in the case of sand-mining closures from river beds based on a review by the National Green Tribunal, are critical in reducing wanton and unregulated destruction of riverfronts, when implemented effectively. In terms of reducing the most direct impacts, there is a need to regulate fishing pressure and completely curb destructive fishing practices like dynamiting, use of mosquito-nets, beach seines, and gillnets below allowable mesh-sizes, poisoning, use of long-lines etc. Traditional fishers must be involved directly in monitoring and banning the use of destructive practices by the government monitoring agencies.

Finally, the quest for sustaining fisheries in the Ganga River basin in the long-term will require rethinking of current dominant paradigms to move towards ecological restoration of rivers, their biodiversity, as well as socially just, rights-based and equitable socio-political restoration of traditional fisher communities and fisheries management systems.

-Nachiket Kelkar

Ashoka Trust for Research in Ecology and the Environment, Srirampura Royal Enclave, Jakkur, Bangalore 560064, India. (The views expressed are of the author and do not belong to the institution where the author currently works)

Member, IUCN Cetacean Specialist Group, IUCN, Gland, Switzerland.



Twelve-point recommendation from traditional fisher communities for sustaining riverine fisheries and livelihoods in the Gangetic basin.

Rank Need Recommendations
1 Water Provide enough water, adequate natural flows in all rivers. Allow fish movements upriver, currently blocked by large dams and barrages. STOP new dams and mindless, high-cost, destructive and unsustainable engineering projects such as river interlinking.
2 Ban on destructive fishing practices Curb destructive practices of fishing, especially mosquito-netting, poisoning, dynamite-fishing, trawling and beach-seine netting everywhere.
3 Poverty alleviation and social security Fishers are in need of government dole or loans, technical know-how, permits and I-cards, housing, education and displacement packages. It is alleged that these benefits are hardly reaching them, although the allocations of funds reach farmers easily. Fishers need government security from criminals / mafia / anti-social elements / pirates that harass them and grab fish catch.
5 Define fisher rights and responsibilities Clearly define fishing use and access rights across all riverscapes, provide clear guidelines on multi-objective management of fisheries amidst other economic activities
6 Reduce pollution and mass fish-kills Urgent need to reduce the presently excessive river pollution, especially industrial but also domestic wastes.
7 Alternative livelihoods River fisheries are currently in a state of ecosystem-level decline or collapse. Trash fishes have become the most common catch, replacing many commercially viable carps and catfishes. People require alternative livelihoods in situ, to check problems related to migration and exodus to work as construction laborers or rickshaw-pullers. Community-based, cooperative pond carp-culture fisheries seem highly promising. Other alternative livelihoods include working with river management authorities, conservation agencies, ecotourism, agriculture etc.
8 Fishery co-operatives Focus on community-based management of river fisheries and help it develop in an ecologically friendly and sustainable manner. Replace the systems of private contracts and free-for-all fishing by power-equitable, social dignified resource-sharing arrangements
9 Ensure compliance of fishers towards biodiversity conservation and monitoring Needs to be ensured through continued monitoring of fishing activity and behavior, including by-catch or hunting of species. This will help safeguard endangered wild species such as gharial, turtles, river dolphins, birds etc. This can also help the spread of exotic food fishes that are rapidly invading our rivers (the worst examples are Tilapia species, Chinese and Common Carps, and more recently, Red-bellied Piranha.
10 Use of Food Security Act, Rural Labor Programs Can facilitate daily incomes by which fisheries losses could be offset; while also providing a solid community-level incentive to regulate and monitor fishing.
11 Restoration of native riverine fish communities Very important given the huge decline in native carp species of high commercial value. Fisheries need to protected not only by revival of stocks, facilitating better fish recruitment, but also by protecting fish breeding habitats from
12 Adaptive management of water tenure in fishing areas Owing to natural uncertainty linked to flow regimes and channel course changes, new flexible systems of tenure in fisheries are required. Such systems would fit in well with providing a clear definition to fishing rights in any riverine stretch.
Dams, Rivers & People

Dams, Rivers & People – December 2013-January 2014, Vol 11, Issue 11-12

The December 2013 – January 2014 edition of SANDRP’s magazine ‘Dams, River and People’ is now available online. This is the 11-12th issue of magazine in its 11th volume.  The contents magazine are mentioned in the list below. Packed with information on water, rivers, dams and environment, this issue covers matters at home in India as well in Bhutan, Nepal, Spain, Vietnam, United States of America and water dispute between India and Pakistan. The  magazine in pdf format is available here — Several of the articles are also available in SANDRP’s blog and they can be viewed just by clicking on the name in the list. Enjoy reading.



Page No
Is Environment just a political football for the NDA and UPA?   1
Muck dumping by damaged Vishnuprayag HEP in River 3
Possible explanation for Seti River flood of Nepal in May 2012 4
Visit to Fish ladder at Kurichu HEP in Bhutan 9
Court Order on India-Pak Kishanganga dispute on E-flows 14
Water Sector Review for India for 2013 18
Water Sector Review for North East India for 2013 20
Water Sector Review for Maharashtra for 2013 23
Notice to GVK project over damage to Uttarakhand town 28
Illegal Public Hearing of Lower Siang HEP Called Off 29
US Congress Opposes Financial Support for Large Dams 30
Dam Removal & Cancellations in Vietnam, Spain and US 31
Short film on Uttarakhand disaster: Flood Ravage and the Dams 32
Bhutan · Hydropower

Fish Ladder at Kurichhu Hydropower Project, Bhutan: Some thoughts

By Malika Virdi and Emmanuel Theophilus, Himal Prakriti

 While hydro-power is projected as clean energy, there is sufficient evidence to the contrary, on various counts. One of the major concerns about hydropower projects, is that the dams, whether they be impoundment dams or diversion dams (the latter going under the misleading euphemism nowadays of run-of-the-river structures), critically fragment a river. Regulation and release of water at extreme lows (often nil) and sudden releases apart, dams are an impassable barrier for migratory fish, progressively depleting populations past critical thresholds, eventually leaving rivers bereft of life. Dead rivers affect not only the freshwater aquatic realm, but also all terrestrial life dependent on rivers, including large human populations. The impacts are known to cascade down the entire river continuum down to the oceans. Not only does such river regulation have serious political implications in terms of equity and justice between proximate and faraway users, but far-reaching cultural repercussions as well.

Kurichhu HEP Photo: Druk Green
Kurichhu HEP Photo: Druk Green

In the on-going discourse on the large-scale build-up of hydro-power projects in the Himalaya, which will soon be the most densely dammed region on earth, one encounters proposed part-solutions, often billed as mitigation measures. Ofcourse, every attempt at addressing the serious problems created by hydropower projects is desirable and welcome. However, which of these actually mitigate or provide solutions to the problems created by hydro-power projects, and which of them only serve to provide camouflage from public gaze, or a cover of legitimacy for mandatory approvals, does require to be looked at more closely.

We have been hearing for long about fish passes of various designs constructed on hydro-power dams in the US and in Europe, to allow the passage of many species of migratory fish, to travel to their breeding grounds in distant mountain rivers. None of the numerous hydro-power projects under construction in Uttarakhand have incorporated any provision for the passage of seasonal migratory fish, and this is puzzling. How are hydro-power projects cleared on environmental grounds and approved despite their disastrous impact on fish movement and subsequently on fish populations?

One instance of a proposed mitigation measure is what was proposed by WAPCOS for NTPC’s Rupsiabagar-Khasiabara HEP in the Gori river basin where we live. While the project has recently been denied Forest Clearance for diversion of forest land for the specific dam-site, it had earlier managed to secure overall Environmental Clearance on the basis of proposed mitigation measures, and is being cited here as a case in point. Addressing the problem of creating a barrier for movement of migratory fish, WAPCOS proposed an entire fish breeding-and-stocking programme. The proposal was for setting up facilities for producing seed of snow trout (Schizothorax richardsonii) at a cost of Rs. 16.05 million, for periodically stocking 3 cm long fingerlings with 100 fingerlings per km of river, for 10 km upstream and downstream of the dam structure, for 5 years. Serious money that could even sound like a serious effort. Only, anyone living close to the river knows that the proposed dam-site itself, let alone 10 km above it, is entirely uninhabited by any fish whatsoever. This was clearly a ‘mitigation measure’ proposed only to obtain environmental clearance. It is another matter that even WAPCOS’s species fish-list for the river was just a wish-list.

In the context of addressing the problem of fish-passage, we were informed of a fish-ladder constructed by the NHPC for the Kurichhu HEP in Mongar in Bhutan, so we undertook to visit and see the fish ladder design, and to speak to the hydro-power company to understand how effective it was. The Kurichhu is a medium sized Himalayan river in Eastern Bhutan, forming the upper main-stem of the Manas river which originates in Tibet. Access to it by road is long and circuitous, and after a year of trying to get away for long enough to visit, we finally reached there on the cloudy afternoon of 11th January 2014. Prior permission had been sought for the visit through contacts in India, and we were received and shown around with rare grace and courtesy by officials of DrukGreen, the company running the hydro-power project after handover to it by the NHPC of India. The sight of the ladder was thrilling, and we were even permitted take photos of the fish ladder.

Fish Ladder at Kurichhu HEP Photo : Authors
Fish Ladder at Kurichhu HEP Photo : Authors


January is not the season for either upstream or downstream movement of fish in that zone, so we could not see fish movement in the ladder for ourselves. However, we gathered the following:

The dam is a 55 m high (from the foundation) concrete gravity dam located at an altitude of about 530 meters asl and is 285 meters across the beautiful, dark, blue-green Kurichhu river at Gyalpozhing. At full reservoir level 15.70 million m³ of water is impounded behind the dam. At the time of our visit, one of the four turbines was operational and there was a small release of water downstream of the dam. The fish ladder was in flow, releasing just 0.8 cumecs of water. The project authorities said that during such low-flows, this is the only flow from the dam, since there is no minimum flow required to be maintained by law in Bhutan. The ladder is a pool-and-weir type, with submerged orifices and centrally located notches.  A pool and weir design is one of the oldest styles of fish ladders. It uses a series of small dams and pools of regular length to create a long, sloping channel for fish to travel around the obstruction, in this case the dam. The channel acts as a fixed  lock to gradually step down the water level; and to head upstream, fish must either negotiate a slot, or jump over from box to box in the ladder.

The Kurichhu fish pass has a total of 98 baffles, each 1.5 m wide and 1.5 m deep, arranged at a distance of about 2.9 m. The total depth of each pool is 2 m. There are two exits (water entrances) to the fish pass, the lower exit placed 5 m lower than the other, to provide for flow at different draw-down levels. The vertical height between the water level of the ‘stilling basin’ (interesting name for a reservoir holding 15.7 million m³ of water) and the water entrance for fish from below the dam is 32 meters. To achieve this height, the fish-pass channel has to traverse a total distance of 320 m, leading to a slope of 1:10, and resulting in a drop in height per pool of 0.3-0.4 m. Quite impressive, except that the slot in the centre of each baffle does not exceed 25 cm in width. Clearly, no way for big fish, and Mahseer (Tor), the fish with the longest migration distance in this river, also happens to be the largest carp in the world.

We asked the project manager whether they know the fish ladder to be effective. He said that on a few occasions during the fish migration season, they had stopped the flow of water in the ladder and found some small fish in some of the drained pools. They did not know which species they were. We enquired whether there had been any systematic study of the efficacy of the fish ladder, in terms of comparing, with a baseline since commissioning the dam in 2002. Whether there was a change in species composition, or a significant change in upstream fish populations during this time? He replied that they had not.

Mahseer in Bhutan's Rivers. Photo with thanks from:
Mahseer in Bhutan’s Rivers. Photo with thanks from:

Discussion: It is understandable that project authorities in Bhutan were not familiar with names of fish species or other particularities, because people in Bhutan in general do not catch or eat fish. This could stem from Buddhist tradition, but also from funereal custom, where one of the traditional options is that the body of deceased adults is dismembered and consigned to the river for fish to consume.

On enquiring about any documentation with regard to the fish ladder design, they kindly shared a document titled ‘Feasibility Studies for fisheries development in Kurichhu reservoir, Bhutan’ prepared for NHPC, Faridabad, by CIFRI, Calcutta. While CIFRI has been hired by NHPC ostensibly for extending their expertise on fish, they could have spared us their use of tired narratives of ‘development’. It is clearly beyond their area of expertise. Prefacing their feasibility study on fish passes with statements such as “advancement of human civilization and distortion of natural habitat go hand in hand,” and “requirement of electricity is synonymous with the development of civilization”, and more, just exposes their fait accompli. We photographed relevant pages onsite, and along with discussions, have gathered the following:

Since every fish passage requires to be designed to cater to the specific behavioural propensities and physical capabilities of a particular set of fish species inhabiting the river in question, certain stretches of the river were sampled by CIFRI. The fish they caught can be grouped into three broad groups:

  • Snow trout, mahseers and minor carps: Schizothorax richardsonii. S. Progastus, Barbodes hexagonolepis, Labeo dolycheilus.
  • Loaches: Garra lyssorhinchus, G. gotyla,
  • Catfish: Glyptothorax coheni, G. brevipinnis, Pseudocheneis sulcatus.

CIFRI did not catch Tor during sampling, but during dam building many fish were caught by workers and staff from India, one 15 kg and another 20 kg fish near Kurizhampa bridge. Fish of this size cannot be Barbodes or Chocolate Mahseer, and seem to be Mahseer of the Tor genus (species tor or putitora).

The three functional categories of fish migration in general are: Reproductive (spawning) migration, feeding (trophic) migration and refuge migration. For this, hill-stream fish are known to migrate between three major habitats: A wintering habitat, a feeding habitat and their spawning habitat.

Dams and other diversions for river regulation are seen to impact fish in five major ways:

  • Obstruction in the ascent of fish in their migration for spawning.
  • Reservoirs can inundate spawning habitat, silting up gravels,
  • Changes in river water quality due to inter-basin transfers and stratification of water.
  • Natural flows downstream are radically altered. This includes abruptness of changes in flow, in volume, velocity and seasonality.
  • Prevention of young migratory fish and refuge migrants from descending to lower reaches.

In addition, adverse repercussions result from indirect effects such as the disruption of the food-webs downstream, stranding of fish during rapid flow fluctuations, and siltation in the reservoir above the dam. The chemical, trophic and thermal properties of a river are greatly  altered. Additionally, changes in slope, riverbed profile, structure of the bottom surface, submergence of gravel zones, and changes in the thermal and trophic regimes, affect the habitability of certain stretches of the river.

Designs of fish passages are many, and can be broadly categorized as follows:

  • Fish ladders. Pool and weir, baffle fishways, rock-ramp fishways, vertical slot.
  • Fish lift locks
  • Fish elevators
  • Fish trapping and hauling.
Pool and Weir Type Fish Ladder, Bonneville Dam, United States Photo: Wikipedia
Special Fish Ladder for Salmon in Sweden. Photo: Wikipedia
Special Fish Ladder for Salmon in Sweden. Photo: Wikipedia

The basic information you need for designing a fish pass, is details about the species particularities such as normal cruising speed and burst speed of target species. Some important criteria are:

  • Provision of comfortable passage for all migratory species, including the poorer swimmers, over the entire length of the fish pass. To achieve this, provision for refuge against fast currents at regular intervals should be made.
  • Year-round functionality, under different flow regimes, temperatures and oxygen levels, notably to enable fish displaced by floods to return to their initial habitat.
  • Sufficient space or carrying capacity allowing massive upstream ascents during reproductive or trophic migration.
  • Positioning the entry of the fish pass so that it is readily identifiable and accessible to the migrants.
  • Attraction of fish to the fish pass entrance in the downstream (water exit) in case of upstream migration and deterring them from dead-ends and dangerous places.
  • Positioning of upstream outlet (fish exit) of fish passes far enough from spillways and turbines to minimize the risk of being swept downstream or being damaged.

Clearly, creating an artificial fish passage is complex and would not work if the multiple aspects are not considered and provided for. Ease of physical passage is just one important aspect. Migration is specifically timed to match various conditions, and even a delay in migration can nullify the purpose. For example, upwelling and excessive turbulence in the areas near the fish entrance are undesirable, as they can confuse migrating fish from finding the entrance. For this, the gates of the dam are required to be manipulated so that the heaviest spill is at the bank opposite the fish-way, with the result that the velocity barrier forms a diagonal lead, a traffic signal of sorts, across the river to the fish entrance. Apart from a sufficient ‘attraction flow’ at the entrance of a fish pass, projects elsewhere have experimented with directing fish traffic with the help of guiding screens, and the use of overblown ‘traffic signals’ such as acoustic arrays, strobe and mercury lights, and even electric fields.

At a fish passage such as the array at Kurichhu, it is critical that at the entrance of the fish-way, the gate is to be manipulated to ensure possible passage of fish. Depth and velocity to suit particular species need to be maintained. CIFRI recommended a ‘compromised’ depth of 25 cm to be sufficient to allow fish passage. In addition the gates should be regulated to ensure that all the baffles are submerged, allowing the fish to swim over them upstream comfortably. This was not the case, when we visited, the flow level did not allow for the baffles to be submerged, as visible in the photograph as well.

Even with a depth of 25 cm in the fish exit, the variable head-height as per the draw-down of the reservoir can create a higher velocity than desired. While CIFRI warns that this poses apprehensions regarding hindrance to fish migration, they dismiss these apprehensions summarily thereafter, stating that this high velocity is observed only for a short distance, which fish would be able to negotiate using burst speed (high speed, short duration). CIFRI mentions that it is only when the speed at the water entrance or any other point exceeds burst speed, (5-6 m per second) that fish would be unable to cross this speed barrier.

While variables such as water temperature and fish length are determinants of swimming speed of fish, CIFRI has assumed that Schizothorax  and Barbodes can swim at 3-5 and 2-4 m per second respectively. They have taken the flow speed of water with head height, and fitted it to the equation for determining the velocity through the orifices in or over the baffles, and they are estimated to be ranging from 2.69 to 2.80 m per second, which they say, ‘permits the fish to cruise through the fish-way comfortably.’

There are some doubts here. Even a short distance of one baffle, or at just the entrance is critical, because if that is unpassable, the entire fish-way is unsuccessful. Further, CIFRI has arrived at burst-speed of fish for this river not by actual studies on specific species, but by inference from studies on fish in other countries. What strikes as doubtful about this basis, is their assumption that all other things being equal, a fish of any species is capable of equal burst speed, provided it is of the same length. This does not match anything one sees as evidence in the occupation of different fish species in different river stretches, nor in their striking speed while feeding competitively.

In order to test whether the fish ladder was ‘working’, CIFRI officials operated the fish pass in March (the beginning of the migration season) for 3 days and then closed the sluice gates to check. They found Schizothorax richardsonii, Garra gotyla and G. lissorhinchus in the top-most pool. They did it again in June and found 8 species in the uppermost pool. While it is clear from this that some fish are making it up the channel right upto the top pool, they have no way of knowing for sure whether they were getting through the 25 cm gap at different draw-down levels.

The critical question here is not just whether some fish are making it up the channel, but which species, how many, and are breeding populations making it up on time? A relevant study cited on the April 2013 issue of the Yale Environment 360, titled ‘Fish and hydropower on the U.S. Atlantic coast: failed fisheries policies from half-way technologies’ by J.Jed Brown and 6 other co-authors (Conservation Letters, Vol 6. Issue 4, p 280-286, July/Aug 2013) is instructive. The discussion by co-author John Waldman is titled ‘Blocked Migration: Fish Ladders on US dams are not effective’, citing this study goes on to say that fishways on rivers in the U.S. Northeast are failing, with less than 3 percent of one key species making it upriver to their spawning grounds.

 Waldman says that “in most major rivers in the U.S., maintaining some semblance of the integrity of migratory fish runs past hydropower dams is dependent upon the fish using ladders and elevators”. They undertook a study of the success – or, rather, failure – of Atlantic salmon, American shad, river herring, and other species in migrating from the sea to their spawning grounds past a gauntlet of dams on three rivers in the northeastern U.S. – the Susquehanna, Connecticut, and Merrimack. Waldman says “what we found was grimmer than we expected. For one species, American shad, less than 3 percent of the fish made it past all the dams in these rivers to their historical spawning reaches.  The sobering aspect of these contemporary studies is that they are based on the insubstantial number of fish today as compared to earlier massive migrations of these species, which numbered in the many millions. For the international community, the record of fish passage on rivers in the northeastern U.S. is a cautionary tale”.

He goes on to say that “hydropower has often been billed as a clean source of renewable energy, and generating electricity without polluting the air or producing greenhouse gases is commendable. But ‘clean’ is in the eye of the beholder, and any claims to being sustainable ignore its multifarious aquatic effects, including blocking fish passage, fragmenting habitat, and undermining a river’s fundamental ecological services.”

What Brown and co-authors found was bleak. One metric used was the percentage of fish passing the first dam that also passed just the second dam. For shad, the numbers were 16 percent on the Merrimack, 4 percent on the Connecticut, and 32 percent on the Susquehanna. But on these rivers, Waldman says, the second dam is only the beginning of the journey, and these rivers have multiple dams blocking access to historical spawning reaches. It’s important to put these results in perspective because they are merely relative to the present paltry numbers of fish that even attempt to migrate up these rivers.

The study says that there are three absolute numbers that matter. One is how many ran annually before the dam was created, the second is the numbers targeted for restoration in fish passage programs, and the third are the numbers that actually show up each year. On all the rivers examined by the study, restoration goals were in the hundreds of thousands of fish – at least one, if not two, orders of magnitude less than historic, pristine runs. Yet run sizes obtained across three decades ranged annually from a high of about 10 percent to, more commonly, 2 percent or less of the stated goals.

There are two significant aspects worth taking note of here. First, the three absolute numbers that matter, as mentioned in the paragraph above. The construction of a fish ladder must come with quantified stated goals, in terms of the number of fish that are required to pass as minimum, to achieve the desired stability of fish populations. This requires an estimate of populations prior to building the dam, and an estimate of the number that migrate unimpeded, as well as specific population dynamics. Fish migrations in large rivers can be in the millions, as already cited here from Brown and Waldman’s study. Here at the Kurichhu, or any other fish-pass in India, population and migration estimates, let alone quantified goals are a far cry.

Secondly, the study clearly illustrates that every subsequent dam upstream has a cumulative  impact on the numbers of fish succeeding upstream, diminishing in orders of magnitude. This brings to the fore the critical importance of considering cumulative impact of multiple projects, despite ‘mitigation measures’, along an entire stream-length, before any clearance is given piece-meal.

While on the design for fish-passes on specific hydro-projects, there are many aspects other than physical passability provided by a fish-pass, that determine its success or failure. Changed flow, turbulence, and volumes can be disorienting for fish leading to serial delays, making it unlikely that the many fish make it to the spawning reaches at the optimal time in the river’s seasonal ecological cycle. The numbers of adults successfully returning downstream past the dams also sacrifice their future spawning potential. The flow out of an operating fish-ladder is often very small compared to the water going into the intake to the turbines, and fish will often choose the larger flow during descent, to their peril. At Kurichhu for example, the flow down the fish ladder is just 0.80 m³ a second, which is a fraction of the flows for the 4.75 m diameter intake of any one of the four 15 MW turbines.

There is also the larger question of flows in a river being regulated by series of dams, and sometimes being too low to provide the necessary cues for hormonal change and migration, puts paid to fish even reaching fish-ladders in the first place.

The study by Brown and colleagues in the US says that despite vast spending on modern technologies, contemporary shad migrations on these rivers are at least three to four orders of magnitude below the original unfettered run sizes, with similar results for salmon and river herring. While dams alone don’t explain these results; overfishing, habitat destruction, and alien species contribute – but there is widespread consensus among fish biologists that dams (such fish-passes notwithstanding) are a primary cause. Surely, a cautionary tale for India.

And here is another cautionary tale for India, where unlike Bhutan, fish are eaten, readily. Thirty-three years ago, standing on the Sutlej Barrage at Ropar in Punjab, I witnessed a strange sight. At the base of the barrage, there was some urgent movement in the cold blue waters of the Sutlej in early spring. Mahseer fish were attempting to migrate up and beyond the 10 meter high barrage. There, right along the buttress of the sloping spillway, one could see a living pyramid of thousands of fish upon fish, slithering up the side of the uni-dimensional triangle against the spillway, barely submerged in the leaking flow from one of the gates, and wriggling on top of and past each other, in a futile effort to make it over the barrage. While this may just have been a collective shoal strategy to get past smaller rapids, it was a death-trap for fish there, against a steep and high barrage. Some other men had already seen this, and I could see them wade up to the desperate and tenuous pyramid in knee deep water below the barrage, and carrying away fish in sack-loads.

Hydro-power projects in India may undertake to construct fish-ladders projected as mitigations measures to obtain environmental clearance, but that does not prevent the staff and others from making the best of the concentration of fish at the base of the fish-ladders and even at un-passable barrages and predating on them. The CIFRI study for the Kurichhu mentions that Indian workers hired by NHPC regularly fished at points of concentration during migration season, nullifying the purpose of the fish-pass. Clearly, the dam authorities will also need to be charged with the responsibility for protection of fish-passes, and other points of concentration even on dams without fish passes.

These are some of the aspects that require to be further investigated about fish-passes in our Indian context, and to be put on the table for discussion and closer scrutiny when mitigation measures are proposed by hydro-power projects.

Editor’s Note from SANDRP:

When the rivers in Himalayas are facing huge impacts of cascade hydropower projects, it is important to look at the role played by organisations like CIFRI ( Central Inland Fisheries Research Institute) which is supposed to be Asia’s “premier facility in the feild of inland fisheries research” CIFRI was hired as a consultant for recommending eflows for Teesta IV HEP in Sikkim and 780 MW Nyamjangchu HEP in Tawang, Arunachal Pradesh. In the case of Nyamjangchu, CIFRI recommended a flow of 3.5 cumces from the proposed barrage point, which is 14% lower than the lowest flows recorded (extrapolated) for that site. It is highly improbable that even CIFRI’s target species of snow trout will be able to sustain these drastic flow reductions. CIFRI has not raised a voice when multiple dams are being planned without fish ladders or realistic mitigation measures across the country when protecting riverine fish and fisheries is a part of its mandate.

In a strange contradiction, although India’s NHPC has built Kurichhu HEP and CIFRI has designed the fish ladder for a dam that is 55 mts high, the EAC of the MoEF in India unilaterally thinks that fish ladders do not work for dams, even as high as 42 meters, This EAC also includes representative from CIFRI.

Before concluding that fish ladders will or will not work in India, we need extensive studies on this subject for different rivers and projects. Unfortunately, none are being undertaken, in line with our overall apathy towards riverine fish diversity and fisheries. Good, scientific  studies will help in designing ladders which can be useful for species specifically found in Indian rivers, or will conclude that ladders will not work in specific cases, in which case, the irreversible impact of the project will have to be looked at in a perspective beyond ‘mitigation measures’.