Pauk, Heo, Tato-I Hydropower projects: CISMHE’s shoddy EIAs Seven Big hydro on third order tributary of Brahmaputra!

India is well aware of fury of ‘Mighty Brahmaputra’[i]! The 2900 KM long river is prone to catastrophic flooding in monsoon when the Himalayan snows also melt. It is a classic example of a braided river and is highly susceptible to channel migration and avulsion[ii]. What we seem not to be aware of is the consequences of damming every single tributary at multiple sites in the name of hydro power projects.

Hydro Power projects proposed on Yarjep River
Sr. No. Name of the Project Installed Capacity
1 Pauk HE Project 145 MW
2 Heo HE Project 240 MW
3 Tato-I HE Project 186 MW
4 Rapum HE Project 66 MW
5 Rego HE Project 80 MW
6 Kangtangshiri HE Project 80 MW
7 Pemashelpu HE Project 91 MW
Source: EIA Reports of Pauk, Heo and Tat-I HEP

Consider this: Might Brahmaputra has large number of tributaries, one of them, albeit the main one is Siang river, constituting just 2% of the Brahmaputra basin. Siang has many tributaries, one of them is Siyom River. Siyom has many tributaries, one of them is Yarjep. & now this Yarjep river, third order tributary (when enumeration is done in tree format, starting from main river) of Brahmaputra, is to have seven large hydropower projects with total installed capacity of 888 MW. Three of the largest among these projects together came before the Expert Appraisal Committee of Union Ministry of Environment and Forests for River Valley Projects during their meeting on July 3-4, 2014. All three projects have common developer, namely Velcan Energy[iii] & common EIA (Environment Impact Assessment) consultant, namely Centre for Interdisciplinary Studies of Mountain & Hill Environment  (CISMHE)[iv]. Having been established as a R&D centre by the Power Ministry, there is an issue of conflict of interest since Power Ministry agenda is to push all hydropower projects, but an EIA consultant is supposed to be an independent entity.

L section

The story of river Yarjep in the State of Arunachal Pradesh which is a small part of Brahmaputra River System can help us understand the larger canvas of much ambitions hydro power spree the state is on.

Siang basin Yargyap Basin

Arunachal Pradesh government and the central government plan to make Arunachal Pradesh the ‘future powerhouse’ of the country. Siang basin is considered the largest basin in terms of hydropower potential in Arunachal Pradesh, the present estimated potential is 18293 MW it has over 18000 MW of power potential, which is planned to be harnessed by setting up about 44 hydropower projects spread throughout the basin. Department of Hydro Power Development, Government of Arunachal Pradesh has allotted 39 projects, which are at various stages of survey and investigation. Five projects are yet to be allotted which includes two major projects viz. Siang Upper Stage I (6000 MW) and Siang Upper Stage II (3750 MW), which are in investigation stage.

Such a large-scale development which is expected to take place over a period of next 10-15 years will cause huge environmental impacts and exert tremendous pressure on carrying capacity of Siang basin. Cumulative Impact Assessment and Carrying Capacity Assessment of Siang basin which was conducted by CWC as directed by Inter-Ministerial Group (IMG) in Feb., 2010 on the directions of Prime Minister’s Office (PMO). The study is yet to be approved through a credible participatory process. The study itself has very serious shortcomings[i].

There is an attempt to delink the sanctioning of the individual projects from the CIA & CCA study of the Siang Basin. Even before the report is accepted by MoEF, the ministry is considering three projects proposed in a cascade on Yarjep River of the Siang Basin. Pauk HEP (145 MW), Heo HEP (240 MW) and Tato-I HEP (186 MW), have been proposed as a cascade and were considered for EAC in its 75th meeting held on 3-4th July 2014 for grant of EC (Environment Clearance). EIA studies conducted by Centre for Inter-Disciplinary Studies of Mountain & Hill Environment University of Delhi, Delhi (CISMHE) for all the three projects were submitted to the EAC. Considering these projects is also in clear violation of the MEF order of May 28, 2013 which required that no project beyond the first project be considered in any basin without a cumulative impact study. Siang basin supports spectacular biodiversity as well as anthropological richness in India. Any decision in this basin needs to be taken carefully. Siang CIA CCS Study is a step in that direction which can guide EAC’s decision making regarding Siang Basin projects only after it is completed through a credible process.

All the three EIA reports have serious inadequacies. The EIAs have been conducted in a very project specific manner and do not reflect the cumulative nature of impacts. The EIA reports for the schemes present the respective schemes as Run of the River Schemes (ROR) even when the projects talk of peaking generation and also have large storage of water proposed. The report at several places reflects pro hydro bias. Impact prediction and assessment is highly inadequate and completely bypass the cumulative impacts. The report also shows casual approach towards prediction and mitigation of impacts. SANDRP recently made detailed submissions to EAC after reviewing the EIA reports, EMPs (Environment Management Plan) and Public Hearing reports of the three projects. Highlights of the submissions are given below.

Pro hydro bias Opening chapters of the EIA reports (Apart from Developer’s Foreword, which is inappropriate in an EIA Study) of the EIA begins with ‘Need of hydropower’ and ‘Power potential of Arunachal Pradesh’. This is not expected from an EIA. This does not lay grounds for unbiased impact assessment and supports the project implicitly from word go.

Consultants not aware of policies and Acts Para 1.5.1 the EIA says: “In the course of its development, the Tato-I HEP needs to adhere to all relevant policies and guidelines in general and the following, in particular:

i.) National Forest Policy (NFP), 1988

ii.) National Water Policy (NWP), 2002

iii.) National Rehabilitation and Resettlement Policy (NRRP), 2007

iv.) Rehabilitation and Resettlement Policy (RRP), 2008 of GoAP”.

This shows that the EIA consultants are not even aware of latest policies and Acts. For example, the latest Water Policy is National Water Policy of 2012 and latest R&R Act is that of 2013.

Misleading claim: These are NOT ROR schemes All the three EIA reports keep referring to the projects as ROR schemes. The Executive summary of all the EIA reports starts with a strange statement, “Such (“midsized ROR”) kind of projects is highly environment friendly”, which is clearly wrong and has no place in an EIA. This is not an ROR project, since it also hopes to do peaking power generation. EIA report of Pauk HEP states “2.4.1 One storage capacity in the most upstream project, Pauk, is sufficient to regulate the natural flow during the lean season, and to ensure the diurnal peaking hours of the entire cascade.” While EIA report of Tato-I states that master and slave relationship has been attributed to Heo HEP (master) and Tato-I HEP (slave) due to 94% to 98% direct dependency of Tato-I flows for power generation. The report also states that during peaking power generation for about 3 hours in lean season, ungated trench weir can supplement flows. Pauk HEP has dam with live storage of 1.67 million m3 and Heo HEP has dam with live storage of 0.15 million m3. Dam storage and peaking generation in these cascade projects disqualify them as RoR projects since the projects will be changing the downstream hydrograph, which ROR projects cannot do. The proponent and the EIA consultant are misleading the MoEF as well as investors, statutory bodies and general concerned public that this is an RoR project, thus painting a falsely benign picture of the project.

Hanging bridge

Missing aspects of impact assessment Many of crucial aspect of impact assessment are completely missing.

  • Word ‘Climate Change’ does not feature in EIA report or in the EMP. No assessment of the possible impact of climate change on the project and impact of the project on the local climate as well as increase in green house gas emissions from the reservoir and construction of the project has been done.
  • Similarly impact of the project on adaptation capacity of the local communities in changing climate has not been assessed.
  • Impacts of the dam on the flood character of the river, what will be the changes and how these will impact downstream areas are not assessed.
  • Impacts of changing silt flows downstream from desilting chamber and from silt flushing in monsoon on the downstream areas are not analyzed.
  • Impact on the disaster potential in the project area as well in the downstream due to construction and also operation at various stages, say on landslides, flash floods, etc. is not assessed.
  • Impacts of peaking generation have not been assessed. When a project operates as peaking station, there are severe impacts in the downstream and also upstream (rim stability). These impacts have not been assessed, nor is it assessed how the project will perform in the cascade development it is in.
  • EIA reports of the Heo and Tato-I projects conveniently adopt the site specific seismic study carried out for Pauk HEP by IIT Roorkie stating that “In view of proximity, size of the structure, similarity of lithological/ tectonic features, location in the same geotectonic block, and absence of any major additional tectonic features, it is considered appropriate”.


Impacts on Fishes: The report shows quite a disregard for these migrating species. No mitigation measures for the habitat fragmentation of these species are considered. Schizothorax richardsonaii, Schizothoraicthys prograstus are the two migrating species among the eight species found in the Yarjep river. EMPs for all the projects make no provision for fish ladder or pass stating that the two species can survive in lentic as well lotic waters. The consultant has used only the schizothorax species as an indicator for assessing impact of changes in discharge, depth and velocity. Such assessment based on single species downplays the impact on other species like smaller fish, benthic macro and micro invertebrates which form an important part of the food chain which also supports the target specie. This is also in violation of original TORs.

Playing down fisheries diversity: The chapter on Fisheries compares fisheries in Yargyap, which is Siyom’s tributary with Siyom and concludes that the icthyological fauna is lesser than Siyom. That is a flawed comparison as Siyom has a bigger drainage area and is a bigger river. Siang CIA CCS Study indicates presence of additional RET fish species than EIA Report.

Non fulfillment of TOR: According to the original TORs dated 09/2008: The assessment of eflows stated: “Estimation of environmental flow for the aquatic species and river morphology”. However, the study forgets this TOR and focusses only on Schizothorax species and does not comply with the ToRs. There are issues of merit and significant impact here and the eflows assessment part of the EIA study needs to be redone.

Turbine designs also need to be changed to protect downstream migrating fish from being mortally injured by the turbine blades. Precautionary measures like bubble walls, acoustic barriers, racks etc., have to be adopted to avoid fish mortality in the turbines for downstream migration. None of these measures are even explored, although the TORs asked for measures to aid fish migration. This is not confirming to the TORs and hence this part of the study needs to be done again.

Non fulfillment of TORs:

  • Eflows discharge designs: The TORs state that the EIA should contain : “The design details for ensuring minimum environmental flows should be provided in the EIA/EMP report.”
  • Aiding fish migration: The TORs had also asked the proponent to explore ways to aid fish migration and ladders. The proponent’s response does not deal with this. In fact the proponent states: “The height of dam of Pauk H.E. project is more than 100 m so that fish ladders are not proposed for Pauk considering its feasibility.”
  • Although ladders may not be feasible for Pauk HEP there are a number of other ways like passes, fish lifts and a combination of ladder and lifts that can be explored to aid fish migration, as is being done the world over. Fish ladder in any case should have been considered for Heo and Tato I trench weir.

Dangerous Mitigation measures suggested Mitigation measures suggested in the EMP like River channelization are downright dangerous, indicating the flawed impact assessment by the consultant. Reinstating Habitat complexity downstream of dam stretches is one of the mitigation measures for fish conservation. Many countries are working towards reinstating this habitat complexity by introducing boulders, creating riffles, etc, while the Pauk EMP actually suggest removing boulders and channelization of river between dam and powerhouse, which will increase the impacts downstream!

Impacts of tunneling and blasting on geophysical aspects of the region: All the three EIA reports summarize the impacts on landslides in single sentence: “The HRT might disturb the water tables. In addition, blasting, quarrying and road construction activities may give rise to landslides and slips in the area.” In the EMP no specific measures have been suggested for landslides.

All the projects require about 2.7-3 ha of land for underground works such as Head Race Tunnel (HRT), adits and related works. This will involve tunneling and blasting works. No detailed assessment of impacts of tunneling and blasting works involved in this construction in terms of spatial assessment of areas to be blasted and their overlap with ecologically sensitive and geologically fragile areas has been done. Impacts of blasting on local water resources such as springs, impact on the houses, impact on wildlife has not been detailed. No preventive measures have been suggested in the management plan. This again shows non serious attitude of the EIA agency.

Free flowing river stretch: There is no mention of what is the flowing river stretch downstream & upstream of the projects. This point was raised in 34th EAC Meeting held on 19-20.01.2010 and it was observed that as there is no free stretching of river between the three contiguous projects (Pauk, Heo and Tato-I) the river will be a pull of water for a stretch of about 14 kilometers. However, the report does not talk about free flowing river stretch at all.

New Picture


Unless this length is assessed and is found to be adequate for river to regain its vitality, the project should not be considered and it should be asked to change the parameters as per the need for flowing stretch between projects. In any case this stretch should not be less than 1 km between any two projects, which is the current EAC norm.

Environmental flows: Section on Environmental Flows discusses all three projects together. These three projects will change the character of at least 14 kilometers of the river and also beyond. The Environment flow should be assessed through a Building Block method which has not been done, one of the key requirements for building block method is participation of all stake holders.

It has to be noted that the Powerhouse discharges from Heo do not enter the river at all, but are intercepted by the water conductor system of Tato I which also diverts additional water through ungated trench weir. So the section of the river which carries only environmental flows is significant, highlighting the importance of holistic e-flows recommendations and not one focused on single species.

As stated in the Pauk and Heo reports, large no of data is from years 2009-10, more than three years old now and in any case before the TOR approval given in 2011. This is clearly in violation of the MEF norms.

No details of how the e-flows will be released and monitored have been given in the EIA. This is a serious lacuna as we have seen that e-flows recommendations remain on paper in the absence of clearly defined discharge mechanism and robust monitoring.

Impacts on the wildlife:Impact of clearing forests which would result in land cover change has been stated in the reports as “small in magnitude.” The EIA report categorise the impacts on wildlife as “temporary” stating that they would last up to the end of construction period only. This is clearly wrong considering that the change in downstream river flows in operation phase will have impact on aquatic and terrestrial wildlife.

The most affected animal species in the surroundings are Common leopard, Leopard, cat, Jungle cat, Barking deer, Wild boar, etc. However no detailed assessment of their habitats and corridors has been carried out. The Heo EIA report surprisingly states that “Contrarily, the diversion of water in the downstream part of the river may open new corridors for the movement of animals. It is considered as positive impact.” (p. 301 Volume-I EIA Report) Which new corridors the report is talking about when there is ZERO distance of free flowing river between the projects? There are clearly contradictions and that shows how non serious the EIA agency is.

The report also clearly does not recognize the hazard of animals getting washed away with sudden release of discharge.

No assessment of Cumulative Impacts The project lists seven projects on rive Yarjep. The report claims (clearly an unsubstantiable claim) that the cumulative impact assessment study has been conducted only for the three projects in the cascade development. The model for computing environmental-flows is site specific and focused on the Yarjep river part related to the Pauk, Heo and Tato-I HEPs only. (p. 277 Volume-II EIA Report) While report makes a brief mention of cumulative impacts on different environmental components, there is no detailed assessment of any of the cumulative impacts. This is clearly unjustified looking at the large number of hydro power projects on Yarjep River. The report has completely failed in having serious attitude towards the cumulative impacts assessment.

EIA report completely misses out on the detailed analysis of cumulative impacts in terms of

  • Impacts on flora, fauna, carrying capacity, livelihoods
  • Impact of reduction in adaptive capacity of the people and area to disasters in normal circumstance AND with climate change
  • Impacts on springs and drainage pattern
  • Disaster potential of the area
  • Tunneling and blasting
  • Muck disposal
  • Changed silt flow pattern in different phases
  • Cumulative downstream impact
  • Cumulative impact of hydro peaking
  • Implementation of measures for safe operation (e.g. as recommended by SANDRP[ii])
  • Mining of materials for the project
  • Cumulative disaster management
  • Geological disturbance caused
  • Seismic impacts
  • Impact of construction and operation of coffer dams and diversion tunnel

Siang Basin cumulative impact study is still to be approved through a credible participatory process. The study itself has very serious shortcomings, see: https://sandrp.wordpress.com/2014/02/18/cumulative-impact-assessment-study-of-siang-basin-in-arunachal-needs-urgent-improvement/. The study also needs to be discussed by EAC and no projects in the basin should be considered till all this process is over. Considering such projects will also be in violation of the MEF order of May 28, 2013.

Issues with Rehabilitation & Resettlement Plan Rehabilitation and Resettlement plan of the project refers to National Policy on Rehabilitation and Resettlement (2007) and Resettlement & Rehabilitation Policy of Arunachal Pradesh Government (2008). (p. 120 Volume-II EIA Report) This is clearly wrong; the new R&R Act of 2013 has to be made applicable. The PP should be asked to redo the R&R Plan in consultation with the affected people, EMP and cost estimates and come back. The R&R Plan should also include compensatory measures for all social impacts in the upstream and downstream, not only for those who lose land or houses.

Public Hearing minutes not included: The EIA is supposed to include the full minutes of the Public hearing, which has not been included in this report, violating the legal norm. Instead, the EIA indulges in biased unwarranted statements of “Everyone Clearly supporting Pauk HEP”. The public hearing report for the Heo HEP has several shocking statements from the DC, which seems to raise the suspicion that the public hearing has not been conducted in free and fair manner and should be asked to be conducted again, this time by an independent panel.

Conclusion Looking at the fact that the Siang Basin study is yet under consideration and the EIA reports of Pauk, Heo and Tato-I projects fail to assess the project specific & cumulative impacts we sincerely hope that the EAC will not accord environmental clearance to these projects & will also call for fresh public hearings after EIAs have been redone.

We also see it alarming that all the three EIAs by CISMHE are so fundamentally flawed. If this is the way we are going to conduct EIAs, we are not even in a position to make informed decisions about such massive interventions in such fragile, vulnerable areas. Should CISMHE, having been set up by the Power Ministry itself, be doing an EIA is another question that needs answer.

Amruta Pradhan <amrutapradhan@gmail.com>


Sources for Photographs

Bridge on River Yargyap (Yarjep): https://www.flickr.com/photos/siddiqui/4366973498/

Menchuka Plains: http://ajaishukla.blogspot.in/2012/03/menchuka-visit-to-shangri-la.html

Quite flows of Yarjgyap (Yarjep) River: http://article.wn.com/view/2014/03/08/Arunachal_govt_to_plead_Centre_for_road_via_Bhutan/


[i] See: https://sandrp.wordpress.com/2014/02/18/cumulative-impact-assessment-study-of-siang-basin-in-arunachal-needs-urgent-improvement/

[ii] See recommendations section in: https://sandrp.wordpress.com/2014/06/12/nadiya-bairi-bhayi/

[i] https://sandrp.wordpress.com/2013/07/17/brahmaputra-the-beautiful-river-or-the-battleground/

[ii] Catling, David (1992). Rice in deep water. International Rice Research Institute. p. 177. ISBN 978-971-22-0005-2. Retrieved 23 April 2011.

[iii] http://www.velcanenergy.com/

[iv] Centre for Interdisciplinary Studies of Mountain & Hill Environment, a Delhi University centre, established by Union Power Ministry: http://www.cismhe.org/

8 thoughts on “Pauk, Heo, Tato-I Hydropower projects: CISMHE’s shoddy EIAs Seven Big hydro on third order tributary of Brahmaputra!

    1. Yes, but EAC neither got any satisfactory replies to issues we raised, nor did the EAC apply its mind to the questions and responses. The decision remains legally challenge-able.


  1. I live in France and I am a shareholder of Velcan. I am concerned with environmental issues hence my interest in your blog.


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