Arunachal Pradesh · Expert Appraisal Committee

Hydromania in Arunachal Pradesh: Massive 1850 MW Dam Planned Without Any Basic Data, Not even Water Flow Data…

‘MoU Virus’ was the term used by former environment minister Jairam Ramesh in May 2008 to describe the speed at which the Memorandum of Understanding or MoUs for hydropower projects were signed by Arunachal Pradesh government. Five years after that virus attack, the ill-effects are clearly visible. The construction of Lower Subansiri hydropower project has been stopped for 26 months now. Environment and Forest clearances are yet to be accorded to 3000 MW Dibang Multipurpose dam, even though the foundation stone for this dam was laid by none other than the Prime Minister Dr. Manmohan Singh on 31st January 2008. Lower Siang hydropower project public hearing was vehemently opposed by people. But learning no lesson from these, the government of Arunachal Pradesh and the center is going ahead with its gigantic plan to make Arunachal Pradesh the ‘future powerhouse’ of the country. In doing so scientific studies and ground realities have been blatantly neglected.

Oju hydropower project in the Subansiri river basin with a proposed installed capacity of 1850 MW is the latest example of the hydromania, which has gripped the government of Arunachal Pradesh and the center. Oju HEP is the upper most project proposed on the Subansiri river in the Upper Subansiri district with a catchment area of 9827 sq. km. up to the dam site. The project was considered for Terms of Reference (TOR) or first stage of environmental clearance by the Expert Appraisal Committee on River Valley and Hydroelectric projects (EAC) in its 72nd meeting held on 20th and 21st February this year. But there is little information available about the actual situation of the project area.  Before going any further, consider the following situations –

Any scientific study is yet to be done at the dam site. Water flow data which is a prerequisite for construction of a hydropower dam is not available for the proposed dam site. No gauge and discharge measurement site at the project site or anywhere in the catchment of the dam.

The project area is totally under forest cover. It holds rich biodiversity which is yet to be explored.

* There is no road to reach the project area. The distance between the dam site of Oju hydropower project and Limeking town, the last point of motarable road is 60 km. From Daporijo, the headquarters of Upper Subansiri district, the dam site is 210 km away. 

Tentative Road Network to Project Site Source: Oju PFR
Tentative Road Network to Project Site
Source: Oju PFR

A small hydropower project is proposed to be constructed in a nearby stream in order to fulfill the electricity requirement during the construction of the project.  

SNC-Lavalin, the consultants hired for preparation of detailed project report, is known to be one of most corrupt engineering firms in the world.

All the situations mentioned above are drawn from the project documents submitted to MoEF. It was shocking to find that without any environmental baseline assessment, the Pre Feasibility Report and Form I made all kinds of sweeping assertions. This hydromania is leading to nothing but ignorant, unscientific and corrupt decision making. 

SANDRP after reviewing the project documents, made a detailed submission to EAC on February 13th pointing out the critical issues related with Oju HEP. We asked the EAC not to consider the project for TOR clearance. We also demanded that the project proponent should  be  asked  to  get  at  least  five  years’  daily  water  flow, gauge, rainfall and sediment data at the project site before applying for TOR clearance. The critical issues mentioned in SANDRP’s submission on Oju HEP to EAC are listed below.

Critical Issues of Oju HEP

No More Projects Should be Cleared in Subansiri basin before Completion of Basin Study From 20007 to 2013, four projects in Subansiri basin has been considered by EAC along with one sub-basin study. All the four projects have been given TOR clearance. Subansiri Upper HEP has been given TOR extension on 6th June 2013. The total installed capacity of these projects are 4960 MW. It is also important to note that 2000 MW Lower Subansiri project is in under construction phase. This implies that nearly 6960 MW of capacity has already been given clearance by EAC without any cumulative impacts assessment study of Subansiri basin being completed through a participatory process. This capacity is in addition to the small hydropower projects in the basin.

The Subansiri sub-basin study was discussed for the first time in 68th EAC meeting in 2013. In that meeting the EAC had stated that “optimal number and locations of HEPs and similar projects to be planned in the basin conforming strictly to ecological and environmental sustainability is to be clearly delineated.” This can only be known once the basin study is completed.

In this situation, no more projects in Subansiri basin should be given any clearance till the cumulative study is being completed. Besides, the EAC must take into account the fact that cumulative impact assessment study of the basin is major demand of the organizations whose agitation has stopped the construction work of Lower Subansiri with the support of the people of Assam. Therefore it is very essential that a through and detailed cumulative impact assessment study is done for Subansiri in participation with all the people of the basin. Without this, clearances given to projects would face the same fate as the Lower Subansiri project is now facing: Work stopped for 26 months till now.

A list of projects cleared by EAC in Subansiri basin is given below.

Sl. No Project State Sub-Basin Ins Cap Status Meeting date Total Area Req. ha Forest Land, ha
1. Subansiri Lower AP Subansiri 2000 Under construction EC on 16-07-03 4111 4039.9
2. Subansiri Middle AP Kamla 1600 TOR Approved 25-09-10 3180 1333
3. Nalo HEP AP Subansiri 360 TOR Approved 11-12-11 662.94
4. Naba AP Subansiri 1000 TOR Approved 03-05-13 658
5. Subansiri Upper AP Subansiri 2000 TOR Ext Granted 06-06-13 3155 2170

Premature application Reading the PFR and Form I on the EAC website shows that project has come rather prematurely for TOR clearance. There is no gauge and discharge measurement site at the project site or anywhere in the catchment, the nearest site is at Upper Subansiri dam site with catchment area about 50% higher than that of Oju HEP. Even for this site, the flow measurement observations are available only for 6 years. How can optimum parameters of a massive project with 1850 MW capacity be formulated without any flow measurements, which is the most important parameter for hydropower project. Even now the flow measurements do not seem to have begun. There are no roads to the project area. It should be remembered that this is a virgin site, and there have been no environmental baseline assessments and yet the PFR and Form I are making all kind of sweeping assertions. The PP should be asked to get back with such an application only after they have at least five years of observation data of water flow and other parameters. That the application is premature is also apparent from the drastic changes the project capacity has gone through so far, as described in PFR. 

Oju HEP's nearest gauge is located in Menga, also the site for Subansiri Upper HEP. But there are four hydropower projects planned between Oju and Subansiri Upper.  Source: Form I of Oju HEP
Oju HEP’s nearest gauge station is located at Menga which the site for Subansiri Upper HEP. But there are four hydropower projects planned between Oju and Subansiri Upper. Source: Form I of Oju HEP

This premature-ness of the proposal is further confirmed when we see contradictory figures in the submitted documents about basic project parameters. For example dam height is given as 110 m (sec 8) at one place and 115 m at another place. Live Storage capacity is given as 2.065 MCM at some place, 3.3 MCM elsewhere (e.g. sec 4.4 of PFR). Power intake design discharge is given as 327.4 cumecs at some places and 333.39 cumecs elsewhere (e.g. sec 2.2 of Form 1).

Proposal in contradiction with Cumulative Impact Assessment This proposal before EAC for a 1850 MW Oju project is in contradiction with what is given in the Cumulative Impact Assessment (CIA) commissioned by the CWC and which was discussed in the 68th meeting of  EAC. The CIA says (see para 3 of Ex Summary) that there are two Oju projects: “Oju – I (1925 MW), Oju – II (2580 MW)”. However, the proposal now before the EAC is one project with capacity lower than any single project! However, Table on page 15 of CIA says Oju I has 700 MW and Oju II has 1000 MW capacity! The CIA says the submergence area of Oju I is 72.3 ha, though the proposal now before EAC for the same dam says the dam has submergence area of 42.3 ha! CIA says design flood is 10500 cumecs for Oju I (same dam as Oju now before EAC), but the proposal before EAC says PMF is much lower at 5983. This shocking series of numbers show that both the reports of Oju project before EAC and the CIA are misleading and do not seem to know what they are talking about. This is not an exhaustive list of contradictions, there are many more, this is only for illustration. 

Map of Subansiri RIver Basin  Source:
Map of Subansiri RIver Basin

Proposal different than allotment The PP was allotted two separate projects Oju I and II by Arunachal Pradesh government, but they have decided to club the two, but there is no agreement between Arunachal Pradesh and PP for the new parameters in the project proposed before EAC. Without such an agreement, EAC consideration of the project would be vacuous.

Huge Land Requirement The Form I of Oju project states that the area which will come under submergence due to the formation of the reservoir excluding the river bed is 34.3 ha. Including the river bed the total submergence is 43.2 ha. But the total land requirement is 760 ha implying that the required for dam, water conductor system, power house and other project appurtenances is about 727 ha. It is not clear why 760 ha of land is required for the project when reservoir submergence is 43.2 ha.

Contradictory figures about Land Requirement The Form I in the table providing basin information about the project states that “The total land to be acquired for the project is 760 ha.” But the PFR in section 12.2 in page 15 states “It is estimated that about 790 Ha of land would be required for development of the Project.” This shows that the project proponent is not clear about the land requirement for the project. 

Threat to Huge Forest area The construction of Oju HEP will be a threat to a huge forest area. Page 17 the Form I states “…760 ha of land with forest cover is to be acquired for the project. Forest cover is also observed within the project as well as area within 15 km from the project site.” But the PFR does not specify how much forest area will be actually diverted. 

River Subansiri flowing through its lush green valley
River Subansiri flowing through its lush green valley

Installed Capacity is more than 1850 MW The installed capacity of Oju project is more than 1850 MW since a dam toe power house of 28 MW is also planned. This makes the total installed capacity in 1878 MW. The documents in most of the places mentioned installed capacity of the project as 1850 MW. The EAC therefore should ask the project proponent to apply for fresh TOR clearance with renewed installed capacity.

Oju Project Proponent aims to Construct Three Projects in the Name of One: Small Hydro project to Power the Construction Work The EAC should take a note that project proponent of Oju, is aiming to construct three hydro power projects in the name of one. We have already mentioned about the first two. Now in section 10.7 of page 10-7, the PFR documents states “The power requirement for construction activities is estimated to about 25.0 MVA taking into consideration the capacity of electric driven equipments which are to work during the construction period and lighting. The possibility of constructing small hydro power plants on streams in the vicinity of the project would also be explored at DPR stage.”

The Form I also mentioned about small HEP in page 10 -“The estimated peak requirement of power is about 25MW required for construction activity of major works such as tunnels, adits, barrage area and power house complex. Construction power requirement is proposed to be met by DG Sets/Small HEP.” Full details including impact assessment of this small HEP should be included in the TOR.

Stretch of Free Flowing River between Two Projects on Subansiri It is not clear how much flowing river stretch is available between Oju and downstream Nare HEP. According to the minimalist norms followed by EAC the free flowing stretch between two projects should be minimum one kilometer. But the PFR of Oju HEP have not clearly mentioned this distance anywhere. The Cascade development figure given in the PFR says that the elevation difference between TWL of Oju (1300 m) and FRL of Nare (1280 m) is just 20 m. If we look at the average slop at the site, this translates to about half a km. The PP should be asked to change the parameters to increase this to more than a km at least.

It is also important to specify this distance between two projects because of the cumulative impacts of the project. The Siang basin study in its recent version, which will be discussed in the same 72nd EAC meeting has asked to change the FRL and TWL of some of the projects because they have not kept minimum distance of one kilometer between projects. The basin study report in section 12.1.3 stated “… is recommended that FRL of three projects viz. Tato II, Naying and Siyom Middle should be slightly reduced so that free flowing river stretches of 1 Km can be maintained between FRL and TWL of these four projects in cascade.”

Therefore Oju HEP PFR should clearly mention the distance between its TWL and FRL of the downstream project. EAC also should make this compulsory for all the projects in other river basins.

Form I and PFR contradictory about the Generating Units The Form I of Oju HEP in page 20 states that the installed capacity of 1850 MW will be generated through eight units of 231.25 MW each. But PFR on the other hand, in section 9 of page 8 states “The underground powerhouse, housing eight units of 225 MW each, is proposed on the right bank of the river Subansiri.” It is surprising to find such contradictions in the Form I and PFR of Oju project.

The PFR in page 13 again states “As mentioned earlier, project’s installed capacity has been fixed at 1850 MW and correspondingly, eight generating units of 231.25 MW, each, are proposed in the powerhouse.”

Huge Diversion of the River The Oju HEP will divert a huge length of the river. Page 1 of the PFR states, “The dam site is located at about 60 km upstream of Limeking and powerhouse site is located at about 40 km upstream of Limeking on the right bank of Subansiri river.” This implies that the river has been diverted for 20 km between the dam site and the power house (The head race length is 14.82 km). . This is a huge diversion of the river Subansiri which will have disastrous impacts on the health and ecosystem of the river. But neither the Form I nor the PFR provide what is the length of the river to be diverted for the project.

Subansiri carries significant amount of sediment The PFR report of Oju project in section 7.5.2 states “Since Subansiri River is expected to carry some amount of sediment during monsoons, effective management of sediment removal from the reservoir should be ensured.” Stating that the river carries some sediment is not correct since this river system is known for high sedimentation due to its location in the young Himalayan mountain range.

Reference to this can be found in the January-March, 2003 issue Ecologist Asia (page 12) which was focused on dams in northeast “The catchments of the Brahmaputra and its tributaries show significantly high rates of basin denudation especially after the great earthquake of 1950. The catchments of the Subansiri, Jia Bharali and the Manas along with the Dihang (Siang) are estimated to have experienced an average denudation of 73-157 cm./1000 years over just 24 years (1955-79). The increasing amounts of sediment and water yields downstream indicate an increase in sediment yield by a whopping 240% accompanied by an equally significant rise of nearly 120% in water yield during the period 1971-1979 between Tsela D’Zong (China) and Ranaghat (India).

Therefore first the sediment flow should be properly assessed.

Detailed and Thorough Options Assessment A detailed and through options assessment should be done for Oju project. There can be several other cost effective options for power generation in this area and options assessment should look into all such options. The options assessment should also look at whether the local people or the state needs such a huge capacity hydropower project.

It is important here to note that successful sub-megawatt capacity hydropower projects (Less than 1 MW) are currently under operation in Anjaw district of Arunachal Pradesh. (see – Anjaw shines in hydro power sector).

The TOR for the project does not include the following key aspects:

1. Issues related to cumulative impact assessment due to various components of the project and various projects in the basin.

2. The disaster vulnerability of the area on various aspects like landslides, earthquakes, floods, etc and how these will change with changing climate and how the project will change the disaster vulnerability of the area. There should be a separate chapter in EIA on this.

3. The project should do actual environment flow assessment and not just take the EAC norms as given. There should be separate chapter in EIA on this. The statement in Form 1 section 1.24 “Environmental Flows as per MOEF norms shall be released” is thus clearly premature and unwarranted. Eflows should be on daily changing basis and not seasonal averages.

4. Full Downstream social and environmental Impact Assessment

5. Impacts Peaking Power Operations

6. Assessment of impact of reservoir operation and mechanism to achieve transparent, accountable reservoir operation.

7. Impacts of Silt Management operations at various points of time and space.

8. Impacts of Tunneling and Blasting

9. Impacts of Mining of materials for the project.

10. Impacts of Backwater Effects of the reservoir in flood season

11. Impacts of Climate Change on dam

12. Impacts of the project on the adaptation capacity of the people in view of changing climate

13. Impact of peaking operation of the project on downstream areas and communities

No de-sanding chambers proposed in Silt Laden River The PFR in section 7.5.2 in page 7-5 states that “In this regard, it may be noted that no de-sanding chambers are proposed in the project in view of a relatively high dam with reservoir extending to almost 3.13 km.” Keeping no provision of de-sanding or de-silting chamber in the dam could have serious impacts on reservoir operations.

Form 1 undertaking not signed Page 2 of Form 1 is supposed to be an undertaking about the accuracy of information in Form 1, but there is no name, place or date for the signatory, all places are blank.

Poor reputation of consultants The PP has hired SNC Lavalin as consultant for DPR. However, SNC Lavalin has poor reputation in their country of origin (Canada[1]), globally[2] and even in Indian state of Kerala[3]. How dependable would the work of such an agency be is a big question mark.

Parag Jyoti Saikia (with inputs from Himanshu Thakkar)

[1] Out of  over 250 companies on World Bank’s current black listed from bidding on its global projects under its fraud and corruption policy, 115 are from SNC Lavalin and its affiliates, see:

[2] See:, the company has been banned by the World Bank due to corruption issues: “SNC-Lavalin, the engineering giant based out of Montreal that has now pretty much become a national (and international) embarrassment.” Its CEO has been arrested more than once for corruption charges.

[3] See:, there was a CBI inquiry in relation to hydropower projects related work and several politicians have been charge sheeted.

Arunachal Pradesh · brahmaputra · Cumulative Impact Assessment · Ministry of Environment and Forests · Siang

Cumulative Impact Assessment Study of Siang Basin in Arunachal Pradesh: Serious shortcomings; pro large hydro bias

Most of the major rivers in the North East India are largely free-flowing till date, which is a rarity in India and the world. Their basins are home to unbelievable ecological and cultural diversity. Main rivers in Arunachal Pradesh which form the mighty Brahmaputra are the Siang (the Yarlung Tsang Po), Dibang and Lohit, which meet at the trijunction to form Brahmaputra.

Massive hydropower projects are planned on these rivers in cascade. They will have irreversible destructive impacts on the society, forests, rivers, biodiversity, ecosystems, cultural identity and downstream Assam.

Hydropower Flood in Arunachal Pradesh Map: Neeraj Vagholikar, Sanctuary Asia
Hydropower Flood in Arunachal Pradesh
Map: Neeraj Vagholikar, Sanctuary Asia

Siang River alone has 44 dams planned along its entire length.

Yes, 44 dams. You have read it correctly. At least 44 dams in one sub basin of Brahmaputra River Basin. This is what was meant by MOU virus as Jairam Ramesh described it.

Siang River Basin The Siang river originates in the Chemayungdung mountain ranges which nearly sixty miles south-east of Mansarovar lake in the Mount Kailash range in Southern Tibet at an elevation of 5300 m. A spring called Tamchok Khambab spills from the glaciers which later gather breath and volume to become the Tsangpo, the highest river in world.  Tsangpo river flows 1625 km in Tibet parallel to the main range of Himalayas before entering India through Arunachal Pradesh.

Before entering India, the river passes Pi (Pe) in Tibet and suddenly turns to the north and northeast and cuts a course through a succession of great narrow gorges between the mountain Gyala Peri and Namjabarwa (Namcha Barwa) in a series of rapids and cascades. The river then turns south and southwest and flows through a deep gorge across the eastern extremity of the Himalayas with canyon walls that extends upward for 16,500 feet (5,000 meters) and more on each side.

The river enters Arunachal Pradesh near Gelling from where it is known as Siang. The total length of Siang River is 294 km till its point of confluence with Dibang and Lohit River. After entering India the river traverses approximately 197.0 km to join the Siyom river. From there the length of the river till Assam border is 86.3 km. Flowing further 10.6 km in Assam the river joins the confluence of Lohit and Dibang. From this point forward it flows as Brahmaputra river in Assam and traverses a distance of about 195 km up to the confluence of Subansiri river on its right bank. Further downstream it is joined by Kameng at Jamugurihat near Tezpur, after another 123 km.  From  here  it  travels  for  another  134  km  up  to Guwahati.

River Siang Photo from: Global Descents
River Siang Photo from: Global Descents

The elevation of Siang river catchment area ranges from 90 m to around 5800 m. The total catchment area of Siang river from its origin to its confluence with Lohit and Dibang rivers is 251,521 sq km. Out of this 236555.7 sq km area lies in Tibet. The total catchment area of Siang river in India upto its confluence with Lohit and Dibang rivers is 14965.30 sq km.    

A question arises here, what will be the condition of the 294 km long Siang river if the proposed 44 dams are being built on the river. The Siang river basin study has the answer for this which is actually alarming “Only 85.5 km (29%) of free flowing water regime of Siang river will be left out of its total course in India i.e.  294 km of lotic ecosystem will be converted into 208.5 km of lentic ecosystem altering the entire Siang river aquatic system which will adversely impact the aquatic biodiversity and seriously affecting fish populations and their migration behaviour.”(page 11.23)

Three dams on the main Siang will convert the free flowing river into a three-stepped reservoir, without ANY flowing length of the river! These dams alone will affect more than 18,000 hectares of forests! If all the dams are built, water level fluctuations in the downstream D’Ering Sanctuary will be more than 23 feet every single day in the winter and other non monsoon seasons!

82.26% of the Siang basin is under forest cover (more than 15,000 sq kms), it is rich in orchids (more than 100 species!), holds 16 species of rhododendrons, 14 species of Bamboos and 14 species of canes and overall 27 RET species and 46 endemic plant species. 25 (18%) mammalian species found are Schedule I of WPA (Wildlife Protection Act), while 26 are under Schedule II! There are 447 species of birds, of which 31 are Schedule I species. The single basin consists of 5 Important Bird Areas !!(IBAs)

Formation of River Siyom, which will have multiple dams in a cascade Photo from: Team BHP
Formation of River Siyom, which will have multiple dams in a cascade Photo from: Team BHP

This information has been collated by the CIA (Cumulative Impact Assessment)/ CCS (Carrying Capacity Study) of the Siang Basin, which was an attempt to look at the scale and cumulative impacts of projects in Siang holistically.

Has the CIA commissioned by Central water Commission and done by RS Envirolink Technologies done an objective, scientific, independent assessment?

SANDRP sent comments about this 2-volume study  with over 1500 pages to the Expert Appraisal Committee, Ministry of Environment and Forests which will be considering this basin study in its upcoming meeting on Feb 20-21, 2014. Submission below highlights that the study has very serious short comings and bias. The recommendation of dropping 15 (mostly small ones, all below 90 MW installed capacity) HEPs and re-configuring some others is welcome, but far from sufficient. The study itself is disappointing:

Projects planned in the Siang Basin Phot from CIA/ CCS of Siang Basin
Projects planned in the Siang Basin Phot from CIA/ CCS of Siang Basin


Time Line of Siang Basin Study

Feb 2010 Ministry of Water Resources constituted an Inter-Ministerial Group on the directions of Prime Minister’s Office with a view to evolve a suitable framework to guide and accelerate the development of hydropower in the North East and also to assess the impact of the massive hydropower development in Arunachal Pradesh on downstream areas in Assam
Nov 2010 EAC discussed TOR for the Siang Basin CIA
Dec 23, 2010 MoEF issues TORs for the Siang Basin CIA
April 2011 EAC discusses sampling locations for the CIA on request of CWC
Dec 2011 Work of CIA for Siang awarded to RSET Pvt Ltd
May 2012 RSET says draft interim report discussed by TAC, but there is no meeting of TAC in May 2012, minutes of March and July TAC meetings (the ones before and after May 2012) on CWC website also do not mention any such discussion.
Nov 2012 EAC discusses Draft Interim report
Aug 2013 Draft Final report submitted to CWC
Sept 2013 RSET says Draft final report discussed by TAC, but the minutes of the Sept 2013 meeting of the TAC obtained under RTI donot contain any reference to the Siang basin study
DEC 2013 Draft Final Report submitted to MoEF
Feb 17, 2014 Critique of the Draft Final report submitted by SANDRP to EAC
Feb 20, 2014 MoEF’s EAC to  discuss the Draft Final report


Chairperson and Members,

Expert appraisal Committee

Ministry of Environment and Forests


Subject: Serious inadequacies of Cumulative Impact Assessment (CIA) and Carrying Capacity Study (CCS) of Siang Sub-basin including Downstream Impacts

Respected Chairperson and Members,

We see from the agenda uploaded on the MoEF Website that Final Report of the Siang CIA/CCS Study commissioned by CWC and conducted by RS Envirolink Technologies Pvt Ltd will be discussed in the 72nd EAC Meeting to be held on 20-21 February 2014.

SANDRP has been analysing basin studies in the Western Himalayas and Brahmaputra Basin for some time now. Looking at the aggressive cascade hydropower development and its far reaching cumulative impacts, CIA/ CCS and Basin Studies should form the backbone of informed decision making by MoEF. Unfortunately, most studies being considered by the EAC are of a sub-standard quality and are shying away from addressing the cumulative impacts [1]. EAC itself is delinking appraisal of individual projects from basin studies, rendering the crucial process meaningless which is in violation of EIA notification of Sept 2006, wherein Form 1 Section 9 actually asks for cumulative impact assessment. Some of the recent orders of National Green Tribunal also make it CIA mandatory, thus making such delinking legally untenable.

Looking at the scale of ecological and social impacts of these projects and the significance of MoEF’s and EAC’s role, we urge the EAC to consider CIA/ CCS/ Basin Studies more seriously.

Main issues with Siang Basin Study include: (These are elaborated with reasons below)

1. No mention of social and cultural impacts!

2. Downstream impacts on Assam not studied in detail

3. Cumulative Disaster vulnerability, impact of projects on such vulnerabilities, Dam Safety Assessment, risk assessment not done

4. “Cumulative” Impacts not assessed on several aspects

5. Non-compliance with critical recommendations by the EAC:

a. Study is not compatible with similar studies done worldwide

b. No suggestions about ramping to reduce downstream impacts

c. No recommendation on free flowing length between two projects

d. No mention of cumulative impact on sediment regime

e. No mention of impact of road construction

f. BBM for eflows not used, despite agreeing to use it before EAC

g. Impact of Sand mining, boulder mining not conducted

h. Impact of specific projects not clearly studied

6. Eflows, one of the most significant issues, handled erroneously: NO ACTUAL ASSESSMENT OF E-FLOWS REQUIREMENTS AS REQUIRED BY TORs

7. No mention of Climate Change, reservoir emissions vis-à-vis cumulative impacts of such massive scale, how the projects would affect the adaptation capacity of the communities and region in the context of climate change

8. No stand taken on three mega projects on Siang Main Stem and other big hydro projects

9. No conclusion about how much length of the river is to be compromised

10. Number of sampling locations: TOR not followed

11. Source of information not given

12. Inconsistency, contradictions in listing of flora-fauna

13. Unsubstantiated advocacy: going beyond the TOR & mandate

14. Other inadequacies of CIA

15. Study should not be finalised without credible Public consultation across the basin.

Division of the Siang Basin into sub basins Phot from : CIA/ CCS Report of the Siang Basin
Division of the Siang Basin into sub basins Phot from : CIA/ CCS Report of the Siang Basin


1. No mention of social and cultural impacts! In the entire basin study, there is no mention of social and cultural impacts by these 44 projects which will together submerge more than 21,000 hectares of forests and affect the entire Siang Basin adversely. Needless to say, local communities depend heavily on the basin resources like fish, medicinal and food plants, timber varieties for their livelihoods. For example, more than 2000 hectares of multi-cropped, irrigated rice fields will be submerged by Lower Siang Project alone.

Adi Community that will be affected by the dams on Siang Photo with thanks from : Kaushik Shil
Adi Community that will be affected by the dams on Siang Photo with thanks from : Kaushik Shil

The CIA/CCS study needs to be re-conducted, in which social and cultural cumulative impacts are assessed with participation of local communities and downstream communities from Arunachal Pradesh and Assam. It may be remembered that Public Hearing of Lower Siang (in the latest instance, slated to be held on 31st January 2014) had to be cancelled due to a number of procedural issues, and also opposition from local residents [2]. It is incomprehensible how the CIA Study has no assessment of impacts on communities!

2. Downstream impacts on Assam not studied in detail The study assesses impacts specifically on Dibrugarh, Bokaghat (Kaziranga) and Guwahati. However, there are several villages, settlements, tea estates, agriculture, forests etc., on the Right Bank of Siang in Assam after Pasighat. This includes a major part of Dhemaji District of Assam. Impact on this region needs to be assessed. There has been opposition to Siang Dams from places like Jonai from Dhemaji, which have been ignored.[3] 

Meeting protesting against Public Hearing of 2700 MW Lower Siang HEP Photo: Echo of Arunachal
Meeting protesting against Public Hearing of 2700 MW Lower Siang HEP Photo: Echo of Arunachal

According to the model used, the chainage for assessing impacts at D’Ering Sanctuary is between 20-33 kms from Lower Siang Dam. The next chainage is at 102 kms at Dibrugarh. Impacts on the stretch between D’Ering and Dibrugarh, for nearly 70 kilometres are simply not assessed! What can be reason behind this?

Level fluctuations at D’Ering Sanctuary, with Lower Siang, Middle Siyom and Upper Siang Projects is to the tune of 7.2 meters (23.66 feet!!) in lean season. This highlights the need to study impacts on the intermediate zone in Assam between Dering Sanctuary and Dibrugarh. The Study should not be accepted without these assessments.

3. Cumulative Disaster vulnerability, impact of projects on such vulnerabilities, Dam Safety Assessment, risk assessment not done

Upper Siang Stage I, Stage II and Lower Siang are huge projects with direct impact on downstream state. Even as issues of dam safety and risk assessment have gained high significance in Assam as can be seen in Lower Subansiri protests, the basin study/CIA does not include a word on dam safety, cumulative risk assessment, risk of landslips and landslides, seismic zones of projects, past earthquakes in the region, possible mitigation measures, disaster management, etc. There is no assessment of baseline situation about disaster vulnerability of the region and how the projects will change that. By its nature, a CIA/CCS/ basin study is best placed to assess these impacts.

Lanslides are a common feature of this region. Pic shows Yinkiong in Siang II Sub basin where several projects are planned. Photo: Team BHP
Lanslides are a common feature of this region. Pic shows Yinkiong in Siang II Sub basin where several projects are planned. Photo: Team BHP

These points have been raised by KMSS, Assam and others. The Uttarakhand disaster of June 2013 underlines this and even the Supreme Court of India has asked for an assessment of how hydropower projects contributed to disaster in Uttarakhand. Looking at Uttarakhand Disaster as well as protests from downstream Assam where dam safety is a major issue, dam safety needs to be addressed in the CIA/ CCS. In the absence of all this, projects will not be allowed by communities, as can be seen with Lower Subansiri and Lower Siang.

4. Cumulative impacts not assessed on several aspects The study has a sketchy section (Chapter 11) on Cumulative impact assessment.

The minutes of 62nd EAC meeting noted, “The main objective of the study is to bring out the impact of dams being planned on the main Siang River and its seven tributaries on terrestrial and aquatic ecology, plant and animal biodiversity, including wild life, hydrology of the basin, etc.” (Emphasis is as in original.) However, the study has not placed emphasis on assessing these impacts.

Yar Gyap Chu: a River and basin which holds high religious significance for the Buddhists Photo: Kaushik Shil
Yar Gyap Chu: a River and basin which holds high religious significance for the Buddhists Photo: Kaushik Shil

Moreover, the study does not attempt to assess cumulative impacts of all the projects due to:

  • Blasting and Tunnelling: This is not mentioned even once in the entire study! When the disastrous impacts of blasting, tunnelling and related activities are fresh in our minds w.r.t Uttrakhand and Himachal Disasters, it is incomprehensible to see that this section is not mentioned at all in the basin study!
  • Community resources: No mention on loss of agricultural lands, homesteads, displacement, loss of forest rights, etc.
  • Infrastructure development: No mention of the impact of workers colonies, buildings on the society, landscape and cultural aspects, etc.
  • Greenhouse gas Emissions: Considering submergence of more than 20,000 hectares of dense to very dense forests and building of a large number of reservoirs in tropical climate, cumulative impacts on green house gas emissions should have been assessed.
  • Biodiversity, RET Species, Deforestation: While the report deals with these issues very sketchily, there is no statement as to what will be the cumulative impact of 44 projects on the above issues.

5. Non-compliance with critical recommendations by the EAC Interim basin study was discussed in the 62nd EAC meeting in November 2012. The EAC had given some important recommendations at that stage to be included in the study. However, most of the recommendations have not been complied with, these include:

  • Study is not compatible with similar studies done worldwide: EAC had specifically recommended compatibility with global studies. However, Siang CIA is not compatible with any global Basin and Cumulative impact Assessment Study. A Cumulative Impact Assessment is a multi-stake – holder process that assesses the cumulative and indirect impacts as well as impact interactions of the proposed dam or set of dams, as well as existing and planned projects from other sectors, on ecosystems, communities, and identified Valuable Ecosystem Components (VECs) within a specific spatial and temporal boundary. [4]
  • No suggestions about ramping to reduce downstream impact: EAC had specifically asked for ramping study with reference to downstream impacts. However, ramping studies are not done at all, although downstream impacts of the projects in isolation as well as together are huge. 
  • No recommendation on free flowing length between two projects Although Upper Siang I, Upper Siang II and Lower Siang have no free flowing stretch between each other, the study refrains doing any assessments or from making any recommendations in this regard, contrary to EAC’s recommendation. 
  • No mention of cumulative impact on sediment regime 44 projects with several mega reservoirs will have a profound impact on the sediment regime of the rivers as well as downstream impacts thereof. EAC had specifically asked to include sediment balance and impact, which is not discussed in the report. 

The minutes of 62nd meeting of EAC says: “The Consultants were also asked to study and recommend on silt management considering “no dam” and “with dam” scenario as silt substantially impact the ecology and cause sedimentation particularly when its velocity is affected d/s due to construction of dam.” No such study has been conducted. In fact globally, sediment balance on cascade projects is a crucial element of study, which is completely left out in the present study. 

  • No mention of impact of road construction Roads and related activities like deforestation, slope destabilisation, blasting, mining, muck dumping, all the cumulative impacts of peaking operation (needs to be done comprehensively, including the limitations that such operation of upstream projects will impose on downstream projects), etc have a critical impact on fragile geology. Role of roads for hydel projects was significant in Uttarakhand Tragedy in June 2013. EAC had specifically asked for “Impacts due to construction of approach roads”. This point is not touched upon in the report. 
  • BBM for eflows not useddespite agreeing to use it in front of EAC Although the consultant agreed in the 62nd meeting that BBM will be used to assess eflows regime,[5] at the insistence of the EAC, in reality BBM has not been used in the study. The reasons given [6] that BBM is a “prescriptive approach”, “it takes too much time” and “only stakeholder in the basin is river and fish” is wrong, shocking and unacceptable.

The study forgets about the people, biodiversity and other stakeholders. Requirements of BBM were known at the time consultant agreed to use this methodology before the EAC. Is fluvial geomorphology, cultural practices, hydrological requirements and sediment balance not important blocks of BBM study? 

  • Impact of Sand mining, boulder mining not conducted EAC had specifically asked for this study. This is critical as mining of sand and boulders from river bed has severe impact on riverine ecology, bed stability, erosion, flow velocity, etc. However, the study has not even mentioned this issue. 
Yargyap Chu or teh Medicinal RIver Photo: Team BHP
Yargyap Chu or the Medicinal RIver Photo: Team BHP
  • Cumulative Impacts of projects on biodiversity in sub-basins not clearly studied While the study has done impressive job in inventorysing ecological attributes of 11 sub basins, it has fallen woefully short in clearly communicating the individual and cumulative impacts of projects on Valued Ecosystem Components (VECs). This reduces practical application of the report. EAC had brought this up during the 62nd meeting. 
  • Length of rivers to be assessed for downstream studies As per the minutes of the 43rd meeting of EAC held in Nov 2010 the report was to recommend: “What may be criteria for downstream impact study in terms of length of the river downstream to the tail water discharge point and what may be the parameters of such a study”.

The same EAC meeting recommended: “If the states do not change their policy of allotting elevation-wise river reaches for hydropower development, what criteria the EAC may adopt in restricting the river reach for hydropower development. Alternatively, what should be the clear river length of uninterrupted flow between the reservoir tip at FRL of a downstream project and the tail water discharge point of the immediate upstream project.”

“For peaking stations, what extent of diurnal flow variation may be considered safe for the aquatic life. There are examples where the release is drastically reduced during the long time for reservoir filling and huge discharge flows through the river during the few hours of peak power generation. This is detrimental to the aquatic environment of the downstream stretch of the river.”

“For muck disposal, what may be minimum distance that must be maintained between the outer boundary of the muck disposal sites and the river bank.”

6. Eflows, one of the most significant issues handled erroneously: NO ASSESSMENT OF E-FLOWS REQUIREMENTS The CIA has not done assessment of e-flows requirements at various locations keeping in mind the upstream projects. The very crude assumption it has made is by dividing the entire basin in Mahseer and Trout Zone and assuming certain water depths for these fish in lean, monsoon and non-lean, non-monsoon months. Several fisheries scientists do not support this classification or accept these two species alone as representing the ecosystem. The study assumes 50 cms water depth for Mahseer and 40 cms depth for Trout in lean season.[7] Then flows for maintaining that particular depth are calculated and recommended. Added criteria is that depth should not be less that 50% pre-project river depth. 

Luxuriant Biodiversity of the Siang basin Photo: Team BHP
Luxuriant Biodiversity of the Siang basin Photo: Team BHP

Here it is worth quoting the minutes of 62nd meeting of EAC:

“The EAC asked the Consultants to take comprehensive view of the environmental flow assessment and make final recommendations for each stretch. Committee asked to study international literature available on the subject and use the best suitable methodology for this exercise suiting to Indian conditions. The Consultants said that most appropriate method such as Building Block Methodology would be used by them. Detailed habitat simulation modelling for the entire year needs to be considered so that flow release requirement can be established not only for lean season but also for monsoon season and other months… The Consultants while submitted that public hearing as such is not a part of the study as per ToR, informed that BBM entails expert and stakeholder‟s consultations and would be followed.”

This has clearly not been done.

This approach is incorrect on various counts:

  • The habitat requirements of Mahseer and Snow Trout are higher than the assumed 0.5 m and 0.4 m. This has been confirmed by several fisheries scientists. The WII study on Upper Ganga Projects recommends a minimum of water depth of 1 meter for adult Mahseer (Tor species) (Table 7.6, Page 148) and at least more than 50 cms for Trouts (Schizothorax sps) (Table 7.8, Page 150). Incidentally these tables from WII Cumulative Impact Assessment have been used in the report without stating the source or credit. SANDRP has interacted with several fisheries experts who claim that 0.5 meters is a completely inadequate depth for adult Mahseer.
  • This faulty assumption has led to low eflows recommendations of 15% of average flows in non-lean non-monsoon months for Heo and Tato I Projects, this is lower even that EACs norms. This assessment and recommendations are clearly unacceptable.
  • The criteria of 50% water depth wrt pre-project depth is arbitrary and without any scientific justification. For Himalayan rivers with a stable hydrograph like Siang, 50% depth reduction is very high. As can be seen from Eflows chapter, after 50% depth reduction, most river stretches have less than 100 cms depth, which is just about the minimum depth required for an adult Mahseer or a spawning snow trout. However, Mahseer and trouts are abundant in these rivers. This just indicates the problems behind 50% water depth criteria. This should not be accepted.
  • The entire eflows discourse is not based on assessment of environment flows for various objectives and ignores most critical requirements.

    Division of the Basin into Trout and Mahseer Zones Photo: From CIA/ CCS Report of Siang Basin
    Division of the Basin into Trout and Mahseer Zones Photo: From CIA/ CCS Report of Siang Basin

7. No mention of Climate change In the entire study, there is no mention of climate change, how changing climate would affect the rivers and projects and how project construction would add to climate change impacts and how they will reduce the adaptation capacity of the people and environment to cope with the changing climate. Deforestation to the scale of 21000 hectares of thick forests and complete loss of a biodiversity rich free flowing river has strong impacts in the context of climate change and these need to be assessed.

8. No stand taken on three mega projects on Siang Main Stem and other big hydro projects Three mega projects on Siang Main stem, namely the 6000 MW Upper Siang I, 3750 MW Upper Siang Stage II and 2700 MW Lower Siang will have a huge destructive impact on the entire ecology and society of the region. These three projects together will submerge 18,100 hectares of dense forest area and will convert entire river length between these projects: 208.5 kilometers, into unbroken sequence of reservoir-dam-reservoir-dam-reservoir-dam, with no flowing river between two consecutive projects. The study has not even attempted assessment of length of flowing river required between the projects and eflows allocation for this stretch.

L Section of the Siang River with 3 mega projects which do not leave any flowing river between them. Photo from: CIA/ CCS Report of the Siang Basin
L Section of the Siang River with 3 mega projects which do not leave any flowing river between them. Photo from: CIA/ CCS Report of the Siang Basin


Oppsition to Public Hearing of 2700 MW Lower Siang Project Photo: Echo of Arunachal
Oppsition to Public Hearing of 2700 MW Lower Siang Project Photo: Echo of Arunachal

These projects in a cascade, destroying a complete flowing river are against the principle of sustainable development and even EAC’s minimalist norm of 1 km of flowing river between projects. A CIA/ CCS study should have raised this issue strongly as these projects are undoing most of the other recommendations. However, the study refuses to take an independent stand against these projects and fails its mandate of being an independent study. 

Yamne Basin, claimed to host highest biodiversity in Siang is planned to have 4 projects back to back! Photo: Abor Country Travels
Yamne Basin, claimed to host highest biodiversity in Siang is planned to have 4 projects back to back! Photo: Abor Country Travels

Similarly the study does not take stand on other big hydropower projects proposed in the basin. Most of the projects it has recommended to be dropped are relatively smaller projects, none are big ones. This shows bias of the consultants. The report is also not in consistent in its recommendations. 

Positive suggestions: The study recommends dropping 15 projects and keeping some tributaries free from any hydel development. It also calls for including small hydel projects under the ambit of EIA. These suggestions are important and should be accepted. EAC should immediately ask MoEF to recommend changes in the EIA notifications to include all hydro projects above 1 MW. 

The study has also asked for change in parameters of Tato II, Hirong, Naying and Siang Middle HEPs so that at least 1 km of river is left flowing between them. This is welcome and EAC should accordingly ask for changes in these projects. But the report has not done any study in this regard. 

9. No conclusion about how much length of the river is to be compromised One of the TORs of the study include, as per the minutes of the 43rd meeting of EAC held in Nov 2010: “Considering the total length of the main river in the basin and the HEPs already existing and planned for future development, how many more HEPs may be allowed to come up. In other words, how much of the total length of the river that may be tunneled inclusive of the tunnelling requirement of all the projects that have been planned for development so that the integrity of the river is not grossly undermined.” (Emphasis added.) The report does not do an assessment on this. The B K Chaturvedi committee had recommended that not more than 50% of the river can be compromised. However, this report was to study this aspect, but has neither studied this, nor done analysis or reached any conclusion. 

10. Number of sampling locations The minutes of 49th meeting of EAC held in April 2011 concluded that the number of sampling locations will be decided based on this criteria: 3 sites for project with over 1000 MW installed capacity, 2 sites for projects with 500-1000 MW installed capacity and one site for projects below 500 MW installed capacity. In addition 2-3 locations will be selected in the downstream areas. 

Menchuka_Team BHP

If we go by this criteria, and considering 44 planned projects listed in the CIA, there should have been 15 locations for 5 projects with capacity 1000 MW or above, 4 for two projects with 500-1000 MW capacity and 37 for projects below 500 MW capacity, in addition to the locations in downstream areas. The CIA has not followed these directions from EAC, else sampling locations would have been about 60 and not 49 as included in the report. 

11. Source of information not given Several annexures in Vol II (this too should have been put up on EAC website, but has not been, we got it from other sources), including Annex I says that it is prepared from “PREPARED FROM SECONDARY DATA & FIELD SURVEYS”, but which information has been obtained from field surveys and which information is obtained from which secondary source is not given. In absence of this it is difficult to verify the claims. 

12. Inconsistency, contradictions in listing of flora-fauna

– In volume II, Annex I titled “LIST OF PLANT SPECIES REPORTED FROM SIANG BASIN”, which is supposed to include data from secondary sources and field surveys lists 1249 angiosperms and 11 gymnosperms. However, the pteridophytes listed in Annex II titled “LIST OF PLANT SPECIES RECORDED FROM DIFFERENT SUB BASINS OF SIANG DURING FIELD SAMPLING” do not find mention in Annex I or Annex III a/b/c.

Out of 11 Gymnosperms listed in Annex I, only two figure in Annex II, rest do not get listed in any of the sub basins.

– The species Dicliptera bupleuroides and Phlogacanthus thyrsiflorus listed in Annex 1 Angiosperms do not get listed in any of the sub basins.

Section 4.1.4 says Paphiopedilum fairrieanum is an endangered and Cymbidium eburneum is an endemic and vulnerable orchid species in Siang basin, however, these species do not get listed in any sub-basins in Annexure II or in any season in Annexure III. Same is the case with endemic orchid species of Siang basin, namely Calanthe densifloraDendrobium cathcartiiD hookerianumGaleola falconeriLiparis plantaginea and Paphiopedilum fairrieanum.

– Similarly among the Rhododendron species, threatened species like Rhododendron boothii, threatened species like Rhododendron falconeri, newly discovered and critically endangered species like Rhododendron mechukae (even though it was found in Yargyap Chhu sub basin), Rare species like Rhododendron arizelumRhododendron dalhousieaevar. rhabdotum,Rhododendron kenderickii, and R edgeworthii are not found in Annex II or III.

Rhododendron Species of Siang Basin Photo: Abor Country Travels
Rhododendron Species of Siang Basin Photo: Abor Country Travels

Endemic cane species Calamus leptospadix also do not figure in Annex II or III.

– The CIA says, “The Siang basin as discussed above is also very rich in floristic resources and there are still number of areas in the basin which are either under-explored or yet to be explored”, however, a CIA is supposed to make recommendation how to ensure that such areas are explored before any more projects are taken up, but this report makes no recommendation in this regard.

– The CIA says that 17 Near Threatened (regional level) medicinal plants, 46 endemic species and additional 55 endemic species are reported in Siang basin, but CIA neither gives list of them, nor locations, how these will be affected by hydropower projects or recommendations to conserve them.

– The scope of study given in Annex 1, Vol. I says: “Preparation of comprehensive checklist of flora (Angiosperms, Gymnosperms, Lichens, Pteridophytes, Bryophytes, Fungi, Algae etc.) with Botanical and local name.” However, we do not find the local names listed.

The situation with respect to fauna species is no different, with similar inconsistencies, lack of specific sub-basin wise situations and recommendations to conserve them. This is true in case of mammals, birds, butterflies, amphibians, reptiles, inspects as also aquatic biodiversity. While the report makes some impressive general statements, but is found to be lacking in specifics mentioned above.

This sample list of inconsistencies and gaps shows that there are serious problems in these lists and the consultant should be asked to remove all these inadequacies. There is also need to get these lists peer reviewed by credible independent experts like those from WII.

13. Unsubstantiated advocacy: going beyond the TOR & mandate The CIA says in last para in section 12.3 titled “Downstream Impacts”, “Keeping the substantial storage requirement in Siang, storage projects in Siang needs to be re-configured, which may lead to merging of Siang Upper Stage I and II into single project to create storage.” There are several other such sentences in this section and elsewhere. This is uncritical acceptance of CWC assertions and is an advocacy for more storage projects in the name of flood moderation. This is clearly uncalled for in a CIA report and such uncritical acceptance of CWC assertions is also not what is expected from a CIA. In any case, this is also beyond the mandate of the CIA.

14. Other inadequacies of CIA

– The CIA does not contain the TOR, the scope of the study given Annex 1 of Vol I is not the TOR.

– 49th EAC meeting had asked for inclusion of Assam Experts in the study, but the study does not mention this.

– The 43rd EAC meeting held in Nov 2010 had asked for inclusion of assessment of the impacts of the projects on wetlands, floodplains, river morphology, sediment transport/ erosion/ deposits, impact on human activities and livelihoods and recommend necessary measures in these regard. The report mentions all these aspects, but fails to assess these impacts and make necessary recommendations.

– The Preface of the CIA claims that the TAC reviewed the draft interim report in May 2012 and draft final report in Sept 2013. We have checked the minutes of the TAC meetings and find that in May 2012 there was no TAC meeting. The 114th TAC meeting happened in March 2012 and 115th TAC meeting happened in July 2012, neither of the minutes include any mention of Siang basin study.

– The Sept 2013 meeting also did not include this report in its agenda. The report seems to be making false claims in this regard, they should be asked to provide minutes of the TAC meeting where this was discussed and what were the outcomes.

15. Study should not be finalised without credible Public consultation across the basin A comprehensive Siang Basin Study will give a cumulative picture of impacts on basin and on basin residents, including downstream population in Assam. The study is supposed to include important findings, which are separate from individual EIA reports. Even MoEF’s Strategic 12th Five Year Plan notes: 

Paddy feilds in Siang Basin. Agriculture finds no place in the CIA Photo: Kaushik Shil
Paddy feilds in Siang Basin. Agriculture finds no place in the CIA Photo: Kaushik Shil

“Of late, the limitations of project-level EIA are being realized internationally. Project EIAs react to development proposals rather than anticipate them, so they cannot steer development towards environmentally “robust” areas or away from environmentally sensitive sites. Project EIAs do not adequately consider the cumulative impacts caused by several projects or even by one project’s subcomponents or ancillary developments. The new trend is to address environmental issues earlier in planning and policy making processes. This could be done through cumulative impact assessment.” 

However, such a study cannot be complete without consultations held across the basin in a credible way with full information to the communities in the language and manner they can understand. The study should not be accepted without a credible process of Public hearing [8].

CONCLUSION We would like to urge the EAC NOT TO CONSIDER INDIVIDUAL PROJECTS UNLESS THE CIA/CCS Study is APPROVED through a participatory process. In Siang basin, the EAC has already granted EC to 2 projects, Scoping clearance to 16 projects (of which PH has been held for 8 projects) and nine projects will not need EC as they are below 25 MW. This renders the whole exercise of CIA/CCS meaningless!

We urge the EAC to consider all projects from Siang Basin only after CIA-CCS is finalised and keep the scoping and environmental clearances of projects in abeyance till then. 

Prayer Flags in Siang basin Photo: Team BHP
Prayer Flags in Siang basin Photo: Team BHP

Looking forward to you point-wise response,

Yours Sincerely,

Parineeta Dandekar, Himanshu Thakkar SANDRP

(with inputs from Parag Jyoti Saikia)

[1] SANDRPs assessment of Lohit Basin Study, Bichom Basin Study, Subansiri Basin Study and Upper Ganga Cumulative Impact Assessment.
[2] – This news was covered widely in the media – Arunachal Pradesh Groups Ask MoEF to Cancel Illegal Public Hearing of Lower Siang 2,700 mw Lower Siang Hydro Electric project runs into rough weather ,  GreenTalk: Activists to protest public hearing for dam on Arunachal’s Lower Siang river,  Protests against Siang dam,  Anti-dam stir hits Arunachal too, AASU,  TMPK oppose move on Lower Siang project,  Public hearing for Lower Siang project opposed,  Several organisations demand scrapping of Lower Siang project.
[3] Jonai meet opposes Arunachal dams
[4] Some such relevant benchmark norms include:
The World Commission on Dams Report, Nov 2000
International Rivers, Dam Standards: A Rights Based Approach, January 2014
The European Commission’s Guidelines for the Assessment of Indirect and Cumulative Impacts as well as Impact Interactions (1999)
The U.S. NEPA Analysis Guidance Manual (2007)
The Canadian Environmental Assessment Agency’s Cumulative Effects Assessment Practitioners Guide (1999)
– International Finance Corp’s (The World Bank Group) “Good Practice Note on Cumulative Impact Assessment and Management”, Jan 2013
– The World Bank’s “Sample Guidelines: Cumulative Environmental Impact Assessment for Hydropower Projects in Turkey”, Dec 2012
[5] “It was informed that BBM would be applied in addition to other applicable methodologies for working out EFR. The Consultants while submitted that public hearing as such is not a part of the study as per ToR, informed that BBM entails expert and stakeholder’s consultations and would be followed.” 62nd EAC Meeting, November 2012
[6] Section 9.9 of the CIA CCs Report
[7]“ To assess the minimum environment flow requirement in lean season a criteria has been defined that projects in the Mahseer zone needs to provide a minimum 0.5 m average depth in the initial reach studied, and for projects in the trout zone this depth is considered as 0.4m.” (Section 9.6.1 Environmental Flows Assessment in Lean Season)
[8] Himachal Pradesh Government had conducted such a Public Hearing on Satluj Basin Study recently

Post Script:

A good report on the Siang Basin CIA: Damn that river Author: Karthik Teegalapalli Posted on: 13 Oct, 2014:

Arunachal Pradesh · Environment Impact Assessment · Expert Appraisal Committee · Hydropower

Subansiri Basin Study – Another Chapter of Environment Subversion in Northeast

The Study The study has been done by IRG Systems South Asia Private Limited (, a subsidiary of US based IRG Systems) and[i]. It is supposed to be a Cumulative Impact Assessment of 19 HEPs planned in the basin, out of which PFRs of 7 are available, DPR of two, and one of which, the 2000 MW Subansiri Lower HEP is under construction.

Subversion of Environment Governance in the Subansiri basin While looking at this basin study, the subversion of environment governance in Subansiri basin this very millennia should be kept in mind. A glimpse of it is provided in Annexure 1. In fact, one of the key conditions of environmental clearance to the 2000 MW Lower Subansiri HEP was that no more projects will be taken up in the basin upstream of the Lower Subansiri HEP, which essentially would mean no more projects in the basin, since LSHEP is close to the confluence of the Subansiri River with Brahmaputra River. That condition was also part of the Supreme Court order in 2004. The need for a carrying capacity study was also stressed in the National Board of Wild Life discussions. We still do not have one. In a sense, the Subansiri basin is seeing the consequences of that subversion.

Map of Subansiri RIver Basin  Source:
Map of Subansiri RIver Basin

Information in public domain not known to consultants The report does not even state that Middle Subansiri dam have also been recommended TOR in 41st EAC meeting in Sept 2010. This project will require 3180 ha of land, including 1333 Ha forest land, and 2867 ha area under submergence. Even about Upper Subansiri, the consultants do not know the area of forest land required (2170 ha). So the consultants have not used even the information available in public domain in EAC meetings.

Study based on flawed and incomplete Lohit Basin Study The Study claims that it is based on Lohit Basin Study done by WAPCOS. Lohit Basin Study is an extremely flawed attempt and does not assess cumulative impacts of the cascade projects. Civil society has written about this to the EAC and the EAC itself has considered the study twice (53rd and 65th EAC Meetings), and has not accepted the study, but has raised several doubts. Any study based on a flawed model like Lohit Basin Study should not be acceptable.

A house in the upstream of Subansiri River  Source:
A house in the upstream of Subansiri River

No mention of Social impacts Major limitation of the study has been absolutely no discussion on the severe social impacts due to cumulative forest felling, flux of population, submergence, livelihoods like riparian farming and fishing, etc. Though this has been pointed out by the TAC in its meeting and field visit, the report does not reflect this.

Some key Impacts Some of the impacts highlighted by the study based on incomplete information about HEPs are:

Þ    The length of the river Subansiri is 375 km up to its outfall in the Brahamaputra River. Approximately 212.51 km total length of Subansiri will be affected due to only 8 of the proposed 19 HEPs in Subansiri River basin.

Þ    Total area brought under submergence for dam and other project requirements is approx. 10, 032 ha of eight proposed HEPs. The extent of loss of forest in rest of the 9 projects is not available.

Þ    62 species belonging to Mammals (out of 105 reported species), 50 Aves (out of 175 reported species) and 2 amphibians (out of 6 reported species) in Subansiri Basin are listed in Schedules of Wildlife Protection Act, 1972 (as amended till date).

Þ    99 species belonging to Mammals (out of 105 reported species), 57 species belonging to Aves (out of 175 reported species), 1 Reptilian (out of 19 reported species), 2 Amphibians (out of 6 reported species), 28 fishes (out of 32 reported species), 25 species belonging to Odonata of Insecta fauna group (out of 28 reported species) are reported to be assessed as per IUCN’s threatened categories.

Even this incomplete and partial list of impacts should give an idea of the massive impacts that are in store for the basin.

Cumulative impacts NOT ASSESSED Specifically, some of the cumulative impacts that the report has not assessed at all or not adequately include:

1. Cumulative impact of blasting of so many tunnels on various aspects as also blasting for other project components.

2. Cumulative impact of mining of various materials required for the projects (sand, boulders, coarse and fine granules, etc.)

3. Cumulative impact of muck dumping into rivers (the normal practice of project developers) and also of also muck dumping done properly, if at all.

Subansiri River in the Upper Reaches  Source: Lovely Arunachal
Subansiri River in the Upper Reaches
Source: Lovely Arunachal

4. Changes in sedimentation at various points within project, at various points within a day, season, year, over the years and cumulatively across the basin and impacts thereof.

5. Cumulative impact on aquatic and terrestrial flora and fauna across the basin due to all the proposed projects.

6. Cumulative impact of the projects on disaster potential in the river basin, due to construction and also operation at various stages, say on landslides, flash floods, etc.

7. Cumulative dam safety issue due to cascade of projects.

8. Cumulative change in flood characteristics of the river due to so many projects.

9. Cumulative impacts due to peaking power generation due to so many projects.

10. Cumulative sociological impact of so many projects on local communities and society.

11. Cumulative impact on hydrological flows, at various points within project, at various points within a day, season, year, over the years and cumulatively across the basin and impacts thereof. This will include impacts on various hydrological elements including springs, tributaries, groundwater aquifers, etc. This will include accessing documents to see what the situation BEFORE project and would be after. The report has failed to do ALL THIS.

12. Impact of silt laden water into the river channel downstream from the dam, and how this gets accumulated across the non-monsoon months and what happens to it. This again needs to be assessed singly and cumulatively for all projects.

13. Impact of release of silt free water into the river downstream from the power house and impact thereof on the geo morphology, erosion, stability of structures etc, singly and cumulatively.

14. Impact on Green House Gas emissions, project wise and cumulatively. No attempt is made for this.

15. Impact of differential water flow downstream from power house in non-monsoon months, with sudden release of heavy flows during peaking/ power generation hours and no releases during other times.

16. Cumulative impact of all the project components (dam, tunnels, blasting, power house, muck dumping, mining, road building, township building, deforestation, transmission lines, etc.,) for a project and then adding for various projects. Same should also be done for the periods during construction, operation and decommissioning phases of the projects.

17. Cumulative impact of deforestation due to various projects.

18. Cumulative impact of non compliance of the environment norms, laws, Environment clearance and forest clearance conditions and environment management plans. Such an assessment should also have analysed the quality of EIA report done for the Subansiri Lower hydropower project.

Wrong, misleading statements in Report There are a very large number of wrong and misleading statements in the report. Below we have given some, along with comment on each of them, this list is only for illustrative purposes.

Sr No

Statement in CIA


1 “During the monsoon period there will be significant discharge in Brahmaputra River. The peaking discharge of these hydroelectric projects which are quite less in comparison to Brahmaputra discharge will hardly have any impact on Brahmaputra.” This is a misleading statement. It also needs to be assessed what will be the impact on specific stretches of Subansiri river. Secondly, the projects are not likely to operate in peaking mode in monsoon.
2 “However, some impact in form of flow regulation can be expected during the non-monsoon peaking from these projects.” This is not correct statement as the impact of non-monsoon peaking is likely to be of many different kinds, besides “flow regulation” as the document describes.
3 “Further, during the non-monsoon period the peaking discharge release of the projects in upper reaches of Subansiri basin will be utilized by the project at lower reaches of the basin and net peaking discharge from the lower most project of the basin in general will be the governing one for any impact study.” This is again wrong. What about the impact of such peaking on rivers between the projects?
4 “The construction of the proposed cascade development of HEPs in Subansiri basin will reduce water flow, especially during dry months, in the intervening stretch between the Head Race Tunnel (HRT) site and the discharge point of Tail Race Tunnel (TRT).” This statement seems to indicate that the consultants have poor knowledge or understanding of the functioning of the hydropower projects. HRT is not one location, it is a length. So it does not make sense to say “between HRT and the discharge point of TRT”.
5 “For mature fish, upstream migration would not be feasible. This is going to be the major adverse impact of the project. Therefore, provision of fish ladder can be made in the proposed dams.” This is simplistic statement without considering the height of the various dams (124 m high Nalo HEP dam, 237 m high Upper Subansiri HEP dam, 222 m high Middle Subansiri HEP dam), feasibility of fish ladders what can be optimum design, for which fish species, etc.
6 “…water release in lean season for fishes may be kept between 10-15% for migration and sustaining ecological functions except Hiya and Nyepin HEP. Therefore, it is suggested that the minimum 20% water flow in lean season may be maintained at Hiya and Nyepin HEP for fish migration.” This conclusion seems unfounded, the water release suggested is even lower than the minimum norms that EAC of MoEF follows.

Viability not assessed The report concludes: “The next steps include overall assessment of the impacts on account of hydropower development in the basin, which will be described in draft final report.”

One of the key objective of the Cumulative Impact assessment is to assess how many of the planned projects are viable considering the impacts, hydrology, geology, forests, biodiversity, carrying capacity and society. The consultants have not even applied their mind to key objective in this study. They seem to assume that all the proposed projects can and should come up and are all viable. It seems the consultant has not understood the basic objectives of CIA. The least the consultant could have said is that further projects should not be taken up for consideration till all the information is available and full and proper Cumulative impact assessment is done.

The consultants have also not looked at the need for free flowing stretches of rivers between the projects.

Section on Environmental Flows (Chapter 4 and 9): The section on Environmental flows is one of the weakest and most problematic sections of the report, despite the fact that the Executive summary talks about it as being one of the most crucial aspects.

The study does not use any globally accepted methodology for calculating eflows, but uses HEC RAS model, without any justification. The study has not been able to do even a literature review of methodologies of eflows used in India and concludes that “No information/criteria are available for India regarding requirement of minimum flow from various angles such as ecology, environment, human needs such as washing and bathing, fisheries etc.”

This is unacceptable as EAC itself has been recommending Building Block Methodology for calculating eflows which has been used (very faultily, but nonetheless) by basin studies even like Lohit, on which this study is supposedly based. EAC has also been following certain norms about E flow stipulations. CWC itself has said that minimum 20% flow is required in all seasons in all rivers. BK Chaturvedi committee has recently stipulated 50% e-flows in lean season and 30% in monsoon on daily changing basis.

The assumption of the study in its chapter on Environmental Flows that ‘most critical reach is till the time first tributary meets the river” is completely wrong. The study should concentrate at releasing optimum eflows from the barrage, without considering tributary contribution as an excuse.

First step of any robust eflows exercise is to set objectives. But the study does not even refer to this and generates huge tables for water depths, flow velocity, etc., for releases ranging from 10% lean season flow to 100% lean season flow.

After this extensive analysis without any objective setting, the study, without any justification (the justification for snow trout used is extremely flawed. Trouts migrate twice in a year and when they migrate in post monsoon months, the depth and velocity needed is much higher than the recommended 10% lean season flow) recommends “In view of the above-said modeling results, water release in lean season for fishes maybe kept between 10-15% for migration and sustaining ecological functions except Hiya and Nyepin HEP. Therefore, it is suggested that the minimum 20-25% water flow in lean season may be maintained at all HEP for fish migration and ecological balance.”

The study does not recommend any monsoon flows. Neither does it study impact of hydro peaking on downstream ecosystems.

Shockingly, the study does not even stick with this 20-25% lean season flow recommendation (20-25% of what? Average lean season flow? Three consecutive leanest months? The study does not explain this). In fact in Chapter 9 on Environmental Flows, the final recommendation is: “Therefore, it is suggested that the minimum 20-25% water flow in lean season may be maintained at Hiya and Nyepin  HEP or all other locations for fish migration.” (emphasis added)

So it is unclear if the study recommends 20-25% lean season flows or 10-15% lean season flows. This is a very flawed approach to a critical topic like eflows.

The study keeps mentioning ‘minimum flows’ nomenclature, which shows the flawed understanding of the consultants about e-flows.

The entire eflows section has to be reworked, objectives have to be set, methodology like Building Block Methodology has to be used with wide participation, including from Assam. Such exercises have been performed in the past and members of the current EAC like Dr. K.D. Joshi from CIFRI have been a part of this. In this case, EAC cannot accept flawed eflows studies like this. (DR. K D. Joshi has been a part of a study done by WWF to arrive at eflows through BBM methodology for Ganga in Allahabad during Kumbh: Environmental Flows for Kumbh 2013 at Triveni Sangam, Allahabad and has been a co author of this report)

Chocolate Mahseer in Subansiri  Source:
Chocolate Mahseer in Subansiri

Mockery of rich Subansiri Fisheries Subansiri has some of the richest riverine fisheries in India. The river has over 171 fish species, including some species new to science, and forms an important component of livelihood and nutritional security in the downstream stretches in Assam.

But the study makes a mockery of this saying that the livelihoods dependence on fisheries is negligible. The entire Chapter on Fisheries needs to be reworked to include impacts on fisheries in the downstream upto Majuli Islands in Assam at least.

No mention of National Aquatic Animal! Subansiri is one of the only tributaries of Brahmaputra with a resident population of the endangered Gangetic Dolphin, which is also the National aquatic animal of India (Baruah et al, 2012, Grave Danger for the Ganges Dolphin (Platanista ganegtica) in the Subansiri River due to large Hydroelectric Project

Shockingly, the Basin Study does not even mention Gangetic Dolphin once in the entire study, let alone making recommendations to protect this specie!

Gangetic Dolphin is important not only from the ecological perspective, but also socio cultural perspective. Many fisher folk in Assam co-fish with the Gangetic River Dolphin. These intricate socio ecological links do not find any mention in the Basin study, which is unacceptable.

Agitation Against Lower Subansiri Dam in Assam Source: SANDRP
Agitation Against Lower Subansiri Dam in Assam
Source: SANDRP

Lessons from Lower Subansiri Project not learnt A massive agitation is ongoing in Assam against the under construction 2000 MW Subansiri Lower HEP. The people had to resort to this agitation since the Lower Subansiri HEP was going ahead without studying or resolving basic downstream, flood and safety issues. The work on the project has been stopped since December 2011, for 22 months now. In the meantime several committee have been set up, several changes in the project has been accepted. However, looking at this shoddy CIA, it seems no lessons have been learnt from this ongoing episode. This study does not even acknowledge the reality of this agitation and the issues that the agitation has thrown up. There is no reflection of the issues here in this study that is agitating the people who are stood up against the Lower Subansiri HEP. The same people will also face adverse impacts of the large number of additional projects planned in the Subansiri basin. If the issues raised by these agitating people are not resolved in credible way, the events now unfolding in Assam will continue to plague the other planned projects too.

Conclusion From the above it is clear that this is far from satisfactory report. The report has not done proper cumulative assessment on most aspects. It has not even used information available in public domain on a number of projects. It does not seem to the aware of the history of the environmental mis-governance in the SubansiriBasin as narrated in brief in Annexure 1. For most projects basic information is lacking. Considering the track record of Central Water Commission functioning as lobby FOR big dams, such a study should have never been given to CWC. One of the reasons the study was assigned by the EAC to the Central Water Commission was that the CWC is supposed to have expertise in hydrological issues, and also can take care of the interstate issues. However, the study has NOT been done by CWC, but by consultants hired by CWC, so CWC seems to have no role in this except hiring consultant. So the basic purpose of giving the study to CWC by EAC has not been served. Secondly the choice of consultants done by the CWC seems to be improper. Hence we have a shoddy piece of work. This study cannot be useful as CIA and it may be better for EAC to ask MoEF for a more appropriate body to do such a study. In any case, the current study is not of acceptable quality.

South Asia Network on Dams, Rivers & People (


Set Conditions to be waived Later – The MoEF way of Environmental Governance

In 2002, the 2,000 MW Lower Subansiri hydroelectric project on the Assam-Arunachal Pradesh border came for approval to the Standing Committee of the Indian Board for Wildlife (now called the National Board for Wildlife) as a part of the Tale Valley Sanctuary in AP was getting submerged in the project. The total area to be impacted was 3,739.9 ha which also included notified reserved forests in Arunachal Pradesh and Assam.  The Standing Committee observed that important wildlife habitats and species well beyond the Tale Valley Sanctuary, both in the upstream and downstream areas, would be affected (e.g. a crucial elephant corridor, Gangetic river dolphins) and that the Environmental Impact Assessment studies were of a very poor quality. However, despite serious objections raised by non-official members including Bittu Sahgal, Editor, Sanctuary, Valmik Thapar, M.K. Ranjitsinh and the BNHS, the Ministry of Environment & Forests (MoEF) bulldozed the clearance through in a May 2003 meeting of the IBWL Standing Committee. Thus a project, which did not deserve to receive clearance, was pushed through with certain stringent conditions imposed (Neeraj Vagholikar, Sanctuary Asia, April 2009).

Lower Subansiri HEP Source: The Hindu
Lower Subansiri Dam
Source: The Hindu

The EC given to the project was challenged in Supreme Court (SC) by Dr L.M Nath, a former member of the Indian Board for Wildlife. Nath pleaded, these pristine rich and dense forests classified as tropical moist evergreen forest, are among the finest in the country. Further the surveys conducted by the Botanical Survey of India and the Zoological Survey of India were found to be extremely poor quality. The Application mentions that the Additional DG of Forests (Wildlife) was of the view that the survey reports of the BSI and ZSI reports were not acceptable to him because these organisations had merely spent five days in the field and produced a report of no significance.

The SC gave its final verdict on 19-4-2004, in which the Court upheld the EC given by MoEF to NHPC but with direction to fulfill some important conditions. Out these conditions there were two conditions which were very significant – “The Reserve Forest area that forms part of the catchment of the Lower Subansri including the reservoir should be declared as a National Park/ Sanctuary. NHPC will provide funds for the survey and demarcation of the same.”, and “There would be no construction of dam upstream of the Subansri River in future.” These conditions were also mentioned in the original EC given to the project in 2003.

In May 2005, two years after the EC was given the Arunachal Pradesh govt and NHPC approached the SC to waive or modify the above two conditions. The state government calimed that following these conditions would imply loss of opportunity to develop 16 mega dams in the upstream of Lower Subansiri (this including 1,600 MW Middle Subansiri and 2,000 MW Upper Subansiri to be developed by NHPC). The SC sent it back to National Board for Wildlife to review the conditions.

The petition was done strategically. “The strategy of the dam proponents is simple. They raised no objection to the terms until the construction of the Lower Subansiri project had proceeded beyond a point when it could have been cancelled. Armed with this fait accompli, they asked for a review of the clauses on the very basis on which the original clearance – laid down by members who were subsequently dropped from the wildlife board – was granted.”[ii]

Then nonofficial members of NBWL expressed their dissent to the proposal. In a May 2008 communication to the Chairman of the NBWL Standing Committee, member Dr. Bibhab Talukdar observed: “If the Standing Committee agrees to waive the conditions, we would be setting a dangerous precedent and sending a wrong signal regarding the credibility of decision-making by us. This would mean that projects impacting rich wildlife habitats can receive clearances based on stringent conditions, only to be up for review later. Such an approach is undesirable both from a perspective of good governance as well as the long-term interest of wildlife in the country.”

Dr. Asad Rahmani of the BNHS, who was part of a sub-committee of the NBWL Standing Committee conducting a site visit to the project area, stated in his report: “Under no circumstances should new projects be allowed in the Subansiri river basin until an advance cumulative assessment of proposed projects and a carrying capacity study of the Subansiri river basin are completed.”

In the December 12 2008 meeting of NBWL Standing Committee, even after these dissenting opinions from nonofficial members MoEF managed to do a dilution of the above two conditions. Assam that time was witnessing a major protest concerning the downstream impacts of Lower Subansiri HEP but it was not even consulted. Shockingly the “no dam upstream” condition was removed and it was decided that “any proposal in the upstream of the SubansiriRiver would be considered independently on its merit by the Standing Committee as and when submitted by the proponents”.

Now the Arunachal Pradesh government needs to declare a smaller area of 168 sq. km. as a sanctuary and “make serious efforts” to bring an additional 332 sq. km. reserved forest under the category of Conservation Reserve (CR) in consultation with the MoEF. The latter part of the condition (declaration of CR) is non-enforceable because of the choice of words. Even the demand to at least conduct an advanced cumulative impact assessment of proposed projects and a carrying capacity study of the Subansiri river basin has been ignored[iii].

As Bittu Sahgal, Editor, Sanctuary Asia says, “The Lower Subansiri is one such, where the PMO has placed a very dubious role in forcing clearances, agreeing to clearance conditions and then starting the project, only to loosen the environmental conditions. In this whole scam the Zoological Survey of India and the Botanical Survey of India have been co-conspirators that have suppressed the ecological value of the forests to facilitate the building of the dam, which will drown pristine elephant, tiger and clouded leopard forests and cause havoc downstream as well.”

The above sequence of events are very pertinent to remember as we see the Subansiri basin study.


[i] Website says: “More than 200 successful environmental Impact Assessment Clearance from Ministry of Environment & Forests, Government of India for Industry, Infrastructure & Construction projects” Sounds strange from an EIA consultant.

[iii] For more details please see – “Forest Case Update”, Issue 1, June 2004 and “The Subansiri Subversion” by Neeraj Vagholikar published in Sanctuary Asia, April 2009 issue