PANCHESHWAR MULTIPURPOSE PROJECT DETAILED PROJECT …€¦ · PANCHESHWAR MULTIPURPOSE PROJECT...

PANCHESHWAR DEVELOPMENT AUTHORITY (PDA)

(Bi-national Entity of India and Nepal)

Consultant:

[email protected],

Website: http://www.wapcos.gov.in

VOLUME I

SECTION 1: EXECUTIVE SUMMARY

PANCHESHWAR MULTIPURPOSE PROJECT

DETAILED PROJECT REPORT

GOVERNMENT OF INDIA Ministry of Water Resources,

River Development and Ganga Rejuvenation

GOVERNMENT OF NEPAL Ministry of Energy


DETAILED PROJECT REPORT

VOLUME - I


PANCHESHWAR DEVELOPMENT AUTHORITY

(Bi-national Entity of India and Nepal)

PANCHESHWAR MULTIPURPOSE PROJECT DETAILED PROJECT REPORT

Section 1: Executive Summary Page i

Section 1:

Executive Summary





Table of Contents

Sub-Section Sub-Headings PageNos.

1.1 Introduction 11.1.1 Background 11.1.2 Project Location 21.1.3 Mahakali River Basin 31.1.4 Climate 41.1.5 Water Resources 41.1.6 Access 41.1.7 Project Features 41.1.8 Hydropower Potential in the Mahakali Basin 51.1.9 Population and Economy of the Project Area 5

1.1.10 Resettlement and Relocation Plans 51.1.11 Physical Environment 5

1.2 Previous Studies 61.2.1 WAPCOS Initial Studies -1971 61.2.2 Nepal DPR -1995 61.2.3 Joint Investigations by JPO-PI (2000-02) 61.2.4 Indian draft DPR -2003 6

1.3 Field Investigations and Studies of PancheshwarMultipurpose Project

7

1.3.1 Topography 71.3.2 Hydrology & Meteorology 81.3.3 Geology/ Geotechnics 11

1.3.3.1 Regional Geology 111.3.3.2 Geotechnical Investigations 121.3.3.3 Geology of Pancheshwar Reservoir 131.3.3.4 Geology of Pancheshwar Dam site 141.3.3.5 Geology of Pancheshwar Spillway and Plunge pool 151.3.3.6 Geology of UGPH on Left Bank (Nepal Side) 161.3.3.7 Geology of UGPH on Right Bank (India Side) 171.3.3.8 Geology of Diversion Works –Tunnels and Coffer dams 181.3.3.9 Geology of Rupaligad Dam Site and Spillway 18

1.3.3.10 Geology of UGPH on the Left Bank (Nepal Side) 201.3.3.11 Geology of UGPH on the Right Bank (India side) 201.3.3.12 Geology of Diversion works- Tunnels and Coffer Dam 21


Section 1: Executive Summary Page ii

1.4 Sedimentation Studies 221.4.1 Pancheshwar Reservoir 221.4.2 Rupaligad Re-regulation Reservoir 23

1.5 Construction Materials 231.5.1 Materials Survey 231.5.2 Material Requirements - Pancheshwar 241.5.3 Laboratory Tests - Pancheshwar 241.5.4 Material Requirements - Rupaligad 25

1.6 Seismicity 261.7 Infrastructure and Communication Survey 261.8 Benefit Assessment & Project Optimization of

Pancheshwar Multipurpose Project27

1.8.1 Power Market Review 271.8.2 Power and Energy Benefits 271.8.3 Irrigation Benefits 281.8.4 Flood Control Benefits 31

1.9 Design of Civil Structures & Preliminary Layout ofPancheshwar Multipurpose Project

31

1.9.1 Pancheshwar Rockfill Dam 311.9.1.1 Concrete Dam Axis 311.9.1.2 Rockfill Dam Axis 32

1.9.2 Reasons for Selection of Rockfill Dam 331.9.2.1 Geological Consideration 331.9.2.2 Seismic Consideration 341.9.2.3 Materials Consideration 34

1.9.3 Pancheshwar - General Layout and Project Components 341.9.3.1 General Layout 341.9.3.2 Diversion and Outlet Facilities 341.9.3.3 Diversion Tunnels 351.9.3.4 Cofferdams 351.9.3.5 Depletion Arrangements 351.9.3.6 Design of Rockfill Dam 361.9.3.7 Foundation Treatment of Pancheshwar Dam 361.9.3.8 Design of Pancheshwar Spillway 361.9.3.9 Intake and Pressure Tunnels 37

1.9.3.10 Vertical Drop Shafts/ Penstocks 371.9.3.11 Pancheshwar Dam - Power Houses 371.9.3.12 Pancheshwar Dam - Downstream Surge Galleries 371.9.3.13 Draft Tube Tunnels/ Tail Race Tunnels at Pancheshwar 381.9.4 Rupaligad Re-Regulating Dam 38

1.9.4.1 General Layout 381.9.4.2 Rupaligad Concrete Gravity Dam 381.9.4.3 Rupaligad Dam - Spillway and Energy Dissipation

Arrangement39

1.9.4.4 Rupaligad Dam - Diversion Arrangements 401.9.4.5 Rupaligad Dam – Power Intakes and Headrace Tunnels 401.9.4.6 Rupaligad Dam - Power Powerhouse caverns 41


Section 1: Executive Summary Page iii

1.9.4.7 Rupaligad Dam – Tailrace Tunnels 411.10 Design of Electrical and Mechanical Works 41

1.10.1 Pancheshwar Power Stations 411.10.2 Rupaligad Power Stations 42

1.11 Transmission System for Pancheshwar MultipurposeProject

42

1.11.1 Evacuation System for Pancheswar Power Plants 421.11.2 Evacuation System for Rupaligad Power Plants 43

1.12 Environmental and Socio-Economic ImpactAssessment

44

1.12.1 Flora & Fauna 441.12.2 Rehabilitation & Resettlement 441.12.3 Environmental Management Plan including R & R Plan 45

1.13 Construction Schedule and Equipment Planning 451.13.1 Basic Considerations 451.13.2 Access Roads and Infrastructure Facilities 451.13.3 Equipment Planning 461.13.4 Construction Programme 46

1.14 Cost Estimates & Phasing of Expenditure 461.14.1 Abstract of Cost Estimates 461.14.2 Phasing of Expenditure 49

1.15 Economic and Financial Evaluation 491.15.1 Cost chargeable to Irrigation and Flood Control

Component50

1.15.2 Cost chargeable to Power Component 501.15.3 Capitalized Cost of Hydropower Project 521.15.4 Levelized Tariff and Internal Rate of Return (IRR) 52

1.16 International and Interstate Aspects 521.16.1 Irrigation Benefits 531.16.2 Power Benefits 541.16.3 Inter-state Agreements 541.16.4 Interstate Aspects of the Project 551.16.5 International Aspects of the Project 551.16.6 Dispute Resolution Mechanism 561.16.7 Power Purchase Agreements 56

1.17 Project Management and Design EngineeringConsultancy

56

1.18 Conclusions and Recommendations 57

List of AnnexureAnnex-IAnnex-II

Salient Features of Pancheshwar Dam 59Salient Features of Rupaligad Re-regulating Dam 65


Section 1: Executive Summary Page iv

List of Tables

Table No. Description Page No.Table 1.3-1 Average Monthly Temperature at Pancheshwar dam

site8

Table 1.3-2 Average Monthly Rainfall at Pancheshwar dam site 9Table 1.3-3 Average Monthly Lake Evaporation at Pancheshwar

dam site9

Table 1.3-4 Average Monthly Inflows at Pancheshwar dam site 9Table 1.3-5 Floods for different Return period (m3/s) 10Table 1.3-6 Rock Sequence from South (Tanakpur) to North

(Tawaghat)10

Table 1.3-7 Changes in Reservoir Capacity with sedimentation 11Table 1.5-1 Construction Materials Balance – Pancheshwar 24Table 1.8-1 Annual Energy Generation 28Table 1.8-2 Total Water Requirement of India and Nepal

including River Eco-System (in m3/s)68

Table 1.14-1 Abstract of cost of Pancheshwar Dam 47Table-1.14-2 Abstract of Cost of Rupaligad Dam 48Table 1.14-3 Yearly requirement of funds to both countries (in

INR Million)49

Table 1.15-1 Assessment of Project Benefits 50Table 1.15-2 Apportionment of project cost in power and irrigation

sector51

Table 1.15-3 Phasing of Expenditure on power component ofPMP (in INR million)

52

Table 1.15-4 Levelized Tariff and IRR for different loan repaymentperiods

52

Table 1.16-1 Various parameters of Project 54


Section 1: Executive Summary Page v

List of Drawings

Sr. No. Drawing No. Title of DrawingsA. General

1. DRG.NO.WAP/PANCH/ES-01 Index Map of Pancheshwar Multipurpose Project2. DRG.NO.WAP/PANCH/ES-02 Regional Geological Map of Project Area

B. Pancheshwar Dam

3. DRG.NO.WAP/PANCH/ES-03 Geological Map of Pancheshwar Dam Site4. DRG.NO.WAP/PANCH/ES-04 Layout Plan Showing Drill Holes & Drifts5. DRG.NO.WAP/PANCH/ES-05 Geological Section along Rockfill Dam6. DRG.NO.WAP/PANCH/ES-06 General Layout Plan of Pancheshwar Dam7. DRG.NO.WAP/PANCH/ES-07 L-Section along Pressure Tunnel8. DRG.NO.WAP/PANCH/ES-08 Maximum Section of Rockfill Dam9. DRG.NO.WAP/PANCH/ES-09 Pancheshwar Spillway –

Maximum Over Flow Section10. DRG.NO.WAP/PANCH/ES-10 Pancheshwar Spillway-

Maximum Non-Over Flow Section11. DRG.NO.WAP/PANCH/ES-11 Power House Cross-Section12. DRG.NO.WAP/PANCH/ES-12 Layout Of Machine Hall, Bus Duct Galleries &

Transformer Hall13. DRG.NO.WAP/PANCH/ES-13 Schematic Diagram of 11kv & 415v Ac

Switchgears14. DRG.NO.WAP/PANCH/ES-14 Location Plan of Quarry, Borrow Area and Muck

Disposal AreasC. Rupaligad Re-regulating Dam

15. DRG.NO.WAP/PANCH/ES-15 Geological Map with Location of Drill Holes andDrifts at Rupaligad

16. DRG.NO.WAP/PANCH/ES-16 Geological Section along the Rupaligad dam17. DRG.NO.WAP/PANCH/ES-17 Rupaligad Dam – General Layout Plan18. DRG.NO.WAP/PANCH/ES-18 L-Section Through Water Conductor System19. DRG.NO.WAP/PANCH/ES-19 Rupaligad Dam - Upstream Elevation20. DRG.NO.WAP/PANCH/ES-20 Maximum Non-Over Flow Section of Dam21. DRG.NO.WAP/PANCH/ES-21 Rupaligad Power House Cross-Section22. DRG.NO.WAP/PANCH/ES-22 Layout Plan of M/C Hall, Bus Duct Galleries &

Transformer Hall23. DRG.NO.WAP/PANCH/ES-23 Schematic Diagram of 11kv & 415 V L.T.A.C.

Switchgears24. DRG.NO.WAP/PANCH/ES-24 Location Map of Quarry area, Roads and

Infrastructure Facilities at Rupaligad dam


Section 1: Executive Summary Page vi


Section 1: Executive Summary Page 1


1.1 Introduction

1.1.1 Background

A Treaty between His Majesty's Government of Nepal and Government of Indiaconcerning the Integrated Development of the Mahakali River including SaradaBarrage, Tanakpur Barrage and Pancheshwar Project was signed on February 12,1996 by the Prime Ministers of India and Nepal. As per Article-3 of the Treaty, boththe governments agreed to implement the Pancheshwar Project on the MahakaliRiver where it forms the international boundary between the Far WesternDevelopment Region of Nepal and the Uttrakhand State in India. In accordance withthe principles enunciated therein, the Project shall be designed to produce themaximum total net benefits, accruing to both the parties, in the form of powergeneration, irrigation, flood control, etc.

The Pancheshwar dam project is a bi-national project, primarily aimed at energyproduction. In addition, it would enhance the food grains production in both thecountries by providing additional irrigation resulting from the augmentation of dryseason flows. Due to moderation of flood peaks at reservoir(s), incidental floodcontrol benefits are also envisaged from the project.

Actual photograph of Pancheshwar dam site



Pursuant to the Article-10 of the Treaty, the Government of India (GOI) and theGovernment of Nepal (GON) agreed to set up the Pancheshwar DevelopmentAuthority, an independent autonomous body, to finalize the Detailed Project Reportand expedite the implementation of the Pancheshwar Project. The Authority isheaded by the Water Resources/ Energy Secretaries from the GOI and GON. It wasagreed that the Pancheshwar Development Authority (PDA) shall take immediatemeasures to finalize the Detailed Project Report (DPR) of PancheshwarMultipurpose Project.

In order to expedite the finalization of the Pancheshwar DPR, the water resources/energy secretaries of India and Nepal decided to award the work of updation of DPRincluding the additional field investigations, if necessary, to M/s WAPCOS Limited, inthe second meeting of the Governing Body of PDA held in November 2014 at NewDelhi.

The updated DPR is aimed to summarize the results of all previous studies and fieldinvestigations carried out by both sides independently and/or jointly including theadditional field investigations and studies carried out by WAPCOS Limited; todevelop a mutually acceptable technical solution, estimate with sufficient accuracythe project costs and benefits, and carry out the analyses required to confirmeconomic and financial feasibility of the Project in accordance with the principlesenshrined in the Mahakali Treaty -1996.

1.1.2 Project Location

The Pancheshwar dam site is located near the Pancheshwar temple which is about2.5 km downstream of the confluence of River Mahakali with the Sarju River. A re-regulating dam is also proposed downstream of the main dam to even out peakingflows released from Pancheshwar power houses for meeting downstream irrigationwater requirement. For this purpose, two alternative locations were identified; one atRupaligad, 27 km downstream of the main dam and another at Purnagiri, 61 kmdownstream of main dam. Finally, the Rupaligad site was agreed by the two sides forlocating the re-regulating dam in the 3rd meeting of Joint Committee of WaterResources (JCWR) held in November 2009 at Pokhara (Nepal). An Index Mapshowing location of main dam, re-regulating dam and the exiting irrigation structuresis at Figure 1.1-1.

The project structures, including the reservoir area, lie in the Champawat,Pithoragarh, Bageshwar and Almora districts of Uttarakhand state in India and in theBaitadi and Dharchula districts of Nepal.



Figure 1.1-1: Index Map of the Project

1.1.3 The Mahakali River Basin

The Mahakali (Sarada) basin up to the Pancheshwar dam site has a total catchmentarea of 12,276 km2; out of which an area of 9,861 km2 lies in India, and remaining2415 km2 in Nepal.

During its course, the Mahakali river carries the flows from a number of majortributaries, viz. the Dhauli Ganga (catchment 1357 km2), the Gauri Ganga(catchment 2300 km2) and the Sarju (catchment 4019 km2) from the Indian side andthe river Chamaliya (catchment 1572 km2) from t he Nepal side. The other minortributaries joining the Mahakali River, below the Pancheshwar site are the Lohawatiand the Ladhiya rivers from Indian side and the Surnayagad, the Rupaligad, theSirsegad and the Ragunkhola from the Nepal side before the Mahakali Riveremerges onto the Gangetic plains near the Purnagiri temple before the Tanakpurtown.



1.1.4 Climate

The south - west Monsoon sets in the project area in the last week of May or in earlyJune and continues up to the mid October. The total annual rainfall in the basinranges from 1000 mm to 2000 mm, out of which 70-75% of the total precipitationoccurs during the monsoon months of June to September. The maximumprecipitation generally occurs in the months of July and August.

1.1.5 Water Resources

The long term average discharge at the Pancheshwar dam site is estimated to be582m3/s. A n additional runoff from the intervening catchment between thePancheshwar to Rupaligad site is estimated to be 39 m3/s.

1.1.6 Access

At present, the only access to the project area by road is through Tanakpur -Lohaghat -Pancheshwar (about 130 km), from the Indian side. Access to the damsite from the Nepal side is possible only by helicopter or by 40km road from thePatan village and then 20 km trekking.

The existing roads on both sides will need major improvement and relocating for theconstruction of the project as the last portion of the Indian road, approaching theactual dam site would be submerged in the reservoir. A new road along the left bankof the Mahakali River on the Nepal side has been proposed from the Brahmadeovillage to the Pancheshwar dam site for transport of heavy equipment andgenerating units. This road would be connected to the Tanakpur town in India byconstructing a new bridge over the Mahakali River.

1.1.7 Project Features

The Pancheshwar project comprises of a 311m high rock fill dam at Pancheshwarwith two underground power houses, one on each bank, having a total installedcapacity of 4800 MW (six units of 400MW each on either side). In addition, a 95mhigh concrete gravity dam has been envisaged at Rupaligad with two undergroundpower stations, one on each bank of the river having a total installed capacity of 240MW (two units of 60 MW each on each side). Besides the dams, the project shallhave all the appurtenant works, like, spillway, intake structures, water conductorsystem, surge shafts, pothead yards, etc.

The project will generate 7678 GWh energy annually at the main dam powerstations and 1438 GWh at the Rupaligad re-regulating dam power stations during90% dependable year.

In addition, the storage project will enhance the natural river flows during the non-monsoon months, and provide the year round irrigation to agricultural land in theKanchanpur District in Nepal. There would be intensification of irrigation system on



the Indian side during the Rabi season. Besides the above, the project will also haveincidental flood benefits on both sides.

1.1.8 Hydropower Development in the Mahakali Basin

No other storage scheme has been envisaged on the main stem of the MahakaliRiver upstream of the proposed Pancheshwar dam. On the Indian side, a storageproject near Chamgad was envisaged on the River Sarju, as an alternative to thePancheshwar Project which has been shelved as it would be submerged in thePancheshwar reservoir.

The National Hydroelectric Power Corporation (NHPC), India has commissioned a280 MW Dhauliganga HE Project in the upstream of Pancheshwar reservoir on theDhauliganga River. Some more schemes are also planned on the river Gaurigangain the upstream of Pancheshwar reservoir.

Similarly, the Nepal side has planned a 30 MW HE Project, a medium size projecton the Chameliya river. In addition, Nepal has also carried out a master plan studyof the Mahakali River in their territory.

1.1.9 Population and Economy

The population density in the project area on both sides, India (259 persons/ km2)and Nepal (69 persons/ km2 as per EIA Report of Nepal side) is low as compared toaverage densities in both the countries. Subsistence agriculture is at present theprimary economic activity in the project area, both in India and in Nepal.

1.1.10 Resettlement and Relocation

The Pancheshwar reservoir will displace a total of 29436 project affected families(PAF) due to Pancheshwar dam on the Indian side and 2786 households (as per2006 data) in the Baitadi District on Nepal side of the river. In Nepal, it is proposed touse part of the agricultural area to be irrigated by the project to relocate thesepersons in Kanchanpur. The persons affected on the Indian side would be resettledat appropriate locations in consultation with the local population by the stateadministration as per the resettlement policies in India.

The Rupaligad dam would also submerge a total area of 396 ha of which 182 ha liesin India and rest in Nepal. About 1587 families in eleven villages of the districtChampawat would be affected in India. The PAFs in Nepal side are being collectedfrom Nepal.

1.1.11 Physical Environment

The main reservoir of Pancheshwar would submerge 116 km2 area of which 76 km2

would be in India and balance in Nepal. About 21.95 km2 of agriculture land inIndia and 13.78 km2 in Nepal would be coming under submergence of Pancheshwarreservoir.



The project area is mostly covered with Sal forests, which could be classified asmoderately thick. One endangered tree species, Alstonia Scholaris, is located in theproject area.

The intervening catchment area up to the Rupaligad dam consists of Shiwalik Salforest and Himalyan Chir forests, with young to full grown trees. The area hasvariety of trees having commercial value such as Sal, Sheesam, Chir, Sain, Bakli,Haldu, Bahedi, Jhingan, Toon, Khair, Gutel, Rohini, Kaula etc.

1.2 Previous Studies

1.2.1 WAPCOS Initial Studies -1971

Investigations and basic studies for the Pancheshwar Project were initially carriedout by the State of Uttar Pradesh during the 1960s. These investigations mainlycovered the Topographical Surveys, Geological Investigations, ConstructionMaterial Investigations and Hydro-meteorological Observations. Based on theabove field investigations, a feasibility report on the Pancheshwar project wasprepared by WAPCOS India Limited in November 1971. It suggested a 247m highconcrete gravity dam at Pancheshwar with a dam toe powerhouse having four unitsof 250 MW each.

1.2.2 Nepal DPR -1995

Based on the independent studies carried out by the Indian side from 1981 to 1991and some joint studies carried out during the years 1991 to 1994, the Nepal sideprepared a draft DPR of Pancheshwar Multipurpose Project in 1995 and forwarded itto the Indian side for consideration. On examination the DPR, it was realized thatadditional field investigations and studies were required to finalize a mutuallyacceptable report.

1.2.3 Joint Investigation by JPO-PI

Realizing the need for additional investigations and studies to be carried outjointly, for the main dam as well as for the re-regulating dam at an optimal location,it was decided to set up a Joint Project Office (JPO-PI) at Kathmandu with fieldoffices at the project sites in 1999. The required investigations and studies werecarried out by JPO-PI between 2000-2002 for locating the downstream re-regulating dam either at Rupaligad or at Purnagiri site.

1.2.4 Indian Draft DPR -2003

After completion of additional surveys and investigations at Pancheshwar dam,Rupaligad and Purnagiri dam sites, JPO –PI tried to finalize a mutually agreeableDPR in 2002. However, it could not be completed due to difference in opinion oncertain issues, mainly, units’ size and installed capacity of Pancheshwar powerplants, non-finalization of location of downstream re-regulating dam, assessment of



irrigation benefits to India, apportionment of the project cost to each side, etc. TheJPO-PI was closed in July 2002 and the relevant data/ records were shifted toCentral Water Commission, New Delhi.

In order to ensure that the newly collected data, during the joint fieldinvestigations carried out by the JPO-PI, does not remain unutilized, a draft reportwas prepared by the Indian side which could form a basis for finalization of the jointdetailed project report, later on. The Indian draft DPR -2003 envisaged a 184 m highrock fill dam at Purnagiri site, as a re-regulating dam, to intercept the interveningbasin area of around 3000 sq km and make optimal use of hydro power potential ofthe Mahakali River. The Indian draft report of 2003 had retained many projectparameters related to main dam at Pancheshwar as suggested in the Nepal DPR-1995.

1.3 Field Investigations and Studies

1.3.1 Topography

Based on the understanding reached at a meeting of representatives of theNepalese and Indian Survey Departments held in Kathmandu on September 4-6,1991, topographic maps of the dam site were prepared jointly covering both banks ofthe river up to EI 940 m, with 2m contour interval. In addition, maps were alsoprepared jointly by the Survey of India (Government of India) and Department ofSurveys (Government of Nepal) for reservoir area and re-regulating dam sites.



In addition to the above, detailed topographic surveys have been carried out recentlyby WAPCOS Limited for the areas to locate Owners' and Contractors' camps,temporary construction facilities, borrow areas and other infrastructures facilities,including the proposed new road along the Nepal bank.

1.3.2 Hydrology & Meteorology

1.3.2.1 Field data

A meteorological station was set up at Pancheshwar dam site in 1982 in the Indianside. A similar station was established at the Pancheshwar Field Camp on theNepal side in 1989. The JPO-PI also set up weather stations at Pancheshwar,Rupaligad and Purnagiri sites in 1999 recording daily/ hourly rainfall, dry /wet bulbtemperatures, maximum and minimum temperatures, wind speed & direction andsunshine.

In addition, gauge discharge and silt observations were also started at Pancheshwardam site by India from 1983 and later on, joint observations were carried out fromNepal bank of the river during 1991-93.

The aforesaid data was obtained by WAPCOS Limited from the concerned agenciesand utilized in the assessment of long term average annual discharge at the projectsites, flood and sediment load estimation.

Additional rainfall data available with India Meteorological Department and theGovernment of Nepal was also collected and utilized in the updated hydrologicalstudies.

1.3.2.2 Mean Monthly Temperature

The climate and precipitation pattern over the project area is governed by themonsoon. The mean monthly temperature at the Pancheshwar dam site variesbetween 140 C to 300 C, as shown in the Table-1.3-1.

Table 1.3-1: Average Monthly Temperature at Pancheshwar dam site

Month T0C Month T0C Month T0CJanuary 14.2 May 28.8 September 28.7February 16.4 June 30.4 October 24.5March 21.1 July 29.1 November 19.5April 26.4 August 29.2 December 14.9

1.3.2.3 Monthly Rainfall

Total annual rainfall in the basin ranges from 1000 mm to 2000 mm, with about75% of the total precipitation occurring during the monsoon months of June toSeptember. Maximum precipitation generally occurs in July and August. The



average monthly rainfall at Pancheshwar Dam site is given in The Table 1.3-2.

Table 1.3-2: Average Monthly Rainfall at Pancheshwar dam site

Month mm Month mm Month MmJanuary 29.3 May 98.2 September 146.7February 45.0 June 103.7 October 35.6March 33.2 July 220.6 November 5.4April 41.4 August 201.0 December 18.9

1.3.2.4 Mean Lake Evaporation

The lake evaporation data recorded at the measurement stations set up by bothsides was adopted and given in Table- 1.3-3.

Table 1.3-3: Average Monthly Lake Evaporation at Pancheshwar dam site

Month Mm Month mm Month MmJanuary 22.8 May 149.7 September 98.5February 38.8 June 133.8 October 85.5March 77.0 July 123.3 November 43.6April 135.4 August 108.3 December 26.2

1.3.2.5 Mean Monthly Inflows at Pancheshwar

The 50 years mean monthly flows starting from January 1962 to December 2012are developed for the Mahakali River at the Pancheshwar Dam site on the basis ofearlier gauge heights recorded by India, Nepalese gauge heights along with flowmeasurements. A correlation was established with the measured flows of theKarnali River as well. According to these studies, the average annual flows of theMahakali River at Pancheshwar dam site, Rupaligad and Purnagiri GDS sites areestimated to be 582 m3Is, 621 m3Is and 667 m3/s respectively, with the monthlydistribution as shown in the Table 1.3-4, Table 1.3-5 and Table 1.3-6.

Table 1.3-4: Average Monthly Inflows at Pancheshwar dam site

Month m3/s Month m3/s Month m3/sJanuary 164 May 334 September 1193February 150 June 602 October 507March 157 July 1383 November 268April 206 August 1805 December 194



Table 1.3-5: Average Monthly Inflows at Rupaligad dam site


Table 1.3-6: Average Monthly Inflows at Purnagiri GDS site


1.3.2.6 Runoff from Intermediate catchment

Based on the above flow data, the intermediate catchments’ contribution betweenthe Pancheshwar - Rupaligad was assessed to utilize it for the correspondingenergy production at Rupaligad. Further, the intermediate catchments’ contributionbetween the Rupaligad - Purnagiri sites was assessed to meet the waterrequirements for irrigation in the downstream at the Tanakpur barrage.

The annual average runoff from the intermediate catchments between Pancheshwarand Rupaligad and between Pancheshwar and Purnagiri sites are estimated as1230 Million m3 and 2695 Million m3 respectively.



The 75% dependable year runoff from the intermediate catchments betweenPancheshwar and Purnagiri/ Tanakpur barrage site has been assessed around2175 Million m3 only.

1.3.2.7 Flood Estimation at Pancheshwar dam site

The Probable Maximum Precipitation (PMP) in earlier studies was estimated onthe basis of the storm of September 28-30, 1924, which had occurred to the westof the Mahakali Basin in India. It was reviewed and found valid as on date. Based onthe above PMP, the PMF at the Pancheshwar and Rupaligad dam sites remainsunchanged and assessed to be 23,500m3/s and 27,700m3/s respectively. Floods ofsmaller return periods were also determined through statistical analysis.

The Table 1.3-7 gives a summary of the basic characteristics of different floodsconsidered in the design of civil works for Pancheshwar as well as Rupaligad dams.

Table 1.3-7: Floods for different Return period (m3/s)

Return Period (yrs) Pancheshwar Peak Flow Rupaligad Peak Flow10 8272 887825 9867 1059050 11078 11890

100 12310 13212500 15296 16417

1000 16651 17871

1.3.2.8 Flood Estimation at Re-regulating Dam

The corresponding flood peaks at Rupaligad were estimated on catchment areaproportionate basis (proportionate to 3/4th power of Area). The above floods would bereviewed with the available site-specific data before taking up the construction ofdiversion works.

1.3.3 Geology/ Geotechnics

1.3.3.1 Regional Geology

The physiographic setting of Nepal and Uttrakhand State of India is dominatedby the Great Himalayan Mountain Range which are the result of the collisionbetween the Eurasian and Indian Tectonic plates. As the Indian plate is sub-ducted under the Eurasian plate, the upper crust is sheared off into a series ofthrust sheets. With the continued movement of the plates these sheets arecrumpled and folded. The collision of the plates started 40 to 50 million yearsago and uplift has continued since that time in conjunction with igneousintrusion, and erosion, to produce the present day landform.



The collision between the plates has produced five distinct physiographicprovinces that extended the length of Nepal parallel to the Himalayas. All five ofthe physiographic provinces are represented in a 150 km wide region ofPancheshwar Multipurpose Project covering adjacent areas of India & Nepal.

The area around the project site from south to north is occupied by a gamut ofrock types comprising of sedimentary, meta-sedimentary and crystalline, whichare separated from each other by tectono-structural discontinuities. Ageneralised sequence of the rocks in the area is shown in Table-1.3-8 fromsouth (Tanakpur) to North (Tawaghat).

The Pancheshwar dam is to rest over the rocks belonging to AlmoraCrystallines (Kalikot formation in Nepal). This Proterozoic Group of rocks, alongwith Central and Askot Crystallines and Ramgarh Group, are characterized byregionally metamorphosed katazonal meta-sediments of green schist andamphibolites facies.

Pancheshwar Multipurpose Project is located within two important tectonicsurfaces, the Main Central Thrust (MCT) towards north at a distance of about80 km and the Main Boundary Thrust (MBT) towards south at about 25 km.

1.3.3.2 Geotechnical Investigations:

To carry out the geological studies for the project area, extensive geological andgeotechnical investigations had been carried out at Pancheshwar and Rupaligad re-regulating dam site(s) starting from early eighties. It included surface geologicalmapping, diamond core drilling, test adits, seismic refraction surveys, in-situ rockmechanics testing, micro-seismic instrumentation and laboratory testing.

The work of geotechnical investigations at Pancheshwar and Rupaligad dam siteswere resumed again in the year 2015-16 by WAPCOS. Additional samples werecollected at site and tested in the laboratory by CSMRS, New Delhi.



For updating the Pancheshwar DPR, following additional geotechnical explorationswere conducted by WAPCOS Limited:

Twelve new boreholes at rock fill dam axis at Pancheshwar, two holes atChamtada landslide area in the upstream of the Pancheshwar dam, two deepholes; one on each underground cavern area totalling of 1800m.

In-situ rock mechanics tests in the existing drifts to ascertain the rock masscharacteristics at Pancheshwar dam site.

Geological and geotechnical investigations at the alternate Rupaligad dam site(lower dam axis) by drilling around 20 boreholes at dam axis and appurtenantstructures, totalling 2000 m in length.

All the boreholes were logged by the resident geologists at site and rocksamples were tested in the laboratories at CSMRS, New Delhi. The results ofin-situ and laboratory tests are given in the relevant sections.

1.3.3.3 Geology of Pancheshwar Reservoir

The Pancheshwar Reservoir is oriented in a north northeast-south southwestdirection which is roughly perpendicular to the north-westerly regional structuraltrend of the geologic units. The principal structural features that can be identifiedwithin the reservoir are a series of Klippe or windows, which represent remnants of aNappe or recumbent fold, where older igneous and metamorphic rocks from theMCT zone have been juxtaposed over groups of younger meta-sedimentary rocks.The dam site is located on the Dadeldhura Klippe.



The rocks within the reservoir are relatively weak with the exception of the dolomiteand quartzite units. In addition, the dip of the rock is generally steep, especially nearthe dam, which is favourable to reservoir impermeability. There are no signs of Karstconditions that could contribute to reservoir leakage.

1.3.3.4 Geology of Pancheshwar Dam Site:

Considering abutment attributes and completeness of geological investigation,experts of CWC and WAPCOS recommended for investigation of the dam axis D-D’.The axis D-D’ has been considered for Rockfill dam and further explored duringpresent investigation. In the dam site area, the river flows southerly through a deeplyentrenched, 70m - 150m wide water channel with 4-10m deep water with steeplysloping abutments (1:1), local sub-vertical micro scarps, and nick points and abruptchanges in the slope gradient. The rocks are exposed at the toe of the abutmentsand at higher slope segments thickness of overburden varies up to a maximum of38.40m. In the core zone of the dam, Quartz -biotite gneiss (Qbg) & Quartz-feldspathic Mica schist (Qfms) are exposed at places; Quartz- feldspathic Mica schist(Qfms) & Quartz biotite gneiss (Qbg) outcrops in the U/S part of shell -zone whereasQuartz biotite gneiss (Qbg), Micaceous quartzite (Mqtz) & Augen Gneisses (Augn) inthe D/S part of the shell zone. These rocks strike N51°W-S51°E and generally dipsteeply (70° to 75°) in SW quadrant. However, because of intricate folding, local



variations in the attitude of the formations are noted. The axial core zone along damaxis D-D’ including either of abutments has been explored with the help of 10 drillholes. Considering the exploratory holes taken in the central river section and eitherof the abutments a geological section along dam axis D-D’ has been evolved toillustrate the sub-surface geological framework.

1.3.3.5 Geology of Pancheshwar Spillway and Plunge pool

It is proposed to construct a 122.5 long gated spillway with crest level at 658m. Thespillway (dam) axis is oriented in N42° W- S42°E. The ground elevation in thespillway dam domain varies from 710m to 800m. It is obligatory to keep thefoundation at El.650m. This would involve 175m (max.) deep excavation to housethe proposed spillway head works. It is anticipated that at the foundation level, hardand compact micaceous quartzite and quartz biotite gneiss would be met with. It isproposed to excavate slopes at 1(H): 4(V) and 1(H): 6 (V) in moderately fresh rockhowever for safe excavation.

The longitudinal geological section illustrates the sub-surface geology of spillchannel domain from straight reach of the approach channel to plunge pool. The spillchannel is aligned N45Eº-S45ºW. As stated earlier, the rock excavation of the orderof 175m depth is required to house the spillway dam at El. +625m. A 122.50m wideand 410.00m long chute emanating from the head works would run down at thegradient of 2.5(H):1 (V), upto flip bucket. This involves the rock excavation varyingfrom 175m to 145m deep. The lateral training walls are proposed with 4m base widthand 7m height. The plunge pool is located about 315 downstream of the concreteapron on the left bank of the Mahakali River. The Rollegad nallah crosses theapproach to the plunge pool about 205m D/S of the concrete apron, hence it shallhave diverted suitably to Mahakali River, before the crossing. As discussed earlier,the spillway slope in the domain could be classified into two parts viz. rocky slopesegment above the Rollegad north of Rollegad nallah crossing and fan terracedslope between Rollegad and Mahakali River in the south.

The spill channel –plunge pool area has been explored with the help of 5 drill holesIn the sections of Rollegad nallah the rock are sporadically exposed. However due toerratic weathering, locally the overburden has large thickness ranges upto 24.50m(SDH-5). The rocks are moderately weathered to a depth of 39m (max); at furtherdepth, fresh and compact rock mass is encountered. In the section south of Rollegadnallah trending across the fan terrace 35m thick overburden consisting offanglomerate deposits, has been encountered. The explorations reveal that thefoundation domain of the spill channel consists of litho-units Quartz feldspathic micaschist, (Qfms, GSI 40-50), quartz- biotite gneiss, (Qbg, GSI 55-65), Micaceousquartzite (Mqtz, GSI 55-65) and augen gneiss (Augn, GSI 60-75); further beyond theplunge pool domain quartz feldspathic mica schist (Qfms) are anticipated. Thefoundation of the training wall would rest on litho-units Mqtz, and Augn. The major



part of the spill channel consists of augen gneiss (Augn), whereas the plunge pooldomain consists of quartz mica schist (Qfms).

1.3.3.6 Geology of UGPH on left Bank (Nepal Side)

The UGPH (H x W x L) 57.3m x 23m x 286.5m is located with the core of the ridgeleft bank (max. EL 780m) forming water divide between Rollegad Nallah in the southand another unnamed nala in the north. The crown and invert are kept at EL.454.80m and 397.50m respectively. The ground elevation in the ridge line variesfrom El 670m to 780m and accordingly the vertical burden above cavity crown variesfrom 167m to 325m. The lateral cover towards Mahakali River varies from 210 to260m. The UGPH area consists of three litho- units viz. Micaceous quartzite withbands of granitized schist (Mqtz), Quartz- biotite gneiss (Qbg) and Augn gneiss(Augn); the Mqtz occurs in the central part of the cavity. Whereas the Qbg and Augnare exposed in the NW and SE parts respectively. These strike in N70°W-S70°E anddip 80° in S20°W. Thus the long axis of the cavity is oblique to the foliation withinternal angle of 50°. Two new holes NDH 9 and NPH 02 were recently a drilled byWAPCOS in the vicinity of UGPH. The drill core results revealed that with depth therockmass improves and rock quality Q value also increases. The core results revealthe UGPH will be drive in fair to good rockmass condition. The Q value varies 1.5 to7.5 in NDH-9 and 1.8 to 10 in the NPH-2.

Based on review of the subsurface explorations, the dam site regime has beenclassified into two units viz. (a) the core zone of the abutments below El 550m (i.e.vertical cover of 200m) and lateral cover of 100-150m and (b) surficial cover aboveEL550 (vertical cover <200m) and lateral cover <100m. Thus, in view of large vertical(>300m) and lateral cover (>200), the powerhouse cavity in Nepal side lies in thecore zone. Accordingly, the litho-units in UGPH domain have been geo-mechanicallyclassified assigning RMR base for Augn, Mqtz and Qbg litho-units.

The intake of the Power tunnel (3Nos -Ø8.7m) is proposed 650m U/S of the Rockfilldam axis. Geological section has been drawn to illustrate ground conditions basedon geological map and subsurface data projected from nearest drill holes located onadjoining appurtenants viz drill hole NDH-12, SDH-1 and NPH-2 and D-15. Theinitial part of the power tunnel trend sub- parallel to the strike of the formation of thearea and further swerves towards south and then SW to enter the UGPH cavity. Thetail race tunnel ensuing from surge chamber, trends in south-west direction to carrydischarges back to south-easterly flowing Mahakali River. The proposed PT systemnegotiates across litho- unit’s viz. Qfms, Mqtz and Augn. At the distal end of the TRTthe second band of the litho-unit Qfms is exposed. These are traversed by multipleof discontinuities.

The vertical cover, excepting for initial and terminal reaches, is > 200m ranging to amaximum of 390m. Geological section has illustrated ground conditions along PT-



TRT system based on geological map. As seen from the section, the dominanttunnelling ground for PT is the disturbed blocky rock mass of Qfms. Minor bands ofQbg, Mqtz and Augn would also be intercepted. Considering vertical and lateralcover, litho-units likely to be encountered, angle between trend of the proposedorientation of the tunnels and foliation, vertical cover above the tunnel grade andlateral cover over the PT-TRT system, it has been classified into seven segments.

1.3.3.7 Geology of UGPH on Right Bank (India Side)

The UGPH (H x W x L) 57.3m x 23m x 286.5m on India side is located in the corezone of the abutments with vertical burden 159-353m and lateral cover of >245m.The modified orientation of long axis of the cavity (N54°E-S54°W), is nearly 50°oblique to the main direction of stresses and oblique to foliation (56°). The cavitydomain has been explored by 360m long drift also; however, 3D logs are availablefor 270m. The drift has intercepted Mqtz with four numbers of foliation parallel minorshear seams. It would be worthwhile to excavate cross cuts and conduct in-situ testsfor further rock mechanic characterization. For preliminary evaluations, a schematicgeological section of the UGPH cavity domain has been developed based ongeological comprehension based surface based geological map. It is seen thatUGPH and associated cavity are located within 450m wide bands of micaceousquartzite associated with granitized mica schist. The quartzite rock mass isattributed with GSI values of 55-65. The Rock mass classification in core zone of themountain can be taken from attributing these with RMR 41 to 60. Considering these,the excavation response in the cavity has been evaluated following simplifiedprocedure of Russo (2007).

The excavation response in case of PT/ TRT tunnels has been dealt with, in generaldescribing the broadly expected rock mass condition and tunnelling issues for wantof precise subsurface data. The right bank has been taken up for detailedassessment with the help of drill hole NPH-1 which has been drilled recently inpower house location falling close to middle reaches of the tunnel. Importantsubsurface data from a few older drill holes have also been imported for the sake ofthe incorporation of potential weak zones of significant thickness and long distancecontinuity with possibility of intersecting the tunnel e.g. the shear/ fracture zones of12m and 14m thickness encountered in drill holes A1/2 and A2/6 respectively in riversection. The different lithological zones have been ascertained with their severalgeotechnical attributes albeit with limitation for want of rock conditions at tunnelgrade. Of these, initial, middle and end reaches are of significance. Initially along astretch of 570m, the tunnel alignment runs oblique to foliation cleavage/ foliation jointplanes. Middle 800m long reach strikes these master discontinuities at an acuteangle of around 300 and remaining end reach of 600m length is transected byfoliation at right angle.



1.3.3.8 Geology of Diversion Works- Tunnels and Coffer dams

A geological section has been developed for DT No. 2 having 2733.00m long, 14mdia. circular shape on the left bank. The inlet and outlet portals are proposed at anEl. of 410.0 m and El. of 397.0 m respectively. The diversion tunnel is locatedbetween an area 2073.15 m upstream and 732.72 m downstream of Rockfill damaxis on the left bank. The upstream coffer dam would be located about 910.0m(along centerline of River) upstream of rockfill dam axis with a dam top El. of 461 m.Similarly, the downstream coffer dam will be 550.0 m (along C/L of River)downstream of the rockfill dam axis with dam top El. at 436 m. The diversion tunnelalignment is traversed by two nallah at RD 111.74m and 1766.3m. The nallah at RD1766.3m is deeply incised which can possibly be structurally controlled and could bethe source of water seepage in the diversion tunnel. The rock cover above thediversion tunnel is estimated around 96-227 m at between RD 200 to 2690m. Thediversion tunnel corridor on the left bank with lateral cover ranging from 73.96m –744m. The initial 887.9m would have Augn gneiss (Augn) as tunnelling ground. Theunits Quartz feldspathic mica schist (Qfms) and Quartz biotite gneiss (Qbg) would beintercepted between 887.9- 2067m and 2067-2225m. The unit’s micaceous quartzite(Mqtz) & Augn gneiss (Augn) would be intercepted between 2225-2338m and 2338-2788m sections, respectively. The remainder of the tunnel would have Quartzfeldspathic mica schist (Qfms) as tunnelling ground.

On the right bank, a geological section has been developed for DT No. 4 having2504.00m long, 14m dia. circular shape. The inlet and outlet portals will be located atan El. of 410.0 m and El. of 397.0 m. The diversion tunnel is located between anarea 1582m upstream and 922m downstream of Rockfill dam axis on the right bank.The upstream coffer dam is about 910.0 m upstream of rockfill dam axis with a damtop El. of 461 m. Similarly, the downstream coffer dam is about 550.0 m downstreamof the rockfill dam axis with dam top El. at 436.0 m. The diversion tunnel alignment istraversed by five nallah at RD 536m, 686m, 1299m, 1684m and 2378m. The nallahat RD 2378m is deeply incised which has possibility of water seepage in thediversion tunnel. The rock cover above the diversion tunnel is around 38-275 m atbetween RD 200 to 2495m.The DT system would have lateral cover ranging from85-512m. Approximate rock mass quality estimates and assessment of overalltunnelling condition has been attempted zone wise based on the surface andsubsurface geological projections.

1.3.3.9 Geology of Rupaligad Dam Site and Spillway

A 95m high concrete gravity dam is to be located on an intercalatory sequence ofQuartzite and Mica schist, dominated by the former. The quartzite is whitish grey,medium grained and strong (GSI 60 to 70). The Mica schist is greenish grey to lightgrey, fine to medium grained, well foliated and weak to moderately strong (GSI 35 to



45). Foliation runs almost parallel to slightly askew to dam axis with moderate dipspredominantly towards upstream. Major joint sets mostly exhibit a favourableorientation. From subsurface exploratory data, it is evident that the thickness ofoverburden is maximum 5m on abutments and slightly weathered to fresh rockoccurs either just below the overburden or a couple of metres beneath. Howevermost of the drill hole sections are conspicuous of frequent nil to low RQD zones. Thedam foundation is not homogeneous as the competent quartzite is often associatedwith Mica schist bands of up to 10m thickness. This intercalatory association ofalternating foundation media of differing strength parameters renders the foundationheterogeneous. It will be reasonable, therefore, to design the foundation on thestrength of weaker foundation rock to avoid possibility of differential settlement andavail the competence of stronger foundation rock as an additional advantage. Overall permeability values vary between Lu<1 and 43. But more commonly the highervalues are restricted around 20-30Lu only. The permeability tends to decreasegradually with depth but reversal and deviation from this trend are also recorded. Asobserved in drill hole core, both the Quartzite and Mica schist are fairly well fracturedwith variations in core recovery and considerable fluctuation in RQD within theenvelope of low to moderate RQD. In general, with spot specific modifications, rockcut slopes of 600 and 650 are likely to be stable on abutments with the correctivemeasures.

A centrally located bucket type, gated spillway with crest level at 386.00m isproposed to pass a maximum flood discharge of 27,700 m3/s at the Rupaligad damsite. It is 192.00m long along the dam axis with downstream extension of around200m up to the end of plunge pool as a part of energy dissipation arrangement. It isto be founded on a heterogeneous foundation consisting of relatively competentQuartzite (RMR 56-67 and GSI 60-70) with weaker intercalations of Mica schist(RMR 35-51and GSI 35-45) as depicted by all the drill holes drilled in Dam/ spillwaydomain. Deepest foundation in the river bed as depicted in case of the main dam isanticipated at a depth of around 35m (EL 335m).The maximum depth in the river bedfor the foundation of all concrete structures including the appurtenant for energydissipation has to be lowered down to bedrock underlying a maximum pile of 33mthickness of RBM. On left bank, a stripping of 12 t0 16m deep (EL 378m to EL 382m)from the surface will be enough to rest the foundation. The same 3m thick shear/fracture zone intersected in drill hole DH-3 may encroach upon the dam foundationon the left bank in spillway section required dental treatment attendant with contactgrouting and provision of drainage holes. This is a foliation shear and is likely tostrike the dam length at a low angle (150 to 200) crossing the dam body for aconsiderable length. On right bank maximum excavation to a depth of 10m to16m(EL380m to EL 365m) is foreseen. As projected in drill hole DH-2, a one m thickshear zone is anticipated to encroach upon the downstream toe part of damnecessitating dental treatment as mentioned in respect of left bank shear zone. Thisis also a bedding shear and may intersect dam length at a low angle.



1.3.3.10 Geology of Rupaligad UGPH on the Left Bank (Nepal Side)

A power house cavern with dimension of 24.00m X 49.50m X 112.00m (W/H/L) isproposed on the left bank of the river at Rupaligad site between the elevation of338m and 388.50m with a vertical cover of 146m and lateral cover of around 136m.The transformer cavern has been located at about 48m away to obviate mutualinterference of lateral stresses. This extent of rock participation between the twocaverns of respective width of 24.00m and 19.00m should be duly analysed fromtunnel stability point of view to avoid instability emanating from mutual interference ofthe lateral stresses. The cavern will be excavated in moderately strong to strongquartzite with intercalatory weaker bands of garnetiferrous mica schist. These schistbands may form significant horizons of relatively weaker strength for a thickness ofup to 10m. They are repeatedly found as intercalations in Quartzite in drill hole coreof dam axis area. The longer axis of power house cavern was fixed in N150W-S150E (N3450) direction at an angle of 600 from foliation strike. The vertical cover of140m does not rise any possibility of encountering squeezing condition in softer Micaschist bands during excavation. The rock mass characterization carried out insurficial outcrops of Quartzite and drill hole core in adjoining part is indicative ofRMR value of 45 to 57 and GSI 60 to 70 (Fair to Good rock). In respect ofgarnetiferrous Mica schist/Mica schist, it varies between RMR 35 to 50 and GSI 35 to45 (Poor to Fair rock). Based on the extrapolation of these data, the rock massquality in proposed power house cavern is indicative largely of “Poor” to “Fair” and“Good” tunnelling media. Stereographic projection and wedge analyses indicatesthat Joint plane J1^J3, J1^J4 and J1^J5 form wedges with moderate to steep plungein vulnerable direction. Similarly, joint planes J2^J4, J2^J5 and J3^J4, J3^J5 alsoproduce intersecting wedges on the wall of cavern with moderate plunge on the wall.

Twin Tailrace tunnels of 7m dia and 56 m length are to be excavated with 18m wideintervening column of rock mass. The tunnels extend in S75OW direction strikingfoliation at an angle of 300. They are to be driven through moderately strongQuartzite ( RMR 50-60 ) with intercalated bands of soft and weak Mica schist (RMR35-43) designating the rock mass largely as Fair-Good Rock with poor reaches inMica schist. TRT out fall is to be founded on competent quartzite exposed on thesurface. Foundation grade is likely to be available here at a very shallow depth.Steep rock cut slopes are foreseen to be stable at outlet portal of TRT withShotcreting and selective rock bolting.

1.3.3.11 Geology of Rupaligad UGPH on the Right Bank (India side)

The power house cavern on right bank with dimension of 24.00m X 49.50m X112.00m (W/H/L) is proposed between the elevation of 338 and 388.50m. The NSLabove the cavern is EL 538m. The power house cavern is thus confined under avertical and lateral rock cover of 150m having optimum rock participation from either



direction. It is to be located in moderately strong to strong quartzite with relativelyweaker intercalatory bands of garnetiferrous mica schist. The presence of theseschistose bands of up to 10m thickness as observed in proximity to dam seat maydenigrate the overall quality of rock mass in power house cavity. Actual presence ofany significant weak zone traversing the power house and transformer hall cavernscan be further ascertained after the completion of subsurface exploration by drifts.So far, the available data do not reveal any possibility of extrapolated weak zonecrossing these underground structures. Thus the power house cavern axis strikesthe general foliation trend at an angle of 750. The vertical cover of 150m rules outany possibility of encountering squeezing condition in softer Mica schist bandsduring excavation. The rock mass characterization based on surficial outcrops anddrill hole data from adjoining area is indicative of RMR of 50 to 63 and GSI 60 to 70(Fair to Good rock) in Quartzite. In respect of garnetiferrous Mica schist/Mica schist,it varies between RMR 35 to 50 and GSI 35 to 45 (Poor to Fair rock). Based on theextrapolation of these data, the rock mass quality in proposed power house cavern isindicative largely of “Fair” and “Good” tunnelling media with localised bands of Poorto Very poor rock mass.

Further, 92m long twins Tail Race Tunnels of 7m dia. are contemplated in N600W-S600E direction, almost sub parallel to parallel of foliation cleavage/joint. The tunnelwill be driven predominantly through moderately strong Quartzite (RMR 45-55) withintercalated bands of weaker Mica schist mostly with orientation specific poor rockmass characteristics (RMR 30-38). Outlet portal back slopes are gentle and likely tobe stable with minimum remedial measures. TRT outfall is located on overburdencomprising slope wash material of sandy-silty soil and talus boulders. A drill hole isproposed (DH-28) to probe the overburden thickness and evaluate foundation foroutfall.

1.3.3.12 Geology of Diversion Works- Tunnels and Coffer dams atRupaligad site

The bearing of 1023m long 12m dia proposed diversion tunnel on the left bankshows two kinks along the alignment. The tunnel is to be driven through moderatelystrong to strong Quartzite with intercalated subordinate bands of Mica schisttraversed by several sets of discontinuity. The tunnel is to be driven throughmoderately strong to strong Quartzite with intercalated bands of Mica schisttraversed by several sets of joints. The Quartzites are characterized by RMR 45 to63 (Fair to Good Rock). However, the intercalated Mica schist bands, which are upto 10m thick, denigrate the overall rock mass quality. These bands in addition toremaining 40% rock mass along the tunnel alignment constitute weak tunnelingmedia characterized by RMR 30 to 45 (Poor to Fair Rock mass). The averagefoliation trend of rocks is N750 W-S750E with a dip of around 500 towards N150E i.e.towards upstream of the tunnel. If tunnel is driven from outlet portal side, nosignificant adversely oriented wedges are anticipated at crown along all variations in



tunnel alignment. Joint planes J2^J5 only form wedge near crown with a shallowplunge. Mainly top heading and benching with short advances will be applicable astunnelling method.

Another 958m long and 12m dia diversion tunnel is proposed on the right bank. Itsalignment is also punctuated by three kinks. As per the projection from surfacegeological map more than 70% of the tunnel excavation is to be accomplished inmoderately strong to strong quartzite with intercalated bands of Mica schist,predominated by the former. Remaining 30% rock mass is likely to consist mainly ofweak to moderately strong Garnetiferrous Mica schist with thinly interbandedquartzite. A 50cm thick foliation parallel shear zone has been inferred at around RD260m in Mica schist below Kharagnala. Very poor rock conditions are expected inthis zone for a short stretch of a few meters. The foliation strikes the veering tunnelalignment at an angle of 320 to 750. According to rock mass quality estimates, theQuartzite is characterized by RMR 45 to 65 (Fair to Good Rock), intercalated Micaschist horizon by RMR 35 to 45 (Poor to Fair Rock) and Shear/ fracture zone byRMR 15 to 20 and GSI 20 to 30 (Very Poor Rock). The maximum vertical rock coverover the tunnel is 234m abstaining squeezing possibility in Mica schist horizon due toconvergence.

A 24m high and 163.0m long rock fill coffer dam with an impervious clay core andupstream concrete face is proposed at 148m upstream of main dam axis. Theupstream cofferdam area is occupied mainly by garnetiferrous Mica schist with thininterbands of Quartzite. The maximum depth of bed rock in river section to found thecore is likely to be of the order of 32 to 35m. Construction of coffer dam on riverineoverburden after consolidation by high pressure jet grouting may be considered toavoid deeper excavation for founding the impervious core.

A 17m high and 110m long rock fill dam is proposed at about 200m downstream ofthe main dam. Competent Quartzite with intercalatory Mica schist is available oneach bank almost at surface or at a very shallow depth. However, in the riverbed,which will accommodate the maximum length of the dam, the bed rock is anticipatedto be available at a depth of a couple of meters on the river edge to as much asabout 33m in the deepest channel bed beneath a thick pile of riverine sediments..

1.4 Sedimentation

1.4.1 Pancheshwar Reservoir

The average sediment rate of last 26 years data (1983 to 2013 with gaps) has beenconsidered along with the depth integrated sample sediment rates obtained for theperiod 1990 to 1992. The average sediment rate of these values excluding the year2007 is 3.42 mm/year including 20% as bed load. The annual sediment load atPancheshwar dam site has been estimated 41.98 Million m3.



The Full Reservoir Level of 680 m has been finalized and sedimentation studieshave been carried out with this level only. Trap efficiency of the reservoir has beencalculated by Brune's method and sedimentation distribution in the reservoir hasbeen done using the Borland and Millar Empirical Area Reduction Method. The resultof the study such as the percentage loss of gross storage, live storage and deadstorage after 25, 50, 70 and 100 years of sedimentation have been described indetail in relevant sections.

During the first 100 years of operation of the reservoir, the trap efficiency will be ofthe order of 96% and the material that is not decanted in the reservoir may gothrough the turbines. The un-trapped annual sediment load amounts to about 1.16million cubic metre, which corresponds to a sediment concentration of about 63 ppm,indicating turbidity nearly acceptable as drinking water.

1.4.2 Rupaligad Re-regulation Reservoir

The annual trapped volume of sediment in Rupaligad reservoir has been estimatedto be more than 0.5% of the gross capacity of reservoir. As per IS Code No. 12182 -1987 "Guidelines for determination of effects of sedimentation in planning andperformance" the problem of sedimentation was treated as serious. To deal with thesediment load from the Rupaligad catchment, sluice spillway has been provided atRupaligad dam. During monsoon, major sediment load would be flushed in thedownstream through sluice gates.

1.5 Construction Materials

1.5.1 Materials Survey

Field investigations to assess the availability of different types of constructionmaterials in the vicinity of the project area had been carried out by India and Nepalseparately and also jointly by them. The first field investigations were carried out byIndia to locate a source of impervious core material for the earth-rockfill dam. Threeborrow areas for impervious material, three borrow areas for fine sand and fourborrow areas for boulders cum sand were located in the Indian Territory during 1983-84. Between 1989 and 1991, field investigations were carried out by the Nepaleseside to obtain a preliminary assessment of the availability of construction materials inNepalese territory. In 1993, India and Nepal conducted joint field investigationsprimarily in India, although some samples were collected from Nepal areas also.

As a part of additional field investigation and studies, JPO-PI entrusted the work ofconstruction materials investigation and rock mechanics tests to Central Soil andMaterial Research Station, New Delhi (CSMRS) to ascertain the quantity & quality ofimpervious core material and rockfill material for the main dam. CSMRS had carriedout field investigations for core material in 2001-02 and thirty two representative bulksoil samples were collected for laboratory testing on Indian side. Tiger quarry on leftbank and big Elephant Quarry on right bank were explored for shell material.



1.5.2 Materials Requirement - Pancheshwar

The Table 1.5-1 below summarizes the volumetric requirements for rockfill dam atPancheshwar and source of the materials in the vicinity of the project site.

Table- 1.5-1: Construction Materials Balance – Pancheshwar

Material Type ofStructure

Requirementof Material

(Mm3)

Source ofMaterial

Availabilityof Material

(Mm3)

Distance fromdam (km)

ImperviousSoil

DamImpervious

Core13.18

Patan (Nepal)Rato-Mato(Nepal)Pulhindola(India)Harkhera(India)

14.3626.60

38.04

17.29

64 km30 km

15 km (by road)

10 km (by road)

Sand andcoarseaggregate

Filter 4.69RequiredExcavationBinayak(Nepal)Kharyani(Nepal)River Bed

1.54

8.47

1.65

1.10

-

9 km

30 km

-Shellmaterial

Rock fill +River bed +

Rip rap

120.00 RequiredExcavationTiger Quarry(Nepal)LeopardQuarry (Nepal)River BedElephantQuarry (Nepal)

57.45

Unlimited

Unlimited

14.90Unlimited

-

2 km

15 km

4 to 5 km2 km

Coarseaggregate /Crushedsand

Concrete 2.88

1.5.3 Laboratory Tests - Pancheshwar

CSMRS, New Delhi carried out laboratory testing of samples collected during thefield investigations taken up by JPO-PI. Suitable impervious material with most of theabove characteristics is available from the Harkheda borrow area. The sand andgravel materials from which the filters will be processed will come from requiredexcavations in the river bed as well as from terrace deposits along the river, inparticular the Binayak Borrow Area, about 6 km upstream of the dam. The materialfrom Tiger quarry and Spillway excavation will be utilised for shell material.

With a few exceptions, there exist in the vicinity of the dam site constructionmaterials of sufficient quality and quantity to construct the proposed rock fillembankment and appurtenant structures.



The rock available from Tiger quarry, Binayak quarry, River boulder quarries,Diversion tunnel (Nepal side), Spillway (Nepal side), Swillghad village and GhoriaNallah are found suitable for use as coarse aggregate in concrete for non-wearingsurface only.

Therefore, WAPCOS Ltd investigated further area and finally located a rock quarryfor use of coarse aggregate in concrete, two km below the dam axis (Tiger Quarry)on the Nepal bank suitable for the wearing surface.

The water samples were also collected near Pancheshwar dam site from the riverSarju and river Mahakali by CSMRS team for testing to use the river water forconcrete structures.

1.5.4 Materials requirement for Rupaligad dam

Approximately 1.25 million m3 of coarse aggregates will be required for constructionof Rupaligad dam and its appurtenant structures. For this purpose, WAPCOS hascarried out survey and located a rock quarry near the Rayal village which is suitablein all respects for use as coarse aggregates in concrete for wearing as well as non-wearing surfaces. The aggregates from the rock quarry near the dam axis will beused for non-wearing surfaces only, if required.



1.6 Seismicity

The site for Pancheshwar Project lies within the most complex tectonic belt, the MainHimalayan Belt. It is bounded by the MCT in the north (65 km) and MBT in the south(25 km), both of which are believed to be presently active. Pancheshwar dam is torest over rocks belonging to Almora Crystallines/ Dadeldhura (Proterozoic),interpreted as a nappe structure confined between the North and South AlmoraThrusts.

A seismo-tectonic review of the project area reveals that the site lies in a hyperactiveseismic environment. The project area forms part of the Main Himalayan SeismicZone. The seismic activity has been related to the under-thrusting Indian Plate belowthe Lesser Himalaya and is found concentrated along the detachment surface, MCT,and the basement thrust. A seismically active belt striking north-northwest over alength of about 1.10 km and located about 80 km northeast of the dam site wasuncovered by the micro-seismic investigations carried out.

The Rangun Khola Fault, located approximately 30 km south of the dam site, isconsidered to be the most critical source of seismic activity for the project. For suchmaximum credible earthquake, different attenuation models applied led to estimatesof the maximum peak acceleration at the site ranging from 122 to 256 gals. On theother hand, a statistical analysis of the available historical records gave peakaccelerations of 90 gals for a return period of 100 year and of 104 gals for 200 yearswith the most conservative attenuation model considered.

Reservoir induced seismicity is not considered a problem for the project.

The magnitude of Maximum Credible Earthquake (MCE) is estimated to be 8.1. Onthe basis of the tectonic features in the vicinity of the project site and the distributionof the hypocenters of past-earthquake, the closest distance of the fault rupture planefor MCE is estimated as 39 km. In order to review the seismic design parameters ofthe project, CWPRS, Pune was assigned the study and they have recommendedhorizontal coefficient 0.24 and vertical coefficient 0.16, for the dynamic analysis ofthe Pancheshwar project.

1.7 Infrastructure and Communication Survey

In order to transport the generating units to Pancheshwar, a new road capableof transportation of over sized consignments of electro-mechanical equipmentwas envisaged on left bank on Nepal side from Brahmdev – Kancheshwar -Rangun Khola – Simatta – Sirsha – Rupaligad – Dhamkudi – Pancheswar. Theoversized consignments will be transported on 16 axle Trailers, for which 15 mwide road has been planned with a turning radius of 25 m at critical bends.

The total length of new road has been assessed 90 Km from Brahmdev toPancheshwar via Rupaligad dam site, involving about twenty minor and major



bridges of spans from 50 m to 600 m. A major bridge across Rangun Khola(600 m span) and a tunnel of 2.0 km in length at Simalta village are alsoproposed to reduce the length of road by 8 km.

1.8 Benefit Assessment & Project Optimization

1.8.1 Power Market Review

In order to evaluate the potential for the Project to sell all the energy producedfrom the time of its commissioning, a review of the latest available power marketforecasts and power system expansion plans for northern India and Nepal hasbeen carried out. Data on the power market and power system of Northern Indiahas been taken from Central Electricity Authority, India; for the power system ofNepal from the latest official documents made available by Nepal ElectricityAuthority, Nepal.

1.8.2 Power and Energy Benefits

Reservoir simulation studies have been carried out to compute the firm power(MW) and annual energy production (GWh) from the Pancheshwar MultipurposeProject with re-regulating dam at Rupaligad site. The Pancheshwar powerhousewould operate in the interest of power generation while protecting downstream irrigationrequirement and would provide peaking benefits.

The Rupaligad pond would store the peaking outflows from Pancheshwar PowerStations and re-regulate them to provide continuous river flows to meet the irrigationwater requirement downstream.

FRL for Rupaligad re-regulating dam has been adopted as + 420 m considering tailwater level of Pancheshwar Power Houses. The MDDL for Rupaligad wasconsidered as 400 m, with a view to provide the diurnal storage of 56 Million m3.

For carrying out the simulation studies, water requirement of local communities @5% of the annual average flow at Pancheshwar dam site was reserved and notconsidered for the power generation. The downstream irrigation water requirementshave been protected from Pancheshwar reservoir after taking into account theadditional water available from the intervening catchment between Pancheshwar andthe Tanakpur barrage.

The results of the simulation studies indicate the firm power at Pancheshwar as 767MW as shown in the Table 1.8-1 below. The annual energy benefits are assessed as7678 GWh on 90% dependable basis with a total installed capacity of 4800 MW intwo power stations, one on each bank of the river (six units of 400 MW in eachpower house). The proposed installation would enable operation of the station toprovide four hours daily block of peaking capacity and the stations would operate ata load factor of 15-16%.



In addition, the annual energy generation benefits from Rupaligad dam would be inthe order of 1438 GWh on 90% dependable basis. An installed capacity of 240 MW,comprising two units of 60 MW each are proposed in each of the two power houses;one on left bank and the other on right bank of the river.

Table 1.8-1: Annual Energy Generation

PancheshwarInstalledCapacity

(MW)

Annual Energy Generation (GWh)90% Dependable year Study Period Average

Pancheshwar Rupaligad Total Pancheshwar Rupaligad Total

3200 7678 1438 9116 10063 1559 116223600 7678 1438 9116 10180 1559 117384000 7678 1438 9116 10248 1559 118064400 7678 1438 9116 10299 1559 118584800 7678 1438 9116 10327 1559 118855200 7678 1438 9116 10349 1559 119085600 7678 1438 9116 10366 1559 119256000 7678 1438 9116 10375 1559 119346400 7678 1438 9116 10375 1559 11934

Based upon the cavern width of 23 m and transport considerations, the units size atPancheshwar have been selected as 400 MW.

1.8.3 Irrigation Benefits

1.8.3.1 Existing consumptive uses of Nepal and India

Banbasa Barrage

The waters of Mahakali River are being utilized for irrigation in India since thecommissioning of Banbasa Barrage in 1928. Some Terai area in Nepal has alsobeen benefited by the Mahakali waters drawn from the Banbasa Barrage.

In accordance with the earlier agreement of 1928, Nepal is entitled to draw 28.35m3/s (1000 ft3/s) of water in monsoon season (from 15th May to 15th October) and4.25 m3/s (150 ft3/s) in the dry season from the Banbasa Barrage. This water drawnfrom Banbasa Barrage provides irrigation to a command area of 11,600 ha; 4800 haunder MIP stage-I and 6800 ha under MIP stage-II in Kanchanpur district of Nepal.

For providing the irrigation facilities to India, a canal on right bank with 326 m3/s(11,500 ft3/s) discharge capacity for India and another canal on left bank with 28.35m3/s (1000 ft3/s) capacity for Nepal were constructed by signing an agreementbetween British India and the King of Nepal in 1920.



Tanakpur Barrage

Another barrage at Tanakpur, about 10 km upstream of the Banbasa barrage wasconstructed in 1985 by M/S National Hydro-electric Power Corporation of India,across river Sarada, in India to generate power. For commissioning of the TanakpurHEP, an agreement was reached between India and Nepal in 1991 which wassubsumed in the Article-2 of the Mahakali Treaty.

Under the Article-2 of the Treaty, Nepal is entitled to receive 28.35 m3/s (1000 ft3/s)water in the wet season and 8.50 m3/s (300 ft3/s) of water in the dry season from theTanakpur Barrage. A new canal of 28.35 m3/s (1000 ft3/s) discharge capacity hasbeen constructed from the Tanakpur Barrage, under the grants-in-aid assistance bythe Ministry of External Affairs, GOI to supply additional water to Nepal.

Lower Sarada Barrage

In the early seventies, the State Government of Uttar Pradesh (IrrigationDepartment) commissioned another project known as Sarada Sahayak Pariyojna(System) in district Lakhimpur Kheri of Uttar Pradesh. The original command ofSarada canal system, lying East of Sarada Sahayak Feeder was deleted from theSarada canal system and transferred to the Sarada Sahayak system in 1975.

The Sarada Sahayak system with design discharge of head works as 650 m3/sdraws irrigation supplies from the Lower Sarada Barrage, 160 km downstream ofBanbasa Barrage, during monsoon season and dependent on the Mahakali watersfor meeting the irrigation requirements in the lower command area (20 lakh ha).

The inflows in the Mahakali River during the monsoon season are sufficient to meetthe existing water requirements of India and Nepal at Banbasa, Tanakpur and LowerSarada barrages.

1.8.3.2 Existing Use of Nepal for Irrigation

The existing consumptive uses of Nepal are thus, agreed under the Article 1 & 2 ofthe Treaty in a year as 451 MCM from Banbasa barrage and 529 MCM from theTanakpur Barrage respectively. Total existing use of Nepal is of the order of 980MCM per annum

1.8.3.3 Existing Water Use of India for Irrigation

Total existing water requirement of India comprise of (i) Existing Water Requirementof Sarada canal system throughout the year and (ii) Existing Water Requirement ofSarada Sahayak system for monsoon period. The existing water use of India throughUpper Sarada Canal system and Sarada Sahayak system are of the order of 7,071MCM & 4,790 MCM respectively totalling to 11,861 MCM per annum.



1.8.3.4 Irrigation Benefits from the project

Irrigation benefits in Nepal have been assessed on the basis of the previous studieson the proposed irrigation area in Nepal from the project, illustrated in the report ofPancheshwar Consortium (PACO)-1991 on Field Investigations within NepalTerritory.

Irrigation benefits in India have been assessed on the basis of evaluation of surplusaugmented flows available during dry season after meeting requirement for existingirrigation in India and Nepal as well as additional irrigation in Nepal. For this purposemaximum additional irrigation that is techno economically feasible in Nepal fromMahakali river has been considered.

A 75% dependable year criteria has been used for defining the available waterresources. Depending on the availability of sufficient regulated water in the MahakaliRiver, a total command of about 93,000 ha could be developed in Nepal betweenMahakali and Karnali.

1.8.3.5 Future Water Requirement of Nepal

Under the Article-4 of the Treaty, India shall supply 10 m3/s (350 ft3/s) water forirrigation of Dodhara – Chandani area of Nepalese Territory. Further, as per theArticle-5 of the Treaty, water requirements of Nepal are given prime consideration inthe utilization of the waters of the Mahakali River. With the availability of augmentedflows in the post-Pancheshwar scenario, it has been assessed that a maximum croparea of 170,720 ha can be brought under irrigation (including 6,040 ha of Dodhara-Chandani area) in Nepal with the available additional water on implementation ofPancheshwar Multipurpose Project. For development of this command, additionalwater requirement will be of the order of 3,073 MCM. Thus, total water use by Nepalwill be 4,053 MCM comprising of 980 MCM as existing use and 3,073 MCM as futureuse.

1.8.3.6 Future Water Requirement of India

Additional Irrigation in India from Pancheshwar Multi-purpose Project has beenconsidered during dry season only as enough water is available in Sarada River forirrigation in existing commands during monsoon even for without Project scenario.Considering the power releases from Pancheshwar and water available in theintervening catchment from Pancheshwar to the Tanakpur Barrage, after meeting theexisting requirement of Nepal and India and future requirement of Nepal, additional1,905 MCM of water would be available to India in the post-Pancheshwar scenario.With the additional water to India, annual irrigation may be enhanced by 2.59 lakhHa. Thus, total water use of India will be of the order of 13,766 MCM onimplementation of Pancheshwar Multipurpose Project. A detailed statementindicating the total water requirement of India and Nepal is given in the Table 1.8 -2.



1.8.4 Flood Control Benefits

Since no dedicated storage is proposed for flood control, benefits on account ofreduced floods are incidental. The average annual value of the potential flood controlbenefits in Nepal was computed through a statistical analysis of the annual flooddamages with and without the project along the 50 years economic life of the plant.Without the project, the average annual flood damages in Nepal were computed toreach 0.81 million US$, that would be reduced to 0.15 Million US$ per year after theproject implementation as stated in the draft Indian DPR of 2003. WAPCOS hasreviewed the potential annual flood control benefits in India and Nepal; andestimated INR 740 million and INR 160 million respectively, at 2015 price level.

Thus, total annual flood benefits in the post Pancheshwar scenario would be of theorder of INR 900 million at 2015 price level.

1.9 Design of Civil Structures of Pancheshwar MultipurposeProject

The course of the River Mahakali in its upstream reaches is characterized by verysteep drops both on the main river and its tributaries. In its middle and lower reachesit flows through relatively gentle gradients providing a good scope for a storageproject. Accordingly, in the preliminary studies, various sites were considered forlocation of a storage dam project just downstream of the confluence of river Mahakaliwith Sarju. The dam site was selected in view of the narrow gorge flanked by highrising hills and gentle gradient. In the present study, the same site was studiedfurther for the Pancheshwar Multipurpose Project which consists of main dam and are-regulating dam at Rupaligad, around 27 km downstream of Pancheshwar dam.

1.9.1 Pancheshwar Dam

A considerable area around the proposed dam site had been investigated in the pastby India and Nepal in detail, to explore the surface as well as subsurface geology ofthe dam site and to locate a suitable dam axis. The investigations were carried outby drilling a number of bore holes and drifts in different phases of projectinvestigation; the details of which are included in the relevant sections of the report.

1.9.1.1 Concrete Dam Axis

In the initial studies, a dam axis (shown as “CC” on the map below) was exploredduring the period from the year 1964 to 1971 by excavating 12 drifts and eightinclined drill holes for locating a 247 m high concrete gravity dam. Geologicalinvestigations were continued further on this axis by conducting drill holes beyondthe period 1983 by the Indian side to ascertain the depth of stripping in theabutments. It was transpired that sound rocks are available in the abutments at avarying depth of 30 to 60 m. In general, the depth increases in the upper reaches inthe left abutment. Besides blocky and jointed nature of the strata in the different



zones, the shear zones form an integral part of the rock.

With subsequent change in favour of a higher dam with top elevation around + 688m, the axis CC got dropped in the project layouts, not only because of the geologicalproblem indicated above but also due to the limited elevations of the left abutmentcrest which itself being at about dam top elevation. An alternative axis “BB” wasselected for concrete dam, 115 m upstream of axis CC. The new axis had thetopographical advantage of allowing construction of a higher dam. The bore holesdrilled at the crest of the left abutment indicated availability of good foundation rockat elevation + 706 m, 18 m above the dam top, thus getting over the geologicalproblem for accommodating a higher dam.

1.9.1.2 Rockfill Dam Axis

A dam axis for rockfill dam was also investigated around 360 m upstream of axis CCand mentioned as axis AA in the map, so that the d/s toe of the rockfill dam isaccommodated within the gorge section, upstream of major cross drainage joiningRiver Mahakali from left and right flanks and the dam body did not extend tocomparatively weak Quartz Mica Schist, but limited to the Augen Gneiss. Onphysiographic consideration, the rockfill dam axis was marginally adjusted andshifted 30 m downstream later on referred to as the axis DD on the map.

After 5th meeting of the Joint Group of Experts held in March 1991, it was decided tocarry out geotechnical investigations jointly covering the river bed, abutments andthe underground power house locations on both banks of Mahakali River. It includeddeep drill holes and extension of drifts up to the power house locations. Geophysicalsurveys at diversion tunnel intakes and head race tunnel intakes were alsoundertaken to finalize the project layout of Pancheshwar rockfill dam and itsappurtenant works. In-situ rock tests and laboratory tests on rock samples wereconducted to determine the rock mass characteristics in the foundation of the damand underground power house caverns.

Thus, four alternative dam axes at Pancheshwar were investigated in the past; whichare designated as axis AA, BB, CC and DD and shown in the Figure 1.9-1:



Figure-1.9-1: Map showing the location of dam axis AA, BB, CC and DD

In accordance with approved Terms of Reference (ToR) for review of the Rockfilldam, results of all previous investigations were reviewed by WAPCOS and a needwas felt to drill few more boreholes along the dam axis DD. WAPCOS drilled sevenmore bore holes along the dam axis in the latest exploration program, with totallength of drilling 581m at the dam axis D-D.

1.9.2 Reasons for selection of rockfill dam

The reasons in favour of the rockfill dam at Pancheshwar have been dealt in theearlier project reports of 1995 and 2003 in detail; which are summarized as under:

1.9.2.1 Geological Consideration

In view of the geological conditions, the rockfill dam was a preferred choiceconsidering the very high stresses which are likely to be developed for a highconcrete dam on broken and heterogeneous granitised quartzite rock mass withshears and weathered schist band. Further, extensive treatment of the foundationwill be required in case of concrete dam to strengthen the rock mass involving extracost. In case of rockfill dam, advantage has been taken by providing partial cutofftrench in the de-stressed portion of the right flank which reduces the excavationsinvolved. However, construction of Chute spillway on the left bank will requireextensive slope stabilization measures. Extra provision of cost may also be kept fortreatment of slide zone near the upstream toe on left flank of rockfill dam.



1.9.2.2 Seismic Consideration

The project area falls in zone-V of Seismic Zoning Map of India (IS: 1893, 2002).The region has been rocked by several damaging earthquakes. The rocks of highgrade complex Central Crystalline is bound by Martoli Thrust in north and MCT insouth. Similarly another high grade complex, Almora crystalline, is delineated oneither side by North Almora Thrust and South Almora Thrust. The high gradecomplex is separated from Tertiary Group of rocks by MBT. The tertiary group isdelineated in southern portion by the MFT or Himalayan Frontal Fault which hassurface manifestations at places. Neotectonic activities have been reported alongKarakoram Fault, ISZ, MBT and MFT. Recently fresh exercises on seismic analysisand evaluation of site specific seismic parameters were taken by CWPRS, Pune withupdated robust data base covering period up to 2015; and the recommendations aregiven as below.

The horizontal seismic coefficient of a 0.24 g and the vertical seismic coefficient0.16g are recommended for pseudo-dynamic design analysis for Pancheshwar Multi-Purpose Project for rockfill type of dam. In view of high seismicity of the project site,the rockfill dam is preferred over concrete dam from safety considerations. Therockfill dam has the inherent quality of earthquake shock absorption because of itsdamping characteristics and comparatively large time period.

1.9.2.3 Materials Consideration

Detailed investigations were carried out by CSMRS, New Delhi earlier to assess thesuitability and availability of various construction materials viz. Core, filter, rock fill,coarse and fine aggregates both on Indian and Nepalese sides. Based on the fieldand laboratory investigations, the total quantity of suitable construction materials foreach category was assessed. The quantity requirement for each of the constructionmaterial had been estimated on the basis of the drawings prepared during detaileddesign studies for the rockfill dam and found adequate. In the present study, theavailability of material for rockfill dam is reviewed and reassessed. The adequacyhas been established and the details are given in relevant sections.

1.9.3 Pancheshwar - General Layout and Project Components

1.9.3.1 General Layout

The present layout of Pancheshwar dam and power stations has been developedwith available topographic maps, updated topography and engineering geologicalinvestigations. The layout is given in the Drawing No. WAP/ PANCH/ ES - 06.

1.9.3.2 Diversion and Outlet Facilities

Overtopping of any partially constructed dam is very serious and may be disastrous.Therefore, embankment dams are mostly designed for a 100 year return periodflood. In the instant case, since the dam height is more than 300 m and the risk due



to overtopping will be much more, it was decided to adopt a higher than 100 yearreturn period flood. Based on the precedence of the Tehri Rockfill dam in India with aheight of 260.50 m, a diversion flood of 16,652 m3/s corresponding return period of 1in 1000 year, has been adopted for Pancheshwar Rockfill dam. Accordingly, thediversion facilities comprising of six diversion tunnels with a total length of 16753 m,have been provided in left and right abutments along with upstream and downstreamcofferdams.

1.9.3.3 Diversion Tunnels

Six diversion tunnels, each 14m dia, circular shaped are provided to pass thediversion flood. The length of each tunnel varies from 2504m to 3685m. The invertlevels at the inlet portals of tunnels are proposed at EI 410 m(+/-) to suit the riverlevel. The downstream portions of four tunnels are proposed to be utilized astailrace tunnels and the diameter proposed for such reaches to suit the tailracedischarge hydraulics.

1.9.3.4 Cofferdams

Based on the studies, the crest of the upstream coffer dam is proposed atEL461.0m which provides a freeboard of 1.5m for passing 1000 year flood. Duringmost of the construction period, with all the tunnels in operation, this crest levelwould provide significantly larger freeboard for floods of lower return period. Thecrest of the downstream cofferdam was selected at El 436.0 based on theavailable tail water rating curve. This crest level would provide a freeboard of about3.5 m above the level of the computed 1000 year maximum outflow.

1.9.3.5 Depletion Arrangements

The depletion arrangements provided in the earlier studies at EL 544m are designedfor a discharge of 580 cumec. With this depletion arrangement to deplete thereservoir upto EL 544.00m it takes 225 days. In the emergency situation thedepletion of even the top 20 m of the reservoir would take about 40 days. If a gatedstructure is provided with about 20 m high gates they can store 2 BCM of water,which is nearly one third of the live storage. By opening the gates the top 20 m canbe depleted in 2 to 3 days only. Accordingly two depletion arrangements by utilisingtwo diversion tunnels to function as depletion tunnels have been made one on eachbank has been provided at EL 540 m having a capacity of about 900 cumec each.The depletion tunnels will be connected to one of the diversion tunnels with a gooseneck arrangement. Since the head over the crest of depletion tunnels upto crest ofmain spillway is very high, during the detailed design stage one additional inlet at EL+ 600 m can be provided to deplete the reservoir from EL. +659m to 600 m and thenthrough the depletion sluice at EL +540 m.



1.9.3.6 Design of Rockfill Dam

The proposed arrangement includes a rockfill dam with crest at EI 691 m, a separategated side channel spillway on the left abutment, two identical undergroundpowerhouses located one in each abutment and two intermediate outlets located intunnels under the respective power intakes. The maximum height of the dam is 311m above the foundation. The crest of the dam is 20 m wide and approximately 814mlong. The dam axis has been located as far downstream as possible, into thenarrower portion of the valley, to minimize embankment volume. The downstreamtoe has been kept upstream of a deep gully dissecting the left abutment which will bepart of the spillway discharge area.

A rockfill dam with central earth core and thick filter transitions upstream anddownstream is a fundamentally safe structure at seismically active sites and isconsidered the most appropriate dam type for the Pancheshwar. A symmetrical,central impervious core is proposed with upstream and downstream slopes of 0.3:1.The central core has been preferred over the inclined core as it would rest almostentirely on competent quartz biotite gneiss. Due to the potentially high site seismicityand moderately weak rock available for Rockfill material, a 3.5:1 upstream slopeand a 2.0: 1 downstream slope have been adopted for the layout. The dam heighthas been provided with a total freeboard of 11 m above FRL.

1.9.3.7 Foundation Treatment of Pancheshwar dam

The dam foundation will be stripped of colluvium, talus and other loose deposits. Thefoundation for the core, two upstream filters and three downstream filters will beexcavated through the uppermost weathered rock to fresh, sound, groutable rock. Atdam crest level, the depth of rock excavation for the core foundation is anticipated tobe of the order of 30 to 50 m, decreasing to a few metres under the 20 m thickalluvial deposits in the river channel. Dental concrete will be used to fill alldepressions in the core foundation and to provide an even, non-erodible surfaceagainst which to place and compact the core material. Consolidation grouting hasbeen proposed 6 m c/c below full area of C.O.T. The depth of consolidation groutinghas been kept as 0.15 H (where H is the hydraulic head) subject to a minimum of 10m. Curtain grouting beneath the core foundation is proposed below C.O.T aftercompleting the consolidation grouting. The grout curtain shall consist of three rows at3m c/c. The spacing between Primary Holes shall be 6m and between secondaryholes 3m. The depth of Grout Curtain shall be 2/3 H where H is the water headsubject to a minimum of 10m.

1.9.3.8 Design of Pancheshwar Spillway

The side-channel spillway is located on the left abutment. In order to avoid thenecessity for large free-standing retaining walls adjacent to the dam core, thespillway has been placed completely in rock cut and independent of the dam. Thespillway facility comprises approach channel and side-channel spillway, Spillway



Chute and Flip bucket and Plunge pool. The concrete dam spillway structure havingheight of 63.0 m with a total length of 185.50m comprises of 122.5 m long Over flowand 63.0m long Non-Over flow sections on both the sides, with 650.0m longapproach channel on upstream has been provided on the left bank (Nepal side) ofriver Mahakali.

1.9.3.9 Intake and Pressure Tunnels

Due to rock fill character of the dam material, the intake is not located in thedam body and, hence the intake structure is proposed to be located inside thereservoir away from the dam body. Six circular steel lined pressure tunnels havinglengths varies from 1000m to 1230m are proposed on either bank for diverting thewater for power generation. The centre line of tunnel has been kept at EL 600.00at its start at intake.

1.9.3.10 Vertical Drop Shafts / Penstocks

Water from intake level at El. 600 m (centre line) has to be led to the centre line ofthe units at El. 411m. The diameter of the vertical drop / pressure shaft has beencalculated as 8.70 m. At the bottom of the shaft, the water conductor turns horizontaland each one is bifurcated to feed two machines. The entire shaft and the horizontalunit tunnels are to be steel lined. 24 to 40 mm thick ASTM 517 GR.-F steel lining isproposed. The excavated diameter of tunnel will be about 9.7 m.

1.9.3.11 Pancheshwar dam- Power Houses

The proposed underground power house will accommodate the Six units of 400 MWcapacity each. The power house opening will be located in quartzites / grainsizedschist. After giving due consideration to the size of openings required for housing thegenerating units, transformers etc. and the geology of the area, it is decided toadopt, a two cavern layout for the power house. The first cavern, designated as themachine hall cavern, accommodates the generating units and other ancillaryequipment etc. excluding the MIV, whereas the second cavern, designated as thetransformer hall cavern, on the downstream will house the unit transformers and theGI switches. The caverns are aimed to be so located as to be excavated in singlerock type and are oriented to produce minimum over breaks / rock falls. The size ofmachine hall cavity to house the vertical shaft Francis turbine has been proposed as23m x 57.3m x 286.5m. The MIV will be accommodated in other cavity. Thetransformer hall cavern will be 18.50 wide, 32m high and will also have a length of224m. Draft tube gates will be accommodated in this cavern.

1.9.3.12 Pancheshwar dam - Downstream Surge Galleries

Transient studies have been carried out and based on the study it is proposed toprovide a d/s surge gallery. The size of downstream surge gallery has beenproposed as 90m (L) X 20 m (W) X 60m (H) on both India and Nepal side.



1.9.3.13 Draft Tube Tunnels/Tail Race Tunnels at Pancheshwar

Independent circular elbow type draft tube tunnels have been provided for each unit.The invert level of the draft tube has been kept at El. 399.20m. The draft tubetunnels from 3 units combine into one tail race tunnel of 12.25m in dia. These two tailrace tunnels will then join the diversion tunnels proposed for the rockfill damconstruction. The diversion tunnel will be plugged at its junction point with tail racetunnel u/s of junction point.

1.9.4 Rupaligad Re-Regulating Dam

1.9.4.1 General Layout

As per the provisions in Mahakali treaty, the proposed power stations at thePancheshwar would be operated as peaking station to maximize power benefits tothe power system of India and Nepal. To even out the fluctuations in the releasesdue to peaking operation of the Pancheshwar power Stations, a downstream re-regulating dam with adequate storage capacity needs to be constructed to providecontinuous river flows downstream. A re-regulating structure at Rupaligad withadequate pondage has been agreed to for further investigations and included in thescope of the WAPCOS.

Based on the updated survey & investigations, a new dam site was selected d/s ofthe earlier site. The FRL for Rupaligad re-regulating dam has been adopted as 420mconsidering tail water level of Pancheshwar dam. In addition to topographical andgeological considerations, the dam axis is selected at the nearest possible locationfrom the Pancheshwar dam where it can provide a live storage of about 56.43 M m3

for at least 4 hr peaking corresponding to 4800 MW plants. Accordingly, the damaxis at 'B-B' has been finalized on the downstream of Rupaligad Nala consideringgeological and topographical aspects.

1.9.4.2 Rupaligad Concrete Gravity Dam

The Rupaligad dam intercepts a total catchment area of 13,490 km2 and envisagesconstruction of a concrete gravity type dam of 95 m high above the deepestfoundation level and 265 m long at the top of dam. The overall length of the non-overflow section of the dam is 73.50 m extending on both the flanks of the spillway.The overflow section of the dam is 192m long. The dam top has been kept atEL.428.00m.

The dam would provide a gross pondage of 81.25 Mm3 and live pondage of 56.43Mm3 between MDDL +400.00m and FRL +420.00m to enable the re-regulationenvisaged under the project.



The non-overflow section of the dam has the following features:

Deepest foundation level = EL 376.00 m Top width of the dam = 8.00 m Upstream Slope = 0.3 (H) : 1 (V) Downstream Slope = 0.8 (H) : 1 (V)

Given the height of the dam section, requisite numbers of drainage and inspectiongalleries have been provided. An elevator shaft has been provided in the left sidenon-overflow section in order to access the galleries. Stair Shafts have also beenprovided in the left and right side non-overflow sections.

The PMF at Rupaligad dam site has been estimated 27,700 m3/s and RiverMahakali, like other Himalayan rivers, carries a lot of sediment load during themonsoon period. At this stage of project planning, determining reservoir operatinglevels and spillway and intake sill levels becomes important as they have a directbearing on the sediment management in the reservoir, as well as on the possibleencroachment of live storage. Moreover, design of spillway itself has to be such thatboth flood control and sediment control are effectively assured.

It is desirable that the spillway is accommodated within the river valley in order tominimize excavation on the banks. At the project site, a provision of low level sluicespillways is adequately effective for flood and sediment management.

1.9.4.3 Rupaligad dam – Spillway and Energy Dissipation arrangement

To optimize the spillway crest level, several studies were conducted to pass the PMFof 27,700 m3/s; with varying crest level and number of spillway bays. The alternative,with crest level at EL 386.00m and 12 spillway bays each of 9.5 m (W) X 14.5m(H),and adjacent bays are separated by twin piers, each 6.5 m thick, has been finalizedas it fits suitably in the available valley width.. Discharging capacity of the spillwayhas been verified using the criterion given in IS-11223-1984, which stipulates anemergency condition such that 10% of the number of gates or at least one gateshould be considered inoperative while deciding the dimensions of spillwaywaterway. It is confirmed that the proposed spillway has a discharging capacity topass PMF of 27,700 m3/s through 11 gates with MWL at EL 424.0m.

Various alternatives for energy dissipation arrangements were also considered. Dueto high intensity of discharge, provision of a stilling basin was ruled out and a flip/trajectory bucket has been adopted. Hydraulic design of the flip bucket has beendone as the procedure given in IS 7365:1985. As per the IS code, bucket flip angle isnormally kept between 30˚ to 40˚. From Geological explorations at the dam site, bedrock is available at about 20 m below the river bed level; i.e. at EL 340.0m. Hence, apre-formed plunge pool, with bottom at EL 340.0m has been proposed.



1.9.4.4 Diversion Arrangements

The diversion tunnels at Rupaligad dam site have been designed to pass a designflood of 2000 m3/s only and aligned behind the powerhouses due to physicalconstraints. The tunnels are aligned such that sufficient covers to other structuresare available. A single tunnel having capacity to pass the entire diversion flood willeither have a large diameter or will require a higher driving head. The driving headwill increase height of the upstream coffer dam, increasing its quantities andprolonging its construction period. Therefore, it has been decided to have twodiversion tunnels each of 12 m diameter with circular shape, one each on eitherbank, each capable of passing a discharge of 1000 m3/s.

In order to provide comfortable working space for construction of main dam, theupstream coffer dam (Colcrete) is proposed to be located at a minimum cleardistance of 75 m from the anticipated edge of excavation for foundation of the maindam. The Colcrete dam has been selected as its downstream face shall be steppedto make it serve as energy dissipater during overtopping. The toe will be providedwith a launching apron for saving river bed from erosion during overtopping. Theheel will be provided with a concrete apron or pad for making grouting activityindependent of the construction of dam. Elevation of the deepest bed at the dam axisis anticipated at EL.361.00 m; and it has been adopted at the location of upstreamcoffer dam. Considering the elevation of the water pool at the cofferdam is 383.50 mand providing a free board of 1.5 m; top of the coffer dam has been kept at 385 m.The length of upstream coffer dam worked out as 163.00 m and height of the dam atthe deepest section is 24.00 m.

The downstream coffer dam is proposed to be located at a minimum clear distanceof 200m from the anticipated edge of excavation for foundation of the plunge pool. Arockfill dam section has been selected on the same lines as the upstream cofferdam. Elevation of the deepest bed at downstream is assumed at EL 360.00 m andthe same was adopted as the foundation level for d/s coffer dam. The top level ofdownstream coffer dam has been kept at EL. 377.00 m with a free board of 1.5 m.The length of Downstream Coffer Dam is 110.00m and Overall height of the dam atthe deepest section is 17.00 m.

1.9.4.5 Rupaligad dam - Power Intakes and Headrace Tunnels

Straight type intake structures having asymmetrical approach has been envisagedon the u/s of the Rupaligad Reregulating dam to divert the design discharge of300m3/s through water conductor system on each bank of the river Mahakali forgeneration of power. The power intake structure comprises of two independentintakes on either side of the river at a distance of around 90 m from the dam axis onefor each of the Head Race Tunnel (Steel Lined) connecting the power intake to thepower house. Each intake has been provided with a trash-rack structure at the u/sedge and gates and hoisting arrangements for closing or opening of the flow into theHead Race Tunnel (Steel Lined).



Two numbers 6.5m dia. steel lined HRT have been provided on each side of the riverbank to convey the design discharge from the power intake to the generating units.The HRT are steel lined up to the proposed underground powerhouse located d/s ofthe dam axis. The length of the four HRT (two on each side) varies from 284m to354m upto D-line of Power house.

1.9.4.6 Rupaligad dam - Power House Caverns

The general arrangement the powerhouse has been developed for the installation oftwo units of 60 MW each and two vertical axis Kaplan Turbines. The powerhouseCavern is 112m (L) X 24.0 m (W) X 49.5m (H) in size units are placed at 28 m c/c.About, 26 m long erection bay is located at the Left end, while the 24 m long controlblock is located at the right end of the machine hall cavern. The centerline of runneris set at El 353.55 m.

1.9.4.7 Rupaligad dam - Tail Race Tunnels

Two numbers tail race tunnels each of 7.00 m dia. for the left and the right bankpower houses have been envisaged to convey 150cumec each of design dischargefrom the generating units back to the River Mahakali. The length of tailrace tunnels isapprox. 89m for the right bank power house(Indian side) and 55m for the left bankpower house (Nepal side) respectively. The invert level of the tailrace tunnel at thestart EL 344.00 and at the outfall is 362.0m where the Min. tail water level isEL 363.0m.

1.10 Design of Electrical and Mechanical Works

1.10.1 Pancheshwar Power Stations

The Pancheshwar Power Houses are proposed to have a total installation of 4800MW with six units of 400 MW each on either side. The alternative units of 350MW, 400 MW and 540 MW were also considered. However, the unit size of 400MW was preferred considering the maximum permissible cavern width and transportlimitation of the Over Sized Cargo/ heaviest components. The salient parameters ofthe underground power stations are as under:

1. Size of MIV Caverns 192m x 10m x 24m (LxBxH)2. Power House Caverns size 286.5m x 23m x 57.30m (LxBxH)3. Transformer Hall Caverns size 254 x 18.5 x 31.50m (LxBxH)4. Size of the service Bay 60m x 23m5. Turbine Centre line Elevation 411.8 m6. Machine Hall/Transformer Hall EL 428.8m7. Type of Turbine Vertical Francis8. Rated Discharge 184 m

3/s

9. Rated Net head 235m



Provision for appropriate governing equipment, generator and excitation equipment,generator transformer, switching scheme, electrical auxiliaries, cooling system,ventilation system, fire protection system, internal communication system has alsobeen made. The heaviest assembly required to be lifted by EOT cranes isassembled rotor which is expected to weigh 800T. Two cranes each of 425/ 80/10T operating in tandem using a lifting beam will be provided.

1.10.2 Rupaligad Power Stations

The salient features of the Rupaligad power stations having two units of 60 MW eachon either bank are given as under:

Power House Caverns size 112 m x 24m x 49.5 m (LxBxH) Transformer Hall Caverns size 75 x 19 x 31m (L x B x H) Machine Hall/ Transformer Hall EL EL. 366 m Centre-Line of runner EL. 353.55 m Type of Turbine Vertical Kaplan type Rated Net head 44 m Rated Discharge 150 m3/s Speed 150 rpm

1.11 Transmission System of Pancheshwar MultipurposeProject

1.11.1 Evacuation System for Pancheswar Power Plants

The step-up generation voltage of the Pancheshwar power plants at the India andNepal side is envisaged to be made from 21 kV to 400 kV through GTs for powerevacuation. The bus configuration of the switchyard would be double main-busscheme with GIS technology.

A surface mounted pothead yard each close to underground power plants at Indianand Nepalese territories is proposed to be established and transmission lines forpower evacuation would take-off from thereon.

Presently, no 400kV AC transmission system and 400 kV EHV sub-stations areexisting in Nepal grid. By the time of commissioning of Pancheshwar MPP, it isexpected that Nepal would harness many other hydroelectric generation projects inthe western and eastern parts of their country. Accordingly, Attaria, Lamki, Butwal,etc. deem to be the prospective locations for creating major EHV AC pooling pointsfor various upcoming hydro projects, which would enable to supply power to variousload centres in Nepal and transfer surplus outside Nepal after meeting its loaddemand. Considering this, generation from Pancheswar in Nepal is proposed to bepooled at Attaria in western Nepal, about 120km from Pancheswar and thereon to apooling point at Bareilly in India through cross border interconnection across



Mahakali River. On the Indian side, generation from Pancheswar MPP will be pooledat the Moradabad sub-station in the northern region (NR) for supply to load centres.

In view of the above, following 400 kV transmission system for evacuation of powerfrom Pancheshwar has been proposed:

Pancheshwar MPP (Indian side) – Moradabad (tentative location in India)400kV 2 x double circuit ACSR Quad Moose conductor lines.

Pancheshwar MPP (Nepal side) – Attaria (tentative location in Nepal) 400kV2 x double circuit ACSR Quad Moose conductor lines.

Pancheshwar MPP (Indian side) – Pancheshwar MPP (Nepal side) 400kVdouble circuit with ACSR Quad Moose conductor line.

Attaria - Bareilly 400kV 2 x double circuit ACSR Quad Moose conductor lines. 4x125 MVAr Bus reactors at Pancheshwar (Nepal side) Switchyard. 4x125 MVAr Bus reactors at Pancheshwar (Indian side) Switchyard. 2x125 MVAr Bus reactors at Attaria 400kV. Provision of space for additional four 420 kV line reactors on Indian side at

Pancheswar switchyard/ pothead yard, one reactor at Pancheswar end ofeach circuit, depending on the actual length of the transmission line on theIndian side.

Due to high fault current at Pancheswar and limitation of 400 kV GIS equipmentcapacity, the 400kV Pancheswar (Indian side) - Pancheswar (Nepal side) doublecircuit inter-connection would be kept normally open and used in case of emergencysituation only.

1.11.2 Evacuation System for Rupaligad Power Plants

The generated power at Rupaligad is proposed to be stepped up from 11kV to 220kV using three phase GTs for evacuation through 220kV transmission system. Thepooling point for Rupaligad power plant in the Indian side is considered to be theexisting 220 kV Sitarganj (PG) sub- station in the Northern Region. In the Nepal side,the generated power is proposed to be pooled at Attaria; along with power generatedat Pancheswar on the Nepal side. The transmission systems for Rupaligad powerstations are envisaged as under:

220 kV double circuit line with ACSR Zebra conductor from Rupaligad powerplant (India side) to Sitraganj (PG) in the Northern Region of India.

220 kV double circuit line with ACSR Zebra conductor line from Rupaligadpower plant (Nepal side) to 400/220kV pooling station at Attaria in Nepal.

A 220 kV single circuit inter-connection, with ACSR zebra conductor, betweenthe power plants at Rupaligad.



1.12 Environmental and Socio-Economic Impact

The objective of Environmental and Socio Economic Impact Assessment study is toidentify the possible environmental effects due to the proposed PancheshwarMultipurpose Project and to suggest measures to mitigate the anticipated adverseimpact in the environment. This study in Indian portion has been carried out byWAPCOS whereas Water Resources Consultant Pvt. Ltd., Kathmandu has carriedout studies in the Nepal portion.

1.12.1 Flora & Fauna

The proposed project area supports good vegetation in the submergence area. Thevegetation may be divided into the following categories in India: tropical forest,subtropical forest, temperate forest, sub-alpine forest and alpine forest. Theclassification of vegetation in Nepal is subtropical hill sal forest, subtropical mixeddeciduous forest and subtropical chirpine forest. Chir forest is predominant in thecatchment mainly in the upper reaches of hills (1500 to 1800m). The secondpredominant species, Oak can be found in the upper reaches of hills (1800 -2700 m).Cedrus deodar is the most common species in the area and can be found in the hills(1350-2050 m). Sal, Sisso, Khair and Tansen are other species in the area.

This area is the home of a wide variety of mammals, reptiles and birds. This region isrich in mammalian fauna i.e. Sambhar, Barking deer, Wild bear, Jackal etc. Fauna ofthis region include many species of goats and hare and they are distributed all overhigher altitude ranges. Among the carnivores, the most beautiful is the snow leopard.The others include jackal, cats, brown and black bear. Himalayan monal pheasant,the western tragopan, the satyr tragopan, chir pheasants and kottars are the birdsfound here. In the Nepalese portion, weasel, jungle cat, wolf, rhesus monkey, langur,porcupine etc. are found. The Mahakali, Sarju, Panar and Ramganga harbour richestdiversity for any cold water river. The major groups found are trouts, mahseers,minor carps and leaches. They contribute significantly in meeting the foodrequirement of local inhabitants.

1.12.2 Rehabilitation & Resettlement

Of the 116 km2 submergence area of Pancheshwar dam, 76 km2 lies in India and therest in Nepal. It covers 123 revenue villages in Pithoragarh, Champawat and Almoradistricts and 25 Village Development Committees (VDCs) and one Municipality in thedistricts of Darchula and Baitadi in Nepal. A total of 29436 PAF on the Indian sideand 2786 PAF on the Nepalese side are likely to be affected by the Pancheshwardam reservoir. In addition, 1587 families in eleven villages of the district Champawatin Uttarakhand State are likely to be affected due to the Rupaligad dam.

On both sides, there are a number of temples and other religious places would getsubmerged in the reservoir area besides many installations for drinking water supplyschemes. These temples are important cultural heritage of the local people.



1.12.3 Environmental Management Plan including R & R Plans

An amount of INR 29,860 million has been provided in the estimate forEnvironmental Management Plan including rehabilitation and resettlement (R&R)plan of the project affected families (PAF) on both sides. In addition, INR 16,555million has been kept towards the compensation of private land on the Indian sideand INR 4000 Million on the Nepal side under Environmental Management Plan.

1.13 Construction and Equipment Planning

1.13.1 Basic Considerations

It is essential to optimize the construction cost vis-a-vis construction period takinginto consideration price escalation and interest during construction as well as lostbenefits due to delay in completion. Therefore, even sizeable increases in theconstruction cost of components dictating the critical path for the projectcommissioning would be justified should they allow a significant shortening of theconstruction period.

1.13.2 Access Road and Infrastructure

Due to its bi-national character, the project shall be accessible both from Nepal andIndia. Indian access being the most important from construction point of view, asmost of the material and equipment is likely to be delivered to the site from India.

Various roads proposed to be constructed in the project area would be in the form ofmetalled access roads, metalled service roads and gravelled haul roads. It isproposed to have main access to the project from Tanakpur; It has been proposedto improve the existing road from Bareilly to Pancheshwar for transporting heavyequipments. The improved road would be used for transportation of constructionmaterials and for general access road to the project site. It has therefore beenproposed to have separate access road for project area. Champawat-Kot-Ratapani-Dam site access road is found to be more suitable. The route proposed is the shorterand links most of the infrastructure facilities. It has better road geometry profile andpasses through less forest area.

Various infrastructure facilities, like office buildings, residences, stores, workshops,laboratories, hospital, schools, etc. would be provided near project site to ensuresmooth implementation, operation and maintenance of the project. Two majorresidential colonies at Chaunda and Nidil on India side and Palaki and Sontala onNepal side are proposed for the project personnel at Pancheshwar. At Rupaligadsite, it has been proposed to have residential complex for project officers and staff.Provision of land development has also been made for skilled and unskilledconstruction labour. The total land requirement is 150 ha for this purpose atPancheshwar and Rupaligad site.



1.13.3 Equipment Planning

Keeping in view that the volume of placement for the project is substantial,mechanised construction has been planned for all types of construction jobs so as toachieve consistent quality at a faster rate and also to minimise the requirement ofskilled manpower. Mechanisation requires a great degree of planning as regards tocost, production, work methods etc. Equipment planning has been done based onthe topography, geology, climate, sources of materials, access to project andinfrastructure facilities required. To avoid a large number of loading units and theirmatching hauling fleet required for the completion of the project, conveyor beltsystems are being contemplated to transport clay and shell material for rockfill dam.The selection of appropriate equipment, loading and hauling fleet and/ or conveyorssystem has been based on the hourly peak requirement and maximum size of theequipment available in India.

As most of the construction work is likely to be executed on contract basis, thetentative requirement of machines/ equipment has been worked out for analysis ofrates of work and for cost estimates. Though the contractors in all probability maysuggest their own construction techniques and equipment for the execution of the jobbased on the equipment actually available with him, the present exercise will help inevaluating the reasonableness of the bids and the construction methods within theoverall construction schedule and cost estimates.

1.13.4 Construction Programme

The construction programme has been drawn up to complete the Pancheshwarproject in 10 years and Rupaligad in five years.

1.14 Cost Estimates & Phasing of Expenditure

1.14.1 Abstract of Cost Estimates

The project cost for both Pancheshwar and Rupaligad dams and associated workshas been estimated at 2015 price level as under:

Sl.No.

Name of project component Estimated cost Remarks

1. Pancheshwar ₹294830 Million Annex-I2. Rupaligad ₹ 36,250 Million Annex-II3. Total cost ₹331080 Million

The cost of transmission system associated with Pancheshwar as well as Rupaligadhas not been included in the project cost. The power of Pancheshwar MultipurposeProject is going to be mainly fed into Northern grid of India after meeting the localrequirement of Nepal. The cost of entire power evacuation system for PancheshwarMultipurpose Project including Rupaligad will be considered under separate projectproposals.



Similarly, cost of infrastructure for developing additional irrigation in India andNepal has also not been included in the project cost. A substantial expenditure oninfrastructure for irrigation particularly in Nepal may have to be incurred to realizefull irrigation potential of the project.

The General Abstract of costs for Pancheshwar Multipurpose Project includingRupaligad Re-regulating dam are given in detail, in the Table-1.14.1 & 1.14.2respectively.

Table 1.14-1: Abstract of cost of Pancheshwar Dam (INR Million)

Minor Head

Detailed Head of Work CivilWorks

Electro-Mechani

calWorks

Total

DIRECT CHARGESI-WORKS

A-Preliminary 5100 3171 8271

B-Land 28530 28530C-Works including HM works 105657 105657J-Power Plant Civil Works 35133 35133K-Building 1880 1880M-Plantation 100 100O-Miscellaneous 7800 7800P-Maintenance during construction@1% of C,J,K,R 1450 1450

Q-Special T&P 520 520R-Communication 21100 21100S-Power Plant & Electrical System 48059 48059

X-Environment & Ecology 29860 29860Y-Losses on Stock @0.25% of C,J,K &R 340 340

Total of I-Works 237470 51230 288700

ESTABLISHMENT 10447 1762 12209III-TOOLS &PLANTS 45 215 260

IV-SUSPENSE 0 0V-RECEIPT &RECOVERIES (-) -7860 -7860

Total of Direct Charges 240102 53207 293309

Indirect Charges(a) Capitalized value of abatement ofland revenue @ 5% of cost ofCulturable land

203 275

(b) Audit & Account Charges 1187 131 1318

Total of Indirect Charges 1390 131 1521Total Cost (Direct charges + IndirectCharges)

241492 53338 294830



Table-1.14-2: Abstract of Cost of Rupaligad Dam

Amount ₹ Million

Minor Head

Detailed Head of Work CivilWorks

Electro-Mechani

calWorks

Total

DIRECT CHARGESI-WORKS

A-Preliminary 780 430 1210B-Land 2690 2690C-Works 11920 11920J-Power Plant Civil Works 8060 8060K-Building 505 505M-Plantation 50 50O-Miscellaneous 1560 1560P-Maintenance during construction@1% of C,J,K,R 235 235

Q-Special T&P 320 320R-Communication 2690 2690S-Power Plant & Electrical System 4262 4262X-Environment & Ecology 1980 1980Y-Losses on Stock @0.25% of C,J,K &R 60 60

Total of I-Works 30850 4692 35542ESTABLISHMENT 1410 276 1686III-TOOLS &PLANTS 15 19 34

IV-SUSPENSE 0 0V-RECEIPT &RECOVERIES (-) -1208 -1208

Total of Direct Charges 31067 4987 36054Indirect Charges

(a) Capitalised value of abatement of land revenue @ 5% ofcost of Culturable land

15 15

(b) Audit & Account Charges 154 12 166Total of Indirect Charges 169 12 181

Total Cost (Direct charges + Indirect Charges) 31235 4999 36234

Cost at April,2015 Price Level Say 36250



1.14.2 Phasing of Expenditure

The Pancheshwar Complex is programmed to be completed in 10 years timeperiod while Rupaligad Complex would be completed in 5 years time period. Thedisbursement schedules of project expenditure in respect of Pancheshwar andRupaligad Complexes have been prepared spreading the cost of individual projectcomponents along the implementation period according to construction programme.

The total capitalized cost of power component of the Pancheshwar MultipurposeProject amounting to INR 305748.81 Million (including IDC and FC) has beendistributed in ten years. In addition, cost of Irrigation component has been assessedas INR 66,255 Million at April 2015 price level. The annual funds to be arranged byIndia and Nepal have been indicated below, indicating the cost charged to powerand irrigation and the share of cost to be borne by India and Nepal.

Table 1.14-3: Yearly requirement of funds to both countries (in INR Million)

Year Cost of Irrigation(INR 66255.00 Million)

Cost of Power component Total YearlyExpenditure (million)Equity (20%) Amount of Debt (80%)

India

(67%)

Nepal

(33%)

India

(50%)

Nepal

(50%)

India

(50%)

Nepal

(50%)

India Nepal

1 887.82 437.28 2648.25 2648.25 3536.07 3085.53

2 1775.64 874.55 5296.50 5296.50 7072.14 6171.05

3 2663.46 1311.84 7944.75 7944.75 10608.21 9256.59

4 3551.28 1749.11 10593.00 10593.00 14144.28 12342.11

5 4439.10 2186.40 12638.11 12638.11 17077.27 14824.51

6 6658.65 3279.60 20219.05 20219.05 26877.70 23498.65

7 6658.65 3279.60 22213.84 22213.84 28872.49 25493.44

8 6658.65 3279.60 24369.81 24369.81 31028.46 27649.41

9 6658.65 3279.60 26699.98 26699.98 33358.63 29979.58

10 4439.10 2186.40 22899.39 22899.39 27338.49 25085.79

Total 44390.85 21864.15 26482.50 26482.50 129040.16 129040.16 199913.51 177386.81

This information has been used for economic evaluation of the project components.

1.15 Economic and Financial Evaluation

The cost of the Pancheshwar project has been apportioned between Power andIrrigation sector in proportion to the assessment of (i) power benefits and (ii)irrigation benefits along with flood control benefits in accordance with provisions ofthe Mahakali Treaty. The benefits are summarized in the Table 1.15-1 below:



Table 1.15-1: Assessment of Project Benefits

Sl.No.

Project Benefits India Nepal Total (INR)

1. Power Benefits 18325 Million 18325 Million 36650 Million2. Irrigation benefits 5505 Million 2870 Million 8375 Million3. Flood Control Benefits 740 Million 160 Million 900 Million

Total 24570 Million 21355Million 45925 Million

The irrigation benefits have been assessed based upon the existing and future waterrequirements of India and Nepal as already indicated in the Table 1.8 – 2.

From the above, the ratio of (i) power benefits to (ii) Irrigation + Flood ControlBenefits from the Project has been calculated = 36650 : 9275 = 80 : 20. Hence thecost of joint works related to Pancheshwar dam and reservoir has been divided inthe ratio of 80:20 to calculate the cost of power project.

Further, it may be mentioned that the re-regulating dam/ structure at Rupaligad hasbeen envisaged mainly for irrigation consideration where the releases fromPancheshwar power plants during peaking operation would be collected and re-regulated to provide continuous flows downstream to meet irrigation waterrequirement of existing command areas in India and Nepal. As such, the cost of re-regulating dam and its appurtenant works at Rupaligad has been charged 100% tothe irrigation component. As the power generation at Rupaligad dam is onlyincidental in nature, the cost of power facilities and power plants of Rupaligad hasonly been charged to the power project.

1.15.1 Cost chargeable to Irrigation and Flood Control Component

Based on the above, 20% of the cost of common works (joint works) related toPancheshwar dam and 100% of the cost of Rupaligad re-regulating dam and itsappurtenant works have been apportioned to the irrigation sector; which would be, inturn, shared by India and Nepal, in the ratio of irrigation and flood control benefitsaccrued to them (67% : 33%). The irrigation and flood control benefits are indicatedin the Table 1.15-1 above.

1.15.2 Cost chargeable to Power Component

The project cost of Pancheshwar dam complex chargeable to power componentincludes the cost of J-Power Plant Civil works, cost of S- Power Plant & ElectricalSystem and 80% of the cost of common works of Pancheshwar dam andappurtenant works. In case of Rupaligad dam complex, the project cost chargeableto power component includes only the cost of J-Power Plant Civil Works and S-Power Plant & Electrical System as shown in the Table 1.15-2 below:



Table 1.15-2: Apportionment of project cost in power and irrigationProject component Pancheshwar

(INR Million)Rupaligad

(INR Million)Total Cost

(INR Million)1. Cost of J-Power Plant Civil

works35,133 8,060 43,193

2. Cost of S- Power Plant &Electrical System

48,072 4,260 52,332

3. Cost of Joint works 211,625 23,930 235,5554. Cost of Joint works chargeable

to power @ 80% forPancheshwar (and Nil forRupaligad)

169,300 Nil 169,300

A. Project Cost chargeable topower component= {(1)+(2)+ (4)}

252505 12,320 264,825

B. Cost of Joint works chargeableto Irrigation component @ 20%for Pancheshwar + full cost ofRupaligad re-regulating dam

42,325 23,930 66,255

Total Estimated Cost 294830 36,250 331080

i. Cost of irrigation component of PMP = INR 66,255 Million (20.01 %).ii. Total cost of power project (Hard Cost) = INR 264,825 Million

The construction period of Pancheshwar project has been indicated 8 years inthe Mahakali Treaty. In addition, a period of 2 years will be required for pre-construction activities. As such, a total 10 years period has been considered inthe analysis. The year succeeding the year of commissioning has been taken asreference year (11th year after commencement of construction) for working outthe present value of cost. The hard cost of power project (INR 264,825 Million)has been spread over 10 years, as given in the Table 1.15-3 below.

Table 1.15-3: Phasing of Expenditure on power component of PMP

1st yr 2nd yr 3rd yr 4th yr 5th yr 6th yr 7th yr 8th yr 9th yr 10th yr

2% 4% 6% 8% 10% 15% 15% 15% 15% 10%

20% Equity

(from India & Nepal)

80% Debt

(raised from Financial Institutions)

5296.5 10593 15889.5 21186 26482.5 39723.75 39723.75 39723.75 39723.75 26482.5

Here, it may be mentioned that Interest during construction (IDC) on hard cost of thepower project and financing charges( FC) on the debt would be minimized if bothgovernments provide amount of equity upfront, say in the initial stage of construction,as mentioned in the aforesaid Table. In addition to IDC, 1% of loan amount hasbeen considered as financing charges on the loan amount.



1.15.3 Capitalized Cost of Hydropower Project

The capitalized cost of power component of Pancheshwar Multipurpose Project(after adding the Interest during construction (IDC) and Financing charges for loancomponent) has been estimated as INR 305,748.81 Million for proposed relaxednorms viz. rate of interest @ 10%, R o E @ 14 % and repayment period of loan as20 years. The cost of Irrigation component which has been estimated INR 66,255Million, has not been included in the aforesaid capitalized cost of the Project. Thiscost is based upon April 2015 price index without any escalation amount.

1.15.4 Levelized Tariff and Internal Rate of Return (IRR)

In order to recommend the best option for financing of the project, the LevelizedTariff of the project and IRR have been calculated for different loan repaymentperiods as shown below:

Table 1.15-4: Levelized Tariff and IRR for different loan repayment periods

Option Equity:Debt

Norms Repaymentperiod of

loan

InternalRate

Return(%age)

Levelized Tariff (in INR)90%

DependableEnergy year

Averageenergy

yearI 30;70 CERC 12 years* 14.65 7.96 6.11

II 20:80 CERC 12 years* 13.02 8.00 6.14

III 20:80 Modified 20 years 10.23 5.65 4.33

IV 20:80 Modified 25 years 10.24 5.66 4.34

V 20:80 Modified 30 years 10.25 5.66 4.35

VI 20:80 Modified 35 years 10.25 5.67 4.35

* Assuming 90% loan would be returned in 12 years.

1.16 International and Interstate Aspects

During the prolonged negotiations held on the Pancheshwar project, Nepal hasasked India to recognize that both parties have equal entitlement in the utilization ofthe waters of the Mahakali River. The Indian side agreed to their entitlement underthe Mahakali Treaty-1996, without prejudice to their respective consumptive uses ofthe waters of the Mahakali River.

An understanding was reached between the two sides finally in the year 1996 whenthe Mahakali Treaty was signed on February 12, 1996 between the Government ofIndia and the Government of Nepal concerning the integrated development of theMahakali River.

The main features of the Mahakali Treaty-1996 in respect of the PancheshwarProject are covered in the Article-3 and summarized as under:



Both Parties have equal entitlement in the utilization of the waters of theMahakali River without prejudice to their respective existing consumptiveuses of the waters of the Mahakali River.

Water requirements of Nepal shall be given prime consideration in utilizationof the waters of the Mahakali River. Both the parties shall be entitled to drawtheir share of waters of the Mahakali River from the Tanakpur Barrageand/or other mutually agreed points.

The Project shall be designed to produce the maximum total net benefit.All benefits accruing to both the Parties with the development of the Projectin the forms of power, irrigation, flood control etc., shall be assessed.

The P roject shall be implemented as an integrated project includingpower stations of equal capacity on each side of the Mahakali River andthe total energy generated shall be shared equally between the Parties.

The cost of the project shall be borne by the parties in proportion to thebenefits accruing to them.

Both the Parties shall jointly endeavour to mobilize the finance required forthe implementation of the Project.

A portion of Nepal’s share of energy shall be sold to India. Thequantum of such energy and its price shall be mutually agreed uponbetween the Parties.

The principles for assessment of project benefits are explained further inthe letters dated 12 February, 1996 exchanged by the two Governmentsalong with the Mahakali Treaty, as under:

Net power benefit shall be assessed on the basis of, inter alia,saving in costs to the beneficiaries as compared with the relevantalternatives available,

Irrigation benefit shall be assessed on the basis of incrementaland additional benefits due to augmentation of river flow, and

Flood control benefit shall be assessed on the basis of the valueof works saved and damaged avoided (to both sides of the river).

1.16.1 Irrigation Benefits

The waters of Mahakali River are being utilized for irrigation in India since thecommissioning of Banbasa Barrage in 1928. Some Terai area in Nepal has alsobeen benefited by the Mahakali waters drawn from the Banbasa Barrage.

With the availability of augmented flows in the post-Pancheshwar scenario, it hasbeen assessed that a maximum crop area of 170,720 ha (including 6,040 ha ofDodhara-Chandani area) in Nepal can be brought under irrigation with the availabilityof additional water on implementation of Pancheshwar Multipurpose Project. Fordevelopment of this command, additional water requirement will be of the order of



3,073 M m3. Total water use by Nepal will be 4,053 M m3 comprising of 980 M m3 asexisting use and 3,073 M m3 as future use.

Irrigation benefits in India have been assessed on the basis of evaluation of surplusaugmented flows available during dry season after meeting requirement for existingirrigation in India and Nepal as well as additional irrigation in Nepal. Havingconsidered the power releases from Pancheshwar and water available in theintervening catchment from Pancheshwar to the Tanakpur Barrage, India will be ableto make use of 1,905 M m3 of additional water in the post-Pancheshwar scenarioand annual irrigation potential in India works out as 2.59 lakh Ha. Thus, total wateruse of India will be of the order of 13,766 M m3.

The detailed statement of total water requirement of India and Nepal including RiverEco-system below Banbasa barrage is already indicated in the Table 1.8 – 2.

1.16.2 Power Benefits

As mentioned in the preceding paragraphs, the power plants at Pancheshwar damare designed as the peaking stations having a total installed capacity of 4800 MWwhich would generate 7678 GWh of power during peaking hours, say around 4hours a day in non-monsoon period in the 90% dependable year. In addition, thepower stations at Rupaligad would generate another 1438 GWh power as base loadstations in 90% dependable year. The total power produced at Pancheshwar +Rupaligad dam power plants shall be shared equally between India and Nepal as perthe Mahakali Treaty. The total energy generation in the 90% dependable year aswell as in average year from Pancheshwar Project are shown in the Table 1.16-1below:

Table 1.16-1: Various parameters of Project

Sl. No. Particulars Pancheshwardam

Rupaligaddam

Total

1. Installed Capacity (MW) 4800 240 50402. 90% dependable annual

generation (GWh)7678 1438 9116

3. Annual Load Factor (%) 18.26% 68.42% 20.65%4. Hours of peaking during Lean

Season03.84 Base Load

5. Average Annual Generation (GWh) 10327 1559 11885

1.16.3 Inter-state Agreements

As explained in the preceding paragraphs, at present, no agreement exists onsharing of the Mahakali Waters between party States or with neighbouring countries,except the Treaty referred above. If required, a formal agreement on sharing of the



Mahakali waters may be put up before the Party States for consideration by thePDA, while implementing the Project.

1.16.4 Interstate Aspects of the Project

It may be mentioned that, when the Pancheshwar dam site was surveyed andformulated initially by the State Irrigation Department, the project area on the Indianside was administered by the undivided State of Uttar Pradesh. Later on, in the year2000, the province of Uttar Pradesh was divided in two States and the main damproject area has been transferred to the newly formed State of Uttrakhand in India.The issue of sharing of irrigation assets / water resource between Uttrakhand andUttar Pradesh is yet to be settled.

1.16.5 International Aspects of the Project

Besides the Mahakali Treaty with Nepal, the Government of India had also enteredinto another Treaty (known as the Ganga Treaty) in 1996 with the Government ofBangladesh on sharing of the Ganges waters during dry season (1 January- 31 May)at Farakka barrage. As such, any water resource development project proposed inthe Ganga basin is required to seek a no objection from the Union Ministry of WaterResources, River Development and Ganga Rejuvenation, to ensure that theproposed scheme has no adverse effect on the lean season inflows at FarakkaBarrage.

It may be mentioned here that the river Ganga drains an area of 8,61,452 sq. kmalong its length (2525 km) up to its outfall in Bay of Bengal. Its water resourcespotential has been estimated as 525.02 Billion Cubic Meter out of which 250 BCM isconsidered utilizable by creating suitable storage schemes in the upper reaches ofthe river. At present, the live storage capacity created by India is around 60 BCMincluding the projects under construction.

The Pancheshwar dam project shall intercept an area of 12,276 sq km and averageannual flow at Pancheshwar dam site has been estimated 18.35 BCM. A total of11.90 BCM of the Mahakali waters are already utilized annually by the StateGovernments in India in the existing irrigation projects whereas 0.98 BCM of water isutilized by Nepal. Rest of the Mahakali waters pass as floods which is aimed to bestored in the Pancheshwar reservoir.

After implementation of the Pancheshwar Project, the Nepal side may utilize around3.07 BCM as additional water in the irrigation in their territory and 1.90 BCM of waterwould be available to the Indian side to increase the irrigation.

The Pancheshwar dam project has been primarily envisaged to store flood watersduring monsoon that would be utilized for energy production and to enhance foodgrains production through assured irrigation. Thus, the dam project would not haveany adverse impact on the lean season flows at Farakka. The catchment area



(12,276 sq km) at dam site is less than 1.5% of the total basin area at Farakkabarrage.

1.16.6 Dispute Resolution Mechanism

Under Article-7 of the Mahakali Treaty, both sides have agreed not to use or obstructor divert the waters of the Mahakali River adversely affecting its natural flow andlevel except by an agreement between the concerned parties. In order to meet thewater requirement of local communities living along both sides of the Mahakali River,they are provided right to use the Mahakali waters limiting to the five percent of theaverage annual flow at Pancheshwar.

Further, under Article-9 of the Treaty, there shall be a Mahakali River Commission todeal with the disputes arising out of interpretation of the provisions made in theMahakali Treaty. The Commission shall be guided by the principles of equality,mutual benefit and no harm to either party. The Commission shall be composed ofequal number of representatives from both the parties.

The functions of the Commission shall, inter-alia include the following:

a. To seek information on and, if necessary, inspect all structures included in theTreaty and make recommendation to both the Governments to take stepswhich shall be necessary to implement the provisions of this Treaty.

b. To make recommendations to both the Governments for the conservation andutilization of the Mahakali River as envisaged and provide for in the Treaty.

c. To provide expert evaluation of projects and recommendations thereto.d. To co-ordinate and monitor plans of actions arising out of the implementation

of the Treaty; ande. To examine any differences arising between the Parties concerning the

interpretation and application of the Treaty.

1.16.7 Power Purchase Agreements

Pancheshwar Project shall be implemented as an integrated project including powerstations of equal capacity on each side of the Mahakali River and the total energygenerated therein shall be shared equally between the two parties. However, anysurplus power from the Nepal share shall be purchased by India on mutually agreedrates. This would require the long term power purchase agreements with powerdistribution companies/ entities in India and Nepal.

The Pancheshwar Development Authority (PDA) shall act as power producingcompany/ entity and may be allowed to enter into such agreements with purchaserson behalf of both Parties.



1.17 Project Management and Design Engineering Consultancy

The Pancheshwar Development Authority (PDA) may consider the engagement of areputed agency/ consultancy firm as “Consultant” to undertake the projectmanagement during construction through competitive bidding. The consultancy firmmay assist and advise the Authority in preparation of bid documents and evaluationof bids. During the construction, the agency would be responsible and providerequisite expert manpower at site for general supervision of works in accordancewith technical specifications, inspection of materials at manufacture’s workplacesbefore despatch, monitoring of progress of works at site, preparation of completiondrawings, etc.

The Consultant shall specify in his technical proposal to the Authority, approach andmethodology to carry out his duties and for providing services towards planning,engineering, design, supervision and monitoring of progress of works at site onbehalf of the Authority.

After award of the contracts, the Consultant would prepare a detailed program basedon the reviewed and accepted programs of different Contractors and also the likelyinterfaces and activities with regard to the project execution at different levels. State-of-the art software will be used to prepare such schedules which will primarily includeearly starts and finishes, late starts and finishes, free and total floats, bar charts andimportant information like shut down, vacation etc. These schedules will form thebase line programme for monitoring the execution of the project. During the courseof the construction, this program will be reviewed periodically and updated taking intoaccount the site conditions and requirements. Similarly, in consideration of thepresent practices, requirement of equipment, plant and machinery will be assessedto reduce the construction cost and the time too.

The Consultant, in consultation with Authority, will monitor and supervise model testsof the turbines and other equipment carried out by the Manufacturer/ Contractor athis workplace to ensure that the prototypes shall meet the requirements andspecifications under the contract.

1.18 Conclusions and Recommendations

The Detailed Project Report can be summarized as follows:

The field investigations carried out and basic data available so far aresufficient to support the present design level and to confirm the technicalfeasibility of Pancheshwar Multipurpose Project. Some additional fieldinvestigations and studies may be required in pre-construction stage todevelop the final design of the project.

The optimum layout for the main Pancheshwar dam with power plants of 4800MW is based on a maximum normal reservoir level of 680 m a.s.l. and on a



rockfill type of dam. The project included a downstream re-regulating damwith 240 MW power stations, to assure a continuous flow to the irrigation inthe downstream.

As presently conceived, the project can be implemented and fullycommissioned in a 10 year period, starting from the moment a firm decision atthe political level is taken.

The cost of the entire bi-national infrastructure at 2015 price level is estimatedto be in the order of INR 33,108 Crore, excluding import duties and taxes.

The environmental impact of the project is manageable. Sufficient provisionhas been made for EMP as well as detailed resettlement plans for PAF.

The project will generate 9116 GWh dependable energy per year. It will meetthe water demand for existing and committed irrigation systems in India. It willalso provide water to irrigate 93,000 ha command area in Nepal.

The economic and financial indicators are sufficient to attract private capitalfor the development of the scheme, provided a firm economic and legalframework is established.

The Detailed Project Report is considered a suitable basis to startnegotiations for financial closure of the project.

In the mean time, on-going field activities, particularly the recording andmeasurement of hydrological, meteorological and micro-seismic data, shouldcontinue.



Annex-ISalient Features of Pancheshwar Multipurpose Project

Pancheshwar Dam (12 x 400 MW = 4800 MW)

A. LOCATION

1. Country India and NepalChampawat / UttrakhandBaitadi / Nepal

2. River Mahakali

3. Main Pancheshwar dam Near Pancheshwar Temple

Longitude L/B, Nepal 80o 15’ 5”

R/B, India 80o 14’41”

Latitude L/B, Nepal 29o 25’ 40”

R/B, India 29o25’53”

4. Re-Regulating dam at Rupaligad 27 km downstream of Pancheshwar dam

Longitude L/B, Nepal 80o 12’ 6.15”

R/B, India 80o 12’ 14.63”

Latitude L/B, Nepal 29o 07’ 38.81”

R/B, India 29o 07’ 55.78”

B. HYDROLOGY

1. Drainage area of the river atPancheshwar dam Site

12,276 km2

9861 km2 (India)2415 km2 (Nepal)

2. Average Annual Rain fall 1996.5 mm ( 1962-2012)

3. Average Annual Yield 582 m3/s (Pancheshwar)

4. 75% Dependable Annual Discharge 16128 Mm3 (Pancheshwar)

5. Probable Maximum Flood (PMF) 23,500 m3/s (Pancheshwar)

6. Design Flood for diversion(1000-year return period)

16,652 m3/s (Pancheshwar)

7. Annual sediment Load 58.18 Mm3/year

C. PANCHESHWAR DAM

1. Main Dam Rock fill with clay core

a. River bed level E.L. 410.00 m

b. Deepest Foundation Level E.L. 380.00 m

c. Top of dam E.L. 691.00 m

d. Height of dam 311.00 m

e. Length of dam at top 814.00 m



f. Upstream slope 3.5 (H):1 (V)

g. Downstream slope 2 (H) : 1 (V)

h. Top Width 20.00 m

i. Full Reservoir Level E.L. 680.00 m

2. Coffer Dams

a. Type Rockfill

b. Crest level of upstream Coffer dam 461.00 m

c. Crest of downstream Coffer dam 436.00 m

d. Height of U/S Coffer dam 81 m from Bed Rock

e. Height of D/S Coffer dam 56 m from Bed Rock

3. Spillway

a. Type Gated Chute

b. Crest length 185.5 m

c. Crest level E.L. 658 m

d. Invert level of Plunge Pool E.L.347.00 m

e. Energy Dissipater Trajectory Bucket Type

4. Diversion Tunnels

a. Numbers Six (3 on each side)

b. Diameter & Shape 14 m, Circular

c. Inlet level 410.00 m

d. Outlet level 397.00 m

5. Main Reservoir

a. Full Reservoir Level 680.00 m

b. Minimum Draw Down Level 615.00 m

c. Dead Storage 5317 Mm3

d. Submergence area of Pancheshwarreservoir

116 Km2 (Total)76 Km2 (India)40 Km2 (Nepal)

e. Gross capacity 11355 Mm3

f. Live Storage 6038 Mm3

g. New Zero Elevation after 100 year El. 511 m

h. Submergence due to Pancheshwardam

Villages 123 villages (In Pithoragarh, Almora&Champawat Districts of India)25 VDCs and one Municipality inDarchula & Baitadi Districts in Nepal

6. Power Intake



a. Numbers Six ( 3 on each bank)

b. No. of gates 12 (Service gate) + 12 (Emergency Gate)

c. Size 7.2 m (W) x 8.7 m (H)

d. Invert level EL. 587.40 m

e. Center line of intake EL. 600.0 m

7. Down Stream Surge Galleries

a. Numbers Four (2 nos. on each side)

b. Size 90 m (L) X 20 m( W) X 60 m (H)

8. Pressure Tunnels (Vertical +Horizontal)

a. Number Six (3 nos. on each side)

b. Type Steel Lined

c. Finished Diameter 8.70 m

d. Invert level at inlet EL 596.00.m

e. Design Discharge 368 m3/s of each tunnel

9. Power Houses

a. Number & Type Two (one on each side), Underground

b. Size 290 m (L) x 23 m (W) x 59 m (H) oneach bank

c. Installed capacity 12 x 400 MW

d. Transformer cavern 224 m (L) x18.5 m (W) x32 m (H) oneach bank

e. No. of Vertical drop shafts Six (3 on each side)

Diameter 8.70 m

Height 188.2 m each

f. Maximum Tail Water Level (at PMF) El. 435.00 m

g. Normal Tail Water Level El.420.70 m

h. Minimum Tail Water Level El.419.30 m

10. Tail Race Tunnels

a. Numbers, Diameter & Type Four – two on each side; of dia10m,Circular

b. Invert level at outlet EL 397.00 m

11. Draft Tube Tunnels

a. Numbers, Diameter & Type 12 (six on each side) of dia 7.00 m,Circular Elbow

b. Invert Level EL 402.00 m

12. Main Generating Plant



12.1 Turbines

a. Type of turbines Francis

b. Rated Output 406 MW

c. Net rated / design head 235 m

d. Synchronous speed 166.67 rpm

e. Efficiency at Rated head & output 94.5 %

f. Specific speed 134.5 m-kW

g. Design discharge 184 m3/s

h. Normal / Min. TWL EL. 420.7 m / 419.3 m

i. Type of Draft tube Cylindrical

12.2 Main Inlet Valves

a. No.& Type of valve Six- Bi-plane Butterfly on each side

b. Diameter 5.00 m

c. Design head 375 m

d. Max. operating flow 184 m3/s

13. Generator

a. No. & Type Six - Semi-umbrella on each side

b. Rated Output 400 MW

c. Max. output 440 MW

d. Short circuit ratio 1.1

e. Terminal Voltage 21 KV

f. Power Factor 0.85

g. Efficiency at Rated full load 98.5 %

h. Stator Diameter 9.68 m

i. Stator Height 8.60 m

j. Rotor Diameter 7.80 m

k. Rotor weight 763 T

l. Generator F.P. System Water

13.1. Isolated Phase Bus Duct

a. Rating 24/16000 kV/Amp.

b. Generator Circuit breaker rating Not provided

14. H.V. Equipment

14.1 Generator Transformers

a. No. & Type 40, 1-Phase

b. Rated capacity 519 (3x173) MVA

c. Cooling ODWF/OFWF



14.2 H.V. Switchgears

a. Type SF6 GIS Double bus bar

b. Voltage Rating 400 KV

c. No. of GIS bays 11 on each bank

14.3 H.V. Cables /GITL

a. Means of power evacuation GITL

b. No. of Circuits, voltage rating 3, 400 KV

14.4 Reactor

a. No. & Type 2 nos., 3-phase

b. Capacity & Voltage rating 80 MVAr, 400 KV

15 Mechanical Aux. Systems

15.1 EOT Cranes

a. Nos. & capacity of cranes for PH 2 no. of 400 / 80/10 T on each bank

b. Span 21 m

c. Nos. & capacity of cranes for MIVcavern

1 no.,150 T on each bank

15.2 Lifts

a. No. & capacity of lifts in P.H. & Tr.Hall caverns

5 nos. of 10 persons capacity each

16. Power Benefitsa. Pancheshwar Power Plant

i. Firm Power 767.27 MW

ii. Load Factor 18.26%

iii. Annual Generation (90%dependable year)

7678 GWh

b. Rupaligad Power Plant

i. Firm Power 133.80 MW

ii. Load Factor 68.42 %

iii. Annual Generation (90%dependable)

1438 GWh

17. Estimated Cost of the Project(2015 price Level)

a. Pancheshwar dam

i. Civil Works INR 241,492 Million

ii. E-M Works INR 53,338 Million

iii. Total Cost INR 294830 Million

b. Rupaligad

i. Civil Works INR 31,250 Million



ii. E-M Works INR 5,000 Million

iii. Total Cost INR 36,250 Million

c. Combined

i. Total Cost INR 331,080 Million

ii. Cost Chargeable to Power INR 264,825 Million

iii. Cost Chargeable to Irrigation INR 66,225 Million



Annex-II

Rupaligad Re-regulating Dam (4 x 60 MW = 240MW)A. LOCATION

a. Countries India and Nepalb. Districts Champawat, Uttrakhand, India, Baitadi,

Nepalc. River Mahakalid. Dam Axis 1070 m downstream of Rupaligad Nalla

confluencee. Power House Two nos. powerhouse – one on each bankf. Rupaligad Dam Longitude, L/B 800 18' 25.07'' (Nepal)

R/B 800 18' 15.75'' (India)Latitude, L/B 290 16' 55.761'' (Nepal)

R/B 290 16' 55.711'' (India)B. HYDROLOGY

a. Catchment area up to Dam site 13,490 km2

b. Average annual rainfall 1938 mmc. Average Annual Discharge 618.60 m3/sd. Probable Maximum Flood(PMF) 27700 m3/se. Annual Sediment Load 5.83 Mm3 (95% Trap Efficiency at

Pancheshwar)C. RUPALIGAD RESERVOIR

a. Full Reservoir Level (FRL) EL 420.00 mb. Minimum Draw Down Level (MDDL) EL 400.00 mc. Submergence Area 396.00 Ha.d. Gross Capacity 81.25 Mm3

e. Live Storage 56.45 Mm3

f. Dead Storage 24.80 Mm3

g. Maximum Water Level (MWL) EL 424.00 mD. RE-REGULATING DAM

a. Type Concrete Gravity damb. Average river bed level EL 361.00 mc. Deepest foundation level EL 333.00 md. Crest Level (Top of the Dam) EL 428.00 me. Height of Dam 95 mf. Length of Dam at top 265 mg. Width of Dam at top 8.00 m

E. SPILLWAYa. Type Sluice Spillway with Bucket Trajectoryb. Length of spillway portion (Overflow) 192.00 mc. Crest Gates 12 Nos Radial of 9.50 m (W) x 14.50 m (H)

eachd. Design Discharge 27700 m3/sece. Crest level EL 386.00mf. Full Reservoir Level EL 420.00 m



F. INTAKE STRUCTURESa. Type Bell Mouthb. No. Of Intake 4 No. (2 on each bank)c. No. Of Openings 8 No. (4 on each bank)

(2 openings converge into one HRT)d. No. of Gates 8 No. (4 on each bank)e. Size of Opening 3.0 m (H) X 5.53 m (W)f. Centre Line of Intake EL 392.00 mg. Invert Level of Intake EL390.50 m

G. DIVERSION TUNNELSa. Number Two no.(1 on each bank)b. Design flood for Diversion 2000 m3/s (1000 m3/s on each side)c. Shape and size Circular, 12.00md. Invert Level at Inlet EL.366.00me. Invert Level at outlet EL.361.00m

H. COFFER DAMSUpstream Coffer Dam

a. Type Colcreteb. Top Width 6 mc. Top Level EL.385.00md. Foundation Level EL.361.00 me. Height 24 mf. Length at top 163 mDownstream Coffer dam

a. Type Rockfillb. Top Width 7 mc. Top Level EL.377.00md. Foundation Level EL.360.00me. Height 17 mf. Length at top 110 m

I. HRT (Steel Lined)a. No. of HRT 4 No. (2 on each side)b. Design Discharge 150.00m3/s eachc. Shape and size Circular, 6.5 m dia.d. Centre Line of HRT at Intake EL392.00me. Invert Level at Inlet EL 390.50m

J. POWER HOUSE CAVERNSa. No. and Type Two nos.(1 on each bank), Undergroundb. Size 24.00 m (W) x 49.50 m (H) x 112.00 m (L)c. Service Bay Level EL 366.00 md. Type of Draft Tube gate Bonneted typee. Size of Draft Tube Gate 7 m (H) X 6 (W)

K. TRANSFORMER CUM GIS HALL CAVERNa. Type Undergroundb. Size 19.00 m (W) X 31.00 m (H) X 75.00 m(L)



L. GENERATING EQUIPMENTa. Type of turbine Kaplanb. No. of Turbines Four ( Two on Each Side)c. Unit Spacing 28.00 md. Net rated / design head 44.00 me. Rated Output 60 MWf. Synchronous speed 150 rpmg. Max. / Min net head 50.70m / 30.70 mh. Runner throat diameter 4.80 mi. Efficiency at Rated head & output 95 %j. Normal Operating / Min. TWL 367.00m/ 363.00mk. Design discharge 150 m3/sec.MAIN INLET VALVEa. No.& Type of valve Two nos., Bi-plane butterflyb. Diameter 5.5 mGENERATORSa. No. & Type Four (Two nos. on each bank), Semi-umbrella typeb. Rated Output 60 MW/ 71 MVAc. Max. output 66 MW/ 78 MVAd. Terminal Voltage 11 kVe. Power Factor 0.85f. Efficiency at Rated full load 98.5 %TRANSFORMER CUM GISa. No. & Type of Transformer 2 nos., 3 Fb. Rated capacity 78 MVAc. Voltage Ratio 11/220 kV

M. TAIL RACE TUNNELa. Design Discharge 150.00m3/s eachb. Numbers Four nos. (2 on each bank)c. Size and Shape 7.0m dia, Circulard. Invert Level at outlet Portal EL 362.0m

N. POTHEAD YARDa. Area 85m X 32.5mb. Elevation EL 420.00m

O. CABLE TUNNELa. Type Undergroundb. Size and Shape 6.5 m X 6.5 m, D-shaped

P. ENERGY GENERATIONa. Installed Capacity & Type 240 MW, Base Loadb. Annual Generation 1438 GWhc. Annual Load Factor 68.42 %

Q. ESTIMATED COSTCivil Works INR 31,250 MillionE & M Works INR 5,000 MillionTotal INR 36,250 Million (Say)



Table 1.8 - 2: Total Water Requirement of India and Nepal including River Eco-System (in m3/s)

Month WaterUtilization by

the LocalCommunitypermitted

fromMahakali

River

Existing Irrigation uses of India Water Requirement of Nepal Total Water demand to be protected

Existing irrigationuses of Saradacanal system at

BanbasaBarrage( for

round the year)

Existing Irrigation atLower Sarada Barrage

(Sarada Sahayaksystem) during

Monsoon Season

(16th June - 15th Oct.)

TotalExistingIrrigation

uses of India

Existing Irrigationrequirement of

Nepal at BanbasaBarrage and

Tanakpur Barragefor round the year

Future Irrigationrequirement of

Nepal for 93000 haincluding

requirement ofDodhara Chandani

area @ 10 m3/s

TotalIrrigation

Requirementof Nepal

CompulsoryDownstreamreleases for

maintaining Rivereco-system belowBanbasa Barrage

Gross WaterRequirement forIndia and Nepal

(5)+(8)+(9)

Additional wateravailable toIndia during

Rabi season forIrrigationbenefits

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11)June 29.15 283.90 135.30 419.20 56.70 39.20 95.90 0.00 515.10 -July 29.15 296.70 650.00 946.70 56.70 160.60 217.30 0.00 1164.00 -Aug. 29.15 294.00 174.00 468.00 56.70 84.10 140.80 0.00 608.80 -Sept. 29.15 295.90 650.00 945.90 56.70 137.50 194.20 0.00 1140.10 -Oct. 29.15 280.80 213.30 494.10 34.90 175.20 210.10 0.00 704.20 -Nov. 29.15 217.20 0.00 217.20 12.75 20.55 33.30 10.00 260.50 134.46

Dec. 29.15 179.30 0.00 179.30 12.75 35.45 48.20 10.00 237.50 145.16Jan. 29.15 156.40 0.00 156.40 12.75 42.45 55.20 10.00 221.60 145.27Feb. 29.15 142.00 0.00 142.00 12.75 54.05 66.80 10.00 218.80 165.73

March 29.15 143.10 0.00 143.10 12.75 84.65 97.40 10.00 250.50 136.91Apr. 29.15 165.50 0.00 165.50 12.75 191.95 204.70 10.00 380.20 3.37May 29.15 236.00 0.00 236.00 34.90 143.80 178.70 10.00 424.70 -

Mean (m3/s) 29.15 224.23 151.88 376.12 31.09 97.46 128.55 5.83 510.50 121.82Volume

(in Million m3)920.00 7,071.00 4,790.00 11,861.00 980.00 3,073.00 4,053.00 184.00 16,100.00 1,905.00

Note:

1. Use of water permitted from Mahakali River by the Local Community, @ 5% of the annual average inflow at Pancheshwar, has been subtracted from the grosswater availability at Pancheshwar under the provision of Article-7 of Mahakali Treaty.

2. As per Article 1 (2) of the treaty, a flow of minimum 10 m3/s is to be maintained for River eco system below Banbasa Barrage. However, as the releases belowBanbasa Barrage to meet requirement of Sarada Sahayak system for the monsoon months from June to October are higher than the requirement of eco-system,no compulsory releases from Pancheshwar are considered for these months.

3. It is presumed that the augmented flows that may be available from Pancheshwar, after meeting the existing demands of India and existing and future demands ofNepal shall be utilized fully by India for additional irrigation.

Consultant:

76-C, Institutional Area, Sector – 18, Gurgaon – 122015, Haryana (INDIA)

Telephone: 0124-2342576, Fax: 0124-2349187 [email protected],

Website: http://www.wapcos.gov.in

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