SOLU KHOLA (DUDH KOSHI) HYDROELECTRIC PROJECT (86MW)

SOLU KHOLA (DUDH KOSHI) HYDROELECTRIC PROJECT (86MW)

Progress Report # W013

Sahas Urja Ltd. (SUL)

Hattisar, Kathmandu, Nepal

December 2019

Sahas Urja Limited Progress Report of SKDKHEP # W013

December 2019 i

Table of contents

Abbreviation and Acronyms .................................................................................................... vii

Chapter 1 About the Company .................................................................................................. 1

Description of the Company ........................................................................................... 1

Board of Directors........................................................................................................... 1

Organization Structure .................................................................................................... 2

Chapter 2 Project Description .................................................................................................... 3

Project Background ......................................................................................................... 3

Project Location and Accessibility ................................................................................. 3

Salient Features ............................................................................................................... 5

Project Layout ................................................................................................................. 8

Key dates for the project ................................................................................................. 9

Summary of activities performed .................................................................................... 9

Chapter 3 Pre-construction and Infrastructure Works ............................................................. 11

Land Acquisition ........................................................................................................... 11

Access Road and Bridge ............................................................................................... 11

Camp and Other Facilities ............................................................................................ 12

Transmission Line ......................................................................................................... 12

Physical Modelling ....................................................................................................... 13

Chapter 4 Employer’s Representative/Engineer Mobilization ................................................ 14

Chapter 5 Civil Construction Works ........................................................................................ 15

Contractor’s Mobilization ............................................................................................. 15

Explosive....................................................................................................................... 17

Civil Works ................................................................................................................... 18

5.3.1 Surface Structures .............................................................................................. 18

5.3.1.1 Headworks ...................................................................................................... 18


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5.3.1.2 Powerhouse .................................................................................................... 22

5.3.2 Underground Structures ..................................................................................... 23

5.3.2.1 Headrace Tunnel ............................................................................................ 24

5.3.2.2 Penstock Tunnel ............................................................................................. 25

5.3.2.3 Adit Tunnels ................................................................................................... 27

i) Adit 1 ......................................................................................................................... 27

ii) Adit 2.1 .................................................................................................................. 27

iii) Adit 2.2 .................................................................................................................. 27

iv) Adit 4 ..................................................................................................................... 27

Chapter 6 Hydro-Mechanical and Electro-Mechanical Works ................................................ 28

Hydro-Mechanical Works (Lot II) ................................................................................ 28

Electro-Mechanical Works ........................................................................................... 29

Chapter 7 Social Works ........................................................................................................... 30

Annex 1: Some Additional Photos………………………………………………………...…31


December 2019 iii

List of Figures

Figure 1 Organizational structure .............................................................................................. 2

Figure 2. Project Location on District Map ............................................................................... 4

Figure 3. Project Layout ............................................................................................................ 8

Figure 4.Revised Headworks - General Layout based on finalized Physical Modelling .......... 8

Figure 5. Powerhouse and Switch Yard ..................................................................................... 8

Figure 6 Penstock plan and profile ............................................................................................ 9

Figure 7. Project Access Road network ................................................................................... 11

Figure 8.Camp facilities at headworks area. ............................................................................ 12

Figure 9. Powerhouse camp area ............................................................................................. 12

Figure 10: Transmission line route in Google Image .............................................................. 13

Figure 11. Organization chart of Engineer at site .................................................................... 14

Figure 12. Camp facilities at headworks area. ......................................................................... 17

Figure 13. Camp facilities at powerhouse area. ....................................................................... 17

Figure 14. Crusher Plant at Powerhouse area. ......................................................................... 17

Figure 15. Batching plant at powerhouse area. ........................................................................ 17

Figure 16. Army camp near Surge Tunnel area ....................................................................... 17

Figure 17. Prioritized tasks at the headworks. ......................................................................... 18

Figure 18. Schematic drawing of 1st phase river diversion. .................................................... 19

Figure 19. Headworks overall view. ........................................................................................ 20

Figure 20. Bedload sluice and undersluice area....................................................................... 20

Figure 21. Upstream flood wall and headworks. ..................................................................... 20

Figure 22. Upstream flood wall. .............................................................................................. 20

Figure 23. Counterfort wall...................................................................................................... 20

Figure 24. Excavation work at remaining part of sluiceway canal. ......................................... 20

Figure 25. Progress of Intake. .................................................................................................. 21


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Figure 26. Rebar work at intake. .............................................................................................. 21

Figure 27. Rebar work at settling basin. .................................................................................. 22

Figure 28. Progress of settling basin work. .............................................................................. 22

Figure 29. Slope stabilization at powerhouse area. .................................................................. 23

Figure 30. Slope protection work. ............................................................................................ 23

Figure 31. Total tunnel progress in monthly basis. .................................................................. 23

Figure 32. Progress chart of headrace tunnel. .......................................................................... 24

Figure 33. Headrace tunnel progress. ...................................................................................... 24

Figure 34. 2nd Niche at Headrace tunnel. ................................................................................. 24

Figure 35.Junction of Adit 2.2 and HRT at outlet. .................................................................. 25

Figure 36. Tunnel face at outlet of HRT. ................................................................................. 25

Figure 37. Penstock Tunnel progress chart .............................................................................. 26

Figure 38. Rock support at tunnel. ........................................................................................... 26

Figure 39. Air ventilation at Penstock alignment. ................................................................... 26

Figure 40. Penstock own stream of Adit 4 progress. ............................................................... 26

Figure 41. View of penstock alignment. .................................................................................. 26

Figure 42. Junction of Adit 2.2 and HRT. ............................................................................... 27

Figure 43. Break through at Adit tunnel 2.2. ........................................................................... 27

Figure 44. Steel lining work at intake. ..................................................................................... 28

Figure 45. Steel lining and radial gate and stop log gate embedded frame ............................. 28

Figure 46. Steel plate rolling in progress at site. ...................................................................... 29

Figure 47. Pipe fabrication at site. ........................................................................................... 29

Figure 48. Site safety and security. .......................................................................................... 31

Figure 49. Upstream flood wall progress at headworks. ......................................................... 31

Figure 50. Stoplog gate frame installation at bedload sluice. .................................................. 31

Figure 51. Flood wall. .............................................................................................................. 31

Figure 52. 2nd Niche at Headrace tunnel. ................................................................................. 31


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Figure 53. Ventilation at Tunnel. ............................................................................................. 31

Figure 54. Technical team at valve chamber tunnel. .............................................................. 32

Figure 55. Valve chamber tunnel. ............................................................................................ 32

Figure 56. Penstock alignment. ................................................................................................ 32

Figure 57. Penstock 1st inclined section. .................................................................................. 32

Figure 58. Preparation of vertical shaft tunnel near portal 3. .................................................. 32

Figure 59. Slope stabilization at powerhouse area. .................................................................. 32

Figure 60. Control panel set up for vertical shaft work. .......................................................... 33

Figure 61. Vertical shaft excavation preparation at D/S. ......................................................... 33

Figure 62. Penstock pipe rolling at site. ................................................................................... 33

Figure 63. Penstock diameter confirmation. ............................................................................ 33

Figure 64. Technical team during site visit. ............................................................................. 33

Figure 65. Boomer drilling in tunnel. ...................................................................................... 33


December 2019 vi

List of tables

Table 1. Company details .......................................................................................................... 1

Table 2. Board of Directors ....................................................................................................... 1

Table 3. Project Salient Features .............................................................................................. 5

Table 4. Key Dates for the project ............................................................................................. 9

Table 5. Summary of activities completed till the end of August 2019. ................................... 9

Table 6. Summary of activities completed during the reporting period. ................................. 10

Table 7. Personnel of Engineer at Site ..................................................................................... 14

Table 8. List of manpower at site. ............................................................................................ 15

Table 9. Major Plant and equipment and vehicles of civil contractor at site. .......................... 16

Table 10.List of Road constructed for society ......................................................................... 30


December 2019 vii

Abbreviation and Acronyms

DoED Department of Electricity Development

DoF Department of Forest

EIA Environmental Impact Assessment

El. Elevation

GoN Government of Nepal

GWh Gigawatt hour

HCEL Hydro-Consult Engineering Limited

HEP Hydroelectric Project

HRT Headrace Tunnel

IEE Intial Environment Examination

INPS Integrated Nepal Power System

km Kilometer

kV Kilovolt

kW Kilowatt

kWh Kilowatt hour

m Meter

m.a.s.l. meter above sea level

MoEn Ministry of Energy

MoEST Ministry of Environment, Science and Technology

MoSTE Ministry of Science, Technology and Environment

MoWR Ministry of Water Resources

MW Megawatt

NEA Nepal Electricity Authority

PPA Power Purchase Agreement

PPM Part Per Million

RoR Run of River

SKDKHEP Solu Khola (Dudh Koshi) Hydroelectric Project

SUL Sahas Urja Limited

Sq. km. square kilometer

TOR Terms of Reference


December 2019 1

Chapter 1 About the Company

Description of the Company

Sahas Urja Limited (SUL) established on 2071 B.S comprises of a group of veterans in the field of entrepreneurship having innovative ideas of modern enterprises with advanced development strategies and management concepts. SUL commits to create superior value for all its shareholders and stakeholders and aimed to be among most admired and trusted company in the country. It has planned to contribute to the national economy through accelerated hydropower development.

Table 1. Company details

Name of the Company Sahas Urja. Ltd. Type Public Limited Company Address Hattisar, Kathmandu Contact no. 01-4419182, 01-4419183 Email [email protected] Established as

Private Limited Company 2070/10/19 B.S. Public Limited Company 2071/05/29 B.S.

PAN no. 601799749 Registration no. at Office of Company Registrar 126624/071/072 Department of Industry Registration No 3706 (2073-12-30)

Board of Directors

Table 2. Board of Directors

Name of Director Position Mr. Him Prasad Pathak Chairman Mr. Sushil Thapa Managing Director Mr. Mukti Ram Pandey Director Mr. Bhoj Bahadur Shah Director Mr. Min Raj Kandel Director Mr. Mahendra Kumar Giri Director Mr. Paritosh Paudyal Director


December 2019 2

Organization Structure

In any organization, the organizational structure plays a vital role in achieving the success. This structure defines the role of each persons involved in the company. Following chart elaborates the organization structure of this company:

Figure 1 Organizational structure

Both site team and head office team will have a technical division and support division. Whereas the head office team comprise of finance division and site team has public relation division.

Board

Managing Director

Project Manager

Site Team

Technical Division

Support Division

Public Relation & Environment

Head Office Team

Technical Division

Finance Division

Support Division

Advisor

Chairman


December 2019 3

Chapter 2 Project Description

Project Background

Solu Khola (Dudh Koshi) Hydroelectric Project (SKDKHEP) is a Run of River (RoR) type project with installed capacity of 86 MW that lies in Solukhumbu district of Province no.1 (Sagarmatha Zone in the Eastern Development Region) of Nepal. The proposed headworks site is located near Bhadaure Village in Solududhkunda Municipality. The tunnel passes underneath of Kattike, Gairi, Pokhari Bhanjyang, Phalate and Pairatham of Thulung Dudh Koshi Gaupalika. The proposed powerhouse site is located at Maikubesi of Thulung Dudh Koshi Gaupalika at about 1km upstream from the suspension bridge over Dudh Koshi River at Jaleshwor Mahadev. The major structures of the project are diversion weir, undersluice, intake, approach canal, surface settling basin, headrace tunnel, surge tunnel, underground penstock, surface powerhouse and tailrace box culvert. The energy generated from the project will be evacuated to the Integrated Nepal Power System (INPS) at the proposed sub-station at Lamane in Solududhkunda Municipality of Solukhumbu District. Geographically, the

physical area of the project lies within longitudes of 863735E to 864115E and latitude of

272153N to 272515N.

DoED had awarded the survey license to the company on 2065-07-25 to conduct the necessary investigations, feasibility study and Environmental Impact Assessment (EIA) of the project. Upon completion of feasibility study and EIA of the project in October 2013, the company applied for the generation license with the DoED and presented among the concerned officials. DoED accordingly awarded the Generation License on 2071-06-02 (18 September 2014).

The application for PPA was filed in February 2012 and regular follow ups were made with the Power Trade department of NEA. After the introduction of new tariff structure for projects up to 100 MW, PPA with NEA was concluded on 25 February 2015.

The Financial Closure has been concluded with 10 Banks and Financial Institution with the lead by Nepal Investment Bank Limited (NIBL) on 2073/4/20. The company was involved in acquisition of private land and development of infrastructures like access road and camp facilities of the Project.

Project Location and Accessibility

The proposed headworks site lies at an elevation of 1264.0 m near Gairi Gaun of Tingla of Solududhkunda Municipality and the powerhouse is located at an elevation of 643 m at Maiku Besi of Thulung Dudh Koshi Gaupalika.

The nearest motorable road head from the headworks site is at Ramite on Sagarmatha highway from where an agricultural road branch towards SKDKHEP headworks site. The Headworks site is about 257 km from Kathmandu including 250 km black topped road up to Ramite and 9 km earthen road from Ramite to headworks site. Similarly, there is accessibility from Mirchiya, East-West highway to Ramite through Katari-Ghurmi-Okhaldhunga which is 149 km in length.


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Similarly, the nearest road head from the powerhouse site is Panchan which is 19 km from Jor-Buddha, Okhaldhunga- Salleri highway.

Figure 2. Project Location on District Map


December 2019 5

Salient Features

The salient features of the Solu Khola (Dudh Koshi) Hydroelectric Project 86MW, are presented on Table 3

Table 3. Project Salient Features

a. Project Information

Province no. 1

District Solukhumbu

Location Latitude 27°21’53” N to 27°25’15” N

Longitude 86°37’35” E to 86°41’15” E

Intake Site Solududhkunda Municipality

Powerhouse Site Thulung Dudh Koshi Gaunpalika

b. General Data

Name of River Solu Khola

Type of Scheme Run-of-river

Head Gross 614.7 m

Net 599.0 m

Design Discharge 17.05 m3/sec

Installed Capacity 86,000 kW

Energy Dry Season 101.27 GWh

Wet Season 419.94 GWh

Total Annual 520.20 GWh

c. Hydrology

Catchment Area 454 km2

40% Percentile Discharge 17.05 m3/sec

Design Flood (1 in 100 yr. return) 475 m3/s

d. Diversion Weir

Type of Weir Gravity

Length 31.8 m

Weir Crest Level El. 1,262.00masl

Foundation Level El. 1,248.50masl

e. Sluiceways

1. Bed Load Sluice

Openings 1 No. 3.0 m wide × 3.0 m high

Invert Level El. 1,253.50 masl

Length 15.85 m

2. Undersluice

Openings 3 No. 1.5m wide × 1.0 m high

Invert Level El. 1256.00 masl

Length 30.85 m


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3. Sluiceway Canal

Openings 1 No. 4.0 m wide × varies high

Length 86.36 m

g. Trash passage

Opening 1 No. 3.10 m wide × 4.65 m high

Length 13.30 m

h. Fish Ladder

Opening Size 1 No. 2.00 m wide × 1.52 m high

Length 50.65 m

h. Intake Structure

Type Side intake

Openings 3 No. 4.0 m wide × 2.3 m high

Invert Level El. 1,258.00 masl

i. Gravel Trap

Size 3 No. 5m × 5m (L x B) Bed load size to trap 5 mm Flushing Pipe 3.0 Nos, 26.55m in total 0.5m Dia

j. Approach Culvert

No. 3

Size 2.6 m wide × 2.6 m high

k. Settling Basin

No of Bays 3

Inlet Transition 22 m

Dimensions 85.0 m long × 9.0 m wide × 5 m high

Head pond Size 15.20 m

Nominal Size of Trapped Particle 0.15 mm Trap Efficiency 90%

Power Conduit

l. Headrace Box Culvert

Length 34.50 m

Dimensions 1 No. 4.5 m wide × 4.5 m high

m. Tunnels – ‘Inverted D Shaped’

With Finished Inverted D Dimensions 4.0 m wide × 4.25 m high

Headrace Tunnel Length 4469.61 m Adit 1 92 m

Adit 2.1 27 m

Adit 2.2 269 m Adit 4 289 m With Finished Inverted D Dimensions 4.0 m wide × 4.0 m high

Surge Tunnel 375.00 m


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n. Penstock pipes

Inclined section 1 220 m

Drop Shaft 1 189 m deep

Inclined section 2 534 m long

Drop Shaft 2 252 m deep

Inclined section 3 669 m long

Total length to bifurcation 1864 m

Pipe Steel Grade 350MPa and 460 MPa

Internal Diameter and Length Diameter varies from 2.50 m to 2.10 Thickness 12 mm to 46 mm

o. Powerhouse

Type Surface

Dimensions 49 m Long × 15.25 m Wide × 28.23 m High

Turbine setting level El 647.30 masl

No. and Type of turbines 3 No. Vertical axis Pelton

Speed of Turbine 750 RPM

Total Installed capacity 86.0 MW

Generators Three phase, Synchronous, 34.6 MVA

p. Tailrace Canal- Length and Type 70 m Long Reinforced Concrete Conduit

q. Transmission Line – Project to Proposed Tingla Substation

12 km Long 132 kV

r. Switchyard 60 m Long × 50 m Wide


December 2019 8

Project Layout

General Project layout with the major projects components is shown in Figure 3.

Figure 3. Project Layout

The physical model conducted at Hydro Lab suggested new arrangement of headworks. The revised intake and waterway are shown on Figure 4, while the powerhouse is shown on Figure 5

Figure 4.Revised Headworks - General Layout based on finalized Physical Modelling

Figure 5. Powerhouse and Switch Yard

The Design team after the field visit proposed an alternative for the penstock alignment. The proposed new penstock alignment (black line) is show on the figure below.


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Figure 6 Penstock plan and profile

Key dates for the project

The key dates for the project are listed as below:

Table 4. Key Dates for the project

S. No. DESCRIPTION DATE

1 PPA Signed Date 11/13/2071 Amendment Date 9/11/2073 Transfer Date to Sahas Urja Limited 4/11/2074

2 RCOD 6/10/2077

3 FINANCIAL CLOSURE SIGNED DATE 4/20/2073

4 GENERATION LICENCE Received Date 6/2/2071 Transfer Date to Sahas Urja Limited 2/1/2074

Summary of activities performed

Following tables presents the key activities and progress of the project till November, 2019.

Table 5. Summary of activities completed till the end of August 2019.

SN Completed Major Activities Dates1. Mobilization of Employer’s Representative/Engineer at site. Feb. 2018

2. Construction of bunker for Army camp and explosive storage. Apr. 2018

3. HM tripartite agreement July.2018

4. IEE for Transmission line Approved. Feb. 2019

5. Contract agreement with CE Construction for construction of civil works. Feb. 2019

6. Contract of S4 system for sediment flushing of Settling Basin-Completed. May 2019


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SN Completed Major Activities Dates 7. Adit 1 Tunnel excavation work completed. Jun. 2019

8. Adit 4 Tunnel excavation work completed. Jun. 2019

9. Penstock Tunnel 1st inclined section completed. Jun 2019

Table 6. Summary of activities completed during the reporting period.

SN Recent Activities Dates 1. Adit 2.2 tunnel excavation work completed. Sep. 2019 2. Penstock tunnel 3rd inclined section U/S of Adit 4 completed. Oct. 2019 3. Penstock pipe rolling machine installation at site complete. Oct. 2019 4. Concreting of Undersluice walls. Ongoing 5. Concreting of Intake and Gravel Trap. Ongoing 6. Concreting of bedload sluice canal. Ongoing 7. Concreting work at settling basin walls. Ongoing 8. Headrace Tunnel excavation from Inlet. Ongoing 9. Headrace Tunnel excavation from Outlet. Ongoing 10. Valve Chamber Tunnel excavation works. Ongoing 11. Penstock Tunnel 2nd inclined section (from portal 3). Ongoing12. Penstock Tunnel 3rd inclined section D/S from Adit 4. Ongoing13. Powerhouse excavation. Ongoing14. Slope protection work at powerhouse area. Ongoing15. Installation works of Bedload sluice and undersluice gate embedded parts. Ongoing16. Vertical shaft-2 excavation site preparation work. Ongoing


December 2019 11

Chapter 3 Pre-construction and Infrastructure Works

This chapter covers the pre-requisite works required before the major construction work begins. Following topics are covered by this topic and described in detail.

Land Acquisition

Based on different types of ownership, there are two types of lands required by the project i.e. governmental and private. Within this frame these lands are either leased till the project period or purchased. Most of the Private land required for the project component has already been purchased and taken in lease and few are in the process.

From the Ministry of Land Reform and Management approval for acquisition of 239 Ropani of land was obtained in the month of September 2017.

Contract agreement with the Department of Forest regarding tree cutting and land use has been done in the month of November 2017. According to contract, the area of government land which is used for the construction of structures of the project has to be handed over to the government. The company has handed over 86.78 Ropani of land till the end of reporting period.

Access Road and Bridge

The road length from Ramite (nearest road head in Okhaldhunga - Salleri highway) to headworks is 9 km, then from Headworks to Powerhouse is 21.71 km and crosses the Solu River twice. Most of the sections of access road were new track and some were village roads. The projected has upgraded all the roads.

Figure 7. Project Access Road network


December 2019 12

The powerhouse is also accessible via Salleri-Tumse-Panchan Road or Jor-Buddha- Tumse -Panchan. Road from Tumse to Panchan was upgraded by SUL and also maintaining as and when required. From Panchan onwards project access road is available up-to Maikhubesi i.e. Powerhouse location.

Bailey Bridge

Construction of Two bridges, Bridge-1 to access the headworks and Bridge-2 to connect headworks and powerhouse in Solu Khola are already completed and in operation. Bridge -1 and Bridge-2 are of 30 R and 70 R according to Road Standards. The span of these bridge is 120 feet. Regular maintenance of the Bridge is under the scope of CE Construction Pvt. Ltd.

Camp and Other Facilities

Camp establishment at Bhadaure near Headworks, Bhorleni, near Adit-2 and Surge tunnel area and

Maikhubesi near powerhouse has been completed.

There are five building blocks at headworks. Two for residential quarters for senior officers, one for driver and guard room, one kitchen and one office building. All the buildings are in use.

Similarly, there are seven blocks at powerhouse with four residential quarters, one office block, one kitchen block and one Covered hall. The camp is being used for accommodation since December 2017. shows the camp facilities at headworks and powerhouse area.

Figure 8.Camp facilities at headworks area. Figure 9. Powerhouse camp area

The camp facilities include furniture, mesh utensils, office equipment’s, TV, internet, recreational items etc.

Transmission Line

Terms of Reference (ToR) of IEE for transmission line was approved in September 2017 and IEE report was approved in the month of February 2019 by DoED. Currently land required for transmission line is being identified and the land acquisition work will be started soon. We have applied for generation license with submission of required documents. Figure 10 shows the transmission line route with the position of tower in google map.


December 2019 13

Figure 10: Transmission line route in Google Image

Physical Modelling

Physical hydraulic modelling of headworks was conducted in Hydro Lab Pvt. Ltd from May 2016 to March 2018. Based on the results of this model, revision of headworks arrangement was deemed necessary. After reviewing the physical model Professor Dr. Haakon Stole suggested some major changes in the arrangements. These were further tested in the laboratory for model study and was found satisfactory. The design and construction of headworks is being done accordingly.


December 2019 14

Chapter 4 Employer’s Representative/Engineer Mobilization

Contract was awarded to Consortium of Hydro-Consult Engineering Limited and FICHTNER GmbH & Co.KG on 18th December 2017 as an Employer’s Representative. A team of Consortium is at site. As the modality of the Contract has been changed from turnkey to quantity based, the role of Employer’s Representative has changed to the role of Engineer as per the FIDIC and the same is in process.

Figure 11. Organization chart of Engineer at site

Currently, there are 33 personnel at site. Table 7 shows the list of site personnel of Engineer.

Table 7. Personnel of Engineer at Site

S. No. Job Classification Number of personnel

1. Technical 25

2. Administrative / Account 2

3. Support Staff 6

Total 33


December 2019 15

Chapter 5 Civil Construction Works

Sahas Urja Limited awarded the Contract to CE Construction Pvt. Ltd. on 11th February 2019 with the commencement date as 25th Feb 2019. The model of contract is quantity based. The kick-off meeting was held in site between SUL, CE, HCE and FIH at site on 4th Mar 2019. However, CE began mobilizing at site on 19th February 2019. Since then CE has been continuously working in site.

Contractor’s Mobilization

After the contract, CE Construction was mobilized at site on February 2019. Previous Contractor had built camps at headworks and powerhouse areas. CE construction is using the same camp facilities with modifications as per their requirements. Table 8 and Table 9 below shows the manpower, plant and equipment of the contractor at site.

Table 8. List of manpower at site.

S.N. Designation Number Remarks1. Project Manager 1 2. Assistant Project Manager 3 3. Civil Engineer 11 4. Electrical Engineer 1 5. Mechanical Engineer 2 6. Supervisor, foreman and mechanic 35 7. Surveyor 9 8. Geologist 4 9. Public Relation Officer 3 10. Accountant, procurement, Store keeper 9 11. Draftsman, overseer, Sub-overseer 8 12. Lab Assistants 14 13. Health and Safety Officer 6 14. Blaster Welder, Plumber, Electrician, 33 15. Information Technician 1 16. Tradesman 122 17. Cooks and house keeper 20 18. Skilled and unskilled labor 312 19. Security Guard 24

Total 618


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Table 9. Major Plant and equipment and vehicles of civil contractor at site.

S. No. Particulars Number 1. Boomer 4 2. Excavator 10 3. Crane (30 ton) 1 4. Robodrill 1 5. Batching plant (18m3/h & 25m3/h, 35 m3/h) 4 6. Crusher Plant 2 7. Dump Truck 19 8. Generator (Total 3630 kVA) 16 9. Light Vehicle (Hilux, camper) 9 10. Robotic Shotcrete Machine 2 11. Ambulance 1 12. Water tank 2 13. Forklift machine 1 14. Loader 8 15. Hagg loader 4 16. Ventilation fan 11 17. Mini-excavator 2 18. Compressor 14 19. Concrete Mixer 7 20. Manual Shotcrete machine 6 21. Grouting Machine 6 22. Transit Mixture 8 23. Concrete pump 1 24. Cutter Machine Electric 2 25. Welding Machine 16 26. Jack hammer Pneumatic 25 27. Drill Gun Machine Pneumatic 7 28. Welding machine 11 29. Rod bending and cutting machine 4 30. Ventilation fan 11 31. Flat bed/Trailer 1

Camp for contractor’s personnel are constructed at headworks area, surge tunnel area and powerhouse area. There are two batching plants installed at headworks area, one batching plant of 18m3/h capacity is installed at surge tunnel area and other batching plant of 35m3/hr is at powerhouse area. Similarly, there is one crusher plant at headworks area and other near powerhouse area. All crusher plants and batching plants at different places are smoothly running. The following figures shows contractor’s camp at different area, crusher plants and batching plant.


December 2019 17

Figure 12. Camp facilities at headworks area.

Figure 13. Camp facilities at powerhouse area.

Figure 14. Crusher Plant at Powerhouse area.

Figure 15. Batching plant at powerhouse area.

Explosive

Approval for the procurement, supply, storage of explosives and blasting works have been received from the Ministry of Defense, Ministry of Energy and Ministry of Foreign Affairs. Construction of Storage Bunker at Site is complete near Bhorleni camp. Army has started operating from the camp since May 2018. View of army camp and explosive bunker is shown in Figure 16.

Figure 16. Army camp near Surge Tunnel area


December 2019 18

Civil Works

The civil works is further divided into surface and underground structures. Surface structures includes headworks components and powerhouse components. However, the underground structures consist of Headrace Tunnel, Surge Tunnel, Adit Tunnels and Penstock Tunnel.

5.3.1 Surface Structures

Surface structures includes the weir, Undersluice, bedload sluice, intake, gravel trap, approach canal, settling basin, powerhouse and switchyard. Progress of these structures are described in the sub-headings below:

5.3.1.1 Headworks

Before starting the headworks main components, the first stage is river diversion. This stage enables to work in the River. Basically, River diversion occurs in two stage, however, the contractor has proposed a three-stage river diversion to ease the construction of headworks. The contractor has prioritized their headworks activities as numbered below in the Figure 17. Task numbered 1 ,2 and 3 base work are completed and currently vertical walls concreting work is ongoing and base work of task 4 is ongoing at site.

Figure 17. Prioritized tasks at the headworks.


December 2019 19

River Diversion

The proposed river diversion works by CE consists of coffer dam construction in the middle of Solu Khola allowing the river to pass from the right side. This enables the construction of the undersluice, intake and bedload sluice in first dry season.

Figure 18. Schematic drawing of 1st phase river diversion.

Cofferdam construction for 1st stage river diversion at headworks has been completed and the contractor is planning for 2nd stage river diversion work.

Weir, Bedload Sluice, Undersluice and Sluiceway canal

The diversion weir is a gravity weir of 31.8 m long crest with inclined floor stilling basin. The weir crest is fixed at 1262.0 masl and invert level of intake at 1258.0 masl to divert the design discharge of 17.05 m3/sec with additional 15% for gravel trap and settling basin flushing. The head over the weir crest during 1 in 100 years flood, which is equivalent to 475.0 m3/s, is calculated to be about 3.6 m, which means that the maximum water level will be at 1264.10 masl considering the undersluice gate opening. A low head bed load sluices one gate and three undersluice are proposed on the left side of the diversion weir beside intake for conventional hydraulic flushing of bed load. The sluiceway canal is about 86.36m long and 4m width which carries the discharge conveyed by undersluice, bed load sluice and gravel flushing.

The concreting work of panel 1 and 2 of Sluiceway Canal has been completed. Currently, undersluice concreting work is in progress rebar and form work of undersluice is going on. Till the end of reporting period 3600 m3 of concreting work has been completed. Work of remaining part of bedload sluice panel 3,4,5 and panel 6 is also going on. Figure below shows the progress of concreting works at bedload sluice, undersluice area and flood wall.


December 2019 20

Figure 19. Headworks overall view.

Figure 20. Bedload sluice and undersluice area.

Figure 21. Upstream flood wall and headworks.

Figure 22. Upstream flood wall.

Figure 23. Counterfort wall.

Figure 24. Excavation work at remaining part of sluiceway canal.


December 2019 21

Intake and Gravel Trap

RCC side intake is proposed as the submerged orifice type intake, located immediately upstream and adjacent to the bed load sluice to withdraw the design discharge of 17.05 m3/s including the discharge for the flushing. The invert level of the intake is fixed at 1258.0 masl that the boulder up to 300 mm is allowed to enter through the trash rack of intake and can be flushed back to the river downstream through gravel trap flushing. The intake will have 3 orifices each 4.0 m high and 2.3 m wide. In front of the intake opening, a coarse trash rack of 300 mm c/c passage gap is placed which covers the span for two openings. Three hopper shaped gravel trap of 5.0 m width and 5.0 m height each is provided immediately after intake chamber to trap coarse particles of size greater than 5 mm. The slope of hopper along the profile starts from 1 m D/S of Inlet Gate.

The Excavation work of intake is complete and currently concreting work of intake is going. Similarly, the gravel flushing base work is complete and the vertical wall work is going on. Till the end of reporting period about 800 m3 of concreting work has been completed. The steel lining work at gravel flushing area is complete. The figure below shows the progress of intake and gravel trap area.

Figure 25. Progress of Intake.

Figure 26. Rebar work at intake.

Approach Canal

Immediately after gravel trap, three individual approach culverts having different length, inclined bends and slopes are provided to carry the design discharge up to the settling basin. The shape of the culvert is square with dimension 2.6 m * 2.6 m.

Settling Basin and Approach Culvert

A hopper type buried settling basin with three chambers is proposed on the left bank of Solu Khola. Each chamber is 85 m long, 9.0 m wide with effective depth of 4.0 m. Mechanical flushing is proposed for flushing.

The contractor has completed the excavation work of settling basin. Base work of all four panel has been completed. The vertical shear wall concreting is going on at the mean time the hopper concreting work is in progress. Currently the concreting of hopper sections of different panels of settling basin


December 2019 22

is going on. Till the end of reporting period about 30,000 m3 earthwork have been excavated and 5000 m3 concreting work has been completed. The figure below shows the work progress of settling basin area.

Figure 27. Rebar work at settling basin. Figure 28. Progress of settling basin work.

Kholsi Protection

To collect water from kholsi, drainage arrangement has been made at the hill side. The water from kholsi in the main settling area is collected through cascade drop which diverts water to D/S and U/S side by earth fill slope to the main drain canal. It is a trapezoidal concrete channel of base width 2.5 m and height 1.75m designed to carry the discharge of 15.21 m3/s.

5.3.1.2 Powerhouse

The proposed powerhouse is located at rock on the right bank of the Dudh Koshi River few meters

above the high flood level of the 100 years return period. The elevation of the powerhouse was fixed such that it is free from the risk of flooding at the Dudh Koshi River during the monsoon season. To ensure safety, flood protection wall near the powerhouse is also designed along the right bank of Dudh Koshi River. The powerhouse is 60.0 m long, 16.2 m wide and 18.0 m high with reinforced concrete structural elements in the main building with shear walls, brick walls, aluminum composite panels (ACP) and CGI sheet roofing.

A 70.0 m long tailrace culvert with sectional dimension 2.00 m wide and 1.90 m high for separate unit, 4.60 m wide and 1.9 m high for combined unit and 3.55 m wide and 1.9 m high for section between first and last merge point will pass the design discharge to the Dudh Koshi river at right bank of the river. Currently the excavation work and slope stabilization work are going on at site. Figure below shows the excavation area and slope protection work.


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Figure 29. Slope stabilization at powerhouse area. Figure 30. Slope protection work.

5.3.2 Underground Structures

Headrace tunnel has been proposed as a low-pressure tunnel from the surface settling basin to the surge tank. The total length of the headrace tunnel is 4469.0 m. An Adit tunnel of 93 m length is excavated at 154m downstream from the inlet portal. Similarly, outlet Adit tunnel is proposed before the surge tunnel. Headrace tunnel has been proposed as a low-pressure tunnel from the surface settling basin to the surge tank. However, the size of the tunnel is taken as 4m width and 4.25 m height considering the required height for the vehicle movement and for the provision of the ventilation.

The dimension of surge tunnel is 4.0 x 4.0 m with a slope length of 375.0m. The surge analysis shows the maximum surge level is 1272.28masl and minimum level of down surge level as 1246.78masl.

The chart below shows the monthly progress at tunnel works by the civil contractor after the mobilization on February.

Figure 31. Total tunnel progress in monthly basis.

30

228 235

359

300

432366

220

321

Mar Apr May Jun Jul Aug Sep Oct Nov

Monthly Tunnel Progress


December 2019 24

5.3.2.1 Headrace Tunnel

Inlet Portal which is after the power culvert is the main entrance for the conveyance of water to the headrace tunnel. Inverted D shaped tunnel with width of 4.0 m x 4.25 m finished diameter shall be the main part of the water conveyance system with a total length of 4469m. There are two Adit tunnels in Headrace tunnel, Adit 1 and Adit 2.2. these tunnels ease the excavation of headrace tunnel.

Inlet portal preparation was completed in the month of May 2018. After the portal work Headrace tunnel excavation is in progress. Till the end of this reporting period 989 m tunnel excavation has been completed, previous contractor had excavated 173 m and CE had completed 816 m of tunnel from the inlet face. Temporary support and permanent support are also in progress where necessary. Similarly, after the completion of 1st inclined section of penstock alignment headrace tunnel excavation is going on from Adit 2.1. Till the end of reporting period 315 m tunnel excavation has been complete from the outlet face. About 29 % headrace tunnel excavation has been completed till the end of reporting period. The figure below shows the tunnel progress of HRT.

Figure 32. Progress chart of headrace tunnel.

Figure 33. Headrace tunnel progress.

Figure 34. 2nd Niche at Headrace tunnel.

0 98944694153.91

1150

1350

1550

0 500 1000 1500 2000 2500 3000 3500 4000 4500

Elevation (m)

Tunnel chainage (m)

HRT tunnel

Completed tunnel


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Figure 35.Junction of Adit 2.2 and HRT at outlet. Figure 36. Tunnel face at outlet of HRT.

5.3.2.2 Penstock Tunnel

The penstock tunnel is used to convey the water from surge shaft to the turbine. It is an underground structure. Penstock alignment is of total length 1864 m up to the point of bifurcation. It consists of three inclined sections and two vertical shafts. The penstock pipe starts after the surge shaft with an invert level of 1227.36 having inclined portion of 220 m length and first vertical drop of 189.0 m length. Likewise, the pipe passes through the inclined portion of 534 length, and second vertical drop of 252 m length. After second vertical drop, it runs through an inclined portion of 669 m length up to bifurcation. Altogether, the penstock alignment has four bends before bifurcation. The vertical part is penstock casing with concrete infill and the inclined part has the support piers at 5 m c/c spacing. There are two Adits: Adit 2.1 at the start of first drop shaft and Adit 4 near the powerhouse site to ease the construction of the penstock pipe.

The tunnel excavation for penstock alignment has started from different face. First inclined section of length 220 m has been completed from Adit 2.1

One portal is prepared at the start of 2nd vertical shaft, this portal facilitates the excavation of inclined section of penstock alignment towards upstream side and vertical shaft 2. Due to poor geology the excavation of tunnel is going on in slow speed. Preparation for the excavation of drop shaft 2 is also going on. Collar installation work is going on. Till the end of reporting period 280 m tunnel excavation upstream of portal has been completed from that face.

After the completion of Adit 4 penstock section upstream of Adit junction has been in progress. Till the end of the reporting period 324 m penstock tunnel has been completed at third inclined section. Currently the preparation for drop shaft 2 excavation is going from downstream side as well. Similarly, tunnel excavation towards D/S from Junction at Adit 4 has been in progress till the end of reporting period 45 m of tunnel excavation has been completed. About 45% of penstock tunnel excavation has been completed till the end of reporting period. The figure below shows the Progress of penstock tunnel.


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Figure 37. Penstock Tunnel progress chart

Figure 38. Rock support at tunnel.

Figure 39. Air ventilation at Penstock alignment.

Figure 40. Penstock own stream of Adit 4 progress.

Figure 41. View of penstock alignment.

4689

4509

4469 4689

52234943

52235592

450

550

650

750

850

950

1050

1150

1250

4460 4960 5460 5960

Elevation

Tunnel Chainage

Penstock Tunnel

Completed tunnel


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5.3.2.3 Adit Tunnels

i) Adit 1

Adit 1 is 92 m long and it meets the headrace tunnel at chainage of 0+154.00 m. The location of portal of Adit 1 lies near Bailey Bridge 1 at headworks area. The purpose of Adit 1 is to continue the headrace tunnel from upstream side as the other civil works of settling basin and power canal disturb the tunnel work near inlet portal. This Adit now facilitates the smooth construction work of headrace tunnel work in later days. Adit 1 excavation has been complete, the breakthrough was complete on June 2019.

ii) Adit 2.1

The Adit 2.1 which is located near the surge tunnel is in progress. This Adit now facilitates the

construction of vertical shafts. Two new Adits i.e. Adit 2.1 and 2.2 has been incorporated to expedite the headrace tunnel excavation. Adit 2.1 is 27 m long and fully excavated by previous contractor. Currently 1st inclined section of penstock alignment excavation upstream of Adit 2.1 is complete and headrace tunnel excavation is going on.

iii) Adit 2.2

The new location of Adit 2.2 lies in headrace tunnel which is located upstream of Adit-2.1. Adit 2.2 has been incorporated to expedite the headrace tunnel excavation. This tunnel is of length 268.7 m and the total length excavation has been completed. The valve chamber tunnel of length 40 m has been in progress from this tunnel. Figure below shows the progress, portal work and the tunnel excavation work of Adit tunnel.

Figure 42. Junction of Adit 2.2 and HRT.

Figure 43. Break through at Adit tunnel 2.2.

iv) Adit 4

Adit 4 located near powerhouse is of length 289 m and of internal size 4.0 m inverted D shape. Tunnel excavation of length 289 m has been completed currently penstock tunnel of 3rd inclined section downstream section is continuing.

All the Adit tunnels excavation work has been completed till the end of reporting period.


December 2019 28

Chapter 6 Hydro-Mechanical and Electro-Mechanical Works

Hydro-Mechanical Works (Lot II)

The penstock pipe is used to convey the water from surge shaft to the turbine. It is an underground structure. The pipe is provided with the inclined and vertical tunnel shaft of diameter 4.3 m and 3.9 m respectively. The penstock pipe diameter varies from 2.5 m to 1.2 m and finally 0.9 m at the portion of main inlet valve. Likewise, the thickness of the penstock pipe varies from 12 mm to 46 mm. The penstock pipe starts after the surge tunnel with an invert level of 1227.36 having inclined portion of 220 m length and first vertical drop of 189 m length. Likewise, the pipe passes through the inclined portion of 538 m length, and second vertical drop of 252 m length. After second vertical drop, it runs through an inclined portion of 669 m length up to bifurcation. Altogether, the penstock alignment has four bends before bifurcation. The vertical part is penstock casing with concrete infill and the inclined part has the support piers.

Machhapuchhre Metal and Machinery Works Pvt. Ltd (Hydromechanical Contractor 3MW) has been mobilized at site. Installation of Steel lining works at bedload sluice and gravel flushing area is almost complete where as that of undersluice is continuing. Similarly, the steel lining work at the base of intake is also going on at the site. Stop log embedded parts at undersluice and bedload sluice is complete similarly the embedded part of radial gate at undersluice and bedload sluice is in progress at site. Similarly, after the construction of yard for pipe rolling the 3MW contractor has completed the installation of penstock pipe rolling machine and it has been commissioned as well. Most of the metal plate required for the penstock pipe fabrication has been ordered and are in the Birgunj boarder. Border clearance process is going on. Figure below shows the progress of hydromechanical contractor at site.

Figure 44. Steel lining work at intake. Figure 45. Steel lining and radial gate and stop log gate embedded frame


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Figure 46. Steel plate rolling in progress at site. Figure 47. Pipe fabrication at site.

Electro-Mechanical Works

Considering the head and flow available, calculated number of jets, so as to achieve maximum efficiency with the jet ratio of 12.21 was found to be six (6). The overall design has been based on six (6) numbers of jets. Pelton turbine with vertical shaft alignment was selected. The elevation of the turbine axis was set at 647.30 masl. Total no. of turbines is 3 with a capacity of 30,400 KW each.


December 2019 30

Chapter 7 Social Works

The project has been contributing in many social activities within the project affected areas. Major sector of corporate social responsibility involves road expansion/upgradation, education, health services, water supply, irrigation, vocational trainings, land development works.

The total widening and upgradation completed by the project is 17 km which includes Ramite- Surge Tank of LSHEP, Maikhu Besi to Suspension Bridge, Tumse to Panchan, Salyan to Thuldhunga and Baspura road.

Total of 7.6 km New track has been opened by the project which includes Rolim Road and Village road in Bhorleni.

Pipes (32-500mm) for different purpose like water supply and irrigation has been provided

by the project in Bhorleni-Deurali- Panchan Khanepani etc. Many water Tanks has been repaired/ reconstructed in the village.

9 nos. of stretchers were distributed to each ward of Panchan, one health assistant is appointed in health post at Panchan.

Vocational Trainings were organized from 19th March to 18th of April 2018. With 109 participants from the affected area.

Land Development works were carried out in many locations as per the local demands.

Landslide debris clearance at various locations within the project affected area.

Different social new track opened and upgraded road are listed in table below.

Table 10.List of Road constructed for society

S. N. Road Description Total length (km) Work Executed

1. Ramite to Surge tank of LSHEP (82mw)

2.5 Widening and upgrading completed

2. Maikhubesi to old suspension bridge

0.7 Upgrading

3. Tumse to Panchan 9.3 Widening and maintenance4. Rolim Road 6 New Track opening 5. Road to Salyan from Thuldhunga 2.5 Widening and maintenance6. Village Road at Baspura 2 Widening and maintenance7. Village Road at Bhorleni 1.6 New Track opening


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Annex:1 Some Additional Photos

Figure 48. Site safety and security.

Figure 49. Upstream flood wall progress at headworks.

Figure 50. Stoplog gate frame installation at bedload sluice.

Figure 51. Flood wall.

Figure 52. 2nd Niche at Headrace tunnel. Figure 53. Ventilation at Tunnel.


December 2019 32

Figure 54. Technical team at valve chamber tunnel.

Figure 55. Valve chamber tunnel.

Figure 56. Penstock alignment.

Figure 57. Penstock 1st inclined section.

Figure 58. Preparation of vertical shaft tunnel near portal 3.

Figure 59. Slope stabilization at powerhouse area.


December 2019 33

Figure 60. Control panel set up for vertical shaft work. Figure 61. Vertical shaft excavation preparation at D/S.

Figure 62. Penstock pipe rolling at site. Figure 63. Penstock diameter confirmation.

Figure 64. Technical team during site visit.

Figure 65. Boomer drilling in tunnel.

Documents

SOLU KHOLA (DUDH KOSHI) HYDROELECTRIC PROJECT (86MW)