SOLU KHOLA (DUDH KOSHI) HYDROELECTRIC PROJECT (86MW) · Figure 6 Penstock plan and profile ... Figure 37. Support work at penstock section. ... Similarly, the nearest road head from

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

Progress Report # W012

Sahas Urja Ltd. (SUL)

Hattisar, Kathmandu, Nepal

September 2019

Sahas Urja Limited Progress Report of SKDKHEP # W012

September 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 ................................................................................................... 26

i) Adit 1 ......................................................................................................................... 26

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

iii) Adit 2.2 .................................................................................................................. 28

iv) Adit 4 ..................................................................................................................... 28

Chapter 6 Hydro-Mechanical and Electro-Mechanical Works ................................................ 29

Hydro-Mechanical Works (Lot II) ................................................................................ 29

Electro-Mechanical Works ........................................................................................... 30

Chapter 7 Social Works ........................................................................................................... 31

Annex 1: Some Additional Photos………………………………………………………...…32


September 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 Employer’s Representative 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 area. ..................................................................................................... 20

Figure 20. Rebar and form work in progress ........................................................................... 20

Figure 21. Work progress at undersluice. ................................................................................ 20

Figure 22. Bedload sluice ........................................................................................................ 20

Figure 23. Intake area. ............................................................................................................. 21

Figure 24. Gravel flushing area work progress. ....................................................................... 21

Figure 25. PCC of settling basin. ............................................................................................. 22


September 2019 iv

Figure 26. Rebar work. ............................................................................................................ 22

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

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

Figure 29. Excavation at powerhouse area. ............................................................................. 23

Figure 30. Shotcrete work for slope stabilization work. .......................................................... 23

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

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

Figure 33. Holes Drilled at HRT.............................................................................................. 24

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

Figure 35.Junction of Adit 2.2 and headrace tunnel alignment. .......................................... 25

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

Figure 37. Support work at penstock section. .......................................................................... 25

Figure 38. 1st horizontal section. ............................................................................................. 25

Figure 39. Penstock 2nd horizontal section ............................................................................. 26

Figure 40. Drilling work .......................................................................................................... 26

Figure 41. Penstock tunnel second horizontal section. ............................................................ 26

Figure 42. Penstock progress at 3rd horizontal sections upstream side. .................................. 26

Figure 43. Progress of Adit 1. .................................................................................................. 27

Figure 44. Adit 1 Portal. ......................................................................................................... 27

Figure 45. Breakthrough of Adit tunnel 1. ............................................................................... 27

Figure 46. Adit 2.1 and penstock tunnel junction. ................................................................... 27

Figure 47. Progress of Adit 2.2. ............................................................................................... 28

Figure 48. Adit 2.2 Portal area. ................................................................................................ 28

Figure 49. Lattice girder installation at Adit tunnel 2.2. .......................................................... 28

Figure 50. Progress at Adit 4. .................................................................................................. 28

Figure 51. Steel plate rolling machine at site ........................................................................... 29

Figure 52. Steel lining work at gravel flushing area. ............................................................... 29


September 2019 v

Figure 53. Radial gate frame and steel lining at undersluice area. .......................................... 29

Figure 54. Gate embedded part at bedload sluice. ................................................................... 29

Figure 55. Site security. ........................................................................................................... 32

Figure 56. New batching plant at headworks........................................................................... 32

Figure 57. New boomer at site. ................................................................................................ 32

Figure 58. Steel ribs fabrication at site. ................................................................................... 32

Figure 59. Rainfall measuring device at headworks area. ....................................................... 32

Figure 60. Concrete Cube curing. ............................................................................................ 32

Figure 61. View of powerhouse camp area. ........................................................................... 33

Figure 62. Hydromechanical yard ............................................................................................ 33

Figure 63. Headworks area. ..................................................................................................... 33

Figure 64. Gravel flushing pipe delivered at site. .................................................................... 33

Figure 65. Rebar work at settling basin. .................................................................................. 33

Figure 66. Concreting work at settling basin. .......................................................................... 33

Figure 67. Haggloader working at tunnel. ............................................................................... 34

Figure 68. Concreting work at settling basin. .......................................................................... 34

Figure 69. Crusher at powerhouse area.................................................................................... 34

Figure 70. Parts of Raise boring machine delivered at site. ..................................................... 34

Figure 71. Technical team during site visit. ............................................................................. 34

Figure 72. Team of technical persons during site visit. ........................................................... 34


September 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 June 2019. ........................................ 9

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

Table 7. Personnel of Employers Representative 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 ......................................................................... 31


September 2019 vii

Abbreviation and Acronyms

CMC Cooperativa Muratori & Cementisti

DoED Department of Electricity Development

DoF Department of Forest

DPR Detail Project Report

EIA Environmental Impact Assessment

El. Elevation

GoN Government of Nepal

GWh Gigawatt hour

HCEL Hydro-Consult Engineering Limited

HEP Hydroelectric Project

HRT Headrace Tunnel

HVPL Hydro Venture Private Limited

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

VDC Village Development Committee


September 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. Min Raj Kandel Director Mr. Paritosh Paudyal Director Mr. Mahendra Kumar Giri Director Mr. Bhoj Bahadur Shah Director Mr. Mukti Ram Pandey Director


September 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


September 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 Project was identified by Hydro Venture Pvt. Ltd (HVPL) in 2008. 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, Hydro Venture applied for the generation license with the DoED and presented among the concerned officials. DoED accordingly awarded the Generation License to HVPL 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 between HVPL and 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. HVPL was involved in acquisition of private land and development of infrastructures like access road and camp facilities of the Project till 23rd Chaitra 2073. After acquiring Hydro Venture Private Limited by Sahas Urja Limited (SUL), Sahas Urja Ltd is carrying out the infrastructure development works.

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


September 2019 4

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.

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


September 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


September 2019 6

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 2.2 275 m Adit 4 289 m With Finished Inverted D Dimensions 4.0 m wide × 4.0 m high

Surge Tunnel 375.00 m


September 2019 7

n. Penstock pipes

Horizontal section 1 220 m

Drop Shaft 1 189 m deep

Horizontal section 2 538.70 m long

Drop Shaft 2 252.70 m deep

Horizontal section 3 680 m long

Total length to bifurcation 1880.22 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 44 mm

o. Powerhouse

Type Surface

Dimensions 60 m Long × 16.2 m Wide × 18 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


September 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.


September 2019 9

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 August, 2019.

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

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

2. Physical modeling and Headworks modification. Mar. 2018

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

4. Vocational Training to the local People. Apr. 2018

5. Inlet Portal Preparation work. May 2018

6. Adit 2.1 Portal Preparation. May 2018

7. HM tripartite agreement July.2018

8. Contract Termination with EPC contractor CMC Dec. 2018

9. IEE for Transmission line Approved. Feb. 2019


September 2019 10

SN Completed Activities Dates 10. Contract agreement with CE Construction for construction of civil works. Feb. 2019

11. Mobilization of Civil contractor at site. Feb. 2019

12. Mobilization of Hydromechanical contractor at site. Jan. 2019

13. 1st Stage river Diversion work Completed Mar. 2019

14. Excavation for bedload sluice, undersluice and Intake completed Apr. 2019

15. Crusher at headworks and powerhouse completed and commissioned. Apr. 2019

16. Contract of S4 system for sediment flushing of Settling Basin‐Completed. May 2019

17. Adit 2.2 Portal preparation completed. May 2019

18. Portal for 2nd horizontal section for penstock tunnel. May 2019

19. Adit 1 Tunnel excavation work completed. Jun. 2019

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

21. Penstock Tunnel 1st horizontal section completed. Jun 2019

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

SN Recent Activities Dates 1. Concreting of Undersluice at headworks. Ongoing 2. Concreting of Intake and Gravel Trap. Ongoing 3. Concreting work at settling basin walls. Ongoing 4. Headrace Tunnel excavation from Inlet. Ongoing 5. Headrace Tunnel excavation from Outlet. Ongoing 6. Valve Chamber Tunnel excavation works. Ongoing 7. Penstock Tunnel 2nd horizontal section (from portal 3). Ongoing8. Penstock Tunnel 3rd horizontal section (from Adit 4). Ongoing9. Powerhouse excavation. Ongoing10. Hydromechanical Work at bedload sluice canal, steel lining and gate work. Ongoing


September 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.

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 two times. 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

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.


September 2019 12

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.

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

DPR report consists of detail design of transmission line components. 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. 35 Days public notice regarding the generation license has been published. Figure 10 shows the transmission line route with the position of tower in google map.


September 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.


September 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 Employer’s Representative at site

Currently there are 32 personnel at site. Table 7 shows the list of site personnel of Employers Representative.

Table 7. Personnel of Employers Representative at Site

S. No. Job Classification Number of personnel

1. Technical 24

2. Administrative / Account 2

3. Support Staff 6

Total 32


September 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 modal 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 9 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 10 12. Lab Technician 1 13. Health and Safety Officer 6 14. Blaster Welder, Plumber, Electrician, 33 15. Information Technician 1 16. Tradesman 100 17. Cooks and house keeper 20 18. Skilled and unskilled labor 343 19. Security Guard 25

Total 614


September 2019 16

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

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

The following figures shows contractor’s camp at different area, crusher plants and batching plant.

Crusher plant installation is complete at headworks and powerhouse area. Similarly, two batching plant has been installed at headworks area one batching plant of 18m3/h capacity is installed at surge tunnel area and other batching plant is at powerhouse area.


September 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


September 2019 18

Civil Works

The civil works comprises of mainly 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 headings below:

5.3.1.1 Headworks

Before starting the headworks main components, the first stage is river diversion. This stage enables us to work in the River. Basically, River diversion occurs in two stage. However, the contractor has proposed a three-stage river diversion. The contractor has prioritized their headworks activities as numbered below in the Figure 17. Task numbered 1 and 2 base work are completed and preparation for base work of task 3 and 4 are ongoing.

Figure 17. Prioritized tasks at the headworks.


September 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 us to construct the undersluice, intake and bedload sluice in this dry season.

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

Cofferdam construction for 1st stage river diversion at headworks has been completed. The 1st stage headworks construction work is going on at site.

Weir, Bedload Sluice, Undersluice and Sluiceway canal

The diversion weir is a gravity weir of 31.8 m long crest with horizontal 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 1100 m3 of concreting work has been completed. Excavation of remaining part of bedload sluice is also going on.. Figure 19, Figure 20, Figure 21 and Figure 22 shows the progress of concreting works at bedload sluice and undersluice area.


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Figure 19. Rebar work at Gravel trap area. Figure 20. Rebar and form work in progress

Figure 21. Rebar and embedded part of gate at undersluice.

Figure 22. Bedload sluice

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.


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The Excavation work of intake is complete and currently the base work of intake and gravel trap is in progress. Similarly, the gravel flushing base work is complete and the vertical wall and steel lining work is going on. The figure below shows the progress of intake and gravel trap area.

Figure 23. Intake area. Figure 24. Gravel flushing area work progress.

Approach Canal

Immediately after gravel trap, three individual approach culverts having different length, horizontal 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. Currently the concreting of different panels of settling basin is going on. Base work of all four panel has been completed. The vertical shear wall concreting is going on. Till the end of reporting period about 30,000 m3 earthwork have been excavated and 3000 m3 concreting work has been completed. The figure below shows the excavation work in settling basin area.


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Figure 25. PCC of settling basin. Figure 26. Rebar work at settling basin.

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


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of the river. The design of powerhouse is complete and currently the excavation work and slope stabilization work are going on at site. Figure below shows the excavation area and slope protection work.

Figure 29. Excavation at powerhouse area. Figure 30. Shotcrete work for slope stabilization 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.

March. April May June July August

31

228 235

359299

432

MONTHLY PROGRESS


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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 673 m tunnel excavation has been completed, previous contractor had excavated 173 m and CE had completed 506 m of tunnel from the inlet face. Temporary support and permanent support are also in progress where necessary. Similarly, after the completion of 1st horizontal section of penstock alignment headrace tunnel excavation is going on from Adit 2.1. Till the end of reporting period 150 m tunnel excavation has been complete from the outlet face. The figure below shows the tunnel progress of HRT.

Figure 32. Progress chart of headrace tunnel.

Figure 33. Holes Drilled at HRT.

Figure 34. Niche at Headrace tunnel.


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Figure 35.Junction of Adit 2.2 and headrace tunnel alignment. 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 1880 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 538.69 m length, and second vertical drop of 252.70 m length. After second vertical drop, it runs through an inclined portion of 680 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

Figure 37. Support work at penstock 1st horizontal section.

Figure 38. 1st horizontal section.


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One portal is prepared at the start of 2nd vertical shaft, this portal facilitates the excavation of inclined section of penstock alignment and vertical shaft 2. Due to poor geology the excavation of tunnel is going on in slow speed. Till the end of reporting period 147 m tunnel excavation has been completed from that face. The figure below shows the Progress of tunnel work and the tunnel excavation work.

Figure 39. Penstock 2nd horizontal section

Figure 40. Drilling work Figure 41. Penstock tunnel second horizontal section.

After the completion of Adit 4 penstock section upstream of Adit junction has been in progress. Till the end of the reporting period 92 m penstock tunnel has been completed at third inclined section.

Figure 42. Penstock progress at 3rd horizontal sections upstream side.

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


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tunnel work in later days. Adit 1 excavation has been complete, the breakthrough was complete on June 2019. Figure below shows the view of Adit 1.

Figure 43. Progress of Adit 1.

Figure 44. Adit 1 Portal.

Figure 45. Breakthrough of Adit tunnel 1.

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 horizontal section of penstock alignment excavation upstream of Adit 2.1 is complete and headrace tunnel excavation is going on.

Figure 46. Adit 2.1 and penstock tunnel junction.


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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 275 m and till the end of reporting period 233 m tunnel excavation has been completed. Figure below shows the progress, portal work and the tunnel excavation work of Adit tunnel.

Figure 47. Progress of Adit 2.2.

Figure 48. Adit 2.2 Portal area.

Figure 49. Lattice girder installation 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 horizontal section u/s side is continuing.

Figure 50. Progress at Adit 4.


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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 horizontal 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 horizontal 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 675 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 horizontal part has the support piers.

Machhapuchhre Metal and Machinery Works Pvt. Ltd (Hydromechanical Contractor 3MW) is in the stage of mobilization at site. 3MW contractor is currently preparing the yard. Steel lining works and gate installation at undersluice and bed load sluice at headworks area is ongoing.

Figure 51. Steel plate rolling machine at site

Figure 52. Steel lining work at gravel flushing area.

Figure 53. Radial gate frame and steel lining at undersluice.

Figure 54. Gate embedded part at bedload sluice.


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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 30400 KW each.


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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 VDC.

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

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

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 55. Site security. Figure 56. New batching plant at headworks.

Figure 57. New boomer at site. Figure 58. Steel ribs fabrication at site.

Figure 59. Rainfall measuring device at headworks area. Figure 60. Concrete Cube curing.


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Figure 61. View of powerhouse camp area.

Figure 62. Hydromechanical yard

Figure 63. Headworks area.

Figure 64. Gravel flushing pipe delivered at site.

Figure 65. Rebar work at settling basin.

Figure 66. Concreting work at settling basin.


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Figure 67. Haggloader working at tunnel. Figure 68. Concreting work at settling basin.

Figure 69. Crusher at powerhouse area. Figure 70. Parts of Raise boring machine delivered at site.

Figure 71. Technical team during site visit.

Figure 72. Team of technical persons during site visit.

Documents

SOLU KHOLA (DUDH KOSHI) HYDROELECTRIC PROJECT (86MW) · Figure 6 Penstock plan and profile ... Figure 37. Support work at penstock section. ... Similarly, the nearest road head from