SOLU KHOLA (DUDH KOSHI) HYDROELECTRIC PROJECT (86MW)sahasurja.com/wp-content/uploads/2019/05/W010-2.pdf · 2019. 5. 22. · awarded the Generation License to HVPL on 2071-06-02 (18

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

Progress Report # W010

Sahas Urja Ltd. (SUL)

Hattisar, Kathmandu, Nepal

May 2019

Sahas Urja Limited Progress Report of SKDKHEP # W010

May 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 .................................................................................. 10

Chapter 3 Pre-construction and Infrastructure Works ............................................................. 12

Land Acquisition ........................................................................................................... 12

Access Road and Bridge ............................................................................................... 12

Camp and Other Facilities ............................................................................................ 14

Transmission Line ......................................................................................................... 15

Physical Modelling ....................................................................................................... 16

Chapter 4 Employer’s Representative/Engineer Mobilization ................................................ 17

Chapter 5 Civil Construction Works ........................................................................................ 18

Contractor’s Mobilization ............................................................................................. 18

Explosive....................................................................................................................... 21

Civil Works ................................................................................................................... 22

5.3.1 Surface Structures .............................................................................................. 22

5.3.1.1 Headworks ...................................................................................................... 22


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5.3.1.2 Powerhouse .................................................................................................... 25

5.3.2 Underground Structures ..................................................................................... 26

5.3.2.1 Headrace Tunnel ............................................................................................ 26

5.3.2.2 Adit Tunnels ................................................................................................... 27

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

ii) Adit 2.1 .................................................................................................................. 28

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

iv) Adit 3 ..................................................................................................................... 29

v) Adit 4 ..................................................................................................................... 29

Chapter 6 Hydro-Mechanical and Electrical Works ................................................................ 31

Hydro-Mechanical Works ............................................................................................. 31

Electro-Mechanical Works ........................................................................................... 32

Chapter 7 Social Works ........................................................................................................... 33

Annex:1 Some Additional Photos .............................................................................................. 1


May 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 ................................................................................... 12

Figure 8. Road A section. ........................................................................................................ 13

Figure 9. Road B. ..................................................................................................................... 13

Figure 10. Road C .................................................................................................................... 13

Figure 11 Road D ..................................................................................................................... 13

Figure 12. Road E .................................................................................................................... 14

Figure 13. Road F .................................................................................................................... 14

Figure 14. Bailey Bridge 1. ...................................................................................................... 14

Figure 15. Bailey Bridge 2. ...................................................................................................... 14

Figure 16. Headworks Camp Area........................................................................................... 15

Figure 17. Powerhouse camp area. .......................................................................................... 15

Figure 18: Transmission line route in Google Image .............................................................. 15

Figure 19. Modified headworks design ................................................................................... 16

Figure 20. Performance of headworks ..................................................................................... 16

Figure 21. Organization chart of Employer’s Representative at site ....................................... 17

Figure 22. Contractor's camp at headworks ............................................................................. 20

Figure 23. Contractors labor camp at headworks. ................................................................... 20

Figure 24. Contactors camp at powerhouse. ............................................................................ 20

Figure 25. Batching plant at Polmu area. ................................................................................. 20


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Figure 26. Crusher plant at headworks area............................................................................. 20

Figure 27. Crusher at headworks in progress........................................................................... 20

Figure 28. Crusher at Powerhouse area. .................................................................................. 21

Figure 29. Crusher installation at powerhouse area. ................................................................ 21

Figure 30. Army camp near Surge Tunnel area ....................................................................... 21

Figure 31. Schematic drawing of 1st phase river diversion. .................................................... 22

Figure 32.1st stage River Diversion work ............................................................................... 23

Figure 33. Coffer dam construction for river diversion. .......................................................... 23

Figure 34. Excavation work of undersluice area. .................................................................... 23

Figure 35. Excavation work. .................................................................................................... 23

Figure 36. Construction work at sluiceway canal area. ........................................................... 24

Figure 37. Concrete work at sluiceway canal area. ................................................................. 24

Figure 38. Excavation in intake area. ....................................................................................... 24

Figure 39. Excavation work at Settling basin area. ................................................................. 25

Figure 40. Excavation to certain level of settling basin completed. ........................................ 25

Figure 41. Slope cutting at powerhouse area. .......................................................................... 26

Figure 42. Slope cutting at progress. ....................................................................................... 26

Figure 43. Inlet portal area. ...................................................................................................... 27

Figure 44. Junction of Adit 1 and Headrace tunnel. ................................................................ 27

Figure 45. Drilling work at tunnel face. ................................................................................... 27

Figure 46. Inspection of tunnel work. ...................................................................................... 27

Figure 47. Portal preparation of Adit 1. ................................................................................... 28

Figure 48. Junction of HRT and Adit 1. .................................................................................. 28

Figure 49. Penstock tunnel from Adit 2.1 Upstream ............................................................... 28

Figure 50. Junction of Penstock tunnel and Adit 2.1 ............................................................... 28

Figure 51. Adit 2.2 area. .......................................................................................................... 29

Figure 52. Portal area of Adit 2.2. ........................................................................................... 29


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Figure 53. Adit 3 portal preparation. ....................................................................................... 29

Figure 54. Adit 4 view. ............................................................................................................ 30

Figure 55. Work progress at adit 4 area. .................................................................................. 30

Figure 56. Tunnel work examination by team of Engineer. .................................................... 30

Figure 57. Support work at Adit 4. .......................................................................................... 30

Figure 58. View of hydromechanical yard. ............................................................................. 31

Figure 59 Foundation work of yard. ........................................................................................ 31

Figure 60. Road extension work at Ramite .............................................................................. 33

Figure 61 Social Road upgradation work. ............................................................................... 33

Figure 62. Adit 1 area ................................................................................................................ 1

Figure 63. Batching plant at headworks .................................................................................... 1

Figure 64. Testing laboratory. .................................................................................................... 1

Figure 65. Batching plant at surge shaft area. ............................................................................ 1

Figure 66. Crusher at headworks. .............................................................................................. 1

Figure 67 Crusher at Powerhouse area. ..................................................................................... 1

Figure 68. formwork at headworks undersluice area. ................................................................ 2

Figure 69. work in progress at headworks ................................................................................. 2

Figure 70. Adit 2.2 portal preparation. ...................................................................................... 2

Figure 71. Adit 3 Portal area. ..................................................................................................... 2

Figure 72. Hydromechanical yard preparation. ......................................................................... 2

Figure 73. Adit 4 view. .............................................................................................................. 2

Figure 74. Support work at tunnel. ............................................................................................ 3

Figure 75. Headrace tunnel progress. ........................................................................................ 3

Figure 76. Site visit by the key personnel’s of Client, consultant and contractor ..................... 3

Figure 77. Site investigation work by technical team. ............................................................... 3

Figure 78. Tunnel inspection by tunnel experts. ........................................................................ 3

Figure 79. Monthly coordination meeting at site office. ........................................................... 3


May 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, 2018 ................................. 10

Table 6. Summary of recent activities completed from September 2018 to April 2019 ......... 11

Table 7. List of Access Roads of Project. ................................................................................ 13

Table 8. Personnel of Employers Representative at Site ......................................................... 17

Table 9. List of manpower at site. ............................................................................................ 18

Table 10. Major Plant and equipment and vehicles of civil contractor at site. ........................ 19

Table 11. List of Road constructed for society ........................................................................ 33


May 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


May 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


May 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


May 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 branches towards SKDKHEP headworks site. The Headworks site is about 257 km


May 2019 4

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


May 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


May 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 4,503.0 m Adit 1 93 m

Adit 2.1 27 m

Adit 2.2 280 m With Finished Inverted D Dimensions 3.8 m wide × 3.8 m high Adit 4 300 m


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

Surge Tunnel 375.00 m

n. Penstock pipes

Horizontal section 1 240 m

Drop Shaft 1 185 m deep

Horizontal section 2 485 m long

Drop Shaft 2 255 m deep

Horizontal section 3 685 m long

Total length to trifurcation 1850.0 m

Pipe Steel Grade 350MPa and 460 MPa

Internal Diameter and Length Diameter varies from 2.50 m to 2.10 m to 1.7m and 1.2m.

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

12.5 km long 132 kV

r. Switchyard 60 m long × 50 m wide


May 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.


May 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 As per PPA 12/10/2076 As per Amendment 6/10/2077

3 FINANCIAL CLOSURE DATE As required by PPA 6/1/2072 Revised Date 6/1/2073 4 ACTUAL FINANCIAL CLOSURE DATE 4/20/2073


May 2019 10

S. No. DESCRIPTION DATE

5 GENERATION LICENCE Received Date 6/2/2071 Transfer Date to Sahas Urja Limited 2/1/2074 6 REQUIRED COD 6/10/2077

7 CONNECTION POINT, VOLTAGE LEVEL Tingla, Lammane Substation, 132 KV Double

circuit

Summary of activities performed

Following tables presents the key activities and progress of the project from the date of survey license to April, 2019.

Table 5. Summary of activities completed till the end of March, 2019

SN Activities Dates

1. Detail Design Report submitted by Hydro Consult Engineering Ltd. (HCEL)

September 2017

2. Land purchase limit- approval obtained. September 2017

3. Contract agreement with the Department of Forest (DoF) regarding tree cutting and land use.

November 2017

4. Contract with the Consortium of Hydro-Consult Engineering Limited and Fichtner GmbH & Co.KG as Employer’s Representative/ Consultant.

December 2017

5. Mobilization of Employer’s Representative/Engineer at site. February 2018

6. Physical modeling and Headworks modification. March 2018

7. Construction of bunker for Army camp and explosive storage. April 2018

8. Vocational Training to the local People. April 2018

9. Inlet Portal Preparation work. May 2018

10. Adit 2.1 Portal Preparation. May 2018

11. Tripartite agreement among SUL, CMC and Machhapuchhre Metal and Machinery Works Pvt. Ltd for Hydromechanical work.

July 2018

12. IEE Final report Submission to DoED after incorporation of comments August 2018

13. Units (Technical Consultant) site visit November 2018

14. Contract Termination with EPC contractor CMC December 2018

15. IEE for Transmission line Approved. February 2019

16. Contract agreement with CE Construction for construction of civil works. February 2019

17. Mobilization of Civil contractor at site. February 2019

18. Mobilization of Hydromechanical contractor at site. January 2019

19. 1st Stage river Diversion work. March 2019


May 2019 11

Table 6. Summary of recent activities completed till the end of April 2019

S. N. Activities Dates

1. Excavation for undersluice, Intake and some portion of weir completed

April 2019

2. Crusher at headworks and powerhouse completed and commissioned.

April 2019

3. Base concreting of bed load sluice at headworks. Ongoing 4. Headrace tunnel excavation from Inlet. Ongoing

5. Adit 1 tunnel excavation and support work. Ongoing

6. Adit 2.2 Portal preparation work. Ongoing 7. Penstock alignment tunnel excavation from Adit 2.1. Ongoing 8. Adit 3 Portal excavation work. Ongoing 9. Adit 4 tunnel excavation and support work. Ongoing


May 2019 12

Chapter 3 Pre-construction and Infrastructure Works

This chapter covers the works required to be completed 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 access road from headworks to powerhouse is about 21.71 km. and crosses the Solu River two times. The road length from Ramite (nearest road head in Okhaldhunga - Salleri highway) to headworks is 9 km. Opening of track connecting headworks to Powerhouse is complete. Details of access road track constructed is listed in Table 7. At the same time, upgradation of access road is completed however due to land slide certain section needs periodic repair, maintenance and debris clearance.

Figure 7. Project Access Road network


May 2019 13

Table 7. List of Access Roads of Project.

S. N. Road Name From-To Total Length (km)

1 Road A Zero (Bhadaure)- Bridge 1 at Headworks 2.5002 Road B Junction of Road A and B- Bridge 2 1.5403 Road C Bridge 2- Thulodhunga 1.9464 Road D Thulodhunga – Panchan Bhanjyang 6.5025 Road E Panchan Bhanjyang – Bhorleni Site camp 2.1206 Road F Bhorleni site camp- Powerhouse 6.8037 Road G Bridge 1- Headworks 0.300

Total 21.711

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 Road E will be used to access Maikhubesi i.e. Powerhouse location. The following figures shows the road sections of access road.

Figure 8. Road A section. Figure 9. Road B.

Figure 10. Road C

Figure 11 Road D


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Figure 12. Road E

Figure 13. Road F

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. The Figure 14 and Figure 15 shows the two Bailey bridge installed at site.

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.

Figure 14. Bailey Bridge 1. Figure 15. Bailey Bridge 2.


May 2019 15

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. Figure 16, Figure 17 shows the camp facilities at headworks and powerhouse area.

Figure 16. Headworks Camp Area.

Figure 17. 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. Figure 18 shows the transmission line route with the position of tower in google map.

Figure 18: Transmission line route in Google Image


May 2019 16

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 of headworks is being done accordingly. The figures below show the modified headworks model.

Figure 19. Modified headworks design

Figure 20. Performance of headworks


May 2019 17

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 already at site. As the modality of the Contract has been changed from turnkey to quantity based, the role of Employer’s Representative shall be changed to the role of Engineer as per the FIDIC and the same is in process.

Figure 21. Organization chart of Employer’s Representative at site

Currently there are 30 personnel at site. Table 8 shows the list of site personnel of Employers Representative.

Table 8. Personnel of Employers Representative at Site

S. No. Job Classification Number of personnel

1. Technical 19

2. Administrative / Account 2

3. Support Staff 9

Total 30


May 2019 18

Chapter 5 Civil Construction Works

The EPC contract for the construction activities comprising of Civil, Hydro-mechanical and Electro-mechanical Works was awarded on 9th June 2017 to Cooperativa Muratori & Cementisti (CMC) Di. Ravenna. However, EPC contractor totally abandoned the work and left site in the month of December 2018. Hence, the contract was terminated with CMC on 30th December 2018.

In order to continue the construction works, SUL awarded the Contract to CE Construction Pvt. Ltd. on 11th February 2019 with the commencement date as 25th Feb 2019. However, the modality of the contract changed from Turnkey to 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 has been mobilized at site. Previous Contractor had built camps at

headworks and powerhouse areas. CE construction is using the same camp facilities with modifications as per their requirements. Mobilization of contractor is nearly complete. Working platform preparation at all the tunnel faces is undergoing. Table 9 and Table 10 below shows the manpower, plant and equipment of the contractor at site.

Table 9. List of manpower at site.

S.N. Designation Number Remarks 1. Project Manager 1 2. Assistant Project Manager 4 3. Civil Engineer 7 4. Electrical Engineer 2 5. Mechanical In-charge 2 6. Supervisor, foreman and mechanic 22 7. Surveyor 6 8. Geologist 4 9. Public Relation Officer 3 10. Accountant, procurement, Store keeper 9 11. Draftsman, overseer, Sub-overseer 6 12. Lab Technician 1 13. Health and Safety Officer 5 14. Blaster Welder, Plumber, Electrician 37 15. Information Technician 1 16. Operator and Drivers 46 17. Helpers 24 18. Cooks and house keeper 11 19. Skilled and unskilled labor 148 20. Security Guard 17

Total 356


May 2019 19

Table 10. Major Plant and equipment and vehicles of civil contractor at site.

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

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, one batching plant has been installed at headworks area and other batching plant of 18m3/h capacity is installed at surge tunnel area.


May 2019 20

Figure 22. Contractor's camp at headworks

Figure 23. Contractors labor camp at headworks.

Figure 24. Contactors camp at powerhouse.

Figure 25. Batching plant at Polmu area.

Figure 26. Crusher plant at headworks area.

Figure 27. Crusher at headworks in progress.


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Figure 28. Crusher at Powerhouse area.

Figure 29. Crusher installation 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 30.

Figure 30. Army camp near Surge Tunnel area


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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, 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.

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 part of weir in this dry season.

Figure 31. Schematic drawing of 1st phase river diversion.

Cofferdam construction for 1st stage river diversion at headworks has been completed. Currently the excavation for the foundation of undersluice, intake and certain part of weir and stilling basin is in progress. The figure below shows the river diversion and cofferdam construction.


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Figure 32.1st stage River Diversion work Figure 33. Coffer dam construction for river diversion.

Weir, 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 one 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.

Excavation for sluiceway canal, stilling basin, undersluice and weir determined for first stage has been completed. The total excavation till date is 16070.18 m3. The concreting work including rebar and formwork of sluiceway canal is started. The Figure 34 and Figure 35 below shows the excavation works at headworks area whereas Figure 36 and Figure 37 illustrates the progress in the concreting works.

Figure 34. Excavation work of undersluice area.

Figure 35. Excavation work.


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Figure 36. Construction work at sluiceway canal area. Figure 37. Concrete work at sluiceway canal area.

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 in progress. The figure below shows the excavation work of intake area.

Figure 38. Excavation in intake area.


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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 is also continuing the earth work at settling basin. The figure below shows the excavation work in settling basin area.

Figure 39. Excavation work at Settling basin area. Figure 40. Excavation to certain level of settling basin completed.

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 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.


May 2019 26

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.

Site clearance and earthwork in excavation has started at powerhouse area. Slope stabilization at upper slopes has been started. Excavation photos are shown in Figure 41 and Figure 42.

Figure 41. Slope cutting at powerhouse area.

Figure 42. Slope cutting at progress.

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 4503.0 m. An Adit tunnel of 93 m length is proposed 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.

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 4503m.

Inlet portal preparation was completed in the month of May 2018. After the portal work Headrace tunnel

excavation using Boomer is in progress. Till the end of this reporting period 252 m of Headrace Tunnel has been excavated from the inlet face. Currently adit 1 tunnel is in progress from the junction. Temporary support and permanent support are also in progress where necessary, the figure below shows the tunnel progress of HRT.


May 2019 27

Figure 43. Inlet portal area. Figure 44. Junction of Adit 1 and Headrace tunnel.

Figure 45. Drilling work at tunnel face.

Figure 46. Inspection of tunnel work.

5.3.2.2 Adit Tunnels

i) Adit 1

Adit 1 is 93 m long and it meets the headrace tunnel at chainage of 0+154.00 m. The location of Adit 1 portal 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. The portal preparation work of Adit 1 is going on from outer face whereas, the Adit tunnel work is in progress from the junction with HRT. Till the reporting period 80 m tunnel excavation has been completed. Figure below shows the Adit 1 work.


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Figure 47. Portal preparation of Adit 1. Figure 48. Junction of HRT and Adit 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 meets the first horizontal section of penstock tunnel at around 0+182m chainage from the surge tunnel. Adit 2.1 is 27 m long and fully excavated by previous contractor. Currently penstock alignment excavation upstream of Adit 2.1 is in good progress from this face, till the end of reporting period about 130 m tunnel excavation has been completed. Figure below shows the Adit tunnel 2.1.

Figure 49. Penstock tunnel from Adit 2.1 Upstream

Figure 50. Junction of Penstock tunnel and Adit 2.1

iii) Adit 2.2

The new location of Adit 2.2 lies upstream of Adit-2.1. Adit 2.2 has been incorporated to expedite the headrace tunnel excavation. Portal preparation work is going on in the Adit 2.2 area. Figure below shows the slope protection work of portal.

HRT and Adit 1JunctionAdit 1 Portal


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Figure 51. Adit 2.2 area. Figure 52. Portal area of Adit 2.2.

iv) Adit 3

Adit 3 facilitates the excavation of inclined section of penstock alignment and vertical shaft 2. The location of Adit 3 is fixed and portal preparation is going on. The figure below shows the portal preparation of Adit 3.

Figure 53. Adit 3 portal preparation.

v) Adit 4

Adit 4 located near powerhouse is of length 300 m and of internal size 3.8 m inverted D shape. Portal preparation is completed and currently excavating the tunnel of Adit 4. Till the end of reporting period 180 m tunnel excavation was complete. Figures below shows the tunnel work at Adit 4.


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Figure 54. Adit 4 view. Figure 55. Work progress at adit 4 area.

Figure 56. Tunnel work examination by team of Engineer. Figure 57. Support work at Adit 4.


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Chapter 6 Hydro-Mechanical and Electrical Works

Hydro-Mechanical Works

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 3.8 m and 3.5 m respectively. The penstock pipe diameter varies from 2.5 m to 2.1 m and finally 1.2 m at the portion of main inlet valve. Likewise, the thickness of the penstock pipe varies from 10 mm to 44 mm. The penstock pipe starts after the surge tunnel with an invert level of 1229.08 having horizontal portion of 240 m length and first vertical drop of 185 m length. Likewise, the pipe passes through the inclined portion of 485 m length, and second vertical drop of 255 m length. After second vertical drop, it runs through an inclined portion of 685 m length up to trifurcation. The penstock pipe has varying diameter with varying thickness. Altogether, the penstock alignment has four bends before trifurcation. The vertical part is penstock casing with concrete infill and the horizontal part has the support piers as shown in the drawings. There are three Adits: one at the location of first drop shaft from Adit 2.1, other at second drop shaft from Adit 3 and third from Adit 4 near the powerhouse site to ease the construction of the penstock pipe.

For the hydromechanical work the Contractor, Machhapuchhre Metal and Machinery Works Pvt. Ltd, is in the stage of mobilization at site. Hydromechanical contractor is currently preparing the yard and camp. The figure below is the yard preparation progress till this reporting period.

Figure 58. View of hydromechanical yard. Figure 59 Foundation work of yard.


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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 assuming the efficiency to be 91%.


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Chapter 7 Social Works

The project has been doing different social activities in project affected areas. One of the major social activity in this period was upgradation of village road from Ramite to Surge tank of LSHEP (2.5km) on the request of public. The upgradation of Ramite road is shown in Figure 60 and Figure 61. Beside that the maintenance of village road from Tumse to Panchan is being done. Village road at Maikhubesi to old suspension bridge was also upgraded on the request of local people. Similarly, new track of village road of about 1.6 KM length has been opened at Bhorleni on the request of local people. The recent activities on the different sections of the social road are listed in Table 11. The figures below illustrate the social road upgraded by the company.

Figure 60. Road extension work at Ramite

Figure 61 Social Road upgradation work.

Table 11. 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 maintenance

6. Village Road at Baspura 2 Widening and maintenance7. Village Road at Bhorleni 1.6 New Track opening

Similarly, a water tank of 1000 ltrs capacity has been constructed at Bhorleni on the request of local

people. Excavator and JCB has also been used for various social purpose at Panchan and Tingla area.

Except for road construction, SUL is also helping locals with temple construction. This company also provided computers to schools and provided stretchers to the then Panchan VDC.


May 2019 34

Similarly, water supply pipe has been supplied to different localities of the project area. Excavator has been supplied for land scaping work of different schools and the protection work of school and temples is being done time and again in project affected areas.

Vocational trainings of electrician and off-season vegetable farming was provided to the locals from 19th March 2018 to 18th April 2018. The training was held at two locations i.e. Salyan and Panchan. A total of 109 participants attended the training program.


May 2019 1

Annex:1 Some Additional Photos

Figure 62. Adit 1 area

Figure 63. Batching plant at headworks

Figure 64. Testing laboratory.

Figure 65. Batching plant at surge shaft area.

Figure 66. Crusher at headworks.

Figure 67 Crusher at Powerhouse area.


May 2019 2

Figure 68. formwork at headworks undersluice area. Figure 69. work in progress at headworks

Figure 70. Adit 2.2 portal preparation. Figure 71. Adit 3 Portal area.

Figure 72. Hydromechanical yard preparation. Figure 73. Adit 4 view.


May 2019 3

Figure 74. Support work at tunnel.

Figure 75. Headrace tunnel progress.

Figure 76. Site visit by the key personnel’s of Client, consultant and contractor Figure 77. Site investigation work by technical team.

Figure 78. Tunnel inspection by tunnel experts. Figure 79. Monthly coordination meeting at site office.

Documents

SOLU KHOLA (DUDH KOSHI) HYDROELECTRIC PROJECT (86MW)sahasurja.com/wp-content/uploads/2019/05/W010-2.pdf · 2019. 5. 22. · awarded the Generation License to HVPL on 2071-06-02 (18