02 Preface to TOC

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PREFACE

This project entitled as Pre-Feasibility Study of Super Chepe Hydropower

Projectis carried out as a final year project of Bachelors Degree in Civil Engineering

as per the syllabus of, Institute of Engineering, TRIBHUWAN UNIVERSITY. The

objective of this project is to make the students familiar with the real projects that

are carried out in the professional engineering practice. It develops confidence and

ability to transfer the theoretical knowledge gained during the engineering course in

real civil engineering field.

Ours is an exclusively hydropower project. But hydropower is a

multidisciplinary field i.e. a congregation of various subsidiary branches of

engineering; from structural engineering to advanced electronics on power system

mechanism. It requires equal effort of hydrologist, geologist, structural engineer,

mechanical engineer, electrical engineer, electronics engineer, e.t.c. Our project was

focused on the civil components .Fundamentally, our effort and time were utilized in

understanding the basic components of a hydropower project and their functions,

collection of hydrological and geographical data provided and their designprocedures based on various codes, manuals, aids, guidelines and our hydropower

coursework. Although we had access to various academic materials, we were not

completely able to utilize our resources to the optimum level due to the various

constraints.

Our project basically begun with the collection of hydrological and

metrological data from the DHM (Department of Hydrology and Meteorology) It also

included the site visit to the pre-defined location on the powerhouse and the area in

vicinity to our designated headworks site. Due to the weather condition and the

remoteness of the site, we couldnt visit the exact headworks location. The

Hydropower tour to a number of small hydropower projects in Sindhupalchowk

district helped a lot to visualise and familiarize with the various hydropower

components .This report has been prepared on an academic format with few

shortcomings. Any corrective suggestions and recommendation on the report, if any,would be overwhelmingly appreciated.


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ACKNOWLEDGEMENT

We would like to express our deepest appreciation to Khwopa College of

Engineering, Civil Department for giving us an opportunity to conduct our project on

Prefeasibility study on Hydropower Project.

We would like to thank our supervisor Er. Rajesh Sapkota for his exemplary

guidance, monitoring and constant encouragement throughout the course of the

project work scheduled for this semester.

A note of thanks goes to Er. Sujan Maka, Head of Department of our college,

for his full cooperation during our study for this semester and providing the constant

remainder to finish the work in time.

We would also like to take this opportunity to express our gratitude to the

Department of Hydrology and Meteorology (DHM) and their staff members for their

cooperation and providing us with the required hydrological data for our study.

And lastly, we cannot forget the help and cooperation provided by our

classmates and colleagues throughout our project.

Project Group Members

Abhusan Achhami (066BCE02)

Albert Dahal (066BCE05)

Bidhan Dahal (066BCE13)

Bikram Khayamali (066BCE15)

Nischal Dhakal (066BCE47)


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EXECUTIVE SUMMARY

As we know, the current energy crisis in Nepal, declared as state of

emergency by the Nepal Government, has been of severe concern .The current load

shedding problem in the country seems to be getting worse day by day. It has been a

major setback not only in the economic and industrial advancement of the country

but also a big blow to the day-to-day sustainable life of the common people. Due to

the vast potential that this particular sector carries in our country, our only window

of opportunity for energy production, sustainability and independence is

hydropower development.

Super-Chepe Small Hydropower Project is a high head run-off type project

with the design discharge 3.42 m3/s. The installed capacity is 17.05MW with two

units of each 8.524 MW. It has a gross head of 613.091 m. We have considered two

alignments for our project with different water conveyance system. Alignment 1

consisted of tunnel headrace conveyance system whereas Alignment 2 consisted of

combined conveyance system of tunnel and pipe. For Alignment 1, headrace tunnel

of 6995 m was used for free flow of water. For Alignment 2, a headrace tunnel of

2725 m was connected to a closed conduit pipe of 4370 m for conveyance of water.

The dry/wet season total energy productions for Alignment 1 and 2 are 9.89

GWh/69.92 GWh and 9.79 GWh/ 69.21 GWh respectively.

The project is primarily focused on preliminary design of civil structures and

its arrangement regarding their size with respect to the design parameters obtained

and the locality constraints. Due to the time constraint and the limited scope of our

project, Environmental Impact Assessment (EIA) and Sediment Analysis were not

conducted.


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TABLE OF CONTENTS

Copyright 2

Approval Page 3

Preface 4

Acknowledgements 5

Executive Summary 6

Table of Contents 7

List of Abbreviations and Symbols 12

Salient Features Of SCSHP 16

CHAPTER ONE: INTRODUCTION 19

1.1Background 191.1.1 History of Hydropower 191.1.2 Case for renewable and non-renewable energy 201.1.3 Hydropower in Nepal 211.1.4 Power situation in Nepal/Power Market Survey 221.1.5 Hydropower Potential of Nepal 251.1.6 Hydropower Generation 261.1.7 Challenges and Issues in power sector 261.1.8 Advantages of Hydropower over other sources of energy 281.1.9 Justification of role of small hydropower in Nepal 291.1.10 Legal Provision for investment 30

1.2General Site Description 331.2.1 Location of the site 331.2.2 Physical Features 341.2.3 Accessibility 34

CHAPTER TWO: HYDROMETEOROLOGICAL INVESTIGATION 35

2.1Introduction 352.2Objectives 352.3 Scope 352.4 Physiographic characteristics of Chepe khola Basin 36

2.4.1 Basin 362.4.2 Catchment characteristics 362.4.3 Geology 372.4.4 Geomorphology 372.4.5 River system and gradient 37


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2.5 Flow Analysis 382.5.1 Long term Flow Analysis 382.5.2 Flow Duration Curve 432.5.3 Flood Frequency Analysis 45

2.5.3.1 Needs and necessities of design flood analysis 462.5.4 Flood Estimation for different return periods 462.5.5 Construction Flood Analysis 502.5.6 Low Flow Analysis 51

2.5.6.1 WECS/DHM 522.5.6.2 Gumbel Analysis for low flow 53

2.5.7 Riparian Flow 542.5.8 Stage Discharge Curve(Rating Curve) 54

2.5.8.1Need of Rating Curve 55CHAPTER THREE: COMPONENTS OF HYDROPOWER 57

3.1 Weir and undersluice 57

3.1.1 General 57

3.1.2 Design consideration of diversion weir 58

3.1.3 Elevation of weir crest 58

3.1.4 Length of weir and undersluice 58

3.1.5 Shape of the spillway 59

3.1.6 Forces acting on the weir 60

3.1.6.1 Hydrostatic Pressure 603.1.6.2 Uplift Pressure 60

3.1.6.3 Silt Pressure 60

3.1.6.4 Weight of weir 61

3.1.7 Modes of failure and criteria for structural

stability of weir 61

3.1.7.1 Overturning about the toe 61

3.1.7.2 Compression or crushing 62

3.1.7.3 Sliding 62

3.1.8 Protection works for weir structure 62

3.2 Intake structure 63

3.2.1 General 63

3.2.2 Design considerations for intake structures 64

3.2.3 Protection works 65

3.3 Gravel Trap 65

3.3.1 General 65

3.3.2 Design considerations 65



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3.4 Settling Basin 66

3.4.1 General 66



3.5 Water conveyance system 683.5.1 General 68

3.5.2 Design aspects of conveyance system 68


3.6 Surge Tank 69


3.6.2 Protection measures 70

3.7 Penstock 70

3.7.1 General 70

3.7.2 Design criteria for Penstock 713.7.3 Optimization 72

3.7.4 Protection works for penstock 72

3.8 Anchor block and support piers 73

3.8.1 General 73

3.8.2 Design philosophy 73

3.8.3 Provision for support piers 74

3.8.4 Provision for expansion joints 74

3.8.5 Construction 74

3.9 Powerhouse 75

3.9.1 General 75

3.9.2 Components of power house 75

3.10 Tailrace 76

3.10.1 General 76

3.10.2 Design criteria 76

3.11 Electro-mechanical units 77

3.11.1 General 77

3.11.2 Turbine 77

3.11.2.1 Design Philosophy 78

3.11.3 Generator 79

3.11.4 Excitor 79

3.11.5 Ventilation, cooling and lubrication 80

3.11.6 Transformer 80

3.11.7 Control room equipment 81

3.11.8 Switchgear 81

3.12 Transmission line 81

3.12.1 General 81

3.12.2 Design Aspects of transmission line 82


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CHAPTER FOUR: POWER OUTPUT AND ENERGY GENERATION 83

4.1Power type 834.1.1 Firm power 834.1.2 Secondary power 834.1.3 Peak Power 83

4.2Types of head 834.2.1 Gross Head 834.2.2 Net Head 83

4.3Types of efficiency 844.3.1 Turbine efficiency 844.3.2 Transformer efficiency 844.3.3 Generator efficiency 844.3.4 Overall efficiency 84

4.4 Installed capacity of plant 844.5 Types of energy 85

4.5.1 Firm Energy 854.5.2 Secondary Energy 85

CHAPTER FIVE: COST ESTIMATION AND FINANCIAL ANALYSIS 86

5.1 Introduction 865.2 Unit Rate Analysis 865.3 Engineering and Management fees 87

5.4 Contingency Sums 87

5.5 VAT/Taxes and Duties 87

5.6 Project Cost Estimate 88

5.7 Economic and Financial Analysis 88

5.8 Project Evaluation 88

5.9 Project Benefits 895.10 Economic Analysis 89

CHAPTER SIX: ALTERNATIVE ANALYSIS 90

CHAPTER SEVEN: ENVIRONMENTAL IMPACT ASSESSMENT 91

7.1 Introduction 917.2 Objectives of EIA 917.3 Philosophy and Purpose behind EIA 927.4 Identification of Environmental Impacts 92

7.4.1 Physical Environmental Impacts 927.4.2 Biological Environmental Impacts 93


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7.4.3 Socio-economic Impacts 937.4.4 Cultural Environmental Impacts 94

7.5 Environmental Impact monitoring 947.5.1 Baseline monitoring 947.5.2 Impact monitoring 947.5.3 Compliance monitoring 94

7.6Impact mitigation measures 947.7Conclusion and recommendation of EIA study 95

CHAPTER EIGHT: PROJECT PLANNING AND SCHEDULING 96

8.1 Introduction 968.2 Planning 968.3 Phase of construction 978.4 Time management in project 978.5 Project scheduling 978.6 Planning and scheduling of SCSHP 98

CONCLUSION AND RECOMMENDATIONS 99

BIBLOIOGRAPHY 101

APPENDIX A (Hydrological Analysis) 103

APPENDIX B (Component Design & Calculations) 125

APPENDIX C (Cost Estimate) 190

APPENDIX D (Financial Analysis) 204APPENDIX E (Maps and Design Drawings) 201

APPENDIX F (Access Roads) 215

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02 Preface to TOC