CHELA HYDROELECTRICPROJECT (3 X 25...

PRELIMINARY FEASIBILITY REPORT CHELA HEP 75 MW

ADVETA POWER PRIVATE LIMITED

MALPUR, BADDI, DIST.-SOLAN, H.P.-173205 1

CHELA HYDROELECTRICPROJECT

(3 X 25 MW) DISTRICT: KURUNG KUMEY

ARUNACHAL PRADESH

PRELIMINARY FEASIBILITY REPORT

MARCH 2012




INDEX Table of Content CHAPTER Page No 1.0 EXECUTIVE SUMMARY, LOCATION AND VICINITY MAP 4 2.0 PROJECT BACKGROUND 17 3.0 PROJECT AREA 23 4.0 HYDROLOGY 25 5.0 TOPOGRAPHIC AND GEOTECHNICAL ASPECTS 29 6.0 CONCEPTUAL LAYOUT AND PLANNING 34 7.0 POWER POTENTIAL STUDIES 38 8.0 COST ESTIMATES 40 9.0 FINANCIAL ANALYSIS 46 10.0 RECOMMENDATIONS 50

Drawings and Photographs

1.0 General Layout Plan 2.0 Ground Photographs




CHAPTER 1

EXECUTIVE SUMMARY




CHAPTER 1

EXECUTIVE SUMMARY

1.0 INTRODUCTION

Number of Hydro power Projects have been identified in Arunachal Pradesh a list

of these projects is enclosed as Annexure-1.1. CHELA (KOLORIANG) HEP is

one of these projects and is proposed on Kurung River in KurungKumey district

of Arunachal Pradesh. The project envisages utilization of water of the Kurung

River, a tributary of Subansiri River, by constructing a 28m high barrage at El ±

870 m to divert the water to water conductor system. The water will be diverted

through a 8.6 km long, 5.0m diameter circular shape head race tunnel together

with 400 m long 5 meter diameter steel pipe at the crossing of HRT with Panyu

River to a surface power station located on the right bank of the Kurungriver at

about El± 750 m. The DC office and Block development office of Koloriang

Project area and Kurung basin is Koloriang. The nearest rail heads are at

Harmoti-Assam and North Lakhimpur (200 Km from Koloriang), the nearest

Airport/Helipadare at Lila Bari /Koloriang and the nearest sea port is in Calcutta in

West Bengal.

Available gross head for the project is 145 m. In order to utilize this head, the

installation of 75 MW Project with Francis turbines is proposed. The project will

be operated as a peaking station during lean season with diurnal storage.




1.1 PROJECT ACCESSIBILITY AND INFRASTRUCTURE

The project site is well approachable from Itanagar, the state capital of Arunachal

Pradesh and district head quarter of Papumpare. Project site is about384km

away from Itanagar and is accessed through Koloriang.

ACCESS – KOLORIANGProject has been planned as Run-of-the (ROR) Project ,

along the right bank of River Kurung, BRO road from Koloriang leads to Project

area towards left bank of river Kurung.

ROAD ROUTE DISTANCE

GUWAHATI TO ITANAGAR – 415km

ITANAGAR TO KOLORIANG – 380 km (HILLY)

KOLORIANG (DC Office) TO PROJECT SITE –4 km

NEAREST RAIL HEAD:

HARMATI – 205 kmfrom the Project site

NEAREST AIRPORT:

LILABARI Airport is about 415 KM from the project site.

HELIPAD – Available at KOLORIANG

1.2 PROJECT COMPONENTS

KOLORIANGHE project envisages construction of

A 28m high barrage having FRL at EL 870 m

A simple surge shaft of 12m diameter




Head race tunnel of 8.6 km long, 5.0 m finished diameter together with 5 meter

diameter steel pipe

1 no. pressure shaft with 4 m diameter and 300 m long which at the end

trifurcating into three unit Penstocks each of 3 m diameter and 15 m long near the

powerhouse

A surface powerhouse having an installation of three Francis turbines driven

generating units of 25 MW each

1.3 HYDROLOGY

Sample discharge measurements at proposed barrage site on Kurung River have

been carried out by M/s ADVETA Power Private Limited. Based on these

measurements, long term discharge data of nearby rivers likely 10 –daily average

discharge values have been arrived. These values have been used for carrying

out power potential studies. However, during preparation of Detailed Project

Report measurements of water flow in the river at proposed barrage site shall be

carried out covering at least two lean seasons. This data together along the data

of nearby other rivers/ streams shall be used to develop long terms discharge

series at proposed barrage site.

1.4 POWER POTENTIAL STUDIES

As mentioned in paragraph 1.4 above, likely 10-daily average discharge values in

a 90 % dependable year have been utilized for computing power potential of the

Project. With an installation of 75 MW, the annual gross energy generation works

out to 457.42 MU with corresponding Annual Plant Load Factor (PLF) of 69.62 %

1.5 ENVIRONMENTAL ASPECTS




The predominant land use in the vicinity of the project area is forest and a portion

of residential land. The proposed reservoir will not submerge any villages and the

entire submergence will be inside the valley. There are no sites or monuments of

archaeological or national importance or wild life sanctuaries which would be

affected by the project activities directly or indirectly.

1.6 BROAD ESTIMATES OF THE COST

The project is estimated to cost Rupees 543.31 crores including IDC, escalation

and FM charges etc. Break-up of preliminary cost estimate of the project is given

below:

Particulars Amount (Rs in crores)

Pre-operative Expenses 19.12

Civil Works 322.82

Electro-mechanical Works 93.50

Interest during construction (IDC) 69.42

Escalation 34.39

Financial Management Charges (FM charges) 3.80

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Total cost of project 543.31

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1.7 FINANCIAL ASPECTS

As indicated above, the KOLORIANGHE project with an estimated cost of Rs.

543.31crores (including escalation, IDC, FM charges) and design energy of

444.61 MU in a 90% dependable year. The project is likely to be commissioned in

next 7 years’ time including preparation of DPR, techno-economic clearance,

obtaining all required clearances, developing infrastructure, appointing

contractors etc. The tariff has been work out considering debt equity ratio of

70:30. 12% of energy will be given as free power to home state and 1% towards

LADA. The tariff at the power house bus bars for first year has been work out to

Rs 3.06 per kWh and levellised tariff as Rs2.65 per kWh.

1.8 CONCLUSION

CHELA (KOLORIANG) HE project involves simple civil works and can be

constructed in 4 years’ time. The project would yield design energy of 444.61 MU

at the power house bus bars in a 90% dependable year. The cost per MW

installed, work out to be Rs7.24crores. The preliminary feasibility report indicates

that the scheme merits consideration for taking up for detailed survey,

investigation and preparation of DPR and subsequently implementing the project.

The Salient features of the project are given in Annexure-1.2.




1.9 LIMITATIONS OF THE STUDY AND RECOMMENDATIONS

It is to be noted that the results of current study presented in this report are based

on very limited information and one site visit and verification of sample elevations

in the field by the topographical surveyor. Therefore, for preparation of Detailed

Project Report detailed study will be required which will include collection of all

available data, field survey by civil engineers, geologists, hydrologists,

measurement of discharge, geological and geo-technical investigations etc.




List of identified Hydro Power Projects Annexure- 1.1

Sl. No. Name of Schemes River Basin Probable Installed Capacity (in MW)

1. Siang Lower Dihang/Dibang 1700.00

2. Bharali Lift Dam-II Kameng 330.00

3. Hegio Subansiri 250.00

4. Bharali Lift Dam-I Kameng 240.00

5. Emini Dihang/Dibang 295.00

6. Amulin Dihang/Dibang 235.00

7. Agolin Dihang/Dibang 235.00

8. KapakLeyak Kameng 195.00

9. Rigong Dihang/Dibang 130.00

10. Badao Kameng 120.00

11. Pakke Kameng 120.00

12. Kurung Dam-II Subansiri 115.00

13. Seba Kameng 105.00

14. Yepin Dihang/Dibang 95.00

15. Milli Subansiri 75.00

16. Chela Subansiri 75.00

17. Par Subansiri 65.00

18. Pongging Dihang/Dibang 60.00

19. Tago-I Subansiri 55.00

20. Para Kameng 55.00

21. Sepla Kameng 46.00

22. Lachung Kameng 41.00

23. Sape Subansiri 38.00

24. Ralgam Lohil 32.00

25. Nyapin Subansiri 32.00

26. Gimiliang Lohit 31.00

27. Rebby Kameng 30.00

28. Chanda Kameng 110.00

29. TarangWarang Kameng 65.00

30. Hiya Subansiri 41.00

31. Tiding-I Lohit 31.00

32. Kimi Kameng 535.00

33. Tato-II Dihang/Dibang 360.00

34. Panchung Kameng 90.00

35. Dardu Subansiri 60.00

36. Hutong Lohit 950.00




37. KOLORIANG Subansiri 80.00

38. Oju-II Subansiri 2580.00

39. Atunli Dihang/Dibang 175.00

40. Naba Subansiri 1290.00

41. Emra-II Dihang/Dibang 870.00

42. Noa-Dehing Lohit 75.00

43. Tammu Subansiri 55.00

44. Etalin Dihang/Dibang 3045.00

45. Kalai Lohit 2550.00

46. Naying Dihang/Dibang 495.00

47. Kameng Kameng 1100.00

48. Oju-I Subansiri 1925.00

49. Niare Subansiri 1405.00

50. Bichom-II Kameng 205.00

51. Passar Kameng 32.00

52. Stang Middle Dihang/Dibang 700.00

53. Emra-I Dihang/Dibang 275.00

54. Minnying Dihang/Dibang 195.00

55. Elango Dihang/Dibang 180.00

56. Doimukh storage Subansiri 170.00

57. Mirak Dihang/Dibang 160.00

58. Tato-I Dihang/Dibang 80.00

59. Nazong Kameng 65.00

60. Pauk Dihang/Dibang 50.00

61. Satuk Kameng 47.00

62. Gameng Dihang/Dibang 37.00

63. Papu Kameng 160.00

64. Jaru Dihang/Dibang 60.00

65. Pichang Kameng 31.00

66. Subansirinadi stage-II Subansiri 180.00

67. Mathithing Kameng 40.00

68. Khultam Kameng 29.00

59. Talong Kameng 150.00

70 Utong Kameng 110.00

71. Dibbin Kameng 95.00

72. Jarong Dihang/Dibang 85.00

73. But Kameng 26.00

74. Hirong Dihang/Dibang 180.00

75. Malinya Dihang/Dibang 335.00

76. Heo Dihang/Dibang 90.00

77. Yangman Storage U/Brahmaputra 60.00




78. Tenga Kameng 275.00

79. Mithundon Dihang/Dibang 145.00

80. Dibang Dihang/Dibang 1000.00

81. Sissiri Dihang/Dibang 222.00

82. Subansiri Middle Subansiri 2000.00

83. Siang Upper Dihang/Dibang 11000.00

84. Bichom-I Kameng 190.00

85. Subansiri Upper Subansiri 2500.00

86. Kurung Dam-I Subansiri 200.00

87. Subansiri Lower Subansiri 2000.00

88. Demwe Lohit 3000.00

89. Tipang U/Brahmaputra 80.00

TOTAL

49126.00




ANNEXURE 1.2 SALIENT FEATURES

LOCATION

State : Arunachal Pradesh

District : KURUNG KUMEY

River : KURUNG

Co-ordinate

Barrage site : 27⁰56’42.73” N

93⁰09’38.10” E

Power House Site : 27⁰53’45.05” N

93⁰22’47.63” E

Reference SOI Topo-Sheet No : 83 E / 05

HYDROLOGY

Catchment Area (diversion site) : 1430 Km2

DIVERSION STRUCTURE

Type : Barrage Gated

Length of Barrage at Top : 100 m

Bed level at diversion site : El ±870 m

Top level of structure : El ±898 m

FRL : El ±895 m

MDDL : El ±893 m




WATER CONDUCTOR SYSTEM

DESILTING CHAMBER

Type : Hopper

Particle size to be removed : 0.2 mm and above

No. of Chambers : 4

HEAD RACE TUNNEL

No. : 0ne

Diameter : 5 m (finished Circular)

Length : 8.6 km

Design discharge : 67.86m3/s

Pressure Pipe (at crossing of

Stream Panyu and HRT)

No. : 1 (Steel Pipe)

Diameter : 5 m

Design Discharge : 67.86m3/s

Length : 400 m

SURGE SHAFT

Type : Pressurized Shaft

Size : Circular, 12 m diameter

PRESSURE SHAFT

Type & No : Circular and One No.

Diameter : 3 m

Main Penstock : 300 m long




Branches penstock : 3 nos., 10 m long each

POWER HOUSE

Type : Surface

Type of Turbine : Francis Turbine

Generating Unit : 3 X 25 MW

Gross Head : 145 m

Rated Net head : 130.5m

TAIL RACE

Tail Water Level : 750 m

POWER GENERATION

Installed capacity : 75 MW

Annual Design energy generation : 457.42 MU

in90% dependable year

COST ESTIMATE (AT PRICE LEVEL MARCH, 2012)

Gross Total Cost : 543.31 Crores

FINANCIAL ASPECT

Tariff in first year : Rupees 3.06per kWh

Levellised tariff : Rupees 2.65 per kWh




CHAPTER 2

BACKGROUND INFORMATION




CHAPTER 2

PROJECT BACKGROUND

2.1 General 2.1.1 Location of Project

The project is located on Kurung River in KukrungKumey district of Arunachal Pradesh. The district is divided into 12 circles namely Damain, Sarli, LongdingKolong, ParsiParlo, Tali, Koloriang, Sangram, Chambang, Gangte, Nyapin, Yangte, Palin. Locations of these circles are show in the map given below:

Kurung-Kumey District Map

The project falls in KOLORIANG circle (DC- Office) .KOLORIANGis the district Headquarter of Kurung-Kumey. Koloriang is set amid green mountain peaks, terrace hills, lush valleys and fast flowing rivers. The word KOLORIANG is derived from two words “kolo” and “Riang”.kolo means name of a person who believed to be owner of the entire area. His name kolodani and Riang means land. In the North it has Hamching and in south GiloDomcho&TagiRaktak. Both are the name of the Mountains. In West papi River and




in East Panyu River flows through KOLORIANG, which originates from Hamching. KOLORIANG is a beautiful valley surrounded by beautiful mountains, in winter it is covered by clouds and is situated near the bank of mighty Kurungriver. Its altitude is 1040 m form the sea level.

The KOLORIANG administrative Head Office was set up on 23, August 1959 by the then political Officer Sri B.S. Doughal. By the time a new township consist of DC Office and other Govt. and Political offices .Accommodations of staffs was build up which declared township by Sri B.K Nehru, the then His Excellency Governor of Assam and Nagaland on 23, October 1969.

The modern history of the area is in fact counted with the setup of administrative machinery since 1959 till today this administrative set up was meant by 3(three) IFAS,1 IPS, 4 IAS and host of APCS Officers of different category.

The KOLORIANG Sub-Division with HQ at KOLORIANG has declared as Sub-Division vide Govt. Order No.CS/(B) 45 /89 Dtd 0501/99. But it has start function in its twist term form 1997.

KOLORIANG Administrative Centre is one of the oldest Administrative set up of the then Subansiri District. At present the area and particularly the township area of KOLORIANG which has a land area of 5,39,672.50 Sq. Meters and also having sound infrastructure facilities which will help for further up gradation of the Administrative Structure. The area is also adequate potentiality for hydro-power generation, Horticulture development and Tourism.

2.1.2 Physical Feature & Climate in Project Area

Physical Features:

The KurungKumey district of Arunachal Pradesh is lying approximately between 91.20' to 55.40' East Longitude and 28.30' to 38.04' North Latitudes.

The district is surrounded by China in the north, East Kameng District in the west, Upper Subansiri District and Lower Subansiri District and in the southern boundary adjoins by Papum Pare District in the East of the Arunachal Pradesh.

The topography of the district is mostly mountainous a great part of its falls within the medium mountain Zone consisting peak & valleys.

The altitude of the district headquarterYangteis about 4300 feet.




Climate:

The district falls within 15' to 20' temperature zone often the temperature falls to -4° degree in winter.

The region is very cold during winter and very hot during summer.

Rainfall is very high among the other districts due to very hilly and high geographical terrain.The district is most of time covered by clouds.The area is windy in nature.

2.2 Kurung River

The river Kurung is one of the perennial rivers that originate in the Upper reaches of

Indian Territory bordering China in the north. The river is having gentle to moderate

gradient with a numbers of rapid in its course, however at most of the places the river is

having gentle slope. The river is fed by Himalayan glacier, small rivulets, streams and

monsoon rainfall. River Kurung is a major tributary of Subansiri River. The catchment

area of proposed diversion site at EL ± 1050 m is about 1194 km2. Nearest village is

Tyang.

2.2 TEMPORARY DIVERSION STRUCTURE

It has been assessed during site visit that the River can be diverted in two phases by

providing all surface structures such as upstream and downstream coffer dams and

diverting the river in its part course for construction of Barrage and power Intake

structures.

2.3 BARRAGE

The Project is envisaged to have a 28 meter high barrage from the river bed level at

about an EL± 750 m. The site has been selected in the valley which is narrow and

geologically suitable. The top length of barrage shall be about 80 m at EL±750 m with

FRL at EL± 895 m with a free board of 3m.




2.4 POWER HOUSE

A surface power has been proposed based on field study with TWL at EL± 750 m.

Powerhouse location is about 12 km away from the barrage.

2.5 HEAD RACE TUNNEL

The water from the barrage shall be discharged through a circular finished 5.0 m diameter

headrace tunnel of 8.6 km length utilizing a gross head of ±145 m. The head race tunnel

shall be concrete lined. At the crossing of HRT alignment with stream Panyu , it is proposed to

lay steel pipe of 5 meter diameter.

2.6 SURGE SHAFT

A vertical surge shaft is envisaged with diameter 12m and a height of about 60m.

2.7 Penstock

Main penstock of 4 m diameter and 300 m length starting from the bottom of the surge

shaft followed by three unit penstock to serve three generating units has been planned.

2.8 Powerhouse and Tailrace

A surface powerhouse of 80 m 20 m and 35m height is proposed to be provided to house

three generating units each of 25 MW comprising Machine hall, control room, and service

bay. A tail race of suitable size and length shall be provided to discharge the water back

into the Kurung River.




2.9 Switchyard and Power Evacuation

A switchyard of suitable size adjacent to surface powerhouse shall be provided to evacuate

power at 132 kV voltage level by constructing 3km long 132 kV D/C transmission to the

proposed PGCIL sub-station at KOLORIANG.




CHAPTER 3

PROJECT AREA




CHAPTER 3

PROJECT AREA

The Project location falls in remote areas of the state of Arunachal Pradesh with

mainoccupation of the local populace being only agriculture.The main agriculture

produceof the area is paddy, besides maize, millet, wheat, oil seeds, pulses,

oranges,banana, pineapple, papaya, litchi, jack fruit etc. are also grown but in

comparativelyless quantity and there is no sufficient road communication to get any

commercialadvantages for utilizing these products for a livelihood. As such there is no

income tothe local populace from these agricultural products as it caters to the local needs

due towhich the people of entire area are below poverty line. The level of literacy is very

lowand unemployment rate is very high. Medical facilities are also very scanty.In the event

of taking off the KOLORIANG HE Project, it is envisaged that the economicdevelopment of

the entire area will be on threshold. The project shall bring socioeconomicdevelopment of

not only to the project area but also to the other areas, whichare located in near the dam

site areas. With the improved road communication, bettereducation and civic amenities

are bound to follow which will act as a catalyst fordevelopment of the entire area in all

spheres.

The project is located on the river Kurung which is a tributary of Subansiri River,the river is

of perennial nature.

The Kurung is a perennial river with its main source being snow melts of Himalayanglaciers

and small streams. Besides, the entire catchments receive moderate to heavymonsoon

showers from May to October each year. There is an appreciable drop indischarge during

the lean season, November to March every year.




CHAPTER 4

HYDROLOGY ‘




CHAPTER 4

HYDROLOGY

4.1 GENERAL

CHELA (KOLORIANG) HEP is a run-off–the river scheme, proposed on river Kurung, a

major tributary of Subansiri River, near Koloriang town, in Kurung Kumey district of

Arunachal Pradesh. The Barrage is proposed at about5 km u/s of Koloriang. During

preparation of Detailed Project Report hydrological investigations and analysis is carried

out with a view to:

Assess the availability of water for power generation by establishing along-term

series of average 10-daily discharges at the project site.

Estimate the spillway design flood.

Determine the capacity of the reservoir and the area of submergence at different

levels including FRL and MDDL.

Reservoir Sedimentation.

However, for preparation of preliminary feasibility report water availability has been

assesses based on sample discharge measurements, available long term discharge

data of other nearby rivers and streams, catchment area and catchment characteristics

etc.

4.2 RIVER SYSYTEM AND BASIN CHARACTERISTIC

The Kurung River area falls in Survey of India Topographical sheet No. 83E/01, 83E/05,

83 A/13, in district Kurung Kumey, is a perennial river with its main source being snow

melt of Himalayan glaciers, rainfall and small streams.

4.3 CATCHMENT AREA




Based on available SOI maps and Google maps, it has been worked out that the

catchment area of KOLORIANGHEP isapproximately 1430 km2. The catchment area

map as extracted on Google map is attached in Figure-4.1.

Fig-4.1

4.4 CLIMATE

The climate in the region is humid and moist. The area experience frequent

rainfall of varying intensity and duration. The average maximum temperature

around the project site is about 300C and average minimum temperature is about

- 4°C. The average rain fall varies from 250 to 300cm. About 80% of the annual




rainfall occurs during monsoon period of May to October and maximum

precipitation occurs during the month of June to August.

4.5 WATER AVAILABILITY

Water availability study has been carried out based on the following:

o Sample discharge measured in various months

o Local enquiry the villagers

o Catchment area and catchment Characteristics

o Long term discharge data of nearby major rivers

Likely ten daily average discharge values in a 90 % dependable year are

given in Annexure-4.1. These values are proposed to be utilized for power

potential studies of the project for Preliminary feasibility of the project.

4.6 RECOMMENDATION FOR FURTHER STUDY

During preparation of detailed project report, following is recommended to be

taken up for carrying out complete hydrological studies:

Establishing Gauge and Discharge site at proposed barrage site

Collection of all available discharge data of nearby streams and long term

discharge data of major rivers

Collection of rainfall, temperature, humidity data from India Meteorological

Department, New Delhi

Silt measurements in the river along with petro-graphical analysis of silt particles

Establishment of design flood for which barrage will have to be designed




CHAPTER 5

TOPOGRAPHIC

AND

GEOTECHNICAL ASPECTS




CHAPTER 5

TOPOGRAPHIC AND GEOTECHNICAL ASPECTS 5.1 GENERAL

This project area falls in Survey of India Topographical sheet No. 83 E/1. Based on

information available in topographic sheet and Google Earth, reconnaissance visit to the

project site was made by the team of civil engineers and surveyor of M/s ADVETA

POWER PRIVATE LIMITED. During site visit levels at Barrage site and powerhouse

were taken for confirmation of available fall in the river, and topography has been

studied. It is found that right bank is suitable for placing project components.

Accordingly, project layout has been prepared.

5.2 DETAILED TOPOGRAPHICAL SURVEY

Upon allotment of the project detailed topographical survey will be carried out to

generate topographical maps with suitable contour interval and scale for optimization of

all the project components.

5.3 REGIONAL GEOLOGY AND TECTONICS

REGIONAL GEOLOGY

The Upper Tertiary sediments, mostly coarse to medium clastics, Gondawanas-

predominantly carbonaceous sediments with sedimentation basic volcanic, and the

metamorphites and crystallines are noted in the regional area.

GEOLOGY OF THE AREA

As per the geological observation the following sequence of rocks is encountered in the

area:

River Born Material

Recent Tallus / Scree and Flood Deposits




In – situ soil

Central Himalayan Recrystallized Quartzite Grading into streaky banded gneisses

Crystalline

River Born Material

River Born Material is found deposited in the river bed. It consists of loose large

boulders, pebbles, grit, sand and silt. This loose material is continuously modified during

the floods.

Tallus / Scree Deposits

Tallus/ Scree Deposits is found at a number of places. Village Aruruga, IB PWD and

other settlements are situated over old land slide areas, which have attained stability in

due course of time. Small terraces formed due to tallus deposits are also noted along

the banks of river and seasonal nalas. Tallus materials consist of boulders, pebbles and

grit set in a matrix of sand, silt and clay. On the terraces made up of tallus material

cultivation is done on a large scale.

Streaky Gneisses (Gneisses Quartzite)

Recrystallised sericitised quartzite observed in the area probably bolongs to Bomdila

Group. Greyish white coloured fine to medium grained recrystallised quartzite is found

exposed at certain places such as diversion site and near the Power House site. On the

opposite bank these quartzites are found grading into streaky banded gneisses and

porphyroblastic gneisses. The quartz grains in these quartzites show recrystallisation

and orientation along the foliation plane. These grains are surrounded by oriented flakes

of sericite etc.

Gneisses show banded characters. The dark coloured layers of gneisses are made up

of mainly biotite and the light coloured layers are of quartz and feldspars. Porphyroblast

of quartz and feldspars are common in these rocks. Tourmaline needles are also noted

along with specks of pyrite. The rocks are well foliated and jointed. Recrystallized grains

of quartz and other flaky materials are found oriented along the foliation planes. The




arenaceous bands of gneisses are made up of quartz and feldspars and garnet,

whereas alternating argillaceous bands are made up of biotite, muscovite, chlorite and

fine quartz grains. The associated minor minerals are staurolite, ilmenite, apatite,

monazite, zircon and pyrite etc. The flaky minerals along with recrystallized quartz

grains show orientation along the foliation planes.

5.4 SEISMICITY & SEISMOTECTONICS OF THE AREA

Seismically the North-Eastern parts of the Himalayas are one of the most active zones

in the world. Itis located at the tri-junction of three tectonic plates; the Indian, the Indo-

Burmese and the Eurasian.

These plates are constantly in collision with each other as a result the rocks of this area

has undergone repeated intense folding, faulting and thrusting in a highly complex way

so much so that many of the rock sequences have either been eliminated or repeated.

The structural pattern has atmost of the times controlled the drainage pattern of the

rivers. This pattern is generally elongated in an ENE-WSW to NE-SW direction but

many transverse structural features have modified them Neo-tectonic activity is

identifiable in form of rejuvenation of existing tectonic lineaments and development of

cross- faults. It is these cross-faults that have controlled the sedimentation of the Older

(Mid. to Lr. Pleistocene) and the Newer (Holocene) Alluviums and have off-set the major

thrusts; viz. the MCT (Main Central Thrust), the MBF (Main Boundary Fault) and the

FHF (Foot Hills Fault). Almost all the epicenters of earthquakes are concentrated along

major cross faults whereas no evidence of activity is observed along the latter.




As per the Seismic Zoning Map of India (IS 1893(Pt-1):2002), the whole of the

Northeast including

Arunachal Pradesh has been placed in Zone V. This Zone is susceptible to major

earthquakes.

Between 1897 and 1984 about 20 major earthquakes with magnitude greater than 7

(Richter), and 5with more than8.0 (Richter) have been recorded in the area. While the

former (M >7) have a return period of 11 – 17years, the latter (M>8) it is 23 - 27 years.

Although the IS Code suggests design seismic co-efficient based on Maximum

Considered Earthquake, yet these values may be taken only for preliminary designs.

5.5 CONSTRUCTION MATERIAL

Suitable sites for construction material in the nearby area of the project will have to be

identified during preparation of Detailed Project Report. River sand deposits would be

tested for its suitability for use as fine aggregate in concrete and crushed sand may also

be used to obtain well graded sand.

5.6 RECOMMENDATIONS

The project site of CHELA (KOLORIANG) Hydro Electric Project is geologically & geo-

technically suitable and recommended for further investigation.




CHAPTER 6

CONCEPTUAL LAYOUT AND PLANNING




CHAPTER 6

CONCEPTUAL LAYOUT AND PLANNING

6.1 INTRODUCTION

The CHELA (KOLORIANG) HE project is located on Kurung River near KOLORIANG,

Kurung Kumey district of Arunachal Pradesh. It is a diurnal peaking scheme to harness

hydro power potential of the river Kurung, a tributary of river Subansiri. A maximum

gross head of the order of 145 m proposed to be utilized for power generation. The

powerhouse will have to be planned for installation of 3 generating units each of 25 MW.

6.2 LAYOUT OPTMIZATION

Actual optimization of the project layout shall be possible only at Detailed Project Report

stage, when all the factors influencing such optimization are known in detail. Layout

evolved in the Pre-feasibility Report is therefore, preliminary in nature.

Following factors should be considered in the optimization process:

River characteristics and type of scheme

Selected Barrage Location

Interface with upstream and downstream schemes

Barrage height

Barrage type

Associated components of the project




6.3 PROJECT COMPONENTS

The KOLORIANGHE project envisages construction of:

A 28m high barrage having FRL at EL 895 m.

A simple surge shaft of 12m diameter

Head race tunnel of 8.6 km long, 5.0 m finished diameter together with 400

m long 5 meter diameter steel pipe at the crossing of Headrace Tunnel at

PANYU river

1 no. of pressure shaft with 4 m diameter and 300 m long which at the end

trifurcating into three unit Penstocks each of 3 m diameter and 10 m long

near the powerhouse.

A surface powerhouse having an installation of three Francis turbines driven

generating units of 25 MW each.

6.4 FURTHER STUDIES

A. Topographical Studies

Topographical contour Survey of the following areas shall be taken up to firm up the

various components ofthe project.

Reservoir Survey

1:10,000 scale with contour interval of 10 and river cross sections atevery 500m in the

reservoir area.

Barrage / Powerhouse area – 1:2,000 scale with 2m contour interval.

Headrace tunnels – 1:5,000 scales with 10m contour intervals.

Intake, Adits / tunnels Portals and TRT outlet - 1:500 scale with contour interval at 1m.




B. GEOLOGICAL AND GEO-TECHNICAL INVESTIGATIONS

Geological/geo-technical investigations including surface mapping and subsurface

explorations like exploratory drilling/drifting and seismic profiling at the dam and

powerhouse area. Rock mechanic laboratory tests shall be required for finding out the

properties of the rock material. Construction material survey shall be required to be

undertaken involving drifts, pits, and topographical surveys of the borrow/quarry areas.

Site-specific studies for earthquake design parameters shall also require being

undertaken.

C. DESIGN STUDIES

Hydraulic design of various structures like spillway, power intake, and transient studies

of surge shaft shall be required for firming up the dimensions. Stability analysis of non-

overflow and overflow sections shall have to be done taking into account the seismic

parameters. Hydraulic model studies for reservoir and Dam spillway shall be required

for the confirmation of design parameters.




CHAPTER 7

POWER POTENTIAL STUDIES




CHAPTER 7

POWER POTENTIAL STUDIES

7.1 INTRODUCTION

The Chapter contains the optimization of power potential of the project on the basis of

10-daily average values of discharge available in the river in a 90 % dependable year.

The relevant parameters of the project are given below:

Installed capacity 75 MW

No. & Types of Power House 01 Surface

No. & size of unit 3 x 25 MW

Net head 130.5 m

Design discharge 67.86 m3/s

Type of switchyard 132 kV

Turbine type Francis

7.2 Power Potential Study and Annual Energy Generation

Based on likely 10-daily average discharge values in a 90 % dependable year, and

rated net head of 130.5 m, annual energy generation has been worked out. The

calculations are attached in Annexure-7.1. From the calculations, it has been inferred

that capacity of 75 MW with by installing 3 generating units each of 25 MW is the most

appropriate at preliminary design level study. However, further optimization of installed

capacity shall be carried out during preparation of Detailed Project Report (DPR).

Gross Annual Energy Generation in 90 % dependable year works out to 457.42 MU




CHAPTER 8

COST ESTIMATES




CHAPTER-8

COST ESTIMATE 8.0 GENERAL

The estimate has been prepared to arrive at the capital cost of CHELA

(Koloriang) H.E. Project and is of Pre- feasibility level of accuracy. Estimate is

based on March 2012 price level and the cost is expressed in Indian Rupees.

The Cost Estimate is divided into Civil, Electrical and Transmission Works. For

Civil Works, the sub heads are as under: -

8.1 I-WORKS

Under this head, provision has been made for various components of the Project

as detailed hereunder: -

8.1.1 A-PRELIMINARY

Under A-Preliminary, provision has been made for all surveys and investigations

to be conducted to arrive at the optimum of the Project Components.

8.1.2 B-LAND

This covers the provision for acquisition of land for construction of the Project

colonies, offices and stores and compensation for trees and standing crops etc.




8.1.3 C-WORKS

This covers the cost of Diversion Tunnel, Coffer and Concrete Dam and Spillway

along with associated Hydro-mechanical equipment.

8.1.4 J-POWER PLANT CIVIL WORKS

This covers the cost of project components viz. Intake Structure, Headrace

Tunnel and TRT, Powerhouse and Transformer Cavern, Pressure Shaft,

Switchyard and other Appurtenant Works. The quantities indicated in the

estimates for C - Works & J-Power Plant Civil Works (Civil & HM) are calculated

from the preliminary engineering drawings and as per experience of other on-

going or commissioned projects. The unit rates for various items are taken as per

the Guidelines issued by CEA for preparation of PFRs.

8.1.5 K-BUILDINGS

Buildings, both residential and non-residential have been provided under this

head. Under the permanent category only those structures have been included

which shall be subsequently utilized during the operation and maintenance of the

project. The costs are worked out on plinth area basis prevalent in the area for

the type of construction involved.

8.1.6 O-MISCELLANEOUS

Provision under this head has been made @ 4% of I- works for the Capital &

running cost of Electrification, Water Supply, Sewage Disposal, Fire Fighting

Equipment’s, Medical Assistance, Recreation, Post Office, Telephone and




Telegraph Office, etc. The Provisions have been made for the security

arrangements, inspection vehicles, schools, transport of labour, laboratory

testing, R&M of guest house and transit camps, community center, retrenchment

compensation, photographic instruments as well as R&M charges etc.

8.1.7 P-MAINTENANCE DURING CONSTRUCTION AND Y-LOSSES ON

STOCK

A provision of 1% and 0.25% of C-Civil works, J-Power Plants, K Buildings & R-

Communications has been made for maintenance of works during construction

period and losses on stock respectively.

8.1.8 Q-SPECIAL TOOLS AND PLANT

It is assumed that the work will be carried out through Contracts and not through

departmental construction. Accordingly, provision for general purpose equipment

and inspection vehicle only has been made as per CWC guidelines.

8.1.9 R-COMMUNICATION

Provision under this head covers the cost of new roads, widening/improvement of

roads and strengthening of bridges. The costs of roads and bridges are based on

the rate structure prevalent in the area of the Project for the type of construction

involved.

8.1.10 X-ENVIRONMENT AND ECOLOGY




Provision under this head has been taken as 2% of I –Works towards bio-

diversity Conservation, creation of Green Belt, Restoration of Construction Area,

Catchment Area Treatment, Compensatory Afforestation etc

8.2.1 II-ESTABLISHMENT

Provision for establishment is normally made at 6 to 8% of I-works minus Bland

for civil works. However, in the present estimate provision has been made based

on experience in other projects.

8.2.2 III-TOOLS AND PLANTS

This provision is distinct from that under Q-Special T&P and is meant to cover

cost of survey instruments, camp equipment and other small tools and plants.

The outlay is provided at 1% of cost of I-works.

8.2.3 IV-SUSPENSE

No provision has been made under this head as all the outstanding suspense are

expected to be cleared by adjustment to appropriate heads at completion of the

project.

8.2.4 V-RECEIPTS AND RECOVERIES

Under this head, provision has been made for estimated recoveries by way of

resale or transfer of equipment used in infrastructure works.




8.2.5 ELECTRICAL WORKS AND GENERATING PLANT

The cost of Generating Plant and Equipment is based on indigenous sources.

The prices of auxiliary equipment and services are based on prevailing market

prices/costs incurred at other ongoing or commissioned projects.

8.3 BROAD ESTIMATED COST

Based on the project components envisaged as per general layout of the project,

location of the project, requirement of developing infrastructure facilities, broad

estimate of project cost under various heads is attached in Annexure-8.1




CHAPTER 9

FINANCIAL ANALYSIS




CHAPTER-9

FINANCIAL ANALYSIS 9.1 GENERAL

The Project has been contemplated as a run of the river scheme on river Kurung.

The project is estimated to cost Rs. 543.31croresincluding escalation and interest

during construction (IDC), Financial Management charges at March 2012Price

Level. Tariff of energy generated for first year at powerhouse bus bars has been

worked out as Rs. 3.06 per kWh and levellised tariff as Rs 2.65 per kWh based

on CERC guidelines.

9.2 ECONOMIC JUSTIFICATION

The energy generation of the project with an installed capacity of 3 x 25MW has

been estimated at 457.42 MU in a 90% dependable year

9.3 COST ESTIMATES AND PHASING OF EXPENDITURES

The cost of construction of the project has been estimated at March 2012 price

level with a construction period of 4.0 years including 1.0 year for pre

development including preliminary infrastructure and pre – construction works.

The estimated Cost of the project including escalation @ 3% p.a is Rs.

543.31Crores with IDC, FM charges March 2012price level.




9.4 PHASING OF EXPENDITURE

The phasing of expenditure has been worked out on the basis of anticipated

construction Program

The phasing of expenditure without IDC for the present cost is shown in

Annexure-9.1.

9.5 INTEREST DURING CONSTRUCTION (IDC)

Based upon above phasing of expenditure the interest during construction (IDC)

has been calculated with 70:30 debt equity ratio and 12% interest on loan.

The estimated IDC with estimated present cost is Rs. 69.42crores

9.6 COST OF ENERGY GENERATION

The cost of energy generation has been calculated for the annual energy

generation in a 90% dependable year based upon following assumptions.

1. Debt-equity ratio 70:30

2. Annual interest rate on loan 12%

3. Return on equity 19.38%

4. Annual interest rate on working capital 13.50%

5. O&M Charges 2% of Project Cost

6. Free power to Home State 12 %




7. Depreciation considered 1/10th of loan amount during Loan repayment period.

The levellised tariff of the Project of the project at anticipated cost works out to be

Rs. 3.06 per kWh at price level March 2012.




CHAPTER 10

RECOMMENDATIONS




CHAPTER – 10

RECOMMENDATIONS

10.0 RECOMMENDATIONS

10.1 GENERAL

The project involves construction of conventional civil structures as detailed

below.

Gated Barrage comprising spillways and under sluiceways

Power Intake

Feeder Tunnels

Underground De-silting chambers

Circular Head Race Tunnel

Vertical Surge Shaft

Pressure Shaft and 3 nos. unit Pressure shafts

Surface powerhouse with installed capacity of 75 MW by installing 3

generating units each of 25 MW

Switchyard

Tail Race Channel

Dedicated transmission line up to proposed KOLORIANG Substation

Access Roads and Bridges

The project construction work is expected to be completed in a period of 60

months including 12 months for development of infrastructure facilities.




10.2 PRELIMINARY AND PRE-CONSTRUCTION WORKS

To ensure project completion in 60 months, it is essential to accomplish the

following activities in a period of 12 months including obtaining all clearances

before start of Main Civil works. However some of the activities will continue

during construction of main civil works:

Acquisition of land

Completion of main infrastructure facilities such as roads and buildings,

bridges across Ravi River.

Completion of detailed design and specifications

Financial Closure

Tender and award of main Civil, Hydro-mechanical and Electro-

mechanical works.

10.3 CIVIL AND HYDRO MECHANICAL WORKS

A total time period of 48 months has been considered for main Civil and Hydro-

mechanical works. The Head race tunnel construction falls in critical path.

Adequate construction equipment planning will have to be done to achieve the

desired progress rates while preparing the detailed project report .Timely

completion of construction works also depends on the timely supply of

construction material to various project components through development of

project roads. Sufficient storage shall be ensured at project sites to ensure

continuous construction without stoppage due to shortage of materials.

10.4 ELECTRO-MECHANICAL WORKS

Three numbers of 25 MW Vertical Francis machines have been proposed to

generate 75 MW of power. The orders for Electro-Mechanical equipment’s will

have to be placed in line with civil works so as not to cause any delay in

completion of civil works in power house.




For power evacuation, a 3 km long dedicated 132 kV single circuit line to

proposed sub-station at Koloriang is required.

10.5 CONSTRUCTION POWER

Availability of adequate construction power plays a major role in the scheduled

completion of construction works. Construction power required for various

components shall be supplied through dedicated D.G. Sets. However, if power is

available in the local grid the same shall also be utilized for construction of the

project.

10.6 COST OF THE PROJECT AND CORRESPONDING BENEFITS

Capital cost of the project is estimated as Rs543.31crores and design annual

energy benefit from the project in 90% dependable year 95 % of the project

capacity is 444.61 MU viz. cost of installation of the project is Rs11.87 / kWh and

is in the techno-economic viability range for hydro-electric project of this size.

10.7 RECOMMENDATIONS

The installed capacity of about 75 MW based on the project

layout proposed in this PFR appears technically feasible.

The project is attractive from accessibility point of view.

Upon allotment of the project following would need to be taken on priority.

Detailed topographical survey of the entire project area

Detailed Geological Investigations especially at proposed location

of project components.

Discharge measurements be started at proposed diversion site

EIA study and forest clearance




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