Naying - Ministry of Power

50 000 MW HYDROELECTRIC INITIATIVE 

1000 MW NAYING H.E. PROJECT 

ARUNACHAL PRADESH 

Preliminary Feasibility Report 

Consultant : 

Government of India 

Ministry of Power 

Central Electricity Authority 

January 2004 

National Hydroelectric Power Corporation Ltd. 

(A Government of India Enterprise)

Foreword 


Naying HE Project(4 x 250 MW) 

With the growing demand for power day by day and also for a sustainable economic growth of 

our country, be it for industrial growth or infrastructure development, , Hydropower has a very essential 

role to play in the days to come. All other resources for power being exhaustible, gradually depleting and 

at times hazardous, the hydropower offers an wonderful alternative for which resources is inexhaustible 

and environment friendly. Although India has hydropower generation history of more than 100 years, it 

has contributed only about 25% to the total power scenario of the country tapping 26,910 MW of its 

total identified hydropower potential of 84,044 MW, till date. Looking at the future demand, it has 

become imperative to tap this vast hydropower potential. Honorable Prime Minister Shri A. B. Vajpayee 

has taken a giant step by launching “50 000 MW Hydroelectric Initiative” in May 2003 , to accomplish 

the goal by XI th Plan and beyond. This will put the country on the faster track to progress. 

NHPC feels honoured to be associated with this venture which intends to create a shelf of Pre- 

Feasibility Reports(PFRs) of 162 projects by September,2004 for taking up their phase-wise 

implementation. NHPC is entrusted with the responsibility of preparation of 43 PFRs with a likely 

capacity addition of 21,345 MW. The entire work of preparation of PFRs is being carried out by inhouse 

team of experts in NHPC.. After scrutiny by various departments of CEA/CWC, Naying HE 

Project, prepared by us, earns the unique distinction of first PFR to be finalised in Siang Basin. Located 

in the Siang Basin in Arunachal Pradesh it has an installed capacity of 1000 MW . The estimated cost of 

the Scheme stands at Rs. 3016.96 crores at June, 2003 Price Level and it will give power at a unit rate of 

Rs.1.09 per KwH. The levellised tariff without free power to home state comes to Rs. 0.96 per KwH. 

We are grateful to the CEA and Ministry of Power for reposing their faith on us and offering 

this unique opportunity to be a part of this noble initiative and we promise to put up our best effort to 

achieve the objective as set by our Honorable PM. We, also, take this opportunity to offer our sincere 

gratefulness to all the Departments and Organisations viz.- CEA, CWC, GSI, SOI, NRSA, and various 

Departments of Government of Arunachal Pradesh for lending their kind co-operation in completing this 

task. 

Faridabad ( Yogendra Prasad ) 

12.01.2004 Chairman & Managing Director

CHAPTER 

TABLE OF CONTENTS 

(i) 


Naying HE Project (4 x 250 MW) 

DETAILS PAGE NO. 

CHAPTER I Summary 01-08 

CHAPTER II Background information 09-11 

CHAPTER III Project Area 12-13 

CHAPTER IV Topographic & Geo-technical Aspects 14-27 

CHAPTER V Hydrology 28-41 

CHAPTER VI Conceptual Layout and Planning 42-52 

CHAPTER VII Power Potential Studies 53-81 

CHAPTER VIII Power Evacuation 82-83 

CHAPTER IX Environmental Aspects 84-97 

CHAPTER X Infrastructure 98-104 

CHAPTER XI Construction Planning & Schedule 105-109 

CHAPTER XII Cost Estimates 110-113 

CHAPTER XIII Economic Evaluation 114-119 

APPENDIXES

LIST OF TABLES 

CHAPTER TABLE NO TITLE 

(ii) 



PAGE 

IV 4-1 Lithostratigraphic succession of the 

Himalayan part of the Eastern Syntaxial 

Bend, A.P. (After, S.Singh, 1993). 

17 

4-2 Lithostratigraphy of the Siang Group 

(After, S.Singh, 1993). 

18 

4-3 The major joints sets 22 

4-4 The major joints sets encountered in Power 

House area 

24 

V 5-1 Existing raingauge stations and period of 

data availability in catchment of Siang Middle 

32 

5-2 Location of G&D sites 33 

5-3 Comparison of various flood values 36 

VII I Discharge Data 58 

II 90% Dependable Year Flows for Power 

Generation 

59 

IIIA Reservoir Operation Report 60 

IIIB Reservoir Operation Report 61 

IV Reservoir Operation Study (Year 2002-03) 62 

V Power Potential in 90% Dependable Year 63 

XI 11.1 Schedule of execution of Stage-I and Stage- 

II activities 

109(a) 

11.2 Construction Schedule 109(b) 

XIII 13.1 IDC Calculation at Present Day Cost 117 

13.2 Unit Cost of Energy at Bus Bar at Current 

Price Level 

118 

13.2-A Unit Cost of Energy at Bus Bar at Current 

Price Level without Free Power to State 

Government 

118(A) 

13.3 Energy Rate with Present Cost 119 

13.3-A Energy Rate with Present 

Cost without Free 

Power to State Government 

119(A)

CHAPTER PLATE NO 

LIST OF PLATES 

II 2.1 Index Plan 

(iii) 



TITLE 

IV 4.1 Preliminary Geological Cross Section Along 

Proposed Dam Axis 

V 5.1 Catchment Plan of Basin Projects 

VI 6.1 General Layout Plan 

6.2 Dam Complex General Layout 

6.3 Dam Cross Sections 

6.4 Downstream Underground Works General Layout 

Plan 

6.5 Dam Upstream Elevation 

6.6 Water Conductor System Longitudinal Section 

VIII 8.1 Single Line Diagram 

CHAPTER FIG NO 

LIST OF FIGURES 

TITLE 

V I Reservoir Elevation Area Capacity Curve 

LIST OF ANNEXURES 

CHAPTER ANNEXURE TITLE 

V Annex.-1 Average 10-daily discharge

LIST OF APPENDIX 

APPENDIX- I Preliminary Cost Estimates 

APPENDIX- II Drawings 

APPENDIX- III Ranking Study by CEA 

APPENDIX- IV Conceptual Planning approval by CEA 

APPENDIX- V Report of Geological Survey of India 

(iv) 



APPENDIX- VI Comments of CEA vide 7/9(NHPC)/2003/HP&I/1044 dated 

07.10.03 & U.O. No. 82/18/2003-SP&PA/ dated 

23.10.2003 & Reply of NHPC 

APPENDIX- VII Comments of CWC on Hydrology vide Letter No. 4/330/2003 

HYD NE/341 Dt. 28-10-2003 & Reply of NHPC 

APPENDIX- VIII Comments of CWC on Hydrology vide Letter No.4/330/2003 

HYD NE/399 Dt. 31-12-2003 & Reply of NHPC 

APPENDIX- IX Comments of CMDD Directorate, CWC issued vide CWC 

U.O. No. 0/2/2003/CMDD(E&NE)/229 dated 08.01.2004 & 

Reply of NHPC 

APPENDIX- X Comments of HCD (E&NE), Directorate CWC issued vide 

U.O. No. 3/5/2000-HCD(E&NE)/711 dated 08.01.2004 & 

Reply of NHPC 

APPENDIX- XI 

NRSA Report on initial environmental studies

CHAPTER – I 

EXECUTIVE SUMMARY

1.0 INTRODUCTION 

CHAPTER - I 

EXECUTIVE SUMMARY 


Naying HE Project (4 X 250 MW) 

The Naying HE Project located in West Siang district of Arunachal 

Pradesh envisages utilization of the waters of the river Siyom river (a 

tributary of Siang River) for power generation on a run of river type 

development, harnessing a head of about 240 m in a stretch of about 

10kms. The project lies upstream of Siang Middle (Siyom) HE Project and 

downstream of Tato-II HE Project on the same river. 

The project with a proposed installation of 1000 MW (4x250 MW) would 

afford an annual energy generation from the project in 90% dependable 

year was estimated to be 4966.76 MU. 

The proposed dam site is located at 28°31'10" N & 94°30'25" E which 

is 40km upstream of Siang Middle dam site & 4km down stream of 

village Yapik. The project is located 100km upstream of Along Town 

(an important district town of Arunachal Pradesh) and 800kms from 

Guwahati (the capital city of Assam and the largest city of North – 

East). The nearest big rail head is located at Nagaon and nearest 

airport is located at Guwahati. 

1.1 SCOPE OF WORKS 

The Naying HE Project envisages construction of : 

• A concrete dam, 105m high above riverbed and 255m long at the top. 

• River diversion works comprising of 2 Nos, 9.5m dia, diversion tunnels 

with upstream and downstream coffer dams. 

• 2 Nos. Head Race Tunnels, 8.5m dia, horseshoe shaped, concrete 

lined, 6.5km long approximately. 

1



• 2 Nos., 25m dia and approx. 125m high surge shafts. 

• 2 Nos., steel lined, circular pressure shafts of 7m dia. 

• An underground power house complex housing 4 units of 250MW. 

• 2 Nos., 8.5m dia horse shoe shaped Tail race tunnels of about 500m 

length. 

The power generated from the project would be evacuated through 400 

kV double circuit lines to a pooling station near Kamki to feed power to 

power grid. 

The Salient features of the project are given at Annex-I. 

1.2 RESULTS OF STUDIES AND INVESTIGATIONS 

1.2.1 Hydrology 

The catchment area of river Siyom upto the proposed dam site is about 

2756 sq.km. The submergence area at full reservoir level is estimated as 

1.89 sq. km. The water availability for the project has been done on the 

basis of average 10-daily discharge series given for Middle Siang H.E. 

Project for the period 1978-2003. The water availability has been derived 

on the basis of catchment area proportion and applying an overall 

reduction factor of 0.84. The computed inflow series worked out has 

been utilized for Power Potential studies. The design flood has been 

assessed as 11500 cumec. 

1.2.2 Power Potential Studies 

The computed inflow series for 19 years viz June 1978 to May 1994 & 

June 2000 to May 2003 has been considered in the assessment of a 

power benefits from the projects. As per GOI notification for tariff the year 

2002-03 corresponds to 90% dependable year. An installation of 1000 

MW comprising 4 generating units of 250 MW has been proposed. The 

2



energy availability from the project in a dependable and an average year 

has been summarized below: 

Particular Dependable Year 

Annual Energy Generation (GWh) 

Annual Energy Generation (GWh) 5077.15 

Annual Load Factor (%) 57.96 

Generation during Lean Flow Season (Dec. - Feb.) 

Power Output (MWc) 166.81 

Load Factor (%) 16.68 

The design energy for tariff at 95% availability in a 90% dependable year 

has been worked out at 4966.76 GWh. 

A pondage of 55 mcum has been provided in the diversion dam which 

would enable the station to operate as peaking station. The pondage is 

equivalent to 31939.18 MWh which is sufficient to operate the station for 

33.74 hrs. 

1.2.3 Power Evacuation Aspects 

The power generated from the project would be evacuated through 400 

kV., double circuit lines to a pooling station near Kamki to feed into the 

Grid which in turn would be connected to National Grid,. 

1.2.4 Environmental Aspects 

The project is located in very remote area of West Siang district. The 

total land requirement for the construction of various components is 600 

ha which falls under the category of private land with degraded forest 

cover. Based on assessment of environmental impacts, management 

plans have to be formulated for Catchment Area Treatment, 

Compensatory afforestation and other environmental issues. These 

issues would be addressed during the investigation for DPR. 

3

1.2.5 Estimates Of The Cost 



The project is estimated to cost Rs. 3016.96 crores, which includes an 

IDC at June 2003 price level. The preliminary cost estimate of the project 

has been prepared as per guidelines of CEA / CWC. The break down of 

the cost estimates is given below : 

1.2.6 Financial Aspects 

Civil works : Rs. 1726.99 Crores 

Electro Mechanical Works : Rs. 803.34 Crores 

Sub total (Generation) : Rs. 2530.33 Crores 

Transmission works : Rs. 99.96 Crores 

Total (Hard cost) : Rs. 2630.29 Crores 

Interest during construction : Rs. 386.67 Crores 

Grand Total : Rs. 3016.96 Crores 

As indicated above, the Naying H.E. Project with an estimate cost of Rs. 

3016.96 crores (including IDC of Rs. 386.67 crores) and design energy of 

4967 GWh in a 90% dependable year is proposed to be completed in a 

period of 7 years. The tariff has been worked out considering a debtequity 

ratio of 70:30, 16% return on equity, annual interest rate on loan at 

10% and 12% of energy as free power to Home State available after 

losses. The tariff for first year and levellised tariff have been worked out 

as Rs. 1.34 / kWh & Rs. 1.09 / kWh respectively. The tariff for first year 

and levellised tariff without free power to state government comes to Rs. 

1.18 / kWh & 0.96 / kWh respectively. 

1.2.7 CONCLUSIONS 

Naying HE Project involves simple civil works and could be completed in 

7 years. The project would afford a design energy of 4967 GWh in a 90% 

dependable year. The cost per MW installed works out Rs. 3.017 crores. 

The Preliminary Feasibility Report indicated that the scheme merit 

consideration for taking up for Survey & Investigation and preparation of 

DPR. 

4

1 LOCATION 

SALIENT FEATURES 



i) State Arunachal Pradesh 

ii) District West Siang 

iii) River Siyom 

ii) Location of Dam site 

Latitude 28 0 31’10’’ 

Longitude 94 0 30’25’’ 

iii) Location of Power House 

Latitude 28 0 31’56’’ 

Longitude 94 0 34’10’’ 

iv) Nearest big rail head Nagaon 

v) Nearest Airport Guwahati 

2 HYDROLOGY 

i) Catchment area 2756 km 2 

ii) Design flood (PMF) 11500 cumecs 

3 DIVERSION TUNNEL 

i) Diameter & shape 2 nos. 9.0 m dia 

Horseshoe Shaped 

Annexure -I 

ii) Length 600 m each 

iii) Diversion discharge 2000 cumecs ( Non monsoon) 

iv) Diversion tunnel gate 1 no. vertical lift gate each 

v) Size of gate 6.75 X 9m 

4 COFFER DAMS 

i) Type Rockfill with central clay core 

( Overflow Type ) 

ii) Max. height of u/s + 20.0m 

Coffer dam 

iii) Max. height of d/s + 10.0 m 

Coffer dam 

5

5 DAM 



i) Type Concrete gravity 

ii) Dam top El. 810 m 

iii) River bed level at dam site El. 705 m 

iv) Max. dam height (above 125.0 m 

Deepest foundation level) 

v) Length of dam at top 255 m 

vi) Dam height (above river 105 m 

bed level) 

6 SPILLWAY 

i) Design flood 11500 cumec 

ii) Crest elevation Upper level 785 m 

Lower level 735 m 

iv) Nos. and size of spillway 

opening 

a) Lower level (w x h) 5 nos. 7 m X 7.3 m 

b) Upper level (w x h) 4 nos. 9 m X 12.5 m 

v) Energy dissipation Ski jump 

7 RESERVOIR 

i) Full Reservoir level (FRL) El 805 m 

ii) Min. draw down level El 765 m 

iii) Area under submergence 2.00 sq. km 

at FRL 

iv) Gross storage 82 Mcum 

v) Live storage 57.9 Mcum 

8 INTAKE 

i) Numbers Two 

ii) Invert level El 745 .00 m 

iii) Size of each gate 7.0 m X 9.0 m 

iv) Design discharge 226 cumecs each 

v) Total Design discharge 452 cumecs 

9 HEAD RACE TUNNEL 


ii) Size & type 8.5 m dia, horse shoe 

shaped, concrete lined. 

iii) Design discharge 226 m cumecs each 

iv) Length 6.5 km each 

v) Adits 3 nos. 6.5 m D- shaped 

6

10 SURGE SHAFT 


ii) Size & type 25 m diameter 

iii) vertical shaft height 120 m 

11 PRESSURE SHAFT / PENSTOCK 




ii) Type Steel lined , two 

iii) Diameter 7.0 m 

iv) Underground pressure 300 m 

Shaft length 

12 POWERHOUSE COMPLEX 

13 TRT 

i) Numbers of caverns Three ( MIV cavern, 

Powerhouse cavern and 

Transformer cavern) 

i) Type Underground 

ii) Tail water level at outlet 520 m 

iii) Turbine axis elevation 514.50 m 

iv) Type of turbine Vertical francis 

iii) Generating units 4 x 250 MW 

iv) Gross head 285 m 

v) Rated net head 245 m 

vi) Power house size 135 m X 22m X 44.5 m 


ii) Size & type 8.5 m dia, horse shoe 

shaped, concrete lined. 

iii) Design discharge 226 m cumecs each 

iv) Length 500 m each 

14 POTHEAD YARD 

i) Type, size Surface, 150 m X 60 m 

15 POWER GENERATION 

i) Installed capacity 1000 MW ( 4 X250 MW) 

ii) Annual energy generation 

(a) 90% dependable year 5077.15 GWh 

(b) Energy in 90% year on 4966.76 GWh 

95% availability 

7

16 COST ESTIMATES & FINANCIAL ASPECT 



Civil works : Rs. 1726.99 Crores 

Electro Mechanical Works : Rs. 803.34 Crores 

Sub total (Generation) : Rs. 2530.33 Crores 

Transmission works : Rs. 99.96 Crores 

Total (Hard cost) : Rs. 2630.29 Crores 

Interest during construction : Rs. 386.67 Crores 

Grand Total : Rs. 3016.96 Crores 

Tariff for first year : Rs. 1.34 per kWh 

Levelised Tariff : Rs. 1.09 per kWh 

Tariff for first year without : 

free power to state govt. 

Rs. 1. 18 per kWh 

Levelised Tariff without free 

power to state govt. 

: Rs. 0.96 per kWh 

17 CONSTRUCTION PERIOD 7 Years 

8

CHAPTER – II 

BACKGROUND INFORMATION

2.0 BACKGROUND 

CHAPTER - II 

BACKGROUND INFORMATION 



The Naying HE Project is one of the 43 schemes entrusted to 

NHPC by CEA for preparation for Pre feasibility reports under 

Prime Minister’s 50,000MW initiative. 

2.1 THE PROJECT AS CONCEIVED BY CEA 

The Naying HE Project conceived by CEA across Siyom river (a 

tributary of Siang River) consists of harnessing of a head of 240m 

in a stretch of about 10kms. The project lies upstream of Siang 

Middle (Siyom) HE Project and downstream of Tato-II HE Project 

on the same river. Following parameters were preliminarily worked 

out by CEA. 

• Capacity of Power plant 500MW. 

• A diversion dam with a river bed level at 710m. 

• A power channel – 9km long. 

• A power house with tail race level at 470m. 

The annual energy generation from the project in 90% and 50% 

dependable year was estimated to be 2480MU and 2780MU respectively. 

Details of ranking study carried out by the CEA is enclosed as Appendix- 

III. 

2.2 INITIAL APPRAISAL BY NHPC 

Since NHPC is already having field organization for 1000MW Siang 

Middle (Siyom) HE Project at Along, the Project site of Naying Project 

was visited by NHPC team. NHPC also studied this project viz.-a-viz. 

9



Siang (Middle) HE Project, the Detailed Project Report of which has 

recently been prepared by NHPC. The brief feature of Siang Middle 

(Siyom) HE Project are as under: 

a) Location of Dam site – Village Raying (56Kms. u/s of Along 

Town). 

b) Dam Height – 169m. 

c) River Bed level – EL 356M. 

d) FRL of Dam – EL 510M. 

e) Max. Water Level – EL 520M. 

f) Capacity of Power Plant – 1000MW. 

g) Length of reservoir at FRL – 17.5kms. 

2.3 LAYOUT OF NAYING PROJECT DISCUSSED WITH CEA 

Layout of the project was discussed with CEA by NHPC team on 

17.09.2003 and minutes are enclosed as Appendix-IV. It was brought by 

NHPC that Tail Water Level of the project needs revision in view of the full 

reservoir level of Siang Middle (Siyom) HE Project. NHPC further 

proposed a Head Race Tunnel instead of the channel for the Water 

Conductor System. These conceptual changes were agreed by CEA. 

Hydrology of the project and the power plant capacity were further 

discussed with CEA. Proposed Index Plan is enclosed as Plate 2.1. 

2.4 THE CONCEPTUAL PLANNING OF THE PROJECT 

After carrying out site visits, the hydrological studies and the power 

potential studies, following has been firmed up in the preparation of this 

PFR. 

i) Location of dam : 40km upstream of Siang Middle dam site & 

4km down stream of village Yapik. 

10



ii) Location of P.H. : 30km upstream of Siang Middle project & 

10km. downstream of Naying dam site 

(these distances are by road). 

These locations of dam and power house sites are preliminary in nature 

and shell be subject to review at the stage of detailed investigations. 

iii) Full Reservoir Level : EL 805M. 

iv) Tail Water Level : EL 520M. 

v) Gross Head : EL 285M. 

vi) Rated Net Head : EL 245M. 

vii) Installed capacity : 1000MW. 

viii) Energy Generation in 90% dependable year : 4967MU. 

It is needless to say that these figures are correct only for Pre-feasible 

stage and could undergo significant changes when detailed investigations 

for the project are taken-up at a later stage. 

11

CHAPTER – III 

PROJECT AREA

3.1 GENERAL 

CHAPTER - III 

PROJECT AREA 



The Project location falls in remotest areas of the state of Arunachal 

Pradesh with main occupation of the local populance being only 

agriculture. The main agriculture produce of the area is paddy. Besides, 

millet, pineapples, oranges, etc., are also grown but in very less quantity. 

As such there is no income to the local populance from these agricultural 

produce as it caters to their local needs due to which the people of the 

entire area are below poverty line. Although, a middle school is available 

at Tato but as such the rate of dropouts from the school is quite high. 

Thus the level of literacy is very low and unemployment rate is very high. 

Medical facilities are also very scanty. 

In the event of taking off of the Naying Project, it is envisaged that the 

economic development of the entire area will be on thrust hold. The 

project shall bring socio-economic development of not only to the project 

area but also to the other areas which are located upstream of Siang 

Middle H.E. Project. With the improved road communication, better 

education and civic amenities are bound to follow which will act as a 

catalyst for development of the entire area in all spheres. 

The project is located on river Siyom which is a tributary of river Siang. 

The river has its confluence from west with the main river Siang. The river 

is of perennial nature. A run of the river scheme is proposed. Neither 

there is population in the nearby area nor in its entire submergence area 

of said project. Moreover, there is no water requirement for riparian rights 

and discharge of river being small, it does not require flood mitigation in 

the downstream of the project location. Thus no storage scheme is 

required. 

12



The river Siyom is a perennial river with its main source being snow melt 

of Himalayan glaciers and small streams. Besides, the entire catchments 

receives moderate to heavy monsoon showers from May to October each 

year. The approximate discharge measured on 26.08.2003 has been 

observed to be 346 Cumecs i.e., during monsoon. As observed at G & D 

site of Siang Middle H.E. Project there is appreciable drop in discharge 

during the lean season i.e. November to March. 

13

CHAPTER – IV 

TOPOGRAPHIC & 

GEO-TECHNICAL ASPECTS

CHAPTER - IV 



TOPOGRAPHIC & GEO-TECHNICAL ASPECTS 


The Naying Hydroelectric scheme was handed over to NHPC Ltd. for 

framing up of Pre-feasibility report of 131 MW (firm power) Project by 

Central Electricity Authority. 

The scheme has been conceived by CEA as run-of-river scheme utilizing 

a head of about 240m in a stretch of about 10kms. The powerhouse is 

proposed about 6kms upstream of confluence of Sike with Siyom. The 

scheme would give benefit of about 131 MW of firm power with an annual 

energy generation of 2480 GWG and 2780 GWH respectively in 90% and 

50% dependable years. The scheme involves a diversion structure of 

small height on the river at a site where river bed level is + 710m, a 

channel about 9 kms. long and a power house with a tailrace level of + 

470m. The generation capacity may be about 500MW (Drg. No. HEPR- 

PS-BHM-722). 

4.1 GENERAL 

The project area falls under survey of India (S.O.I) toposheets no 82 L/10 

(28°31'10"-28°31'56"N, 94°30'25"-94°34'10"E). The area shows 

prominently one category of rock type belonging to Pari mountain 

formation of Siang group i.e. augen gneiss with a few bands of quartzites. 

The project structures viz. dam, power tunnel and the powerhouse will be 

housed in the domain of gneiss with occasional bands of quartzites. The 

gneiss shows a variation in its texture from augen to banded gneiss. The 

report of GSI is enclosed as Appendix-V. 

14

4.2 INVESTIGATIONS 



Consequent upon transfer of this project to NHPC for framing up the Prefeasibility 

report, several traverses have been taken to establish the 

discharge data, river slope, as well as the available rock type viz. -a- viz. 

the probable layout of the project. Proposed Preliminary Geological Cross 

Section along Proposed Dam Axis is enclosed as Plate 4.1. 

4.3 PHYSIOGRAPHY 

The Arunachal Pradesh could be divided into four distinct physiographic 

domains namely: 

° Himalayan ranges 

° Mishmi hills 

° Naga Patkai ranges 

° Brahmaputra plains 

Each physiographic domain has a different geology and tectonic set up. A 

brief description Himalayan ranges is as follows:- 

4.3.1 HIMALAYAN RANGES 

Himalayan ranges are the eastern most part of the Great Himalayan 

ranges and it occurs as a gigantic crescent with its convex side towards 

south and extends from Western border of Bhutan to Dibang and Lohit 

valleys in the east, abutting against Mishmi hills. This is divided in to 

following four parallel linear zones: 

a) Tethys or Tibetan Himalaya to the north. 

b) Higher Himalaya 

c) Lesser or lower Himalaya 

d) Sub Himalaya to the south 

15

4.3.1.1 Lesser Himalaya 



Lesser Himalayan hill ranges lying between the Greater Himalaya in north 

and sub Himalaya in south are of lesser height with elevation ranging 

from 2500 to 4000 m. The width is about 80-90 Kms. The southern limit 

with sub Himalaya is defined by Main Boundary Fault. 

The zone comprises of Late Palaeo-Proterozoic unfossiliferous 

sediments. In the Siang Valley, these are made up mainly of Paleozoic, 

Mesozoic, Cenozoic and Palaeogene rocks. The project area falls in a 

part of Lesser Himalaya of Arunachal Pradesh and is characterized by 

highly rugged terrain with altitude varying from 485m to as much as 

2447m (Ramne Pass) above the mean sea level and narrow to broad 

valleys. 

4.4 REGIONAL GEOLOGY 

The dominant E-W regional trend of the Arunachal Himalaya truncated 

after a sharp bend in the Siang district, where it swerves from NE-SW in 

the west to NW-SE in the east across the Siang Gorge, defining the socalled 

Eastern Syntaxial Bend (ESB). The Eastern Syntaxial Bend is 

built up of Proterozoic to Cenozoic rocks, most of which occur in the form 

of distinct thrust bound litho-tectonic belts. According to another school of 

thought, it is simply a case of meeting of two different tectonic domains 

with ENE-WSW and NW-SE trends in the west and east respectively. 

The structural architecture of the ESB comprises of three major thrust 

sheets namely Siang, Siyom and Rikor in descending tectonic order and a 

complex Para autochthonous zone discernible in the central part wherein 

the Abhor Volcanic, the Yingkiong Formation and the Dalbuing Formation 

are exposed. 

16



Based on distinct Litho association, tectonic relations, deformation, and 

metamorphic attributes, S. Singh (1993) classified the rock sequence into 

various Lithostratigraphic groups/formations. This classification has been 

used in this report. The project area is covered by rock of Proterozoic 

Age. The rock sequence of the area is constituted mainly of two 

lithostratigraphic divisions i.e. Siang Group and Siyom Group. (Refer 

Table No. 4.1). 

Table 4.1 Lithostratigraphic succession of the Himalayan part of the 

Eastern Syntaxial Bend, A.l P. (After, S.Singh, 1993). 

Tectonic Group / 

Unit Formation 

Lithology Age 

P 

A 

Siwalik 

Group 

Sandstone, siltstone, clay and boulder 

bed 

Mio-Pliocene 

R 

------------Main Boundary Thrust------------ 

A 

U 

Dalbuing 

Formation 

Nummulitic limestone and shaly 

limestone 

Lower to Middle 

Eocene 

T 

O 

C 

H 

T 

H 

O 

N 

O 

U 

S 

Rikor 

Thrust 

Sheet 

Siyom 

Thrust 

Sheet 

Siang 

Thrust 

Sheet 

Yingkiong 

Formation 

Abor 

Volcanics 

Gondwana 

Group 

Nikte 

Quartzite 

Rikor Group 

Siyom Group 

Siang Group 

Intimately associated sequence of 

sandstone, siltstone, slate, phyllite with 

volcaniclastic sediments 

Hard massive, vesicular to 

amygdaloidal basalt, agglomerates, 

Lappillies, bombs etc. 

Sandstone, shale, and diamictite 

sequence containing marine and plant 

fossils. 

Quartzite, shale/slate with conglomerate 

lenses 

------------Nelleng Thrust------------ 

Quartzite, limestone, dolomite and 

phyllite 

------------Siyom Thrust------------ 

Schistose quartzite, schists, marble 

gneisses and metavolcanics 

------------Sike Nala Thrust------------ 

Silliminite-Kyanite schists, amphibolite, 

quartzite, marble, gneisses & migmatites 


Eocene 

Late Cretaceous 

to Early Eocene 

Lower 

Permian 


Palaeozoic 

Upper 

Proterozoic 

Middle 

Proterozoic (?) 

Lower 

Proterozoic 

17

4.5 GEOLOGY OF THE PROJECT AREA 

4.5.1 Siang Group 



Jain et al. (1974) introduced this term to designate high to low grade 

metamorphic rock (= the metamorphic series; Coggin Brown, 1912) 

exposed over vast area of the ESB (Eastern Syntaxial Bend) but did not 

propose a classification. The term has been restricted to only katazonal 

high-grade rocks, which have distinct deformational and metamorphic 

characteristics and thus are easily differentiable from the low to medium 

grade metamorphic of the Siyom Group. 

The Siang Group of rocks occurs as a linear belt between the Tuting 

Granite/Tuting Metavolcanics in the north and the Siyom Group in the 

south with thrusted contacts. Its maximum development has been noted 

in the Siyom valley. Litho-succession of various unit of the Siang Group is 

shown in the Table-4.2. 

Table-4.2 Lithostratigraphy of the Siang Group 

(After, S.Singh, 1993). 

Group Formation Siyom Valley 

S 

I 

A 

N 

G 

G 

R 

O 

U 

P 

Yang Sang Chu Not exposed. 

Singing 

Pari Mountain 

Sillimanite-Garnet schist, quartzite, 

amphibolite and marble. 

Quartzite with minor biotite + garnet 

schist. 

Augen gneiss, biotite + garnet gneiss, 

Sillimanite +garnet gneiss and 

migmatite. 

The area of proposed dam site and powerhouse comprises predominantly 

of rock of Pari Mountain Formation of Siang Group. 

18

4.5.1.1 Pari Mountain Formation 



The Pari Mountain Formation comprises of very competent rock, and is 

widely jointed. Thus, it results in presence of huge boulders in the slope 

wash material and riverbed where this formation is present. 

The Pari Mountain Formation is represented by varieties of gneisses 

and migmatites. In the western part of the ESB, the augen and biotitegarnet 

gneiss, sillimanite gneiss and migmatites are widespread and best 

exposed along the Yapick-Tato section in the Siyom valley. 

Upstream of Row village (about 800m upstream of Sigik nala) high-grade 

metamorphic rocks of Pari Mountain Formation of Siang Group are 

thrusted over the Siyom Group by Siyom Thrust. Pari Mountain 

Formation is present upto Tato along the road section upstream of Siyom 

river. The rock types encountered in the project area are augen/biotite 

gneiss and migmatites. 

4.6 LINEAMENT 

State Remote sensing Application Center, Itanagar, on the basis of 

satellite imagery interpretation have traced number of lineaments within 

the area. In this region there are mainly two sets of lineaments, one is 

trending N-S and another trending NE-SW in correlation with the Eastern 

Syntaxial Bend. 

4.7 GEOMORPHOLOGY 

The Siyom river flows towards east along a series of rapids through 

mountainous terrain. In its journey, it is joined by number of intermittent 

and perennial nalas. The Siyom flows through steep narrow V-shaped 

valley. The geomorphic features of this region are results of orogeny and 

denudation process. The major geomorphic elements of the region are as 

under: - 

19

a) Steeply sloping structural mountains. 

b) Moderately sloping structural mountains. 

c) Structural valley. 

d) Narrow structural valley. 

e) River terrace. 



Steeply sloping and moderately sloping structural mountains have been 

divided based on the contour spacing. The mountains, which are sloping 

more than 50%, are termed as steeply sloping structural mountains and 

rest of them are moderately sloping structural mountains. 

The course of river and nalas in the young orogenic belt are governed by 

structural features such as joints, fractures, folds, faults etc. Hence the 

major valleys are termed as structural valleys and minor one as narrow 

structural valleys. A dendritic type of drainage pattern is developed in the 

Siyom basin. 

The area exhibits rugged topography having moderate to steep slopes. 

The river level is EL 710M and the highest elevation around the site in EL 

2000M. 

4.8 OVERBURDEN GEOLOGY 

The area around the dam site is mainly steeply to moderately sloping and 

at some places cliffs are present. The steep sloping area are mainly rocky 

or with thin veneer of overburden. Moderately sloping area is covered by 

either residual soil or slope wash material. River borne material is present 

along or near the river channel and river terrace. It is mainly composed of 

boulder of quartzite, gneisses, volcanic etc in sandy matrix. Apart from the 

river borne material, nala fan deposits are also present at the mouth of 

Perennial nala. In the project area, where Pari Mountain Formation is 

present, the slope wash material contains huge boulders of gneisses and 

migmatites. 

20

4.9 GEOLOGY AROUND PROJECT STRUCTURES 

4.9.1 Dam 



Owing to rock exposure on both the abutment and relatively less width of 

river section. The proposed dam site is located at N28º31'10", 

E94º30'25". The river has cut V-shaped symmetrical valley at this 

location refer Plate 4.1. The site is connected with a motorable road on 

right bank from Kaying to Tato and is approximately 58km. from Kaying. 

4.9.1.1 River Bed 

The water level in the river(during the month of September, 2003) is 

approximately +710m and width of the river is 70m. The river is flowing 

from the West to East direction. The bearing of left bank from right bank is 

N352º. The thickness of river borne material in the riverbed is anticipated 

between 10-12m and consists of sub rounded to rounded boulders, 

cobbles, pebbles mixed with medium-grained river sand. 

4.9.1.2 Right Abutment 

From road, the slope is gentler down to EL 830M. From that elevation 

down to riverbed level, the slope is steeper. 

At the right bank slope, rock outcrops are exposed from river water level 

upto EL 730M, and again, at an elevation of 800-820m, 870-880m and at 

the road cut. Rock outcrops shows very thickly to moderately foliated, 

strong to very strong, almost fresh biotite/augen gneiss, which is very 

hard and compact. The average orientation of foliation plane is 310º -320º 

/45º-52º i.e. upstream dipping. The thickness of the slope wash material 

vary from 10-15m and comprises of boulders of augen gneiss, biotite 

gneiss, quartzite of different size mixed with fine to medium grained 

yellowish clayey soil. 

21



Table-4.3 : The major joint sets encountered are as follows 

Joint 

set 

4.9.1.3 Left Abutment 

Attitude Persistence 

Spacing Condition 

S1 300º - 320°/ 35° - 58° 1m to >3m 10 to >60cm Tight 

S2 175°/60° 2m to >5m 20 to >60cm Tight to 

P.Open 

S3 225°/85° 1m to >3m 40 to >100cm Tight 

The left bank is less vegetated and exhibits more rock exposure. The 

average slope angle from riverbed upto EL: 910M varies between 45º 

to50º and above EL 910M, the slope is very steep. 

At the left bank slope, rock outcrops are exposed from river water level 

upto EL 720M and again at an EL of 750-780M, 805-835M and 905 to 

950M. The rock outcrops shows hard and competent biotite gneiss and 

foliation trending 300º -320º/40º-50º i.e. upstream dipping. The thickness 

of slope wash material is anticipated to be 10-12m. The slope wash 

material comprises of angular to sub angular rock fragments mixed with 

fine to medium grained, clayey/silty soil. 

4.9.2 Intakes 

The intake structure will be housed over the very hard, compact, slightly 

weathered to almost fresh biotite/gneiss, which is thickly foliated. 

4.9.3 Power Tunnel 

As per CEA layout, there was a proposal for power channel of about 9km 

length. After site visit, the layout has been modified and it is proposed to 

have a power tunnel having length 6.5km as shown in the layout. The 

power channel is proposed to be replaced by power tunnel due to 

following reasons: - 

22



1. The proposed 9km power channel is likely to encounter at least 

four perennial nalas and small as well as big slides. Therefore, 

open channel will not be feasible. Further, the area is thickly 

vegetated and would require lot of forest clearance for constructing 

power channel and maintenance there off. 

2. Viewing the very hard, competent gneissic rock and very good rock 

cover, tunnel will be a better option. 

3. The anticipated cover over the tunnel varies from 80 to 600m. 

4.9.4 Surge Shaft/Pressure Shaft 

The Surge shaft will also be housed in thickly to moderately bedded 

augen/biotite gneiss belonging to Pari mountain formation of Siang 

Group. 

4.9.5 Power House/Tail Race Channel 

The location of the proposed powerhouse has been shifted by 3.5km 

towards upstream side since CEA proposal was to fix powerhouse at EL 

470M or so. 

NHPC has already submitted detailed project report of Siang Middle 

Project on river Siyom for a 190m high Concrete face Rock fill Dam 

(CFRD) near village Raying. Construction of about 190m high CFRD 

across river Siyom would create a reservoir with FRL at EL: 510M and 

Maximum Water Level (MWL) at EL520M on account of flood mitigation. 

In the light of upcoming Siang Middle H.E. Project, the Naying 

powerhouse with tail water level at EL: 470M will be submerged, hence, it 

is proposed to shift the location of Powerhouse by about 3.5km upstream 

with tail water level at 520m. Underground powerhouse will be best 

suitable seeing the site condition. 

23



The entire slope below the road level is covered with slope wash material, 

consisting of boulder / rock fragments of different size, mixed with fine to 

medium sandy/clayey soil. The entire area / slope has a very luxuriant 

vegetation cover. The thickness of the slope wash material is anticipated 

to be 12-15 m. The road cut shows exposure of moderately thick to thickly 

foliated augen/biotite gneiss, which are slightly weathered, very hard and 

compact in nature. The tailrace shall also encounter the same rock type of 

Pari Mountain Formations of Proterozoic age. 

Table-4.4 : The major joint sets encountered in Power House 

area are as follows: 

Joint 

set 

4.10 Seismicity 

Attitude Persistence 

Spacing Conditi 

on 

S1 300º - 320°/ 35° - 58° 1m to >3m 10 to >60cm Tight 

S2 175°/60° 2m to >5m 

20 to >60cm Tight to 

P.Open 

S3 225°/85° 1m to >3m 40 to >100cm Tight 

The project area lies in the seismic zone V as per seismic zoning map of 

India as incorporated in Indian Standard, criteria for Earthquake Resistant 

Design of Structure IS: 1893(Part-I); 2002: Generl provision & buildings. 

The zone is broadly associated with a seismic intensity of IX on modified 

Mercelli Scale (M.M. Scale). 

State Remote Sensing Application Center- Itanagar, on the basis of 

satellite imagery interpretation have traced out number of lineaments 

within the vicinity of project area. The main structural features of project 

area is Siyom Thrust trending NS which lies about 3 km downstream of 

Powerhouse area .The Siyom Thrust separates the low grade 

metamorphosed Middle Proterozoic sequence (Rumgong Formation) from 

high grade metamorphosed Lower Proterozoic sequence (Pari Mountain 

Formation). 

24



Among important faults, the most important is the Gatte fault trending NE- 

SW, which is abutting in Nabung nala on left bank of river Siyom & no 

visible indication of shearing or faulting is seen on the road section. 

Another fault viz. Nabung fault, which is also trending NE-SW, lies about 

1km upstream of proposed dam axis. 

Apart from satellite imagery studies, these major tectonic & linear features 

require further field investigation to ascertain its actual presence on 

ground. 

4.11 CONCLUSION 

The scheme as such is an attractive proposal on following considerations: 

Rock strata likely to be encountered is augen/biotite gneisses of Pari 

Mountain Formation of Siang Group belonging to Proterozoic age. 

The rocks are very thickly to moderately foliated, slightly weathered 

and may not pose any serious problem during construction of the 

project. 

Siang (Middle) HE Project 1000MW has already been investigated 

and Detailed Project Report submitted. Assuming that this Project is 

approved for construction, it can be taken that all necessary 

infrastructure facility shall be available within close proximity. 

Since in the original proposal tailrace level was planned at + 470m, 

which will be submerge due to reservoir of Siang (Middle) HE 

Project. The shifting of proposed power house by approx 3.5 kms 

upstream, project will loose head of approx 60m, which could be 

achieved to some extent by 

Shifting of proposed dam by 400m and 

Increasing the height of the diversion dam. 

The height of dam could very well be increased since there is no 

agricultural land, which will be submerged. 

25



In view of the inaccessibility to the project area, the geophysical 

exploration could not be taken up. However, such exploration, if 

required, will be done at the time of DPR preparation. 

− There is no village/habitants in the proposed submergence since 

most of the hutments are located around the roadside only. 

− The proposed project is connected to Along, district headquarter of 

West Siang District by the road, which is maintained by Border 

Road organizations. 

4.12 CONSTRUCTION MATERIALS 

The valley being narrow, there is no river terrace/shoal deposit visible in 

the vicinity of the project along either bank of the Siyom river. 

For constructions of the proposed dam/diversion structure and other allied 

structure at Naying dam site, the requirement of coarse and fine 

aggregate can be met from the rock quartzite/biotite/ muscovite gneiss 

deposits along the road on right bank on the upstream side of dam axis. 

On left bank, the rock is exposed at many places but the face is almost 

vertical and it may not be possible to develop any quarry along that bank. 

For Power Channel/HRT, also the requirement of coarse and fine 

aggregate can be met from the rock deposits along the road on right 

bank. 

For power House, Tail Race etc. the excavated rock from Power House 

cavern on the right bank may be found suitable. Otherwise rock deposits 

along the road on right bank near power house site/Row may be utilized. 

For clayey soil (Impervious material) the material of two flat terraces 

under cultivation, one of approx. size 180x80m along the left bank of 

Siyom river just below Lipo village, while other of approx. size 

26



400x100m,42.0m above river water level along the right bank, below 

Yapik village 3.5 km upstream of dam site are the only clayey soil deposit. 

Other source is a clayey soil deposit at around EL 1600M a top the hill on 

left bank of Siyom river. Some small patches of brownish clayey soil are 

also visible just downstream of Yapik village 6.0 km u/s of proposed dam 

site. 

27

CHAPTER – V 

HYDROLOGY

5.0 GENERAL 

CHAPTER – V 

HYDROLOGY 



Naying H.E project is a run of the river scheme, proposed on Siyom river, 

a right bank tributary of river Siang, to harness the hydel potential of river 

Siyom. The project envisages construction of a 100m high diversion 

structure, about 6 Km upstream of confluence of Sike river with Siyom. 

The hydrological investigations and analysis have been carried out for 

Naying Project with a view to: 

• Assess the availability of water for power generation by 

establishing a series of average 10-daily discharges for the project 

site. 

• Establish the spillway design flood 

• Determine the capacity of the reservoir and the area of 

submergence at different levels including FRL and MDDL. 

5.1 River System and Basin characteristics 

Siyom river is one of the major tributary of Siang river and offers vast 

potential for hydropower development. It meets river Siang at Pangin, 

about 74km u/s of Passighat. River Siang is a major tributary of 

Brahmaputra and contributes about 33% of the total discharge of river 

Brahmaputra. 

River Siyom originates from Tunokar Ogo and subsequently flows 

southward till it takes a right angle turn near Yare. The river rises in 

mountainous terrain and has numerous tributaries along its entire reach. 

Some of the major tributaries of Siyom are Shir river, Site river, Shichu, 

Sike river and Sitin nallah. The Sike river is a major left bank tributary of 

Siyom river and joins about 10km upstream of Middle Siang dam site. The 

28



total length of the river from origin upto proposed dam site is about 69km 

and the distance from proposed dam site upto Middle Siang dam site is 

about 27 km. 

The area has a rugged terrain and the river has a steep gradient upto its 

confluence with Shichu nallah. Even downstream of this confluence, the 

gradient is equally steep with number of rapids. The area is covered with 

thick and dense forests. The basin is bounded on the north by Eastern 

Himalaya, on the west by Abore hills and Subansiri basin, on the east by 

Mishmi hills. 

5.1.2 Catchment Area 

The catchment area of the proposed scheme lies between Longitude 

93 o 45′00” E to 94 o 33′00” E and Latitude 28 o 25′00” N to 29 o 00’00” N. The 

catchment area upto the proposed dam site is about 2756 Sq. km. The 

proposed diversion structure is at Longitude 94 o 30′25” E and latitude 

28 o 31′10” N. The deepest riverbed elevation at the proposed diversion 

structure is about 710m. The catchment Plan of the proposed scheme is 

shown in Plate-5.1. 

The catchment plan is prepared from the catchment plan of Middle Siang 

H.E project given in the DPR submitted by NHPC. The catchment of 

Middle Siang was prepared on the basis of 1:50000 Survey of India 

toposheets. 

5.1.3 Temperature and Humidity 

The climate in the region is fairly humid and moist. The abrupt variation in 

altitude is chiefly responsible for abrupt changes in the climatic conditions 

and aided by the complex orography, the area experiences frequent 

rainfall of varying intensity and duration. The maximum temperature 

recorded is 27.3 0 C and minimum (-) 8 0 C at Ziro and the relative humidity 

29



varies from 62% to 94%. The basin experiences extreme cold 

temperatures during winter months. Temperature and relative humidity 

observations are being made in the basin at Kaying since February 2001, 

which lies near the Middle Siang dam site, for which NHPC has submitted 

the DPR. 

5.1.4 Precipitation Characteristics 

The climate of Siang Middle basin may be described as tropical monsoon 

climate. The southwest monsoon normally enters Assam and adjoining 

areas around the end of May, establishes firmly over the entire northeast 

India by the end of June. It withdraws from this region in the second 

week of October. During the four monsoon months of June to 

September, different low-pressure systems like depressions, cyclonic 

storms, etc. originating in the Bay of Bengal when they cross the Indian 

coast, sometimes move in an easterly to north -easterly direction causing 

heavy rainfall over the basin. 

It is to be mentioned here that there is considerable thunderstorm activity 

in this region in the month of May and the rainfall caused by these 

thunderstorms about 33.8 cm, (Pant et al.1970) is comparable in 

magnitude to the rainfall of any of the monsoon months. 

The mean annual rainfall over the basin as a whole has been worked out 

to be of the order of 269 cm and the mean seasonal rainfall over the basin 

is 218 cm (IITM, Pune). It is seen that about 81% of the annual rainfall 

has been received during the monsoon season of May to October and 

maximum precipitation has been found to occur during the month of June 

to August. The average maximum annual rainfall over the basin varies 

from 350 cm to 200 cm while the mean seasonal rainfall varies from 250 

cm to 150 cm. It is also seen that stations located to the south east of 

Siang Middle basin, i.e. Passighat and Denning recorded heavy rainfall, 

whereas rainfall slowly decreases towards Siang Middle basin. 

30



The heavy rainfall in the catchment is usually associated with the 

following synoptic situations : 

(i) Break monsoon situation or when the axis of the seasonal trough 

shift to the north from its normal position and lies close to the 

foothills of the Himalayas. 

(ii) Movement of depressions from Bay of Bengal towards eastern side 

of Assam. 

(iii) Formation and movements of land lows or land depressions over 

North-East India. 

5.1.4.1 Rain Gauge Network 

IMD has established the first rain-gauge station in Siang basin in 1916 at 

Passighat primarily for flood control work. Gradually more rain-gauge 

stations have been installed in the Siang Basin by different departments. 

Although the rain gauge network in Brahmaputra basin has not reached 

the international standard, efforts have been made continuously to 

improve and a fairly useful network of meteorological stations has been 

established. At present there are 26 rain-gauge stations in and around the 

Siang river catchment in India. There are seven ORG & SRRG rain 

gauge stations in and around Siang Middle Basin namely Tato, Mechuka, 

Monigong, Along, Kaying, Raying and Daring. NHPC is keeping records 

of rainfall data at all the above stations except at Tato. The previous 

rainfall data is also available as collected from Brahmaputra Board at all 

the above-mentioned stations except Kaying and Raying. The present 

network density comes out to one rain gauge for every 821 sq. km for 

Siang Middle catchment. The WMO have recommended roughly one rain 

gauge for every 500 sq. km in the plain area and one rain gauge for every 

150-250 sq. km for hilly area. Difficult terrain with lack of round the year 

access facilities is the main constraint for establishing the rain gauge 

31



stations as per network design requirements. The existing rain-gauge 

stations in the catchment have been listed in Table 5-1. 

Table 5-1 

S.No Name of station Period of data availability 

1. Mechuka Jan 59 to May 2003 

2. Monigong Jan 94 to May 2003 

3. Raying Apr 2000 to May 2003 

5.2 WATER AVAILABILITY STUDY 

5.2.1 Stream flow and River gauges 

River gauges have been established since 1949 on Siang river system. 

The first Gauge-Discharge station was established at Passighat on Siang 

river in 1949 and measurements are taken regularly upto 1962. 

Discharge observations for a period of 12 years from 1963 to 1974 were 

discontinued at Passighat. About 2 km upstream of Passighat one more 

gauge-discharge site was established at Ranaghat and daily 

measurement Gauge-Discharge were started from January 1978. No 

hourly gauge records at these two gauge discharge sites had been 

supplied by Brahmaputra Board to NHPC. On Siyom river, Brahmaputra 

Board had established a G&D site at Pangin. The gauge-discharge data 

at Pangin G&D site is available for the period of 1978 to 1994. Pangin is 

situated near the confluence of river Siyom with Siang river, about 72 km. 

downstream of the Middle Siang dam site. Presently NHPC has 

established a G&D site about 600m upstream of the proposed Middle 

Siang dam site, which is operational since May 2000. Velocity 

observations at this site are being done by float method. 

The various G&D sites and period of data availability in and around Siyom 

Basin is shown in Table 5-2. 

32



Table 5-2 : Table showing Location of G&D site 

S.No Name of site River Period of availability 

1. Pangin Siyom Jan 78 to Dec 1994 

2. Ranaghat Siang Jan 78 to May 98 

3. Middle Siang dam Siyom May 2000 to May 2003 

5.3.2 Present Study 

For the pre feasibility study, water availability for the proposed project has 

been computed on the basis of the water availability study done for Siang 

Middle H.E project. Water availability study for Siang Middle has been 

performed using the observed discharge data at Pangin and Ranaghat 

G&D site. The missing data at Pangin has been generated on the basis of 

regression equation developed between observed discharges at 

Ranaghat and Pangin for the common period. The average 10-daily 

series developed at Middle Siang dam site for the period Jan 1978- May 

2003 is then converted at Naying dam site using catchment area 

proportion. The catchment reduction factor has been worked out as 0.84. 

Average 10-daily series at the proposed dam site is enclosed as 

Annexure-I. After establishing G&D site near the proposed dam site with 

proper rain-gauge network in the basin, detailed water availability study 

shall be conducted in feasibility stage. 

5.3 RESERVOIR ELEVATION AREA CAPACITY CURVE 

The reservoir elevation-area-capacity curve for Naying project has been 

prepared from 1:50000 Survey of India toposheets. The contours are 

available at an interval of 40m the minimum contour being of 720m. The 

area enclosed within the contours has been found using Autocad. Area 

33



has been found from elevation 720m to 840m at an interval of 40m. The 

volume between any two elevations is calculated using the formula : 

V = H * (A1+A2+√A1A2)/3 

Where 

V = Volume between two contours 

H = Contour interval 

A1 = Area at level of first contour 

A2 = Area at level of second contour 

The incremental volumes thus computed are added up to obtain 

cumulative volume. The resultant area capacity curve is enclosed as 

Figure-I. The curve may be improved after receiving toposheets in scale 

of 1:25000 or reservoir cross-sections, during feasibility stage. 

5.4 DESIGN FLOOD 

The project envisages construction of about 100 m high dam across 

Siyom river. Since the height of the dam is more than 30 m. Therefore, as 

per IS 11223:1985, the spillway has to be designed to negotiate Probable 

Maximum Flood (PMF). 

Design Flood for a project can be estimated by following approaches: 

(i) Deterministic approach using Unit Hydrograph technique. 

(ii) Statistical approach using Flood frequency analysis 

(iii) Empirical methods 

• Unit Hydrograph technique 

Due to non-availability of G&D data and hourly gauges, design 

storm values in the proposed catchment, rating curves and 

observed flood hydrographs could not be developed for 

computing the Unit Hydrograph and Design Flood hydrograph. 

34

• Flood Frequency analysis 



Due to non-availability of long term, consistent G&D data 

near the proposed scheme, frequency analysis could not be 

done to estimate the design flood. 

• Empirical Methods 

(i) Creager’s formula 

The following empirical relationships have been used to 

estimate the design flood peak: 

0.894(0.386A)^ (-0.048) 

Qm = C1 (0.386A) 

Where C1 = 130 usually (adopted=130) 

A = Catchment area in sq. km = 2756 sq. km 

0.894(0.386*2756) ^ (-0.048) 

Therefore, Q = 130 (0.386*2756) 

= 11234 cumec 

(ii) Ali Nawab Jung formula 

Q = C(0.386A) (0.925-1/14log0.386A) 

Where C = 49 to 60 (60 used) 

Q = 60* (0.386*2756) (0.925-1/14log(0.386*2756)) 

= 8386 cumec 

(iii) Computation of Design Flood from Design Flood at Middle 

Siang using Dicken’s formula 

The design flood recommended for Middle Siang H.E project, 

having a catchment area of 3285 sq. km is 13500 cumec (2-day 

PMF). Naying project is located upstream of Middle Siang on 

Siyom river itself and catchments of both the projects are 

hydrologically and hydro-meteorologically similar. Therefore, it 

seems logical to transpose the design flood value of Middle Siang 

to proposed dam at Naying. This transposition has been done by 

35



Dicken’s formula using a conversion factor of 0.877. (Catchment 

area for Naying being 2756 sq. km) 

Q Naying = Q Siang Middle X (A Naying/A Siang Middle) 0.75 

= 11834 cumec 

A comparative study of flood peak computed from various methods is 

placed as Table 5-3. For pre-feasibility stage study, a design flood of 

11500 cumec has been recommended at proposed dam site. 

Table 5-3: Comparison of various Flood Values 

S.No. Method used Design Flood 

(cumec) 

1. Creager’s Formula 11234 

2. Ali Nawaz Jung Formula 8386 

3. Transposition of Middle Siang Flood 

peak (2-day PMF) on the basis of 

Dickens formula. 

11834 

On availability of more data/information, design flood will be estimated by 

deterministic approach using unit hydrograph technique and probabilistic 

approach using flood frequency analysis in feasibility stage. 

5.5 SEDIMENTATION 

The entire Siyom river basin belongs to Sibalic age and its entire surface 

is covered with thick vegetation and dense forests. Soil is mostly clayey 

or clayey - loom. Sand stone rocks are present under this soil coverage. 

Moreover, the soil in certain areas of the basin is quite sandy containing 

considerable amount of mica. Due to heavy precipitation during the 

monsoon the topsoil coverage varying from lighter material to heavier, 

including debris are washed away by the flood resulting from the 

precipitation, and finely these materials are deposited as sediment all 

along the river course. 

NHPC has started silt observations at Middle Siang Dam site from July- 

2000 in terms of coarse, medium and fine. The Punjab bottle type 

36



samplers are used for collections of sediment from river at a depth of 0.6 

D, where D is depth of water in the river. 

A rate of sedimentation of 0.141 Ham/Sq. km/Year (including 20% bed 

load) has been worked out for Middle Siang project based on suspended 

sediment observations at its dam site. This silt rate may be adopted for 

Naying project also. 

Detailed sediment study will be done during feasibility stage with more 

observed data at the proposed site using a suitable method. 

5.6 RECOMMENDATIONS FOR FUTURE STUDIES 

The following are the improvements suggested for feasibility /DPR stage 

study: . 

• Proper raingauge network along with Gauge-discharge-sediment 

observation sites on Siyom river near the proposed dam axis need be 

established before taking up preparation of feasibility report /DPR. 

• After establishing gauge and discharge site on Siyom river with 

proper raingauge network in the basin, detailed water availability 

study need be conducted in feasibility/DPR stage. 

• The reservoir elevation area capacity curve need be revised after 

availability of reservoir cross-sections or 1: 25000 scale contour maps 

in feasibility/DPR stage study. 

• On availability of more data/information, design flood need be 

estimated by deterministic approach using unit hydrograph technique 

and probabilistic approach using flood frequency analysis in 

feasibility/DPR stage. 

• Detailed reservoir sedimentation study need be done during 

feasibility/DPR stage with observed data on Siyom river at the 

proposed dam site using a suitable method. 

• The observations of CWC along with reply of NHPC have been 

enclosed in Appendix VII &VIII respectively and need be referred 

during feasibility/DPR stage. 

37

S.No 

Elevation 

(m) 

Area 

(sq.km) 

Capacity 

(Mcum) 

1 710 0.00 0.00 

2 720 0.08 0.26 

3 760 0.95 17.51 

4 800 1.75 70.66 

5 840 2.84 161.68 

6 880 4.10 299.80 

Elevation (m) 

NAYING H.E PROJECT 

RESERVOIR ELEVATION AREA CAPACITY CURVE 

880 

860 

840 

820 

800 

780 

760 

740 

720 

300.00 

270.00 

240.00 


Reservoir Elevation Area Capacity curve 

210.00 

Capacity (Mcum) 

180.00 

150.00 

120.00 

700 

700 

0.00 0.30 0.60 0.90 1.20 1.50 1.80 2.10 2.40 2.70 3.00 3.30 3.60 3.90 4.20 

Area (Sq.km) 

90.00 

60.00 

30.00 

0.00 

880 

860 

840 

820 

800 

780 

760 

740 

720 

Figure-I 

Elevation (m) 

38


AVERAGE 10-DAILY DISCHARGE 

Annexure-I 

YEAR/ 

MONTH 

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC AVG 

I 118.61 70.30 100.38 191.41 429.29 513.55 600.55 623.56 563.83 459.09 229.87 152.99 

1978 II 102.36 74.09 94.73 267.42 554.88 741.40 692.05 446.17 744.05 304.88 186.18 132.78 356.50 

III 61.10 90.86 105.26 425.68 595.11 1096.47 641.62 242.08 585.49 253.54 225.88 116.46 

I 96.44 79.14 104.11 158.10 386.85 709.53 1621.53 580.76 906.92 838.91 191.78 139.21 

1979 II 87.56 67.21 107.02 181.21 337.49 965.89 1168.28 423.57 896.09 508.65 147.83 119.41 426.40 

III 86.89 101.72 147.81 193.52 228.96 1070.79 1050.86 824.79 402.48 174.10 127.10 117.92 

I 116.23 123.13 247.80 212.08 409.27 607.72 701.59 1305.70 448.30 454.53 188.42 131.19 

1980 II 94.56 108.59 191.58 309.15 413.86 883.98 726.43 1821.27 481.73 318.81 145.99 89.01 408.59 

III 100.72 111.01 194.22 450.56 342.09 666.64 643.40 635.32 522.24 311.61 120.69 79.77 

I 99.16 83.15 117.15 119.92 227.98 409.73 983.20 818.38 798.09 612.01 253.06 157.41 

1981 II 86.35 87.96 111.25 119.86 313.42 529.80 1019.70 878.38 804.66 479.83 191.79 172.51 390.56 

III 85.23 99.02 105.19 131.21 424.03 783.16 684.56 892.91 636.53 409.86 176.99 156.76 

I 139.65 78.63 111.17 174.26 259.58 446.75 562.83 765.71 641.37 613.64 274.00 228.42 

1982 II 121.04 79.22 119.36 178.78 338.27 578.47 716.42 557.42 875.43 474.23 160.93 146.15 373.24 

III 87.27 89.36 128.53 168.68 334.45 646.93 1143.96 729.91 745.25 463.02 132.71 124.74 

I 104.73 96.57 112.79 182.43 317.10 504.13 451.65 491.51 629.54 358.14 188.41 108.43 

1983 II 99.40 92.47 153.68 290.87 415.06 372.23 391.69 500.20 773.63 467.65 168.45 96.78 319.83 

III 93.79 129.93 192.52 240.94 486.40 460.96 660.87 520.70 803.66 311.16 132.66 112.80 

I 97.98 92.49 87.87 318.14 424.80 564.13 917.01 745.60 555.72 393.16 453.29 186.65 

1984 II 97.81 87.62 87.32 440.72 535.66 972.62 1119.53 422.74 694.12 449.24 286.70 128.49 415.88 

III 84.60 86.16 114.30 383.03 662.56 766.23 981.78 518.35 419.97 451.74 245.88 97.60 

I 80.45 80.74 89.62 127.77 317.15 772.91 868.69 883.36 922.84 466.23 389.23 265.71 

1985 II 75.86 73.11 123.38 167.01 263.74 783.04 1138.68 962.71 869.97 422.19 355.82 228.71 451.13 

III 72.26 77.18 117.70 368.00 434.81 784.32 1026.62 1132.89 591.38 393.53 293.64 219.42 

I 193.04 118.34 114.40 111.12 191.50 414.79 519.31 1070.20 1015.76 608.39 161.02 130.14 

1986 II 173.53 111.61 117.90 138.50 302.60 607.67 501.11 908.51 1521.22 423.74 175.78 117.78 399.58 

III 150.37 119.81 102.61 228.75 344.56 675.42 564.66 1183.38 777.99 237.46 136.90 114.86 

39

YEAR/ 

MONTH 



Annexure-I 


I 74.82 61.01 85.03 190.07 245.71 1008.70 1893.37 2382.40 1227.73 610.02 307.08 161.76 

1987 II 69.73 59.31 98.62 387.31 336.85 1503.80 1293.15 2774.47 751.73 483.64 225.05 149.03 667.96 

III 64.95 81.67 73.33 358.06 573.78 1577.75 1920.68 1319.75 939.06 441.31 187.92 128.08 

I 112.96 89.71 96.85 163.33 230.05 374.44 1182.05 839.15 1763.60 1053.79 397.45 279.38 

1988 II 114.44 119.45 145.81 238.23 272.66 847.95 912.98 1740.60 1128.10 567.61 353.37 233.00 579.06 

III 104.87 244.50 177.26 288.21 533.99 816.10 1142.69 2166.99 1048.89 525.74 325.54 214.39 

I 304.02 205.58 208.49 240.61 554.39 653.25 1074.89 808.77 1013.95 819.61 499.96 380.15 

1989 II 283.92 212.36 245.22 284.94 502.97 818.10 1026.18 920.52 1031.46 684.73 482.79 368.28 578.34 

III 268.69 219.54 231.35 567.57 724.26 967.50 947.25 857.77 1021.77 558.25 464.25 367.05 

I 287.50 300.96 293.16 452.56 409.78 1118.24 973.24 1143.66 418.87 1225.22 476.43 357.92 

1990 II 264.83 268.21 291.90 429.55 396.45 1406.40 1042.70 950.87 411.38 1107.11 427.80 326.25 640.50 

III 258.65 297.05 366.21 518.30 918.59 1221.16 1528.01 553.18 1400.28 543.94 382.17 289.31 

I 272.40 249.75 312.77 564.33 836.27 879.20 1555.20 1096.76 851.59 578.95 375.56 288.68 

1991 II 266.76 250.73 348.35 695.09 807.65 785.44 1393.64 1045.27 653.84 648.24 364.30 285.45 627.25 

III 259.91 254.08 344.69 750.37 712.54 856.74 1123.31 1112.09 598.47 537.92 354.30 270.35 

I 237.02 252.90 206.04 324.65 507.51 739.87 1056.68 970.57 884.08 444.67 260.19 228.15 

1992 II 229.99 233.21 211.30 453.99 588.34 772.24 970.05 930.66 598.85 402.21 251.99 212.33 508.48 

III 236.28 225.65 287.90 459.05 700.12 1200.73 1025.35 984.97 444.29 335.67 234.20 203.55 

I 217.06 203.85 205.81 222.80 250.37 427.59 758.61 1011.22 1209.49 867.36 458.16 336.93 

1993 II 221.80 241.76 249.61 223.07 262.35 591.58 912.76 1195.47 1139.31 683.52 322.10 301.29 530.23 

III 212.32 225.04 253.50 255.40 252.94 720.81 1086.92 1328.51 1034.63 604.79 313.69 285.91 

I 262.62 214.38 222.37 237.67 516.36 882.97 957.79 813.22 638.62 471.03 419.03 346.97 

1994 II 245.55 221.94 198.22 300.21 689.83 940.73 933.87 860.38 579.60 476.75 361.91 324.97 513.98 

III 228.01 219.60 241.05 418.13 941.82 1003.68 874.92 757.22 532.04 478.80 369.40 321.69 

I 152.75 131.84 150.05 233.87 476.36 542.09 927.16 1018.00 1082.26 459.37 190.13 147.32 

2000 II 142.57 130.79 163.75 308.54 561.12 567.15 1157.91 986.46 1031.50 525.06 212.52 144.24 

III 134.89 147.50 183.41 378.85 753.08 519.03 847.48 990.48 854.11 363.46 173.47 120.69 

40

YEAR/ 

MONTH 



Annexure-I 


I 107.56 109.47 122.51 260.46 615.05 916.11 429.40 766.28 1103.16 487.86 218.77 104.94 

2001 II 89.50 86.96 102.92 517.91 624.18 571.78 1175.98 794.38 783.56 368.70 166.82 85.99 471.10 

III 102.41 123.21 153.53 379.21 699.63 1198.54 1157.59 1440.69 558.83 298.78 155.90 80.85 

I 72.28 68.98 83.84 152.88 337.03 393.57 955.48 517.25 316.67 451.14 174.33 91.97 

2002 II 72.23 77.84 126.16 312.05 375.79 559.79 635.66 657.92 404.57 284.00 163.85 78.44 343.64 

III 84.90 82.87 185.39 649.10 495.04 669.95 1474.61 416.49 524.72 243.77 103.39 77.11 

I 60.57 57.70 78.81 272.87 437.60 

2003 II 54.01 62.23 150.67 234.82 385.38 

III 54.50 71.77 145.76 343.20 385.30 

I 152.75 131.84 150.05 233.87 399.05 643.96 949.51 932.60 849.62 613.66 305.31 211.22 

AVG II 142.56 130.79 163.75 308.54 441.84 790.00 946.44 988.90 808.74 504.04 257.60 187.04 472.41 

III 134.89 147.50 183.41 378.85 549.72 885.14 1026.36 930.42 722.10 396.92 232.84 174.97 

41

CHAPTER – VI 

CONCEPTUAL 

LAYOUT & PLANNING


CHAPTER - VI 


Naying HE Project(4 X 250 MW) 

CONCEPTUAL LAYOUT AND PLANNING 

The Naying H.E. project is located in West Siang district of Arunachal 

Pradesh upstream of the proposed Middle Siang Project. It is a run of the 

river scheme with some storage proposed to harness hydel potential of 

the river Siyom, a tributary of river Siang. A maximum gross head of the 

order of 285 m between Dam site and Power House is proposed to be 

utilized for power generation. The powerhouse will have an installed 

capacity of 1000 MW. 

6.1 PROJECT COMPONENTS 

• Two nos. 9.0 m diameter, 500 m long Diversion Tunnels with u/s & d/s 

coffer dams. 

• 105 m high & 255 m long concrete gravity dam with a central spillways. 

• Two nos. Intake Structures 

• Two nos. 8.5 m diameter horseshoe shaped concrete lined 6.5 kms long 

Head Race Tunnels with three adits. 

• Two nos. 25 m diameter & approx. 120 m high semi-Underground Surge 

Shafts. 

• Two nos. steel lined circular Pressure Shafts of 7.0 m diameter, 300 m 

long which further bifurcate into 2 numbers steel lined circular penstocks 

of 4.6 m diameter 

• Underground Power House of size 135m x 22m x 44.5m consisting of 4 

Francis units of 250 MW each. 

• Two nos. 8.5 m diameter Horseshoe shaped tailrace tunnels of about 

500-m length 

Proposed General Layout Plan is enclosed as Plate 6.1. 

42

6.2 Dam and River diversion works 



The choice of location and type of the dam has been made keeping in 

view the topography, geology and maximum water availability. The IS 

code stipulates consideration of 1 in 100 yrs monsoon flood for diversion 

in case of embankment dam and 1 in 25 yrs non monsoon flood for 

concrete dam. Requirement of low level spillway for effective reservoir 

flushing ,high value of PMF necessitate the provision of concrete dam. 

Construction of 105 m high concrete Dam has been proposed across river 

Siyom considering 4 to 6 hours peaking. The reservoir formed by 

construction of Dam has a gross storage pre-sedimentation capacity of 

about 80 Mcum and live storage capacity of about 65 Mcum. After 

sedimentation, the reservoir is likely to have a live storage capacity of 

more than what is adequate for running the power station at full capacity 

for four to six hours in a day during the period of lean flows. 

Width of the valley at Dam site varies from 60 m at riverbed level to 255 m 

at EL 810 m. Average bed level at Dam site is EL +705 m. FRL is 

proposed to be fixed at EL 805 m and MDDL at EL.765 m keeping in view 

the inflow of water in Siyom during lean period. The top of the dam has 

been proposed at EL 810 m and seat of the dam is proposed to be kept at 

EL 705 m after removal of approx. 20 m thick overburden. Near the dam 

axis, botite / augen gneisses are exposed all along the road cut as well as 

along the nalla banks. The overflow section is 135 m long. and Non – 

overflow section is 130 m. 

The spillway for concrete gravity dam is proposed to be designed for a 

probable maximum flood (PMF) of 11500 cumecs. Keeping in view large 

quantum of silt being carried by river Siyom and high PMF, two level 

spillways are proposed. Five nos. lower level orifice type spillways are 

proposed with crest at EL 735.0 m having spillway opening size of 7.0 x 

43



7.3 m. Four nos. upper level orifice type spillways ( two blocks on either 

side of the toe level spillway ) are proposed with crest at EL 785 m with 

opening size of 9.0 m x 12.5 m. Spillway arrangements have provision of 

one extra bay to take care of non-operational bay. Total length of the 

spillway structure is 135 m. Two nos. Concrete lined 9.0 m diameter 

horseshoe shaped , 500 m long diversion tunnel has been proposed on 

the left bank of the river to divert a flood of approx.2000 cumecs of Siyom 

River. In order to divert the river during construction of the dam, an u/s 

coffer dam of approx. height 20m and d/s cofferdam of 10m height is 

proposed. Proposed Dam Complex General Layout, Dam Cross 

Section and Dam Upstream Elevation is enclosed as Plate 6.2, 6.3 & 

6.5 respectively. The comments of CMMD Directorate, CWC and reply of 

NHPC is enclosed as Appendix- IX. 

6.3 Power Intakes 

The proposed power intake system is on the right bank of the river and 

consists of two nos. power intakes. 

The invert level of the intake structure has been kept as 745 m taking into 

consideration the water seal requirement to prevent the vortex formation 

and air entertainment. Also, this level being 10m higher than the spillway 

crest, it shall ensure reduced entry of sediments in the water conductor 

system. The intake structure shall be provided with the trash racks to 

prevent the entry of trash in the water conductor system. 

6.4 Head Race Tunnels, Surge Shafts, and Pressure Shafts 

The proposed two nos. 8.5 m diameter horseshoe shaped concrete lined 

head race tunnels of 6.5 km length, are designed to carry a design 

discharge of 226 cumecs each. The diameter has been fixed keeping the 

velocity of water within 4.0m/s in the tunnel. Invert level of head race 

tunnel is fixed at EL. 745 m near intake. The rock cover above head race 

44



tunnel generally varies from +100 m to +600 m. The low cover reaches 

are confined to prominent nalla crossings. The HRT shall be aligned with 

in the rock type of biotite / augen gneisses , migmatite of Pari mountain 

formation of Siang group. Three nos. construction adits are proposed to 

facilitate excavation of headrace tunnel within the scheduled completion 

time. The tunnel is proposed to be lined with 500 mm thick plain M-25 

concrete. The rock support treatment shall consist of grouted rock 

bolts/anchors and shotcrete with or without wire mesh as per geological 

conditions encountered. 

Two nos. vertical simple type semi-underground surge shafts of 25 m 

finished diameter and about 120 m height have been proposed. Surge 

shafts are proposed to be concrete lined with 1.0 m thick R.C.C lining. Its 

bottom is kept at EL 730m at the HRT and surge shafts junction. The 

transient studies shall be required to work out the maximum and minimum 

levels for the worst conditions. 

Two nos. Steel lined circular Pressure Shafts of 7.0 m diameter and 300m 

length take off from the surge shafts which further bifurcate into 2 

numbers underground steel lined circular penstocks of 4.6 m diameter 

which will feed water to 4 units of Francis turbines each of 250 MW. 

6.5 Power House Complex & Tail Race Channel 

The underground Power House is located on the right bank of Siyom river 

upstream of proposed Middle Siang Project. It will have an installed 

capacity of 1000 MW ( 4 generating units of 250 MW each). The units are 

spaced at a distance of 20 m center to center. The center line of the 

turbine is proposed at about EL 514.5 m. The deepest level of the draft 

tube pit is at EL 501.9 m. One number electrically operated overhead 

traveling crane (E.O.T) of apprx.2 x 250 MT capacity shall be provided for 

handling of the equipment. The Main inlet valve chamber is proposed on 

the u/s of the powerhouse. The overall dimension of the Power 

45



House is length 135 m, width 22 m, and height 44.5 m. A Control block 

area shall be located on one end of machine hall. The Transformer 

cavern proposed 50m d/s of power house cavern of approx. size is 135 m 

x 18 m x 30 m. 

Cables from transformers will be taken to the pothead yard by a cable 

cum ventilation tunnel. A cable tunnel of size 6.0 m will take off from 

transformer area and shall carry cables to the pothead yard. The pothead 

yard shall measure about 150 m x 60 m, which shall be formed in 

cutting/filling. 

Water from the turbines is discharged back to Siyom river through four 

nos. draft tubes which merge into two tailrace tunnels of diameter 8.5 m. 

This tunnel is 500m long with invert at EL. 510 m at the outlet. The 

tailrace outlet level has been kept keeping in view the MWL of Middle 

Siang project which is 520.0 m. 

Proposed Downstream Underground Works General Layout &Water 

Conductor System L-Section is enclosed as Plate 6.4 & 6.5 

respectively. The comments of HCD Directorate, CWC and reply of NHPC 

is enclosed as Appendix- X. 

6.6 Further Studies 

6.6.1 Topographical Studies 

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

firm up the various components of the project. 

i) Reservoir Survey – 1:10,000 scale with contour interval of 10.and 

river cross sections at every 500m in the reservoir area. 

ii) Dam / Powerhouse area – 1:2,000 scale with 2m contour interval. 

iii) Headrace tunnels – 1:5,000 scale with 10 m contour interval. 

iv) Intake, Adit / tunnels Portal, Surge Shaft area and TRT outlet- 

1:500 scale with contour interval at 1m. 

46

6.6.2 Geological and Geo-technical investigations 



Geological / geotechnical investigations including surface mapping and 

subsurface explorations like exploratory drilling / drifting and seismic 

profiling at the dam and power house area. Rock mechanic lab 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 be required to be 

undertaken. 

6.6.3 Design Studies 

Hydraulic design of various structures like spillway, power intake, 

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. 

6.7 HYDRO-MECHANICAL EQUIPMENT 

6.7.1 General 

Following hydro-mechanical equipments have been envisaged for Naying 

HE Project: - 

6.7.1.1 Diversion Tunnel Gates and Hoists: 

For the diversion of water during construction stage it is proposed to 

provide two number horseshoe shaped diversion tunnels of 9.0 m 

diameter. The diversion tunnel inlet is divided into two openings. After the 

construction of the dam, for the purpose of plugging the diversion tunnel, 

two number fixed wheel type gate for opening size of 3.75 m x 9.0 m will 

be provided at inlet of each tunnel i.e. one for each opening. 

47



The gates shall be operated by means of electrically operated rope drum 

hoists of 90 T capacity. 

6.7.1.2 Upper Spillway Radial Gates, Hoists, stoplog and Gantry Crane: 

The upper spillway consists of four bays of opening size 9.0 m x 12.5 m 

with crest at EL 785.0 m. Four orifice type radial gates for opening size of 

9.0 m x 12.5 m shall be provided to control the discharge through the 

gated portion of the spillway. Each gate shall be operated by means of a 

hydraulic hoist consisting of two hydraulic cylinders of 150 T capacity 

each. The gate operation shall be done from a local control room as well 

as from remote control system located at the dam control room (DCR) 

with provision of gate position indication at Powerhouse. The operation 

from DCR shall be through a programmable computer based automatic 

reservoir measuring and control system located in the DCR. 

The inspection and maintenance of the radial gate shall be carried out by 

lowering one set of sliding type Stoplogs on the upstream side of these 

gates. The Stoplogs shall be operated under balanced head condition. It 

is proposed to operate the stoplogs by means of a common gantry crane 

of 150 T capacity provided for lower spillway on the top of the spillway 

deck 

The stoplog units will be stored in the storage vents provided in the dam 

area on both sides. 

One trolley mounted mobile gasoline engine powered power pack 

capable of operating one gate at 1/4 th of the normal rated speed is also 

envisaged. 

48



6.7.1.3 Lower Spillway orifice Radial Gates, Hoists, Bulkhead and Gantry 

Crane: 

The lower spillway consists of five orifice type bays of opening size 7.0 m x 

7.3 m with crest at EL 750.0 m. Five submerged type radial gates for 

opening size of 7.0 m x 7.3 m shall be provided for desilting operations 

and to pass the design flood discharge through the gated portion of the 

spillway. Each gate shall be operated by means of means of a hydraulic 

hoist consisting of two hydraulic cylinders of 150 T capacity each. The gate 

operation shall be done from a local control room as well as from remote 

control system located at the dam control room (DCR) with provision of 

gate position indication at Powerhouse. The operation from DCR shall be 

through a programmable computer based automatic reservoir measuring 

and control system located in the DCR. 

The inspection and maintenance of the radial gate shall be carried out by 

lowering a bulkhead gate on the upstream side of these gates. One 

number wheeled type bulkhead gate have been envisaged to cater to the 

maintenance requirement of 5 nos. spillway radial gates. Steel Liner shall 

be provided in the water passage at the bulkhead gate grooves. The gate 

shall have upstream skin plate and downstream sealing. It is proposed to 

operate the bulkhead gate by means of a gantry crane of 150 T capacity 

with the help of a lifting beam. A separate storage vent shall be provided in 

the non-overflow section at the deck level for storing the bulkhead gate 

when not in use. 

On the underside of breast wall provision has been kept for high strength 

steel liner. 

One trolley mounted mobile gasoline engine powered power pack capable 

of operating one gate at 1/4 th of the normal rated speed is also envisaged. 

49



6.7.1.4 Power Tunnel Intake Gate, bulkhead gate with Hoist, Trash Rack 

and Raking Machine: 

A fixed wheel type gate for opening size 7.0 m x 8.5 m shall be provided 

just downstream of the each intake bell mouth. The sill of the gate is 

located at EL 745.0 m. The gate shall be operated by means of dedicated 

electrically operated rope drum hoists of 240 T capacity located on the 

hoist platform installed over trestles. 

On upstream of the intake gate, provision has been made for one set of 

bulkhead gate for opening size 7.0 m X 8.5 m. It is proposed to operate 

the bulkhead by means of a 160 T capacity dedicated rope drum hoist. 

On upstream of the bulkhead an inclined trash rack (15° with vertical), 

shall be provided 

The cleaning of the trash rack shall be done by means of a trash-raking 

machine. 

6.7.1.5 Adit gates: 

Hinged type gates of suitable opening size has been proposed to be 

provided in the concrete plug at construction Adits to give access to the 

head race tunnel in the event of any inspection, repair and maintenance 

in future. The gates will be operated manually. 

6.7.1.6 Surge Shaft Gate 

For isolating the pressure shaft a slide type gate for opening size of 4.5 m 

X 5.0 m is to be provided at the inlet of each pressure shaft. The gates 

shall be operated by means of electrically operated rope drum hoists of 

65 T capacity. 

50

6.7.1.7 Draft Tube Gate: 



The draft tube emerging out from each generating unit gets divided into 

two bays each of size 3.8 m X 6.0 m. Each bay is provided with one fixed 

wheel type gate for the above opening to isolate the generating units from 

tail water. The gate will have an upstream sealing (pressure / tailrace 

side) and upstream skin plate. 

Each gate shall be operated by means of dedicated rope drum hoist of 35 

T capacity. 

6.7.1.8 Tail race outlet stoplogs: 

For the inspection and maintenance of the tailrace tunnels, one set of 

stoplog has been envisaged at outlet structure. The stoplog shall be 

designed for a head of corresponding to maximum Tail water level and 

operated under balanced head conditions. These stoplog shall be 

operated by means of a mobile crane. 

6.7.1.9 Pressure Shaft Liner: 

Two no. Pressure Shaft of dia. 7000 mm fully steel lined will take off from 

Surge Shaft to feed the turbine placed in the powerhouse. It comprises 

horizontal & vertical ferrules, 2 nos. vertical bends, 2 nos. plan bends, 1 

no. bifurcation and branch pipes for each pressure shaft to feed four 

turbines. 

The material of Pressure Shaft liner shall conform to ASTM A537 Class 

1and ASTM 517 GR F. However bifurcation material shall conform to 

ASTM A517 Gr. F. 

51

6.7.1.10 Miscellaneous: 

a) Reservoir measuring and Remote Control System 



One complete set of remote control system for the remote control 

operation of spillway gates, alongwith programmable computerized 

automatic reservoir monitoring control system is provided in the dam 

control room. The programmable reservoir monitoring and control system 

shall include all necessary instrumentation required for monitoring and 

control of reservoir including water level measuring systems, gate position 

indication transducers for spillway gates and intake gate discharge 

measuring devices. The indication of this system shall also be made 

available in the powerhouse. The communication system shall be through 

fiber optic cable. 

b) Diesel Generating Set 

A three-phase synchronous type diesel generating set of 500 KVA, 450 

Volts, 50 Hz is envisaged for the emergency operations of the HM 

equipments at the dam site. The diesel generating set shall be located in 

the dam area to provide back-up supply to gate operating equipments and 

to the computerized control system in case of power failure. 

52

CHAPTER – VII 

POWER POTENTIAL STUDIES


CHAPTER - VII 

POWER POTENTIAL STUDIES 



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

the basis of the discharge data for the year June 1978 to May 1994 & 

June 2000 to May 2003 (19 Years). Naying H.E. Project is located on 

Siyom river in West Siang district of Arunachal Pradesh. It is essentially a 

reservoir based scheme. The installed capacity of Naying project has 

been proposed as 1000 MW comprising of four units, each of 250 MW in 

the underground type power house. 

The salient features of the project are as follows : - 

Installed capacity = 1000 MW 

No. & size of unit = 4 units of 250 MW 

Type of power house = Underground type 

Net head = 245.0 meters 

Design discharge per unit = 113.2 cumecs 

Type of switchyard = 400 KV GIS 

Turbine type = Vertical Francis 

Speed of turbine = 214.3 rpm 

Generation voltage = 16 KV 

Transmission voltage = 400 KV 

GSU Transformer = 3 Nos, 102 MVA, Single-phase 

Energy generation in 90% 

dependable year with 95% = 4966.76 MU 

Machine availability 

53

7.1 AVAILABLE DATA 



The Power Potential studies have been carried out based on following 

data: - 

a) Discharge Data 

b) FRL, MDDL, TWL, Head losses and Area capacity curve. 

c) Due to non-availability of evaporation loss, evaporation loss has 

not been accounted for in the power potential study. 

7.2 Discharge Data 

Inflow series of 19 years i.e. 1978-1979 to 1993-1994 & 2000-01 to 2002- 

03 has been obtained and used for carrying out power potential and 

optimization studies. The 10-daily discharge data in cumecs for all 19 

years is shown in the enclosed Table-I. The criterion of 90% dependable 

flow is applied for conducting power potential studies and inflow of same 

is shown in Table-II. 

7.3 Fixation of Full Reservoir Level (FRL) 

The Full reservoir level has been fixed at EL. 805.0 m based on the 

following considerations : 

1) The river bed level at the dam site 

2) The height of dam above river bed 

A 100 m high dam is considered to include the following : 

i) A low level spillway to take care of sediments in reservoir 

ii) A live capacity of 55 MCUM to include storage in the spillway for 

providing firm power. 

iii) Avoiding the separate desilting arrangement in view of large 

design discharge of water conductor system. 

54

7.4 Fixation of Minimum Draw Down Level (MDDL) 



The MDDL level has been fixed at EL. 765.0 m, on the one hand keeping 

the power intake sufficiently above the low level spillways & on the other 

hand to provide sufficient water seal over the power intakes. The live 

capacity between FRL & MDDL is also taken into consideration while 

fixing both FRL & MDDL. 

7.5 Fixation of Tail water level (TWL) 

The Tail water level has been fixed at EL. 520.0 M keeping in view the 

FRL level and maximum water level of the Siang Middle reservoir. 

7.6 Operating Head and Head Losses 

Full Reservoir Level (FRL) and Minimum Draw Down Level (MDDL) are 

respectively at EL 805.0 m and 765.0m while the average tail water level 

corresponding to 4 units running has been taken as 520.0 m. Head losses 

in the water conductor system have been taken as 10% of the gross 

head. The net operating head for turbines has been calculated from the 

following formula, 

Net Operating Head: 

= MDD +2/3(FRL-MDDL) - Average Tail Water level–Head Losses 

Thus, by above-mentioned formula, the net operating head works out to 

be 245.0 m. 

7.7 Definition of terms 

7.7.1 90% Dependable Year 

This is the lower decile of the series of the corresponding monthly period 

of the record i.e. (N+1) x 0.90th year where N is the years for which 

55



hydrological data are available. 90% dependable year comes out to be 

2002-03 as shown in Table – III (a). 

7.7.2 Annual Design Energy 

This is the yearly energy generated during the 90% dependable year 

2002-03 with 95% machine availability, which works out to be 4966.76 

MU as shown in Table-IV. It may be seen from Table-III (b), that the firm 

power is 150.16 MW and corresponding load factor is 15%. Further, it is 

also mentioned that the load factor during monsoon i.e. March to 

November and lean period i.e. Dec. to Feb. are 71.47% and 16.68% 

respectively. 

7.8 Installed Capacity 

The installed capacity of Power house has been selected based on the 

following considerations: - 

• Assessment of the energy generation with various installed 

capacities. 

• Maximum utilization of the available inflow. 

• Incremental value of energy generation with the increased installed 

capacity. 

• Annual Load factor. 

The power potential study has been carried out for different installed 

capacities ranging from 600 MW to 3600 MW with an increment of 100 

MW, as shown in Table-V. Based on the above-mentioned parameters, 

the installed capacity of the power plant has been selected as 1000 MW. 

56

7.9 Size of Generating Units 



The power load demand in India is increasing at a very rapid rate, and 

both hydro electric and thermal (including nuclear) power potential in the 

country are being developed not only to meet the overall requirements, 

but simultaneously also to provide a proper hydro and thermal power for 

optimum operation of the system. Keeping this in view current practice is 

to opt for largest size hydro units permissible within the parameters of 

economy, operating efficiency, maintenance, optimum utilization of 

available water, transport limitations etc. Based on above-mentioned 

parameters, 4 No. Units of 250 MW each have been proposed for this 

project. 

7.10 Annual Energy Generation 

The restricted energy generations in the 90% dependable year i.e. (2002- 

03) are shown in the enclosed Table-IV. It may be seen from this table, 

that the total energy generation in 90% dependable year with 95% 

machine availability restricted to an installed capacity of 1000 MW is 

4966.76 MU. 

The comments of HP&I and SP&PA Divisions of CEA and reply of NHPC 

is enclosed as Appendix- VI. 

57

Month 

JUNE 

JULY 

AUGUST 

1978- 

1979 

1979- 

1980 

1980- 

1981 

1981- 

1982 

1982- 

1983 

1983- 

1984 

1984- 

1985 

1985- 

1986 

1986- 

1987 

1-10 513.55 709.53 607.72 409.73 446.75 504.13 564.13 772.91 414.79 1008.70 374.44 653.25 1118.24 879.20 739.87 427.59 542.09 916.11 393.57 

11-20 741.40 965.89 883.98 529.80 578.47 372.23 972.62 783.04 607.67 1503.80 847.95 818.10 1406.40 785.44 772.24 591.58 567.15 571.78 559.79 

21-30 1096.47 1070.79 666.64 783.16 646.93 460.96 766.23 784.32 675.42 1577.75 816.10 967.50 1221.16 856.74 1200.73 720.81 519.03 1198.54 669.95 

1-10 600.55 1621.53 701.59 983.20 562.83 451.65 917.01 868.69 519.31 1893.37 1182.05 1074.89 973.24 1555.20 1056.68 758.61 927.16 429.40 955.48 

11-20 692.05 1168.28 726.43 1019.70 716.42 391.69 1119.53 1138.68 501.11 1293.15 912.98 1026.18 1042.70 1393.64 970.05 912.76 1157.91 1175.98 635.66 

21-31 641.62 1050.86 643.40 684.56 1143.96 660.87 981.78 1026.62 564.66 1920.68 1142.69 947.25 1528.01 1123.31 1025.35 1086.92 847.48 1157.59 1474.61 

1-10 623.56 580.76 1305.70 818.38 765.71 491.51 745.60 883.36 1070.20 2382.40 839.15 808.77 1143.66 1096.76 970.57 1011.22 1018.00 766.28 517.25 

11-20 446.17 423.57 1821.27 878.38 557.42 500.20 422.74 962.71 908.51 2774.47 1740.60 920.52 950.87 1045.27 930.66 1195.47 986.46 794.38 657.92 

21-31 242.08 824.79 635.32 892.91 729.91 520.70 518.35 1132.89 1183.38 1319.75 2166.99 857.77 553.18 1112.09 984.97 1328.51 990.48 1440.69 416.49 

1-10 563.83 906.92 448.30 798.09 641.37 629.54 555.72 922.84 1015.76 1227.73 1763.60 1013.95 418.87 851.59 884.08 1209.49 1082.26 1103.16 316.67 

SEPTEMBER 11-20 744.05 896.09 481.73 804.66 875.43 773.63 694.12 869.97 1521.22 751.73 1128.10 1031.46 411.38 653.84 598.85 1139.31 1031.50 783.56 404.57 

OCTOBER 

NOVEMBER 

DECEMBER 

JANUARY 

FEBRUARY 

MARCH 

APRIL 

MAY 


DISCHARGE DATA 

21-30 585.49 402.48 522.24 636.53 745.25 803.66 419.97 591.38 777.99 939.06 1048.89 1021.77 1400.28 598.47 444.29 1034.63 854.11 558.83 524.72 

1-10 459.09 838.91 454.53 612.01 613.64 358.14 393.16 466.23 608.39 610.02 1053.79 819.61 1225.22 578.95 444.67 867.36 459.37 487.86 451.14 

11-20 304.88 508.65 318.81 479.83 474.23 467.65 449.24 422.19 423.74 483.64 567.61 684.73 1107.11 648.24 402.21 683.52 525.06 368.70 284.00 

21-31 253.54 174.10 311.61 409.86 463.02 311.16 451.74 393.53 237.46 441.31 525.74 558.25 543.94 537.92 335.67 604.79 363.46 298.78 243.77 

1-10 229.87 191.78 188.42 253.06 274.00 188.41 453.29 389.23 161.02 307.08 397.45 499.96 476.43 375.56 260.19 458.16 190.13 218.77 174.33 

11-20 186.18 147.83 145.99 191.79 160.93 168.45 286.70 355.82 175.78 225.05 353.37 482.79 427.80 364.30 251.99 322.10 212.52 166.82 163.85 

21-30 225.88 127.10 120.69 176.99 132.71 132.66 245.88 293.64 136.90 187.92 325.54 464.25 382.17 354.30 234.20 313.69 173.47 155.90 103.39 

1-10 152.99 139.21 131.19 157.41 228.42 108.43 186.65 265.71 130.14 161.76 279.38 380.15 357.92 288.68 228.15 336.93 147.32 104.94 91.97 

11-20 132.78 119.41 89.01 172.51 146.15 96.78 128.49 228.71 117.78 149.03 233.00 368.28 326.25 285.45 212.33 301.29 144.24 85.99 78.44 

21-31 116.46 117.92 79.77 156.76 124.74 112.80 97.60 219.42 114.86 128.08 214.39 367.05 289.31 270.35 203.55 285.91 120.69 80.85 77.11 

1-10 96.44 116.23 99.16 139.65 104.73 97.98 80.45 193.04 74.82 112.96 304.02 287.50 272.40 237.02 217.06 262.62 107.56 72.28 60.57 

11-20 87.56 94.56 86.35 121.04 99.40 97.81 75.86 173.53 69.73 114.44 283.92 264.83 266.76 229.99 221.80 245.55 89.50 72.23 54.01 

21-31 86.89 100.72 85.23 87.27 93.79 84.60 72.26 150.37 64.95 104.87 268.69 258.65 259.91 236.28 212.32 228.01 102.41 84.90 54.50 

1-10 79.14 123.13 83.15 78.63 96.57 92.49 80.74 118.34 61.01 89.71 205.58 300.96 249.75 252.90 203.85 214.38 109.47 68.98 57.70 

11-20 67.21 108.59 87.96 79.22 92.47 87.62 73.11 111.61 59.31 119.45 212.36 268.21 250.73 233.21 241.76 221.94 86.96 77.84 62.23 

21-28 101.72 111.01 99.02 89.36 129.93 86.16 77.18 119.81 81.67 244.50 219.54 297.05 254.08 225.65 225.04 219.60 123.21 82.87 71.77 

1-10 104.11 247.80 117.15 111.17 112.79 87.87 89.62 114.40 85.03 96.85 208.49 293.16 312.77 206.04 205.81 222.37 122.51 83.84 78.81 

11-20 107.02 191.58 111.25 119.36 153.68 87.32 123.38 117.90 98.62 145.81 245.22 291.90 348.35 211.30 249.61 198.22 102.92 126.16 150.67 

21-31 147.81 194.22 105.19 128.53 192.52 114.30 117.70 102.61 73.33 177.26 231.35 366.21 344.69 287.90 253.50 241.05 153.53 185.39 145.76 

1-10 158.10 212.08 119.92 174.26 182.43 318.14 127.77 111.12 190.07 163.33 240.61 452.56 564.33 324.65 222.80 237.67 260.46 152.88 272.87 

11-20 181.21 309.15 119.86 178.78 290.87 440.72 167.01 138.50 387.31 238.23 284.94 429.55 695.09 453.99 223.07 300.21 517.91 312.05 234.82 

21-30 193.52 450.56 131.21 168.68 240.94 383.03 368.00 228.75 358.06 288.21 567.57 518.30 750.37 459.05 255.40 418.13 379.21 649.10 343.20 

1-10 386.85 409.27 227.98 259.58 317.10 424.80 317.15 191.50 245.71 230.05 554.39 409.78 836.27 507.51 250.37 516.36 615.05 337.03 437.60 

11-20 337.49 413.86 313.42 338.27 415.06 535.66 263.74 302.60 336.85 272.66 502.97 396.45 807.65 588.34 262.35 689.83 624.18 375.79 385.38 

21-31 228.96 342.09 424.03 334.45 486.40 662.56 434.81 344.56 573.78 533.99 724.26 918.59 712.54 700.12 252.94 941.82 699.63 495.04 385.30 

1987- 

1988 

1988- 

1989 

1989- 

1990 

1990- 

1991 

1991- 

1992 

1992- 

1993 

1993- 

1994 

2000- 

2001 

2001- 

2002 

2002- 

2003 

Table - I 

58

NAYING H.E.PROJECT 

90% dependable 

year 2002-03 flows 

(CUMECS) 

Table - II 

90% DEPENDABLE AND 50% DEPENDABLE YEAR FLOWS FOR POWER 

GENERATION 

JUNE 

JULY 

AUG 

SEP 

OCT 

NOV 

DEC 

JAN 

FEB 

MARCH 

APRIL 

MAY 

MONTH / PERIOD 

50% dependable 

year 1985-86 flows 

(CUMECS) 

1-10 393.57 772.91 

11-20 559.79 783.04 

21-30 669.95 784.32 

1-10 955.48 868.69 

11-20 635.66 1138.68 

21-31 1474.61 1026.62 

1-10 517.25 883.36 

11-20 657.92 962.71 

21-31 416.49 1132.89 

1-10 316.67 922.84 

11-20 404.57 869.97 

21-30 524.72 591.38 

1-10 451.14 466.23 

11-20 284.00 422.19 

21-31 243.77 393.53 

1-10 174.33 389.23 

11-20 163.85 355.82 

21-30 103.39 293.64 

1-10 91.97 265.71 

11-20 78.44 228.71 

21-31 77.11 219.42 

1-10 60.57 193.04 

11-20 54.01 173.53 

21-31 54.50 150.37 

1-10 57.70 118.34 

11-20 62.23 111.61 

21-28 71.77 119.81 

1-10 78.81 114.40 

11-20 150.67 117.90 

21-31 145.76 102.61 

1-10 272.87 111.12 

11-20 234.82 138.50 

21-30 343.20 228.75 

1-10 437.60 191.50 

11-20 385.38 302.60 

21-31 385.30 344.56 

59

Installed 

1000 MW 

Capacity 

FRL 805 

MDDL 765 

Sl. No. Year 

Annual Energy 

100% M/C 

availability 

(MU) 


RESERVOIR OPERATION REPORT 

Annual Energy arranged in Descending order 

Selected Net 

Head 

Design 

Discharge 

Head 

Losses 

Annual 

Energy 

95% M/C 

availability 

(MU) 

245 M 

452.71 

Overall 

Efficiency 

Machine 

Availability 

10% Spill option 

Firm Power 

Annual 

Load 

Factor(%) 

Lean 

Season (Dec 

- Feb) 

Load Factor 

(%) 

92% 

95% 

Minimum 

Reservoir 

level 

Table-IIIA 

With min. spill 

Minimum 

peaking 

hours 

supported 

by the 

reservoir 

operation 

1 1989-90 7860.01 7579.94 598.16 89.22 72.36 765 14.36 

2 1990-91 7607.66 7298.14 89.73 86.11 62.45 765 12.37 

3 1991-92 7113.39 6868.61 420.19 81.2 52.41 765 11.76 

4 1993-94 7065.59 6868.79 458.41 80.66 59.71 765 11 

5 1988-89 7017.42 6820.62 463.92 80.11 57.18 765 11.41 

6 1992-93 6335.63 6189.23 470.72 72.32 50.43 765 11.3 

7 1985-86 6045.47 5892.75 237.29 69.01 40.95 765 5.69 

8 2000-01 6008.38 5812.78 201.09 68.59 26.44 765 4.83 

9 1979-80 5839.14 5670.18 188.83 66.66 24.95 765 4.53 

10 1982-83 5806.66 5647.06 213.86 66.29 28.58 765 5.13 

11 1987-88 5806.51 5634.91 207.45 66.28 30.81 765 4.98 

12 1984-85 5664.7 5515.89 167.1 64.67 22.46 765 4.01 

13 1983-84 5648.42 5538.03 195.64 64.48 22.28 765 4.7 

14 1981-82 5595.88 5449.48 181.84 63.88 27.97 765 4.36 

15 2001-02 5530.16 5383.76 159.53 63.13 18.78 765 3.83 

16 1986-87 5352.07 5198.48 137.17 61.1 19.94 765 3.29 

17 1978-79 5139.68 5018.48 160.85 58.67 23.62 765 3.86 

18 2002-03 5077.15 4966.76 150.16 57.96 16.68 765 3.6 

19 1980-81 5045.89 4886.31 178.32 57.6 19.38 765.00 4.28 

60

Installed 

Capacity 

1000 MW 

FRL 805 

MDDL 765 

Sl. No. Year 

Annual Energy 

100% M/C 

availability 

(MU) 


RESERVOIR OPERATION REPORT 

Selected Net 

Head 

Design 

Discharge 

Head 

Losses 

Annual 

Energy 

95% M/C 

availability 

(MU) 

245 M 

452.71 

Overall 

Efficiency 

Machine 

Availability 

10% Spill option 

Firm Power 

Annual 

Load 

Factor(%) 

Lean 

Season (Dec 

- Feb) 

Load Factor 

(%) 

92% 

95% 

With min. spill 

Minimum 

Reservoir 

level 

Table-IIIB 

Minimum 

peaking 

hours 

supported 

by the 

reservoir 

operation 

1 1978-79 5139.68 5018.48 160.85 58.67 23.62 765 3.86 

2 1979-80 5839.14 5670.18 188.83 66.66 24.95 765 4.53 

3 1980-81 5045.89 4886.31 178.32 57.6 19.38 765 4.28 

4 1981-82 5595.88 5449.48 181.84 63.88 27.97 765 4.36 

5 1982-83 5806.66 5647.06 213.86 66.29 28.58 765 5.13 

6 1983-84 5648.42 5538.03 195.64 64.48 22.28 765 4.7 

7 1984-85 5664.7 5515.89 167.1 64.67 22.46 765 4.01 

8 1985-86 6045.47 5892.75 237.29 69.01 40.95 765 5.69 

9 1986-87 5352.07 5198.48 137.17 61.1 19.94 765 3.29 

10 1987-88 5806.51 5634.91 207.45 66.28 30.81 765 4.98 

11 1988-89 7017.42 6820.62 463.92 80.11 57.18 765 11.41 

12 1989-90 7860.01 7579.94 598.16 89.22 72.36 765 14.36 

13 1990-91 7607.66 7298.14 89.73 86.11 62.45 765 12.37 

14 1991-92 7113.39 6868.61 420.19 81.20 52.41 765 11.76 

15 1992-93 6335.63 6189.23 470.72 72.32 50.43 765 11.3 

16 1993-94 7065.59 6868.79 458.41 80.66 59.71 765 11.0 

17 2000-01 6008.38 5812.78 201.09 68.59 26.44 765 4.83 

18 2001-02 5530.16 5383.76 159.53 63.13 18.78 765 3.83 

19 2002-03 5077.15 4966.76 150.16 57.96 16.68 765.00 3.6 

61

Load 

Factor 

Installed Capacity 

(MW) 

PERIOD 

Jun-02 

Jul-02 

Aug-02 

Sep-02 

Oct-02 

Nov-02 

Dec-02 

Jan-03 

Feb-03 

Mar-03 

Apr-03 

May-03 

57.96 1 0 0 0 YEAR 2002-2003 Static Head 

Starting 

Reservoir 

Level 

1000 FRL (m) . 805 

Design 

Discharge 

(m3/s) 

452.71 

Initial 

Storage 

Inflows into the Reservoir 

Area of 

Reservoir 

Total 

storage 


RESERVOIR OPERATION STUDY 

Head 

Loss 

Turbine 

discharge 

10% 

Net storage 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

storage 

55.00 3 

Rated Head (m). 245.00 Overall Efficiency 92% 765 

Tail water 

Level 

Net Head 

(H) 

Power (P) Energy (E) 

Energy with 95% 

m/c avail. 

m Mcm Mcm m3/s Ha Mcm m3/s Mcm m m3/s m m MW GWH GWH Hrs. 

1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 340.04 393.57 100.00 365.04 387.90 29.90 769.90 0.00 520.00 220.50 771.16 185.08 185.08 21.68 

769.90 29.90 483.66 559.79 109.80 513.55 433.75 80.00 805.00 68.05 520.00 224.91 879.55 211.09 211.09 24.00 

805.00 80.00 578.83 669.95 185.00 658.83 432.41 80.00 805.00 237.54 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 825.53 955.48 185.00 905.53 432.41 80.00 805.00 523.07 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 549.21 635.66 185.00 629.21 432.41 80.00 805.00 203.25 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1401.46 1474.61 185.00 1481.46 432.41 80.00 805.00 1042.19 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 446.91 517.25 185.00 526.91 432.41 80.00 805.00 84.84 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 568.44 657.92 185.00 648.44 432.41 80.00 805.00 225.50 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 395.83 416.49 185.00 475.83 432.41 64.87 796.52 0.00 520.00 256.50 1000.00 264.00 250.80 24.00 

796.52 64.87 273.60 316.67 166.31 338.47 362.81 25.00 765.00 0.00 520.00 248.87 814.09 195.38 195.38 19.54 

765.00 25.00 349.55 404.57 100.00 374.55 342.71 78.45 804.17 0.00 520.00 220.50 681.31 163.51 163.51 19.15 

804.17 78.45 453.36 524.72 183.34 531.81 433.67 80.00 805.00 89.25 520.00 255.75 1000.00 240.00 228.00 24.00 

805.00 80.00 389.79 451.14 185.00 469.79 432.41 80.00 805.00 18.73 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 245.38 284.00 185.00 325.38 284.00 80.00 805.00 0.00 520.00 256.50 656.78 157.63 157.63 15.76 

805.00 80.00 231.68 243.77 185.00 311.68 243.77 80.00 805.00 0.00 520.00 256.50 563.74 148.83 148.83 13.53 

805.00 80.00 150.62 174.33 185.00 230.62 174.33 80.00 805.00 0.00 520.00 256.50 403.15 96.76 96.76 9.68 

805.00 80.00 141.57 163.85 185.00 221.57 163.85 80.00 805.00 0.00 520.00 256.50 378.93 90.94 90.94 9.09 

805.00 80.00 89.33 103.39 185.00 169.33 103.39 80.00 805.00 0.00 520.00 256.50 239.10 57.38 57.38 5.74 

805.00 80.00 79.46 91.97 185.00 159.46 91.97 80.00 805.00 0.00 520.00 256.50 212.68 51.04 51.04 5.10 

805.00 80.00 67.77 78.44 185.00 147.77 78.44 80.00 805.00 0.00 520.00 256.50 181.40 43.54 43.54 4.35 

805.00 80.00 73.29 77.11 185.00 153.29 77.11 80.00 805.00 0.00 520.00 256.50 178.32 47.08 47.08 4.28 

805.00 80.00 52.33 60.57 185.00 132.33 65.97 75.33 802.50 0.00 520.00 256.50 152.57 36.62 36.62 3.66 

802.50 75.33 46.67 54.01 180.00 122.00 69.44 62.00 794.80 0.00 520.00 254.25 159.19 38.21 38.21 3.82 

794.80 62.00 51.79 54.50 162.00 113.79 67.34 49.79 786.99 0.00 520.00 247.32 150.16 39.64 39.64 3.60 

786.99 49.79 49.86 57.70 144.59 99.65 69.44 39.65 779.65 0.00 520.00 240.29 150.45 36.11 36.11 3.72 

779.65 39.65 53.77 62.23 131.22 93.41 71.76 31.41 771.41 0.00 520.00 233.68 151.19 36.29 36.29 3.90 

771.41 31.41 49.61 71.77 113.11 81.02 81.05 25.00 765.00 0.00 520.00 226.27 165.34 31.75 31.75 4.47 

765.00 25.00 68.09 78.81 100.00 93.09 78.81 25.00 765.00 0.00 520.00 220.50 156.67 37.60 37.60 4.40 

765.00 25.00 130.18 150.67 100.00 155.19 150.67 25.00 765.00 0.00 520.00 220.50 299.55 71.89 71.89 8.42 

765.00 25.00 138.53 145.76 100.00 163.54 145.76 25.00 765.00 0.00 520.00 220.50 289.78 76.50 76.50 8.15 

765.00 25.00 235.76 272.87 100.00 260.76 272.87 25.00 765.00 0.00 520.00 220.50 542.47 130.19 130.19 15.25 

765.00 25.00 202.88 234.82 100.00 227.88 234.82 25.00 765.00 0.00 520.00 220.50 466.82 112.04 112.04 13.12 

765.00 25.00 296.53 343.20 100.00 321.53 343.20 25.00 765.00 0.00 520.00 220.50 682.30 163.75 163.75 19.18 

765.00 25.00 378.09 437.60 100.00 403.09 413.31 45.99 784.28 0.00 520.00 220.50 821.68 197.20 197.20 23.10 

784.28 45.99 332.97 385.38 139.70 378.96 409.61 25.06 765.06 0.00 520.00 237.85 878.39 210.81 210.81 22.04 

765.06 25.06 366.19 385.30 100.13 391.25 385.37 25.00 765.00 0.00 520.00 220.56 766.32 202.31 202.31 21.53 

Total 

Inflows 

10588.54 9496.41 

Av.Net 

Head 

242.63 150.16 5077.15 4966.76 3.60 

Spill 

Peaking 

Hours 

62


POWER POTENTIAL IN 90% Dependable Year 

Table - V 

Net Head 245.00 Incremental Steps 

2002-2003 

200 Overall Efficiency 

92% 

Period 

Inflow 

(Cumecs) 

Unrestricted 

Power 

Energy 

Potential 

Generation 

(MW) 

(MU) 

600 800 1000 1200 1400 

ENERGY GENERATION IN MU RESTRICTED TO VARIOUS MW 

1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 3600 

1-10 393.57 870.25 208.86 144.00 192.00 208.86 208.86 208.86 208.86 208.86 208.86 208.86 208.86 208.86 208.86 208.86 208.86 208.86 208.86 

Jun-02 11-20 559.79 1237.79 297.07 144.00 192.00 240.00 288.00 297.07 297.07 297.07 297.07 297.07 297.07 297.07 297.07 297.07 297.07 297.07 297.07 

21-30 669.95 1481.37 355.53 144.00 192.00 240.00 288.00 336.00 355.53 355.53 355.53 355.53 355.53 355.53 355.53 355.53 355.53 355.53 355.53 

1-10 955.48 2112.73 507.05 144.00 192.00 240.00 288.00 336.00 384.00 432.00 480.00 507.05 507.05 507.05 507.05 507.05 507.05 507.05 507.05 

Jul-02 11-20 635.66 1405.56 337.34 144.00 192.00 240.00 288.00 336.00 337.34 337.34 337.34 337.34 337.34 337.34 337.34 337.34 337.34 337.34 337.34 

21-31 1474.61 3260.61 860.80 158.40 211.20 264.00 316.80 369.60 422.40 475.20 528.00 580.80 633.60 686.40 739.20 792.00 844.80 860.80 860.80 

1-10 517.25 1143.74 274.50 144.00 192.00 240.00 274.50 274.50 274.50 274.50 274.50 274.50 274.50 274.50 274.50 274.50 274.50 274.50 274.50 

Aug-02 11-20 657.92 1454.77 349.14 144.00 192.00 240.00 288.00 336.00 349.14 349.14 349.14 349.14 349.14 349.14 349.14 349.14 349.14 349.14 349.14 

21-31 416.49 920.93 243.13 158.40 211.20 243.13 243.13 243.13 243.13 243.13 243.13 243.13 243.13 243.13 243.13 243.13 243.13 243.13 243.13 

1-10 316.67 700.20 168.05 144.00 168.05 168.05 168.05 168.05 168.05 168.05 168.05 168.05 168.05 168.05 168.05 168.05 168.05 168.05 168.05 

Sep-02 11-20 404.57 894.57 214.70 144.00 192.00 214.70 214.70 214.70 214.70 214.70 214.70 214.70 214.70 214.70 214.70 214.70 214.70 214.70 214.70 

21-30 524.72 1160.25 278.46 144.00 192.00 240.00 278.46 278.46 278.46 278.46 278.46 278.46 278.46 278.46 278.46 278.46 278.46 278.46 278.46 

1-10 451.14 997.55 239.41 144.00 192.00 239.41 239.41 239.41 239.41 239.41 239.41 239.41 239.41 239.41 239.41 239.41 239.41 239.41 239.41 

Oct-02 11-20 284.00 627.97 150.71 144.00 150.71 150.71 150.71 150.71 150.71 150.71 150.71 150.71 150.71 150.71 150.71 150.71 150.71 150.71 150.71 

21-31 243.77 539.01 142.30 142.30 142.30 142.30 142.30 142.30 142.30 142.30 142.30 142.30 142.30 142.30 142.30 142.30 142.30 142.30 142.30 

1-10 174.33 385.47 92.51 92.51 92.51 92.51 92.51 92.51 92.51 92.51 92.51 92.51 92.51 92.51 92.51 92.51 92.51 92.51 92.51 

Nov-02 11-20 163.85 362.31 86.95 86.95 86.95 86.95 86.95 86.95 86.95 86.95 86.95 86.95 86.95 86.95 86.95 86.95 86.95 86.95 86.95 

21-30 103.39 228.61 54.87 54.87 54.87 54.87 54.87 54.87 54.87 54.87 54.87 54.87 54.87 54.87 54.87 54.87 54.87 54.87 54.87 

1-10 91.97 203.35 48.80 48.80 48.80 48.80 48.80 48.80 48.80 48.80 48.80 48.80 48.80 48.80 48.80 48.80 48.80 48.80 48.80 

Dec-02 11-20 78.44 173.45 41.63 41.63 41.63 41.63 41.63 41.63 41.63 41.63 41.63 41.63 41.63 41.63 41.63 41.63 41.63 41.63 41.63 

21-31 77.11 170.50 45.01 45.01 45.01 45.01 45.01 45.01 45.01 45.01 45.01 45.01 45.01 45.01 45.01 45.01 45.01 45.01 45.01 

1-10 60.57 133.92 32.14 32.14 32.14 32.14 32.14 32.14 32.14 32.14 32.14 32.14 32.14 32.14 32.14 32.14 32.14 32.14 32.14 

Jan-03 11-20 54.01 119.43 28.66 28.66 28.66 28.66 28.66 28.66 28.66 28.66 28.66 28.66 28.66 28.66 28.66 28.66 28.66 28.66 28.66 

21-31 54.50 120.50 31.81 31.81 31.81 31.81 31.81 31.81 31.81 31.81 31.81 31.81 31.81 31.81 31.81 31.81 31.81 31.81 31.81 

1-10 57.70 127.60 30.62 30.62 30.62 30.62 30.62 30.62 30.62 30.62 30.62 30.62 30.62 30.62 30.62 30.62 30.62 30.62 30.62 

Feb-03 11-20 62.23 137.60 33.02 33.02 33.02 33.02 33.02 33.02 33.02 33.02 33.02 33.02 33.02 33.02 33.02 33.02 33.02 33.02 33.02 

21-28 71.77 158.70 30.47 30.47 30.47 30.47 30.47 30.47 30.47 30.47 30.47 30.47 30.47 30.47 30.47 30.47 30.47 30.47 30.47 

1-10 78.81 174.25 41.82 41.82 41.82 41.82 41.82 41.82 41.82 41.82 41.82 41.82 41.82 41.82 41.82 41.82 41.82 41.82 41.82 

Mar-03 11-20 150.67 333.17 79.96 79.96 79.96 79.96 79.96 79.96 79.96 79.96 79.96 79.96 79.96 79.96 79.96 79.96 79.96 79.96 79.96 

21-31 145.76 322.31 85.09 85.09 85.09 85.09 85.09 85.09 85.09 85.09 85.09 85.09 85.09 85.09 85.09 85.09 85.09 85.09 85.09 

1-10 272.87 603.36 144.81 144.00 144.81 144.81 144.81 144.81 144.81 144.81 144.81 144.81 144.81 144.81 144.81 144.81 144.81 144.81 144.81 

Apr-03 11-20 234.82 519.22 124.61 124.61 124.61 124.61 124.61 124.61 124.61 124.61 124.61 124.61 124.61 124.61 124.61 124.61 124.61 124.61 124.61 

21-30 343.20 758.88 182.13 144.00 182.13 182.13 182.13 182.13 182.13 182.13 182.13 182.13 182.13 182.13 182.13 182.13 182.13 182.13 182.13 

1-10 437.60 967.62 232.23 144.00 192.00 232.23 232.23 232.23 232.23 232.23 232.23 232.23 232.23 232.23 232.23 232.23 232.23 232.23 232.23 

May-03 11-20 385.38 852.15 204.52 144.00 192.00 204.52 204.52 204.52 204.52 204.52 204.52 204.52 204.52 204.52 204.52 204.52 204.52 204.52 204.52 

21-31 385.30 851.96 224.92 158.40 211.20 224.92 224.92 224.92 224.92 224.92 224.92 224.92 224.92 224.92 224.92 224.92 224.92 224.92 224.92 

6503.64 3809.49 4613.59 5187.75 5553.51 5807.38 5942.19 6042.99 6143.79 6223.64 6276.44 6329.24 6382.04 6434.84 6487.64 6503.64 6503.64 

63

NAYING H.E. PROJECT 


Load 

58.67 1 

Factor 


1000 

(MW) 

Starting 

Initial 

PERIOD Reservoir 

Storage 

Level 

0 

FRL (m) . 805 

Inflows into the 

Reservoir 

0 0 

Design 

Discharge 452.71 

(m3/s) 

Area of Total 

Reservoir storage 

YEAR 

Head 

10% 

Loss 

Turbine 

Net storage 

discharge 

1978-1979 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

Static Head 

55.00 3 

storage 


Tail water Net Head 

Energy with 95% Peaking 

Spill 


Level (H) 

m/c avail. Hours 


1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 443.71 513.55 100.00 468.71 429.48 80.00 805.00 20.42 520.00 220.50 853.81 204.92 204.92 24.00 

Jun-78 805.00 80.00 640.57 741.40 185.00 720.57 432.41 80.00 805.00 308.99 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 947.35 1096.47 185.00 1027.35 432.41 80.00 805.00 664.06 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 518.87 600.55 185.00 598.87 432.41 80.00 805.00 168.14 520.00 256.50 1000.00 240.00 228.00 24.00 

Jul-78 805.00 80.00 597.94 692.05 185.00 677.94 432.41 80.00 805.00 259.64 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 609.80 641.62 185.00 689.80 432.41 80.00 805.00 209.21 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 538.76 623.56 185.00 618.76 432.41 80.00 805.00 191.15 520.00 256.50 1000.00 240.00 228.00 24.00 

Aug-78 805.00 80.00 385.49 446.17 185.00 465.49 432.41 80.00 805.00 13.76 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 230.07 242.08 185.00 310.07 299.87 25.07 765.07 0.00 520.00 256.50 693.49 183.08 183.08 16.64 

765.07 25.07 487.15 563.83 100.14 512.22 389.94 80.00 805.00 110.32 520.00 220.56 775.44 186.11 186.11 21.79 

Sep-78 805.00 80.00 642.86 744.05 185.00 722.86 432.41 80.00 805.00 311.64 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 505.86 585.49 185.00 585.86 432.41 80.00 805.00 153.08 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 396.66 459.09 185.00 476.66 432.41 80.00 805.00 26.68 520.00 256.50 1000.00 240.00 228.00 24.00 

Oct-78 805.00 80.00 263.41 304.88 185.00 343.41 304.88 80.00 805.00 0.00 520.00 256.50 705.06 169.21 169.21 16.92 

805.00 80.00 240.96 253.54 185.00 320.96 254.26 79.31 804.63 0.00 520.00 256.50 588.01 155.23 155.23 14.11 

804.63 79.31 198.60 229.87 184.26 277.92 229.17 79.92 804.96 0.00 520.00 256.17 529.29 127.03 127.03 12.70 

Nov-78 804.96 79.92 160.86 186.18 184.91 240.77 186.34 79.77 804.88 0.00 520.00 256.46 430.87 103.41 103.41 10.34 

804.88 79.77 195.16 225.88 184.76 274.94 225.69 79.94 804.97 0.00 520.00 256.39 521.72 125.21 125.21 12.52 

804.97 79.94 132.18 152.99 184.93 212.12 153.94 79.12 804.53 0.00 520.00 256.47 355.95 85.43 85.43 8.54 

Dec-78 804.53 79.12 114.72 132.78 184.06 193.84 131.94 79.84 804.92 0.00 520.00 256.08 304.63 73.11 73.11 7.31 

804.92 79.84 110.69 116.46 184.83 190.53 116.79 79.53 804.75 0.00 520.00 256.42 270.02 71.28 71.28 6.48 

804.75 79.53 83.32 96.44 184.50 162.86 96.06 79.86 804.92 0.00 520.00 256.27 221.96 53.27 53.27 5.33 

Jan-79 804.92 79.86 75.66 87.56 184.85 155.51 87.96 79.51 804.74 0.00 520.00 256.43 203.37 48.81 48.81 4.88 

804.74 79.51 82.58 86.89 184.48 162.09 94.70 72.09 800.77 0.00 520.00 256.26 218.80 57.76 57.76 5.25 

800.77 72.09 68.38 79.14 176.53 140.47 70.60 79.47 804.72 0.00 520.00 252.69 160.85 38.60 38.60 3.86 

Feb-79 804.72 79.47 58.07 67.21 184.43 137.53 71.76 75.53 802.61 0.00 520.00 256.24 165.79 39.79 39.79 3.98 

802.61 75.53 70.31 101.72 180.22 145.84 95.49 79.84 804.92 0.00 520.00 254.35 218.97 42.04 42.04 5.26 

804.92 79.84 89.95 104.11 184.83 169.79 104.17 79.79 804.89 0.00 520.00 256.42 240.82 57.80 57.80 5.78 

Mar-79 804.89 79.79 92.47 107.02 184.78 172.26 150.67 42.08 781.48 0.00 520.00 256.40 348.31 83.60 83.60 8.36 

781.48 42.08 140.48 147.81 134.67 182.56 145.76 44.03 782.88 0.00 520.00 235.34 309.28 81.65 81.65 7.88 

782.88 44.03 136.60 158.10 137.18 180.63 178.82 26.13 766.13 0.00 520.00 236.59 381.44 91.54 91.54 9.65 

Apr-79 766.13 26.13 156.57 181.21 102.25 182.69 181.11 26.21 766.21 0.00 520.00 221.51 361.71 86.81 86.81 10.10 

766.21 26.21 167.20 193.52 102.43 193.41 192.74 26.88 766.88 0.00 520.00 221.59 385.07 92.42 92.42 10.74 

766.88 26.88 334.24 386.85 103.77 361.13 386.69 27.03 767.03 0.00 520.00 222.20 774.66 185.92 185.92 21.53 

May-79 767.03 27.03 291.59 337.49 104.05 318.62 337.96 26.62 766.62 0.00 520.00 222.32 677.44 162.59 162.59 18.81 

766.62 26.62 217.61 228.96 103.24 244.22 206.44 25.00 765.00 24.23 520.00 221.96 413.12 109.06 109.06 11.50 

Total Inflows 

10426.70 9447.36 

Av.Net 

Head 

248.34 160.85 5139.68 5018.48 3.86 

64



Load 

66.66 1 

Factor 


1000 

(MW) 

Starting 

Initial 


Storage 

Level 

0 

FRL (m) . 805 


Reservoir 

0 0 

Design 


(m3/s) 



YEAR 

Head 

10% 

Loss 

Turbine 

Net storage 

discharge 

1979-1980 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

Static Head 

55.00 3 

storage 




Spill 


Level (H) 



1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 613.03 709.53 100.00 638.03 429.48 80.00 805.00 216.39 520.00 220.50 853.81 204.92 204.92 24.00 

Jun-79 805.00 80.00 834.52 965.89 185.00 914.52 432.41 80.00 805.00 533.47 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 925.16 1070.79 185.00 1005.16 432.41 80.00 805.00 638.38 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1401.00 1621.53 185.00 1481.00 432.41 80.00 805.00 1189.12 520.00 256.50 1000.00 240.00 228.00 24.00 

Jul-79 805.00 80.00 1009.40 1168.28 185.00 1089.40 432.41 80.00 805.00 735.87 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 998.73 1050.86 185.00 1078.73 432.41 80.00 805.00 618.44 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 501.78 580.76 185.00 581.78 432.41 80.00 805.00 148.35 520.00 256.50 1000.00 240.00 228.00 24.00 

Aug-79 805.00 80.00 365.96 423.57 185.00 445.96 432.41 72.36 800.91 0.00 520.00 256.50 1000.00 240.00 228.00 24.00 

800.91 72.36 783.88 824.79 176.82 856.24 438.70 80.00 805.00 378.04 520.00 252.82 999.99 264.00 250.80 24.00 

805.00 80.00 783.58 906.92 185.00 863.58 432.41 80.00 805.00 474.51 520.00 256.50 1000.00 240.00 228.00 24.00 

Sep-79 805.00 80.00 774.22 896.09 185.00 854.22 432.41 80.00 805.00 463.68 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 347.75 402.48 185.00 427.75 432.41 54.14 790.08 0.00 520.00 256.50 1000.00 240.00 228.00 24.00 

790.08 54.14 724.82 838.91 150.21 778.96 450.93 80.00 805.00 358.06 520.00 243.08 988.25 237.18 228.00 24.00 

Oct-79 805.00 80.00 439.47 508.65 185.00 519.47 432.41 80.00 805.00 76.24 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 165.46 174.10 185.00 245.46 231.48 25.46 765.46 0.00 520.00 256.50 535.33 141.33 141.33 12.85 

765.46 25.46 165.70 191.78 100.93 191.16 174.33 40.55 780.39 0.00 520.00 220.92 347.22 83.33 83.33 9.73 

Nov-79 780.39 40.55 127.72 147.83 132.70 168.27 163.85 26.70 766.70 0.00 520.00 234.35 346.21 83.09 83.09 8.88 

766.70 26.70 109.82 127.10 103.40 136.52 103.39 47.19 785.14 0.00 520.00 222.03 206.97 49.67 49.67 5.76 

785.14 47.19 120.27 139.21 141.24 167.46 91.97 80.00 805.00 9.27 520.00 238.62 197.86 47.49 47.49 4.94 

Dec-79 805.00 80.00 103.17 119.41 185.00 183.17 115.74 80.00 805.00 3.67 520.00 256.50 267.66 64.24 64.24 6.42 

805.00 80.00 112.07 117.92 185.00 192.07 117.63 80.00 805.00 0.29 520.00 256.50 272.04 71.82 71.82 6.53 

805.00 80.00 100.42 116.23 185.00 180.42 128.47 69.42 799.26 0.00 520.00 256.50 297.11 71.31 71.31 7.13 

Jan-80 799.26 69.42 81.70 94.56 173.14 151.12 83.33 79.12 804.53 0.00 520.00 251.33 188.83 45.32 45.32 4.53 

804.53 79.12 95.72 100.72 184.06 174.84 99.96 79.84 804.92 0.00 520.00 256.08 230.78 60.93 60.93 5.54 

804.92 79.84 106.39 123.13 184.83 186.23 122.69 80.00 805.00 0.27 520.00 256.42 283.64 68.07 68.07 6.81 

Feb-80 805.00 80.00 93.82 108.59 185.00 173.82 109.95 78.82 804.37 0.00 520.00 256.50 254.28 61.03 61.03 6.10 

804.37 78.82 76.73 111.01 183.74 155.56 109.95 79.56 804.76 0.00 520.00 255.93 253.72 48.71 48.71 6.09 

804.76 79.56 214.10 247.80 184.52 293.65 247.69 79.65 804.81 0.00 520.00 256.29 572.32 137.36 137.36 13.74 

Mar-80 804.81 79.65 165.52 191.58 184.63 245.18 192.13 79.18 804.56 0.00 520.00 256.33 444.03 106.57 106.57 10.66 

804.56 79.18 184.58 194.22 184.12 263.76 194.65 78.76 804.34 0.00 520.00 256.10 449.46 118.66 118.66 10.79 

804.34 78.76 183.24 212.08 183.67 262.00 272.87 26.24 766.24 0.00 520.00 255.90 629.56 151.09 151.09 15.11 

Apr-80 766.24 26.24 267.10 309.15 102.48 293.35 247.69 79.35 804.65 0.00 520.00 221.62 494.90 118.78 118.78 13.81 

804.65 79.35 389.29 450.56 184.30 468.63 432.94 80.00 805.00 16.87 520.00 256.19 999.99 240.00 228.00 24.00 

805.00 80.00 353.61 409.27 185.00 433.61 413.31 76.51 803.13 0.00 520.00 256.50 955.82 229.40 228.00 22.94 

May-80 803.13 76.51 357.57 413.86 181.26 434.08 410.88 79.08 804.51 0.00 520.00 254.82 943.97 226.55 226.55 22.66 

804.51 79.08 325.13 342.09 184.01 404.21 400.88 23.21 763.80 0.00 520.00 256.06 925.48 244.33 244.33 22.21 

Total 

Inflows 

14402.46 ####### 

Av.Net 

Head 

250.72 188.83 5839.14 5670.18 4.53 

65



Load 

57.60 1 

Factor 


1000 

(MW) 

Starting 

Initial 


Storage 

Level 

0 

FRL (m) . 805 


Reservoir 

0 0 

Design 


(m3/s) 



YEAR 

Head 

10% 

Loss 

Turbine 

Net storage 

discharge 

1980-1981 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

Static Head 

55.00 3 

storage 




Spill 


Level (H) 



1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 525.07 607.72 100.00 550.07 429.48 80.00 805.00 114.58 520.00 220.50 853.81 204.92 204.92 24.00 

Jun-80 805.00 80.00 763.76 883.98 185.00 843.76 432.41 80.00 805.00 451.57 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 575.98 666.64 185.00 655.98 432.41 80.00 805.00 234.23 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 606.17 701.59 185.00 686.17 432.41 80.00 805.00 269.17 520.00 256.50 1000.00 240.00 228.00 24.00 

Jul-80 805.00 80.00 627.64 726.43 185.00 707.64 432.41 80.00 805.00 294.02 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 611.49 643.40 185.00 691.49 432.41 80.00 805.00 210.99 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 1128.12 1305.70 185.00 1208.12 432.41 80.00 805.00 873.29 520.00 256.50 1000.00 240.00 228.00 24.00 

Aug-80 805.00 80.00 1573.57 1821.27 185.00 1653.57 432.41 80.00 805.00 1388.85 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 603.81 635.32 185.00 683.81 432.41 80.00 805.00 202.91 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 387.33 448.30 185.00 467.33 432.41 80.00 805.00 15.88 520.00 256.50 1000.00 240.00 228.00 24.00 

Sep-80 805.00 80.00 416.22 481.73 185.00 496.22 432.41 80.00 805.00 49.32 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 451.21 522.24 185.00 531.21 432.41 80.00 805.00 89.83 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 392.72 454.53 185.00 472.72 432.41 80.00 805.00 22.12 520.00 256.50 1000.00 240.00 228.00 24.00 

Oct-80 805.00 80.00 275.45 318.81 185.00 355.45 318.87 79.95 804.97 0.00 520.00 256.50 737.41 176.98 176.98 17.70 

804.97 79.95 296.15 311.61 184.95 376.10 369.32 25.10 765.10 0.00 520.00 256.48 854.01 225.46 225.46 20.50 

765.10 25.10 162.80 188.42 100.20 187.90 174.33 37.28 777.28 0.00 520.00 220.59 346.71 83.21 83.21 9.74 

Nov-80 777.28 37.28 126.14 145.99 126.02 163.42 159.72 25.42 765.42 0.00 520.00 231.55 333.45 80.03 80.03 8.71 

765.42 25.42 104.28 120.69 100.83 129.69 103.39 40.37 780.26 0.00 520.00 220.88 205.89 49.41 49.41 5.77 

780.26 40.37 113.34 131.19 132.47 153.71 91.97 74.25 801.92 0.00 520.00 234.24 194.22 46.61 46.61 4.99 

Dec-80 801.92 74.25 76.91 89.01 178.85 151.16 78.44 80.00 805.00 3.92 520.00 253.73 179.44 43.07 43.07 4.31 

805.00 80.00 75.82 79.77 185.00 155.82 77.11 80.00 805.00 2.66 520.00 256.50 178.32 47.08 47.08 4.28 

805.00 80.00 85.68 99.16 185.00 165.68 78.70 80.00 805.00 20.46 520.00 256.50 182.01 43.68 43.68 4.37 

Jan-81 805.00 80.00 74.61 86.35 185.00 154.61 86.81 79.61 804.79 0.00 520.00 256.50 200.75 48.18 48.18 4.82 

804.79 79.61 81.00 85.23 184.58 160.61 85.23 79.61 804.79 0.00 520.00 256.31 196.95 52.00 52.00 4.73 

804.79 79.61 71.84 83.15 184.58 151.45 82.18 80.00 805.00 0.52 520.00 256.31 189.90 45.58 45.58 4.56 

Feb-81 805.00 80.00 76.00 87.96 185.00 156.00 87.96 80.00 805.00 0.00 520.00 256.50 203.42 48.82 48.82 4.88 

805.00 80.00 68.44 99.02 185.00 148.44 98.38 80.00 805.00 0.64 520.00 256.50 227.51 43.68 43.68 5.46 

805.00 80.00 101.22 117.15 185.00 181.22 128.47 70.22 799.74 0.00 520.00 256.50 297.11 71.31 71.31 7.13 

Mar-81 799.74 70.22 96.12 111.25 174.34 166.34 138.89 46.34 784.53 0.00 520.00 251.76 315.26 75.66 75.66 7.57 

784.53 46.34 99.98 105.19 140.15 146.31 125.21 27.31 767.31 0.00 520.00 238.07 268.76 70.95 70.95 6.73 

767.31 27.31 103.61 119.92 104.63 130.92 121.53 25.92 765.92 0.00 520.00 222.58 243.88 58.53 58.53 6.76 

Apr-81 765.92 25.92 103.56 119.86 101.84 129.48 115.74 29.48 769.48 0.00 520.00 221.33 230.96 55.43 55.43 6.46 

769.48 29.48 113.36 131.21 108.97 142.85 135.42 25.85 765.85 0.00 520.00 224.54 274.14 65.79 65.79 7.50 

765.85 25.85 196.97 227.98 101.69 222.82 225.69 27.82 767.82 0.00 520.00 221.26 450.24 108.06 108.06 12.59 

May-81 767.82 27.82 270.80 313.42 105.63 298.61 226.85 80.00 805.00 26.17 520.00 223.03 456.17 109.48 109.48 12.60 

805.00 80.00 403.00 424.03 185.00 483.00 432.40 25.00 765.00 49.51 520.00 256.50 999.96 263.99 250.80 24.00 

Total 

Inflows 

11840.14 9161.01 

Av.Net 

Head 

246.75 178.32 5045.89 4886.31 4.28 

66



Load 

63.88 1 

Factor 


1000 

(MW) 

Starting 

Initial 


Storage 

Level 

0 

FRL (m) . 805 


Reservoir 

0 0 

Design 


(m3/s) 



YEAR 

Head 

10% 

Loss 

Turbine 

Net storage 

discharge 

1981-82 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

Static Head 

55.00 3 

storage 




Spill 


Level (H) 



1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 354.01 409.73 100.00 379.01 408.57 26.00 766.00 0.00 520.00 220.50 812.25 194.94 194.94 22.83 

Jun-81 766.00 26.00 457.75 529.80 102.00 483.75 430.35 80.00 805.00 36.94 520.00 221.40 859.05 206.17 206.17 24.00 

805.00 80.00 676.65 783.16 185.00 756.65 432.41 80.00 805.00 350.74 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 849.49 983.20 185.00 929.49 432.41 80.00 805.00 550.79 520.00 256.50 1000.00 240.00 228.00 24.00 

Jul-81 805.00 80.00 881.02 1019.70 185.00 961.02 432.41 80.00 805.00 587.29 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 650.61 684.56 185.00 730.61 432.41 80.00 805.00 252.15 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 707.08 818.38 185.00 787.08 432.41 80.00 805.00 385.97 520.00 256.50 1000.00 240.00 228.00 24.00 

Aug-81 805.00 80.00 758.92 878.38 185.00 838.92 432.41 80.00 805.00 445.96 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 848.62 892.91 185.00 928.62 432.41 80.00 805.00 460.50 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 689.55 798.09 185.00 769.55 432.41 80.00 805.00 365.67 520.00 256.50 1000.00 240.00 228.00 24.00 

Sep-81 805.00 80.00 695.22 804.66 185.00 775.22 432.41 80.00 805.00 372.24 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 549.96 636.53 185.00 629.96 432.41 80.00 805.00 204.12 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 528.77 612.01 185.00 608.77 432.41 80.00 805.00 179.59 520.00 256.50 1000.00 240.00 228.00 24.00 

Oct-81 805.00 80.00 414.58 479.83 185.00 494.58 432.41 80.00 805.00 47.42 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 389.53 409.86 185.00 469.53 409.86 80.00 805.00 0.00 520.00 256.50 947.85 250.23 250.23 22.75 

805.00 80.00 218.64 253.06 185.00 298.64 253.06 80.00 805.00 0.00 520.00 256.50 585.22 140.45 140.45 14.05 

Nov-81 805.00 80.00 165.71 191.79 185.00 245.71 191.79 80.00 805.00 0.00 520.00 256.50 443.54 106.45 106.45 10.64 

805.00 80.00 152.92 176.99 185.00 232.92 176.99 80.00 805.00 0.00 520.00 256.50 409.31 98.24 98.24 9.82 

805.00 80.00 136.01 157.41 185.00 216.01 157.41 80.00 805.00 0.00 520.00 256.50 364.03 87.37 87.37 8.74 

Dec-81 805.00 80.00 149.05 172.51 185.00 229.05 172.51 80.00 805.00 0.00 520.00 256.50 398.94 95.75 95.75 9.57 

805.00 80.00 148.98 156.76 185.00 228.98 156.76 80.00 805.00 0.00 520.00 256.50 362.52 95.70 95.70 8.70 

805.00 80.00 120.66 139.65 185.00 200.66 139.65 80.00 805.00 0.00 520.00 256.50 322.95 77.51 77.51 7.75 

Jan-82 805.00 80.00 104.58 121.04 185.00 184.58 121.04 80.00 805.00 0.00 520.00 256.50 279.91 67.18 67.18 6.72 

805.00 80.00 82.94 87.27 185.00 162.94 87.27 80.00 805.00 0.00 520.00 256.50 201.81 53.28 53.28 4.84 

805.00 80.00 67.94 78.63 185.00 147.94 78.63 80.00 805.00 0.00 520.00 256.50 181.84 43.64 43.64 4.36 

Feb-82 805.00 80.00 68.44 79.22 185.00 148.44 79.22 80.00 805.00 0.00 520.00 256.50 183.19 43.97 43.97 4.40 

805.00 80.00 61.77 89.36 185.00 141.77 89.36 80.00 805.00 0.00 520.00 256.50 206.66 39.68 39.68 4.96 

805.00 80.00 96.05 111.17 185.00 176.05 111.17 80.00 805.00 0.00 520.00 256.50 257.09 61.70 61.70 6.17 

Mar-82 805.00 80.00 103.13 119.36 185.00 183.13 119.36 80.00 805.00 0.00 520.00 256.50 276.03 66.25 66.25 6.62 

805.00 80.00 122.15 128.53 185.00 202.15 128.53 80.00 805.00 0.00 520.00 256.50 297.23 78.47 78.47 7.13 

805.00 80.00 150.56 174.26 185.00 230.56 174.26 80.00 805.00 0.00 520.00 256.50 403.01 96.72 96.72 9.67 

Apr-82 805.00 80.00 154.47 178.78 185.00 234.47 178.78 80.00 805.00 0.00 520.00 256.50 413.45 99.23 99.23 9.92 

805.00 80.00 145.74 168.68 185.00 225.74 168.68 80.00 805.00 0.00 520.00 256.50 390.08 93.62 93.62 9.36 

805.00 80.00 224.27 259.58 185.00 304.27 259.58 80.00 805.00 0.00 520.00 256.50 600.30 144.07 144.07 14.41 

May-82 805.00 80.00 292.27 338.27 185.00 372.27 338.27 80.00 805.00 0.00 520.00 256.50 782.28 187.75 187.75 18.77 

805.00 80.00 317.86 334.45 185.00 397.86 392.32 25.00 765.00 0.00 520.00 256.50 907.28 239.52 239.52 21.77 

Total 

Inflows 

12535.87 ####### 

Av.Net 

Head 

254.53 181.84 5595.88 5449.48 4.36 

67



Load 

66.29 1 

Factor 


1000 

(MW) 

Starting 

Initial 


Storage 

Level 

0 

FRL (m) . 805 


Reservoir 

0 0 

Design 


(m3/s) 



YEAR 

Head 

10% 

Loss 

Turbine 

Net storage 

discharge 

1982-1983 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

Static Head 

55.00 

storage 

Rated Head (m). 245.00 Overall Efficiency 92% 


Energy with 

Spill 


Level (H) 

95% m/c avail. 

3 

765 

Peaking 

Hours 


1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 385.99 446.75 100.00 410.99 429.48 39.92 779.92 0.00 520.00 220.50 853.81 204.92 204.92 24.00 

Jun-82 779.92 39.92 499.80 578.47 131.83 539.72 442.37 80.00 805.00 89.72 520.00 233.93 933.01 223.92 223.92 24.00 

805.00 80.00 558.94 646.93 185.00 638.94 432.41 80.00 805.00 214.51 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 486.29 562.83 185.00 566.29 432.41 80.00 805.00 130.42 520.00 256.50 1000.00 240.00 228.00 24.00 

Jul-82 805.00 80.00 618.99 716.42 185.00 698.99 432.41 80.00 805.00 284.01 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1087.22 1143.96 185.00 1167.22 432.41 80.00 805.00 711.55 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 661.57 765.71 185.00 741.57 432.41 80.00 805.00 333.30 520.00 256.50 1000.00 240.00 228.00 24.00 

Aug-82 805.00 80.00 481.61 557.42 185.00 561.61 432.41 80.00 805.00 125.01 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 693.71 729.91 185.00 773.71 432.41 80.00 805.00 297.50 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 554.14 641.37 185.00 634.14 432.41 80.00 805.00 208.95 520.00 256.50 1000.00 240.00 228.00 24.00 

Sep-82 805.00 80.00 756.37 875.43 185.00 836.37 432.41 80.00 805.00 443.02 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 643.90 745.25 185.00 723.90 432.41 80.00 805.00 312.84 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 530.19 613.64 185.00 610.19 432.41 80.00 805.00 181.23 520.00 256.50 1000.00 240.00 228.00 24.00 

Oct-82 805.00 80.00 409.73 474.23 185.00 489.73 432.41 80.00 805.00 41.81 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 440.05 463.02 185.00 520.05 432.41 80.00 805.00 30.61 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 236.74 274.00 185.00 316.74 274.00 80.00 805.00 0.00 520.00 256.50 633.66 152.08 152.08 15.21 

Nov-82 805.00 80.00 139.04 160.93 185.00 219.04 160.93 80.00 805.00 0.00 520.00 256.50 372.17 89.32 89.32 8.93 

805.00 80.00 114.66 132.71 185.00 194.66 132.71 80.00 805.00 0.00 520.00 256.50 306.90 73.66 73.66 7.37 

805.00 80.00 197.35 228.42 185.00 277.35 228.42 80.00 805.00 0.00 520.00 256.50 528.24 126.78 126.78 12.68 

Dec-82 805.00 80.00 126.27 146.15 185.00 206.27 146.15 80.00 805.00 0.00 520.00 256.50 337.99 81.12 81.12 8.11 

805.00 80.00 118.56 124.74 185.00 198.56 124.74 80.00 805.00 0.00 520.00 256.50 288.48 76.16 76.16 6.92 

805.00 80.00 90.49 104.73 185.00 170.49 104.73 80.00 805.00 0.00 520.00 256.50 242.20 58.13 58.13 5.81 

Jan-83 805.00 80.00 85.88 99.40 185.00 165.88 99.40 80.00 805.00 0.00 520.00 256.50 229.87 55.17 55.17 5.52 

805.00 80.00 89.14 93.79 185.00 169.14 93.79 80.00 805.00 0.00 520.00 256.50 216.90 57.26 57.26 5.21 

805.00 80.00 83.43 96.57 185.00 163.43 96.57 80.00 805.00 0.00 520.00 256.50 223.32 53.60 53.60 5.36 

Feb-83 805.00 80.00 79.90 92.47 185.00 159.90 92.47 80.00 805.00 0.00 520.00 256.50 213.86 51.33 51.33 5.13 

805.00 80.00 89.81 129.93 185.00 169.81 129.93 80.00 805.00 0.00 520.00 256.50 300.48 57.69 57.69 7.21 

805.00 80.00 97.45 112.79 185.00 177.45 112.79 80.00 805.00 0.00 520.00 256.50 260.84 62.60 62.60 6.26 

Mar-83 805.00 80.00 132.78 153.68 185.00 212.78 153.68 80.00 805.00 0.00 520.00 256.50 355.40 85.30 85.30 8.53 

805.00 80.00 182.97 192.52 185.00 262.97 192.52 80.00 805.00 0.00 520.00 256.50 445.23 117.54 117.54 10.69 

805.00 80.00 157.62 182.43 185.00 237.62 182.43 80.00 805.00 0.00 520.00 256.50 421.90 101.26 101.26 10.13 

Apr-83 805.00 80.00 251.31 290.87 185.00 331.31 353.37 26.00 766.00 0.00 520.00 256.50 817.20 196.13 196.13 19.61 

766.00 26.00 208.17 240.94 102.00 234.17 242.10 25.00 765.00 0.00 520.00 221.40 483.26 115.98 115.98 13.50 

765.00 25.00 273.97 317.10 100.00 298.97 317.10 25.00 765.00 0.00 520.00 220.50 630.40 151.30 151.30 17.72 

May-83 765.00 25.00 358.62 415.06 100.00 383.62 415.06 25.00 765.00 0.00 520.00 220.50 825.16 198.04 198.04 23.19 

765.00 25.00 462.27 486.40 100.00 487.27 429.48 25.00 765.00 56.92 520.00 220.50 853.81 225.41 225.41 24.00 

Total 

Inflows 

12384.93 ####### 

Av.Net 

Head 

250.90 213.86 5806.66 5647.06 5.13 

68



Load 

64.48 1 

Factor 


1000 

(MW) 

Starting 

Initial 


Storage 

Level 

0 

FRL (m) . 805 


Reservoir 

0 0 

Design 


(m3/s) 



YEAR 

Head 

10% 

Loss 

Turbine 

Net storage 

discharge 

1983-1984 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

Static Head 

55.00 3 

storage 




Spill 


Level (H) 



1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 435.57 504.13 100.00 460.57 429.48 80.00 805.00 11.00 520.00 220.50 853.81 204.92 204.92 24.00 

Jun-83 805.00 80.00 321.60 372.23 185.00 401.60 432.41 28.00 768.00 0.00 520.00 256.50 1000.00 240.00 228.00 24.00 

768.00 28.00 398.27 460.96 106.00 426.27 432.10 52.94 789.24 0.00 520.00 223.20 869.54 208.69 208.69 24.00 

789.24 52.94 390.22 451.65 148.63 443.16 432.41 69.55 799.34 0.00 520.00 242.32 944.70 226.73 226.73 23.05 

Jul-83 799.34 69.55 338.42 391.69 173.34 407.97 441.17 26.80 766.80 0.00 520.00 251.40 999.97 239.99 228.00 24.00 

766.80 26.80 628.09 660.87 103.60 654.89 431.05 80.00 805.00 173.84 520.00 222.12 863.24 227.89 227.89 24.00 

805.00 80.00 424.67 491.51 185.00 504.67 432.41 80.00 805.00 59.10 520.00 256.50 1000.00 240.00 228.00 24.00 

Aug-83 805.00 80.00 432.17 500.20 185.00 512.17 432.41 80.00 805.00 67.79 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 494.88 520.70 185.00 574.88 432.41 80.00 805.00 88.29 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 543.93 629.54 185.00 623.93 432.41 80.00 805.00 197.13 520.00 256.50 1000.00 240.00 228.00 24.00 

Sep-83 805.00 80.00 668.42 773.63 185.00 748.42 432.41 80.00 805.00 341.22 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 694.36 803.66 185.00 774.36 432.41 80.00 805.00 371.25 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 309.44 358.14 185.00 389.44 393.38 49.55 786.82 0.00 520.00 256.50 909.74 218.34 218.34 21.83 

Oct-83 786.82 49.55 404.05 467.65 144.28 453.60 432.41 80.00 805.00 0.00 520.00 240.14 936.22 224.69 224.69 23.15 

805.00 80.00 295.72 311.16 185.00 375.72 311.16 80.00 805.00 0.00 520.00 256.50 719.58 189.97 189.97 17.27 

805.00 80.00 162.79 188.41 185.00 242.79 188.41 80.00 805.00 0.00 520.00 256.50 435.72 104.57 104.57 10.46 

Nov-83 805.00 80.00 145.54 168.45 185.00 225.54 168.45 80.00 805.00 0.00 520.00 256.50 389.55 93.49 93.49 9.35 

805.00 80.00 114.62 132.66 185.00 194.62 132.66 80.00 805.00 0.00 520.00 256.50 306.80 73.63 73.63 7.36 

805.00 80.00 93.68 108.43 185.00 173.68 108.43 80.00 805.00 0.00 520.00 256.50 250.76 60.18 60.18 6.02 

Dec-83 805.00 80.00 83.62 96.78 185.00 163.62 96.78 80.00 805.00 0.00 520.00 256.50 223.82 53.72 53.72 5.37 

805.00 80.00 107.21 112.80 185.00 187.21 112.80 80.00 805.00 0.00 520.00 256.50 260.86 68.87 68.87 6.26 

805.00 80.00 84.65 97.98 185.00 164.65 97.98 80.00 805.00 0.00 520.00 256.50 226.58 54.38 54.38 5.44 

Jan-84 805.00 80.00 84.51 97.81 185.00 164.51 97.81 80.00 805.00 0.00 520.00 256.50 226.20 54.29 54.29 5.43 

805.00 80.00 80.40 84.60 185.00 160.40 84.60 80.00 805.00 0.00 520.00 256.50 195.64 51.65 51.65 4.70 

805.00 80.00 79.91 92.49 185.00 159.91 92.49 80.00 805.00 0.00 520.00 256.50 213.90 51.34 51.34 5.13 

Feb-84 805.00 80.00 75.70 87.62 185.00 155.70 87.62 80.00 805.00 0.00 520.00 256.50 202.62 48.63 48.63 4.86 

805.00 80.00 59.55 86.16 185.00 139.55 86.16 80.00 805.00 0.00 520.00 256.50 199.25 38.26 38.26 4.78 

805.00 80.00 75.92 87.87 185.00 155.92 96.17 72.83 801.16 0.00 520.00 256.50 222.41 53.38 53.38 5.34 

Mar-84 801.16 72.83 75.44 87.32 177.32 148.27 87.32 72.83 801.16 0.00 520.00 253.04 199.21 47.81 47.81 4.78 

801.16 72.83 108.63 114.30 177.32 181.45 114.30 72.83 801.16 0.00 520.00 253.04 260.76 68.84 68.84 6.26 

801.16 72.83 274.87 318.14 177.32 347.70 372.00 26.29 766.29 0.00 520.00 253.04 848.70 203.69 203.69 20.37 

Apr-84 766.29 26.29 380.78 440.72 102.58 407.07 430.61 35.02 775.02 0.00 520.00 221.66 860.58 206.54 206.54 24.00 

775.02 35.02 330.94 383.03 121.05 365.96 392.83 26.56 766.56 0.00 520.00 229.52 812.90 195.10 195.10 21.52 

766.56 26.56 367.03 424.80 103.12 393.58 424.80 26.56 766.56 0.00 520.00 221.90 849.88 203.97 203.97 23.66 

May-84 766.56 26.56 462.81 535.66 103.12 489.37 430.84 80.00 805.00 42.96 520.00 221.90 861.97 206.87 206.87 24.00 

805.00 80.00 629.69 662.56 185.00 709.69 432.41 25.00 765.00 288.01 520.00 256.50 1000.00 264.00 250.80 24.00 

Total 

Inflows 

10658.09 ####### 

Av.Net 

Head 

248.70 195.64 5648.42 5538.03 4.70 

69



Load 

64.67 1 

Factor 


1000 

(MW) 

Starting 

Initial 


Storage 

Level 

0 

FRL (m) . 805 


Reservoir 

0 0 

Design 


(m3/s) 



YEAR 

Head 

10% 

Loss 

Turbine 

Net storage 

discharge 

1984-1985 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

Static Head 

55.00 3 

storage 




Spill 


Level (H) 



1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 487.40 564.13 100.00 512.40 429.48 80.00 805.00 70.99 520.00 220.50 853.81 204.92 204.92 24.00 

Jun-84 805.00 80.00 840.34 972.62 185.00 920.34 432.41 80.00 805.00 540.21 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 662.02 766.23 185.00 742.02 432.41 80.00 805.00 333.82 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 792.30 917.01 185.00 872.30 432.41 80.00 805.00 484.60 520.00 256.50 1000.00 240.00 228.00 24.00 

Jul-84 805.00 80.00 967.27 1119.53 185.00 1047.27 432.41 80.00 805.00 687.11 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 933.08 981.78 185.00 1013.08 432.41 80.00 805.00 549.37 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 644.20 745.60 185.00 724.20 432.41 80.00 805.00 313.19 520.00 256.50 1000.00 240.00 228.00 24.00 

Aug-84 805.00 80.00 365.24 422.74 185.00 445.24 432.41 71.64 800.52 0.00 520.00 256.50 1000.00 240.00 228.00 24.00 

800.52 71.64 492.64 518.35 176.05 564.28 439.30 80.00 805.00 70.25 520.00 252.47 999.97 263.99 250.80 24.00 

805.00 80.00 480.14 555.72 185.00 560.14 432.41 80.00 805.00 123.31 520.00 256.50 1000.00 240.00 228.00 24.00 

Sep-84 805.00 80.00 599.72 694.12 185.00 679.72 432.41 80.00 805.00 261.70 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 362.85 419.97 185.00 442.85 432.41 69.25 799.15 0.00 520.00 256.50 1000.00 240.00 228.00 24.00 

799.15 69.25 339.69 393.16 172.88 408.94 439.68 29.05 769.05 0.00 520.00 251.24 995.95 239.03 228.00 23.90 

Oct-84 769.05 29.05 388.14 449.24 108.10 417.19 432.41 43.59 782.56 0.00 520.00 224.15 873.86 209.73 209.73 23.97 

782.56 43.59 429.34 451.74 136.61 472.93 432.41 61.96 794.78 0.00 520.00 236.31 921.28 243.22 243.22 23.34 

794.78 61.96 391.64 453.29 161.95 453.60 432.41 80.00 805.00 0.00 520.00 247.30 964.14 231.39 228.00 23.14 

Nov-84 805.00 80.00 247.70 286.70 185.00 327.70 286.70 80.00 805.00 0.00 520.00 256.50 663.01 159.12 159.12 15.91 

805.00 80.00 212.44 245.88 185.00 292.44 245.88 80.00 805.00 0.00 520.00 256.50 568.63 136.47 136.47 13.65 

805.00 80.00 161.27 186.65 185.00 241.27 186.65 80.00 805.00 0.00 520.00 256.50 431.66 103.60 103.60 10.36 

Dec-84 805.00 80.00 111.01 128.49 185.00 191.01 128.49 80.00 805.00 0.00 520.00 256.50 297.14 71.31 71.31 7.13 

805.00 80.00 92.76 97.60 185.00 172.76 97.60 80.00 805.00 0.00 520.00 256.50 225.71 59.59 59.59 5.42 

805.00 80.00 69.50 80.45 185.00 149.50 80.45 80.00 805.00 0.00 520.00 256.50 186.04 44.65 44.65 4.46 

Jan-85 805.00 80.00 65.55 75.86 185.00 145.55 75.86 80.00 805.00 0.00 520.00 256.50 175.44 42.11 42.11 4.21 

805.00 80.00 68.67 72.26 185.00 148.67 72.26 80.00 805.00 0.00 520.00 256.50 167.10 44.12 44.12 4.01 

805.00 80.00 69.76 80.74 185.00 149.76 80.74 80.00 805.00 0.00 520.00 256.50 186.72 44.81 44.81 4.48 

Feb-85 805.00 80.00 63.17 73.11 185.00 143.17 73.11 80.00 805.00 0.00 520.00 256.50 169.07 40.58 40.58 4.06 

805.00 80.00 53.35 77.18 185.00 133.35 77.18 80.00 805.00 0.00 520.00 256.50 178.49 34.27 34.27 4.28 

805.00 80.00 77.44 89.62 185.00 157.44 89.62 80.00 805.00 0.00 520.00 256.50 207.27 49.74 49.74 4.97 

Mar-85 805.00 80.00 106.60 123.38 185.00 186.60 123.38 80.00 805.00 0.00 520.00 256.50 285.33 68.48 68.48 6.85 

805.00 80.00 111.86 117.70 185.00 191.86 117.70 80.00 805.00 0.00 520.00 256.50 272.19 71.86 71.86 6.53 

805.00 80.00 110.40 127.77 185.00 190.40 127.77 80.00 805.00 0.00 520.00 256.50 295.49 70.92 70.92 7.09 

Apr-85 805.00 80.00 144.30 167.01 185.00 224.30 229.51 26.00 766.00 0.00 520.00 256.50 530.77 127.38 127.38 12.74 

766.00 26.00 317.95 368.00 102.00 343.95 369.16 25.00 765.00 0.00 520.00 221.40 736.89 176.85 176.85 20.59 

765.00 25.00 274.02 317.15 100.00 299.02 317.15 25.00 765.00 0.00 520.00 220.50 630.51 151.32 151.32 17.72 

May-85 765.00 25.00 227.87 263.74 100.00 252.87 263.74 25.00 765.00 0.00 520.00 220.50 524.33 125.84 125.84 14.74 

765.00 25.00 

Total 

Inflows 

413.24 

12174.90 

434.81 100.00 438.24 429.48 

####### 

25.00 765.00 5.33 520.00 

Av.Net 

Head 

220.50 

249.55 

853.81 

167.10 

225.41 

5664.70 

225.41 

5515.89 

24.00 

4.01 

70



Load 

69.01 1 

Factor 


1000 

(MW) 

Starting 

Initial 


Storage 

Level 

0 0 

FRL (m) . 805 


0 

Design 


(m3/s) 



YEAR 

Head 

10% 

Loss 

Turbine 

Net storage 

discharge 

1985-1986 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

Static Head 

55.00 3 

storage 




Spill 


Level (H) 



1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 667.79 772.91 100.00 692.79 429.48 80.00 805.00 279.78 520.00 220.50 853.81 204.92 204.92 24.00 

Jun-85 805.00 80.00 676.55 783.04 185.00 756.55 432.41 80.00 805.00 350.63 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 677.66 784.32 185.00 757.66 432.41 80.00 805.00 351.91 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 750.55 868.69 185.00 830.55 432.41 80.00 805.00 436.28 520.00 256.50 1000.00 240.00 228.00 24.00 

Jul-85 805.00 80.00 983.82 1138.68 185.00 1063.82 432.41 80.00 805.00 706.26 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 975.70 1026.62 185.00 1055.70 432.41 80.00 805.00 594.21 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 763.22 883.36 185.00 843.22 432.41 80.00 805.00 450.94 520.00 256.50 1000.00 240.00 228.00 24.00 

Aug-85 805.00 80.00 831.78 962.71 185.00 911.78 432.41 80.00 805.00 530.30 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1076.69 1132.89 185.00 1156.69 432.41 80.00 805.00 700.47 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 797.34 922.84 185.00 877.34 432.41 80.00 805.00 490.43 520.00 256.50 1000.00 240.00 228.00 24.00 

Sep-85 805.00 80.00 751.66 869.97 185.00 831.66 432.41 80.00 805.00 437.56 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 510.96 591.38 185.00 590.96 432.41 80.00 805.00 158.97 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 402.82 466.23 185.00 482.82 432.41 80.00 805.00 33.82 520.00 256.50 1000.00 240.00 228.00 24.00 

Oct-85 805.00 80.00 364.77 422.19 185.00 444.77 422.19 80.00 805.00 0.00 520.00 256.50 976.35 234.32 228.00 23.43 

805.00 80.00 374.01 393.53 185.00 454.01 393.53 80.00 805.00 0.00 520.00 256.50 910.07 240.26 240.26 21.84 

805.00 80.00 336.29 389.23 185.00 416.29 389.23 80.00 805.00 0.00 520.00 256.50 900.13 216.03 216.03 21.60 

Nov-85 805.00 80.00 307.43 355.82 185.00 387.43 355.82 80.00 805.00 0.00 520.00 256.50 822.87 197.49 197.49 19.75 

805.00 80.00 253.71 293.64 185.00 333.71 293.64 80.00 805.00 0.00 520.00 256.50 679.08 162.98 162.98 16.30 

805.00 80.00 229.57 265.71 185.00 309.57 265.71 80.00 805.00 0.00 520.00 256.50 614.47 147.47 147.47 14.75 

Dec-85 805.00 80.00 197.60 228.71 185.00 277.60 228.71 80.00 805.00 0.00 520.00 256.50 528.91 126.94 126.94 12.69 

805.00 80.00 208.54 219.42 185.00 288.54 219.42 80.00 805.00 0.00 520.00 256.50 507.43 133.96 133.96 12.18 

805.00 80.00 166.78 193.04 185.00 246.78 193.04 80.00 805.00 0.00 520.00 256.50 446.42 107.14 107.14 10.71 

Jan-86 805.00 80.00 149.93 173.53 185.00 229.93 173.53 80.00 805.00 0.00 520.00 256.50 401.31 96.31 96.31 9.63 

805.00 80.00 142.91 150.37 185.00 222.91 150.37 80.00 805.00 0.00 520.00 256.50 347.74 91.80 91.80 8.35 

805.00 80.00 102.25 118.34 185.00 182.25 118.34 80.00 805.00 0.00 520.00 256.50 273.68 65.68 65.68 6.57 

Feb-86 805.00 80.00 96.43 111.61 185.00 176.43 111.61 80.00 805.00 0.00 520.00 256.50 258.12 61.95 61.95 6.19 

805.00 80.00 82.81 119.81 185.00 162.81 119.81 80.00 805.00 0.00 520.00 256.50 277.07 53.20 53.20 6.65 

805.00 80.00 98.84 114.40 185.00 178.84 114.40 80.00 805.00 0.00 520.00 256.50 264.56 63.49 63.49 6.35 

Mar-86 805.00 80.00 101.86 117.90 185.00 181.86 117.90 80.00 805.00 0.00 520.00 256.50 272.65 65.43 65.43 6.54 

805.00 80.00 97.52 102.61 185.00 177.52 102.61 80.00 805.00 0.00 520.00 256.50 237.29 62.64 62.64 5.69 

805.00 80.00 96.00 111.12 185.00 176.00 111.12 80.00 805.00 0.00 520.00 256.50 256.97 61.67 61.67 6.17 

Apr-86 805.00 80.00 119.67 138.50 185.00 199.67 138.50 80.00 805.00 0.00 520.00 256.50 320.30 76.87 76.87 7.69 

805.00 80.00 197.64 228.75 185.00 277.64 228.75 80.00 805.00 0.00 520.00 256.50 529.01 126.96 126.96 12.70 

805.00 80.00 165.46 191.50 185.00 245.46 191.50 80.00 805.00 0.00 520.00 256.50 442.87 106.29 106.29 10.63 

May-86 805.00 80.00 261.45 302.60 185.00 341.45 302.60 80.00 805.00 0.00 520.00 256.50 699.79 167.95 167.95 16.80 

805.00 80.00 327.47 344.56 185.00 407.47 402.43 25.00 765.00 0.00 520.00 256.50 930.66 245.69 245.69 22.34 

Total 

Inflows 

14345.47 ####### 

Av.Net 

Head 

255.50 237.29 6045.47 5892.75 5.69 

71



Load 

61.10 1 

Factor 


1000 

(MW) 

Starting 

Initial 


Storage 

Level 

0 0 

FRL (m) . 805 


0 

Design 


(m3/s) 



YEAR 

Head 

10% 

Loss 

Turbine 

Net storage 

discharge 

1986-1987 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

Static Head 

55.00 3 

storage 




Spill 


Level (H) 



1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 358.38 414.79 100.00 383.38 413.64 26.00 766.00 0.00 520.00 220.50 822.32 197.36 197.36 23.11 

Jun-86 766.00 26.00 525.03 607.67 102.00 551.03 430.35 80.00 805.00 114.82 520.00 221.40 859.05 206.17 206.17 24.00 

805.00 80.00 583.57 675.42 185.00 663.57 432.41 80.00 805.00 243.01 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 448.69 519.31 185.00 528.69 432.41 80.00 805.00 86.90 520.00 256.50 1000.00 240.00 228.00 24.00 

Jul-86 805.00 80.00 432.96 501.11 185.00 512.96 432.41 80.00 805.00 68.70 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 536.66 564.66 185.00 616.66 432.41 80.00 805.00 132.25 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 924.65 1070.20 185.00 1004.65 432.41 80.00 805.00 637.79 520.00 256.50 1000.00 240.00 228.00 24.00 

Aug-86 805.00 80.00 784.95 908.51 185.00 864.95 432.41 80.00 805.00 476.10 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1124.69 1183.38 185.00 1204.69 432.41 80.00 805.00 750.97 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 877.62 1015.76 185.00 957.62 432.41 80.00 805.00 583.35 520.00 256.50 1000.00 240.00 228.00 24.00 

Sep-86 805.00 80.00 1314.33 1521.22 185.00 1394.33 432.41 80.00 805.00 1088.80 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 672.19 777.99 185.00 752.19 432.41 80.00 805.00 345.58 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 525.65 608.39 185.00 605.65 432.41 80.00 805.00 175.98 520.00 256.50 1000.00 240.00 228.00 24.00 

Oct-86 805.00 80.00 366.11 423.74 185.00 446.11 423.74 80.00 805.00 0.00 520.00 256.50 979.95 235.19 228.00 23.52 

805.00 80.00 225.68 237.46 185.00 305.68 237.46 80.00 805.00 0.00 520.00 256.50 549.14 144.97 144.97 13.18 

805.00 80.00 139.12 161.02 185.00 219.12 161.02 80.00 805.00 0.00 520.00 256.50 372.38 89.37 89.37 8.94 

Nov-86 805.00 80.00 151.87 175.78 185.00 231.87 175.78 80.00 805.00 0.00 520.00 256.50 406.51 97.56 97.56 9.76 

805.00 80.00 118.28 136.90 185.00 198.28 136.90 80.00 805.00 0.00 520.00 256.50 316.60 75.98 75.98 7.60 

805.00 80.00 112.44 130.14 185.00 192.44 130.14 80.00 805.00 0.00 520.00 256.50 300.96 72.23 72.23 7.22 

Dec-86 805.00 80.00 101.76 117.78 185.00 181.76 117.78 80.00 805.00 0.00 520.00 256.50 272.38 65.37 65.37 6.54 

805.00 80.00 109.16 114.86 185.00 189.16 114.86 80.00 805.00 0.00 520.00 256.50 265.62 70.12 70.12 6.37 

805.00 80.00 64.64 74.82 185.00 144.64 74.82 80.00 805.00 0.00 520.00 256.50 173.03 41.53 41.53 4.15 

Jan-87 805.00 80.00 60.25 69.73 185.00 140.25 69.73 80.00 805.00 0.00 520.00 256.50 161.25 38.70 38.70 3.87 

805.00 80.00 61.73 64.95 185.00 141.73 64.95 80.00 805.00 0.00 520.00 256.50 150.22 39.66 39.66 3.61 

805.00 80.00 52.71 61.01 185.00 132.71 61.01 80.00 805.00 0.00 520.00 256.50 141.09 33.86 33.86 3.39 

Feb-87 805.00 80.00 51.25 59.31 185.00 131.25 59.31 80.00 805.00 0.00 520.00 256.50 137.17 32.92 32.92 3.29 

805.00 80.00 56.45 81.67 185.00 136.45 81.67 80.00 805.00 0.00 520.00 256.50 188.87 36.26 36.26 4.53 

805.00 80.00 73.47 85.03 185.00 153.47 85.03 80.00 805.00 0.00 520.00 256.50 196.65 47.20 47.20 4.72 

Mar-87 805.00 80.00 85.21 98.62 185.00 165.21 98.62 80.00 805.00 0.00 520.00 256.50 228.08 54.74 54.74 5.47 

805.00 80.00 69.70 73.33 185.00 149.70 73.33 80.00 805.00 0.00 520.00 256.50 169.59 44.77 44.77 4.07 

805.00 80.00 164.22 190.07 185.00 244.22 190.07 80.00 805.00 0.00 520.00 256.50 439.55 105.49 105.49 10.55 

Apr-87 805.00 80.00 334.63 387.31 185.00 414.63 432.41 41.03 780.73 0.00 520.00 256.50 1000.00 240.00 228.00 24.00 

780.73 41.03 309.36 358.06 133.32 350.39 376.58 25.03 765.03 0.00 520.00 234.66 796.73 191.22 191.22 20.40 

765.03 25.03 212.29 245.71 100.06 237.32 245.74 25.00 765.00 0.00 520.00 220.53 488.60 117.26 117.26 13.73 

May-87 765.00 25.00 291.04 336.85 100.00 316.04 336.85 25.00 765.00 0.00 520.00 220.50 669.67 160.72 160.72 18.82 

765.00 25.00 545.32 573.78 100.00 570.32 429.48 25.00 765.00 144.31 520.00 220.50 853.81 225.41 225.41 24.00 

Total 

Inflows 

12866.07 9777.83 

Av.Net 

Head 

250.92 137.17 5352.07 5198.48 3.29 

72



Load 

66.28 1 

Factor 


1000 

(MW) 

Starting 

Initial 


Storage 

Level 

0 

FRL (m) . 805 


Reservoir 

0 0 

Design 


(m3/s) 



YEAR 

Head 

10% 

Loss 

Turbine 

Net storage 

discharge 

1987-1988 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

Static Head 

55.00 3 

storage 




Spill 


Level (H) 



1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 871.52 1008.70 100.00 896.52 429.48 80.00 805.00 515.56 520.00 220.50 853.81 204.92 204.92 24.00 

Jun-87 805.00 80.00 1299.28 1503.80 185.00 1379.28 432.41 80.00 805.00 1071.38 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1363.17 1577.75 185.00 1443.17 432.41 80.00 805.00 1145.33 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1635.87 1893.37 185.00 1715.87 432.41 80.00 805.00 1460.96 520.00 256.50 1000.00 240.00 228.00 24.00 

Jul-87 805.00 80.00 1117.28 1293.15 185.00 1197.28 432.41 80.00 805.00 860.74 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1825.41 1920.68 185.00 1905.41 432.41 80.00 805.00 1488.27 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 2058.40 2382.40 185.00 2138.40 432.41 80.00 805.00 1949.99 520.00 256.50 1000.00 240.00 228.00 24.00 

Aug-87 805.00 80.00 2397.15 2774.47 185.00 2477.15 432.41 80.00 805.00 2342.06 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1254.29 1319.75 185.00 1334.29 432.41 80.00 805.00 887.33 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 1060.76 1227.73 185.00 1140.76 432.41 80.00 805.00 795.32 520.00 256.50 1000.00 240.00 228.00 24.00 

Sep-87 805.00 80.00 649.49 751.73 185.00 729.49 432.41 80.00 805.00 319.31 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 811.34 939.06 185.00 891.34 432.41 80.00 805.00 506.64 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 527.06 610.02 185.00 607.06 432.41 80.00 805.00 177.61 520.00 256.50 1000.00 240.00 228.00 24.00 

Oct-87 805.00 80.00 417.87 483.64 185.00 497.87 432.41 80.00 805.00 51.23 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 419.42 441.31 185.00 499.42 432.41 80.00 805.00 8.89 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 265.32 307.08 185.00 345.32 307.08 80.00 805.00 0.00 520.00 256.50 710.15 170.44 170.44 17.04 

Nov-87 805.00 80.00 194.44 225.05 185.00 274.44 225.05 80.00 805.00 0.00 520.00 256.50 520.44 124.91 124.91 12.49 

805.00 80.00 162.36 187.92 185.00 242.36 187.92 80.00 805.00 0.00 520.00 256.50 434.59 104.30 104.30 10.43 

805.00 80.00 139.76 161.76 185.00 219.76 161.76 80.00 805.00 0.00 520.00 256.50 374.09 89.78 89.78 8.98 

Dec-87 805.00 80.00 128.76 149.03 185.00 208.76 149.03 80.00 805.00 0.00 520.00 256.50 344.64 82.71 82.71 8.27 

805.00 80.00 121.72 128.08 185.00 201.72 128.08 80.00 805.00 0.00 520.00 256.50 296.19 78.19 78.19 7.11 

805.00 80.00 97.59 112.96 185.00 177.59 112.96 80.00 805.00 0.00 520.00 256.50 261.22 62.69 62.69 6.27 

Jan-88 805.00 80.00 98.87 114.44 185.00 178.87 114.44 80.00 805.00 0.00 520.00 256.50 264.65 63.51 63.51 6.35 

805.00 80.00 99.67 104.87 185.00 179.67 104.87 80.00 805.00 0.00 520.00 256.50 242.53 64.03 64.03 5.82 

805.00 80.00 77.51 89.71 185.00 157.51 89.71 80.00 805.00 0.00 520.00 256.50 207.45 49.79 49.79 4.98 

Feb-88 805.00 80.00 103.21 119.45 185.00 183.21 119.45 80.00 805.00 0.00 520.00 256.50 276.24 66.30 66.30 6.63 

805.00 80.00 169.00 244.50 185.00 249.00 244.50 80.00 805.00 0.00 520.00 256.50 565.43 108.56 108.56 13.57 

805.00 80.00 83.68 96.85 185.00 163.68 96.85 80.00 805.00 0.00 520.00 256.50 223.98 53.76 53.76 5.38 

Mar-88 805.00 80.00 125.98 145.81 185.00 205.98 145.81 80.00 805.00 0.00 520.00 256.50 337.21 80.93 80.93 8.09 

805.00 80.00 168.47 177.26 185.00 248.47 177.26 80.00 805.00 0.00 520.00 256.50 409.94 108.22 108.22 9.84 

805.00 80.00 141.12 163.33 185.00 221.12 163.33 80.00 805.00 0.00 520.00 256.50 377.73 90.65 90.65 9.07 

Apr-88 805.00 80.00 205.83 238.23 185.00 285.83 300.73 26.00 766.00 0.00 520.00 256.50 695.48 166.91 166.91 16.69 

766.00 26.00 249.02 288.21 102.00 275.02 289.37 25.00 765.00 0.00 520.00 221.40 577.62 138.63 138.63 16.14 

765.00 25.00 198.76 230.05 100.00 223.76 230.05 25.00 765.00 0.00 520.00 220.50 457.34 109.76 109.76 12.86 

May-88 765.00 25.00 235.58 272.66 100.00 260.58 272.66 25.00 765.00 0.00 520.00 220.50 542.06 130.10 130.10 15.24 

765.00 25.00 507.50 533.99 100.00 532.50 429.48 25.00 765.00 104.51 520.00 220.50 853.81 225.41 225.41 24.00 

Total 

Inflows 

21282.46 ####### 

Av.Net 

Head 

251.53 207.45 5806.51 5634.91 4.98 

73



Load 

80.11 1 

Factor 


1000 

(MW) 

Starting 

Initial 


Storage 

Level 

0 

FRL (m) . 805 


Reservoir 

0 0 

Design 


(m3/s) 



YEAR 

Head 

10% 

Loss 

Turbine 

Net storage 

discharge 

1988-1989 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

Static Head 

55.00 3 

storage 




Spill 


Level (H) 



1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 323.52 374.44 100.00 348.52 373.28 26.00 766.00 0.00 520.00 220.50 742.10 178.10 178.10 20.86 

Jun-88 766.00 26.00 732.63 847.95 102.00 758.63 430.35 80.00 805.00 355.10 520.00 221.40 859.05 206.17 206.17 24.00 

805.00 80.00 705.11 816.10 185.00 785.11 432.41 80.00 805.00 383.69 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1021.29 1182.05 185.00 1101.29 432.41 80.00 805.00 749.63 520.00 256.50 1000.00 240.00 228.00 24.00 

Jul-88 805.00 80.00 788.82 912.98 185.00 868.82 432.41 80.00 805.00 480.57 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1086.01 1142.69 185.00 1166.01 432.41 80.00 805.00 710.27 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 725.02 839.15 185.00 805.02 432.41 80.00 805.00 406.73 520.00 256.50 1000.00 240.00 228.00 24.00 

Aug-88 805.00 80.00 1503.87 1740.60 185.00 1583.87 432.41 80.00 805.00 1308.18 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 2059.51 2166.99 185.00 2139.51 432.41 80.00 805.00 1734.58 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 1523.75 1763.60 185.00 1603.75 432.41 80.00 805.00 1331.18 520.00 256.50 1000.00 240.00 228.00 24.00 

Sep-88 805.00 80.00 974.67 1128.10 185.00 1054.67 432.41 80.00 805.00 695.68 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 906.24 1048.89 185.00 986.24 432.41 80.00 805.00 616.48 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 910.48 1053.79 185.00 990.48 432.41 80.00 805.00 621.38 520.00 256.50 1000.00 240.00 228.00 24.00 

Oct-88 805.00 80.00 490.41 567.61 185.00 570.41 432.41 80.00 805.00 135.19 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 499.66 525.74 185.00 579.66 432.41 80.00 805.00 93.33 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 343.39 397.45 185.00 423.39 397.45 80.00 805.00 0.00 520.00 256.50 919.14 220.59 220.59 22.06 

Nov-88 805.00 80.00 305.31 353.37 185.00 385.31 353.37 80.00 805.00 0.00 520.00 256.50 817.21 196.13 196.13 19.61 

805.00 80.00 281.26 325.54 185.00 361.26 325.54 80.00 805.00 0.00 520.00 256.50 752.84 180.68 180.68 18.07 

805.00 80.00 241.39 279.38 185.00 321.39 279.38 80.00 805.00 0.00 520.00 256.50 646.10 155.06 155.06 15.51 

Dec-88 805.00 80.00 201.32 233.00 185.00 281.32 233.00 80.00 805.00 0.00 520.00 256.50 538.85 129.32 129.32 12.93 

805.00 80.00 203.76 214.39 185.00 283.76 214.39 80.00 805.00 0.00 520.00 256.50 495.80 130.89 130.89 11.90 

805.00 80.00 262.67 304.02 185.00 342.67 304.02 80.00 805.00 0.00 520.00 256.50 703.07 168.74 168.74 16.87 

Jan-89 805.00 80.00 245.31 283.92 185.00 325.31 283.92 80.00 805.00 0.00 520.00 256.50 656.60 157.58 157.58 15.76 

805.00 80.00 255.36 268.69 185.00 335.36 268.69 80.00 805.00 0.00 520.00 256.50 621.38 164.04 164.04 14.91 

805.00 80.00 177.63 205.58 185.00 257.63 205.58 80.00 805.00 0.00 520.00 256.50 475.44 114.10 114.10 11.41 

Feb-89 805.00 80.00 183.48 212.36 185.00 263.48 212.36 80.00 805.00 0.00 520.00 256.50 491.11 117.87 117.87 11.79 

805.00 80.00 151.75 219.54 185.00 231.75 219.54 80.00 805.00 0.00 520.00 256.50 507.71 97.48 97.48 12.18 

805.00 80.00 180.13 208.49 185.00 260.13 208.49 80.00 805.00 0.00 520.00 256.50 482.15 115.72 115.72 11.57 

Mar-89 805.00 80.00 211.87 245.22 185.00 291.87 307.72 26.00 766.00 0.00 520.00 256.50 711.63 170.79 170.79 17.08 

766.00 26.00 219.88 231.35 102.00 245.88 232.41 25.00 765.00 0.00 520.00 221.40 463.92 122.47 122.47 12.96 

765.00 25.00 207.89 240.61 100.00 232.89 240.61 25.00 765.00 0.00 520.00 220.50 478.34 114.80 114.80 13.45 

Apr-89 765.00 25.00 246.19 284.94 100.00 271.19 284.94 25.00 765.00 0.00 520.00 220.50 566.47 135.95 135.95 15.92 

765.00 25.00 490.38 567.57 100.00 515.38 429.48 80.00 805.00 74.44 520.00 220.50 853.81 204.92 204.92 24.00 

805.00 80.00 478.99 554.39 185.00 558.99 432.41 80.00 805.00 121.98 520.00 256.50 1000.00 240.00 228.00 24.00 

May-89 805.00 80.00 434.57 502.97 185.00 514.57 432.41 80.00 805.00 70.56 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 688.34 724.26 185.00 768.34 432.41 25.00 765.00 349.72 520.00 256.50 1000.00 264.00 250.80 24.00 

Total 

Inflows 

20261.85 ####### 

Av.Net 

Head 

250.55 463.92 7017.42 6820.62 11.41 

74



Load 

89.73 1 

Factor 


1000 

(MW) 

Starting 

Initial 


Storage 

Level 

0 

FRL (m) . 805 


Reservoir 

0 0 

Design 


(m3/s) 



YEAR 

Head 

10% 

Loss 

Turbine 

Net storage 

discharge 

1989-1990 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

Static Head 

55.00 3 

storage 




Spill 


Level (H) 



1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 564.41 653.25 100.00 589.41 429.48 80.00 805.00 160.12 520.00 220.50 853.81 204.92 204.92 24.00 

Jun-89 805.00 80.00 706.84 818.10 185.00 786.84 432.41 80.00 805.00 385.69 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 835.92 967.50 185.00 915.92 432.41 80.00 805.00 535.08 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 928.70 1074.89 185.00 1008.70 432.41 80.00 805.00 642.47 520.00 256.50 1000.00 240.00 228.00 24.00 

Jul-89 805.00 80.00 886.62 1026.18 185.00 966.62 432.41 80.00 805.00 593.76 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 900.27 947.25 185.00 980.27 432.41 80.00 805.00 514.84 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 698.77 808.77 185.00 778.77 432.41 80.00 805.00 376.35 520.00 256.50 1000.00 240.00 228.00 24.00 

Aug-89 805.00 80.00 795.33 920.52 185.00 875.33 432.41 80.00 805.00 488.10 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 815.23 857.77 185.00 895.23 432.41 80.00 805.00 425.36 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 876.05 1013.95 185.00 956.05 432.41 80.00 805.00 581.54 520.00 256.50 1000.00 240.00 228.00 24.00 

Sep-89 805.00 80.00 891.18 1031.46 185.00 971.18 432.41 80.00 805.00 599.05 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 882.81 1021.77 185.00 962.81 432.41 80.00 805.00 589.36 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 708.15 819.61 185.00 788.15 432.41 80.00 805.00 387.20 520.00 256.50 1000.00 240.00 228.00 24.00 

Oct-89 805.00 80.00 591.61 684.73 185.00 671.61 432.41 80.00 805.00 252.32 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 530.56 558.25 185.00 610.56 432.41 80.00 805.00 125.84 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 431.97 499.96 185.00 511.97 432.41 80.00 805.00 67.55 520.00 256.50 1000.00 240.00 228.00 24.00 

Nov-89 805.00 80.00 417.13 482.79 185.00 497.13 432.41 80.00 805.00 50.37 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 401.11 464.25 185.00 481.11 432.41 80.00 805.00 31.84 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 328.45 380.15 185.00 408.45 380.15 80.00 805.00 0.00 520.00 256.50 879.13 210.99 210.99 21.10 

Dec-89 805.00 80.00 318.19 368.28 185.00 398.19 368.28 80.00 805.00 0.00 520.00 256.50 851.69 204.41 204.41 20.44 

805.00 80.00 348.85 367.05 185.00 428.85 367.05 80.00 805.00 0.00 520.00 256.50 848.85 224.10 224.10 20.37 

805.00 80.00 248.40 287.50 185.00 328.40 287.50 80.00 805.00 0.00 520.00 256.50 664.87 159.57 159.57 15.96 

Jan-90 805.00 80.00 228.81 264.83 185.00 308.81 264.83 80.00 805.00 0.00 520.00 256.50 612.45 146.99 146.99 14.70 

805.00 80.00 245.82 258.65 185.00 325.82 258.65 80.00 805.00 0.00 520.00 256.50 598.16 157.91 157.91 14.36 

805.00 80.00 260.03 300.96 185.00 340.03 300.96 80.00 805.00 0.00 520.00 256.50 696.00 167.04 167.04 16.70 

Feb-90 805.00 80.00 231.73 268.21 185.00 311.73 268.21 80.00 805.00 0.00 520.00 256.50 620.26 148.86 148.86 14.89 

805.00 80.00 205.32 297.05 185.00 285.32 322.23 62.60 795.16 0.00 520.00 256.50 745.19 143.08 143.08 17.88 

795.16 62.60 253.29 293.16 162.90 315.89 293.16 62.60 795.16 0.00 520.00 247.64 654.56 157.10 157.10 15.71 

Mar-90 795.16 62.60 252.20 291.90 162.90 314.80 291.90 62.60 795.16 0.00 520.00 247.64 651.75 156.42 156.42 15.64 

795.16 62.60 348.05 366.21 162.90 410.64 366.21 62.60 795.16 0.00 520.00 247.64 817.65 215.86 215.86 19.62 

795.16 62.60 391.01 452.56 162.90 453.60 432.41 80.00 805.00 0.00 520.00 247.64 965.47 231.71 228.00 23.17 

Apr-90 805.00 80.00 371.13 429.55 185.00 451.13 432.41 77.53 803.68 0.00 520.00 256.50 1000.00 240.00 228.00 24.00 

803.68 77.53 447.81 518.30 182.35 525.34 434.41 80.00 805.00 81.03 520.00 255.31 999.95 239.99 228.00 24.00 

805.00 80.00 354.05 409.78 185.00 434.05 432.41 60.45 793.87 0.00 520.00 256.50 1000.00 240.00 228.00 24.00 

May-90 793.87 60.45 342.53 396.45 159.68 402.98 436.96 25.45 765.45 0.00 520.00 246.48 971.05 233.05 228.00 23.31 

765.45 25.45 873.03 918.59 100.90 898.48 429.87 25.00 765.00 489.19 520.00 220.90 856.16 226.03 226.03 24.00 

Total 

Inflows 

18911.37 ####### 

Av.Net 

Head 

253.22 598.16 7860.01 7607.66 14.36 

75



Load 

86.11 1 

Factor 


1000 

(MW) 

Starting 

Initial 


Storage 

Level 

0 

FRL (m) . 805 


Reservoir 

0 0 

Design 


(m3/s) 



YEAR 

Head 

10% 

Loss 

Turbine 

Net storage 

discharge 

1990-1991 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

Static Head 

55.00 3 

storage 




Spill 


Level (H) 



1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 966.16 1118.24 100.00 991.16 429.48 80.00 805.00 625.11 520.00 220.50 853.81 204.91 204.91 24.00 

Jun-90 805.00 80.00 1215.13 1406.40 185.00 1295.13 432.41 80.00 805.00 973.99 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1055.08 1221.16 185.00 1135.08 432.41 80.00 805.00 788.75 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 840.88 973.24 185.00 920.88 432.41 80.00 805.00 540.83 520.00 256.50 1000.00 240.00 228.00 24.00 

Jul-90 805.00 80.00 900.89 1042.70 185.00 980.89 432.41 80.00 805.00 610.28 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1452.22 1528.01 185.00 1532.22 432.41 80.00 805.00 1095.60 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 988.12 1143.66 185.00 1068.12 432.41 80.00 805.00 711.25 520.00 256.50 1000.00 240.00 228.00 24.00 

Aug-90 805.00 80.00 821.55 950.87 185.00 901.55 432.41 80.00 805.00 518.46 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 525.75 553.18 185.00 605.75 432.41 80.00 805.00 120.77 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 361.90 418.87 185.00 441.90 432.41 68.30 798.58 0.00 520.00 256.50 1000.00 240.00 228.00 24.00 

Sep-90 798.58 68.30 355.43 411.38 171.45 423.73 442.38 41.52 781.08 0.00 520.00 250.72 1000.00 240.00 228.00 24.00 

781.08 41.52 1209.85 1400.28 133.95 1251.36 443.35 80.00 805.00 912.39 520.00 234.97 939.25 225.42 225.42 24.00 

805.00 80.00 1058.59 1225.22 185.00 1138.59 432.41 80.00 805.00 792.81 520.00 256.50 1000.00 240.00 228.00 24.00 

Oct-90 805.00 80.00 956.54 1107.11 185.00 1036.54 432.41 80.00 805.00 674.70 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 516.96 543.94 185.00 596.96 432.41 80.00 805.00 111.53 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 411.63 476.43 185.00 491.63 432.41 80.00 805.00 44.02 520.00 256.50 1000.00 240.00 228.00 24.00 

Nov-90 805.00 80.00 369.62 427.80 185.00 449.62 432.41 76.02 802.87 0.00 520.00 256.50 1000.00 240.00 228.00 24.00 

802.87 76.02 330.19 382.17 180.73 406.21 378.01 79.61 804.79 0.00 520.00 254.58 867.65 208.24 208.24 20.82 

804.79 79.61 309.24 357.92 184.58 388.85 359.49 78.25 804.06 0.00 520.00 256.31 830.75 199.38 199.38 19.94 

Dec-90 804.06 78.25 281.88 326.25 183.12 360.12 348.54 58.98 792.99 0.00 520.00 255.65 803.39 192.81 192.81 19.28 

792.99 58.98 274.96 289.31 157.48 333.95 294.88 53.69 789.78 0.00 520.00 245.69 653.21 172.45 172.45 15.68 

789.78 53.69 235.35 272.40 149.60 289.04 299.93 29.90 769.90 0.00 520.00 242.80 656.58 157.58 157.58 15.97 

Jan-91 769.90 29.90 230.48 266.76 109.80 260.38 290.67 9.24 740.81 0.00 520.00 224.91 589.42 141.46 141.46 16.08 

740.81 9.24 247.02 259.91 53.27 256.26 210.71 56.00 791.20 0.00 520.00 198.73 377.54 99.67 99.67 12.40 

791.20 56.00 215.79 249.75 153.00 271.79 232.80 70.65 799.99 0.00 520.00 244.08 512.31 122.96 122.96 12.37 

Feb-91 799.99 70.65 216.63 250.73 174.98 287.27 325.40 6.13 733.62 0.00 520.00 251.99 739.28 177.43 177.43 17.74 

733.62 6.13 175.62 254.08 37.62 181.75 255.95 4.84 730.62 0.00 520.00 192.26 443.66 85.18 85.18 15.32 

730.62 4.84 270.23 312.77 31.10 275.07 302.25 13.93 751.70 0.00 520.00 189.56 516.55 123.97 123.97 18.22 

Mar-91 751.70 13.93 300.98 348.35 76.95 314.91 336.97 23.77 764.18 0.00 520.00 208.53 633.54 152.05 152.05 19.36 

764.18 23.77 327.60 344.69 99.18 351.36 347.49 21.11 762.40 0.00 520.00 219.76 688.50 181.76 181.76 19.45 

762.40 21.11 487.58 564.33 97.40 508.69 427.19 80.00 805.00 68.97 520.00 218.16 840.27 201.66 201.66 24.00 

Apr-91 805.00 80.00 600.56 695.09 185.00 680.56 432.41 80.00 805.00 262.68 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 648.32 750.37 185.00 728.32 432.41 80.00 805.00 317.96 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 722.54 836.27 185.00 802.54 432.41 80.00 805.00 403.86 520.00 256.50 1000.00 240.00 228.00 24.00 

May-91 805.00 80.00 697.81 807.65 185.00 777.81 432.41 80.00 805.00 375.24 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 677.20 712.54 185.00 757.20 432.41 25.00 765.00 338.00 520.00 256.50 1000.00 264.00 250.80 24.00 

Total 

Inflows 

21256.30 ####### 

Av.Net 

Head 

243.96 377.54 7542.92 7298.14 12.37 

76



Load 

81.20 

Factor 


(MW) 

Starting 


Level 

1 

1000 

Initial 

Storage 

0 

FRL (m) . 805 


Reservoir 

0 0 

Design 


(m3/s) 



YEAR 

Head 

10% 

Loss 

Turbine 

Net storage 

discharge 

1991-1992 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

Static Head 

55.00 3 

storage 




Spill 


Level (H) 



1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 759.63 879.20 100.00 784.63 429.48 80.00 805.00 386.07 520.00 220.50 853.81 204.91 204.91 24.00 

Jun-91 805.00 80.00 678.62 785.44 185.00 758.62 432.41 80.00 805.00 353.03 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 740.22 856.74 185.00 820.22 432.41 80.00 805.00 424.33 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1343.70 1555.20 185.00 1423.70 432.41 80.00 805.00 1122.79 520.00 256.50 1000.00 240.00 228.00 24.00 

Jul-91 805.00 80.00 1204.11 1393.64 185.00 1284.11 432.41 80.00 805.00 961.23 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1067.60 1123.31 185.00 1147.60 432.41 80.00 805.00 690.90 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 947.60 1096.76 185.00 1027.60 432.41 80.00 805.00 664.35 520.00 256.50 1000.00 240.00 228.00 24.00 

Aug-91 805.00 80.00 903.11 1045.27 185.00 983.11 432.41 80.00 805.00 612.86 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1056.93 1112.09 185.00 1136.93 432.41 80.00 805.00 679.68 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 735.77 851.59 185.00 815.77 432.41 80.00 805.00 419.18 520.00 256.50 1000.00 240.00 228.00 24.00 

Sep-91 805.00 80.00 564.92 653.84 185.00 644.92 432.41 80.00 805.00 221.43 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 517.08 598.47 185.00 597.08 432.41 80.00 805.00 166.06 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 500.21 578.95 185.00 580.21 432.41 80.00 805.00 146.54 520.00 256.50 1000.00 240.00 228.00 24.00 

Oct-91 805.00 80.00 560.08 648.24 185.00 640.08 432.41 80.00 805.00 215.83 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 511.24 537.92 185.00 591.24 432.41 80.00 805.00 105.51 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 324.48 375.56 185.00 404.48 432.41 30.88 770.88 0.00 520.00 256.50 1000.00 240.00 228.00 24.00 

Nov-91 770.88 30.88 314.75 364.30 111.94 345.63 374.54 22.03 763.02 0.00 520.00 225.79 762.47 182.99 182.99 20.68 

763.02 22.03 306.12 354.30 98.02 328.15 320.14 51.54 788.25 0.00 520.00 218.72 631.30 151.51 151.51 17.96 

788.25 51.54 249.42 288.68 146.84 300.96 313.20 30.36 770.36 0.00 520.00 241.42 681.72 163.61 163.61 16.73 

Dec-91 770.36 30.36 246.63 285.45 110.79 276.99 290.67 25.85 765.85 0.00 520.00 225.32 590.51 141.72 141.72 16.07 

765.85 25.85 256.94 270.35 101.70 282.79 263.32 32.54 772.54 0.00 520.00 221.26 525.29 138.68 138.68 14.69 

772.54 32.54 204.79 237.02 115.58 237.33 242.06 28.18 768.18 0.00 520.00 227.28 496.03 119.05 119.05 13.32 

Jan-92 768.18 28.18 198.71 229.99 106.37 226.90 232.80 25.76 765.76 0.00 520.00 223.37 468.83 112.52 112.52 12.93 

765.76 25.76 224.56 236.28 101.52 250.32 210.71 50.06 787.19 0.00 520.00 221.18 420.19 110.93 110.93 11.76 

787.19 50.06 218.50 252.90 144.94 268.56 232.80 67.42 798.06 0.00 520.00 240.47 504.73 121.14 121.14 12.46 

Feb-92 798.06 67.42 201.50 233.21 170.14 268.92 232.80 67.78 798.27 0.00 520.00 250.25 525.26 126.06 126.06 12.61 

798.27 67.78 155.97 225.65 170.68 223.75 227.02 66.84 797.70 0.00 520.00 250.44 512.60 98.42 98.42 12.30 

797.70 66.84 178.02 206.04 169.26 244.85 232.80 43.71 782.65 0.00 520.00 249.93 524.60 125.90 125.90 12.59 

Mar-92 782.65 43.71 182.57 211.30 136.77 226.28 232.80 25.14 765.14 0.00 520.00 236.39 496.16 119.08 119.08 12.56 

765.14 25.14 273.62 287.90 100.27 298.75 230.70 79.50 804.73 0.00 520.00 220.62 458.89 121.15 121.15 12.89 

804.73 79.50 280.49 324.65 184.46 359.99 324.13 79.94 804.97 0.00 520.00 256.26 748.88 179.73 179.73 17.97 

Apr-92 804.97 79.94 392.25 453.99 184.94 472.19 432.46 80.00 805.00 21.46 520.00 256.47 1000.00 240.00 228.00 24.00 

805.00 80.00 396.62 459.05 185.00 476.62 432.41 80.00 805.00 26.64 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 438.49 507.51 185.00 518.49 432.41 80.00 805.00 75.10 520.00 256.50 1000.00 240.00 228.00 24.00 

May-92 805.00 80.00 508.33 588.34 185.00 588.33 432.41 80.00 805.00 155.93 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 665.39 700.12 185.00 745.39 432.41 25.00 765.00 325.58 520.00 256.50 1000.00 264.00 250.80 24.00 

Total 

Inflows 

18308.97 ####### 

Av.Net 

Head 

246.09 420.19 7113.39 6868.61 11.76 

77



Load 

72.32 1 

Factor 


1000 

(MW) 

Starting 

Initial 


Storage 

Level 

0 

FRL (m) . 805 


Reservoir 

0 0 

Design 


(m3/s) 



YEAR 

Head 

10% 

Loss 

Turbine 

Net storage 

discharge 

1992-1993 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

Static Head 

55.00 3 

storage 




Spill 


Level (H) 



1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 639.25 739.87 100.00 664.25 429.48 80.00 805.00 246.73 520.00 220.50 853.81 204.92 204.92 24.00 

Jun-92 805.00 80.00 667.22 772.24 185.00 747.22 432.41 80.00 805.00 339.83 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1037.43 1200.73 185.00 1117.43 432.41 80.00 805.00 768.32 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 912.97 1056.68 185.00 992.97 432.41 80.00 805.00 624.27 520.00 256.50 1000.00 240.00 228.00 24.00 

Jul-92 805.00 80.00 838.12 970.05 185.00 918.12 432.41 80.00 805.00 537.63 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 974.49 1025.35 185.00 1054.49 432.41 80.00 805.00 592.93 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 838.57 970.57 185.00 918.57 432.41 80.00 805.00 538.15 520.00 256.50 1000.00 240.00 228.00 24.00 

Aug-92 805.00 80.00 804.09 930.66 185.00 884.09 432.41 80.00 805.00 498.24 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 936.12 984.97 185.00 1016.12 432.41 80.00 805.00 552.56 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 763.85 884.08 185.00 843.85 432.41 80.00 805.00 451.67 520.00 256.50 1000.00 240.00 228.00 24.00 

Sep-92 805.00 80.00 517.41 598.85 185.00 597.41 432.41 80.00 805.00 166.44 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 383.86 444.29 185.00 463.86 432.41 80.00 805.00 11.87 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 384.19 444.67 185.00 464.19 432.41 80.00 805.00 12.25 520.00 256.50 1000.00 240.00 228.00 24.00 

Oct-92 805.00 80.00 347.51 402.21 185.00 427.51 402.21 80.00 805.00 0.00 520.00 256.50 930.14 223.23 223.23 22.32 

805.00 80.00 319.02 335.67 185.00 399.02 335.67 80.00 805.00 0.00 520.00 256.50 776.26 204.93 204.93 18.63 

805.00 80.00 224.80 260.19 185.00 304.80 260.19 80.00 805.00 0.00 520.00 256.50 601.71 144.41 144.41 14.44 

Nov-92 805.00 80.00 217.72 251.99 185.00 297.72 251.99 80.00 805.00 0.00 520.00 256.50 582.74 139.86 139.86 13.99 

805.00 80.00 202.35 234.20 185.00 282.35 234.20 80.00 805.00 0.00 520.00 256.50 541.62 129.99 129.99 13.00 

805.00 80.00 197.12 228.15 185.00 277.12 228.15 80.00 805.00 0.00 520.00 256.50 527.63 126.63 126.63 12.66 

Dec-92 805.00 80.00 183.45 212.33 185.00 263.45 212.33 80.00 805.00 0.00 520.00 256.50 491.03 117.85 117.85 11.78 

805.00 80.00 193.45 203.55 185.00 273.45 203.55 80.00 805.00 0.00 520.00 256.50 470.72 124.27 124.27 11.30 

805.00 80.00 187.54 217.06 185.00 267.54 217.06 80.00 805.00 0.00 520.00 256.50 501.97 120.47 120.47 12.05 

Jan-93 805.00 80.00 191.63 221.80 185.00 271.63 221.80 80.00 805.00 0.00 520.00 256.50 512.93 123.10 123.10 12.31 

805.00 80.00 201.79 212.32 185.00 281.79 212.32 80.00 805.00 0.00 520.00 256.50 491.02 129.63 129.63 11.78 

805.00 80.00 176.13 203.85 185.00 256.13 203.85 80.00 805.00 0.00 520.00 256.50 471.43 113.14 113.14 11.31 

Feb-93 805.00 80.00 208.88 241.76 185.00 288.88 241.76 80.00 805.00 0.00 520.00 256.50 559.10 134.18 134.18 13.42 

805.00 80.00 155.55 225.04 185.00 235.55 225.04 80.00 805.00 0.00 520.00 256.50 520.43 99.92 99.92 12.49 

805.00 80.00 177.82 205.81 185.00 257.82 205.81 80.00 805.00 0.00 520.00 256.50 475.95 114.23 114.23 11.42 

Mar-93 805.00 80.00 215.67 249.61 185.00 295.67 249.61 80.00 805.00 0.00 520.00 256.50 577.26 138.54 138.54 13.85 

805.00 80.00 240.93 253.50 185.00 320.93 253.50 80.00 805.00 0.00 520.00 256.50 586.24 154.77 154.77 14.07 

805.00 80.00 192.50 222.80 185.00 272.50 222.80 80.00 805.00 0.00 520.00 256.50 515.25 123.66 123.66 12.37 

Apr-93 805.00 80.00 192.73 223.07 185.00 272.73 223.07 80.00 805.00 0.00 520.00 256.50 515.87 123.81 123.81 12.38 

805.00 80.00 220.67 255.40 185.00 300.67 255.40 80.00 805.00 0.00 520.00 256.50 590.64 141.75 141.75 14.18 

805.00 80.00 216.32 250.37 185.00 296.32 250.37 80.00 805.00 0.00 520.00 256.50 579.01 138.96 138.96 13.90 

May-93 805.00 80.00 226.67 262.35 185.00 306.67 262.35 80.00 805.00 0.00 520.00 256.50 606.72 145.61 145.61 14.56 

805.00 80.00 240.39 252.94 185.00 320.39 310.81 25.00 765.00 0.00 520.00 256.50 718.77 189.76 189.76 17.25 

Total 

Inflows 

14628.18 ####### 

Av.Net 

Head 

255.50 470.72 6335.63 6189.23 11.30 

78



Load 

80.66 1 

Factor 


1000 

(MW) 

Starting 

Initial 


Storage 

Level 

0 

FRL (m) . 805 


Reservoir 

0 0 

Design 


(m3/s) 



YEAR 

Head 

10% 

Loss 

Turbine 

Net storage 

discharge 

1993-1994 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

Static Head 

55.00 3 

storage 




Spill 


Level (H) 



1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 369.44 427.59 100.00 394.44 426.43 26.00 766.00 0.00 520.00 220.50 847.76 203.46 203.46 23.83 

Jun-93 766.00 26.00 511.12 591.58 102.00 537.12 430.35 80.00 805.00 98.73 520.00 221.40 859.05 206.17 206.17 24.00 

805.00 80.00 622.78 720.81 185.00 702.78 432.41 80.00 805.00 288.40 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 655.44 758.61 185.00 735.44 432.41 80.00 805.00 326.20 520.00 256.50 1000.00 240.00 228.00 24.00 

Jul-93 805.00 80.00 788.63 912.76 185.00 868.63 432.41 80.00 805.00 480.35 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1033.01 1086.92 185.00 1113.01 432.41 80.00 805.00 654.50 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 873.69 1011.22 185.00 953.69 432.41 80.00 805.00 578.81 520.00 256.50 1000.00 240.00 228.00 24.00 

Aug-93 805.00 80.00 1032.89 1195.47 185.00 1112.89 432.41 80.00 805.00 763.06 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1262.61 1328.51 185.00 1342.61 432.41 80.00 805.00 896.09 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 1045.00 1209.49 185.00 1125.00 432.41 80.00 805.00 777.07 520.00 256.50 1000.00 240.00 228.00 24.00 

Sep-93 805.00 80.00 984.36 1139.31 185.00 1064.36 432.41 80.00 805.00 706.90 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 893.92 1034.63 185.00 973.92 432.41 80.00 805.00 602.22 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 749.40 867.36 185.00 829.40 432.41 80.00 805.00 434.95 520.00 256.50 1000.00 240.00 228.00 24.00 

Oct-93 805.00 80.00 590.56 683.52 185.00 670.56 432.41 80.00 805.00 251.10 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 574.79 604.79 185.00 654.79 432.41 80.00 805.00 172.38 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 395.85 458.16 185.00 475.85 432.41 80.00 805.00 25.75 520.00 256.50 1000.00 240.00 228.00 24.00 

Nov-93 805.00 80.00 278.29 322.10 185.00 358.29 322.10 80.00 805.00 0.00 520.00 256.50 744.88 178.77 178.77 17.88 

805.00 80.00 271.03 313.69 185.00 351.03 313.69 80.00 805.00 0.00 520.00 256.50 725.45 174.11 174.11 17.41 

805.00 80.00 291.11 336.93 185.00 371.11 336.93 80.00 805.00 0.00 520.00 256.50 779.18 187.00 187.00 18.70 

Dec-93 805.00 80.00 260.32 301.29 185.00 340.32 301.29 80.00 805.00 0.00 520.00 256.50 696.77 167.22 167.22 16.72 

805.00 80.00 271.73 285.91 185.00 351.73 285.91 80.00 805.00 0.00 520.00 256.50 661.19 174.55 174.55 15.87 

805.00 80.00 226.90 262.62 185.00 306.90 262.62 80.00 805.00 0.00 520.00 256.50 607.33 145.76 145.76 14.58 

Jan-94 805.00 80.00 212.16 245.55 185.00 292.16 245.55 80.00 805.00 0.00 520.00 256.50 567.86 136.29 136.29 13.63 

805.00 80.00 216.70 228.01 185.00 296.70 228.01 80.00 805.00 0.00 520.00 256.50 527.30 139.21 139.21 12.66 

805.00 80.00 185.23 214.38 185.00 265.23 214.38 80.00 805.00 0.00 520.00 256.50 495.79 118.99 118.99 11.90 

Feb-94 805.00 80.00 191.76 221.94 185.00 271.76 221.94 80.00 805.00 0.00 520.00 256.50 513.26 123.18 123.18 12.32 

805.00 80.00 151.79 219.60 185.00 231.79 219.60 80.00 805.00 0.00 520.00 256.50 507.86 97.51 97.51 12.19 

805.00 80.00 192.13 222.37 185.00 272.13 222.37 80.00 805.00 0.00 520.00 256.50 514.25 123.42 123.42 12.34 

Mar-94 805.00 80.00 171.27 198.22 185.00 251.27 198.22 80.00 805.00 0.00 520.00 256.50 458.41 110.02 110.02 11.00 

805.00 80.00 229.09 241.05 185.00 309.09 297.87 26.00 766.00 0.00 520.00 256.50 688.85 181.86 181.86 16.53 

766.00 26.00 205.35 237.67 102.00 231.35 238.83 25.00 765.00 0.00 520.00 221.40 476.73 114.42 114.42 13.32 

Apr-94 765.00 25.00 259.38 300.21 100.00 284.38 300.21 25.00 765.00 0.00 520.00 220.50 596.82 143.24 143.24 16.78 

765.00 25.00 361.27 418.13 100.00 386.27 418.13 25.00 765.00 0.00 520.00 220.50 831.26 199.50 199.50 23.37 

765.00 25.00 446.13 516.36 100.00 471.13 429.47 80.00 805.00 23.23 520.00 220.50 853.81 204.91 204.91 24.00 

May-94 805.00 80.00 596.02 689.83 185.00 676.02 432.41 80.00 805.00 257.42 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 895.11 941.82 185.00 975.11 432.41 25.00 765.00 567.28 520.00 256.50 1000.00 264.00 250.80 24.00 

Total 

Inflows 

18296.23 ####### 

Av.Net 

Head 

250.55 458.41 7065.59 6868.79 11.00 

79



Load 

68.59 1 

Factor 


1000 

(MW) 

Starting 

Initial 


Storage 

Level 

0 

FRL (m) . 805 


Reservoir 

0 0 

Design 


(m3/s) 



YEAR 

Head 

10% 

Loss 

Turbine 

Net storage 

discharge 

2000-2001 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

Static Head 

55.00 3 

storage 




Spill 


Level (H) 



1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 468.36 542.09 100.00 493.36 429.48 80.00 805.00 48.95 520.00 220.50 853.81 204.92 204.92 24.00 

Jun-00 805.00 80.00 490.01 567.15 185.00 570.01 432.41 80.00 805.00 134.73 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 448.44 519.03 185.00 528.44 432.41 80.00 805.00 86.62 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 801.07 927.16 185.00 881.07 432.41 80.00 805.00 494.75 520.00 256.50 1000.00 240.00 228.00 24.00 

Jul-00 805.00 80.00 1000.44 1157.91 185.00 1080.44 432.41 80.00 805.00 725.50 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 805.44 847.48 185.00 885.44 432.41 80.00 805.00 415.06 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 879.55 1018.00 185.00 959.55 432.41 80.00 805.00 585.59 520.00 256.50 1000.00 240.00 228.00 24.00 

Aug-00 805.00 80.00 852.30 986.46 185.00 932.30 432.41 80.00 805.00 554.04 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 941.35 990.48 185.00 1021.35 432.41 80.00 805.00 558.07 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 935.07 1082.26 185.00 1015.07 432.41 80.00 805.00 649.84 520.00 256.50 1000.00 240.00 228.00 24.00 

Sep-00 805.00 80.00 891.22 1031.50 185.00 971.22 432.41 80.00 805.00 599.09 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 737.96 854.11 185.00 817.96 432.41 80.00 805.00 421.70 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 396.89 459.37 185.00 476.89 432.41 80.00 805.00 26.95 520.00 256.50 1000.00 240.00 228.00 24.00 

Oct-00 805.00 80.00 453.65 525.06 185.00 533.65 432.41 80.00 805.00 92.64 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 345.43 363.46 185.00 425.43 363.46 80.00 805.00 0.00 520.00 256.50 840.54 221.90 221.90 20.17 

805.00 80.00 164.27 190.13 185.00 244.27 190.13 80.00 805.00 0.00 520.00 256.50 439.69 105.53 105.53 10.55 

Nov-00 805.00 80.00 183.62 212.52 185.00 263.62 212.52 80.00 805.00 0.00 520.00 256.50 491.47 117.95 117.95 11.80 

805.00 80.00 149.88 173.47 185.00 229.88 173.47 80.00 805.00 0.00 520.00 256.50 401.16 96.28 96.28 9.63 

805.00 80.00 127.29 147.32 185.00 207.29 147.32 80.00 805.00 0.00 520.00 256.50 340.70 81.77 81.77 8.18 

Dec-00 805.00 80.00 124.63 144.24 185.00 204.63 144.24 80.00 805.00 0.00 520.00 256.50 333.58 80.06 80.06 8.01 

805.00 80.00 114.70 120.69 185.00 194.70 120.69 80.00 805.00 0.00 520.00 256.50 279.11 73.69 73.69 6.70 

805.00 80.00 92.94 107.56 185.00 172.94 107.56 80.00 805.00 0.00 520.00 256.50 248.75 59.70 59.70 5.97 

Jan-01 805.00 80.00 77.33 89.50 185.00 157.33 89.50 80.00 805.00 0.00 520.00 256.50 206.98 49.67 49.67 4.97 

805.00 80.00 97.33 102.41 185.00 177.33 102.41 80.00 805.00 0.00 520.00 256.50 236.83 62.52 62.52 5.68 

805.00 80.00 94.58 109.47 185.00 174.58 109.47 80.00 805.00 0.00 520.00 256.50 253.16 60.76 60.76 6.08 

Feb-01 805.00 80.00 75.13 86.96 185.00 155.13 86.96 80.00 805.00 0.00 520.00 256.50 201.09 48.26 48.26 4.83 

805.00 80.00 85.16 123.21 185.00 165.16 123.21 80.00 805.00 0.00 520.00 256.50 284.93 54.71 54.71 6.84 

805.00 80.00 105.85 122.51 185.00 185.85 185.01 26.00 766.00 0.00 520.00 256.50 427.86 102.69 102.69 10.27 

Mar-01 766.00 26.00 88.92 102.92 102.00 114.92 104.07 25.00 765.00 0.00 520.00 221.40 207.75 49.86 49.86 5.80 

765.00 25.00 145.91 153.53 100.00 170.91 153.53 25.00 765.00 0.00 520.00 220.50 305.22 80.58 80.58 8.58 

765.00 25.00 225.04 260.46 100.00 250.04 260.46 25.00 765.00 0.00 520.00 220.50 517.80 124.27 124.27 14.55 

Apr-01 765.00 25.00 447.48 517.91 100.00 472.48 429.47 80.00 805.00 24.78 520.00 220.50 853.81 204.91 204.91 24.00 

805.00 80.00 327.64 379.21 185.00 407.64 432.41 34.03 774.03 0.00 520.00 256.50 1000.00 240.00 228.00 24.00 

774.03 34.03 531.41 615.05 118.88 565.44 437.32 80.00 805.00 124.53 520.00 228.63 901.47 216.35 216.35 24.00 

May-01 805.00 80.00 539.29 624.18 185.00 619.29 432.41 80.00 805.00 191.77 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 664.93 699.63 185.00 744.93 432.41 25.00 765.00 325.09 520.00 256.50 1000.00 264.00 250.80 24.00 

Total 

Inflows 

14910.51 ####### 

Av.Net 

Head 

250.75 201.09 6008.38 5812.78 4.83 

80



Load 

63.13 1 

Factor 


1000 

(MW) 

Starting 

Initial 


Storage 

Level 

0 

FRL (m) . 805 


Reservoir 

0 0 

Design 


(m3/s) 



YEAR 

Head 

10% 

Loss 

Turbine 

Net storage 

discharge 

2001-2002 

Machine 

Availability 

Closing 

Reservoir 

Level 

Live 

Static Head 

55.00 3 

storage 




Spill 


Level (H) 



1 2 3 4 5 8 10 11 12 14 15 16 17 18 19 21 

765.00 25.00 791.52 916.11 100.00 816.52 429.48 80.00 805.00 422.97 520.00 220.50 853.81 204.92 204.92 24.00 

Jun-01 805.00 80.00 494.02 571.78 185.00 574.02 432.41 80.00 805.00 139.37 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1035.54 1198.54 185.00 1115.54 432.41 80.00 805.00 766.13 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 371.00 429.40 185.00 451.00 432.41 77.40 803.61 0.00 520.00 256.50 1000.00 240.00 228.00 24.00 

Jul-01 803.61 77.40 1016.05 1175.98 182.21 1093.45 434.54 80.00 805.00 738.43 520.00 255.25 1000.00 240.00 228.00 24.00 

805.00 80.00 1100.17 1157.59 185.00 1180.17 432.41 80.00 805.00 725.17 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 662.07 766.28 185.00 742.07 432.41 80.00 805.00 333.87 520.00 256.50 1000.00 240.00 228.00 24.00 

Aug-01 805.00 80.00 686.34 794.38 185.00 766.34 432.41 80.00 805.00 361.97 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 1369.23 1440.69 185.00 1449.23 432.41 80.00 805.00 1008.28 520.00 256.50 1000.00 264.00 250.80 24.00 

805.00 80.00 953.13 1103.16 185.00 1033.13 432.41 80.00 805.00 670.74 520.00 256.50 1000.00 240.00 228.00 24.00 

Sep-01 805.00 80.00 676.99 783.56 185.00 756.99 432.41 80.00 805.00 351.15 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 482.83 558.83 185.00 562.83 432.41 80.00 805.00 126.41 520.00 256.50 1000.00 240.00 228.00 24.00 

805.00 80.00 421.51 487.86 185.00 501.51 432.41 80.00 805.00 55.45 520.00 256.50 1000.00 240.00 228.00 24.00 

Oct-01 805.00 80.00 318.56 368.70 185.00 398.56 368.70 80.00 805.00 0.00 520.00 256.50 852.66 204.64 204.64 20.46 

805.00 80.00 283.96 298.78 185.00 363.96 298.78 80.00 805.00 0.00 520.00 256.50 690.97 182.42 182.42 16.58 

805.00 80.00 189.02 218.77 185.00 269.02 218.77 80.00 805.00 0.00 520.00 256.50 505.92 121.42 121.42 12.14 

Nov-01 805.00 80.00 144.13 166.82 185.00 224.13 166.82 80.00 805.00 0.00 520.00 256.50 385.79 92.59 92.59 9.26 

805.00 80.00 134.70 155.90 185.00 214.70 155.90 80.00 805.00 0.00 520.00 256.50 360.53 86.53 86.53 8.65 

805.00 80.00 90.67 104.94 185.00 170.67 104.94 80.00 805.00 0.00 520.00 256.50 242.68 58.24 58.24 5.82 

Dec-01 805.00 80.00 74.30 85.99 185.00 154.30 85.99 80.00 805.00 0.00 520.00 256.50 198.87 47.73 47.73 4.77 

805.00 80.00 76.84 80.85 185.00 156.84 80.85 80.00 805.00 0.00 520.00 256.50 186.99 49.36 49.36 4.49 

805.00 80.00 62.45 72.28 185.00 142.45 72.28 80.00 805.00 0.00 520.00 256.50 167.16 40.12 40.12 4.01 

Jan-02 805.00 80.00 62.41 72.23 185.00 142.41 72.23 80.00 805.00 0.00 520.00 256.50 167.04 40.09 40.09 4.01 

805.00 80.00 80.69 84.90 185.00 160.69 84.90 80.00 805.00 0.00 520.00 256.50 196.34 51.83 51.83 4.71 

805.00 80.00 59.60 68.98 185.00 139.60 68.98 80.00 805.00 0.00 520.00 256.50 159.53 38.29 38.29 3.83 

Feb-02 805.00 80.00 67.25 77.84 185.00 147.25 77.84 80.00 805.00 0.00 520.00 256.50 180.01 43.20 43.20 4.32 

805.00 80.00 57.28 82.87 185.00 137.28 82.87 80.00 805.00 0.00 520.00 256.50 191.65 36.80 36.80 4.60 

805.00 80.00 72.44 83.84 185.00 152.44 83.84 80.00 805.00 0.00 520.00 256.50 193.89 46.53 46.53 4.65 

Mar-02 805.00 80.00 109.00 126.16 185.00 189.00 188.66 26.00 766.00 0.00 520.00 256.50 436.30 104.71 104.71 10.47 

766.00 26.00 176.20 185.39 102.00 202.20 186.44 25.00 765.00 0.00 520.00 221.40 372.17 98.25 98.25 10.40 

765.00 25.00 132.09 152.88 100.00 157.09 152.88 25.00 765.00 0.00 520.00 220.50 303.94 72.95 72.95 8.54 

Apr-02 765.00 25.00 269.61 312.05 100.00 294.61 312.05 25.00 765.00 0.00 520.00 220.50 620.37 148.89 148.89 17.44 

765.00 25.00 560.82 649.10 100.00 585.82 429.47 80.00 805.00 155.97 520.00 220.50 853.81 204.91 204.91 24.00 

805.00 80.00 291.20 337.03 185.00 371.20 399.53 26.00 766.00 0.00 520.00 256.50 923.96 221.75 221.75 22.17 

May-02 766.00 26.00 324.68 375.79 102.00 350.68 376.95 25.00 765.00 0.00 520.00 221.40 752.44 180.58 180.58 21.02 

765.00 25.00 470.48 495.04 100.00 495.48 429.48 25.00 765.00 65.56 520.00 220.50 853.81 225.41 225.41 24.00 

Total 

Inflows 

14168.78 ####### 

Av.Net 

Head 

249.52 159.53 5530.16 5383.76 3.83 

81

CHAPTER – VIII 

POWER EVACUATION


CHAPTER - VIII 

POWER EVACUATION 



The 1000 MW Naying H.E. Project is envisaged for installation of four 

generating units of 250 MW, each operating under a rated net head of 

245.0m housed in an underground powerhouse. The generation voltage 

is proposed to be 16 KV. This voltage will be stepped up to 400KV 

voltage level by Generator step-up transformers. The Generator step-up 

transformers will be further connected to 400 KV Gas Insulated 

Switchgear (GIS) located above the transformers, both housed in the 

underground cavern. Gas Insulated Switchgear will be connected to 

outdoor potyard through 400 KV XLPE cables. The power from Naying 

H.E. Project would be fed to the North-Eastern Grid to be ultimately 

connected to the National Grid through EHV/HVDC transmission lines. 

Provision of two outgoing bays has been kept in GIS for 1000 MW power 

evacuation from this project. 

8.2 EXISTING POWER EVACUATION FACILITIES 

Power system network is controlled by the Electricity boards/ 

Departments/Corporations of the states of Assam, Meghalaya, Arunachal 

Pradesh, Nagaland, Manipur, Mizoram and Tripura. 

Power System Networks of PSUs located in the region are two 400KV 

line going to Balipara from Dikrong (Ranga Nadi) power station and two 

132KV line are also emanating from Dikrong Switchyard and feeding to 

Along and Nirjuli areas. 

82

8.3 PROPOSED POWER EVACUATION ARRANGEMENT 



It is proposed to bring the power from Naying H.E. Project to Siang Middle 

H.E. Project at 400KV voltage level. For this, one D/C outgoing 400KV 

transmission line with “Quad Moose Conductor’’ is proposed. Accordingly, 

provision for two outgoing bays has been kept at Naying H.E. Project for 

1000 MW of power evacuation. The total 2000 MW power from Siang 

Middle H.E. Project would then be further pooled at 400 KV to the pooling 

point planned near Kamki. The power from the Kamki pooling point shall 

be ultimately connected to the National Grid through EHVAC/HVDC 

transmission line. Further, it is to mention that the cost of the transmission 

network of 40 km distance from Naying H.E. Project to Siang Middle H.E. 

Project & other end equipment at Siang Middle H.E. Project have also 

been considered. 

Proposed Single Line Diagram of Switchyard is enclosed as Plate 8.1. 

83

CHAPTER – IX 

ENVIRONMENT ASPECTS


9.1.1 General 

CHAPTER- IX 

ENVIRONMENTAL ASPECTS 



Arunachal, the land of rising sun, in the extreme northeastern corner of 

India covers an area of 83740 sq.km. It lies between 26° 28’ and 29° 30’ 

north latitude and 90°30’ and 97°30’ east longitude. Mc-Mohan Line 

bounds it in the north, in the east by China and Burma ( Myanmar), in the 

south by the states of Assam & Nagaland and in the west by Bhutan. 

Most of Arunachal Pradesh is mountainous. Its terrain consists of lofty, 

haphazardly aligned ridges that separate deep valleys and rise to the 

peaks of the Great Himalayas. The state’s main rivers is Brahmaputra 

known in Ar. Pradesh as the Siang, and its tributaries, the Tirap, the 

Lohit(Zayu Qu), the Subansiri and the Bhareli. 

Naying H.E Project is located at 4 Km downstream of Yapik village on 

river Siyom in West Siang district of Arunachal Pradesh. The Siyom river 

flows towards east along a series of rapids through mountainous terrain. 

In its journey, it is joined by number of intermittent and perennial nalas. 

The Siyom flows through steep narrow V-shaped valley. The proposed 

project is a run-of-river scheme utilizing a head of about 240m in a stretch 

of about 10kms. 

9.1.2 Location 

The project area falls under survey of India (S.O.I) toposheet no 82 L/10 

is bound by 28°31'00"-28°32'10"N latitude & 94°30'18"-94°33'35"E 

longitude. The proposed dam site is located at 28º31'10" N & 94º30'25" E 

and the site is connected with a motorable road on right bank from Kaying 

to Tato and is approximately 58km from Kaying. The height of the 

84



proposed dam is 100 m from river bed level and the proposed Full 

Reservoir Level (FRL) is 805 m. The powerhouse is proposed about 6 km 

upstream of confluence of Sike with Siyom. The total area required for the 

project is approx 600 hectares. 

9.2 PHYSICAL ENVIRONMENT 

9.2.1 Climate/Meteorology 

Due to peculiar physiographic features and local influences, the climate 

has assumed a varied character in the entire Siyom valley. The climate in 

the region is fairly humid and moist. The area experiences frequent 

rainfall of varying intensity and duration. The mean annual rainfall over 

the basin as a whole has been worked out to be of the order of 269 cm 

and the mean seasonal rainfall over the basin is 218 cm (IITM, Pune). 

The average maximum annual rainfall over the basin varies from 350 cm 

to 200 cm while the mean seasonal rainfall varies from 250 cm to 150 cm. 

The maximum temperature recorded is 27.30º C and minimum (-) 8ºC at 

Ziro and the relative humidity varies from 62% to 94%. The basin 

experiences extreme cold temperatures during winter months. 

9.2.2 Topography 

The entire terrain extends over the gorgeous Eastern-Himalayan 

panorama right from the extreme southern most tip of the outer 

Himalayas siwalik formation in the south to the inaccessible Inner 

Himalayas in the North known as the Abor Hills. The entire area being 

situated in the Himalayas is covered with massive mountains with East- 

West alignment which are cut by numerous streams and rivers with the 

formation of valley in between them. The altitude of the terrain dealt with 

ranges from about 100m in the south to about 3100 m in the North. 

85

9.2.3 Soils 



The general and average soil character of cultivable land in the district is 

mainly alluvial and composed of a mixture of sand (coarse to fine) and 

clay in varying proportions. Soils in the area are results of degradation 

and weathering of rocks as well as depositional features in the form of 

river terraces. The soil on the slopes is mainly composed of silt and 

support good vegetation. The rocks exposed in the area are prone to 

weathering due to heavy rainfall and their mineral constituents. The 

clayey soils formed on river terrace due to river deposits are fertile and 

has been developed into paddy fields by the local inhabitants. 

9.2.4 Geology 

The area shows prominently one category of rock type belonging to Pari 

mountain formation of Siang group i.e. augen gneiss with a few bands of 

quartzites. The project structures viz. dam, power tunnel and the 

powerhouse will be housed in the domain of gneiss with occasional bands 

of quartzites. The gneiss shows a variation in its texture from augen to 

banded gneiss, with preferred orientation of ferro magnesium minerals.A 

detailed account of the geology of the project area has been given in 

chapter IV of this report. 

9.2.5 Seismicity 

The project area lies in the seismic zone V as per seismic zoning map of 

India as incorporated in Indian Standard, criteria for Earthquake Resistant 

Design of Structure IS: 1893(Part I); 2002:Generl provision & buildings. 

The zone is broadly associated with a seismic intensity of IX on modified 

Mercelli Scale (M.M. Scale). 

9.2.6 Catchment Area 

The catchment area of the proposed scheme lies between Longitude 

93º45′00” to 94º33′00” E and Latitude 28º25′00” to 29º 00’00” N. The 

86



catchment area upto the proposed dam site is about 2756 Sq.km. The 

Siyom river flows towards east along a series of rapids through 


and perennial nallahs. The catchment area exhibits luxuriant forest growth 

on both the banks. 

9.2.7 Drainage Pattern 

The Siyom river flows towards east along a series of rapids through 


and perennial nalas. The Siyom flows through steep narrow V-shaped 

valley. The area exhibits rugged topography having moderate to steep 

slopes. A dendritic type of drainage pattern is developed in the Siyom 

basin. 

9.2.8 Land Use Pattern 

The land use pattern of the submergence and catchment area is being 

studied using satellite data. These studies have been entrusted to NRSA, 

Hyderabad who will be using LISS-III + PAN merged satellite data and 

outcome of these studies shall be utilized in the comprehensive EIA 

report. 

9.2.9 Water Quality 

The river flows through forest areas in its entire course. Population 

density along the reservoir length is very thin. Industry or other such 

establishments are absent. The low cropping density coupled with 

negligible use of agro-chemicals means that the pollution load due to 

agrochemicals is quite low. Hence in the absence of any major 

anthropogenic and other industrial establishments in the area, it can be 

concluded that there are no major source of water pollution in the area. 

Thus water quality of the river is generally expected to be very good. 

87

9.3 BIOTIC ENVIRONMENT 

9.3.1 Vegetation 

9.3.2 Flora 



The vegetation of the valley is mostly evergreen and semi-evergreen. The 

forests are characterized by huge timber trees forming the topmost 

canopy of the forest. Apart from this, large woody climbers intermixed with 

canes are frequently spreading over the trees. Different varieties of palms 

and ferns are also observed. Wild species of bamboo and banana are 

abundant in this valley. The forest have thick under growth of shrubs 

along with herbaceous species on the forest floor. Varieties of epiphytic 

orchids, ferns, mosses and lichens are seen growing over large trees. 

The major forest types found in the project area are Tropical Evergreen 

and Tropical Semi-Evergreen. Tropical forests spread upto an elevation of 

900m above sea level. Tropical Evergreen forests are also termed as 

South Bank Tropical Wet Evergreen ( Dipterocarpus) forest and North 

Bank Tropical Evergreen (Nahar-Jutuli) forest. North Bank Tropical 

Evergreen (Nahar-Jutuli) forest occur along Semi-Evergreen forest belt 

upto an elevation of 900m. Although no single species is dominant, 

however following associations are found: Mesua-Altingia, Altingia- 

Engehardia, Altingia- Syzygium, Mesua- Syzygium. 

Tropical Semi-Evergreen forest spreads all along the forest hills and river 

bank upto an elevation of 1100m.The emergent in this type of forest are 

mainly deciduous whereas the evergreen predominant species covers 

the lower canopy. Tropical Semi-Evergreen forest can be sub-divided into 

two distinct subtypes i.e Low hills plain semi evergreen forest and 

Riverine semi-evergreen forest. The trees reported in these forests are 

Terminalia myriocarpa, Duabanga grandiflora, Bischofolia javanica, 

Bombax ceiba, Dillenia indica , Largestroemia speciosa and Albizzia sp. 

88

9.3.3 Fauna and Wildlife 



Project area has fairly good forest cover and serve as a habitat for many 

faunal species. Major faunal species reported in the area are Panthera 

tigeris ( Tiger), Panthera pardus (Leopard), Felis viverina (Fishing Cat), 

Felis chaus (Jungle Cat), Presbytes entellus (Common Langur), Macaca 

assamesis (Assamese macaque), Muntiacus muntjak (Barking deer), 

Lutra lutra (Common otter), Viverra zibetha (Large Indian civet), Bos 

frontalis (Mithun), Nonchus moschiterus (Husk deer), etc. 

Snake 

Snake species reported in the area are Python Molurus bivittatus 

(Burmese Python), Elaphes radiata (Copper head), Ptyas korras (Indo 

Chinese rat snake), Rhabdophis himalayansus (Himalayan Keelback), 

Amphiesma stolata (Striped Keelback),etc. 

Birds 

Some of the Avifauna reported in the project area:- 

1. The Great Indian Hornbill (Buceros bicorris) 

2. Himalayan wood Owl (Strix aluco) 

3. Peacock Pheasant (Polyplectroh bicalcaratum) 

4. Bared Pheasant (Crossapitilon gallus) 

5. Red Jungle Fowl (Gallus gallus) 

6. Sparrow Hawk (Accipiter nisus) 

7. Green Pigeon (Treron phoenicontera) 

8. Himalayan pied Kingfisher (Ceryle luxurbris) 

9. Jungle Crow (Corvue mecrophynachae) 

10. Small skylark (Alanda gulaula), etc. 

9.3.4 Aquatic fauna (Fisheries) 

Well-defined fish landing centers in the project area are absent. The local 

population do fishing in the nearby nallahs and river. But all these 

89



activities are only for their occasional needs. No large-scale fishing is 

practiced in the area. The fish species reported in the Siyom river are as 

under:- 

1. Tor putitora 

2. Tor tor 

3. Tor khudree 

4. Tor mussulah 

5. Tor mosal 

6. Schizothorax richardsoni 

7. Schizothorax plagiostomus 

8. Schizothorax molesworthi 

9. Eel 

10. Oxygaster bacaila 

11. Lau buka 

12. Esomus doriconus 

13. Dario rerto 

14. Rasbora doriconus 

15. Puntius saphore 

16. Puntius ticto 

9.4 SOCIO-ECONOMIC ENVIRONMENT 

9.4.1 Demography 

The total area of West Sang district is 8325 Sq.Km. with its Headquarter 

at Along. The population as per 2001 Census (Provisional) is 103575 out 

of which males are 54139 and females are 49436. Density of population 

per Sq Km is 13 and the sex ratio is 913 females per 1000 males. The 

district has the literacy rate of 60.31. The literacy rates of male and 

female are 66.72 and 53.24 respectively. 

90

Education 



To cater the educational needs of the local people, the district 

administration has constructed several schools and college in the region. 

The district has the following educational institutes: 

1. College 1 

2. Higher Sec. School 7 

3. Secondary School 16 

4. Middle School 51 

5. Primary School 168 

6. Inter village School 10 

7. Pre-primary school, Govt./ 

Non.Govt 

23 

8. R.K Mission School 1 

9. V.K.V (Secondary) 1 

10. Central School (Middle) 1 

Medical And Public Health 

The district has the following medical and public health facilities: 

1. District Hospital 1 

2. Community Health Centre 5 

3. Primary Health Centre 7 

4. Health Sub Centre 30 

5. Health Unit 1 

6. Homeo Dispensary 3 

7. Hansen Disease Sanatorium 1 

8. Sample Survey Assessment Unit ( Leprosy) 1 

9.4.2 Ethnography 

The people of Arunachal Pradesh have been generally described as 

descendants of Mongoloid, Paleo mongoloid and Proto-mongoloid race. 

91



The distinctive characteristics of the tribes in their language, dress, 

customs and food habits are direct reflection of the type of environment 

they live in geographical isolation over a long period of time. There are 

about 25 major groups with a number of sub-groups found in the state. In 

the Census report of 1961, 1971 and 1981as many as 80,110 tribes and 

105 sub-tribes were described. Census reports of 1991 and 2001 

however did not include any tribal classification. The major tribes found in 

the project area are as follows: 

a ) Adis 

i) Gallong 

ii) Minyong 

iii) Bori 

iv) Bokar 

v) Pailibo 

vi) Ramo. 

b) Membas 

The Mopin, Solung, Donging, Lossar are the main festivals of 

tribal people. 

Social structure 

The tribals of Arunachal Pradesh have organised system of functioning in 

their villages. All matters relating to the community as a whole are 

decided at the village level. The socio-administrative structure of the 

society, as evolved over a period of centuries, recognises democratic 

participation right down to the village level. Several self-governing 

institutions exist among these tribes. 

Agriculture 

Agriculture is the main occupation of the people living in and around the 

project area. Both Jhum and settled cultivation are practiced in the area. 

The climatic conditions and soil types are favourable for cultivation of 

Paddy, Maize , Millet, Chilli, Mustard, Potato and green vegetables. Jhum 

92



cultivation practiced in the region is in the form of co-operative venture in 

which the villagers do their respective work together and assist one 

another in various agricultural practices viz, clearing of forest, burning of 

jhum, sowing, weeding and reaping etc. The livestock mainly reared by 

the inhabitants are Mithun, Pig, Goat, Cattle, Poultry etc. People rear the 

animals mainly for meat, religious sacrifices, discharge of social and 

religious rituals.The main horticultural products are Orange, Pineapple, 

Pears, Banana, Guava and Plum. 

9.5 PREDICTION OF ENVIRONMENTAL IMPACTS 

The construction as well as operation activities of the project have certain 

impacts on the ecosystem, which are temporary and could last only till the 

construction activities are under progress. The repercussion of certain 

activities like road construction, tunnelling, quarrying, land clearing for 

construction of project appurtenances etc. could be serious in terms of 

environmental degradation, if the step towards restoration of the 

environment are not taken well in time. Secondly, during the operation 

phase of the project the congregation of labours and project staff may 

also pose certain threat to the water and land environment if the waste 

generated from the camps/colonies is not dumped/managed properly. 

Every possible step needs to be taken to ensure that the ecology of the 

project area is not affected. Based on above baseline data and project 

features, the potential impacts that are expected as a result of the 

proposed project are summarized as follows: 

9.5.1 Impacts on land environment 

The area coming under submergence at FRL 805 m. is about 200 ha. 

Most of the submergence area shall be falling in the gorge, therefore the 

submergence will be restricted to riverbed and no major submergence of 

the surrounding land is expected. No village or population shall come 

under submergence. The acquisition of land for various project activities 

would also lead to cutting of vegetation on these lands. With the 

93



acquisition of forest land, the local population, dependent on these 

forests, might get affected. During construction phase, activities like 

construction of roads, bridges, project colonies, quarry, excavation of 

tunnels and adits, muck generation etc may cause degradation of the 

environment, if the activities are not carried out judiciously. 

Substantial number of work force is also anticipated to congregate during 

the construction phase of the project. Solid waste and sewage generated 

from the project colonies/labour camps may pollute the land if proper 

measures for waste management are not adopted. Quarrying for 

generation of coarse and fine aggregate may leave a scar on the quarried 

land, if the land is not restored properly. Most of the environmental 

impacts, resultant of construction work, are temporary in nature rarely 

lasting beyond the construction period. 

9.5.2 Impact on Water Environment 

The construction of a reservoir replaces the river eco-system by a 

lacustrine ecosystem. The vectors of various diseases breed in shallow 

areas not very far from reservoir margins. The breeding site for 

mosquitoes and other vectors in impounded water is in direct proportion 

to the length of the shoreline. Construction of various project 

appurtenances will emanate huge quantity of debris, which if not 

meticulously disposed off, is likely to enter the river and may cause 

hindrance in the river channel downstream of the propose Dam. 

Identification of dumping sites and implementation of proper restoration 

plan for the same may be required to address the issue. The project 

would also envisage construction of temporary and permanent residential 

areas to accommodate labour and staff engaged. This may result in the 

production of domestic waste, human excreta, which if discharged into the 

river directly could affect the quality of river water. Proper waste 

management plan (solid and liquid) may therefore required to 

implemented to mitigate effect of waste on aquatic environment. 

94



Because of the regulated flow of water some changes are also likely in 

the aquatic environment in the downstream areas of the project. The 

important changes that are likely to happen in this area are: reduction in 

flow rate, changes in water temperature, reduction in population of 

stenothermal species (species adapted to small temperature range) and 

increase in population of eurythermal species (species adopted to higher 

temperature range). 

9.5.3 Impacts on Air and Noise Environment 

Impacts on the air environment is only limited to the construction period of 

a hydropower project. The major sources of air pollution during 

construction phase are emission from crushers, DG sets, construction 

equipment etc. Thus local air pollution (including dust and odour) will 

result from the operation of plant machinery and traffic. Noise and 

vibration due to construction activities (e.g. blasting, machinery and 

traffic) may disturb local wildlife and human populations. However, there 

will be only short-term increase in emissions like SO2 and Suspended 

Particulate Matter (SPM) during the construction period of the project. The 

level of noise would also decrease substantially once the construction 

phase is over. Hence no major impact is anticipated on this account. 

9.5.4 Impacts on flora and fauna 

The direct impact of construction activity of a water resources project in a 

hilly terrain is generally limited to the vicinity of the construction sites. The 

project construction would also involve substantial clearing of forest land 

etc. If the clearing activities are carried out in an unplanned manner, the 

portion of land may become devoid of vegetation resulting in the 

increased incidences of soil erosion, landslides etc. Project construction 

would also involve congregation of large labour and staff population. For 

meeting the requirement of fuel and material for construction etc. 

dependency on forest resources, which is vastly and easily available, is 

95



inevitable. The over exploitation of such resources would degrade the 

forest area to a great extent unless proper agreements for fuel supply, 

housing and furniture material is not done. Proper mitigatory measures 

during construction phase, if not taken, significant adverse impacts on 

terrestrial flora are anticipated. Mobilization of labour /construction 

machinery and other addendum activities accrued with the project 

construction like blasting, deforestation, quarrying etc. may disturb the 

wildlife habitat in the vicinity of the project. Proper conservation and 

management plans for the wildlife if required, need to be framed, to 

mitigate any adverse impacts on wildlife. 

9.5.5 Impacts on Avifauna 

The construction of the proposed dam will lead to formation of a reservoir, 

which will have a fluctuation of 5-6 m in the water level, which precisely 

means the reservoir bank will remain wet throughout the year. Due to 

such reasons, some aquatic grasses may grow along the reservoir banks. 

Such conditions are generally ideal for various kinds of birds, especially 

water birds. However because of the presence of a good habitat it is quite 

likely that water birds will flock in this area in a large number. The birds 

from cold climatic areas could also use this area during the winter season. 

9.5.6 Impacts on aquatic ecology 

The major physical change upstream of the proposed dam will be 

formation of a lacustrine habitat from a riverine habitat. Whereas below 

the dam site, there will be regulated water or very little water in river 

course. As such there will be some changes in the aquatic environment in 

this stretch. There is a possibility of stratification in the reservoir during 

winter. For this the water quality analysis shall be conducted regularly. 

Moreover, some migratory fish species may get affected due to 

construction of the dam. A detailed fishery study would be conducted 

during the EIA/EMP study to determine the likely impacts and suitable 

mitigatory measures would be adopted. 

96



9.5.7 Impacts on Socio-Economic environment 

A detailed socio-economic survey would be carried out as a part of the 

EIA/EMP study to ascertain the degree and extent of impact and 

accordingly a suitable rehabilitation package would be formulated. During 

the construction of the project the basic problem relates to management 

of large population that migrate to the area in search of jobs and other 

allied activities. Thus migration of a population having different cultural, 

ethnic and social backgrounds has its own advantages and 

disadvantages. Exchange of ideas, cultures between various groups of 

people would result in a healthy bonding amongst the population at large. 

A new culture having a distinct socio-economic status with an entity of its 

own would develop. As a result of this project there would be all-round 

development of the region. 

9.6 ENVIRONMENTAL MANAGEMENT PLANS 

The objective of the Environmental Management Plan (EMP) is to 

ameliorate the negative impacts of a developmental project. The most 

reliable way to ensure proper implementation of these management plans 

is to integrate the same with various processes involved during project 

planning, designing, construction and operation phases. Based on the 

assessment of environmental impacts, following management plans will 

be formulated: 

Catchment Area Treatment 

Compensatory Afforestation 

Biodiversity Conservation 

Resettlement and Rehabilitation 

Public Health Management System 

Muck Disposal 

Fishery Management 

Restoration of Construction Area 

Green Belt Development 

Free Fuel Provision 

Disaster Management 

The report initial environmental studies carried out by NRSA is enclosed 

as Appendix-XI. 

97

CHAPTER – X 

INFRASTRUCTURE & 

CONSTRUCTION FACILITIES


CHAPTER – X 

INFRASTRUCTURE REQUIREMENT 



Naying H.E. Project a Run of the river scheme proposed to harness hydel 

potential of Siyom river, which is a tributary of Siang river. Project 

involves construction of a Concrete Dam and underground power house 

on right bank of river. The water to power house shall be carried by 

headrace tunnels and from power house it will be carried by tail race 

tunnels in the river after generation of power. 

The Project Township and offices can be constructed at Yapik village 

located at 4 Kms U/S of Dam Site. The project site is about 251 Kms 

from Akajan (Assam), the road side town on National Highway - 52. The 

nearest important place to project site is Along the district headquarter of 

West Siang District, which is 102 Kms from it. The nearest meter Gauge 

rail head is at Silapathar (Assam) and broad gauge is at Nagaon (Assam). 

The Proposed site is 44 Kms upstream of Siang Middle project for which 

DPR has been submitted and is under TEC. 

Presently the nearest operational airport is at North Lakhimpur (Lilabari) 

in Assam state for small aircrafts. However the nearest International 

Airport is at Guwahati which is capital city of Assam. 

Inter-distances between project components/ nearby places are given as 

follows:- 

98



Distance Between TO Distance in Kms. 

• Yapik 

• Yapik 

• Yapik 

• Yapik 

• Yapik 

• Yapik 

• Yapik 

• Yapik 

Dam 

Power House 

Siang Middle HEP 

Along 

Silapathar 

Akajan 

North Lakhimpur 

Guwahati 

04 

14 

44 

102 

239 

251 

402 

802 

In order to complete the project within a period of 5 years, the project 

needs proper infrastructural development at various sites and locations to 

enable timely execution of project and also for smooth operation and 

maintenance of the project after commissioning. 

Infrastructural constructional facilities for Naying H.E. Project as 

envisaged have been divided into following components:- 

i) Road communication network. 

ii) Project Headquarter, residential / non-residential 

iii) 

complexes. 

Workshops. 

iv) Stores and Explosive Magazine. 

v) Quality control and misc. laboratory. 

vi) Diesel Powerhouse. 

vii) Fueling station. 

viii) Construction Power. 

ix) Telecommunication. 

99

10.1 Road Communication Network 



10.1.1 Improvement & utilization of National Highway & State Highway 

10.1.2 National Highway, NH-52. 

National Highway, NH-52, from Gogamukh to Akajan needs improvement 

for transportation of heavy equipment & machinery and generating plant 

and equipment of the Project. It is expected that NH-52 authorities at their 

own cost shall be carrying out this work. 

10.1.3 Approach Road from Akajan to Project site. 

The project site near village Yapik is connected by 251 Kms. long all 

weather BRTF road from Akajan. Formation width of road is 5.9 to 6.1 

mtrs. with extra widening in bends are 0.9 mtrs. Existing pavement of 

road sector is quite insufficient to sustain heavy load. Maximum 

longitudinal gradient of road is 1:12 to 1:30. The bridges on the road are 

also not sufficient to take the heavy loads. BRTF are upgrading all 

bridges to class – 24 to meet the existing load traffic. Widening/ 

improvement of this road, wherever required, strengthening of culverts 

and bridges to 70R capacity from Akajan to Dam site is required for 

movement of all heavy equipments. DPR of Siang Middle HEP has been 

submitted & is under TEC. After CCEA approval out of above 251 Kms of 

road, 207 Kms shall be strengthened & widened for Siang Middle HEP. 

Further, balance 44 Kms. shall be required to be widened and 

strengthened for Naying HEP. 

10.1.4 Project Roads 

In total 40 Kms. of road may be required to be constructed for approach 

to borrow areas, rock quarries, internal road to Dam and Power house. 

Internal road to township, approach road to work shops stores & roads for 

various adits etc. 

100

10.2 Project Headquarters, Offices and Colonies 



The construction of Naying H.E. Project is proposed to be undertaken 

through highly mechanized operations with latest construction technology 

involving minimum man power. Major construction activities involved are 

Concrete Dam. HRTs along with Intake Structures, Spillway Tunnels 

Surge Shafts, Pressure Shafts, Transformer Caverns, Power House, Draft 

Tube Gate Gallery and Tail Race Tunnels on Right Bank and diversion 

tunnel on the left bank of Siyom River. All the construction activities may 

be undertaken with fastest means to complete the project in time bound 

schedule. All the major works may be executed through the Contractors 

of international repute. Accordingly, departmental operation may remain 

restricted to Infrastructural development, overall supervision, quantity and 

quality monitoring, financial control and other construction related legal 

and safety aspects etc. 

It is proposed to construct Project head offices & quarters at Yapik which 

is 4 Km U/s of Dam site. 

The entire infrastructure may be utilized during Operation & Maintenance 

(O&M) stage of the project also. 

10.3 WORKSHOP 

10.3.1 CENTRAL WORKSHOP 

Central Workshop for heavy earth moving equipment and transport 

vehicles may be located and set up at d/s of dam site. 

The workshop may comprise facilities for the engine repairs and 

overhauling, transmission & torque convector repair shops, electrical 

shops, machine shop, OTR tyres repair shop, welding and fabrication 

shops, maintenance yard, offices and canteen etc. The workshop may be 

101



adequately fenced with control of operation through entry and exit gates. 

The main parking and maintenance yard may be created within this 

central workshop. 

10.4 STORES AND EXPLOSIVE MAGAZINE 

10.4.1 Cement, Steel and Miscellaneous Construction Materials 

The main store for cement, steel and other materials including chemicals 

may be located at Dam site near Yapik and may cater to the complete 

requirement of the entire project. Steel and other store items like bitumen 

etc., which do not require covered area would be kept outside in open. 

10.4.2 Spare Parts and Generating Unit Items 

Project will have various types of plants, equipment, vehicles etc. in 

addition to the parts of the main generating units. The storage for above 

material may be done at Dam Site near Yapik and Power house site near 

Row. 

10.4.3 Explosive Magazines 

Major project activities of Naying H.E. Project shall be confined in area of 

about 10 Sq. km where construction activities of Diversion Tunnels, Main 

Dam, Intake works, HRTs, Powerhouse, TRTs, Roads, proposed quarries 

etc. are to be carried out. For this purpose explosive magazine of a total 

capacity of 100 MT and proportionate capacity of detonators have been 

planned. Explosive magazine for the same may be constructed near 

Yapik. 

102

10.5 Quality Control & Miscellaneous Laboratory 



One quality control laboratory may be established at Dam site near Yapik. 

10.6 Diesel Powerhouse (Standby Source) 

One 5 MVA grid sub-station and 6 MW Kambang small HE Project is 

going to commissioned in 2004 in West Siang District and supply for 

residential colonies, offices & stores may be available at 33 KV level from 

Kambang sub-station. However, as a standby source one Diesel 

Powerhouse of capacity 2x500 KVA capacity at each of the location viz. 

Dam site (Yapik) and Power House (Row) may be installed for stores and 

offices. For administrative office a residential complex at Yapik 2x500KVA 

and 2x320 KVA D.G. Sets may be installed as Standby to power supply. 

10.7 Fueling Station 

One no. each fueling station for providing POL to project vehicle / 

equipment is proposed to be located at Yapik and Row. These fueling 

stations shall have storage capacity of 20 KL of Petrol and 100 KL of HSD 

due to remoteness and possibility of road closing / hill slide during rainy 

season. 

10.8 Construction Power 

The main activity of construction shall be at powerhouse, tunnels and the 

Dam area. 

The power requirement has been divided in two parts: 

1. Construction power for main works: Since there is no grid 

power available in the region and therefore total requirement for 

the construction power has to be met by the DG set. The 

estimated requirement of construction power shall be around 

6 MW. 

103



2. Power requirement for construction of infrastructure/ 

departmental works such as : 

10.9 Telecommunication 

a. Residential and non-residential buildings 

b. Departmental works 

c. Commercial complexes 

d. Street lighting 

There is no reliable telecommunication network in the region. Telephone 

exchange of BSNL at Along (the District HQ of West Siang District) is 

totally unreliable. For good communication network during construction of 

the project, Radio communication (multi channel) in addition to local 

connection from BSNL exchange are required. 

Due to frequent heavy rain in this area there are always possibility of land 

slide leading to damage of communication system. As such provision of 

wireless system may be made as a standby arrangement. 

104

CHAPTER – XI 

CONSTRUCTION 

PLANNING & SCHEDULE


CHAPTER - XI 



CONSTRUCTION PLANNING & SCHEDULE 

The equipment planning & construction methodology of Naying H.E. 

project (4x250MW) has been developed on following considerations. 

i The activities leading to CCEA clearance need about 40 

months time and schedule for these has been formulated 

(Table 11.1) 

ii The project construction period has been considered as seven 

years(Table 11.2). 

iii Available Geological Data at PFR stage. 

iv Requirement of Construction Equipment has been planned to 

handle the quantities worked out on the basis of preliminary 

layout. 

v Five months (from May to September) rainy season has been 

considered while planning surface works. The progress will 

considerably slow down during rainy season. 

11.2 CONSTRUCTION METHODOLOGY: 

11.2.1 Infrastructure Works 

The main infrastructure development is proposed to be carried out in a 

period of 12 months. During infrastructure period Land Acquisition, 

construction of approach roads, bridges & culverts, arrangement of 

construction power will be undertaken. Platform to accommodate batching 

plant, stores for construction material, site workshop, offices and other 

buildings (residential/ non residential) colonies will also be developed in 

infrastructure period. Crawler Dozer, Loader cum Excavator, Motor 

Grader, Air compressor, Road Roller etc. are proposed for deployment 

during infrastructure stage. 

105

11.2.2 Diversion of River 



The excavation of 2 Nos. 9.0m finished diameter, Horse shoe shaped 

600m long each diversion tunnel would be carried out by heading & 

benching method from 7 th month. Excavation of Diversion Tunnel will be 

carried out with 2 Boom drill jumbo, Air Track/ wagon drill, jack hammer, 

2.5Cum Side dump Loader, 25T LP dumper etc.. Excavation & concreting 

of Diversion tunnel would be completed in 17 months. The concreting 

equipment proposed are 120 cum/hr Batching & Mixing plant, Concrete 

pump, 6.0Cum Transit mixer, shotcrete m/c, Grout pump and shutters. 

U/s & D/s Coffer dam would be constructed immediately after construction 

of diversion tunnel within a period of 5 months to divert the river. 

Construction of Coffer dam would be carried out by 2.0 cum Hyd. 

Excavator, 35T Rear dumper & Crawler Dozers etc. 

11.2.3 Concrete Dam 

After construction of coffer dam and river diversion, the excavation of river 

bed will be taken up. The excavation of river bed & foundation treatment 

would be carried out in 8 months. Excavated material will be handled by 

3.0 cum Hyd. Excavator and 35t Rear dumpers. Concreting of Dam & HM 

work would be carried out in further 40 months. Concreting would be done 

by 2x20T cable ways, 2 Nos. 120 cum/hr Batching& Mixing plant and 

400TPH Aggregate Processing plant. 

11.2.4 Intake Structure 

Excavation of 2 nos. intake structure would be carried out by 1.0Cum 

Excavator and 25T Dumpers. Construction of intake structure will be 

completed in 23months including HM works. 

106

11.2.5 Head Race Tunnel 



Construction of 2Nos. 6.5 km long, 8.5 m finished diameter horse shoe 

shaped Head Race Tunnel is proposed by heading & benching method. It 

will be excavated through 3 nos adit of 6.5m dia.. The excavation of adits 

would be carried out in 6 months. Excavation of HRT would be carried out 

by 2 boom drill jumbo, Air track /wagon drill, 2.5Cum Side Dump Loader 

and 25T L.P. Dumpers. Concreting will be carried out by Concrete pump, 

Concrete shutters, 6.0cum Transit Mixer etc. The total construction period 

for the HRT will be 63months. 

11.2.6 Surge Shaft 

Construction of 2 Nos. 25m dia. Surge shaft would be taken up from top 

of surge shaft. Excavation of Surge Shaft would involve pilot hole drilling, 

reaming of pilot hole & enlargement of reamed hole. Raise borer, Wagon 

drill, Jack Hammer, L.P. Dumpers etc. will be deployed for excavation of 

Surge shaft. Concreting would be completed employing 2 m shutter. 

Construction of surge shaft would be completed in 39 months. 

11.2.7 Pressure Shaft: 

7.0 m diameter, two nos. pressure shaft will be excavated in the same 

way as surge shaft by deploying Raise borer , Jack hammer etc. Steel 

liner erection & concreting will be carried out by deploying 10/20 t 

winches, Slipform liner etc. Construction of Pressure shaft & erection of 

penstocks would take around 32 months. 

107

11.2.8 Power House 



4 X 250 MW (1000 MW) underground power house (135 m X 22 m X 44 

m size), Transformer cavern & MIV would be excavated in 20 months. 

For excavation of Power House a Main Access Tunnel would be 

excavated in about 6 months. A branch from this Main Access Tunnel 

would be extended upto the crown of power house followed by extension 

of this extended MAT upto full length of power House. Thereafter it will be 

expanded side wise to the full width of power house resulting in Power 

House Cavern. Mucking of excavated material would be done through the 

adit. From Power House Cavern 4 shafts of 2.0 m diameter would be 

excavated up to the bottom level of draft tube followed by benching of 

Power House cavern upto the bottom of Power House. Mucking will be 

carried out through TRT. The equipment to be deployed for excavation 

are jack hammers, wagon drills, air compressors, loader, excavators, 

dumpers, winches etc. Concreting of Powerhouse would be carried out 

along-with Machine erection in 30 months. Installation & Testing of 

Machine would be undertaken in such a manner that Project get 

commissioned in 84th month from the start of Project construction. 

11.2.9 Tail Race Tunnel: 

2 Nos. 500m long horse shoe shaped Tail Race Tunnel having 8.5 m 

finished diameter will be excavated by heading & benching method. 

Excavation of Tail Race Tunnel would be carried out with 2 boom Drill 

Jumbo, Wagon drill, 2.5 cum. Side Dump Loader & 20/25 t LP Dumper 

etc. The TRT will be excavated from 12 th month & will be completed in 12 

months so that TRT could be used for mucking of power house . After the 

excavation of power house the TRT will be concreted with the help of 

concrete pump, Transit mixer, Batching & mixing plant etc. 

108

S. No. 

1 Preparation of stage-I activity estimates 1 

2 

Details of works 

Data collec./ application for clearance from 

MOEF 

3 MOEF clearance 1 

4 Essent. Temp. infra./access 6 

5 Estab. of G&D sites, Metrological 

obser. And Hydrological measurement 

24 

6 Essential Geological & Geo-physical 

exploration, Topographical surveys 

7 Formulation of Feasibility Report, 

preparation of estimate for st-II activities 

14 

8 EIA / EMP studies 15 

9 Commercial viability from CEA 1 

10 Vetting & sanction of st-II activity estimates 1 

11 Detailed Topogr./Geological/Hydro 

metero. & Construction material survey 

14 

12 MOEF clearance 3 

13 Const. of resid./non resid. buildings,roads 

bridges and arrangement of const. Power 

14 Preparation of Detailed Project Report 

and its submission 

15 Techno Economic Clearance 3 

16 Pre PIB delibrations 1 

17 PIB Clearance 1 

18 CCEA Clearance (Investment Sanction) 1 

MONTHS 

Duration 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 

2 

11 

19 

14 

NATIONAL HYDROELECTRIC POWER CORPORATION LTD. 

NAYING HE PROJECT (4X250=1000 MW), SIANG BASIN, Ar. PRADESH 

Schedule for Stage-I&II activities (Upto CCEA clearanace) 

*This schedule is in accordances with three stage clearance policy of Ministry of Power ,Govt. of India vide no. 16/31/2000-DO(NHPC) dated 8/6/2001 

Table 11.1 

Contd. 

Contd. 

Zero date for 

Construction 

109(a)

Sl. 

No. 

1 INFRASTRUCTURE 

a Acquisition of private & forest land Ha 8 

b Construction of roads & buildings 

2 AWARD OF CONTRACTS 

a Tendering & awarding 

b Mobilization 

3 DIVERSION TUNNELS (2Nos. of 

600m each,9m dia) 

a 

Excavation 

3 

m 180,000 10 

b Concrete Lining 3 

m 50,000 8 

c HM Works LS Job 7 

4 COFFER DAMS (U/s & D/s) 

Const.of Coffer Dams & River Diversion m 3 

5 CONCRETE DAM 

Name of Work Unit Quantiy Duration 

LS 

LS 

LS 

445,000 

a Excavation and foundation treatment m 3 

400,000 

8 

b Mass Concreting m 3 

1017000 

36 

c Errection of Hyromechanical gates LS LS 

24 

d Reservoir filling 2 

6 POWER INTAKE (2 nos.) 

a Intake Excavation m 3 

90,000 

10 

b Concrete Lining m 3 

20,000 

8 

c HM Works Job LS 

10 

7 HEAD RACE TUNNEL (2 Nos.,6.5 km 

each) 

a Excavation of adits (3 nos.of 6.5 m D shaped) Job LS 6 

b Excavation of HRT 3 

m 130,000 40 

c Concrete Lining m 3 300,000 22 

d Grouting Job LS 12 

e Cleanning, Adit pluggings etc. Job LS 3 

f Water conductor charging Job LS 2 

8 POWER HOUSE COMPLEX 

a Const. of MAT and other Adits Job LS 6 

b Excavation of Cavern of PH, TH & MIV 

m 3 

250000 20 

c Concreting in sub & super structures 

3 

m 115,500 30 

d Erection of EOT crane Job 3 

9 SURGE SHAFT (2 Nos.,25 m dia.) 

a Excavation 3 

m 270,000 24 

b Concreting 3 

m 40,000 15 

10 PRESSURE SHAFT & PENSTOCKS 

(2 Nos.,5m dia) 


m 60,000 20 

b Concreting 3 

m 25,000 12 

11 TAILRACE TUNNEL (2 Nos.,500m 

each) 


m 170,000 12 

b Concreting & HM Works 3 

m 19,000 12 

12 SWITCHYARD Job 12 

13 ELECTRO-MECHANICAL WORKS 

a Erection, Testing & Commisioning of E&M 

components Job 48 

(months) Ist year IInd year IIIrd year 

Schedule of Constructiom 

IVth year 

V th year 

VI th year VII th year 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 

12 

3 

3 

5 

CONSTRUCTION SCHEDULE OF NAYING HE PROJECT (4X250 MW), ARUNACHAL PRADESH (Stage-III activities) 

Table 11.2 

109(b)

CHAPTER – XII 

COST ESTIMATES

CHAPTER - XII 

COST ESTIMATE 



12.0 PRELIMINARY COST ESTIMATE FOR CIVIL, HYDRO-MECHANICAL, 

ELECTRO-MECHANICAL & TRANSMISSION WORKS: - 

The estimate has been prepared to arrive at the capital cost of Naying H. 

E. Project and is of Pre-feasibility level of accuracy. The base date of the 

estimate is June 2003 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: - 

12.1.1 I-Works 

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

Project as detailed hereunder. 

12.1.2 A-Preliminary 

Under this head, provision has been made for all surveys and 

investigations to be conducted to arrive at the optimum of the project 

components. 

12.1.3 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. 

110

12.1.4 C-Works 



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

along with associated hydro-mechanical equipment. 

12.1.5 J-Power Plant Civil Works 

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

Headrace Tunnel, Power House and Transformer Cavern, Pressure 

Shaft, Surge Shaft, Tail Race Tunnel 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. A provision has been made for contingencies. 

The unit rates for various items are taken as decided by the Committee 

of CEA for preparation of PFRs. 

12.1.6 K-Buildings 

Under this head provision for both residential and non-residential have 

been provided. Under the permanent category only those structures are 

included which will be subsequently utilized during the operation and 

maintenance of the project utilities. The costs are worked out on plinth 

area basis prevalent in the area for the type of construction involved. 

12.1.7 O-Miscellaneous 

Provision under this head has been made @ 4% for C & J works for the 

Capital & running cost of Electrification, Water Supply, Sewage disposal, 

fire fighting equipments, Medical assistance, Recreation, Post Office, 

Telephone and Telegraph Office, etc. also the Provisions are made for 

111



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 their R&M charges etc. 

12.1.8 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. 

12.1.9 Q-Special Tools and Plant 

The provision of equipment has been made @ 4% of C & J Works and 

25% of this amount has been booked under this head to cover the 

residual value of equipment i.e. capital cost of the equipment less the 

credit due to resale or transfer of equipment and life of machinery used 

in works. It is assumed that 75% of the cost of the equipment is 

recovered during the execution of Project. 

12.1.10 R-Communication 

Provision under this head covers the cost of New roads, 

Widening/Improvement of roads and strengthening of bridges. The cost 

of roads and bridges are based on the prevalent rate structure prevalent 

in the area of the Project, for the type of construction involved. 

12.1.11 X-Environment and Ecology 

Provision under this head has been taken as 2.5% of C and J Works 

towards Bio-diversity Conservation, Creation of Green belt, Restoration 

of Construction Area, Catchment Area Treatment, Compensatory 

Afforestation etc 

112

12.1.12 II-Establishment 



Provision for establishment has been made at 8% of I-works minus B- 

Land for civil works. 

12.1.13 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. 

12.1.14 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. 

12.1.15 V-Receipts and Recoveries 

Under this provision, estimated recoveries by way of resale or transfer 

of equipment used in infrastructure works are provided for @ 75% of 

value booked under head Q-Special Tools and Plants. Recovery @ 15% 

of cost of temporary buildings has also been considered. 

12.1.16 Electrical & Transmission 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. 

The details of Cost Estimates are enclosed as Appendix-I. 

113

CHAPTER – XIII 

ECONOMIC EVALUATION

13.1 GENERAL 

CHAPTER - XIII 

ECONOMIC EVALUATION 



The Project has been contemplated as a run-off the river scheme on 

river Siyom. The project is estimated to cost Rs. 2630.28 crores 

excluding IDC at June 2003 Price Level. Sale price of energy 

generated at powerhouse bus bars has been worked out as 1.34 

Rs./unit. (Table 13.2) & without free power to state government comes 

to Rs. 1.18 /unit (Table 13.2-A). 

13.2 ECONOMIC JUSTIFICATION: 

The energy generation of the project with an installed capacity of 4 x 

250 MW has been estimated at 4966.76 MU in a 90% dependable 

year. 

13.3 COST ESTIMATES AND PHASING OF EXPENDITURES 

The cost of construction of the project has been estimated at June 2003 

price level with a construction schedule of 8.5 years including 1.5 years 

for Infrastructure works. 

The estimated Present Day Cost of the project is Rs. 2630.28 Crores 

without IDC at June 2003 Price level. 

13.4 PHASING OF EXPENDITURE 

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

anticipated construction programme. 

114



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

below: 

Year Estimated Cost at 

June 2003 P.L. 

(Rs. in Crores) 

1 st 

2 nd 

3 rd 

4 th 

5 th 

6 th 

7 th 

8 th 

8.5 th 

105.21 

210.42 

263.03 

315.63 

263.03 

420.85 

394.54 

368.24 

289.33 

Net Cost 2630.28 

13.5 INTEREST DURING CONSTRUCTION (IDC) 

Based upon above phasing of expenditure the interest during construction 

(IDC) have been calculated with 70:30 debt equity ratio and 10.0% 

interest on loan. (Table 13.1) 

The estimated IDC with estimated present cost is Rs. 386.67 Crores 

13.6 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. 

115



1. Debt-equity ratio 70 : 30 

2. Annual interest rate on loan 10.0% 

3. Return on equity 16% 

4. Annual interest rate on working capital 10.0% 

5. O&M Charges 1.5% of Project Cost 

6. Free power to Home State 12% of the energy 

available after losses 

7. Depreciation considered 1/12 th of loan amount 

during loan repayment 

period. 

The levellised tariff of the Project at present day cost works out to be Rs. 

1.09 per unit. (Table 13.3) & tariff without free power to state government 

comes to Rs. 0.96 per unit (Table 13.3-A). 

116

Table-13.1 

STATEMENT SHOWING IDC CALCULATION AT PRESENT DAY COST (APRIL 2003 LEVEL) 

PRESENT DAY COST 2630.28 Crs. Transmission Work 99.96 Crores 

Civil Works 1726.99 Crs. Electrical Works 803.34 Crs. 

INTEREST RATE PER ANNUM 10% Transmission cost 99.96 Crs. 

(Rs. in Crs.) 

Present Day Amount Receivable I.D.C Loan Outstanding Amount Receivable 

Year Cost Equity Loan at the end of Equity Loan 

year 

(for the year) 

1 2 3 4 5 6 7 8 

1 105.21 105.21 105.21 

2 210.42 210.42 210.42 

3 263.03 263.03 263.03 

4 315.63 315.63 315.63 

5 263.03 10.79 252.24 12.09 264.33 10.79 264.33 

6 420.85 420.85 47.48 732.65 468.32 

7 394.54 394.54 92.99 1220.19 487.54 

8 368.24 368.24 140.43 1728.86 508.67 

8.5 289.33 289.33 93.68 2111.87 383.01 

Total 2630.28 905.09 1725.20 386.67 905.09 2111.87 

IDC 386.67 Crs. Equity 905.09 Crs. 

Net cost of the project 3016.95 Crs. Loan 2111.87 Crs. 

117

TABLE-13.2 

UNIT COST OF ENERGY AT BUS BAR AT CURRENT PRICE LEVEL 

(June 2003 P.L.) 

(Based on 16% return on equity & 10% interest on loan, 10% interest on working capital) 

1 Installed capacity 1000 MW 

2 Cost of the Project (Net) Rs. 2630.28 Crores 

3 Interest During Construction Rs. 386.67 Crores 

4 Total Cost of Project Rs. 3016.95 Crores 

(Including IDC) 

a) Equity 30% Rs. 905.09 Crores 

b) Loan 70% Rs. 2111.87 Crores 

5 Annual Energy Generation 4966.76 MU 

6 0.7% As Auxiliary Consumption of No. 5 0.70% 34.77 MU 

7 Energy Available After Auxiliary Consumption 4931.99 MU 

8 0.5% As Transformer Loss of No. 7 0.50% 24.66 MU 

9 Energy Available After Transformer Loss 4907.33 MU 

10 Free Power to Home State 12% 588.88 MU 

11 Energy Available After Allowing Free Power 4318.45 MU 

12 Fixed and Running Charges 

A) Capacity Charges 

a) Interest on Loan 10.00% 202.39 Crores 

b) Depreciation Charges 175.99 Crores 

(Limited to 1/12 th of Loan Amount) 

SUB-TOTAL 378.38 Crores 

B) Energy Charges 

a) O&M Charges 1.50% 45.25 Crores 

b) Return on Equity 16.00% 144.81 Crores 


c) Interest on Working Capital 10.00% 10.02 Crores 

I) O&M Charges for 1 month 3.77 

II) 2 Months Average Billing 96.41 

TOTAL Rs. 578.46 Crores 

13 Sale Price at Bus Bar/Unit 1.34 Rs. 

14 Cost of Generation at Bus Bar/Unit 0.88 Rs. 

(Without Allowing Free Power to Home State and Return on Equity) 

Note : This unit rate is excluding water cess, income tax incentive, penalties etc. 

118

TABLE-13.2 -A 


(June 2003 P.L.) 


































118 (A)

NAYING H. E. PROJECT, ARUNACHAL PRADESH (4 X 250 MW) 

CALCULATION OF ENERGY RATE WITH PRESENT COST (JUNE 2003 PRICE LEVEL) AS PER TARIFF NOTIFICATION 

TABLE-13.3 

Annual Generation in a 90% dependable year 4966.76 MU O&M Charges 1.50% 

Annual Generation after allowing losses & free Rate of increase of O&M Charges after 1st Year (simple) 6% 

power to home state in a 90% dependable year 4318.45 MU Interest rate on Loan 10.0% 

Total cost including IDC Rs. 3016.95 Crores Interest rate on Working Capital 10.00% 

Equity 30% Rs. 905.09 Crores Return on Equity 16% 

Loan 70% Rs. 2111.87 Crores Discounting rate 12% 

YEAR CAPACITY CHARGES CHARGES PER UNIT Discounting Discounted 

Out- (Rs.in Cr.) (Rs.in Cr.) 

(Rs. per Unit) Factor Tariff 

standing Interest Depre- Total Return O&M Interest on Working Capital Total Capacity Energy Total (Paisa per 

Loan on loan ciation on equity Charges O&M for 2 months Interest charges charges Unit) 

(Rs.in Cr.) 1 month Average 

Billing 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 

1 2111.87 202.39 175.99 378.38 144.81 45.25 3.77 96.41 10.02 200.09 0.88 0.46 1.34 1.0000 1.34 

2 1935.88 184.79 175.99 360.78 144.81 47.97 4.00 93.89 9.79 202.57 0.84 0.47 1.30 0.8929 1.16 

3 1759.89 167.19 175.99 343.18 144.81 50.85 4.24 91.40 9.56 205.23 0.79 0.48 1.27 0.7972 1.01 

4 1583.90 149.59 175.99 325.58 144.81 53.90 4.49 88.94 9.34 208.06 0.75 0.48 1.24 0.7118 0.88 

5 1407.91 131.99 175.99 307.98 144.81 57.13 4.76 86.51 9.13 211.07 0.71 0.49 1.20 0.6355 0.76 

6 1231.92 114.39 175.99 290.38 144.81 60.56 5.05 84.11 8.92 214.29 0.67 0.50 1.17 0.5674 0.66 

7 1055.93 96.79 175.99 272.78 144.81 64.19 5.35 81.75 8.71 217.72 0.63 0.50 1.14 0.5066 0.58 

8 879.95 79.20 175.99 255.18 144.81 68.05 5.67 79.43 8.51 221.37 0.59 0.51 1.10 0.4523 0.50 

9 703.96 61.60 175.99 237.59 144.81 72.13 6.01 77.14 8.32 225.26 0.55 0.52 1.07 0.4039 0.43 

10 527.97 44.00 175.99 219.99 144.81 76.46 6.37 74.90 8.13 229.40 0.51 0.53 1.04 0.3606 0.38 

11 351.98 26.40 175.99 202.39 144.81 81.04 6.75 72.70 7.95 233.80 0.47 0.54 1.01 0.3220 0.33 

12 175.99 8.80 175.99 184.79 144.81 85.91 7.16 70.55 7.77 238.49 0.43 0.55 0.98 0.2875 0.28 

13 0.00 0.00 26.23 26.23 144.81 91.06 7.59 44.55 5.21 241.09 0.06 0.56 0.62 0.2567 0.16 

14 0.00 26.23 26.23 144.81 96.52 8.04 45.49 5.35 246.69 0.06 0.57 0.63 0.2292 0.14 

15 26.23 26.23 144.81 102.32 8.53 46.48 5.50 252.63 0.06 0.59 0.65 0.2046 0.13 

16 26.23 26.23 144.81 108.45 9.04 47.53 5.66 258.92 0.06 0.60 0.66 0.1827 0.12 

17 26.23 26.23 144.81 114.96 9.58 48.64 5.82 265.60 0.06 0.62 0.68 0.1631 0.11 

18 26.23 26.23 144.81 121.86 10.15 49.82 6.00 272.67 0.06 0.63 0.69 0.1456 0.10 

19 26.23 26.23 144.81 129.17 10.76 51.07 6.18 280.17 0.06 0.65 0.71 0.1300 0.09 

20 26.23 26.23 144.81 136.92 11.41 52.39 6.38 288.12 0.06 0.67 0.73 0.1161 0.08 

21 26.23 26.23 144.81 145.14 12.09 53.80 6.59 296.54 0.06 0.69 0.75 0.1037 0.08 

22 26.23 26.23 144.81 153.84 12.82 55.28 6.81 305.47 0.06 0.71 0.77 0.0926 0.07 

23 26.23 26.23 144.81 163.08 13.59 56.86 7.05 314.93 0.06 0.73 0.79 0.0826 0.07 

24 26.23 26.23 144.81 172.86 14.41 58.53 7.29 324.97 0.06 0.75 0.81 0.0738 0.06 

25 26.23 26.23 144.81 183.23 15.27 60.31 7.56 335.60 0.06 0.78 0.84 0.0659 0.06 

26 26.23 26.23 144.81 194.23 16.19 62.19 7.84 346.88 0.06 0.80 0.86 0.0588 0.05 

27 26.23 26.23 144.81 205.88 17.16 64.18 8.13 358.83 0.06 0.83 0.89 0.0525 0.05 

28 26.23 26.23 144.81 218.23 18.19 66.29 8.45 371.49 0.06 0.86 0.92 0.0469 0.04 

29 26.23 26.23 144.81 231.33 19.28 68.53 8.78 384.92 0.06 0.89 0.95 0.0419 0.04 

30 26.23 26.23 144.81 245.21 20.43 70.90 9.13 399.15 0.06 0.92 0.99 0.0374 0.04 

31 26.23 26.23 144.81 259.92 21.66 73.41 9.51 414.24 0.06 0.96 1.02 0.0334 0.03 

32 26.23 26.23 144.81 275.51 22.96 76.08 9.90 430.23 0.06 1.00 1.06 0.0298 0.03 

33 26.23 26.23 144.81 292.04 24.34 78.90 10.32 447.18 0.06 1.04 1.10 0.0266 0.03 

34 26.23 26.23 144.81 309.57 25.80 81.90 10.77 465.15 0.06 1.08 1.14 0.0238 0.03 

35 26.23 26.23 144.81 328.14 27.35 85.07 11.24 484.20 0.06 1.12 1.18 0.0212 0.03 

TOTAL 9.1566 9.95 

(A) (B) 

Note: The charges per unit is exclusive of water cess, spares, incentive & Income Tax etc. Levellised Tariff =(B)/(A) 1.09 

119



TABLE-13.3-A 


Annual Generation after allowing losses Rate of increase of O&M Charges after 1st Year (simple) 6% 

in a 90% dependable year 4907.33 MU Interest rate on Loan 10.0% 










Billing 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 

1 2111.87 202.39 175.99 378.38 144.81 45.25 3.77 96.41 10.02 200.09 0.77 0.41 1.18 1.0000 1.18 

2 1935.88 184.79 175.99 360.78 144.81 47.97 4.00 93.89 9.79 202.57 0.74 0.41 1.15 0.8929 1.02 

3 1759.89 167.19 175.99 343.18 144.81 50.85 4.24 91.40 9.56 205.23 0.70 0.42 1.12 0.7972 0.89 

4 1583.90 149.59 175.99 325.58 144.81 53.90 4.49 88.94 9.34 208.06 0.66 0.42 1.09 0.7118 0.77 

5 1407.91 131.99 175.99 307.98 144.81 57.13 4.76 86.51 9.13 211.07 0.63 0.43 1.06 0.6355 0.67 

6 1231.92 114.39 175.99 290.38 144.81 60.56 5.05 84.11 8.92 214.29 0.59 0.44 1.03 0.5674 0.58 

7 1055.93 96.79 175.99 272.78 144.81 64.19 5.35 81.75 8.71 217.72 0.56 0.44 1.00 0.5066 0.51 

8 879.95 79.20 175.99 255.18 144.81 68.05 5.67 79.43 8.51 221.37 0.52 0.45 0.97 0.4523 0.44 

9 703.96 61.60 175.99 237.59 144.81 72.13 6.01 77.14 8.32 225.26 0.48 0.46 0.94 0.4039 0.38 

10 527.97 44.00 175.99 219.99 144.81 76.46 6.37 74.90 8.13 229.40 0.45 0.47 0.92 0.3606 0.33 

11 351.98 26.40 175.99 202.39 144.81 81.04 6.75 72.70 7.95 233.80 0.41 0.48 0.89 0.3220 0.29 

12 175.99 8.80 175.99 184.79 144.81 85.91 7.16 70.55 7.77 238.49 0.38 0.49 0.86 0.2875 0.25 

13 0.00 0.00 26.23 26.23 144.81 91.06 7.59 44.55 5.21 241.09 0.05 0.49 0.54 0.2567 0.14 

14 0.00 0.00 26.23 26.23 144.81 96.52 8.04 45.49 5.35 246.69 0.05 0.50 0.56 0.2292 0.13 

15 0.00 0.00 26.23 26.23 144.81 102.32 8.53 46.48 5.50 252.63 0.05 0.51 0.57 0.2046 0.12 

16 0.00 0.00 26.23 26.23 144.81 108.45 9.04 47.53 5.66 258.92 0.05 0.53 0.58 0.1827 0.11 

17 0.00 0.00 26.23 26.23 144.81 114.96 9.58 48.64 5.82 265.60 0.05 0.54 0.59 0.1631 0.10 

18 0.00 0.00 26.23 26.23 144.81 121.86 10.15 49.82 6.00 272.67 0.05 0.56 0.61 0.1456 0.09 

19 0.00 0.00 26.23 26.23 144.81 129.17 10.76 51.07 6.18 280.17 0.05 0.57 0.62 0.1300 0.08 

20 0.00 0.00 26.23 26.23 144.81 136.92 11.41 52.39 6.38 288.12 0.05 0.59 0.64 0.1161 0.07 

21 0.00 0.00 26.23 26.23 144.81 145.14 12.09 53.80 6.59 296.54 0.05 0.60 0.66 0.1037 0.07 

22 0.00 0.00 26.23 26.23 144.81 153.84 12.82 55.28 6.81 305.47 0.05 0.62 0.68 0.0926 0.06 

23 0.00 0.00 26.23 26.23 144.81 163.08 13.59 56.86 7.05 314.93 0.05 0.64 0.70 0.0826 0.06 

24 0.00 0.00 26.23 26.23 144.81 172.86 14.41 58.53 7.29 324.97 0.05 0.66 0.72 0.0738 0.05 

25 0.00 0.00 26.23 26.23 144.81 183.23 15.27 60.31 7.56 335.60 0.05 0.68 0.74 0.0659 0.05 

26 0.00 0.00 26.23 26.23 144.81 194.23 16.19 62.19 7.84 346.88 0.05 0.71 0.76 0.0588 0.04 

27 0.00 0.00 26.23 26.23 144.81 205.88 17.16 64.18 8.13 358.83 0.05 0.73 0.78 0.0525 0.04 

28 0.00 0.00 26.23 26.23 144.81 218.23 18.19 66.29 8.45 371.49 0.05 0.76 0.81 0.0469 0.04 

29 0.00 0.00 26.23 26.23 144.81 231.33 19.28 68.53 8.78 384.92 0.05 0.78 0.84 0.0419 0.04 

30 0.00 0.00 26.23 26.23 144.81 245.21 20.43 70.90 9.13 399.15 0.05 0.81 0.87 0.0374 0.03 

31 0.00 0.00 26.23 26.23 144.81 259.92 21.66 73.41 9.51 414.24 0.05 0.84 0.90 0.0334 0.03 

32 0.00 0.00 26.23 26.23 144.81 275.51 22.96 76.08 9.90 430.23 0.05 0.88 0.93 0.0298 0.03 

33 0.00 0.00 26.23 26.23 144.81 292.04 24.34 78.90 10.32 447.18 0.05 0.91 0.96 0.0266 0.03 

34 0.00 0.00 26.23 26.23 144.81 309.57 25.80 81.90 10.77 465.15 0.05 0.95 1.00 0.0238 0.02 

35 0.00 0.00 26.23 26.23 144.81 328.14 27.35 85.07 11.24 484.20 0.05 0.99 1.04 0.0212 0.02 

TOTAL 9.1566 8.76 

(A) (B) 


119(A)

APPENDIX – I 

Preliminary Cost Estimates


S.No 

ABSTRACT OF COST OF WORKS 

Description Amount 

(Rs. in Crores) 

( June 2003 

A CIVIL WORKS 

1. DIRECT CHARGES 

I - Works 

A - Preliminary 11.46 

B - Land 21.38 

C - Works 523.98 

J - Power Plant Civil Works 725.60 

K - Buildings 48.26 

O - Miscellaneous 62.61 

P - Maintenance 14.11 

Q-Special Tools & Plants 9.96 

R - Communication 113.00 

X - Environment & Ecology 31.30 

Y - Losses on Stock 3.53 

Total of I-Works 1565.18 

II - Establishment @ 8% of cost of I-Works less B-Land 123.50 

III - Tools and Plants @ 1% of cost of I-Works 15.65 

IV - Suspense 0.00 

V - Receipt & Recoveries (-) 6.63 

TOTAL DIRECT CHARGES 1710.97 

2. INDIRECT CHARGES 

a) Capitalised Value of Abatement of Land Revenue 0.37 

b) Audit and Account Charges @1% of cost of I-Works 15.65 

TOTAL INDIRECT CHARGES 16.02 

TOTAL OF DIRECT & INDIRECT CHARGES 1726.99 

ABSTRACT : 

A Civil Works 1726.99 

B Electrical Works 803.34 

C Transmission Works 99.96 

TOTAL COST 2630.28 

C IDC 386.67 

D Total Cost With IDC 3016.95

Sl.No 

. 

NAYING H.E. PROJECT, ARUNACHAL PRADESH(500 MW) 

A-Preliminary 

Proposed detailed survey for final location 

Details Unit Qty Rate 

(in Lacs) 

Amount 

(in Lacs) 

A Expenditure for preparation of PFR 14.00 

B (i) Topographical survey: Dam, Power 

House & water conductor system 

LS 200.00 

ii) Reservoir survey LS 40.00 

iii) Cross-section, Long section of 

river/nallahs etc. 

LS 40.00 

Total 294.00 

C Geological/ Geophysical/ Geotechnical survey 

i Drilling M 900 0.10 90.00 

ii Drifting M 350 0.12 42.00 

iii Geophysical Km 5 4.00 20.00 

iv Resistivity survey Km 6 5.00 30.00 

v Tomography LS 30.00 

vi Rock Mechanics Test LS 50.00 

vii Ground Water studies 10.00 

viii Satellite Imageries & aerial Photographs 20.00 

Total 292.00 

D Construction Material Survey and testing L.S. 50.00 

E IMD Observation L.S. 10.00 

F Helicopter Support Hrs 100.00 

G EIA/EMP L.S. 50.00 

H Documentation & Computer charges L.S. 25.00 

I Expert/TAC L.S. 50.00 

J Model Studies L.S. 200.00 

K Training of Engineers L.S. 30.00 

L Welfare measure L.S. 25.00 

M Library books/software L.S. 20.00 

Total 560.00 

Grand Total 1146.00

S. 

No. 

Name of Project Component Quantity Unit Rate in 

Rs. 

Amount 

(Rs. In 

Lakhs) 

1. Land Requirement 

Private Land with Forest cover 600.0 Ha. 2.47 1482.00 

Total Charges for Land Acquisition 1482.00 

2 Cost of Establishment for land acquisition 

@ 6.25% 

92.63 

3 Solatium charges @ 30% of the cost of 

444.60 

Private Land 

4 Interest charges on amount of award for 

the period between taking over possession 

of land and date of award @ 12% per 

annum on 25% of cost of total 

compensation for 2 years 

88.92 

5 Legal charges @ 1% of total compensation 14.82 

6 Labour and material required for 

measurement & demarcation of 

land/Properties @ 1% of cost of land 

Acquisition 

B - LAND 

Grand Total 

14.82 

2137.79

S. N. Description 

ABSTRACT OF COST OF C - WORKS 

Amount (Rs. In Lakhs) 

CIVIL HM TOTAL 

1. DIVERSION TUNNEL 5015.52 267.75 5283.27 

2. DAM & COFFER DAMS 40488.08 3290.28 43778.36 

TOTAL 45503.60 3558.03 49061.63 

ADD FOR WORKS TAX @ 6.8% 3094.24 241.95 3336.19 

GRAND TOTAL 48597.84 3799.98 52397.82

S. No.Description 

DIVERSION TUNNEL 

Unit Qty. Rate Amount 

( Rs. in 

Lakhs) 

1 Surface Excavation 

1.1 Common excavation Cum 50000 125 62.5 

1.2 Rock excavation Cum 10000 300 30 

2 Underground excavation Cum 120000 1000 1200 

3 Support System 

3.1 Rock bolts M 80000 400 320 

3.2 Steel Rib Supports MT 500 42000 210 

3.3 Shotcrete Cum 5000 4000 200 

4 Concrete 

4.1 PCC Lining and plug M-25 Cum 25000 4500 1125 

4.2 Concrete in overbreak M-25 Cum 15000 3610 541.5 

4.3 R.C.C. M-25 Cum 10000 3610 361 

5 Reinforcing steel MT 1000 27000 270 

Sub total A 4320.00 

6 

Miscellaneous and ancillary works 

@7.5% of sub-total A 

7.50% 324.00 

Sub total B 4644.00 

7 Instrumentation @ 1% of sub-total B 1.00% 46.44 

8 Dewatering @ 2% of sub total B 2.00% 92.88 

9 

Contingency @ 3% of sub-total B 

(except on L.S. items) 

3.00% 139.32 

10 

Work Charged establishment @ 2% of 

Sub-total B except of lum-sum items 

2.00% 92.88 

Total civil works 5015.52

DAM & COFFER DAMS 

S. No. Description Unit Quantity Rate Amount 

( Rs. in 

Lakhs) 


1.1 Common excavation Cum 200000 125 250 


2 Rock Stabilization and Supports 

2.1 Rock bolts/anchor/dowels 25 mm m 10000 400 40 

2.2 Shotcrete Cum 2000 4000 80 

3 Embankment Constrcution and Backfill 

3.1 Compacted Clay Cum 20000 354 70.8 

3.2 Rock fill Cum 400000 518 2072 

3.3 Filter Cum 20000 901 180.2 

3.4 Rip-Rap Cum 5000 781 39.05 

4 Concrete including Formwork 

4.1 Mass concrete, M-15 Cum 800000 2930 23440 

4.2 RCC M-25 Cum 210000 3610 7581 

4.3 High performance concrete Cum 5000 3800 190 

4.4 M-30 Cum 2000 3800 76 


Sub Total(A) 36239.05 

6 

Miscellaneous and Ancillary 

Works @2.5% of sub-total A 2.5% 905.98 

Sub-Total(B) 37145.03 

7 Instrumentation @ 1% of sub-total (B) 1% 371.45 

8 Dewatering @ 3% of sub total (B) 3% 1114.35 

9 Contingency @ 3% of sub-total 

except on L.S. items 3% 1114.35 

10 Work Charged establishment @ 

2% of Sub-total (B) except of 

lum-sum items 2% 742.90 


J -POWER PLANT APPURTENANCES (CIVIL WORKS) 

S. Description 

Amount (Rs. in Lakhs) 

NO. CIVIL HM TOTAL 

1 ADITS & M.A.T. 2809.03 3.47 2812.50 

2 POWER INTAKE (2 Nos.), HEAD RACE 

TUNNEL (2 Nos.) AND GATE SHAFTS 

34698.81 990.15 35688.96 

3 TAIL RACE TUNNELS (2 Nos.) 2630.13 42.00 2672.13 

4 PRESSURE SHAFT, SURGE SHAFTS AND 

PENSTOCK 

8283.75 5088.83 13372.58 

5 POWER HOUSE COMPLEX 12206.94 312.48 12519.42 

6 CIVIL WORKS FOR SWITCH YARD 874.39 874.39 

Total 61503.05 6436.92 67939.97 

ADD FOR WORKS TAX @ 6.8% 4182.21 437.71 4619.92 

GRAND TOTAL 65685.26 6874.63 72559.89

S. 

No. 

Description Unit Qty. Rate Amount 

( Rs. in 

Lakhs) 

1 Surface Excavation at Portals 

1.1 Common excavation m 3 

1.2 Rock excavation m 3 

2 Underground excavation m 3 

20000 125 25 

5000 300 15 

100000 1000 1000 

3 Rock stabilisation and supports 

3.1 Rockbolts/Rock 25 mm dia m 65000 400 260 

3.2 Structural steel Rib MT 350 42000 147 

3.3 Shotcrete m 3 

3000 4000 120 

4 Concrete 

ADITS & M.A.T. 

4.1 PCC Lining and plug M25 m 3 

4.2 Concrete in overbreaks M-25 m 3 

4.3 R.C.C. M25 m 3 

10000 4500 450 

5000 3610.00 180.5 

5000 3610.00 180.5 


Sub Total(A) 2513 

6 

Miscellaneous and ancillary 

works @3.5% of sub-total A 3.5% 87.96 


7 Instrumentation @ 1% of sub-total (B) 1% 26.01 

8 Dewatering @ 2% of sub total (B) 2% 52.02 

9 

Contingency @ 3% of sub-total 

(B) 

Work Charged establishment @ 

3% 78.03 

10 2% of Sub-total except of lumsum 

items 2% 52.02 

Total Civil Cost 2809.03

S. No. Description Unit Qty. Rate Amount 

( Rs. in 

Lakhs) 

1 Surface excavation 



2 Underground excavation m 3 

40000 125 50.00 

50000 300 150.00 

1250000 1000 12500.00 

3 Rock stabilisation and supports 

3.1 Rock bolts m 400000 400 1600.00 

3.2 Steel Rib Supports MT 6000 42000 2520.00 

3.3 Shotcreting m 3 

25000 4000 1000.00 

4 Concrete 

4.1 PCC Lining and plug M25 m 3 

4.2 Concrete in overbreaks M25 m 3 

4.3 RCC M25 m 3 

200000 4500 9000.00 

50000 3610 1805.00 

20000 3610 722.00 

5 Reinforcing Steel MT 2000 27000 540.00 


6 


works @7.5% of sub-total 7.5% 2241.53 

Sub Total(B) 32128.53 

7 Instrumentation @ 1% of sub-total B 1% 321.29 

8 Dewatering @ 2% of sub total B 2% 642.57 

9 

Contingency @ 3% of sub- 

10 

POWER INTAKE (2 Nos.), HEAD RACE TUNNEL (2 Nos.) AND GATE SHAFTS 

total B except on L.S. items 3% 963.86 

Work Charged establishment 

@ 2% of Sub-total B except 

of lum-sum items 2% 642.57 


TAIL RACE TUNNELS (2 Nos.) 


( Rs. in 

Lakhs) 


1.1 Common excavation Cum 50000 125 62.5 


2 Underground excavation Cum 95000 1000 950 


3.1 Rockbolts m 20000 400 80 

3.2 Steel Rib Supports MT 200 42000 84 

3.3 Shotcrete Cum 2600 4000 104 

4 Concrete 

4.1 PCC Lining and plug M25 Cum 10000 4500 450 

4.2 Concrete in overbreaks M25 Cum 4000 3610 144.4 

4.3 R.C.C. M25 Cum 5000 3610 180.5 

5 Reinforcing Steel MT 500 27000 135 

6 


@7.5% of sub-total A 

Sub-Total(A) 

7.5% 

2265.40 

169.91 




9 Contingency @ 3% of sub-total B 

Work Charged establishment @ 

3% 73.06 

10 2% of Sub-total B except of lumsum 

items 2% 48.71 


PRESSURE SHAFT, SURGE SHAFTS AND PENSTOCK 


( Rs. in 

Lakhs) 




100000 125 125.00 

50000 300 150.00 

2 Underground excavation 

2.1 

Surge Shaft, Pressure Shaft 

and Penstock m³ 200000 1000 2000.00 


3.1 Rock bolts / anchors 25mm dia m 150000 400 600.00 

3.2 Structural steel Rib MT 100 42000 42.00 

3.3 Shotcrete m³ 10000 4000 400.00 

4 Concrete 

4.1 R.C.C. Lining M25/A40 m 3 

4.2 Backfill concrete M20 m 3 

40000 4500 1800.00 

40000 3390 1356.00 



6 


works @2.5% (sub-total) 2.5% 188.83 




9 

Contingency @ 3% of subtotal 

B 


3% 232.25 

10 @ 2% of Sub-total B except 




( Rs. in 

Lakhs) 

1 Under ground excavation m 3 

250000 1000 2500.00 

2 Rock stabilization and Supports including accessories 

2.1 Rockbolts m 175000 400 700.00 

2.3 Steel ribs support MT 500 42000 210.00 


8000 4000 320.00 

3 Concrete including formwork 

3.1 PCC Lining M25 m 3 

3.2 Concrete in overbreak M25 m 3 

3.3 R.C.C. M25 m 3 

3.4 Blockout concrete M30 m 3 

25000 4500 1125.00 

10000 3610 361.00 

90000 3610 3249.00 

500 3800 19.00 


5 Structural Steel for roof trusses etc. MT 100 42000 42.00 

6 Masonry Work 

6.1 Brick Masonry m 3 

7 

20000 2000 400.00 



@4.5% of sub-total A 4.5% 486.72 




10 Contingency @ 3% of sub-total B 3% 339.08 

11 

POWER HOUSE COMPLEX 

Work Charged establishment @ 2% of 

Sub-total B except of lum-sum items 2% 226.05 


S. No. Description Unit Qty. Rate Amoun 

t ( Rs. 

in 

Lakhs) 




50000 125 62.50 

10000 300 30.00 

2 Rock Stabilization and Supports 

2.1 Rock bolts - 25 mm diameter m 2000 400 8.00 


100 4000 4.00 

3 Earthwork in filling and Back m 3 

4 Concrete including formwork 

4.1 M15 m 3 

4.2 M25 m 3 

50000 342 171.00 

4000 2930 117.20 

3000 3610 108.30 


6 Stone / Brick Masonry m 3 

10000 2000 200.00 


6 


works @4.5% of sub-total A 4.5% 35.19 



9 Contingency @ 3% of sub-total B 3% 24.52 

10 

CIVIL WORKS FOR SWITCH YARD 


@ 2% of Sub-total B except 



Sl. 

No. 

K-BUILDINGS 

Description of Building Unit Total 

Plinth 

Area 

Rate 

(In Rs.) 

Amount 

(Rs. In 

Lacs) 

1 Residential Buildings 

(i) C/o Permanent buildings Sqm 26920 7,000 1884.40 

(ii) Service charges @ 31% 584.16 

Total residential buildings 2468.56 

2 Non- residential Buildings 

(i) C/o Permanent buildings Sqm 23400 6,100 1427.40 

(ii) Service charges @ 22.5% 321.17 

(i) C/o Temporary buildings Sqm 10100 5,000 505.00 

(ii) Service charges @ 20.5% 103.53 

Total Non-residential Buildings 2357.09 

Grand Total (Residential + Non-residential) 

4825.65

R - Communication 

Sl. No. Description Unit Qty Rate 

(in 

Lacs) 

Amt 

(Lacs) 

1 Approach Road to borrow 

areas/ quarries 

KM 35 40 1400 

2 Approach Road to disposal 

areas 

KM 10 40 400 

3 Approach to power 

house/dam/DT HRT etc 

KM 20 70 1400 

4 Approach road to 

workshop/store 

KM 5 70 350 

5 Approach road to explosive 

magazine 

KM 5 50 250 

6 Internal Road in township KM 8 50 400 

7 Widening/strengthening of 

roads/bridges 

KM 60 100 6000 

8 New road from tuting to project 

site 

KM 10 70 700 

9 Permanent bridge 100m span no 1 350 350 

10 Construction of Helipad no 1 50 50 

Total: 11300

HYDROMECHANICAL WORKS 

S No TYPE OF GATE NOS./ TOTAL WT Rate/t 

SETS MT 

1 DIVERSION TUNNEL GATE 

a FIXED WHEEL GATE 4 120 60000 72.00 

b EMBEDDED PARTS 4 30 50000 15.00 

c ROPE DRUM HOIST CAPACITY 4 120 100000 120.00 

d HOIST STRUCTURE 4 96 50000 48.00 

2 UPPER SPILLWAY CREST GATES 

a RADIAL GATE 4 520 100000 520.00 

b RADIAL GATE EMBEDDED PARTS INCL. 

SUPPORTING STRUCTURE FOR HYDRAULIC 

CYLINDERS 

4 280 50000 140.00 

c HYDRAULIC HOIST 300 T (2x 150 T FOR 

EACH GATE) 

4 L.S 13000000 520.00 

d POWER PACKS 4 L.S 2500000 100.00 

e PORTABLE POWER PACK 1 L.S 2000000 20.00 

f STOP LOGS 1 115 60000 69.00 

g STOP LOGS EMBEDDED PARTS 4 120 50000 60.00 

I LIFTING BEAM 1 6 60000 3.60 

j STOPLOG STORAGE GROOVE & COVER 1 10 50000 5.00 

3 LOWER SPILLWAY ORIFICE GATES 

a RADIAL GATE 5 500 100000 500.00 

b RADIAL GATE EMBEDDED PARTS INCL. 

SUPPORTING STRUCTURE FOR HYDRAULIC 

CYLINDERS 

5 300 50000 150.00 

c HYDRAULIC HOIST 300 T (2X150 T FOR EACH 

GATE) 

5 L.S 8500000 425.00 

d POWER PACKS 5 L.S 2500000 125.00 

e PORTABLE POWER PACKS 1 L.S 2000000 20.00 

f BULKHEAD GATE 1 110 60000 66.00 

g BULKHEAD GATE E.PARTS INCL. GROOVE 

LINERS 

5 175 50000 87.50 

h GANTRY CRANE 150 T 1 L.S 15000000 150.00 

i LIFTING BEAM 1 10 75000 7.50 

j BULKHEAD STORAGE GROOVE & COVER 1 10 50000 5.00 

k BREAST WALL LINER (HIGH STRENGTH 

STEEL) 

5 50 70000 35.00 

4 INTAKE GATE 


b FIXED WHEEL GATE EMBEDDED PARTS 2 80 50000 40.00 

c ROPE DRUM HOIST CAPACITY 240 T 2 170 100000 170.00 

d HOIST SUPPORTING STRUCTURE 2 140 50000 70.00 

a BULKHEAD GATE 2 210 60000 126.00 

b BULKHEAD GATE EMBEDDED PARTS 2 60 50000 30.00 

c ROPE DRUM HOIST CAPACITY 160 T 2 110 100000 110.00 


5 TRASH RACKS / TRASH RACK CLEANING MACHINE 

Total cost 

(in Lacs)

S No TYPE OF GATE NOS./ TOTAL WT Rate/t Total cost 

a TRASH RACKS 2 150 50000 75.00 

b TRASH RACKS EMBEDDED PARTS 2 60 50000 30.00 

c TRASH RACKS CLEANING MACHINE 1 T 

CAPACITY 

1 10000000 100.00 

6 ADIT GATES 

ADIT GATES 3 30 60000 1.80 

EMBEDDED PARTS 3 18 50000 1.50 

7 SURGE SHAFT GATE 

a SLIDE GATE 2 90 60000 54.00 


c ROPE DRUM HOIST 65 T CAPACITY 2 50 100000 50.00 


8 DRAFT TUBE GATE 



c ROPE DRUM HOIST 35T CAPACITY 8 120 100000 120.00 

d HOIST STRUCTURE 8 80 50000 40.00 

9 TRT STOPLOG 

a STOPLOG 1 45 60000 27.00 


c LIFTING BEAM 1 5 60000 3.00 

10 PRESSURE SHAFT LINER 

a FERRULES (ASTM A537 CL. 1) 2 2450 70000 1715.00 

b FERRULES (ASTM A517 GR. F) 2 4000 70000 2800.00 

c BIFURCATION (ASTM A517 GR. F) 2 250 77000 192.50 

11 ARMAC & COMPUTER CONTROL & 

INSTRUMENTATION 

1 L.S 10000000 100.00 

12 DG SET (500KVA) 1 2500000 25.00 

13 CONTINGENCIES @ 5% FOR SPARES, AIR 

VENTS, BY PASS ARRANGEMENT ETC. 

Sub Total 9519.00 

5% 475.95 

Total 9994.95

Q-Spl T&P for Infrastructure Development 

Sl. No. Description of equipment Quantity 

(Nos.) 

Rate 

(Rs in 

Lacs) 

Amount 

(Rs in 

Lacs) 

1 Hydraulic Excavator, 1.0 cum. 4 45.00 180.00 

2 Loader cum Excavator, 1.0/0.25 

cum. 

2 20.00 40.00 

3 Crawler Dozer, 200 FHP with 

ripper 

4 85.00 340.00 

4 Crawler Dozer, 100 FHP 3 50.00 150.00 

5 Wheel Dozer, 200 FHP 2 80.00 160.00 

6 Multi Utility Loader 2 40.00 80.00 

7 Motor Grader, 145 FHP 2 60.00 120.00 

8 Diamond Core Drill (Mechanical) 4 15.00 60.00 

9 Diamond Core Drill (Hyd) 2 60.00 120.00 

10 Rock splitter 4 10.00 40.00 

11 Hyd. Rock breaker 2 60.00 120.00 

12 Front end loader 1.5 -2.0 cum 2 30 60 

13 Air Track/Wagon Drill 6 16.00 96.00 

14 Jack Hammer/Pavement 40 0.25 10.00 

15 Compressed Air(cfm) 10000 0.0125 125.00 

16 Mobile Crane, 10 t Pick & Carry 2 10.00 20.00 

17 Mobile Crane, 20 t (Rough 

terrain) 

2 70.00 140.00 

18 Mobile crane 40t (R/T) 1 90.00 90.00 

20 Road Roller, 8/10 t 2 10.00 20.00 

21 Concrete Mixer, 14/10 cft 2 2.00 4.00 

22 Dewatering Pump L.S 20.00 20.00 

23 Tipper 4.5/6.0 cum. 20 10.00 200.00 

24 Truck, 10 t 10 8.00 80.00 

25 Low Bed Tractor Trailor, 30 t 2 50.00 100.00 

27 Motor boat 6 5.00 30.00 

28 Barges with trawlers 6 10.00 60.00 

29 Motorised winch 100 HP 4 5.00 20.00 

30 Motorised winch 200 HP 2 10.00 20.00 

31 Explosive Van, 10 t 2 12.00 24.00 

32 Water Tanker/Sprinkler, 10 KL 4 15.00 60.00 

33 Petrol/Diesel Tanker, 10 KL 4 12.00 48.00 

34 Bus/Mini Bus 8 10.00 80.00 

35 Car/MUV 6 5.50 33.00 

36 Jeep (Petrol/Diesel) 30 4.50 135.00 

37 Ambulance 4 10.00 40.00 

38 Workshop Equipment L.S 20.00 20.00 

39 Fire Tender 2 15.00 30.00 

40 Recovery Van 1 5.00 5.00 

41 Pick up Van/L.C.V 10 5.00 50.00 

Total 3030.00

DISTRIBUTION OF COST UNDER HEAD Q - SPECIAL T & P AND V - 

RECEIPT & RECOVERIES 

Cost of equipments excluding inspection 

vehicles 

Cost of inspection vehicles (Item 24 to 27 

Provision under head Q - Spl. T&P 

Recoveries to be shown under V- Receipt 

and Recoveries 

Cost Q R&R 

(Rs. In 

lakhs) 

2712.00 678 508.50 

318.00 318.00 63.60 

3030.00 996.00 

572.10

V - RECEIPT & RECOVERIES 

S. No. Item Amount 

(Rs. In Lakhs) 

1. Recovery from the Sale of Equipments 572.10 

2 Recovery from temporary Buildings 91.28 

23 

Total 663.38

COST ESTIMATE OF NAYING H.E. PROJECT ( 4 X 250 MW) 

Electro Mechanical Works 

Generator, Turbine and Accessories 

S.No. Item Particulars Qty Rate Amount Excise Duty* 

Total 

(Rs Lcs) Rate Amount (Rs Lcs) 

1 

A 

2 3 4 5 6 7 5+7 

1 

(a) Generating units and Bus Ducts 4 X 250 MW, 214.3 

rpm, Head 245 meters 

4 

3600.00 

Rs/KW 

36000.00 16 5760.00 41760.00 

2 Step up transformer 16/400/√3 KV, 102 MVA 13 

250.00 

Rs/KVA 

3315.00 16 530.40 3845.40 

3 

Auxiliary Electrical Equipment for Power Stations, (Except 

Transformer) (5% of item 1) 

1800 16 288 2088 

4 

Auxiliary Equipment & Services for Power stations, (5% of 

Item 1) 

1800 16 288 2088 

5 Spares (5% of 1, 3% of 2-4) 2007.45 16 321.19 2328.64 

6 SUB TOTAL (A1) 52110.04 

7 Central Sales tax **4% of item 6 2084.40 

8 Transportation & Insurance 6% of basic cost(Item 1 - 5) 2695.35 

9 Erection & commissioning 8% of item 6 except spares 3982.51 

10 SUB TOTAL (A2) 60872.30 

11 

Establishment,Contingency,other charges , 11% of item 1- 

5 Except duties 

4941.47 

12 

B 

SUB TOTAL (A) 65813.77 

13 GIS (400KV) 

7 

bays 

600 

lacs/bay 

4200.00 22 

Custom duty 

924.00 5124.00 

14 XLPE Cable 400 kV with cable termination kit 2.8 400000 515.2 22 113.344 628.54 

km US$/km Custom duty 

15 Switchyard Spares ( 2% of item 13 and item 14) 94.30 22 

Custom duty 

20.75 115.05 

16 Subtotal(B1) 1058.09 5867.59 

17 Transportation & Insurance 3% of basic cost(item 13-15) 144.29 


19 Subtotal(B2) 

Establishment,Contingency,other charges , 8% of item 13- 

6472.08 

20 15 except duties + 2% handling charge on custom duties of 

item 13-15 

405.92 

21 SUB TOTAL (B) 6878.01 

GRAND TOTAL (A+B) (In Lacs) 

*Custom duty in case of imported Items 

**Not applicable for Imported Items 

72691.78 

Annexure-I

COST ESTIMATE OF NAYING H.E. PROJECT ( 4 X 250 MW) 

Electro Mechanical Works 

Power Evacuation Cost 

Annexure-II 

S.No. Item Particulars Qty Rate Amount Excise Duty* Total 

(Rs Lcs) Rate Amount (Rs Lcs) 

1 2 3 4 5 6 7 5+7 

1 

400 KV GIS at receiving end 

2 600 1200 16 192.00 1392.00 

bays lacs/bay 

2 Double circuit Transmission line with quad moose 

40 90 3600 16 576.00 4176.00 

conductor (400 KV, 40km) 

Km. Lacs/km 

3 XLPE Cable 400 kV with cable termination kit 2.8 400000 515.2 22 113.344 628.54 

km US$/km Custom duty 

4 Switchyard Spares [ 2% of item 1, 2 & 3] 106.30 16 17.01 123.31 

5 Subtotal(1) 6319.86 

6 Central Sales tax **4% of item 1,2 & 4 227.65 

7 Transportation & Insurance 3% of basic cost(item 1-4) 162.65 


9 Subtotal(2) 

Establishment,Contingency,other charges , 8% of item 

7205.88 

10 1-4 except duties + 2% handling charge on custom 

duties of item 3 

435.99 

GRAND TOTAL (In Lacs) 

*Custom duty in case of imported Items 

**Not applicable for Imported Items 

7641.86

Table-13.1 

STATEMENT SHOWING IDC CALCULATION AT PRESENT DAY COST (APRIL 2003 LEVEL) 

PRESENT DAY COST 2630.28 Crs. Transmission Work 99.96 Crores 

Civil Works 1726.99 Crs. Electrical Works 803.34 Crs. 

INTEREST RATE PER ANNUM 10% Transmission cost 99.96 Crs. 

(Rs. in Crs.) 

Present Day Amount Receivable I.D.C Loan Outstanding Amount Receivable 

Year Cost Equity Loan at the end of Equity Loan 

year 

(for the year) 

1 2 3 4 5 6 7 8 

1 105.21 105.21 105.21 

2 210.42 210.42 210.42 

3 263.03 263.03 263.03 

4 315.63 315.63 315.63 

5 263.03 10.79 252.24 12.09 264.33 10.79 264.33 

6 420.85 420.85 47.48 732.65 468.32 

7 394.54 394.54 92.99 1220.19 487.54 

8 368.24 368.24 140.43 1728.86 508.67 

8.5 289.33 289.33 93.68 2111.87 383.01 

Total 2630.28 905.09 1725.20 386.67 905.09 2111.87 

IDC 386.67 Crs. Equity 905.09 Crs. 

Net cost of the project 3016.95 Crs. Loan 2111.87 Crs. 

117

TABLE-13.2 


(June 2003 P.L.) 


































118



TABLE-13.3 


Annual Generation after allowing losses & free Rate of increase of O&M Charges after 1st Year (simple) 6% 

power to home state in a 90% dependable year 4318.45 MU Interest rate on Loan 10.0% 










Billing 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 

1 2111.87 202.39 175.99 378.38 144.81 45.25 3.77 96.41 10.02 200.09 0.88 0.46 1.34 1.0000 1.34 

2 1935.88 184.79 175.99 360.78 144.81 47.97 4.00 93.89 9.79 202.57 0.84 0.47 1.30 0.8929 1.16 

3 1759.89 167.19 175.99 343.18 144.81 50.85 4.24 91.40 9.56 205.23 0.79 0.48 1.27 0.7972 1.01 

4 1583.90 149.59 175.99 325.58 144.81 53.90 4.49 88.94 9.34 208.06 0.75 0.48 1.24 0.7118 0.88 

5 1407.91 131.99 175.99 307.98 144.81 57.13 4.76 86.51 9.13 211.07 0.71 0.49 1.20 0.6355 0.76 

6 1231.92 114.39 175.99 290.38 144.81 60.56 5.05 84.11 8.92 214.29 0.67 0.50 1.17 0.5674 0.66 

7 1055.93 96.79 175.99 272.78 144.81 64.19 5.35 81.75 8.71 217.72 0.63 0.50 1.14 0.5066 0.58 

8 879.95 79.20 175.99 255.18 144.81 68.05 5.67 79.43 8.51 221.37 0.59 0.51 1.10 0.4523 0.50 

9 703.96 61.60 175.99 237.59 144.81 72.13 6.01 77.14 8.32 225.26 0.55 0.52 1.07 0.4039 0.43 

10 527.97 44.00 175.99 219.99 144.81 76.46 6.37 74.90 8.13 229.40 0.51 0.53 1.04 0.3606 0.38 

11 351.98 26.40 175.99 202.39 144.81 81.04 6.75 72.70 7.95 233.80 0.47 0.54 1.01 0.3220 0.33 

12 175.99 8.80 175.99 184.79 144.81 85.91 7.16 70.55 7.77 238.49 0.43 0.55 0.98 0.2875 0.28 

13 0.00 0.00 26.23 26.23 144.81 91.06 7.59 44.55 5.21 241.09 0.06 0.56 0.62 0.2567 0.16 

14 0.00 26.23 26.23 144.81 96.52 8.04 45.49 5.35 246.69 0.06 0.57 0.63 0.2292 0.14 

15 26.23 26.23 144.81 102.32 8.53 46.48 5.50 252.63 0.06 0.59 0.65 0.2046 0.13 

16 26.23 26.23 144.81 108.45 9.04 47.53 5.66 258.92 0.06 0.60 0.66 0.1827 0.12 

17 26.23 26.23 144.81 114.96 9.58 48.64 5.82 265.60 0.06 0.62 0.68 0.1631 0.11 

18 26.23 26.23 144.81 121.86 10.15 49.82 6.00 272.67 0.06 0.63 0.69 0.1456 0.10 

19 26.23 26.23 144.81 129.17 10.76 51.07 6.18 280.17 0.06 0.65 0.71 0.1300 0.09 

20 26.23 26.23 144.81 136.92 11.41 52.39 6.38 288.12 0.06 0.67 0.73 0.1161 0.08 

21 26.23 26.23 144.81 145.14 12.09 53.80 6.59 296.54 0.06 0.69 0.75 0.1037 0.08 

22 26.23 26.23 144.81 153.84 12.82 55.28 6.81 305.47 0.06 0.71 0.77 0.0926 0.07 

23 26.23 26.23 144.81 163.08 13.59 56.86 7.05 314.93 0.06 0.73 0.79 0.0826 0.07 

24 26.23 26.23 144.81 172.86 14.41 58.53 7.29 324.97 0.06 0.75 0.81 0.0738 0.06 

25 26.23 26.23 144.81 183.23 15.27 60.31 7.56 335.60 0.06 0.78 0.84 0.0659 0.06 

26 26.23 26.23 144.81 194.23 16.19 62.19 7.84 346.88 0.06 0.80 0.86 0.0588 0.05 

27 26.23 26.23 144.81 205.88 17.16 64.18 8.13 358.83 0.06 0.83 0.89 0.0525 0.05 

28 26.23 26.23 144.81 218.23 18.19 66.29 8.45 371.49 0.06 0.86 0.92 0.0469 0.04 

29 26.23 26.23 144.81 231.33 19.28 68.53 8.78 384.92 0.06 0.89 0.95 0.0419 0.04 

30 26.23 26.23 144.81 245.21 20.43 70.90 9.13 399.15 0.06 0.92 0.99 0.0374 0.04 

31 26.23 26.23 144.81 259.92 21.66 73.41 9.51 414.24 0.06 0.96 1.02 0.0334 0.03 

32 26.23 26.23 144.81 275.51 22.96 76.08 9.90 430.23 0.06 1.00 1.06 0.0298 0.03 

33 26.23 26.23 144.81 292.04 24.34 78.90 10.32 447.18 0.06 1.04 1.10 0.0266 0.03 

34 26.23 26.23 144.81 309.57 25.80 81.90 10.77 465.15 0.06 1.08 1.14 0.0238 0.03 

35 26.23 26.23 144.81 328.14 27.35 85.07 11.24 484.20 0.06 1.12 1.18 0.0212 0.03 

TOTAL 9.1566 9.95 

(A) (B) 


119

APPENDIX – II 

Drawings

APPENDIX – III 

Ranking Study by CEA.

NAYING HYDRO ELECTRIC SCHEME 

(Drawing No. HEPR-PS-BHM-772) 

APPENDIX - III 

The Siyom river offers yet another possibility for hydro electric development 

downstream of the Tato-II scheme where the river falls through a head of about 

240 m. in a stretch of about 10 kms. A run-of-river scheme utilising this head, 

about 6 kms. upstream of confluence of Sike with Siyom would give benefit of 

about 131 MW of firm power with an annual energy generation of 2480 GWH 

and 2780 GWH respectively in 90% and 50% dependable years. The scheme 

would involve a diversion structure of small height on the river at a site where 

the river bed level is +710 m., a channel about 9 km. Long and a power house 

with a tailrace level of +470 m. The optimum generation capacity may be about 

500 MW.

APPENDIX – IV 

Conceptual Planning approval by 

CEA.

APPENDIX – V 

Report of Geological Survey of India

APPENDIX – VI 

Comments of CEA vide 7/9(NHPC)/2003/HP&I/1044 

dated 07.10.03 & U.O. No. 82/18/2003-SP&PA/ dated 

23.10.2003 & Reply of NHPC

Reply to the comments of SP&PA Division , CEA issued vide U.O. 

No. 82/18/2003-SP&PA/ dated 23.10.2003 

Naying HE Project -1000 MW (4x250 MW) 

Sl. 

COMMENTS of CEA REPLY of NHPC 

No. 

i) Naying HE Project conceived by CEA across It is a statement. 

Siyom river (a tributary of Siang river is one of 

the 43 schemes entrusted to NHPC by CEA for 

preparation of PFR under Prime Minister's 

50,000 MW initiative. 

ii) Location 

Naying HE Project, a run-of-river scheme has It is a statement. 

been proposed to harness hydel potential of 

Siyom river and is located 40 kms. up stream of 

Siang Middle dam site and 4 kms. down stream 

of village Yapik which is around 102 kms. from 

Along district HQ of West Siang District and 802 

kms. from Guwahati. The Naying HE Project is 

one of the four schemes identified on the river 

Siyom. The other three schemes in the vicinity 

of Naying HE Project are Hirong HEP, Tato-ll 

HEP and Siang Middle HEP. Siang Middle HEP 

lies down stream of Naying HEP while Tato-ll 

and Hirong HEP lie up stream of Naying HEP. 

iii) Cost of the project 

The project is estimated to cost Rs. 3280 crores Estimated cost & 

including IDC of Rs. 381 crores at October 2003 levalised tariff are Rs. 

PL. The levelised tariff works out to be 98 paise 2949.84 crores & Rs. 

per unit. 

1.03 per unit respectively 

in final PFR. 

iv) Power House 

Naying power house is located 30 kms. up It is a statement. 

stream of Siang Middle HEP and 10 kills. down 

stream of Naying dam site. Naying HE Project 

which would be an underground power house 

envisages installation of 4 units of 250 MW 

each. Power is proposed to be generated at 16 

kV and stepped up to 400 kV through 13 nos. 

102 MY A 16/400 kV single phase generator 

step up transformers as stated under para 7.0 

of chapter 7. The generator step up 

transformers would be further connected to 400 

kV GIS located above the transformers. This is 

in order.

v) Power Evacuation 

In order to evacuate 1000 MW from Naying 

HEP, a 400 kV D/C line 60 kms. in length with 

Quad Moose conductor from Naying HEP to 

400 kV Pooling S/s being planned near Siang 

Middle HEP bas been proposed as stated under 

para 8.2 of chapter 8. Accordingly two 400 kV 

outgoing line bays have been kept in the Naying 

HEP switchyard. This is in order. Power from 

this pooling point would be ultimately connected 

to National Grid through EHVAC/HVDC 

transmission lines. Single line diagram of the 

switchyard may be furnished. 

vi) Construction Power 

There is no grid power available near the 

project. Construction power of the order of 6 

MW for the project would be met by DG sets. 

vii) Cost of transmission works 

It has been stated under para 8.2 of chapter 8 

that the cost of 400 kV D/C transmission line 

from Naying HEP to Siang Middle pooling point 

and other end equipments at Siang Middle 

pooling point has been included in the cost of 

this project. The cost of electrical works 

including transmission works has been given as 

Rs. 852.01 crores under the abstract of cost of 

works of Appendix-I. The details of cost of 

transmission works have not been furnished, in 

the absence of which we have no comments to 

otter. The details of these works may, be 

furnished. 

viii) GENERAL COMMENTS 

(a) It may be stated that the benefits from these 

projects may not be fully absorbed from NE 

Region and needs to be exported to other 

regions. In long term perspective for evacuating 

bulk power from we may need to adopt a 

combination of HVDC/EHVAC transmission 

system which requires least transmission 

corridor, because of limited corridor in the 

chicken-neck area taking into account the 

various power projects likely to be developed in 

NER in foreseeable future. We may need to 

plan an integrated transmission system from the 

pooling points in NER and phase out the 

implementation schedule suitably. 

Single line diagram of 

the switchyard have 

been furnished as Plate 

8.1 in the final PFR. 

It is a statement. 

Details of cost of 

transmission work of Rs. 

76.42 crores has been 

separately enclosed in 

Appendix-I in the final 

PFR. 

A pooling point at Kamki 

has been proposed for 

Siyom basin projects. An 

integrated transmission 

system from pooling 

point in NER would be 

plant in consultation with 

CEA/PGCIL in due 

course.

(b) The transmission system as proposed for above 

schemes is tentative. The final transmission 

system would be determined by detailed power 

system studies on the basis of total power to be 

transmitted from NER, which may require a 

change in the voltage levels or configuration of 

the transmission I system taking into 

consideration the mountainous terrain. thick 

forest area and right of way problems. 

(c) Beneficiaries States/Regions along with their 

tentative shares from these projects have not 

been identified so far, nor the time frame of the 

projects has been given. 

A- GENERAL COMMENTS 

1. An Executive Summary may also be 

incorporated in the PFR as per format given at 

Annex -IV. 

2. It may be ensured that the Initial Environmental 

studies incorporated in the PFR are as per 

scope of work for PFR. 

3. The Financial Parameters may be taken as per 

guidelines sent vide our Lr. No. 7/9/HPI- 

2003/1118-1123, dated 21st October, 2003. 

4. The Cost Estimates may be prepared taking 

into account the Guidelines sent vide our Lr. 

No. 7/9/HP&I/2003/1163-1172, dated 

24.10.2003. 

5. NHPC may indicate recommendations for 

further studies required wherever necessary in 

the relevant chapters of PFRs for consideration 

during Feasibility Report/DPR stage. 

6. It is presumed that geological inputs of the area 

are as per information supplied by GSI. The 

report of GSI may also be included in the PFR. 

7. It may be ensured that the Installed Capacities 

& assessment of power benefits takes into 

account various comments and advise given in 

this regard. 

8. It may be ensured that the water availability 

adopted for power potential studies is approved 

by CWC. 

The final transmission 

system would be 

determined by detailed 

power system studies at 

the time of preparation of 

DPR etc. in due course. 

This issue would be 

addressed appropriately 

during preparation of 

DPR. 

Executive summary as 

per the prescribed format 

has been incorporated in 

the final PFR. 

Initial Environmental 

studies have been 

carried out by NRSA 

which has been 

enclosed in final PFR. 

Guidelines have been 

followed in final PFR. 

Cost estimates have 

been prepared as per 

the guidelines 

Recommendation for 

further studies have 

been incorporated in the 

relevant chapter of final 

PFR. 

The report of GSI has 

been included in final 

PFR. 

Comments of the various 

agency have been taken 

into consideration. 

The water availability 

adopted for power 

potential studies has 

been vetted by CWC & 

their comments and

9. The power evacuation arrangements 

considered in the PFR should take into account 

views and suggestions of SP&PA Division of 

CEA. 

B- POWER POTENTIAL STUDIES 

viii. It may be ensured that all our previous 

comments sent vide letter dated 09.10.2003 are 

taken into account. 

reply of NHPC have 

been appended in the 

final PFR. 

For power evacuation 

arrangement views and 

suggestion of SP&PA 

division has been 

considered while 

preparing of final PFR. 

All previous comments 

have been taken into 

account for power 

potential studies.

APPENDIX – VII 

Comments of CWC on Hydrology vide 

Letter No. 4/330/2003 HYD NE/341 

Dt. 28-10-2003 & Reply of NHPC

Annexure-II 

REPLY OF CWC OBSERVATIONS RECEIVED VIDE LETTER NO.4/330/2003 HYD 

Data 

availability 

NE/341 DT. 28-10-2003 

CWC Observations Reply of NHPC 

(i) Though the project authorities has 

stated about the availability of data, the 

same has not been furnished in the 

report. The data may be incorporated on 

10-daily/monthly basis. Efforts may be 

made to obtain site specific data from 

other agencies also. 

(ii) A detailed contour map of Siang basin 

to the scale of 1:2,50,000 showing all the 

details like sub basin boundaries, rainfall 

stations, discharge observation sites, 

existing/ongoing projects etc. may be 

furnished. 

(iii) A complete list of all rainfall stations, 

Discharge sites along with 10-daily 

rainfall and discharge data of the sites 

under the project catchment may be 

incorporated in the report. 

The rainfall data at Mechuka, Monigong and 

Raying, as mentioned in data status has 

been given to explain the rain gauge network 

in the basin. However, since this rainfall data 

was not used in the analysis, the same has 

not been furnished in the report. If required 

by CWC, the data may be presented. Kindly 

refer Annexure-II, Hydrology Volume 

(Volume-III) of DPR of Siang Middle H.E 

project, for the average 10-daily water 

availability series, which has been converted 

to Naying site. 

Lot of efforts has been made to collect all 

available data in the basin, and all rainfall 

and discharge data collected and available 

has been given in the data status. Efforts are 

still being made to collect more data and the 

same will be used during feasibility and DPR 

stage. 

(ii) The information required by CWC cannot 

be given due to unavailability of toposheets 

of 1:2,50,000 scale, covering catchment area 

of Siang basin. However, a basin map of 

Siyom river, showing all the 

hydrometeorological stations as well as 

existing and ongoing projects is enclosed as 

Annexure-I. 

(iii) The list of rainfall and discharge stations 

lying upto the catchment of Siang Middle H.E 

project has already been shown in the data 

availability status given in report. However, if 

required by CWC, the data volume showing 

the rainfall and discharge data may be 

presented.

Consisten 

cy of data 

Water 

availability 

studies 

It is stated that the basis of water 

availability studies of this project is the 

10-daily series developed at Middle 

Siang dam site. But the project 

authorities has not mentioned anything 

about the internal and external 

consistency checks performed for 

concurrent period rainfall and runoff data 

of Pangin G&D site, which is the basis for 

the series developed at Middle Siang 

dam site. The same is required to be 

incorporated in the report. 

(i) In the report the project authorities has 

mentioned that the stations located to the 

south east of Siang Middle Basin i.e 

Passighat and Denning recorded heavy 

rainfall where as rainfall slowly 

decreases towards Siang Middle basin. 

The proposed project is located about 

100 km u/s of Pangin site and in the light 

of above statement it is not justified to 

use the catchment area proportion only 

for converting the discharge series. In 

event of unreliable observed data, the 

average catchment rainfall ratio in 

addition to the catchment area ratio may 

be applied to derive the yield series only 

for the purpose of PFR. 

(ii) In the report it is mentioned that 

NHPC itself has established a G&D site 

u/s of Middle Siang dam. However, data 

G&D data at Pangin G&D site was available 

for the period 1978-1994. For this period, no 

concurrent rainfall data was available in 

Siyom basin to perform rainfall-runoff 

analysis. Even at Mechuka rain gauge 

station, data for the period 1974 to 1996 was 

missing. So rainfall-runoff analysis could not 

be performed. However, regression analysis 

has been done between 17 months 

concurrent data (Jan 02 to May 03) at Pangin 

G&D site and Middle Siang dam site (being 

observed by NHPC) and the linear 

regression developed seems to be well fit. 

Catchment area proportion has only been 

used for converting the discharge series at 

Siang Middle dam site to proposed Naying 

project. No rainfall data for concurrent period 

was available in the basin of proposed 

project for obtaining catchment rainfall ratio. 

For Siang Middle H.E project, located about 

72km upstream of Pangin G&D site, water 

availability series has been obtained on the 

basis of regression equation developed 

between observed discharges at Middle 

Siang dam site and Pangin G&D site for 

concurrent period (Jan 02 to May 03). The 

linear regression equation thus developed is: 

QD = 0.712QP - 1.8487 -----------------(1) 

R 2 = 0.95 

Where, 

QD = Measured Discharges at Middle Siang 

Dam site 

QP = Measured Discharge at Pangin G&D 

site 

The above equation is then used for 

converting Pangin discharges to proposed 

dam site of Middle Siang. 

(ii) It is true that NHPC has established a 

G&D site 600 m upstream of proposed dam 

axis Middle Siang. Data at this site is

Design 

Flood 

of the same has not been analysed and 

utilized in the present report. Use of data 

of site u/s of Middle Siang dam would be 

more reliable than the Pangin site which 

is located about 100 km d/s of the 

proposed site. Runoff-rainfall factor may 

be evaluated on the observed data after 

applying consistency checks and 

correlation established for comparison 

before discarding any data. 

(iii) Water availability study may be done 

on site specific observed data. 

The project authorities may also 

calculate the PMF value using SUH 

approach as suggested in North 

Brahmaputra Basin (sub zone-2(a) report 

published by CWC by obtaining the PMP 

value and temporal distribution of rainfall 

from IMD and following 2 bells per day 

approach and incorporate this value also 

in the comparative study to get a more 

realistic value. 

(ii) Short interval data may be collected 

and the design flood should be reviewed 

based on observed data. 

available from May 2000 onwards and this 

data has been used in the 10-daily series 

developed at dam site. Even Pangin 

discharges for the period 1978-1994, have 

been converted at proposed Middle Siang 

dam site using linear regression equation 

developed between Pangin discharges and 

discharges at Middle Siang dam site. Hence, 

the observed data at Middle Siang dam site 

has not been discarded, rather it has been 

used for obtaining the average 10-daily 

series at Middle Siang dam site. 

(iii) No gauge-discharge observation has 

been made near proposed Naying project, 

the data of Raying (Middle Siang dam site) 

and Pangin, both are located on Siyom river 

d/s of proposed Naying H.E project has been 

used. For the time bieng these may be 

considered as site specific data. 

For such detailed studies as suggested for 

this stage i.e PFR, neither the database is at 

all sufficient nor necessacity felt by us. 

During feasibility stage, 

deterministic/probabilistic approach will be 

used, based on more observed data. 

Regarding the 2-bell theory, it is pertinent to 

mention that NHPC has already explained its 

stand in earlier discussions with CWC 

officials during the clearance of Teesta Low 

Dam, Stage-III and Subansiri Basin projects 

and also vide our letter no. NH/DD/HYD/564 

dt. 4.2.03. Again vide our letter no. 

NH/DD/HYD/2656 dt 17.7.03 we have stated 

this fact along with the letter received from 

IMD (ref. HS-DS(Dam)302/II dt.2 nd July 2003. 

(ii) It is not felt necessary to perform such 

detailed study during PFR stage.

Sedimenta 

tion 

The sedimentation rate for the region is 

about 0.1765 Ham/Sq.km/year as per 

CWC studies published in the 

Compendium on silting of reservoirs in 

India, which is higher than the rate 

proposed for the project. As stated in the 

report more detail study is required. 

As per the terms of preparation of PFRs 

and as emphasized in the meetings 

conducted by CEA sedimentation studies 

are required to be carried out and 

incorporated in the PFRs. 

General The PFR must bring out the limitations of 

the hydrological studies carried out for 

the PFR and suggest improvements, 

specific recommendations for opening 

new hydrological stations, method of 

observations, data to be collected etc. 

may be given which will help us as 

guidance to the agency taking up the 

detail investigations/DPR must review 

the network in consultation with HSO, 

CWC. 

The hydrological studies for the PFR 

may be revised incorporating the above 

observations and resubmitted. 

We are aware of the findings of CWC studies 

published in the Compendium on silting of 

reservoirs in India. As per that report, the 

sediment rate varies from 0.05658 to 0.2785 

Ham/Sq.km/year for Indus, Ganga and 

Brahmaputra basin. But the silt rate adopted 

for this particular project has been calculated 

on the basis of observed sediment data at 

Middle Siang dam site and is more region 

specific than that given in “Compendium on 

silting of reservoirs in India”. 

The necessity of detailed sedimentation 

study showing the new zero elevation, 

revised area capacity curve etc. is not felt 

during PFR stage. 

The PFR has pointed out the limitation of the 

studies after each study and establishment of 

G&D site, rainfall stations etc. are also 

highlighted in the PFR.

APPENDIX – VIII 

Comments of CWC on Hydrology 

vide Letter No.4/330/2003 HYD NE/399 

Dt. 31-12-2003 & Reply of NHPC

Annexure-III 

REPLY OF CWC OBSERVATIONS RECEIVED VIDE LETTER NO.4/330/2003 HYD 

NE/399 DT. 31-12-2003 

Data & 

Consisten 

cy Checks 

Water 

Availability 

Studies 

CWC OBSERVATIONS REPLY OF NHPC 

NHPC in their reply stated that the 

rainfall data was not used in the 

analysis and hence not furnished in the 

report. The observed discharge data at 

Middle Siang Dam (MSD) have been 

statedly used to correlate with the 

Pangin site. But the data so used and 

the analysis done and the consistency 

checks on the data are not available in 

the report and has not been furnished in 

the reply also. All the rainfall data 

available U/S of MSD and the discharge 

data at MSD may be furnished 

alongwith the consistency checks done 

on it and the rainfall runoff relationship 

may be established and the same may 

be converted to the present project after 

applying catchment reduction factor. 

Pangin data used in the present Project 

may be appended separately. MSD 

series is not an approved series. The 

data and consistency checks done for 

the MSD Project may also be appended 

without which checking cannot be 

carried out. 

The need for water availability studies 

based on observed data need not be 

emphasized. In the absence of site 

specific data also, the reliability of the 

series transposed need to be 

The 10-daily series at Middle Siang 

Project on the basis of which water 

availability for Naying has been done 

can be referred from the DPR of 

Middle Siang Project which has 

already been submitted by NHPC to 

CWC in September 2003. All the 

consistency checks done on the data 

and detailed analysis for deriving the 

Middle Siang series has been 

explained in Chapter-3, “Water 

Availability Study” (Vol-III) of that 

report. 

Rainfall-runoff relationship could not 

be established, as concurrent rainfall 

data was not available in the 

catchment. Hence, rainfall data, which 

is a very short period, has not been 

furnished in the report. 

It is to emphasize here that for PFR 

stage such detailed analysis requiring 

study from IMD for obtaining average 

annual isohyets, was not felt. 

We are aware of the fact that the

established. 

The present series is a converted series 

of Pangin site which is located about 

100 km D/S of the project site. As 

stated in the report D/S of MSD 

recorded heavier rainfall as compared 

to U/S side and in our comments it was 

pointed out to take into account such 

rainfall variation. NHPC in their reply 

stated that no concurrent rainfall data 

was available for obtaining rainfall ratio. 

Even in the absence of site-specific 

data also, the values of average annual 

isohytel lines can be obtained from IMD 

and the ratio between the two areas can 

be utilised for the purpose of PFR to 

obtain a more reliable series. The 

same may be carried out. 

Rainfall runoff relationship may be 

established using the observed 

discharge data available at MSD, NHPC 

site (May 2000 onwards) and rainfall 

data of MSD catchment after applying 

necessary consistency checks. The 

same may be converted to the project 

site applying catchment reduction 

factor. The data and the analysis done 

and the results may be furnished for 

comparison. 

Some more projects have been 

proposed U/S of the present proposal 

and integrated water availability studies 

may be done incorporating the 

contribution from independent 

catchment of projects and likely 

releases from the U/S power houses. 

rainfall trend increases after Rotung, to 

which Passighat is located further 

downstream. The detail rainfall-runoff 

needs to be done after establishing 

proper network for the catchment and 

the data being observed at different 

stations by NHPC. 

The observed discharge data at MSD 

has been converted to Naying project 

damsite using catchment reduction 

factor. Though rainfall-runoff analysis 

has not been done as it was only 

about 3 years data, but consistency 

has been checked by co-relating the 

MSD observed discharge with 

discharge observed at Pangin for the 

same period and it is seen that a good 

co-relation exists between these two 

discharges. 

At present, no project exists upstream 

of the proposed project. Cascade 

development need to be done at a 

later stage.

Design 

Flood 

Sedimenta 

tion 

Four to five years concurrent rainfall 

runoff data base can be utilised to 

calculate design flood by unit 

hydrograph approach. However, in the 

absence of short interval concurrent 

rainfall runoff data the design flood may 

be calculated using relevant subzonal 

report of CWC taking into account the 

recommendations of 1993 workshop 

and by collecting PMP/SPS values from 

IMD. Results may be compared before 

recommending the design flood. The 

design flood studies done by NHPC are 

too empirical to be relied upon. 

The rate given in the compendium on 

siltation will be the most likely value 

after construction of projects and the 

same may be incorporated in the 

proposal stage. 

As per the terms of preparation of PFRs 

and as emphasised in the meetings 

conducted by CEA sedimentation 

studies are required to be carried out 

and incorporated in the PFR. However, 

such studies have not been given to 

HSO, CWC for vetting. 

The hydrological and 

hydrometeorological observations and 

the analysis done are too in sufficient to 

form any base for the future DPR. No 

base has been laid in the PFR for the 

As already explained in our earlier 

reply also, for such detailed studies as 

suggested for this stage i.e PFR, 

neither the database is at all sufficient 

nor necessacity felt by us. During 

feasibility stage, 

deterministic/probabilistic approach 

need be used, based on more 

observed data and information. 

As per report of “Compendium on 

silting of reservoirs in India”, the 

sediment rate varies from 0.05658 to 

0.2785 Ham/Sq.km/year for Indus, 

Ganga and Brahmaputra basin. But 

the silt rate adopted for this particular 

project has been calculated on the 

basis of observed sediment data at 

Middle Saing dam site and is more 

region specific than that given in the 

report. Also silt rate is usually 

calculated based on the observed 

sediment data at or near the proposed 

site. The necessity of detailed 

sedimentation study showing the new 

zero elevation, revised area capacity 

curve etc. is not felt during PFR stage.

DPR. HSO has no further comments 

on the hydrology chapter. 

The PFR must bring out the various 

limitations of the hydrological studies 

carried out for PFR and suggest 

improvements. Specific 

recommendation for opening new 

hydrological and hydrometeorological 

stations, method of obsrvations, data to 

be collected etc may be given, these 

will help as guidance to the agency 

undertaking detailed investigations. 

The agency taking up the detail 

investigations/DPR must review the 

network in consultation with HSO, 

CWC. 

The PFR has pointed out the limitation 

of the studies after each study and 

establishment of G&D site, rainfall 

stations etc. are also highlighted in the 

PFR. 

Moreover, all the CWC comments 

along with their replies are also being 

appended in the PFR’s for future 

reference.

APPENDIX – IX 

Comments of CMDD Directorate, CWC issued vide 

CWC U.O. No. 20/2/2003/CMDD(E&NE)/229 

dated 08.01.2004 & Reply of NHPC

Reply to the comments of CMDD Directorate, CWC issued vide 

CWC U.O. No. 20/2/2003/CMDD(E&NE)/229 dated 08.01.2004 

Naying H.E. Project (4X250 MW) 

Sl. 

No. 

COMMENTS of CWC REPLY of NHPC 

1 The reports should indicate Scheme has primarily been 

alternative layouts and alternative conceived from CEA’s outline 

locations of project components scheme. Alternative layouts and 

examined during the preparation of site selection process can be 

PFR to bring out their merits and optimised only when detailed 

demerits of each including that topographical and geological 

finally adopted in PFR. The reasons investigations are carried in DPR 

for rejecting the particular alternative 

should also be elucidated justifying 

the rejection. 

stage. 

2 The report should incorporate All the necessary drawings for 

following drawings: 

estimation of civil work quantities 

a) Layout of scheme on appropriate at pre-feasibility stage has been 

scale 

annexed in the PFR. 

b) Layout of river diversion 

arrangement 

c) Layout & typical L section and 

appropriate c/s of the water 

diversion/storage 

appropriate scale 

structure on 

Moreover, it should be noted that the 

drawings which has been provided 

in PFR are inadequate for estimation 

purposes for the dam structure as 

well as the diversion works. 

Necessary dimensioning should be 

done to make the drawings 

complete. 

3 Preliminary survey should be made 

to ensure the quality and quantity 

availability of construction materials. 

4 The PFR should include some 

geophysical informations about the 

dam location & which should be 

ensured by field study. 

5 The available contour map of Survey 

of India should be digitized and 

blown up to locate the different 

components of the project. 

Refer Chapter 4 of i.e. 

“Topographic and Geotechnical 

Aspects” Para 4.12 

No geophysical investigation of 

site was possible due to 

inadequate time and logistics. 

1:50000 scale, SOI toposheet 

duly digitilised with various 

components marked on it are 

already provided.

6 Reasons for providing 4 nos. of 

upper level openings should be 

incorporated in PFR. 

7 For river diversion purposes non 

monsoon flood of 2000 cumecs has 

been considered. But the reason for 

considering this value has not been 

furnished. Moreover construction 

sluices have also been provided in 

addition to 2 nos. of diversion 

tunnels. Justification for providing 

the sluices may be added in the 

concerned chapter. 

8 Sale price of energy generated has 

been worked out Rs. 2.83 per unit 

which seems to on as higher side. 

This aspect may be looked into. 

9 Sediment loads plays a havoc to 

reduce the capacity of the reservoir 

and of the proposed generation. As 

such proper study should be done to 

accommodate its effect and the 

economical approach is etc. 

10 The PFR should include some 

geophysical informations about the 

dam location, which should be 

ensured by field study. 

The flood release has been 

considered partly through upper 

spillways and parts through lower 

spillways. The arrangement shall 

be reviewed at DPR stage, if 

required. 

As the diversion tunnels has been 

provided to cater the nonmonsoon 

flood only. During 

monsoon the additional 

requirement of diversion shall be 

met with the under sluices. 

- 

Provision of low level spillways 

and maintaining the reservoir in 

monsoon at MDDL and annual 

flushing of reservoir (if possible) 

are some of the provisions 

considered to ensure long life of 

the reservoir. 

No geophysical investigation of 

the site was possible due to 

inadequate time and logistics.

APPENDIX – X 

Comments of HCD (E&NE), Directorate CWC 

issued vide U.O. No. 3/5/2000-HCD(E&NE)/711 

dated 08.01.2004 & Reply of NHPC

Replying to the comments of HCD (E&NE), Directorate CWC 

issued vide U.O. No. 3/5/2000-HCD(E&NE)/711 dated 08.01.2004 

Naying H.E. Project (4x250MW) Arunachal Pradesh 

Sl. 

No. 

COMMENTS of CWC REPLY of NHPC 

1 Provision of desilting arrangement, if required, with It is not practical to provide 

observed silt data be made. 

desilting basins, due to very 

high design discharge of 

water conductor system. A 

100 m high dam with 

reservoir flushing through 

under sluces ensures that 

desilting basins can be 

2 

dispensed with. 

All water conductor components like surge shaft All water conductor system 

etc. be shown in the General Layout Plan. 

including surge shaft has 

been shown in downstream 

underground works General 

Layout Plan. 

3 HRT alignment needs to be reviewed for provision The HRT layout has been 

of intermediate construction adit and also the HRT 

should have sufficient rock covers. 

accordingly modified. 

4 Construction adits for the Surge shafts bottom, All the major adits have 

vertical limb of pressure shaft be also shown in the been incorporated in water 

layout plan. 

conductor system L-section. 

5 Sizing, shape & location of surge shaft needs to be Shall be taken up at 

reviewed with detailed transient studies. 

appropriate time 

6 Location of vertical drop/limb of the pressure shaft Optimisation of layout shall 

be closed to the powerhouse cavern so as 

minimum length of the steel liner be subjected to 

maximum pressure. 

be carried out at DPR stage. 

7 Main access tunnel to the machine hall service bay Modified layout plan and L- 

is shown to be through transformer cavern whose section of water conductor 

floor level has been shown much higher than the system is included in the 

service bay floor. As such layout of MAT needs to 

be reviewed. 

report. 

8 From construction point of view it will be very The same construction 

difficult to achieve the rock ledges/excavation methodology has been 

profile as shown in the drawing. 

adopted in many of NHPC 

projects. 

9 Purpose of providing trusses in the under ground No trusses have been 

caverns needs to be clarified. 

proposed in the 

underground cavern. The 

arrangement shown indicate 

the hanging arrangement of 

false ceiling. 

10 It will be preferable to have transformer cavern floor Modification to this has 

and service bay floor at same elevation to have already been made in the 

horizontal Bus ducts. Electro-mechanical relevant drawing. 

equipments can be accommodated in the horizontal 

Bus ducts and transformer hall size be optimized 

accordingly.

APPENDIX – XI 

NRSA Report on Initial Environmental Studies

Naying - Ministry of Power

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