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KVK PAR POWER PRIVATE LTD.

Par Hydroelectric Project (52 MW)

July 2014

Power Division

161133-40ER-0007-00

DETAILED PROJECT REPORT

VOLUME-I (Part-I)

MAIN REPORT (Chapters 1 to 8)

Par Hydroelectric Project (52 MW) Detailed Project Report

161133-47ER-0007-00

NOTICE

This document contains the expression of the professional opinion of SNC-Lavalin Engineering India Private Limited. (“SLEI”) as to the matters set out herein, using its professional judgment and reasonable care. It is to be read in the context of agreement dated 09th September, 2011 (the “Agreement”) between SLEI and the Client, and the methodology, procedures and techniques used, SLEI’s assumptions, and the circumstances and constrains under which its mandate was performed. This document is written solely for the purpose stated in the Work Order, and for the sole and exclusive benefit of the Client, whose remedies are limited to those set out in the Work Order. This document is meant to be read as a whole, and sections or parts thereof should thus not be read or relied upon out of context. SLEI has, in preparing the cost estimates, followed methodology and procedures, and exercised due care consistent with the intended level of accuracy, using its professional judgment and reasonable care, and is thus of the opinion that there is a high probability that actual costs will fall within the specified error margin. However, no warranty should be implied as to the accuracy of estimates. Unless expressly stated otherwise, assumptions, data and information supplied by, or gathered from other sources (including the Client, other consultants etc.) upon which SLEI’s opinion as set out herein is based has not been verified by SLEI; SLEI makes no representation as to its accuracy and disclaims all liability with respect thereto. SLEI disclaims any liability to the Client and to third parties in respect of the publication, reference, quoting, or distribution of this report or any of its contents to and reliance thereon by any third party.

July 2014

Power Division

161133-40ER-0007-00

KVK PAR POWER PRIVATE LTD.

PAR HYDROELECTRIC PROJECT (52 MW)

DETAILED PROJECT REPORT

EXECUTIVE SUMMARY

VOLUME-I : MAIN REPORT

VOLUME-II : BILL OF QUANTITIES & COST ESTIMATION

VOLUME-III : DRAWINGS

VOLUME-IV : APPENDICES


Volume-I (Part-I)Main Report

161133-40ER-0007-00 Page 1 of 1

DPR CONTENTS – VOLUME WISE

Executive Summary

Volume-I : Main Report

Part-I : Chapters 1 to 8

Check List Proforma

Salient Features

Chapter 1 : Introduction

Chapter 2 : Project Area

Chapter 3 : Need for the Project

Chapter 4 : Data Collection and Field Investigation

Chapter 5 : Project Hydrology

Chapter 6 : Project Geology

Chapter 7 : Power Potential Study

Chapter 8 :Design & Description of Civil Engineering Structures

Part-II : Chapters 9 to 17

Chapter 9 : Hydro-mechanical Equipment

Chapter 10 Power Plant Equipment

Chapter 11 : Construction Methodology & Equipment Planning

Chapter 12 : Construction Material

Chapter 13 : Infrastructure Works

Chapter 14 : Project Management Plan

Chapter 15 : Environmental & Ecological Aspects

Chapter 16 : Cost Estimation

Chapter 17 : Economic Evaluation

Volume-II : Bill of Quantities & Cost Estimation

Chapter-1 : Abstract of Cost Estimate

Chapter-2 : Detail Cost of Civil, Hydro-mechanical and Electromechanical Works

Chapter-3 : Item Rate Analysis of Major Civil Works

Chapter-4 : Analysis of Hourly Use Rate of Major Equipments

Volume-III : Drawings

(Project Geology, Civil, Hydro-Mechanical and Electromechanical Equipments)

Volume-IV : Appendices

Appendix-A : Hydro-meteorological, G&D Data

Appendix-B : Report on Laboratory Tests

Appendix-C : Geological Data



161133-40ER-0007-00

CHECK LIST PERFORMA

Par Hydroelectric Project (52 MW) Detailed Project Report Check List

161133-40ER-0007-00 Page 1 of 5

CHECK LIST

1. NAME OF THE PROJECT Par Hydroelectric Project

(52 MW)

2. LOCATION

State Arunachal Pradesh

District Papum Pare

Nearest Village Sagalee village

3. CATEGORY OF THE PROJECT Run-of-the-river,

Small Hydroelectric Project

4. PLANNING

Have the alternative proposals been studied

and their merits and demerits discussed?

Yes

Have the detailed topographical survey been

carried out for the following items and

drawings prepared as per prescribed scale?

o Stream surveys Yes

o Head works surveys (Weir or diversion

structure)

Yes

o Plant site and campsite Yes

o Water conductor system Yes

o Powerhouse, switchyard, tailrace Yes

o Penstock, Surge shaft Yes

o Communication etc. Yes


161133-40ER-0007-00 Page 2 of 5

5. GEOLOGY

Have the geological surveys for head works,

powerhouse, tailrace etc. been carried out

and report on general geology of the area and

on geology of the sites of principal structures

appended?

Yes

6. FOUNDATION INVESTIGATION

Have the foundation investigation for the

major civil structures and of the schemes etc.

been carried out

Yes

7. MATERIAL SURVEYS

Have the survey and laboratory test for the

Construction material like pervious &

impervious soil, sand, aggregates etc. carried

out?

Yes

8. HYDROLOGICAL & METEOROLOGICAL

INVESTIGATIONS

Have the hydrological and meteorological

investigations been carried out and status of

data discussed in report?

o Rainfall in the catchment Yes

o Gauge and discharge data of the Stream Yes

9. HYDROLOGY

Have hydrological survey been carried out to

establish the availability of water for the

benefits envisaged and what is the

dependability of the potential?

Yes


161133-40ER-0007-00 Page 3 of 5

10. LAND ACQUISITION & RE-SETTLEMENT

(Wherever applicable)

Have the provisions for the land acquisition

been considered?

Yes

Have the socio-economic problems involved

in re-settlement been investigated and

discussed?

Re-settlement not involved

11. DESIGN

Has the layout of the project area viz. location

of diversion structure, water conductor

system, powerhouse and tailrace been

finalized?

Yes

Have the preliminary designs been prepared

for the following components?

o Diversion structure Yes

o Penstock & Water conductor system Yes

o Powerhouse & switch yard Yes

o Powerhouse equipment, LT Ht switching

equipment and control and protection

equipment

Yes

o Steel of various sizes and type of

reinforcement

Yes

o Other materials – cement, electricity

explosives etc.

Yes

12. POWER BENEFITS

Have the following points discussed?

o Total energy production and installed

capacity of the grid system

Yes

o How does the scheme fit into overall

development of power of the region?

Yes


161133-40ER-0007-00 Page 4 of 5

o Energy generated from the project, firm

power, seasonal power and total power

Yes

o Proposal for transmission and or

connecting the existing system

Yes

o Cost of generation per kW installed

capacity as per kWh generated as

compared to the various small/mini/

micro-hydel projects and various

services in the region to justify the

economic variability of scheme

Yes

13. CONSTRUCTION PROGRAM

Are the major components of work projects to

be done departmentally or through

contractor?

Have the year/month-wise quantities of the

following items been worked out for various

components of the project (Total quantity)

o Excavation – soft and hard strata Yes

o Earth work in filling Yes

o Stone for masonry Yes

o Coarse aggregate for concrete Yes

o Steel of various size and type of

Reinforcement

Yes

o Cement Yes

o Other material – POL electricity,

explosive etc.

Yes

14. ESTIMATES

Is the estimate prepared Yes


161133-40ER-0007-00 Page 5 of 5

Have the analysis of rates for various major

items and the components of the project been

furnished with analysis and the price index at

which estimate is based?

Yes

15. ECOLOGICAL & ENVIRONMENTAL ASPECTS

Is the area likely to have any environmental

and ecological problems due to alternate

surface water pattern and preventive

/corrective measures discussed? (Whichever

applicable)

No environmental and

ecological degradation is

expected.

16. CAMPS AND BUILDINGS

Have the provisions for camps/ buildings

made Expenses

Yes, in the establishment

17. SOIL CONSERVATION

Is the need for soil conservation measures in

the project discussed?

Not applicable



161133-40ER-0007-00

SALIENT FEATURES

Par Hydroelectric Project (52 MW) Detailed Project Report Salient Features

161133-40ER-0007-00 S-1

SALIENT FEATURES

Project Location

o State : Arunachal Pradesh

o District : Papum Pare

o River : Pare

o Vicinity : Sagalee village

Hydrology

o Catchment area : 420 km2

o Max Discharge -10-Daily : 133.23 cumec

o Min discharge -10-Daily : 3.96 cumec

o Standard Project Flood (SPF) : 3060 cumec

o 100 Year Flood : 2759 cumec

Reservoir

o Full Reservoir Level (F.R.L) : El 848.0m

o Minimum Draw-down Level (M.D.D.L) : El 845.0m

o Gross Storage at FRL : 1.17 MCM

o Live storage : 0.35 MCM

o Length of submergence : 2000m

o Area under submergence at FRL : 14.44 Ha

River Diversion (During Construction)

o Diversion Arrangement : Diversion channel through one

half of river

o Diversion Discharge : 424 cumec

Spillway

o Latitude : 27° 14’ 33” N

o Longitude : 93° 30’ 43” E

o Top of Barrage : El 850.0m


161133-40ER-0007-00 S-2

o Crest Level of Spillway : El 823.50m

o Spillway Foundation Level (Lowest) : El 811.0m

o Spillway Height from crest Level : 26.5m

o Gate Type and Size (WxH) : 4 nos. Radial Gates; 6.5m x

10.6m

o Hoist Type and Capacity : Twin Hydraulic Hoist (2 x 65 MT)

o Stop log Type and Size (WxH) : Vertical lift slide type, 6.5m x

12.8m

o Hoist Type and Capacity : Gantry Crane, 20 MT

Intake

o Design Discharge (Including flushing

discharge)

: 34.19 cumec

o No. of Trash rack bays & height : 2 nos (3.5m x 12m)

o Sill level of Trash rack : El 838.0m

o Trash rack panel size : 3.78m (W) x 2.031m (H)

o Total number of panels : 2 x 6

o Intake Gate : Stop log, Vertical lift wheel type

o Bottom elevation of intake Gate : El 840.00m

o Intake Gate Size (WxH) : 1 no. (3.5m x 9.76m) each bay

o Hoist Type and Capacity : Rope drum hoist, 16 MT

o Number of Feeder Channels : 2 nos.

o Size of Feeder channels (WxH) : 3.5m x 10.00m

Desilting Basins

o Desilting Basin Size (LxWxH) : 2 nos. (100m x 8.50m x 13.0m)

o Size of Particle to be Removed : >0.2mm

o Design Discharge for each Basin : 17.09 cumec

o Flushing Discharge for each Basin : 2.85 cumec

o Flushing Duct Size (WxH) : 0.7m (W) x 1.2m (H) depth

variable


161133-40ER-0007-00 S-3

o No. of Trash rack bays at end of

Desilting

: 4 Nos.

o Size of Trash rack (W x H) : 3.75m x 10.00m

o Bottom level of Trash rack : El 840.00m

o Desilting Chambers outlet Gate : Vertical lift Slide type

o Gate Size (WxH) : 1 no. (5.0m x 9.76m)

o Hoist Type and Capacity : Mono rail hoist, 18 T

o Nos. of Flushing Ducts : 2 Nos

o Flushing Duct Gate : Vertical lift slide type

o Flushing Channel Gate Size (WxH) : 2 nos. in each duct (0.7m x

1.2m)

Headrace Tunnel

o Type : Concrete lined & steel lined in

low cover zone

o Concrete Lined

- Shape of HRT : Modified D shaped

- Diameter of the Tunnel : 3.5m (W) x 4.25m (H)

- Concrete lining thickness : 250mm

o Steel lined

- Shape of HRT : Circular shaped

- Diameter of the Tunnel : 3.6m

- Total Length of HRT : 8636m

- Design Discharge : 28.49 cumec

Adit

o Intermediate Adit to HRT : 5m (W) x 6m (H), 394m long

Surge Shaft

o Type : Open to the surface Restricted

Orifice type, Vertical Shaft

o Diameter : 7.5m


161133-40ER-0007-00 S-4

o Orifice : 1500mm dia circular orifice

o Total Height : 81.0m

o Top elevation : El. 876.5m

o Bottom elevation : El. 795.50m

Pressure Shaft

o Number and Diameter : One / 2.5m

o Thickness of Liner : 12-22mm

o Type of Steel : ASTM A537 Class II

o Total Length of Main Pressure Shaft : 481m

o Design Discharge through Pressure

Shaft

: 28.49 cumec

Unit Penstocks (After Bifurcation)

o Number and Diameter : 2 nos., 1.8m

o Thickness of Liner : 22mm

o Type of Steel : ASTM A537 Class II

o Length of unit penstock : 27m

o Design Discharge through each

Penstock

: 14.25 cumec

Main Inlet Valve

o Type : Spherical valve

o Number : 2 nos.

o Axis Elevation : 626.25m a.s.l.

o Diameter : 1.4m

Surface Powerhouse

o Latitude : 27° 13’ 11”N

o Longitude : 93° 34’ 55”E

o Dimensions (L X W X H) : 48.5m x 17.0m x 30.35m


161133-40ER-0007-00 S-5

o Turbine Type : Francis

o Number of Units : 2 nos.

o Elevation of Turbine Center Line : El 626.25m

o Rated Discharge per Unit : 14.25 cumec

o Turbine Speed : 500 rpm

o Net Head : 202.0

o Installed Capacity : 2 x 26 MW

o EOT Crane capacity (Power House) : 1 No. 80/ 20 MT

Draft Tube Gates

o Type of Gate : Vertical Lift Slide Type

o Gate Size (WxH) : 2 nos., 4.5m x 2.22m

o Hoist Type and Capacity : Gantry Crane, 10 MT

Generator

o Type : Suspended type

o Number : 2 nos.

o Rated Capacity : 28.89 MVA

o Generator Voltage / Frequency : 11 kV / 50Hz

o Power Load Factor (CosØ) : 0.9

Step Up Transformer

o Voltage Ratio : 11kV/ 132kV

o Rating : 3Ф, 32 MVA

Tailrace Channel

o Length : 32.86m

o Width : 20m

o Slope : 1V : 4H

o Outlet Sill Elevation : 630.0m. a.s.l


161133-40ER-0007-00 S-6

Switch Yard

o Type : Out door

o Area (L x W) : 40m x 50m

Estimated Cost

o Civil Works including HM works : 273.70 Crores

o E&M Works : 72.20 Crores

o Total Basic Cost : 345.90 Crores

o Escalation Cost : 80.96 Crores

o IDC and Financing Charges : 65.84 Crores

o Total Project Cost : 492.70 Crores

o Cost per MW : 9.48 Crores

o Cost per MU : 2.59 Crores

Power Benefits

o 90% dep. Energy : 190.25 MU

o 50% dep. Energy : 295.01 MU

Financial Aspects (at Powerhouse bus bar) - 35 Years Operation

o Levellised Tariff / kWh (with free power

to the State), /kWh

: 5.72

o 1st Year Tariff (with free power to the

State), /kWh

: 6.61

o Levellised Tariff / kWh (without free

power to the State), /kWh

: 5.03

Construction Period

o Construction Period : 4 Years 6 Months after 1 year

of pre-construction period



161133-40ER-0007-00

CHAPTER - 1 Introduction



161133-40ER-0007-00 i

TABLE OF CONTENTS

PAGE NO.

1 INTRODUCTION ...................................................................................................... 1-1

1.1 General ......................................................................................................... 1-1

1.2 River System ................................................................................................ 1-2

1.3 Location ........................................................................................................ 1-2

1.4 The Par Project ............................................................................................ 1-3

1.5 Organization of the Report ........................................................................... 1-3

1.6 The Consultant ............................................................................................. 1-5

1.7 Acknowledgement ........................................................................................ 1-5



161133-40ER-0007-00 i

LIST OF FIGURES

PAGE NO.

Figure 1-1: Project Location ................................................................................................. 1-1

Figure 1-2: Google Earth Image of the Project Area ............................................................ 1-3



161133-40ER-0007-00 1-1

1 INTRODUCTION

1.1 General

The Par hydroelectric project is the first project from upstream in the cascade development

of hydroelectric projects on the Pare River. From upstream to downstream of Pare River, the

development of the projects are in this order – Par Hydroelectric Project, Turu Hydroelectric

Project, Dardu Hydroelectric Project and Pare Hydroelectric Project (project under

construction by NEEPCO).

The project is located in Papum Pare District in the State of Arunachal Pradesh. It envisages

utilization of the flow of Pare River, a tributary of Brahmaputra River, for generation of

electrical power in a run-of-the-river scheme. The project location is shown in Figure 1-1

and Figure 1-2.

Figure 1-1: Project Location

The Pre-Feasibility Report for the Par hydroelectric Project was prepared by Aquagreen

Engineering Management Pvt. Ltd. Subsequently Feasibility Study Report was prepared by

SNC-Lavalin Engineering India Pvt. Ltd.



161133-40ER-0007-00 1-2

1.2 River System

The Pare, Panior and Dikrong are the main rivers of the Papum Pare district. A short

description of river system is discussed in subsequent paras.

Panior: The Panior river rises from a high mountain called Khoren Putu lying to the

northwest of Sagalee. A tributary called Pareing also feeds the river formed by two

streams-Nirpung and Nirke. The Panior known in the plains of Assam as Ranga-Nadi falls

into Brahmaputra. The Ranga-Nadi hydroelectric project is built on this river.

Pare: The River Pare originates at elevation of about 2850m as Pare nadi in the Lower

Subansiri district. After flowing or about 24km from North to South, the Pare takes an

eastward turn and flows for about 43km upto Sekhi. On the way, it passes through Sagalee.

After the confluence of Kheel nallah from right Bank and Shu nallah from left bank the river is

called Dikrong. The river (Pare/ Dikrong) then flows for about 18kms upto the Pare

hydroelectric project dam site near Jampa. The river ultimately discharges into the

Brahmaputra.

Dikrong: Dikrong drains the southern part of the district. The Par, Nirochi and Pachin rivers

form it. It flows from the west to the southeast, and passing through Itanagar region and

merges with Brahmaputra in the Lakhimpur district of Assam.

1.3 Location

The proposed Par hydroelectric project is located on Pare River downstream of Sagalee

village. The Latitude and Longitude of the Diversion Barrage and the Powerhouse sites are

as given below:

Barrage Powerhouse

Latitude: 27°14’33” N 27°13’11” N

Longitude: 93°30’43” E 93°34’55” E

The satellite image of the project area can be viewed in Figure 1-2.



161133-40ER-0007-00 1-3

Figure 1-2: Google Earth Image of the Project Area

1.4 The Par Project

The Par Hydroelectric Project envisages utilization of water of river Pare by constructing a

diversion structure near Sagalee village. The project site is approachable from Itanagar/

Naharlagun. The diversion site is approachable by road from Kheel village. The diversion

site and powerhouse site is about 77km and 64km away from the Naharlagun, respectively.

The water conductor system is envisaged on the left bank of Par River. The intake is located

on the left bank and it leads to a surface desilting basins. Two desilting basins are proposed

considering the amount of water diverted into the system. A modified D-shaped

Headrace Tunnel (some part steel conduit) ending in a open to sky surge shaft with restrict

orifice type then a pressure shaft off takes from the surge shaft leading to a surface

powerhouse proposed to be located on a river terrace on its left bank.

Detailed layout and design aspects of the project are described in subsequent sections of

this report.

1.5 Organization of the Report

This Detailed Project Report (DPR) describes the techno economical aspects of

Par Hydroelectric Project. The report is organized in four volumes. Detailed structure of

project report is described below:



161133-40ER-0007-00 1-4

Executive Summary

Volume-I : Main Report

o Part-I

- Salient Features

- Chapter-1 : Introduction

- Chapter-2 : Project Area

- Chapter-3 : Need for the Project

- Chapter-4 : Data Collection and Field Investigation

- Chapter-5 : Project Hydrology

- Chapter-6 : Project Geology

- Chapter-7 : Power Potential Study

- Chapter-8 : Design & Description of Civil Engineering Structures

o Part-II

- Chapter-9 : Hydro-mechanical Equipment

- Chapter-10 : Power Plant Equipment

- Chapter-11 : Construction Methodology & Equipment Planning

- Chapter-12 : Construction Material

- Chapter-13 : Infrastructure Works

- Chapter-14 : Project Management Plan

- Chapter-15 : Environmental & Ecological Aspects

- Chapter-16 : Cost Estimation

- Chapter-17 : Economic Evaluation

Volume-II : Bill of Quantities & Cost Estimation

Volume-III : Drawings (Civil, Geology, Hydro-mechanical & Electromechanical)

Volume-IV : Appendices

o Appendix-A Hydro-meteorological, G&D Data

o Appendix-B Report on Laboratory Tests

o Appendix-C Geological Data



161133-40ER-0007-00 1-5

1.6 The Consultant

KVK Par Power Pvt. Ltd. has appointed SNC-Lavalin Engineering India Pvt. Ltd. (SLEI) as

its consultant for the preparation of the DPR. At this stage of the project, Detailed Project

Report has been prepared to facilitate the Owner to submit the same to the Govt. of

Arunachal Pradesh to obtain necessary statutory clearances. SLEI is a wholly owned

subsidiary of SNC-Lavalin Inc. (SLI) of Montreal, Canada and its office in Delhi is an

extension of Hydro Division of SLI.

SNC-Lavalin’s Hydro Division, based in Montreal, Canada, has participated in the

development of hydroelectric projects operating under heads ranging from 5 m to over

800 m, with a total cumulative installed capacity of more than 250000 MW. It has designed

and managed construction of underground and surface powerhouses; concrete arch,

concrete gravity, earthfill, rockfill, masonry and roller-compacted concrete dams.

The Division has designed and managed the driving of power tunnels in geological

conditions as diverse as the granite of the Canadian Shield and the metamorphic-volcanic

rocks of the Himalayas. With its wide experience at home and abroad, the Division has

become the leading exporter of Canadian hydroelectric technology. The Division has been

involved in design and engineering of several important hydroelectric projects around the

world, including several in India.

SNC-Lavalin’s Hydro Division has established a design and engineering office in Delhi

where it employs around 125 full-time personnel including technical and administrative staff.

In addition, it has a pool of several specialist local consultants whose services are availed on

specific tasks, as required. The Indian office has access to, and regularly uses, the expertise

of Canadian hydro specialists of SNC-Lavalin.

1.7 Acknowledgement

SLEI sincerely acknowledges the support provided by the Owner during the preparation of

this report. Cooperation extended by the Owner in providing all the pertinent information

required for completion of this report is also gratefully acknowledged.



161133-40ER-0007-00

CHAPTER - 2 Project area



161133-40ER-0007-00 i

TABLE OF CONTENTS

PAGE NO.

2 PROJECT AREA ..................................................................................................... 2-1

2.1 Geographic Features .................................................................................... 2-1

2.2 Topographic Features .................................................................................. 2-1

2.3 Climate ......................................................................................................... 2-1

2.4 Socio-Economic Aspects .............................................................................. 2-2

2.4.1 Demographic Features ..................................................................... 2-2

2.4.2 Ethnographic Details and Religion .................................................... 2-2

2.4.3 Health and Education ....................................................................... 2-3

2.4.4 Trade & Industry ............................................................................... 2-3

2.4.5 Natural Resources ............................................................................ 2-4

2.5 Papum Pare District ..................................................................................... 2-4

2.6 Hydropower Potential ................................................................................... 2-5



161133-40ER-0007-00 2-1

2 PROJECT AREA

2.1 Geographic Features

Arunachal Pradesh is the easternmost state of India. Arunachal Pradesh shares its border

with the states of Assam to the south and Nagaland to the southeast. Burma/Myanmar lies

towards the east, Bhutan towards the west, and Tibet to the north. This region acquired an

independent political status in January 20, 1972, when it was declared as Union Territory

under the name of Arunachal Pradesh. The State of Arunachal Pradesh Bill was passed by

the Parliament in 1986 and with effect from February 20, 1987 Arunachal Pradesh became

the 24th state of Indian Union. Itanagar is the capital of the state.

Arunachal Pradesh is divided into sixteen districts. The state is mostly mountainous with the

Himalayan range along the northern borders criss-crossed with ranges running north-south.

These divide the state into five river valleys: the Kameng, the Subansiri, the Siang, the Lohit

and the Tirap. All these are fed by snow from the Himalayas and countless rivers and

rivulets.

2.2 Topographic Features

Arunachal Pradesh, one of the most sparsely populated states of India, covers an area of

83,743 sq.km. Arunachal is the largest state area-wise in the north-east region. Itanagar, the

capital is about 530m above mean sea level. Arunachal Pradesh has a long international

border with Bhutan to the west (160km), China to the north and north-east (1,080km) and

Myanmar to the east (440km). It stretches from snow-capped mountains in the north to the

plains of Brahmaputra valley in the south. The Himalayan ranges that extend up to the

eastern Arunachal separate it from China. The ranges extend toward Nagaland, and form a

boundary between India and Burma in Changlang and Tirap district, acting as a natural

barrier called Patkai Bum Hills. They are low mountains compared to the Greater Himalayas.

2.3 Climate

The weather and the climate of Arunachal Pradesh are quite unique from the rest of India.

The climate of Arunachal is governed by the Himalayan system and the altitudinal

differences. The climate here is highly hot and humid at the lower altitudes and in the valleys

wrapped by marshy thick forest particularly in the eastern region, while it becomes too cold

in the higher altitudes. Average temperature during the winter months range from

15 to 21 degree celsius and 22 to 30 degree celsius during monsoon. Between June and



161133-40ER-0007-00 2-2

August the temperature sometimes go up to 40 to 42 degree celsius. The rainfall of

Arunachal Pradesh is amongst the heaviest in the country. Arunachal Pradesh receives

about 80 to 160 inches (2,000 to 4,000mm) annually, most of it between May and

September.

2.4 Socio-Economic Aspects

2.4.1 Demographic Features

The population of Arunachal Pradesh is 1.1 million according to 2001 census and is

scattered over 16 towns and 4065 villages. The State has the lowest density of

13 persons per sq.km. As against decadal growth rate of 21.54% at the national level, the

population of the State has grown by 27% over the period 1991-2001. The sex ratio of

Arunachal Pradesh at 893 females to 1000 males is lower than the national average of 933.

Total literacy of the State rose to 44.24% from 41.59% in 1991. There are 20 major tribes

and a number of sub-tribes inhabiting the area. Most of these communities are ethnically

similar, having derived from and original common stock but their geographical isolation from

each other has brought amongst them certain distinctive characteristics in language, dress

and customs.

2.4.2 Ethnographic Details and Religion

Broadly the people may be divided into three cultural groups on the basis of their

socio-religious affinities.

The Monpas and Sherdukpens of Tawang and West Kameng districts follow the lamaistic

tradition of Mahayana Buddhism. Noted for their religious fervor, the villages of these

communities have richly decorated Buddhist temples, locally called 'Gompas'.

Though largely agriculturists practicing terrace cultivation, many of these people are also

pastoral and breed herds of yak and mountain sheep. Culturally similar to them are Membas

and Khambas who live in the high mountains along the northern borders. Khamptis and

Singphos inhabiting the eastern part of the State are Buddhists of Hinayana sect.

They are said to have migrated from Thailand and Burma long ago and still using ancient

scripts derived from their original homeland.

The second groups of the people are Adis, Akas, Apatanis, Bangnis, Nishis, Mishmis, Mijis,

Thongsas etc., who worship Sun and Moon God namely, Donyi-Polo and Abo-Tani,

the original ancestors for most of these tribes. Their religious rituals largely coincide with



161133-40ER-0007-00 2-3

phases of agricultural cycles. They invoke nature deities and make animal scarifices.

They traditionally practice jhumming or shifting cultivation. Adis and Apatanis extensively

practice wet rice cultivation and have a considerable agricultural economy. Apatanis are also

famous for their paddy-cum-pisciculture. They are specialised over centuries in harvesting

two crops of fish along with each crop of the paddy.

The third group comprises Noctes and Wanchos, adjoining Nagaland in the Tirap District.

These are hardy people known for their strictly structured village society in which hereditary

village chief still plays a vital role. The Noctes also practice elementary form of Vaishnavism.

2.4.3 Health and Education

In addition to the few general hospitals spread among the larger towns of Arunachal

Pradesh, nearly every district has its own hospital. In more remote areas, health services are

provided by 31 community health centres and 379 subcentres. Tuberculosis remains a major

concern in the state, with hospital facilities specifically designated as tuberculosis treatment

centres. The Total Fertility Rate of the State is 3.0. The Infant Mortality Rate is 37 and

Maternal Mortality Ratio is NA (SRS 2001-03). The Sex Ratio in the State is

893 (as compared to 933 for the country). Arunachal Pradesh has 299 Pre-nursery schools,

1251 Primary schools, 301 Middle schools, 87 High schools and 67 Higher secondary

schools. There are 3 Industrial Training Institutions and an Engineering college.

2.4.4 Trade & Industry

The state’s manufacturing sector consists primarily of medium and small-scale industries.

Basketry, weaving, and carpets are the main handicraft manufactures. Smaller-scale

industries include rice and oil milling, fruit processing, manufacture of forest-based products,

and steel fabrication. Sericulture (raw silk production) also is important, and the state

produces many varieties of silk yarns. Industrial expansion has been encouraged by the

state’s economic development policies, and industrial estates have been established at

Itanagar, Naharlagun (formerly Old Itanagar), Pasighat, and Deomali.

Arunachal Pradesh has significant, though largely unutilized, resource potential. Among its

resources for generating energy are rivers, coal, and petroleum; most of the state’s power is

provided by hydroelectric plants. In addition to hydrocarbons, other mineral resources of

Arunachal Pradesh include dolomite, quartzite, limestone, and marble.



161133-40ER-0007-00 2-4

For conservation and explorations of vast minerals, the Arunachal Pradesh Mineral

Development and Trading Corporation Limited (APMDTCL) were set up in 1991.

Namchik-Namphuk coal fields are taken up by APMDTCL. To provide training to craftsmen

in different trades, there are two Industrial Training Institutes at Roing and Daporijo.

2.4.5 Natural Resources

Bio-geographically, Arunachal is situated in the Eastern Himalayan province, the richest

biogeographical province of the Himalayan zone. The entire territory forms a complex hill

system with varying elevations ranging from 50m in the foot-hills and gradually ascending to

about 7000m, traversed throughout by a number of rivers and rivulets. Rainfall varies from

1000mm in higher reaches to 5,750mm in the foot-hill areas, spread over 8-9 months

excepting the drier days in winter. This diversity of topographical and climatic conditions has

favoured the growth of luxuriant forests which are home to myriad plant and animal forms

adding beauty to the landscape. Nature has been exceedingly kind and has endowed this

beautiful State of Arunachal Pradesh with diverse forests and magnificent wildlife.

The richness of life forms i.e. the flora & fauna that occur in these forests presents a

panorama of biological diversity with over 5000 plants, about 85 terrestrial mammals, over

500 birds and a large number of butterflies, insects and reptiles. Such an unparalleled

occurrence of life forms can be attributed to the peculiar location of the State which is at the

junction of the Paleoarctic, indo-Chinese, and Indo-Malayan bio-geographic regions, Biotic

elements from all these regions occur in this state making it very rich in floral & faunal

resources. The vegetation of Arunachal Pradesh falls under four broad climatic categories

and can be classified in five broad forest types with a sixth type of secondary forests.

These are tropical forests, sub tropical forests, pine forests, temperate forests and alpine

forests. In the degraded forests, bamboos and other grasses are of common occurrence.

2.5 Papum Pare District

The Papum Pare District, the capital district of Arunachal Pradesh is situated in the

North-Eastern part of India. The entire Papum Pare district is mountainous forming a part of

the Eastern Himalayas. The area comprises of a cross–section of the foothill region

adjoining the border of Assam, the lower hills and the lofty mountain extending northwards.

It is located in between latitude 26°55’ N and 28°40’ and longitude between 92°40’ and

94°21’. The district headquarter is located at Yupia, which is situated about 20km from

Itanagar.



161133-40ER-0007-00 2-5

It is a land of lush green forests, deep river valleys and beautiful plateau. The land is mostly

mountainous with Himalayan ranges. Trees of great size, plentiful of climbers, hundreds of

variety of orchids, cane and bamboos are found in the district.

The district occupies an area of approximately 2,875 sq.km inhabited by a population of

1,21,750. There are 274 villages and 2 towns in the district. Itanagar, the capital of the state

is situated in this district. The district is divided into two administrative subdivisions Sagalee

Sub-Division and Itanagar Capital Complex Sub-division. There are nine administrative

circles Sagalee, Mengio, Toru, Laiporiang, Kimin, Balijan, Doimukh, Itanagar and

Naharlagun.

Itanagar, the capital of Arunachal Pradesh, is about 394 kms from Guwahati and connected

by road and Pawan Hans helicopter service.

2.6 Hydropower Potential

Arunachal Pradesh, with more than 55000 MW hydropower potential, will be known as the

Power House of the country in few years time. In fact the experts say that the identified

potential of 5,5000 MW is a conservative estimate and the actual potential may run into

70,000 MW. Since past few years the State has taken up concerted efforts to harness

this potential by inviting the central public sector undertakings as well as private players to

participate in the process. The State has its own Hydro Power Policy which guides the

Government in the process of harnessing the power potential. It is worth mentioning

that though the State is a late starter as far as harnessing the megapotential, but for micro

hydel the process started way back in 1972.



161133-40ER-0007-00

CHAPTER - 3 Need for the project



161133-40ER-0007-00 i

TABLE OF CONTENTS

PAGE NO.

3 NEED FOR THE PROJECT ....................................................................................... 3-1

3.1 General ............................................................................................................... 3-1

3.2 The Par Hydroelectric Project ............................................................................ 3-2

3.3 Hydro Potential and Its Development ................................................................. 3-2

3.4 Power Demand and Supply Scenario in the Country ......................................... 3-3

3.5 Hydro Power Potential of North-Eastern Region ................................................ 3-4

3.6 Power Scenario of North-Eastern Region .......................................................... 3-6

3.7 Hydropower Potential of Arunachal Pradesh ..................................................... 3-8

3.8 Power Situation in Arunachal Pradesh ............................................................... 3-8

3.9 Development of Hydropower Demand ............................................................... 3-8

3.9.1 Present Status ....................................................................................... 3-8

3.9.2 Forecast ................................................................................................ 3-9

3.9.3 Long Term Plan ................................................................................... 3-10

3.10 Necessity and Justification for Implementing the Project ................................. 3-10



161133-40ER-0007-00 ii

LIST OF TABLES

PAGE NO.

Table 3-1: Sector-wise Installed Capacity of Power Utilities ................................................ 3-2

Table 3-2: Region-wise Installed Capacity of Power Utilities ............................................... 3-2

Table 3-3: Actual Power Supply Position of India ................................................................ 3-3

Table 3-4: Status of Projects commissioned during 11th Plan .............................................. 3-4

Table 3-5: Capacity addition target during the 12th Plan (in MW) ........................................ 3-4

Table 3-6: State-wise estimated hydroelectric potential of North-Eastern Region ............... 3-5

Table 3-7: State-wise Installed Capacity of North-Eastern Region ...................................... 3-6

Table 3-8: Sector-wise Installed Capacity of North-Eastern Region .................................... 3-6

Table 3-9: Actual Power Supply Position in North-Eastern Region ..................................... 3-7

Table 3-10: Likely capacity addition during 12th Plan (2012-17) in North-Eastern Region ... 3-7

Table 3-11: Likely capacity addition (Hydro) during 12th Plan (2012-17) in Arunachal Pradesh ............................................................................................. 3-8

Table 3-12: Plan-wise Growth of Hydropower ..................................................................... 3-9



161133-40ER-0007-00 3-1

3 NEED FOR THE PROJECT

3.1 General

Hydro power is the richest renewable and environmentally benign source of energy.

Hydroelectric stations have the inherent ability of instantaneous starting, stopping and

managing load variations, which helps in improving reliability of the power system.

Hydroelectric stations are the natural choice for meeting peak demand. The generation cost

is inflation free and, in fact, reduces over time. A hydroelectric project has a useful life

extending to well over 35 years and helps in conserving scarce fossil fuels.

Development of hydro power projects also provides the added advantage of opening up

avenues for development of remote and backward areas of the state. Despite being

recognised as a renewable source of energy, the share of hydro power in the overall

generating capacity in the country has been steadily declining since 1963. The share of

hydro power has declined from 44% in 1970 to about 16.5% today.

Several constraints have affected the pace of hydro power development, including

non-availability of long term financing and viability of tariff. Many hydro projects have been

adversely affected by geological surprises, especially during underground excavation.

Other problems arising out of the inaccessible and remote location of the site, delays in land

acquisitions and in resettlement of families affected by the projects have also slowed the

pace of hydro power development in the country.

Government of India has now accorded high priority to the development of hydro potential

and has taken a number of policy initiatives to address the issues impeding hydro power

development. In accordance with the latest hydro power policy (2008), the Government of

India is encouraging substantial private investment in hydro power development.

In order to hasten the progress of hydroelectric generation, a large number of projects have

been identified and their viability has been confirmed through pre-feasibility studies. Many of

these projects have been awarded to private developers who are actively engaged in their

implementation.



161133-40ER-0007-00 3-2

3.2 The Par Hydroelectric Project

Par Hydroelectric Project has been conceived as a run of the river scheme for exploitation of

power potential in a stretch of about 12km on Par river. This project will be supplementing

power generation in the North-Eastern region (structured on geographical congruity) which

comprises the states of Arunachal Pradesh, Assam, Manipur, Nagaland, Meghalaya, Tripura

and Mizoram. Power system in the region is mainly controlled by various central

government/state government utilities.

3.3 Hydro Potential and Its Development

The total installed capacity in the country, as on May 31, 2014, is 248,510 MW of which

hydroelectric schemes contribute 40,661 MW (~16.5%). All India and Region-wise installed

capacity of power utilities are given below in Table 3-1 and Table 3-2.

Table 3-1: Sector-wise Installed Capacity of Power Utilities

(Figures in MW)

Sector Hydro Thermal

Nuclear R.E.S Total Coal Gas Diesel Total

State 27482.00 54428.00 6974.42 602.61 62005.03 0.00 3803.67 93290.70

Private 2694.00 47215.38 8568.00 597.14 56380.52 0.00 27888.47 86962.99

Central 10485.41 45925.01 7065.53 0.00 52990.54 4780.00 0.00 68255.95

Total 40661.41 147568.39 22607.95 1199.75 171376.09 4780.00 31692.14 248509.64

Source: CEA Website

Table 3-2: Region-wise Installed Capacity of Power Utilities

(Figures in MW)


Nuclear R.E.S Total Coal Gas Diesel Total

Northern 16460.76 35883.50 5331.26 12.99 41227.75 1620.00 5935.77 65244.28

Western 7447.50 59114.51 10915.41 17.48 70047.40 1840.00 11271.07 90605.97

Southern 11398.03 26582.50 4962.78 939.32 32484.60 1320.00 13784.67 58987.30

Eastern 4113.12 25927.88 190.00 17.20 26135.08 0.00 432.86 30681.06

N Eastern 1242.00 60.00 1208.50 142.74 1411.24 0.00 256.67 2909.91

Islands 0.00 0.00 0.00 70.02 70.02 0.00 11.10 81.12

All India 40661.41 147568.39 22607.95 1199.75 171376.09 4780.00 31692.14 248509.64

Source: CEA website



161133-40ER-0007-00 3-3

Re-assessment Studies of hydroelectric potential of the country, completed by

Central Electricity Authority in 1987, have assessed the economically exploitable hydro

power potential in terms of installed capacity as 148,701 MW, of which 145,320 MW is from

schemes having capacity above 25 MW. Only about 24.6% of the hydro potential has been

harnessed so far while another 8.97% is under various stages of development.

3.4 Power Demand and Supply Scenario in the Country

The country has been facing growing shortages of power over the past five years. During the

11th Plan (2007 - 2012), the average energy shortage in the country was about

400 Billion kWh (10%).

Details of peak and energy shortages in the country from 7th Plan onwards are given in

Table 3-3 below:

Table 3-3: Actual Power Supply Position of India

Peak Demand

Peak availability

Surplus/Deficit Energy

RequirementEnergy

Availability Surplus/ Deficit

(MW) (MW) (MW) (%) (MU) (MU) (MU) (%)

At the end of 7th Plan (1989-90)

40385 33658 -6727 -16.7 247762 228151 -19611 -7.9


63853 52376 -11477 -18.0 413490 365900 -47590 -11.5


78441 69189 -9252 -11.8 522537 483350 -39187 -7.5


100715 86818 -13897 -13.8 690587 624495 -66092 -9.6

11th Plan

2007-08 108866 90793 -18073 -16.6 705724 628016 -77708 -11.0

2008-09 109809 96685 -13124 -12.0 774324 689021 -85303 -11.0

2009-10 119166 104009 -15157 -13.8 830594 746644 -83950 -10.1

2010-11 122287 110256 -12031 -9.8 861591 788355 -73236 -8.5

2011-12 130006 116191 -13815 -10.6 937199 857886 -79313 -8.5

12th Plan

2012-13 135453 123294 -12159 -9.0 998114 991,209 -89905 -8.7

2013 –14 135918 129815 -6103 -4.5 1002257 959829 -42428 -4.2

Apr 2014 – May 2014

141886 134972 -6914 -4.9 179867 172448 -7419 -4.1

Source: CEA Website



161133-40ER-0007-00 3-4

One of the major objectives of the National Electricity Policy was that demand should be fully

met by the year 2012 with all peaking and energy shortages to be removed. It was with this

objective in mind that a capacity addition of 78,700 MW was targeted for the 11th Five Year

Plan. Against this capacity of 54,964 MW was commissioned during the 11th Plan.

The details are as below:

Table 3-4: Status of Projects commissioned during 11th Plan

(Figures in MW)


Nuclear Total Coal Gas Lignite Total

Central 1550.0 11550.0 740.0 500.0 12790.0 880.0 15220.0

State 2702.0 11695.0 1885.4 450.0 14030.0 0.0 16732.4

Private 1292.0 18649.0 2530.5 540.0 21720.0 0.0 23012.5

Total 5544.0 41894.0 5155.9 1490.0 48540.0 880.0 54963.9

Source: CEA Website

A capacity addition of 88537 MW has been targeted for the 12th Five Year Plan break-up for

which is as below:

Table 3-5: Capacity addition target during the 12th Plan (in MW)


Nuclear Total Coal Lignite Gas/LNG Total

Central Sector 6004 13800 250 827.6 14878 5300 26182

State Sector 1608 12210 0 1712 13922 0 15530

Private Sector 3285 43270 270 0 43540 0 46825

All India 10897 69280 520 2539.6 72340 5300 88537

Source: CEA Website

Rigorous advance planning/action is clearly required to achieve these formidable targets.

3.5 Hydro Power Potential of North-Eastern Region

The North-Eastern Region (NER) of the country comprises seven states:

Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, and Tripura.

The area is endowed with bountiful water resources with Brahmaputra flowing in the

northern part and the Barak (Meghna) flowing through the southern margins. These two



161133-40ER-0007-00 3-5

rivers, along with their numerous tributaries, have created a very dynamic and powerful

hydrologic regime in the region.

The Brahmaputra in the northern part and the Barak (Meghna) flowing through the southern

margins along with their numerous tributaries are the two main river systems that have

created a very dynamic and powerful hydrologic regime in the region.

As per Re-assessment Studies carried out by CEA, hydro potential of the north-eastern

region in terms of installed capacity has been estimated as 58,971 MW (58,356 MW of

schemes above 25 MW capacity) i.e. almost 40% of the country's total hydro potential.

Out of the above, 1242 MW (schemes above 25 MW capacity) have been harnessed,

while projects amounting to 2810 MW are under construction, as on May 31, 2014.

The state-wise estimated hydroelectric potential of the north-eastern region and its status of

development, as on May 31, 2014, is given below:

Table 3-6: State-wise estimated hydroelectric potential of North-Eastern Region

State Identified Potential as

per Re-assessment Study (MW)

Capacity Developed (schemes above

25 MW capacity) (MW)

Capacity Under Construction

(schemes above 25 MW capacity) (MW)

Arunachal Pradesh 50328 405 2710

Assam 680 375 0

Manipur 1784 105 0

Meghalaya 2394 282 40

Mizoram 2196 0 60

Nagaland 1574 75 0

Tripura 15 0 0

Total 58971 1242 2810

Source: CEA Website

Additionally, the Region also has abundant resource of coal, oil and gas for thermal power

generation. In spite of such huge potential the region ranks lowest in the country in terms of

per capita energy consumption. This has been mainly due to inhospitable climatic conditions,

remote location and inaccessibility of geographical locations

However with continual improvement of infrastructure and communication facilities, the North

East region stands to become the power house of India by utilizing its surplus power

potential especially in the hydro power sector.



161133-40ER-0007-00 3-6

Thus, generating power from the utilizable water resources of the north-east to augment

development efforts in the country as well as the region is a legitimate pursuit.

3.6 Power Scenario of North-Eastern Region

With respect to the total available power potential of the region, the actual installed capacity

and power supply position, as on May 31, 2014 are given below in Table 3-7 to Table 3-9.

Table 3-7: State-wise Installed Capacity of North-Eastern Region

(Figures in MW)

State Hydro Thermal

Nuclear RES Total Coal Gas Diesel Total

Arunachal Pradesh

97.57 0.00 32.05 15.88 47.93 0.00 103.93 249.43

Assam 429.72 60.00 598.52 20.69 679.21 0.00 34.11 1143.04

Manipur 80.98 0.00 46.96 45.41 92.37 0.00 5.45 178.80

Meghalaya 356.58 0.00 65.61 2.05 67.66 0.00 31.03 455.27

Mizoram 34.31 0.00 27.28 51.86 79.14 0.00 36.47 149.92

Nagaland 53.32 0.00 32.84 2.00 34.84 0.00 29.67 117.83

Tripura 62.37 0.00 349.84 4.85 354.69 0.00 16.01 433.07

Central 127.15 0.00 55.40 0.00 55.40 0.00 0.00 182.55

TOTAL 1242.00 60.00 1208.50 142.74 1411.24 0.00 256.67 2909.91

Source: CEA website

Table 3-8: Sector-wise Installed Capacity of North-Eastern Region

(Figures in MW)

State Hydro Thermal

Nuclear RES Total Coal Gas Diesel Total

State 382.00 60.00 445.70 142.74 648.44 0.00 256.64 1287.08

Private 0.00 0.00 24.50 0.00 24.50 0.00 0.03 24.53

Central 860.00 0.00 738.30 0.00 738.30 0.00 0.00 1598.30

Total 1242.00 60.00 1208.50 142.74 1411.24 0.00 256.67 2909.91

Source: CEA website



161133-40ER-0007-00 3-7

Table 3-9: Actual Power Supply Position in North-Eastern Region

Period

Peak Demand

(MW)

Peak Met

(MW)

Peak Deficit/ Surplus

(MW)

Peak Deficit/ Surplus

(%)

Energy Require-

ment (MU)

Energy Availa- bility (MU)

Energy Deficit/ Surplus

(MU)

Energy Deficit/

Surplus(%)

9th Plan end 1148 1403 -105 -9.1 5935 5855 -80 -1.3

2002-03 1209 1135 -74 -6.1 6350 6195 -155 -2.4

2003-04 1259 1071 -188 -14.9 6640 6288 -352 -5.3

2004-05 1272 1128 -144 -11.3 7119 6674 -445 -6.3

2005-06 1385 1192 -193 -13.9 7534 6888 -646 -8.6

2006-07 1477 1166 -311 -21.1 7782 7012 -770 -9.9

2007-08 1742 1347 -395 -22.7 8799 7713 -1086 -12.3

2008-09 1820 1358 -462 -25.4 9407 8134 -1273 -13.5

2009-10 1760 1445 -315 -17.9 9332 8296 -1036 -11.1

2010-11 1913 1560 -353 -18.5 9861 8992 -869 -8.8

2011-12 1920 1782 -138 -7.2 11011 9964 -1047 -9.5

2012-13 1998 1864 -134 -6.7 11566 10718 -848 -7.3

2013-14 2164 2048 -116 -5.4 12687 11866 -821 -6.5

April 2014 – May 2014

2197 2045 -152 -6.9 11660 10914 -746 -6.4

Source: CEA Website

Likely addition of power from different resources in the region is as follows:

Table 3-10: Likely capacity addition during 12th Plan (2012-17) in North-Eastern Region

(Figures in MW)

State Hydro (MW) Thermal (MW) Total

(MW) Coal Gas Total Nuclear

Ar. Pradesh 2710 0 0 0 0 2710

Assam 0 250 100 350 0 350

Manipur 0 0 0 0 0 0

Meghalaya 40 0 0 0 0 40

Mizoram 60 0 0 0 0 60

Tripura 0 0 826 826 0 826

Sikkim 1367 0 0 0 0 1367

Total (NER) 2810 250 926 1176 0 3986

Source: Report of “The Working Group on Power for Twelfth Plan (2012-17)”, Ministry of Power, GoI



161133-40ER-0007-00 3-8

3.7 Hydropower Potential of Arunachal Pradesh

The topography of the state provides very ideal conditions for developing hydroelectric

projects. There are five major river basins in the state, namely Kameng, Subansiri, Siang,

Dibang and Lohit. There are also many smaller river systems in the state which offer very

attractive sites for hydroelectric projects. Almost all the major river systems flow in the

north-south direction and ultimately drain into the Brahmaputra. Apart from the major rivers,

the state has many small perennial rivulets providing ideal conditions for developing

micro/mini and small hydroelectric projects.

As per the preliminary ranking study done by the Central Electricity Authority (CEA), the total

power potential from hydro projects in the north-eastern region is estimated to be about

58,971 MW, of which 50328 MW is in Arunachal Pradesh

3.8 Power Situation in Arunachal Pradesh

Despite availability of such huge potential, the state has so far developed only 405 MW

under the state sector from various micro/mini/small hydroelectric projects, as on May 31,

2014. Other projects, Kameng HEP, Subansiri Lower HEP and Pare HEP with installed

capacities of 600 MW, 2000 MW and 110 MW, respectively, are under construction and

likely to be completed during the 12th Plan period. During the year 2012-13, energy

requirement in Arunachal Pradesh was 552 MU out of which 517 MU was met and

peak demand was 125 MW out of which 124 MW was met.

Table 3-11: Likely capacity addition (Hydro) during 12th Plan (2012-17) in Arunachal Pradesh

Project Name Installed Capacity Capacity addition Share of the State

Kameng 600 MW 600 MW 105.37 MW

Subansiri Lower 2000 MW 2000 MW 281.90 MW

Pare 110 MW 110 MW

Total 2710 MW 2710 MW 387.27 MW

Source: CEA Website

3.9 Development of Hydropower Demand

3.9.1 Present Status

A target of 78,700 MW was set to be achieved by the end of 11th five year plan but, only

54,964 MW could be added by the end of 11th five year plan registering a shortfall of over



161133-40ER-0007-00 3-9

30%. In hydro segment, only 67% of the target could be achieved but, that is predominantly

on account of clearing the backlog arising due to projects slipping from 10th five year plan or

even before. The present hydropower installed capacity as on May 31, 2014 is

approximately 40,661.41 MW which is about 16.5% of total electricity generation in India.

The plan-wise growth of hydropower in India is given below in Table 3-12.

Table 3-12: Plan-wise Growth of Hydropower

Plan Period Hydro Capacity Addition during the Plan (MW)

Installed Capacity* at the end of Plan (MW)

Hydropower share as % of Total Installed

Capacity Hydro Total including

other R.E.S.

1st Plan (1951-56) 380.19 1061.44 2886.14 36.78

2nd Plan (1956-61) 977.18 1916.66 4653.05 41.19

3rd Plan (1961-66) 2207.08 4123.74 9027.02 45.68

3 Annual Plan (1966-69) 1783.17 5906.91 12957.27 45.58

4th Plan (1969-74) 1058.39 6965.30 16663.56 41.80

5th Plan (1974-79) 3867.77 10833.07 26680.06 40.60

Annual Plan (1979-80) 550.90 11383.97 28447.83 40.01

6th Plan (1980-85) 3076.05 14460.02 42584.72 33.93

7th Plan (1985-90) 3828.41 18307.63 63636.34 28.77

2 Annual Plans (1991-92) 881.50 19194.62 69065.39 27.79

8th Plan (1992-97) 2427.65 21644.80 85019.31 25.46

9th Plan (1997-02) 4538.25 26261.23 103410.04 24.40

10th Plan (2002-07) 7886.00 34653.77 132329.21 26.19

11th Plan (2007-12) 5544.00 38990.40 199877.03 19.51

12th Plan (2012-17) (as on May 31, 2014)

1671.01 40661.41 248509.63 16.36

* Does not include hydro projects having capacity upto 25MW

Source: CEA Website

3.9.2 Forecast

The 18th Electric Power Survey (EPS) of India undertaken by Central Electricity Authority has

assessed the demand of power by the end of 12th Five Year Plan, that is, 2016-17 as

1354.8 Billion Units (BU) of electric energy and Annual Peak Electric Load of 199,540 MW.

To meet this demand, a total capacity addition target of 88,537 MW has been fixed



161133-40ER-0007-00 3-10

from conventional sources for the 12th Plan comprising of Hydro - 10,897 MW,

Thermal - 72,340 MW and Nuclear - 5,300 MW. In addition, the capacity addition target from

Renewable Energy Sources (RES) is 30,000 MW.

Considering the fact that the Compounded Annual Growth Rate (CAGR) of generation

during the 11th Plan period was around 8.5%, the power sector has to gear up for long term

capacity addition and steps need to be taken to exploit the identified potential at an

accelerated pace commensurate with the growing demand.

3.9.3 Long Term Plan

As per the re-assessment of the hydro electric potential carried out by CEA, the hydro

potential of the country has been estimated about 150,000 MW. The hydro installed capacity

at the end of 11th plan (2007-12) was 38990.40 MW. Anticipated hydro capacity addition

during 12th plan and 13th plan is projected below:

12th plan (2012-17) 10,897 MW

13th plan (2017-22) 12,000 MW

3.10 Necessity and Justification for Implementing the Project

The state plans to harness its enormous natural resource of hydro power and exploit its

mineral wealth to usher in an era of economic development and raise the per capita

electricity consumption.

Comparing the projected growth of peak power demand, energy requirement anticipated and

increase in the generating capacity on the basis of new projects proposed and/or under

construction/consideration during 12th Five Year Plan, it is evident that there is a dire need to

provide additional power to the National Grid. New schemes have to be taken up

immediately and implemented to derive timely benefits. The most important source of power

development in the north-eastern region is Arunachal Pradesh and other sister states.

The power from hydro projects in the north-eastern region would be in excess of the demand

in the region and would have to be exported for utilization in other regions of the country.

Presently there is no problem in the availability of transmission systems beyond the

north-eastern power region for distribution of power as the five power regions of the country

are in the process of greater integration within a national grid.



161133-40ER-0007-00 3-11

Considering the growth of peak demand and anticipated addition of generating capacity in

the state, the region and the country, and also from the current status of development of

hydro power potential of Arunachal Pradesh, it is pragmatic that earnest efforts are made for

developing the hydro power sector of the state. Thus implementing Par Hydroelectric Project

of 52 MW capacity will not only support the Power requirement of Northeast but also can

export excess power to other states and earn additional revenue for the state.



161133-40ER-0007-00

CHAPTER - 4 Data Collection and Field Investigation



161133-40ER-0007-00 i

TABLE OF CONTENTS

PAGE NO.

4 DATA COLLECTION AND FIELD INVESTIGATION .............................................. 4-1

4.1 General ......................................................................................................... 4-1

4.2 Data Collection ............................................................................................. 4-1

4.3 Field Investigations ....................................................................................... 4-2

4.4 Topographic Surveys ................................................................................... 4-2

4.4.1 Available Data ................................................................................... 4-2

4.5 Reconnaissance and Alternative Studies ..................................................... 4-3

4.6 Equipments Used ......................................................................................... 4-3

4.7 Detailed Survey and Methodology ............................................................... 4-3

4.8 General Layout Survey ................................................................................. 4-3

4.8.1 Headworks Area ............................................................................... 4-3

4.8.2 Water Conductor System .................................................................. 4-4

4.8.3 Powerhouse Site ............................................................................... 4-4

4.9 Geological and Geotechnical Investigations................................................. 4-5

4.9.1 Surface Geological Mapping ............................................................. 4-5

4.9.2 Sub-Surface Geological Explorations ............................................... 4-6

4.10 Laboratory Test of Rock Core Samples ....................................................... 4-8

4.11 Construction Material Survey ..................................................................... 4-12

4.12 Archaeological, Historical and Cultural Sites .............................................. 4-13

4.13 Presence of Economic Minerals ................................................................. 4-13



161133-40ER-0007-00 ii

LIST OF TABLES

PAGE NO.

Table 4-1: Survey Details ..................................................................................................... 4-4

Table 4-2: Details of Geological Mapping ............................................................................ 4-6

Table 4-3: List of Exploratory Drill holes .............................................................................. 4-6

Table 4-4: Laboratory Test Results of Core Samples .......................................................... 4-9



161133-40ER-0007-00 4-1

4 DATA COLLECTION AND FIELD INVESTIGATION

4.1 General

Data collection and field investigations constitute an important activity in the planning and

design of a hydropower project. It starts from the initial conception stage of the project and

continues during the project implementation.

Data collection usually comprises collection and compilation of:

Historical data pertaining to river discharge, rainfall, temperature, sediment content in

the river flow.

Historical data of past earthquakes in the region

Large scale topographical maps (usually from government agencies)

Satellite imagery of the project area, etc.

Field investigations normally comprise of:

Topographical surveys connected to GTS benchmark

Surface geological mapping

Sub-surface geological and geotechnical investigations through exploratory drilling

and drifting

Hydro-meteorological observations – measurement of rainfall, river discharge, etc.

Construction material survey, etc.

In addition, laboratory testing of materials also forms an important part of investigation work

related to planning of a project.

Status of the above activities at Pare project is discussed in the following sections.

4.2 Data Collection

As mentioned above, data collection is a continuous activity and starts with the initial

conception stage of the project.



161133-40ER-0007-00 4-2

At Par project, the historical data pertaining to river discharges and rainfall in the project

catchment and surrounding areas has been collected and compiled. Additional data

pertaining to hydrology are being collected and used in the assessment of hydrology of the

project.

A summary of collected data is presented in the chapter on hydrological assessment.

The data has been used to assess the water availability for power generation as well as to

obtain the magnitude of project’s design flood.

4.3 Field Investigations

Field survey and investigations were carried out with the objective of preparing grid maps,

establishing ground control points, fixing alignments and obtaining the river’s L-section,

cross sections etc.

Detailed topographical survey covering the head works area and the powerhouse complex

area was carried out for designing the project components. The river profile was mapped at

key points for assessing the power potential of the river.

Geological investigations comprising subsurface investigations, surface geological mapping

and traverse along HRT alignment were carried out after preliminary surveys. Subsurface

investigations included study of rock properties using exploratory drill holes.

All topographic survey and field investigation works have been carried out under the scope

of work of Preparation Phase of the project by SLEI.

4.4 Topographic Surveys

4.4.1 Available Data

The following topographical maps of Survey of India covering the entire project area are

available:

83 E 7 to12, Scale 1:50 000

On the basis of topographical maps, reconnaissance of the project area was done and

requirement of large scale mappings was worked out.



161133-40ER-0007-00 4-3

4.5 Reconnaissance and Alternative Studies

Before conducting survey for the project, a detailed reconnaissance of the area was carried

out, which was also utilized for search of known control stations viz. BMs and logistic

approach, if any. Reconnaissance was also carried out for the selection of diversion site,

intake, Desilting Basin, HRT, Surge Shaft, Pressure Shaft and Powerhouse on Left side of

river.

4.6 Equipments Used

The following equipments were used for fieldwork and processing:

Total Station Top Con GTS 7500 Series

(List Count 0.5 Second, Accuracy 1 Second)

: 1 no.

Total Station Top Con Japan GTS 3001 LN Series

(List Count 1 Second, Accuracy 1 Second)

: 1 no.

Total Station Top Con Japan GTS 3005 LN Series

(List Count 1 Second, Accuracy 5 Second)

: 1 no.

Auto Plotter Software : 2 nos.

Pythagoras Software : 2 nos.

4.7 Detailed Survey and Methodology

The survey work was conducted in accordance with specifications and scope of work

supplied by the SLEI using standard survey procedures.

4.8 General Layout Survey

The survey for developing the general layout of the project has been carried out covering the

river stretch area, extending about 1000m upstream of diversion site and upto 1000m

downstream of the proposed powerhouse site.

4.8.1 Headworks Area

Proposed barrage site of Par hydroelectric project on Pare River before the confluence of

Pare with Dardung nallah was selected and area was surveyed 500m upstream and 1000m



161133-40ER-0007-00 4-4

downstream of barrage axis on scale 1:1000 with contour interval of 2m on the basis of

established traverse stations BM by using total station.

4.8.2 Water Conductor System

Water conductor system includes a headrace tunnel of about 8.636km length proposed on

left bank of river, Desilting Basin, surge shaft and pressure shafts, which finally terminates to

Powerhouse. Survey for these was carried out based on known stations on scale as given in

Table 4-1.

4.8.3 Powerhouse Site

The proposed surface powerhouse has been planned on the left bank of the Pare river

terrace deposit around El 635m to 645m. Survey has done up to 200m upstream & 500m

downstream of proposed powerhouse site. The topographical maps of these areas will be

prepared to a scale of 1:1000 with a contour interval of 2m.

Table 4-1: Survey Details

Description Scale Contour interval

Detailed topographical survey of the project area (Barrage and Powerhouse area)

1:1000 2m

Detailed topographical survey of the reservoir area 1: 2000 2m

River cross sections @50m c/c from 1km upstream to 1km downstream of barrage axis

1:2000 H 1:100 V

River cross sections @50m c/c from 500m upstream and 200m downstream of tailrace outfall axis

1:2000 H 1:100 V

Longitudinal section of the river 1km upstream of barrage axis to 1km downstream of barrage axis

1:10000 H 1:100 V

Quarry / borrow areas, project roads and muck disposal area (Provisional)

1:1000 2m

Construction plant areas, labour colony 1:2000 2m

The reduced levels and co-ordinates will be transferred from the permanent trigonometric

points which are established by the Survey Department of India. All the permanent control

points will be established by either constructing concrete pillars or marking the information

on the stable boulders. Sufficient numbers of permanent survey stations will be established

near the main components of the project such as the head works, the adit portals, the surge

shaft, and the tailrace outfall.



161133-40ER-0007-00 4-5

Detailed topographic survey maps are being prepared and will include details pertaining to

physical and manmade features e.g. roads, footpaths, houses, large boulders, river/streams

etc. Some special landslide signs such as cracks; scarp areas etc. will also be surveyed.

In general, the details, which are being picked up from the field are grouped as follows:

Land topography such as peaks, depressions, saddles, spurs, big boulders etc.

Hydrographic features such as: rivers, streams, drainage patterns, ponds,

waterfalls etc.

Man-made features like houses, temples, roads, footpaths, bridges, culverts,

causeways etc.

Prominent public places

Land use patterns, such as cultivated land, forest land, open space etc.

4.9 Geological and Geotechnical Investigations

Adequate geological and geotechnical investigations have been carried out to ensure that

the project components are properly located and oriented. In addition, several tests have

been planned to carry out to obtain parameters for use in design.

4.9.1 Surface Geological Mapping

The surface geological mapping undertaken on the project site consisted of identification and

description of outcrops encountered in the project area and collection of all relevant

geological data. As far as possible all lithological contacts, geological features such as faults,

folds, shear zones etc. were noted. The surface geological mapping has been carried out in

the sites of different project appurtenants like headwork’s and powerhouse areas on

1:1000 scale. Reservoir area and HRT alignment were mapped on 1:4000 and

1:10000 scales respectively.

The project area has been located between villages Sagalee and village Ballapu. In general,

the topography around the project area is rugged and most of the area is vegetated. Project

has been conceptualized on the main river Pare, which flows from west-east direction

through a V-shaped valley in the area. Bedrock exposures are seen along the edges of river

and nallah courses at headworks area and most of the slope area is covered by slope wash

deposits that support moderate to thick vegetation. Due to rugged topography, geological

mapping along HRT route was taken up by taking traverses along the existing road and



161133-40ER-0007-00 4-6

through existing foot tracks at higher reaches. The geological mapping carried out for

different appurtenants of the project is given in Table 4-2.

Table 4-2: Details of Geological Mapping

S.No. Structure Scale

1 Diversion site including intake structure, feeder channel and desilting basin

1:1000

2 Powerhouse complex including surge shaft, pressure shaft, powerhouse and Tailrace tunnel

1:1000

3 HRT alignment 1:10000

4 Reservoir area 1:4000

4.9.2 Sub-Surface Geological Explorations

The subsurface investigations/explorations comprising exploratory drilling were carried out at

the sites of different appurtenants with a view to determine the depth of overburden and to

assess the nature of bedrocks encountered at different appurtenants of project.

Altogether, the project site was investigated through 20 numbers of drillholes. Out of which,

13 drillholes were drilled at headwroks area covering barrage site, intake area, desilting

basin area, power intakes and wing walls of diversion structure. Four numbers of holes were

drilled at powerhouse site and pressure shaft area. Three more drillholes located along

alignment of pressure shaft and surge shaft are in progress. The detailed location of

drillholes is given in Table 4-3.

Table 4-3: List of Exploratory Drill holes

S.No. Drill hole

No. Location

Co-ordinates & Ground

Elevation (m)

Total depth (m) / Bottom elevation (m)

Depth of Overburden (m) & Bedrock Elevation

(m)

Dam Site

1 DH-01 U/S of Barrage

axis

N 59629.888 E 54229.294

El 824

30 El 794

1.00 El 823

2 DH-02 Left Bank along

Barrage axis

N 59634.253 E 54258.009

El 826

30 El 796

0.45 El 825.55



161133-40ER-0007-00 4-7

S.No. Drill hole

No. Location


Elevation (m)



(m)

3 DH-03 Riverbed, along

Barrage axis

N 59616.598 E 54249.262

El 823.8

20 El 803.8

3.00 El 820.8

4 DH-04 Right bank, along

Barrage axis

N 59591.204 E 54235.282

El 825

25 El 800

1.50 El 823.5

5 DH-05 D/s of Barrage axisN 59576.932 E 54302.201

El 822

30 El 792

0.00 El 822

6 DH-06 Intake N 59641.856 E 54242.325

El 826.5

30 El 806.5

3.50 El 823

7 DH-07 Desilting Basin N 59661.670 E 54321.632

El 838

30.5 El 807.5

15.00 El 823


El 841

35.5 El 805.5

15.00 El 826

9 DH-09 HRT N 59622.100 E 54455.289

El 849.6

31 El 818.6

12.00 El 837.6


El 829

30 El 799

8.00 El 821


El 835

35 El 800

12.50 El 822.5

12 DH-13 Right Bank (Wing

Wall)

N 59590.682 E 54168.615

El 838

20 El 818

8.00 El 830

13 DH-14 Left Bank (Wing

Wall)

N 59675.727 E 54216.791

El 836

30 El 806

4.00 El 832

Powerhouse Site

1 PDH-01 Surge Shaft N 57264.236 E 61158.986 El 879.389

89 El 790.389

23.50 El 855.889



161133-40ER-0007-00 4-8

S.No. Drill hole

No. Location


Elevation (m)



(m)

2 PDH-03 Pressure Shaft N 57064.428 E 61060.365

El 755

42 El 713

21.45 El 733.55

3 PDH-04 Pressure Shaft N 56985.120 E 61017.430

El 704

35 El 669

12.00 El 692

4 PDH-05 Powerhouse

Terrace

N 56898.426 E 60996.913

El 651.7

50 El 601.7

18.00 El 633.7

5 PDH-06 Powerhouse

Terrace

N 56870.917 E 61013.003

El 644

30 El 614

9.00 El 635

6 PDH-07 Powerhouse

Terrace

N 56854.689 E 60998.328

El 640

30 El 610

6.5 El 633.5

7 PDH-08 Powerhouse

Terrace

N 56873.140 E 60966.526

El 646

30 El 616

9.5 El 636.5

4.10 Laboratory Test of Rock Core Samples

Rock core samples have been collected from drill holes and given for laboratory testing to

determine the physico-mechanical properties of rocks available in the project area.

The results of petrographic tests and laboratory tests of core samples are given in Table 4-4.



161133-40ER-0007-00 4-9

Table 4-4: Laboratory Test Results of Core Samples

Drill Hole No.

Location Depth of sampling

Rock Type UCS (Mpa) Modulus of

Elasticity (Dry) (Gpa)

Poisson's Ratio (Dry)

Porosity (%)

Water Absorption

(%)

Dry Density

(gm/cm3)

Specific Gravity Dry Saturated

DH -01 Barrage

1.0 – 2.5 Granitic Gneiss 48.783 40.77 0.24 1.31 0.51 2.739 2.62

1.5 -3.5 Granitic Gneiss 64.063 1.32 0.51 2.713 2.64

6.5- 8.0 Granitic Gneiss 103.058 0.74 0.28 2.719 2.63

8.0-9.5 Granitic Gneiss 53.602 45.81 0.23 1 0.38 2.695 2.68

11.0 – 12.5 Granitic Gneiss 42.681 1 0.38 2.541 2.64

18.5 – 20.0 Granitic Gneiss 101.783 0.91 0.34 2.659 2.68

DH -03 Barrage 9.0 – 10.5 Granitic Gneiss 38.559 36.02 0.24 1.52 0.6 2.625 2.56

18.0 – 19.5 Granitic Gneiss 64.952 55.71 0.22 1.3 0.5 2.765 2.64

DH - 04 Barrage 2.0 – 3.5 Granitic Gneiss 65.929 54.36 0.22 0.66 0.25 2.615 2.63

9.5 – 11.0 Granitic Gneiss 46.492 44.17 0.23 1.68 0.67 2.768 2.56

DH - 05 Barrage

12.5 -14.0 Granitic Gneiss 30.906 1.29 0.5 2.572 2.63

15.5 – 17.0 Granitic Gneiss 17.34 1.87 0.71 2.61 2.68

24.5 – 26.0 Granitic Gneiss 94.93 1.41 0.54 2.616 2.66

29.0 – 30.0 Granitic Gneiss 41.602 1.32 0.5 2.646 2.67

DH - 06 Barrage

9.5 – 11.0 Granitic Gneiss 48.905 1.04 0.4 2.575 2.63

14.0 – 15.5 Granitic Gneiss 64.587 0.66 0.25 2.608 2.62

14.0 - 15.5 Granitic Gneiss 76.183 1.11 0.43 2.594 2.6

17.0 – 18.5 Granitic Gneiss 114.959 1.02 0.39 2.621 2.65

18.5 – 20.0 Granitic Gneiss 79.061 1.27 0.49 2.601 2.62



161133-40ER-0007-00 4-10

Drill Hole No.





Porosity (%)

Water Absorption

(%)

Dry Density

(gm/cm3)


DH - 09 Barrage

17.0– 18.5 Granitic Gneiss 12.205 2.14 0.83 2.511 2.62

18.5 – 20.0 Granitic Gneiss 33.5 1.12 0.44 2.619 2.59

23.0- 24.5 Granitic Gneiss 24.041 1.49 0.57 2.565 2.67

23.0- 24.5 Granitic Gneiss 28.818 1.56 0.59 2.621 2.67

DH - 10 Barrage

9.5 – 11.0 Granitic Gneiss 39.604 1.84 0.7 2.642 2.69

15.5 – 17.0 Granitic Gneiss 47.92 1.51 0.58 2.631 2.62

20.0 – 21.5 Granitic Gneiss 51.183 0.87 0.34 2.591 2.61

23.0 – 24.5 Granitic Gneiss 72.146 0.77 0.29 2.618 2.63

29.0 – 30.0 Granitic Gneiss 39.93 1.31 0.5 2.648 2.66

DH - 13 Barrage

10.0 – 11.5 Granitic Gneiss 31.8 1.05 0.4 2.605 2.65

11.5 – 13.0 Granitic Gneiss 59.051 1.72 0.34 2.618 2.74

14.5 – 16.0 Granitic Gneiss 45.671 1.72 0.66 2.642 2.64

14.5 – 16.0 Granitic Gneiss 47.385 1.65 0.62 2.63 2.71

DH - 14 Barrage

5.0 – 6.5 Granitic Gneiss 19.009 1.97 0.75 2.609 2.67

11.0 – 12.5 Granitic Gneiss 19.297 1.98 0.75 2.62 2.69

17.0 – 18.5 Granitic Gneiss 36.795 0.82 0.31 2.616 2.66

26.0 – 27.5 Granitic Gneiss 40.16 0.76 0.29 2.638 2.68

29.0 – 30.0 Granitic Gneiss 29.525 0.85 0.32 2.649 2.66

PDH - 06 Powerhouse 9.0 – 10.0 Granitic Gneiss 35.419 30 0.25 1.94 0.74 2.644 2.69

15.0 – 16.50 Granitic Gneiss 35.712 31.45 0.24 1.32 0.5 2.636 2.69



161133-40ER-0007-00 4-11

Drill Hole No.





Porosity (%)

Water Absorption

(%)

Dry Density

(gm/cm3)


PDH - 07 Powerhouse

9.5 – 11.0 Granitic Gneiss 18.453 1.35 0.5 2.619 2.72

12.5 – 14.0 Granitic Gneiss 31.9 0.62 0.24 2.638 2.65

15.5 – 17.0 Granitic Gneiss 40.511 1.17 0.45 2.636 2.66

18.5 – 20.0 Granitic Gneiss 43.353 0.89 0.34 2.659 2.65

21.5 – 23.0 Granitic Gneiss 49.249 1.05 0.4 2.64 2.65



161133-40ER-0007-00 4-12

4.11 Construction Material Survey

Large quantities of material would be required for the construction of the project while most

of the material such as cement, steel, and explosives will be procured from the open market.

Coarse and fine aggregates required for making concrete will have to be sourced from the

project area preferably from sites close to the work areas. The excavated materials from

proposed project components such as diversion structures, tunnel and powerhouse area can

be used. To this end, a detailed field survey has been carried out.

Different alternative sites identified on both the banks of Pare River as well as some RBM

sites located within riverbed are described below:

Site 1: A wide Shoal deposit located around diversion site has been selected for

coarse aggregate. This quarry site is about 350m extended along the river on both

upstream and downstream of proposed diversion axis. From diversion axis upstream,

the site is extended upto about 150m and towards downstream it is extended about

200m. The average width of the shoal varies between 30 and 35m. RBM here

consists of quartzite gneiss, granite gneiss and quartzite. The size of boulders varies

between 0.25m3 to 2.5m3 but mostly <1m3.

Site 2: It is a Rock Quarry located on left bank of Pare river near diversion area.

The steep cliff of rock along river edge exists from 86m upstream of proposed

diversion axis up to Rach nallah confluence. The exposed rockmass is observed

between El 820m and El ± 840m.

Site 3: it is identified on the left bank of Pare river just at the confluence of Dardung

nallah. The extent of this rock quarry is about 110m with quartzitic gneiss rocks along

left bank of Dardung nallah. In this reach, Rock exposed from El 820m to El 840m

along the river and along the nallah from El 230m to El 240m.

Site 4: This is a Rock Quarry located on Right bank just opposite to Site 3. In this

reach, rock exposed all along the river between El 820m and El 840m.

Site 5: This is a RBM quarry located in Pare riverbed near proposed powerhouse.

This RBM deposits form an isolated hump within river, which is 157m long with

average width of 25m.



161133-40ER-0007-00 4-13

Site 6: This is a Rock Quarry located on Left bank of Pare river about 660m

upstream of powerhouse complex site. Rockmass is exposed at steep slope from El

645m to El 670m.

Site 7: This Rock Quarry is located on right bank along river Pare just opposite to

proposed powerhouse location. The exposed rock mass between El 630m and El

660m comprises quartzitic gneiss.

The total potential of these sites are more than the required quantity.

However, among these potential sites, representative samples from each site was collected

and tested in laboratory to determine its suitability as coarse and fine aggregate for

construction. The detail report of test results is appended in Appendix-B. Maps shown of

quarry area are given in Plate 13-1 to Plate 13-5 of Chapter-13 in Volume-I (Part-II)

of the DPR.

4.12 Archaeological, Historical and Cultural Sites

No sites of archeological, historical or cultural importance exist at or near the project

location.

4.13 Presence of Economic Minerals

No minerals of economic importance have been reported to be present in the project area as

per reports of GSI and any other agency.



161133-40ER-0007-00

CHAPTER - 5 Project Hydrology



161133-40ER-0007-00 i

TABLE OF CONTENTS

PAGE NO.

5 PROJECT HYDROLOGY ........................................................................................ 5-1

5.1 Introduction ................................................................................................... 5-1

5.1.1 Adopted Conventions ....................................................................... 5-1

5.2 Basin Characteristics .................................................................................... 5-2

5.2.1 River System and Basin Characteristics ........................................... 5-2

5.2.2 The Catchment ................................................................................. 5-2

5.2.3 Hypsometric Detail............................................................................ 5-2

5.2.4 Climatology ....................................................................................... 5-4

5.3 Water Availability Studies ............................................................................. 5-5

5.3.1 Data .................................................................................................. 5-5

5.3.2 Topography....................................................................................... 5-5

5.3.3 Precipitation ...................................................................................... 5-5

5.3.4 Consistency Checks of Rainfall Data ................................................ 5-6

5.3.5 Flow Series Assessment ................................................................ 5-13

5.3.6 Flow Duration Curves and Annual Dependabilities ........................ 5-20

5.4 Design Flood and Rating Curves ............................................................... 5-24

5.4.1 General ........................................................................................... 5-24

5.4.2 Approaches for Estimation of Design Flood ................................... 5-24

5.4.3 Flood Estimation by Probabilistic Approach ................................... 5-25

5.4.4 Flood Estimation by Hydro-meteorological Approach ..................... 5-30

5.4.5 Design Flood for River Diversion Works ......................................... 5-42

5.4.6 Tail Rating Curves .......................................................................... 5-47

5.5 Sedimentation Study .................................................................................. 5-52

5.5.1 Reservoir Elevation-Area-Capacity ................................................. 5-52

5.6 References ................................................................................................. 5-54



161133-40ER-0007-00 ii

LIST OF ANNEXURES AND PLATES

ANNEXURES:

Annexure 5-1: Rainfall Data

Annexure 5-2: Discharge Data of Pare Dam Site, Hoz G&D Site and Par G&D Site

Annexure 5-3: Letter of Design Storm value for Par, Turu and Dardu Hydroelectric Projects

Annexure 5-4: Convolution of unit Hydrograph with Rainfall

PLATES:

Plate 5-1: Catchment Area Map

Plate 5-2: Location Map of Hydro-meteorological Stations



161133-40ER-0007-00 iii

LIST OF TABLES

PAGE NO.

Table 5-1: Hypsometric Detail of the Catchment ................................................................. 5-2

Table 5-2: Available Maps Used for the Catchment Area Delineation ................................. 5-5

Table 5-3: Meteorological Stations ...................................................................................... 5-6

Table 5-4: Available Discharge Data ................................................................................. 5-13

Table 5-5: T-test for Homogeneity of Flow Series at Par ................................................... 5-16

Table 5-6: Flow Series at Par Project Site ......................................................................... 5-17

Table 5-7: Computation of Dependabilities of Annual Inflow ............................................. 5-21

Table 5-8: Details of Annual Peak flow at Par ................................................................... 5-26

Table 5-9: Detailed Statistics for Instantaneous Peak Flow Data ...................................... 5-27

Table 5-10: Outlier Test for Annual Peak Flow .................................................................. 5-28

Table 5-11: Return Period Flood ........................................................................................ 5-29

Table 5-12: Computation of Equivalent Slope ................................................................... 5-32

Table 5-13: Unit Hydrograph Parameters .......................................................................... 5-34

Table 5-14: Temporal Distribution of 24-hour Design Storm ............................................. 5-35

Table 5-15: Distribution of 24-hour Design Storm .............................................................. 5-36

Table 5-16: Rainfall Excesses for 50-Year Return Period ................................................. 5-37

Table 5-17: Rainfall Excesses for 100-Year Return Period ............................................... 5-37

Table 5-18: Rainfall Excesses for SPF .............................................................................. 5-38

Table 5-19: Critical Sequencing of Rainfall Excess ........................................................... 5-38

Table 5-20: 50 and 100-Year Return Period flood and SPF Hydrograph Values .............. 5-41

Table 5-21: Summary of Project Design Flood .................................................................. 5-42

Table 5-22: Details of Non-Monsoon Flood Peaks at Par .................................................. 5-43

Table 5-23: Detailed Statistics ........................................................................................... 5-44

Table 5-24: Outlier Test for Annual Peak Flow .................................................................. 5-45

Table 5-25: 25 Year Non-Monsoon Return Period Flood at Hoz ....................................... 5-46

Table 5-26: Stage Discharge Computation at 50m Downstream of Barrage Axis ............. 5-48

Table 5-27: Stage Discharge Computation at 100m Downstream of Barrage Axis ........... 5-49

Table 5-28: Stage Discharge Computation at Tailrace Location ....................................... 5-51

Table 5-29: Area-Capacity Value ....................................................................................... 5-53



161133-40ER-0007-00 iv

LIST OF FIGURES

PAGE NO.

Figure 5-1: Hypsometric Curve of the Project Catchment ................................................... 5-3

Figure 5-2: Mass Curves of Rainfall data ............................................................................. 5-7

Figure 5-3: Double Mass Curves of Rainfall data between Leporiang and Sagalee............ 5-8

Figure 5-4: Double Mass Curves of Rainfall data between Leporiang and Loplop .............. 5-8

Figure 5-5: Double Mass Curves of Rainfall data between Loplop and Sagalee ................. 5-9

Figure 5-6: Double Mass Curves of Rainfall data between Jampa and Leporiang .............. 5-9

Figure 5-7: Double Mass Curves of Rainfall data between Jampa and Loplop ................. 5-10

Figure 5-8: Double Mass Curves of Rainfall data between Jampa and Sagalee ............... 5-10

Figure 5-9: Plot of Monthly Rainfall at Raingauge Stations ............................................... 5-11

Figure 5-10: Average Annual Rainfall Pattern at Raingauge Stations ............................... 5-12

Figure 5-11: Average Annual Rainfall Pattern at Raingauge Stations ............................... 5-12

Figure 5-12: Mass Curve of Observed Discharge at Par ................................................... 5-14

Figure 5-13: Flow Duration Curve at Par Diversion Site for All 30 years series ................. 5-22

Figure 5-14: Flow Duration Curve of 90% Dependable Year ............................................. 5-22



Figure 5-17: Flow Duration Curve of Observed Data at Par G & D Site ............................ 5-24

Figure 5-18: Plot of Flood Frequency Analysis .................................................................. 5-30

Figure 5-19: L-Section of Par Catchment .......................................................................... 5-31

Figure 5-20: Parameters of SUH ....................................................................................... 5-33

Figure 5-21: SUH of Par Catchment .................................................................................. 5-34

Figure 5-22: 50-Year Return Period Flood Hydrograph ..................................................... 5-39

Figure 5-23: 100-Year Return Period Flood Hydrograph ................................................... 5-40

Figure 5-24: Standard Project Flood Hydrograph .............................................................. 5-40

Figure 5-25: Plot of Non-Monsoon Flood Frequency Analysis .......................................... 5-47

Figure 5-26: Stage Discharge Curve at 50m Downstream of Barrage Axis ....................... 5-49

Figure 5-27: Stage Discharge Curve at 100m Downstream of Barrage Axis ..................... 5-50

Figure 5-28: Stage Discharge Curve at Tailrace Channel Location ................................... 5-51

Figure 5-29: Elevation-Area-Capacity Curve ..................................................................... 5-53



161133-40ER-0007-00 5-1

5 PROJECT HYDROLOGY

5.1 Introduction

Hydrological inputs play a vital role in planning, execution and operation of any water

resources development project. Hydrological studies are carried out at all stages of project

development starting from the pre-feasibility stage and are continued even during the

operation of the project. Hydrological studies for a river valley projects are carried out with a

view to:

Assess quantity of available water in the river for power generation and its variation

with time.

Estimate design flood and diversion flood required for hydraulic design of spillway

and temporary diversion structure as well as for safety of the structure.

Sedimentation studies also usually form a part of hydrological studies in a hydro project.

However, as discussed subsequently, their relevance at the project is insignificant given that

it is being developed as a run-of-the-river scheme with Barrage as diversion structure.

Par Hydroelectric project is located on Pare River in Papum Pare District of Arunachal

Pradesh. The catchment area map of the project is shown in Plate 5-1.

As per the project planning based on detailed reconnaissance of site and assessment of

topographic and geological features, the project envisages construction of a 26.5m high

diversion structure from riverbed.

5.1.1 Adopted Conventions

The following conventions have been adopted for the hydrological calculations carried out:

The hydrological year runs from June to May of the following calendar year;

The monsoon season is defined from June to September;

The non-monsoon season is defined from October to May of the following calendar year.



161133-40ER-0007-00 5-2

5.2 Basin Characteristics

5.2.1 River System and Basin Characteristics

Pare River originates at elevation of about 2860m as Pare Nadi in the Lower Subansiri

District. After flowing for about 25km from north to south, the pare takes an eastward turn

and flows for about 43km upto Sekhi. On the way, it passes through Sagali. The main

tributaries of the Pare river are Pang and Nimte coming down from the nearby hillock.

After Confluence of Kheel Wadi with Pare on the right bank, the river assumes the name of

Dikrong/Pare. The Par, Nirochi and Pachin rivers form the Dikrong river. It flows from the

west to the southeast, and passing through Itanagar region and merges with Brahmaputra in

the Lakhimpur district of Assam.

5.2.2 The Catchment

The catchment area at the proposed diversion site of the project is 420km2. A plan of the

catchment area map is shown in Plate 5-1. The length of the Pare river up to the proposed

diversion structure is estimated as around 45.98km. All the catchment area of the project lies

below the elevation of 3000m and hence it is expected that there is no snowbound area in

the region.

5.2.3 Hypsometric Detail

A hypsometric curve is an empirical cumulative distribution function of elevations in a

catchment. It is shown as a continuous function and graphically displayed as an x-y plot, with

elevation on the vertical or y-axis and area above the corresponding elevation on the

horizontal or x-axis. For the present project the catchment areas vis-à-vis elevation has been

worked out which is given in Table 5-1 below:

Table 5-1: Hypsometric Detail of the Catchment

Elevation (m)

Area below (km2)

Area above (km2)

Area above (Percentage)

800 0 420.0 100.00%

900 1.555 418.4 99.63%

1000 9.53 410.5 97.73%

1100 24.03 396.0 94.28%

1200 45.94 374.1 89.06%

1300 74.29 345.7 82.31%



161133-40ER-0007-00 5-3

Elevation (m)

Area below (km2)

Area above (km2)

Area above (Percentage)

1400 115.78 304.2 72.43%

1500 161.85 258.2 61.46%

1600 203.9 216.1 51.45%

1700 241.13 178.9 42.59%

1800 275.94 144.1 34.30%

1900 313.44 106.6 25.37%

2000 347.86 72.1 17.18%

2100 369.77 50.2 11.96%

2200 394.04 26.0 6.18%

2300 400.65 19.4 4.61%

2400 407.81 12.2 2.90%

2500 412.34 7.7 1.82%

2600 416.99 3.0 0.72%

2700 418.41 1.6 0.38%

2860 420 0.0 0.00%

The hypsometric curve is given in the Figure 5-1 below:

HYPSOMETRIC CURVE OF PAR

500

750

1000

1250

1500

1750

2000

2250

2500

2750

3000

0 50 100 150 200 250 300 350 400 450Area above Elevation (km2)

Ele

vati

on

(m

)

Figure 5-1: Hypsometric Curve of the Project Catchment



161133-40ER-0007-00 5-4

From hypsometric detail, it can be seen that the catchment originates at an elevation of

about 2860m. The mean and median elevation of the catchment is around 1800m.

5.2.4 Climatology

The climate of the River Basin may be described as tropical monsoon climate.

The southwest monsoon normally enters Northeastern India around the end of May.

It establishes firmly over the entire region by the end of June and withdraws in the second

week of October.

During the monsoon months, different low-pressure systems like depressions, cyclonic

storms, etc. originate in the Bay of Bengal. After they cross the Indian coast, several of those

systems move in an easterly to north-easterly direction causing heavy rainfall over the Basin.

Over the year four different seasons can be defined:

Pre-monsoon (March-May);

Monsoon (June-September);

Post-monsoon (October-November);

Winter season (December-February).

Pre-monsoon

In the region of the East-Himalaya the first pre-monsoon precipitation sets in at the end of

March, mostly in form of thunderstorms. The months of April and May are characterized with

thundershowers.

Monsoon

The onset of the monsoon in northeast India happens normally between the 30th of May and

the 5th of June. This happens when the southern trade winds cross the equator and move

towards the extreme low-pressure region in Northern India.

Post-monsoon

In September the influence of the monsoon begins to decrease. In northern India a

withdrawal of the monsoon-troughs sets in suddenly and the weather becomes clearer.

During the post-monsoon season the temperature and the precipitation decline noticeably.

This time of the year is generally the most pleasant season due to the stable weather



161133-40ER-0007-00 5-5

condition and the warm climate. In the morning the valleys are filled with dense fog, but in

higher reaches the sky is clear.

Winter season

In the northeast Indian mountain range the winter is severe and characterized by low

temperature, but without significant snowfall. Precipitation only occurs in conjunction with

western disturbances (flat low-pressure areas). Starting February the temperature begins to

rise slowly again.

5.3 Water Availability Studies

5.3.1 Data

Data relevant to the project and their analysis has been provided in the subsequent

paragraphs below.

5.3.2 Topography

A detailed set of maps relevant to the project site has been made available by the project

authority which has been used for the delineation of catchment area. The parameters of the

supplied maps have been given in Table 5-2.

Table 5-2: Available Maps Used for the Catchment Area Delineation

Origin Reference Number

Longitude Latitude Scale Contour

lines

SOI 83 E/03 93°00’ – 93°15’ 27°15’ – 27°30’ 1:50,000 40m

SOI 83 E/04 93°00’ – 93°15’ 27°00’ – 27°15’ 1:50,000 40m

SOI 83 E/07 93°15’ – 93°30’ 27°15’ – 27°30’ 1:50,000 40m

SOI 83 E/08 93°15’ – 93°30’ 27°00’ – 27°15’ 1:50,000 40m

SOI 83 E/11 93°30’ – 93°45’ 27°15’ – 27°30’ 1:50,000 40m

SOI 83 E/12 93°30’ – 93°45’ 27°00’ – 27°15’ 1:50,000 40m

5.3.3 Precipitation

Available meteorological data relevant to hydrological assessment of the project are shown

in Table 5-3.



161133-40ER-0007-00 5-6

Table 5-3: Meteorological Stations

S.No. Station Type of Data Period of Availability Name of the River Basin/Catchment

1 Leporiang Daily Aug 2001-Mar 2005 Pare

2 Loplop Daily Aug 2001-Sep 2004 Pare

3 Sagalee Daily Aug 2001-Mar 2005 Pare

4 Jampa Daily Nov 2001-Feb 2005 Pare

The rainfall data has been given in Annexure 5-1. There are also availability of rainfall data

for Doimukh and Itanagar raingauge stations. However, these data (Doimukh and Itanagar)

are not in the vicinity of the project catchment and hence the data of these stations are not

analyzed further. The location of hydro-meteorological stations has been shown in Plate 5-2.

5.3.4 Consistency Checks of Rainfall Data

The calculations on water availability and flood magnitude will lead to selecting the design

features of the project (installed capacity, turbine flow, spillway capacity, etc.).

These features will directly reflect on the project cost and on the quantity and value of

energy produced. It is therefore necessary to confirm the validity of the basic data used in

the calculations. The consistency Checks of the rainfall data has been carried as follows.

A. Mass Curve of Rainfall Data

Mass curves representing the cumulated values of a hydrologic parameter like discharge or

rainfall, plotted against time, are important tools in identifying any unexplained trends in the

variable. However, since hydrologic variables show a considerable year to year variation,

this method is useful only where data for a considerable length, say exceeding 5 years, is

available. Attempt has been made to check the consistency with the available data.

In the present study, mass curves have been prepared for rainfall data available at

Leporiang, Loplop, Sagalee and Jampa.

These mass curves are shown below:



161133-40ER-0007-00 5-7

Mass Curves of Rainfall Data

0

2000

4000

6000

8000

10000

12000

J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M

2001 2002 2003 2004 2005

Cu

mu

lati

ve

of

Ra

infa

ll (

mm

)

Leporiang

Loplop

Sagalee

Jampa

Figure 5-2: Mass Curves of Rainfall data

It is seen from the mass curve as developed in the above Figure 5-2 that the month of Jun

to Sep yields a comparatively more rainfall than that of the other months in all of the stations.

This suggests that the months of from Jun to Sep are monsoon months. Apart from the mass

curve based on monthly rainfall, mass curves are also plotted based on the annual data.

B. Double Mass Curve of Rainfall Data

Double mass curve is a simple technique to examine the consistency of hydrology related

series of two different sites. For the common period, preferably around 10 years or more, the

cumulated variable (such as the rain, the flow volume) at one station is plotted against that of

the other. If the plot follows a near straight line, it indicates a consistency; if the plot has

kinks or shifts, it indicates likely inconsistencies. However, it does not indicate which data

series is inconsistent.

If data is available at a number of different stations, the inconsistent data can be located by

plotting the double mass curve in different pairs. The inconsistent data can be: a) wholly

rejected, b) rejected only for the inconsistent part, or, c) the inconsistent part may be

corrected to make it consistent, and accepted.

For the present project, the double mass curves for the raingauge stations where concurrent

data is available are plotted. To carry out a meaningful comparison with the double mass

curve technique based on the available data, the following assumptions were made:



161133-40ER-0007-00 5-8

Data was plotted on monthly basis;

When a gap exists, the data cumulative is maintained over the gap, leaving a small

space with a slope equivalent to the general slope of the curve.

The double mass curves as plotted are shown in Figure 5-3 to Figure 5-8 below:

Double Mass Curve Between Leporiang and Sagalee

0

2000

4000

6000

8000

10000

12000

0 2000 4000 6000 8000 10000 12000Cum. of Rainfall at Leporiang (mm)

Cu

m. o

f R

ain

fall

at

Sa

ga

lee

(mm

)

Figure 5-3: Double Mass Curves of Rainfall data between Leporiang and Sagalee

Double Mass Curve Between Leporiang and Loplop

0

2000

4000

6000

8000

10000

12000

0 2000 4000 6000 8000 10000 12000Cum. of Rainfall at Leporiang (mm)

Cu

m. o

f R

ain

fall

at

Lo

plo

p (

mm

)

Figure 5-4: Double Mass Curves of Rainfall data between Leporiang and Loplop



161133-40ER-0007-00 5-9

Double Mass Curve Between Loplop and Sagalee

0

2000

4000

6000

8000

10000

12000

0 2000 4000 6000 8000 10000 12000Cum. of Rainfall at Loplop (mm)

Cu

m. o

f R

ain

fall

at

Sa

ga

lee

(mm

)

Figure 5-5: Double Mass Curves of Rainfall data between Loplop and Sagalee

Double Mass Curve Between Jampa and Leporiang

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000Cum. of Rainfall at Jampa (mm)

Cu

m. o

f R

ain

fall

at

Le

po

ria

ng

(m

m)

Figure 5-6: Double Mass Curves of Rainfall data between Jampa and Leporiang



161133-40ER-0007-00 5-10

Double Mass Curve Between Jampa and Loplop

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000


Cu

m. o

f R

ain

fall

at

Lo

plo

p (

mm

)

Figure 5-7: Double Mass Curves of Rainfall data between Jampa and Loplop

Double Mass Curve Between Jampa and Sagalee

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000


Cu

m. o

f R

ain

fall

at

Sa

ga

lee

(m

m)

Figure 5-8: Double Mass Curves of Rainfall data between Jampa and Sagalee

It is observed from the above double mass curves that there is considerable consistency

among rainfall data of raingauge stations.

C. Monthly Plot of Rainfall Data

The plot of monthly rainfall at the available raingauge stations has been given in Figure 5-9

below.



161133-40ER-0007-00 5-11

Comparison of Monthly Rainfall

0

100

200

300

400

500

600

700

800J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A S O N D

2001 2002 2003 2004 2005

Mo

nth

ly R

ain

fall

(mm

)

LEPORIANG

LOPLOP

SAGALEE

JAMPA

Figure 5-9: Plot of Monthly Rainfall at Raingauge Stations

From the above figure, it can be seen that the pattern of rainfall in different months at all the

raingauge stations are almost similar. Therefore, it can be concluded that the behavior of

rainfall throughout the catchment is same.

D. Average Annual Rainfall Pattern of Raingauge Stations

The plot of average monthly rainfall pattern at different raingauge stations has been shown

in Figure 5-10. The figure indicates that the average rainfall patterns at all the raingauge

sites are almost similar. The plot of average annual rainfall at these raingauge sites is also

given in Figure 5-11 which indicates that the station at Sagalee experiences less rainfall

compared to the others.



161133-40ER-0007-00 5-12

Average Annual Rainfall Pattern of Raingauge Stations

0%

5%

10%

15%

20%

25%

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Per

cen

tag

e o

f A

vera

ge

An

nu

al R

ain

fall

(%

) Leporiang

Loplop

Sagalee

Jampa

Figure 5-10: Average Annual Rainfall Pattern at Raingauge Stations

Average Annual Rainfall of Raingauge Stations

30692870

2439

3074

0

500

1000

1500

2000

2500

3000

3500

Leporiang Loplop Sagalee Jampa

Ave

rag

e A

nn

ual

Rai

nfa

ll (

mm

)

Figure 5-11: Average Annual Rainfall Pattern at Raingauge Stations

Based on the available rainfall data, the average annual rainfall of the catchment has been

estimated to 2863mm.

E. Conclusion of Rainfall Data Analysis

Based on the analysis of available data of 4 raingauge stations in and around the vicinity of

the project, the following conclusions can be drawn:



161133-40ER-0007-00 5-13

The analysis shows that the average annual rainfall of the catchment is of the order

of 2863mm considering the all four raingauge stations. However, considering only the

raingauge stations inside the proposed project catchment, it has been estimated to

about 2655mm.

All four raingauge stations are distributed reasonably from the Pare dam site to the

proposed project at Par as can be seen from Plate 5-2.

Similar rainfall pattern has been observed in all the four raingauge stations as given

in Figure 5-9 and Figure 5-10 indicating similar basin characteristics throughout the

basin from pare dam site to the proposed project site at Par. A comparatively less

rainfall is observed at Sagalee from the other available stations. However, a strong

conclusion whether this raingauge station receives a less rainfall or not can’t be

made because the analysis is based on a very limited period of data of about 3 years

only.

Nonetheless, it can be concluded from the overall analysis that the basin

characteristics along the basin from Pare dam site to the proposed site are similar.

5.3.5 Flow Series Assessment

A. Data Available

Data available to assess the flow series of the project are given in Table 5-4.

Table 5-4: Available Discharge Data

Station Period of

Availability Name of theRiver Basin

Catchment Area (km2)

Remarks

PareDam Site 1978-79 to 2004-05 Pare 824 CWC Approved

10-Daily Average

Hoz G&D Site Apr 2005-Sep 2008 Pare 803.35 Daily

Par Project Site Nov 2011- Oct 2013 Pare 420 Daily

All the available discharge data as listed in the table above has been given in Annexure 5-2.

From the table it can be seen that, site specific observed discharge data at the proposed

project site is available from the period from Nov-2011 to Oct-2013 only, thus completing

only one year of water year data from June-2012 to May-2012.



161133-40ER-0007-00 5-14

A mass curve has been prepared to check the internal consistency of the available data at

Par which is given in Figure 5-12. The figure shows that there is a increase of discharge

from the month of May onwards to the month of September and then it recedes. However a

strong conclusion can’t be made on this as the available data is for a period of one complete

water year only. Further, no external consistency checks of the available data at the project

site could be performed because of lack of concurrent period of discharge or rainfall data.

Hence, it is felt prudent not to use this data at present in the water availability study of the

project. However, it is advisable to continue the observation of the discharge measurement

at the project site to review the water availability when sufficient data becomes available.

Mass Curve of Monthly Average Observed Discharge at Par

0

100

200

300

400

500

600

700

800

JUN

JUL

AU

GS

EP

OC

TN

OV

DE

CJA

NF

EB

MA

RA

PR

MA

YJU

NJU

LA

UG

SE

PO

CT

NO

VD

EC

JAN

FE

BM

AR

AP

RM

AY

JUN

JUL

AU

GS

EP

OC

TN

OV

DE

CJA

NF

EB

MA

RA

PR

MA

Y

2011-12 2012-13 2013-14

Cu

m. o

f M

on

thly

Ave

rag

e F

low

(m

3/s

)

Figure 5-12: Mass Curve of Observed Discharge at Par

B. Flow Series Computation

From the available discharge data, it is seen that long-term discharge data is available only

at the pare dam site which is downstream of the proposed project of Par for the period from

1978-79 to 2004-05. Hence, it has been proposed to use this data for the formulation of flow

series at the proposed project site of Par hydroelectric project. Rainfall analysis presented

previously shows that there is no variation in the basin behaviour along the basin from Pare

dam site to the Par project site. Hence, it has been proposed to transpose the flow series of

Pare dam site to the Par hydroelectric project by catchment area proportion. The formula for

deriving the flow series at Par from Pare is as follows:



161133-40ER-0007-00 5-15

Pare

ParParePar CA

CAQQ *

= ParePare QQ *51.0*824

420

Again observed discharge data at Hoz G&D site (CA = 803.35km2) is available from Apr

2005 to Sep 2008 completing 3 hydrological water year from 2005-06 to 2007-08. Hence,

this data is also transferred to the proposed project site by catchment area proportion

forming a complete series of 1978-79 to 2007-08. The formula for deriving the flow series at

Par from Hoz G&D site is as follows:

Hoz

ParHozPar CA

CAQQ *

= HozHoz QQ *52.0*35.803

420

However, the suitability of extending the flow series (i.e., homogeneity of the series derived

from two different sites) from 2005-06 to 2007-08 has been tested through t-test statistics as

follows:



161133-40ER-0007-00 5-16

Table 5-5: T-test for Homogeneity of Flow Series at Par

PeriodInflow (MCM)

1978-79 to2004-05

2005-06 to2007-08

1978-79 671 786.39504 627.6461

1979-80 686 32569.467 16292.172

1980-81 505 27 3

1981-82 456 0

1982-83 529 3

1983-84 605 1.9486099

1984-85 673 0.0732363

1985-86 941 2.3533634

1986-87 1076 0.1464727

1987-88 1282 3.1824463

1988-89 891

1989-90 830

1990-91 779

1991-92 779

1992-93 647

1993-94 783

1994-95 777

1995-96 943

1996-97 902

1997-98 871

1998-99 920

1999-00 875

2000-01 669

2001-02 896

2002-03 904

2003-04 675

2004-05 665

2005-06 649

2006-07 491

2007-08 743

t Critical one-tail

P(T<=t) two-tail

t Critical two-tail

Result: From the analysis it can be seen that the criticalvalue of “t” is greater than the calculated “t”. Hence, it isconcluded that the series derived from two sources arehomogeneous to each other.

De

riv

ed

Fro

m P

are

Da

m S

ite

De

riv

ed

Fro

m

Ho

z G

&D

Parameter

Mean

Variance

Observations

Hypothesized Mean Difference

df

t Stat

P(T<=t) one-tail

Thus the complete 10-daily average flow series for 30 years (1978-79 to 2007-08) as derived

for Par hydroelectric project has been given in Table 5-6. The average annual inflow and

average annual runoff depth of the flow series has been computed to 770.5 MCM and

1835mm respectively.



161133-40ER-0007-00 5-17

Table 5-6: Flow Series at Par Project Site

1978-79 1979-80 1980-81 1981-82 1982-83 1983-84 1984-85 1985-86

I 28.06 7.17 21.22 11.00 18.52 19.51 12.80 40.32II 43.36 26.13 43.17 11.77 49.43 34.31 33.60 34.24III 89.30 26.95 32.22 19.18 69.51 28.33 27.66 27.22I 52.47 103.30 28.39 27.20 20.59 44.61 36.41 127.41II 41.69 38.36 48.29 46.08 18.94 18.55 27.76 38.94III 36.81 39.87 19.77 23.70 31.25 25.90 43.39 60.14I 33.94 22.56 26.13 22.26 15.32 14.95 18.80 28.89II 36.71 22.17 31.54 27.73 12.73 14.25 19.39 19.35III 26.06 37.32 20.23 24.79 14.35 24.04 33.03 33.53I 28.57 52.66 13.94 18.52 11.66 24.75 39.75 33.48II 45.81 38.58 13.48 19.79 37.87 62.24 123.49 19.33III 36.35 18.74 18.80 15.37 28.04 30.29 28.60 25.89I 28.43 39.52 10.61 15.35 12.43 15.58 18.33 17.78II 21.61 21.56 8.89 10.88 10.54 35.97 20.92 36.58III 15.15 13.89 11.00 10.88 12.31 17.48 18.01 32.85I 17.36 11.29 16.17 9.90 9.57 12.34 11.82 26.80II 14.57 11.48 14.74 9.18 9.30 11.25 10.95 23.63III 17.90 12.97 10.01 8.77 8.79 10.08 9.98 21.51I 10.01 13.26 9.69 8.55 8.67 9.55 9.63 20.26II 8.31 10.68 9.44 11.41 8.94 9.08 10.00 19.76III 8.45 11.46 10.12 9.39 9.57 10.62 10.05 21.35I 7.09 10.15 9.64 8.50 8.21 8.81 9.19 18.97II 6.68 9.98 8.91 8.55 8.01 9.15 8.94 18.32III 7.53 11.56 9.96 9.18 9.18 10.08 9.55 19.56I 7.48 10.03 8.89 8.43 7.87 8.63 8.86 18.64II 6.51 10.18 8.77 9.81 7.70 8.49 8.93 18.06III 5.15 9.37 7.36 6.73 6.44 7.50 9.26 14.20I 6.27 13.28 8.69 8.98 7.70 9.41 13.14 17.37II 6.22 10.90 10.64 8.72 8.84 13.90 7.87 21.33III 6.85 10.81 11.24 10.42 9.66 11.63 11.31 18.38I 7.79 10.81 12.41 13.84 8.91 16.28 12.06 17.52II 7.28 11.31 12.14 14.35 9.88 13.19 14.72 31.83III 8.64 27.68 10.15 14.91 15.35 11.01 13.26 35.56I 15.64 19.47 11.10 15.20 34.86 12.20 21.34 42.05II 18.67 20.39 12.55 12.02 25.15 41.28 13.87 36.56III 8.43 15.76 16.00 8.60 17.38 33.65 37.75 32.19

671.4 685.8 505.1 456.5 529.2 605.4 672.9 940.71598 1633 1203 1087 1260 1442 1602 2240

Mar

Apr

May

Runoff Depth (mm)

PERIOD

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Annual (MCM)

Jan

Feb



161133-40ER-0007-00 5-18

Table 5-6 (Contd..): Flow Series at Par Project Site

1986-87 1987-88 1988-89 1989-90 1990-91 1991-92 1992-93 1993-94

I 27.33 56.79 73.03 30.06 45.94 38.84 16.61 48.64II 40.48 48.37 72.40 63.94 26.26 45.26 17.09 53.73III 67.95 59.03 78.46 22.41 60.60 50.02 50.19 70.64I 19.45 86.08 100.48 28.25 35.54 52.57 30.12 46.42II 35.61 63.38 85.99 47.47 45.27 45.31 54.91 31.70III 46.86 83.12 114.67 67.30 45.64 31.78 57.00 28.75I 61.70 63.16 18.22 28.47 29.17 39.85 44.50 30.13II 37.72 86.12 23.02 30.01 28.92 43.39 30.70 35.88III 54.22 96.12 60.22 46.59 35.95 37.83 38.18 33.98I 36.75 85.35 29.14 27.26 26.73 43.08 21.28 37.93II 69.00 77.90 23.41 47.84 38.22 35.49 22.42 32.13III 41.58 112.71 25.74 39.52 53.75 34.74 21.73 35.78I 38.71 80.14 23.35 34.84 50.01 23.43 16.81 33.45II 37.70 41.14 15.15 37.37 40.15 32.68 30.54 28.98III 42.87 18.33 28.17 25.36 24.96 20.59 17.15 29.77I 27.14 13.96 12.19 23.75 18.00 15.93 11.70 16.41II 22.47 11.96 10.79 21.23 15.30 13.59 10.88 13.10III 19.03 11.07 11.37 15.06 12.76 11.88 9.92 12.66I 17.89 10.14 10.30 10.96 9.46 10.93 10.16 12.52II 17.76 10.29 9.67 9.56 10.27 9.77 7.97 12.78III 18.30 10.45 10.31 12.44 10.56 11.93 7.88 12.60I 15.90 9.28 8.94 9.50 9.46 8.84 10.17 12.00II 15.35 9.21 9.27 9.30 8.23 8.72 10.97 12.38III 16.03 9.94 10.02 11.90 8.33 8.85 8.95 11.84I 18.91 9.33 8.97 13.98 7.42 8.61 7.64 11.73II 18.74 9.39 10.95 13.22 10.49 9.33 18.34 11.81III 18.11 9.05 9.26 14.60 7.88 8.10 7.38 11.84I 21.69 10.77 10.23 15.20 8.11 35.34 7.52 13.70II 32.84 15.39 12.36 15.31 10.49 14.24 11.64 15.79III 32.96 12.62 14.62 19.76 9.59 21.66 12.29 24.96I 44.90 12.63 17.70 17.58 23.37 13.93 8.34 25.86II 35.97 16.92 11.64 26.58 10.29 23.94 15.67 12.34III 48.03 14.67 10.63 35.54 11.07 13.98 11.15 23.82I 40.48 19.74 13.64 21.95 44.96 17.24 34.96 14.27II 38.26 56.61 8.33 26.66 32.19 26.88 24.40 15.03III 44.97 110.40 15.42 22.72 22.36 19.23 16.98 17.64

1076.2 1282.0 891.3 830.5 779.2 778.8 646.7 783.32562 3052 2122 1977 1855 1854 1540 1865

Mar

Apr

May

Runoff Depth (mm)

PERIOD

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Annual (MCM)

Jan

Feb



161133-40ER-0007-00 5-19


1994-95 1995-96 1996-97 1997-98 1998-99 1999-00 2000-01

I 80.19 24.58 33.68 45.85 36.24 31.63 32.62II 32.53 42.69 22.39 55.32 53.66 25.94 50.22III 40.81 50.78 53.89 45.75 55.53 21.81 55.39I 55.74 94.09 53.67 40.74 51.39 44.00 39.75II 27.51 81.63 58.85 45.97 52.32 45.30 45.12III 28.21 43.85 37.90 37.55 48.04 41.80 30.05I 28.97 35.32 33.10 38.45 46.40 30.76 51.44II 37.45 55.96 52.16 43.69 54.72 41.81 40.41III 35.62 36.08 37.64 34.29 46.47 47.67 33.04I 26.93 44.00 36.72 33.93 45.53 49.01 38.49II 32.54 31.07 30.70 41.86 36.41 37.85 42.45III 29.21 48.10 44.38 41.55 37.63 28.71 37.17I 23.04 32.52 40.29 32.08 33.62 41.94 24.29II 32.43 28.89 28.18 24.14 31.18 43.35 14.58III 17.97 26.47 32.76 21.87 36.31 49.40 12.19I 22.12 24.11 29.03 20.56 29.69 33.29 10.79II 17.03 26.43 25.14 19.85 26.79 31.35 11.73III 15.76 16.12 25.16 19.15 25.44 25.50 10.88I 16.90 14.97 20.04 18.17 22.83 22.27 5.72II 15.15 15.53 18.45 14.58 20.15 17.79 5.60III 13.68 14.43 16.54 16.31 18.03 13.64 6.14I 13.75 12.15 15.94 15.62 16.11 12.28 5.72II 13.64 12.61 13.97 16.15 14.61 11.91 5.60III 13.76 12.40 13.18 15.98 13.02 12.15 6.14I 13.02 11.43 13.95 15.68 12.00 12.56 5.37II 17.16 11.38 14.80 15.79 10.90 12.41 5.12III 14.29 11.95 13.62 17.78 10.44 13.05 6.50I 15.03 11.60 12.51 17.19 10.14 16.03 5.98II 12.96 22.76 29.44 16.52 8.80 15.65 5.64III 12.80 13.74 21.53 25.78 8.40 14.06 11.77I 13.93 12.19 27.09 26.18 9.52 18.63 11.81II 16.82 16.10 21.01 32.92 8.23 16.65 7.22III 15.38 17.74 16.11 21.03 25.12 29.34 25.96I 21.97 43.10 22.20 19.88 30.34 32.14 18.41II 22.27 47.00 23.77 18.35 24.52 12.14 15.09III 39.08 32.27 37.24 27.42 35.75 40.14 28.62

776.6 943.1 902.0 871.2 920.0 875.5 669.21849 2246 2148 2074 2190 2084 1593

Mar

Apr

May

Runoff Depth (mm)

PERIOD

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Annual (MCM)

Jan

Feb



161133-40ER-0007-00 5-20


2001-02 2002-03 2003-04 2004-05 2005-06 2006-07 2007-08

I 38.07 48.51 48.51 23.30 17.12 30.47 54.12II 33.34 62.68 62.68 27.17 11.29 71.74 64.63III 36.83 40.23 32.29 88.48 16.99 37.20 51.17I 20.95 75.50 43.89 60.15 13.37 27.37 28.27II 33.24 60.02 32.16 65.00 54.56 30.62 36.90III 42.28 123.81 36.50 43.61 19.24 32.87 87.66I 38.34 58.42 35.40 35.56 133.23 16.03 35.10II 29.86 54.85 34.40 23.69 23.10 12.04 32.63III 56.39 42.47 30.37 22.38 84.31 17.41 37.08I 47.64 29.80 39.78 35.75 22.90 11.14 32.27II 44.97 27.21 27.60 23.16 18.85 22.90 36.56III 37.32 34.93 24.90 20.45 78.67 12.07 33.90I 48.81 31.84 24.58 53.72 25.22 9.03 22.83II 36.33 23.85 26.23 28.09 18.87 7.54 30.46III 26.00 21.86 17.52 16.90 18.43 6.54 14.28I 23.81 18.02 13.72 11.77 14.32 5.92 11.63II 20.55 19.17 9.98 10.60 12.56 6.88 10.83III 18.45 13.93 8.97 8.21 11.62 10.62 9.48I 18.23 11.37 8.25 6.61 8.75 7.09 8.84II 18.07 9.88 5.92 5.78 7.97 6.99 7.10III 12.25 10.38 4.39 5.56 6.81 6.70 6.36I 10.87 9.59 3.96 6.25 6.23 6.43 6.43II 10.21 7.72 4.42 5.04 6.01 6.10 8.05III 11.32 7.24 5.90 4.92 5.91 6.20 7.15I 7.99 8.64 4.61 5.47 5.42 8.09 7.60II 7.68 7.62 4.74 9.15 5.45 9.40 7.86III 7.57 8.21 6.35 9.32 10.69 7.93 7.82I 8.20 7.70 8.02 11.23 5.88 7.78 11.21II 14.79 16.00 5.36 12.79 5.50 10.03 12.77III 17.98 11.80 18.66 13.88 5.33 7.96 13.73I 60.32 21.02 11.01 9.03 5.88 15.56 10.15II 58.37 27.09 27.03 7.54 8.07 9.88 10.14III 42.02 21.90 15.87 9.88 7.09 9.46 10.75I 23.75 14.25 11.38 10.12 10.62 7.76 22.17II 26.05 10.74 39.01 14.90 14.48 11.30 23.80III 29.96 25.42 33.92 13.62 17.16 44.16 30.27

895.9 904.0 675.4 664.7 649.3 490.6 743.12133 2152 1608 1583 1546 1168 1769

Mar

Apr

May

Runoff Depth (mm)

PERIOD

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Annual (MCM)

Jan

Feb

5.3.6 Flow Duration Curves and Annual Dependabilities

Having prepared the long term 10-daily flow series for the project, dependabilities of the

annual inflows has been derived using the Weibull plotting position formula, where the

probability of an event equaled to or exceeded is given by,



161133-40ER-0007-00 5-21

1

N

mP

where:

m = Annual Runoff order in Descending Order

N = Total no of years of Record

The computation has been tabulated in Table 5-7.

Table 5-7: Computation of Dependabilities of Annual Inflow

(Right Side Period is rearranged in Descending Order of Annual Runoff)

S.No. Period Runoff (MCM)

Period Runoff (MCM) in

descending orderm/(n+1)

1 1978-79 671 1987-88 1282 0.03

2 1979-80 686 1986-87 1076 0.06

3 1980-81 505 1995-96 943 0.10

4 1981-82 456 1985-86 941 0.13

5 1982-83 529 1998-99 920 0.16

6 1983-84 605 2002-03 904 0.19

7 1984-85 673 1996-97 902 0.23

8 1985-86 941 2001-02 896 0.26

9 1986-87 1076 1988-89 891 0.29

10 1987-88 1282 1999-00 875 0.32

11 1988-89 891 1997-98 871 0.35

12 1989-90 830 1989-90 830 0.39

13 1990-91 779 1993-94 783 0.42

14 1991-92 779 1990-91 779 0.45

15 1992-93 647 1991-92 779 0.48

16 1993-94 783 1994-95 777 0.52 50% dependable

17 1994-95 777 2007-08 743 0.55

18 1995-96 943 1979-80 686 0.58

19 1996-97 902 2003-04 675 0.61

20 1997-98 871 1984-85 673 0.65

21 1998-99 920 1978-79 671 0.68

22 1999-00 875 2000-01 669 0.71

23 2000-01 669 2004-05 665 0.74

24 2001-02 896 2005-06 649 0.77 75% dependable

25 2002-03 904 1992-93 647 0.81

26 2003-04 675 1983-84 605 0.84

27 2004-05 665 1982-83 529 0.87

28 2005-06 649 1980-81 505 0.90 90% dependable

29 2006-07 491 2006-07 491 0.94

30 2007-08 743 1981-82 456 0.97



161133-40ER-0007-00 5-22

The flow duration curves for all available years, 90%, 75%, 50% dependable years and also

the flow duration curve of the available observed data at Par project site has been given in

the Figure 5-13 to Figure 5-17 respectively.

Flow Duration Curve-All Year

0

50

100

150

0 10 20 30 40 50 60 70 80 90 100

Percentage of Exceedence

Dis

char

ge

(cu

mec

)

Figure 5-13: Flow Duration Curve at Par Diversion Site for All 30 years series

Flow Duration Curve-90% Dependable Year

0

10

20

30

40

50

0 10 20 30 40 50 60 70 80 90 100


Dis

char

ge

(cu

mec

)

Figure 5-14: Flow Duration Curve of 90% Dependable Year



161133-40ER-0007-00 5-23

Flow Duration Curve of 75% Dependable Year

0

50

100

150

0 10 20 30 40 50 60 70 80 90 100


Dis

char

ge

(cu

mec

)


Flow Duration Curve of 50% Dependable Year

0

10

20

30

40

50

60

70

80

90

0 10 20 30 40 50 60 70 80 90 100


Dis

char

ge

(cu

mec

)




161133-40ER-0007-00 5-24

Flow Duration Curve of Observed Data at Par Project Site

0

50

100

150

200

0 10 20 30 40 50 60 70 80 90 100


Dis

char

ge

(cu

mec

)

Figure 5-17: Flow Duration Curve of Observed Data at Par G & D Site

5.4 Design Flood and Rating Curves

5.4.1 General

Estimation of design flood is a significant component of hydrological studies. Proper

selection of design flood value is important as an over-estimated value results in increase in

the cost of hydraulic structures, while an under-estimated value will place the structure and

population at risk.

5.4.2 Approaches for Estimation of Design Flood

The following two approaches are commonly used for estimation of design flood:

a. Probabilistic Approach (Flood frequency analysis)

The Probabilistic approach is a common procedure for analysis of flood data at a gauged

location. This approach can also be applied to any type of hydro-meteorological data, but it

is widely used with flood data. Therefore, it is sometimes designated as flood frequency

analysis.



161133-40ER-0007-00 5-25

b. Hydro-meteorological Approach.

The concepts of the Standard Project Flood as also the Probable Maximum Flood are based

on estimating the Standard Project Storm or the Probable Maximum Precipitation, as the

case may be, and then estimating the resulting flood under the assumption that the

catchment conditions are favorable to large runoff.

The Hydro-meteorological approach requires short term rainfall-runoff records along with

physiographic characteristics at the project site and in the upper catchment. This approach is

considered the most rational method for flood estimation. This method, preferably based on

site specific information, is recommended for estimating design flood for intermediate and

large dams, especially when storage has a significant effect on modifying the design flood

hydrograph as it flows through the reservoir. The main advantage of this approach as

compared to the Probabilistic approach is that it gives a complete flood hydrograph and thus

allows making a realistic determination of its moderating effect while passing through a

reservoir or a river reach.

5.4.3 Flood Estimation by Probabilistic Approach

Data Available

Annual Instantaneous flood peaks at the project site is required for determination of different

return period/frequency of floods at the project site. At present there is only one complete

water year (2012-13) data at the Par project site is available. However, long-term annual

flood peaks are available at Hoz G&D site (CA=803.35km2) which is downstream of the

proposed site of Par. Hence, it has been proposed to transpose the flood peaks of Hoz G&D

site to the proposed project site by Dicken’s formula and enhanced it by enhanced by 15%

for instantaneous peak factor. The peaks thus obtained has been subjected to frequency

analysis to derive the different return period floods at the Project site. The formula thus used

for deriving the final flood peaks at Par project site is as follows:

QPar = 1.15* (APar / AHoz G&D) 0.75 * Q Hoz G&D

where,

QPar = Final peak flow at Par

Q Hoz G&D = Observed flood peak at Hoz G&D

APar = Catchment area of Par (=420km2)

A Hoz G&D = Catchment area at Hoz G&D Site



161133-40ER-0007-00 5-26

The details of annual peak flows thus arrived at project site have been given in Table 5-8

below:

Table 5-8: Details of Annual Peak flow at Par

Year Peak Flood at Hoz G&D Site

(cumec)

Peak Flood at Par Site (cumec)

Hoz G&D Site peak transposed to Par (cumec)

Final Inst. Peak at diversion site

(cumec)

1986-87 340.00 - 209.04 240.40

1987-88 341.00 - 209.66 241.11

1988-89 340.00 - 209.04 240.40

1989-90 308.00 - 189.37 217.77

1990-91 555.00 - 341.23 392.42

1991-92 425.00 - 261.30 300.50

1992-93 485.00 - 298.19 342.92

1993-94 761.00 - 467.89 538.07

1994-95 500.00 - 307.42 353.53

1995-96 312.00 - 191.83 220.60

1996-97 592.00 - 363.98 418.58

2005-06 620.76 - 381.66 438.91

2006-07 286.38 - 176.07 202.49

2007-08 226.75 - 139.41 160.32

2012-13 - 269.15 - 309.52

Statistical Parameters

The detail of important statistical parameters for the annual instantaneous flood peaks at the

project site is given in Table 5-9 below.



161133-40ER-0007-00 5-27

Table 5-9: Detailed Statistics for Instantaneous Peak Flow Data

S.No. Parameter Value Log Transformed

Value

1 Mean 307.84 5.68

2 Variance 11079.4 0.114

3 Standard Deviation 105.259 0.337

4 Skewness 0.69779 0.10378

5 Kurtosis -0.10409 -0.72789

Outlier and Randomness Check

A. Outlier Check

Outliers are data points which depart significantly from the trend of the remaining data of the

sample. The high outlier and low outlier tests for the data series has been carried out as

follows:

High outlier threshold: Qh = exp (Xh)

Low outlier threshold: QL = exp (XL)

Where,

X h= High outlier threshold in log units

X L= Low outlier threshold in log units

X m= Mean of the log transformed series

Sx = Standard deviation of the log transformed series

Kn = Outliers test K values for 10 % significance level for a Normal distribution.

The data series will have no outlier if,

Qh > Maximum of Observed Series

Ql < Minimum of Observed Series

Using the above equations, the high outlier and low outlier tests have been carried out, the

details of which are given in the following Table 5-10.

xnmh SKXX

xnmL SKXX



161133-40ER-0007-00 5-28

Table 5-10: Outlier Test for Annual Peak Flow

Parameters Value

Mean(Xm) 5.68

SD (Sx) 0.337

Variance 0.114

Skewness 0.10378

Kurtosis -0.72789

No. of Data 15

Kn 2.247

High outlier threshold Xh 622.96

Low outlier threshold Xl 136.75

Maximum Value 538.07

Minimum Value 160.32

Check on High Outlier OK

Check on Low Outlier OK

From the above table it is seen that there is no outlier in the flood peak values.

B. Randomness Check

The sequence and chance of a variable occurring in a probabilistic process is assumed to

follow a definite probability distribution in which the variables are considered to be purely

random. In a random process, the value of the variate does not depend on the previous or

the next value i.e., all the values occur purely by chance.

For the present project, the randomness has been checked based on the number of peaks

and troughs in the data series.

The randomness check has been performed as follows:

þ =

If, þ < 1.96, the series is random at 5% significance level.

where,

P = number of turning points i.e., total number of peaks and troughs in the series = 9

)var(

)(

p

pEP



161133-40ER-0007-00 5-29

E (p) = 2/3(N-2) =8.67

Var(p) = (16N-29)/90 = 2.34

N= no. of data points = 15

Hence, þ = 0.22

The þ value is less than 1.96 and hence it can be inferred that the data series are

independent of one another and the variables does not depend on previous or next value.

Flood Frequency Analysis

The flood frequency analysis has been carried out in order to estimate the flood of the

different return periods by method of moments (MOM) adopting following distributions:

(i) Gumbel Distribution

(ii) Log Normal Distribution

(iii) Log Pearson Type III Distribution

The flood peak values for different return periods as arrived by using the above distribution is

given in Table 5-11 below:

Table 5-11: Return Period Flood

S.No. Return Period

(Years)

Flood Peak (cumec)

Log-Normal Log-Pearson III Gumbel

1 25 527 533 585

2 50 584 595 657

3 100 640 656 729

4 500 771 804 896

The result of the flood frequency analysis has been shown graphically in Figure 5-18 below:



161133-40ER-0007-00 5-30

0

200

400

600

800

1000

1200

0.0010.0100.1001.000

Probability

Flo

w (

m3 /s

)

1 10 100 1000

Return Period

Observed Data Points

Log Normal

Log Pearson Type-III

Gumbel Prob. Distribution

Lower Confidence Limit

Upper Confidence Limit

Figure 5-18: Plot of Flood Frequency Analysis

5.4.4 Flood Estimation by Hydro-meteorological Approach

The hydro-meteorological approach has been found to be a useful tool in the design flood

studies. This method is based on site specific information. The concepts of the design flood

are based on estimating the design storm, and then estimating the resulting flood under the

assumption that the catchment conditions are favorable to large runoff.

In the absence of site specific short interval rainfall-runoff records, the procedure for

estimation of unit hydrograph given in “Flood Estimation Report for North Brahmaputra,

subzone 2(a), Central Water Commission, 1991” is adopted.

Physiographic Parameters of the Catchment

A. Catchment Area (A)

The project catchment area is 420km2, derived by delineating the relevant toposheets.

B. Parameters of the Main Stream (L & Lc)

River length (L) implies the longest length of the main river from the farthest watershed

boundary of rain-fed catchment to the downstream boundary point, whereas Lc is defined as

the length of the longest main stream from a point opposite to centroid of the catchment area



161133-40ER-0007-00 5-31

to the gauging site (i.e., the outlet point) along the main stream. The stream may or may not

pass through the centre of gravity but the point of the river nearest to the centre of gravity is

considered to find the length of the main river from the centre of gravity to the point of study

(Lc). In the present case, “L” and “Lc” has been estimated to 45.98km and 19.097km

respectively.

C. Equivalent Stream Slope (S)

This is one of the physiographic parameters used in the derivation of Synthetic Unit

Hydrograph. The L-section of the river is derived from relevant toposheets. It is broadly

divided into segments representing broad ranges of slopes. The following formula is used to

compute equivalent slope (S).

2

)1( )(

L

DDLS iii

Elevations of riverbed at intersection points of contours reckoned from the bed elevation at

the diversion site are considered as datum. D(i-1) and Di are the heights of successive bed

locations at contour intersections. Details of catchment elevations are graphically shown

below in Figure 5-19.

Longitudinal Section of Par

11001200

13001400

15001600

17001800

19002000

21002200

23002400

1000

800900

0

500

1000

1500

2000

2500

0 5 10 15 20 25 30 35 40 45 50

Distance, km

Ele

vati

on

, m

Figure 5-19: L-Section of Par Catchment



161133-40ER-0007-00 5-32

The computation of equivalent slope is given in Table 5-12. The equivalent slope as

computed for the catchment is 27.09m/km.

Table 5-12: Computation of Equivalent Slope

Distance from Outlet(km)

Elevation (m)

Distance between twoconsequtive points (L), km

Elevation from site (Di), m

Di+Di-1 L*( Di+Di-1)

0.00 800 0.00 200 200 0.003.92 900.00 3.92 300 500 1960.50

20.49 1000.00 16.57 400 700 11599.0026.01 1100.00 5.52 500 900 4968.0027.84 1200.00 1.83 600 1100 2013.0032.88 1300.00 5.04 700 1300 6546.8033.89 1400.00 1.01 800 1500 1521.0035.88 1500.00 1.99 900 1700 3379.6038.20 1600.00 2.32 1000 1900 4413.7039.72 1700.00 1.52 1100 2100 3185.7040.62 1800.00 0.91 1200 2300 2081.5042.13 1900.00 1.51 1300 2500 3770.0042.87 2000.00 0.74 1400 2700 1987.2043.73 2100.00 0.87 1500 2900 2508.5044.53 2200.00 0.79 1600 3100 2458.3045.53 2300.00 1.00 1700 3300 3300.0045.98 2400.00 0.45 1800 3500 1585.50

57278.30Equivalent slope = 27.09m/km

Derivation of Unit Hydrograph

The Central Water Commission (CWC) in association with India Meteorological Department

(IMD), Ministry of Railway and Ministry of Surface Transport has prepared flood estimation

reports for small & medium rainfed catchments for efficient hydro-meteorological

homogenous sub-zones. These reports illustrate the procedure for derivation of synthetic

unit hydrograph based on physiographic parameters. The unit hydrograph for the rainfed

catchment area of the project have been derived as per procedure and guidelines given in

the regional flood report of sub zone 2a.

The detail parameters of a synthetic unit hydrograph (SUH) are described in Figure 5-20

below for understanding the important inputs of design flood computations.



161133-40ER-0007-00 5-33

Figure 5-20: Parameters of SUH

Where;

A [km2] = Total rainfed Catchment area up to diversion site

L [km] = Length of longest main stream along the river course

LC [km] = Length of longest main stream from a point opposite to

centroid of the Catchment area to point of study

Seq [m/km] = Equivalent stream slope

tr [hr] = Unit duration

tp [hr] = Time from the centre of effective rain fall duration to the Unit

Hydrograph (U.G) Peak

tm [hr] = Time from start of rise to the peak of U.G.

TB [hr] = Base width of U.G.

qp [m3/s/km2] = Peak Discharge

Qp [m3/s] = Peak Discharge of unit hydrograph

W50 [hr] = Width of U.G. measured at 50% of Peak Discharge Ordinate

W75 [hr] = Width of U.G. measured at 75% of peak discharge ordinate

WR50 [hr] = Width of the rising limb of U.G. measured at 50% of Peak

Discharge Ordinate

WR75 [hr] = Width of the rising limb of U.G. measured at 75% of Peak Discharge

Ordinate



161133-40ER-0007-00 5-34

The value of the above stated parameters for deriving unit hydrograph has been given in

Table 5-13 below:

Table 5-13: Unit Hydrograph Parameters

Parameters Formula Values

qp 409.0

*272.2

S

LL c 0.55m³/s/km²

tp 940.0*164.2 Pq 3.81 hr

tm tp + 0.5 4.31 hr (say, 4 hr)

W50 065.1*084.2 Pq 3.96 hr

W75 071.1*028.1 Pq 1.96 hr

WR50 865.0*856.0 Pq 1.44 hr

WR75 918.0*44.0 Pq 0.76 hr

TB 852.0*428.5 Pt 16.97 hr

Qp rP xAq 230 cumec

The 1-hour Synthetic Unit Hydrograph (SUH) representing effective rainfall depth of 1 cm

has been obtained for the catchments using the above parameters. The SUH for the

catchment is shown in Figure 5-21 below:

0

50

100

150

200

250

0 2 4 6 8 10 12 14 16 18 20 22 24Time (hr)

Flo

w (

m³/

s)

Figure 5-21: SUH of Par Catchment



161133-40ER-0007-00 5-35

The important parameters for deciding critical storm duration are size and shape of the

catchment, travel time/base period of unit hydrograph and the direction of the storm

movement with reference to the direction of river flow. For all practical purposes, the UG

base governs the duration of the storm. As can be seen from the above figures, the base

period of unit hydrograph is 16.97 hours. Therefore, design storm of 1 day has been

proposed to be used for the flood estimation.

Design Storm

Design storm studies for the project have been carried out by the India Meteorological

Department (IMD), New Delhi on the basis of the available rainfall data in the area.

The 1-day Standard Project Storm (SPS) and Probable Maximum Precipitation (PMP) values

of the project as provided by IMD are 26.5 cm and 33.1 cm respectively. The 1-day design

storm values are enhanced by 15% (as recommended by IMD) to convert them into any

24-hour value. The 24-hour SPS and PMP values for the project have been estimated to

30.475cm and 38.065 cm respectively. The temporal distribution of the design storm as

provided by IMD is given Table 5-14. A copy of the values supplied by IMD along with its

temporal distribution in graphical form has also been enclosed as Annexure 5-3.

The design storm values for the 50-year and 100-year return period has been adopted from

the “Atlas of Generalised Isopluvial Maps of Eastern India (Part-II)”, Published by IMD, New

Delhi. Accordingly, the 24-hour 50-year and 100-year return period design storm values has

been taken as 280mm and 320mm respectively. These point storm values has been

converted to areal by applying a correction factor of 0.866 for 420km2 as per report of

subzone-2a. Accordingly, 24-hour 50 and 100-year areal design storm value for the project

has been computed to 24.25 cm and 27.72 cm respectively.

Table 5-14: Temporal Distribution of 24-hour Design Storm

Duration (hrs) 24-hour (%)

0 0

3 41

6 57

9 68

12 78

15 85

18 91

21 96

24 100



161133-40ER-0007-00 5-36

Distribution of Design Storm

The 24-hr design storm is distributed into 2-bells of 12 hour each in ratio of 0.78 and

0.22 respectively according to the hourly percentages of 24-hour rainfall as given below in

Table 5-15.

Table 5-15: Distribution of 24-hour Design Storm

Design Storm, cm Ratio of 12/24 hr rainfall

Storm Distribution (cm)

I-Bell II-Bell I-Bell II-Bell

SPS 30.475 0.78 0.22 23.77 6.70

100-Year 27.72 0.78 0.22 21.62 6.10

50-Year 24.24 0.78 0.22 18.91 5.33

Design Loss Rate

Direct surface runoff is the end product of the storm rainfall after deduction of infiltration in to

the sub surface soils, initial ground losses and evaporation etc. The design loss rate for the

project has been assumed to be 0.24 cm/hr as per report of Subzone-2a.

Critical Sequence of Rainfall Excess

The critical sequencing of the rainfall excess is done as per the prevailing practice.

The highest rainfall ordinate is placed against the maximum UG ordinate and next ranking

rainfall against the next ranking UG ordinate. This critical sequence is reversed to obtain the

maximum peak.

The rainfall excess for the catchment for 50-year return period, 100-year return period and

SPF has been given in Table 5-16 to Table 5-18 respectively whereas the critical

sequencing of the rainfall excesses are given in Table 5-19.



161133-40ER-0007-00 5-37

Table 5-16: Rainfall Excesses for 50-Year Return Period

Distribution coefficient

Cumulative Rainfall

Rainfall increment

Rainfall excess incremental

Cumulative Rainfall

Rainfall increment


(cm) (cm) (cm) (cm) (cm) (cm)1 0.231 4.36 4.36 4.125 1.23 1.23 0.9912 0.397 7.52 3.15 2.912 2.12 0.89 0.6493 0.526 9.94 2.42 2.185 2.80 0.68 0.4444 0.603 11.40 1.45 1.215 3.21 0.41 0.1705 0.667 12.61 1.21 0.972 3.56 0.34 0.1026 0.731 13.82 1.21 0.972 3.90 0.34 0.1027 0.778 14.71 0.89 0.649 4.15 0.25 0.0118 0.825 15.60 0.89 0.649 4.40 0.25 0.0119 0.872 16.49 0.89 0.649 4.65 0.25 0.011

10 0.915 17.30 0.81 0.568 4.88 0.23 0.00011 0.957 18.11 0.81 0.568 5.11 0.23 0.00012 1.000 18.91 0.81 0.568 5.33 0.23 0.000

Time

I-Bell II-Bell

Table 5-17: Rainfall Excesses for 100-Year Return Period


Cumulative Rainfall

Rainfall increment


Cumulative Rainfall

Rainfall increment


(cm) (cm) (cm) (cm) (cm) (cm)1 0.231 4.99 4.99 4.748 1.407 1.407 1.1672 0.397 8.59 3.60 3.363 2.423 1.016 0.7763 0.526 11.36 2.77 2.531 3.205 0.782 0.5424 0.603 13.02 1.66 1.423 3.674 0.469 0.2295 0.667 14.41 1.39 1.146 4.064 0.391 0.1516 0.731 15.80 1.39 1.146 4.455 0.391 0.1517 0.778 16.81 1.02 0.776 4.742 0.287 0.0478 0.825 17.83 1.02 0.776 5.028 0.287 0.0479 0.872 18.84 1.02 0.776 5.315 0.287 0.047

10 0.915 19.77 0.92 0.684 5.576 0.261 0.02111 0.957 20.69 0.92 0.684 5.836 0.261 0.02112 1.000 21.62 0.92 0.684 6.097 0.261 0.021

Time

I-Bell II-Bell



161133-40ER-0007-00 5-38

Table 5-18: Rainfall Excesses for SPF


Cumulative Rainfall

Rainfall increment


Cumulative Rainfall

Rainfall increment


(cm) (cm) (cm) (cm) (cm) (cm)1 0.231 5.49 5.49 5.246 1.55 1.55 1.3072 0.397 9.45 3.96 3.722 2.66 1.12 0.8773 0.526 12.49 3.05 2.808 3.52 0.86 0.6204 0.603 14.32 1.83 1.589 4.04 0.52 0.2765 0.667 15.85 1.52 1.284 4.47 0.43 0.1906 0.731 17.37 1.52 1.284 4.90 0.43 0.1907 0.778 18.49 1.12 0.877 5.21 0.32 0.0758 0.825 19.61 1.12 0.877 5.53 0.32 0.0759 0.872 20.72 1.12 0.877 5.84 0.32 0.075

10 0.915 21.74 1.02 0.776 6.13 0.29 0.04711 0.957 22.75 1.02 0.776 6.42 0.29 0.04712 1.000 23.77 1.02 0.776 6.70 0.29 0.047

Time

I-Bell II-Bell

Table 5-19: Critical Sequencing of Rainfall Excess

Time (hr)

UG-ordinates

(m3/s)

For 50-Year Return Period

For 100-Year Return Period

For SPF

I-bell II-bell I-bell II-bell I-bell II-bell

0 0

1 32 0.568 0.000 0.684 0.021 0.776 0.047

2 65 0.649 0.011 0.776 0.047 0.877 0.075

3 118 1.215 0.170 1.423 0.229 1.589 0.276

4 230 4.125 0.991 4.748 1.167 5.246 1.307

5 202 2.912 0.649 3.363 0.776 3.722 0.877

6 152 2.185 0.444 2.531 0.542 2.808 0.620

7 115 0.972 0.102 1.146 0.151 1.284 0.190

8 84 0.972 0.102 1.146 0.151 1.284 0.190

9 59 0.649 0.011 0.776 0.047 0.877 0.075

10 42 0.649 0.011 0.776 0.047 0.877 0.075

11 29 0.568 0.000 0.684 0.021 0.776 0.047

12 17 0.568 0.000 0.684 0.021 0.776 0.047

13 10

14 6

15 4

16 2

17 0



161133-40ER-0007-00 5-39

Base flow

The base flow value chosen should be characteristics of the storm season and should

preferably be based on observed flood hydrograph. The base flow for the study has been

assumed @ 0.05 cumec/km2 as specified in the report of subzone-2a. The base flow for the

catchment has been estimated to 21 cumec.

Surface Flow Hydrograph

The Surface Flow Hydrograph has been computed by convoluting 1-hour rainfall excess

increments with the ordinates of the 1-hr Unit Hydrograph. For this purpose, the rainfall

excess increments have been arranged in a critical sequence. Each of the individual

incremental hydrographs has been lagged 1-hour from the previous one in the assumed

critical sequence and added to obtain the surface flow hydrograph.

Flood Hydrograph

The Flood Hydrograph has been obtained by adding a uniform base flow, including

snowmelt, to the ordinates of the surface flow hydrograph. The flood hydrograph for 50-year

return period, 100-year return period and SPF thus obtained has been given in Figure 5-22

to Figure 5-24 respectively. The 50-year return period, 100-year return period flood and

Standard Project flood at the project site has been estimated to be 2382m3/s, 2759m3/s and

3060m3/s respectively.

50 Year Return Period Hydrograph

0

500

1000

1500

2000

2500

0 5 10 15 20 25 30 35 40 45 50

Time (hr)

Dis

char

ge (

cum

ec)

Figure 5-22: 50-Year Return Period Flood Hydrograph



161133-40ER-0007-00 5-40

100 Year Return Period Hydrograph

0

500

1000

1500

2000

2500

3000

0 5 10 15 20 25 30 35 40 45 50

Time (hr)

Dis

char

ge (

cum

ec)

Figure 5-23: 100-Year Return Period Flood Hydrograph

SPF Hydrograph

0

500

1000

1500

2000

2500

3000

3500

0 5 10 15 20 25 30 35 40 45 50

Time (hr)

Dis

char

ge (

cum

ec)

Figure 5-24: Standard Project Flood Hydrograph

The tabulation of 50-year return period, 100-year return period and Standard Project Flood

hydrograph has been given in Table 5-20 below:



161133-40ER-0007-00 5-41

Table 5-20: 50 and 100-Year Return Period flood and SPF Hydrograph Values

Hours

50-Year RP Flood Values (m3/s)

100-Year RP Flood

Values (m3/s)

SP Flood Values (m3/s)

Hours

50-Year RP Flood

Values (m3/s)

100-Year RP Flood

Values (m3/s)

SP Flood Values (m3/s)

0 21 21 21 26 1765 2051 2279

1 21 22 22 27 1408 1638 1822

2 21 23 26 28 1043 1213 1350

3 21 26 32 29 747 869 965

4 22 33 44 30 527 612 679

5 26 43 61 31 360 417 463

6 35 59 82 32 235 272 301

7 59 92 120 33 154 176 195

8 110 154 191 34 101 115 126

9 194 253 302 35 67 75 81

10 308 385 448 36 44 48 51

11 417 511 587 37 29 31 32

12 490 595 679 38 25 25 26

13 445 544 624 39 22 22 23

14 386 477 550 40 21 21 21

15 376 463 535 41 21 21 21

16 448 546 626

17 533 645 735

18 623 747 848

19 754 898 1013

20 969 1144 1284

21 1294 1515 1692

22 1716 1998 2223

23 2118 2457 2728

24 2382 2759 3060

25 2142 2484 2756

The convolution of unit hydrograph with rainfall excesses has been given in Annexure 5-4.



161133-40ER-0007-00 5-42

Summary of Project Flood Values

The summary of design flood values as obtained by both hydro-meteorological approach

and Probabilistic approach (adopting Gumbel’s frequency analysis) is shown in Table 5-21

below:

Table 5-21: Summary of Project Design Flood

S.No. Flood Type Flood Value (cumec) Computation Approach

1 25-Year Return Period 585 Probabilistic

2 50-Year Return Period 2382 Hydro-meteorological

657 Probabilistic

3 100-Year Return Period 2759 Hydro-meteorological

729 Probabilistic

4 500-Year Return Period 896 Probabilistic

5 Standard Project Flood 3060 Hydro-meteorological

From the above table it can be seen that there are differences in the flood magnitudes

derived by both approaches. Generally, flood value worked out by hydro-meteorological

approach is preferred over the flood values obtained by frequency approach. Hence, based

on the type and height of the hydraulic structure along with the gross capacity of the

reservoir and the criteria provided in the related IS Code for selecting design flood, the

respective flood value obtained by hydro-meteorological approach may be used for the

design of hydraulic structure.

5.4.5 Design Flood for River Diversion Works

As per IS 14815:2000, the diversion capacity for concrete dam and barrage must be the

higher of the following criteria:

Maximum non-monsoon flow observed at the dam site;

25 years non-monsoon flow, calculated on the basis of non-monsoon yearly peaks.

The non monsoon season for this project has been taken as October to May which can be

used for construction activities at project site. At present there is only one complete water

year (2012-13) data at the Par project site is available. However, non-monsoon flood peaks

are available at Hoz-Dam site (CA = 803.35km2) which is downstream of the proposed site at

Par. Hence, it has been proposed to transpose the flood peaks of Hoz G&D site to the



161133-40ER-0007-00 5-43

proposed project site by Dicken’s formula and enhanced it by enhanced by 15% for

instantaneous peak factor. The peaks thus obtained have been subjected to frequency

analysis to derive the different return period floods at the Project site. The formula thus used

for deriving the final flood peaks at Par project site is as follows:

QPar = 1.15* (APar / AHoz G&D) 0.75 * Q Hoz G&D

where,

QPar = Final peak flow at Par

Q Hoz G&D = Observed flood peak at Hoz G&D

APar = Catchment area of Par (=420km2)

A Hoz G&D = Catchment area at Hoz G&D Site

The details of non-monsoon peak flows thus arrived at project site have been given in Table

5-22 below:

Table 5-22: Details of Non-Monsoon Flood Peaks at Par

Year Peak Flood at Hoz G&D Site

(cumec)

Peak Flood at Par Site (cumec)

Hoz G&D Site peak transposed to Par

(cumec)

Final Inst. Peak at diversion site

(cumec)

1986-87 132.00 - 81.16 93.33

1987-88 198.00 - 121.74 140.00

1988-89 249.00 - 153.09 176.06

1989-90 218.00 - 134.03 154.14

1990-91 485.00 - 298.19 342.92

1991-92 235.00 - 144.49 166.16

1992-93 205.00 - 126.04 144.95

1993-94 600.00 - 368.90 424.24

1994-95 287.00 - 176.46 202.93

1995-96 228.00 - 140.18 161.21

1996-97 228.50 - 140.49 161.56

2005-06 83.77 - 51.51 59.23

2006-07 192.76 - 118.51 136.29

2007-08 149.26 - 91.77 105.53

2012-13 - 113.28 - 130.27



161133-40ER-0007-00 5-44

Statistical Parameters

The detail of important statistical parameters for the annual instantaneous flood peaks at the

project site is given in Table 5-23 below:

Table 5-23: Detailed Statistics

S.No. Parameter Value Log Transformed

Value

1. Mean 173.25 5.04

2. Variance 8747.2 0.224

3. Standard Deviation 93.526 0.473

4. Skewness 1.83520 0.34746

5. Kurtosis 3.46301 1.43995

Outlier and Randomness Check

A. Outlier Check

Outliers are data points which depart significantly from the trend of the remaining data of the

sample. The high outlier and low outlier tests for the data series has been carried out as

follows:

High outlier threshold: Qh = exp (Xh)

Low outlier threshold: QL = exp (XL)

where,

X h= High outlier threshold in log units

X L= Low outlier threshold in log units

X m= Mean of the log transformed series

Sx = Standard deviation of the log transformed series

Kn = Outliers test K values for 10 % significance level for a Normal distribution.

The data series will have no outlier if,

Qh > Maximum of Observed Series

Ql < Minimum of Observed Series

xnmh SKXX

xnmL SKXX



161133-40ER-0007-00 5-45

Using the above equations, the high outlier and low outlier tests have been carried out, the

details of which are given in the Table 5-24 below:

Table 5-24: Outlier Test for Annual Peak Flow

Parameters Value

Mean(Xm) 5.04

SD (Sx) 0.473

Variance 0.224

Skewness 0.34746

Kurtosis 1.43995

No. of Data 15

Kn 2.247

High outlier threshold Xh 449.26

Low outlier threshold Xl 53.60

Maximum Value 424.24

Minimum Value 59.23

Check on High Outlier OK

Check on Low Outlier OK

From the above table it is seen that there is no outlier in the flood peak values.

B. Randomness Check

The sequence and chance of a variable occurring in a probabilistic process is assumed to

follow a definite probability distribution in which the variables are considered to be purely

random. In a random process, the value of the variate does not depend on the previous or

the next value i.e., all the values occur purely by chance.

For the present project, the randomness has been checked based on the number of peaks

and troughs in the data series.

The randomness check has been performed as follows:

þ =

If, þ < 1.96, the series is random at 5% significance level.

)var(

)(

p

pEP



161133-40ER-0007-00 5-46

where,

P = number of turning points i.e., total number of peaks and troughs in the series = 11

E (p) = 2/3(N-2) = 8.67

Var(p) = (16N-29)/90 = 2.34

N= no. of data points = 15

Hence, þ = 1.52

The þ value is less than 1.96 and hence it can be inferred that the data series are

independent of one another and the variables does not depend on previous or next value.

Flood Frequency Analysis

The flood frequency analysis has been carried out in order to estimate the flood of the

different return periods by method of moments (MOM) adopting following distributions:

(i) Gumbel Distribution

(ii) Log Normal Distribution

(iii) Log Pearson Type III Distribution

The results of the analysis is shown in Table 5-25 and subsequent Figure 5-25 below:

Table 5-25: 25 Year Non-Monsoon Return Period Flood at Hoz

S.No. Distribution Estimated Observed

1 Log Pearson Type-III 375

424.24 2 Log-Normal 355

3 Gumbel 419

The result of the flood frequency analysis has been shown graphically in the figure below:



161133-40ER-0007-00 5-47

0

200

400

600

800

1000

0.0010.0100.1001.000

Probability

Flo

w (

m3 /s

)

1 10 100 1000

Return Period

Observed Data Points

Log Normal

Log Pearson Type-III

Gumbel Prob. Distribution

Lower Confidence Limit

Upper Confidence Limit

Figure 5-25: Plot of Non-Monsoon Flood Frequency Analysis

From the above table and as per BIS criteria, the flood value of 424.24m3/s say 424m3/s is

adopted for planning of diversion works during construction.

5.4.6 Tail Rating Curves

A Rating curve is a graph of discharge versus stage for a given point on a stream and it is

usually plotted as stage on x-axis versus discharge on y-axis.

For the present project at different location, river cross section has been developed by

AutoCAD software. From developed sections wetted area and wetted perimeter has been

calculated for different water depths. To calculate the discharge for different depth of flow,

Manning’ equation is applied.

Manning’s equation, Velocity V = 2

1

3

2

xS)R(xn

1

Discharge Q = A x V



161133-40ER-0007-00 5-48

Tail Rating Curve at Spillway Location

Average river slope at barrage location = 1 in 56

Manning’s roughness coefficient (By Golubtsov Equation)

n = 0.222 x (So)0.33

n = 0.222 x (1/56)0.33

n = 0.058

Considering the actual river condition at project site, it is proposed to consider the Manning’s

roughness coefficient as 0.05.

A. Stage Discharge Curve at 50m Downstream of Barrage Axis

Table 5-26: Stage Discharge Computation at 50m Downstream of Barrage Axis

Elevation Area (A) Perimeter

(P) Depth of flow (h)

Hydraulic Radius (R)

Velocity (V)

Discharge (Q)

m m2 m m m m/sec m3/sec

823.35 0.00 0.00 0.00 0.000 0.00 0

823.50 0.21 2.80 0.15 0.076 0.48 0.10

824.00 8.90 35.31 0.65 0.252 1.07 9

824.50 27.47 39.36 1.15 0.698 2.10 58

825.00 47.99 43.39 1.65 1.106 2.86 137

825.50 70.45 47.39 2.15 1.487 3.48 245

826.00 94.82 51.38 2.65 1.846 4.02 381

826.50 120.85 54.48 3.15 2.218 4.55 549

827.00 148.28 57.71 3.65 2.569 5.01 743

827.50 177.27 61.23 4.15 2.895 5.43 962

828.00 207.87 64.75 4.65 3.210 5.82 1209

828.50 239.84 67.30 5.15 3.564 6.24 1495

829.00 272.96 70.18 5.65 3.889 6.61 1804

829.50 307.44 73.25 6.15 4.197 6.95 2138

830.00 343.28 76.33 6.65 4.497 7.28 2500

830.50 380.40 79.00 7.15 4.815 7.62 2899

831.00 418.69 81.67 7.65 5.127 7.95 3327

831.50 458.15 84.49 8.15 5.423 8.25 3779

832.00 498.92 87.46 8.65 5.705 8.53 4257

832.50 540.97 90.35 9.15 5.988 8.81 4767



161133-40ER-0007-00 5-49

Stage Discharge Curve (50m D/s of Barrage)

822.00

824.00

826.00

828.00

830.00

832.00

834.00

0 1000 2000 3000 4000 5000 6000

Discharge (cumec)

Ele

vati

on

(m

)

Figure 5-26: Stage Discharge Curve at 50m Downstream of Barrage Axis

B. Stage Discharge Curve at 100m Downstream of Barrage Axis

Table 5-27: Stage Discharge Computation at 100m Downstream of Barrage Axis

Elevation Area (A)

Perimeter (P)

Depth of flow (h)


Velocity (V) Discharge

(Q) m m2 m m m m/sec m3/sec

822.50 4.78 20.20 1.00 0.00 0 0 823.00 15.97 25.27 1.50 0.632 1.968 31 823.50 29.38 29.01 2.00 1.013 2.695 79 824.00 44.51 32.29 2.50 1.378 3.310 147 824.50 60.70 34.06 3.00 1.782 3.929 238 825.00 77.59 35.82 3.50 2.166 4.474 347 825.50 95.18 37.59 4.00 2.532 4.965 473 826.00 113.46 39.35 4.50 2.884 5.415 614 826.50 134.02 47.22 5.00 2.838 5.357 718 827.00 158.41 54.87 5.50 2.887 5.419 858 827.50 186.50 62.35 6.00 2.991 5.548 1035 828.00 218.47 73.40 6.50 2.976 5.530 1208 828.50 255.51 80.16 7.00 3.188 5.789 1479 829.00 295.77 86.52 7.50 3.419 6.065 1794 829.50 339.02 92.65 8.00 3.659 6.346 2151 830.00 385.24 98.79 8.50 3.900 6.622 2551 830.50 433.92 102.86 9.00 4.218 6.978 3028 831.00 484.45 106.48 9.50 4.550 7.338 3555 831.50 536.64 109.98 10.00 4.879 7.689 4126 832.00 590.43 113.47 10.50 5.204 8.025 4738 832.50 645.56 115.68 11.00 5.580 8.408 5428



161133-40ER-0007-00 5-50

Stage Discharge Curve (100m D/s of Barrage)

822.00

824.00

826.00

828.00

830.00

832.00

834.00

0 1000 2000 3000 4000 5000 6000

Discharge (cumec)

Ele

vati

on

(m

)

Figure 5-27: Stage Discharge Curve at 100m Downstream of Barrage Axis

Tail Rating Curve at Tailrace Location

Average river slope at barrage location = 1 in 50

Manning’s roughness coefficient (By Golubtsov Equation)

n = 0.222 x (So)0.33

n = 0.222 x (1/50)0.33

n = 0.060

Considering the actual river condition at project site, it is proposed to consider the Manning’s

roughness coefficient as 0.05.



161133-40ER-0007-00 5-51

Table 5-28: Stage Discharge Computation at Tailrace Location

Elevation Area (A) Perimeter

(P) Depth of flow (h)


Velocity (V)

Discharge (Q)

m m2 m m m m/sec m3/sec

629.50 6.67 23.55 0.45 0.283 1.22 8

630.00 20.38 31.18 0.95 0.654 2.13 43

630.50 73.19 112.10 1.45 0.653 2.13 156

631.00 129.51 114.26 1.95 1.133 3.07 398

631.50 186.80 116.48 2.45 1.604 3.88 724

632.00 245.14 118.87 2.95 2.062 4.58 1123

632.50 304.37 120.56 3.45 2.525 5.24 1596

633.00 364.22 122.21 3.95 2.980 5.86 2134

633.50 424.73 123.86 4.45 3.429 6.43 2732

634.00 485.89 125.52 4.95 3.871 6.97 3388

634.50 547.67 127.08 5.45 4.310 7.49 4102

635.00 610.02 128.57 5.95 4.745 7.99 4872

635.50 672.93 130.08 6.45 5.173 8.46 5693

Stage Discharge Curve (At TRC Outfall)

629.50

630.50

631.50

632.50

633.50

634.50

635.50

636.50

0 1000 2000 3000 4000 5000 6000

Discharge (cumec)

Ele

vati

on

(m

)

Figure 5-28: Stage Discharge Curve at Tailrace Channel Location



161133-40ER-0007-00 5-52

5.5 Sedimentation Study

The sedimentation studies for “run-of–the-river” scheme is generally not warranted as no

large storage is planned behind the structure i.e., the ratio of storage vs. mean annual inflow

at the site is negligible. The gross storage at FRL is about 1.17 MCM (refer section

Reservoir Elevation-Area-Capacity) and the mean annual inflow is 770.5 MCM. Thus the

ratio is only 0.0015.

Further, the spillway crest level is kept at riverbed and accumulated sediment infront of

intake will be flushed out by gate opening. The intake crest is kept sufficiently above the

riverbed to withdraw relatively clear water from reservoir. To remove the particles of 0.2mm

and above, desilting basins are provided. Suspended particles entered through intake will be

settled down in surface desilting basin. Hence, sedimentation study is not required for

Par hydroelectric project.

5.5.1 Reservoir Elevation-Area-Capacity

The reservoir elevation-area-capacity curves have been prepared from the contour map of

the reservoirs. The area enclosed within the contours has been evaluated using AutoCAD.

The volume between any two elevations is calculated using the cone formula:

2121*3 AAAAHV

Where,

V = Volume between two contours

H = Contour interval

A1 = Area at level of first contour

A2 = Area at level of second contour



161133-40ER-0007-00 5-53

Table 5-29: Area-Capacity Value

Elevation (m)

Area (Sqm)

Area (Hect.)

Volume (m3)

Cumulative Volume (m3)

Cumulative Volume (MCM)

824 0.00 0.00 0 0 0.00

826 6488.68 0.65 4326 4326 0.00

828 12611.98 1.26 18765 23090 0.02

830 17807.96 1.78 30271 53361 0.05

832 25280.54 2.53 42871 96232 0.10

834 34216.91 3.42 59272 155505 0.16

836 42620.05 4.26 76683 232188 0.23

838 53167.52 5.32 95593 327781 0.33

840 62676.41 6.27 115714 443495 0.44

842 71557.53 7.16 134136 577631 0.58

844 85589.04 8.56 156937 734568 0.73

845 94439.47 9.44 89978 824546 0.82

846 103289.91 10.33 98832 923378 0.92

848 144353.02 14.44 246500 1169878 1.17

850 196840.12 19.68 339839 1509717 1.51

Figure 5-29: Elevation-Area-Capacity Curve



161133-40ER-0007-00 5-54

5.6 References

1. Bureau of Indian Standards, Indian Standard No. IS 11223-1985, “Guidelines for

Fixing Spillway Capacity”.

2. Bureau of Indian Standards, Indian Standard No. IS 14815-2000, “Design Flood for

River Diversion Works – Guidelines”.

3. Flood Estimation Report for North Brahmaputra Basin-Subzone 2(a), Hydrology

Directorate, CWC, New Delhi, 1991.

4. Manual on Estimation of Design Flood, CWC, New Delhi, March-2001.

5. Guide to Hydrological Practices, “WMO No-168”, 5th Edition, 1994.

6. Pre Feasibility Report-Par Hydroelectric Project, KVK Energy and Infrastructure Pvt.

Ltd.



161133-40ER-0007-00

Annexure 5-1 Rainfall Data

Par Hydroelectric Project (52 MW)Detailed Project Report


Annexure 5-1

Date Aug sept oct Nov Dec Jan Feb Mar Apr May June July Aug sept oct Nov Dec Jan Feb Mar Apr May June July Aug sept oct Nov Dec Jan Feb Mar Apr May June July Aug sept oct Nov Dec Jan Feb Mar

1 0.00 5.21 3.81 0.00 0.00 0.00 0.00 0.00 4.57 7.37 0.00 28.96 0.00 0.00 32.00 0.00 0.00 3.81 0.00 0.00 34.54 0.00 1.27 17.53 22.86 9.91 22.35 0.00 0.00 0.00 0.00 7.37 5.59 0.00 60.71 10.67 5.84 33.27 0.00 0.00 0.00 0.00 2.54 9.65

2 3.81 12.83 15.75 0.00 0.00 0.00 0.00 0.00 5.08 22.61 0.00 18.80 43.18 0.00 36.83 0.00 0.00 3.05 0.00 0.00 17.02 2.29 7.11 15.24 19.56 28.96 30.48 0.00 0.00 0.00 0.00 0.00 0.00 0.00 15.75 3.30 1.78 32.00 0.00 0.00 0.00 0.00 2.29 17.27

3 0.00 19.05 9.40 0.00 0.00 3.81 0.00 0.00 3.81 5.33 7.62 9.14 0.00 0.00 5.84 0.00 0.00 1.27 0.00 3.05 6.60 5.84 0.00 11.68 8.89 7.11 16.00 0.00 0.00 0.00 3.05 0.00 3.81 2.79 29.46 1.52 0.51 74.42 0.00 0.00 0.00 0.00 0.00 16.51

4 0.00 9.53 22.10 3.81 0.00 0.00 0.00 9.91 3.30 0.00 3.05 6.86 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6.35 4.06 4.57 2.79 34.29 0.00 36.83 3.05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 44.45 0.00 8.89 18.29 0.00 0.00 0.00 0.00 0.00 8.38

5 0.00 13.21 14.73 17.02 0.00 0.00 0.00 1.52 6.10 0.00 54.61 28.96 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.52 0.00 0.00 26.16 10.16 0.00 5.59 10.16 1.78 0.00 0.00 0.00 2.54 0.00 0.00 10.16 28.45 81.53 21.59 0.00 0.00 0.00 0.00 0.00 9.40

6 0.00 1.40 10.92 0.00 0.00 0.00 0.00 0.00 4.83 0.00 0.00 3.05 0.00 0.00 0.00 0.00 0.00 0.00 27.43 4.06 0.00 0.00 33.78 58.17 4.57 42.67 23.88 10.69 0.00 0.00 1.27 3.30 0.00 0.00 9.40 48.01 35.31 0.00 0.00 0.00 0.00 0.00 0.00 13.97

7 0.00 0.00 9.91 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 7.37 0.00 0.00 0.00 0.00 0.00 0.00 6.60 0.00 0.00 0.00 24.89 26.67 3.81 2.29 7.11 7.37 0.00 0.00 4.06 4.06 1.02 16.25 3.81 19.56 70.36 4.57 0.00 0.00 0.00 0.00 3.56 12.70

8 9.14 17.78 7.24 0.00 0.00 0.00 0.00 0.00 0.00 0.00 43.18 22.10 45.47 0.00 0.00 0.00 0.00 0.00 8.12 0.00 15.75 12.45 17.02 30.99 6.86 15.24 0.00 3.81 0.00 0.00 0.00 0.00 8.13 23.60 30.99 31.50 4.83 7.37 0.00 0.00 0.00 0.00 0.00 6.10

9 0.00 16.64 12.70 0.00 16.51 0.00 0.00 0.00 3.81 0.00 4.57 29.97 11.18 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 30.48 24.64 2.29 28.70 15.49 0.00 1.27 0.00 0.00 0.00 4.57 4.06 0.00 49.53 0.00 13.97 0.00 0.00 0.00 0.00 0.00 Nil

10 0.00 19.05 0.00 0.00 0.00 0.00 0.00 18.54 5.33 0.00 2.29 19.30 77.47 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 10.67 28.96 44.70 26.67 48.01 0.00 3.56 0.00 0.00 2.29 8.89 73.15 8.89 27.43 7.11 2.54 0.00 0.00 0.00 0.00 0.00 Nil

11 0.00 15.75 6.99 0.00 0.00 16.51 0.00 9.65 4.06 24.13 15.75 17.78 53.34 0.00 0.00 0.00 0.00 0.00 1.27 8.12 0.00 0.00 7.62 3.81 11.43 0.00 43.18 0.00 0.00 0.00 0.00 2.79 0.00 17.78 5.84 61.47 7.87 2.03 0.00 0.00 0.00 7.87 0.00 Nil

12 0.00 6.86 9.78 0.00 0.00 11.43 0.00 0.00 16.76 0.00 9.14 29.46 0.00 5.08 0.00 17.27 0.00 0.00 5.59 3.81 0.00 0.00 45.46 33.53 0.00 0.00 6.35 0.00 0.00 0.00 0.00 0.00 2.29 61.21 5.08 2.79 0.00 0.00 0.00 0.00 0.00 10.16 0.00 Nil

13 0.00 0.00 0.00 0.00 0.00 9.40 0.00 0.00 0.00 0.00 9.65 6.86 0.00 0.00 4.32 19.05 0.00 0.00 0.00 9.91 2.29 0.00 19.05 15.75 33.58 0.00 0.00 0.00 0.00 4.32 0.00 0.00 17.27 26.67 0.00 17.53 0.00 6.10 0.00 0.00 0.00 0.00 8.89 Nil

14 11.43 15.75 0.00 0.00 0.00 7.11 0.00 0.00 5.33 0.00 83.31 36.83 0.00 0.00 7.37 0.00 0.00 0.00 0.00 23.62 14.48 4.06 10.41 9.65 43.18 6.10 0.00 0.00 0.00 2.29 0.00 0.00 41.15 32.25 11.18 0.00 2.29 0.00 0.00 0.00 0.00 0.00 5.59 Nil

15 10.41 14.99 7.62 8.89 0.00 19.05 0.00 0.00 0.00 0.00 21.59 0.00 0.00 35.56 1.27 0.00 0.00 0.00 0.00 2.79 0.00 14.22 8.13 16.00 50.29 6.35 0.00 0.00 0.00 0.00 0.00 0.00 27.43 43.18 7.11 87.88 15.49 0.00 0.00 0.00 0.00 0.00 5.08 Nil

16 4.06 15.49 0.00 0.00 0.00 4.57 0.00 0.00 7.37 0.00 19.56 0.00 0.00 21.84 0.00 0.00 0.00 0.00 0.00 2.29 0.00 40.39 0.00 34.29 32.77 8.13 0.00 1.27 0.00 0.00 0.00 0.00 5.08 53.34 2.54 56.13 3.81 0.00 0.00 0.00 0.00 0.00 8.38 Nil

17 3.56 9.40 0.00 0.00 0.00 0.00 0.00 0.00 9.65 0.00 4.57 0.00 0.00 33.02 0.00 0.00 0.00 0.00 0.00 5.08 0.00 7.37 54.86 31.50 37.59 30.23 0.00 0.00 0.00 0.00 0.00 0.00 3.05 20.57 0.00 9.65 0.00 0.00 0.00 0.00 0.00 0.00 0.00 15.75

18 11.68 9.53 0.00 0.00 0.00 0.00 0.00 0.00 17.02 0.00 30.73 0.00 22.86 0.00 2.54 0.00 9.91 0.00 0.00 0.00 2.79 18.29 9.91 24.64 39.37 46.99 0.00 0.00 0.00 4.83 0.00 0.00 6.35 14.22 13.97 10.67 0.00 0.00 0.00 0.00 0.00 0.00 0.00 9.14

19 3.18 6.86 0.00 0.00 0.00 0.00 0.00 0.00 9.91 17.53 19.56 19.56 54.61 0.00 28.70 9.14 3.05 0.00 0.00 16.26 12.19 0.00 0.00 4.57 19.05 16.76 0.00 2.79 0.00 0.00 0.76 0.00 46.23 41.65 22.61 67.06 0.00 7.87 0.00 0.00 0.00 0.00 0.00 5.08

20 3.94 11.81 0.00 0.00 0.00 0.00 0.00 0.00 23.37 7.37 88.39 83.57 36.83 0.00 18.03 7.37 1.27 0.00 0.00 21.84 16.51 3.30 24.13 6.35 9.40 55.88 0.00 4.06 0.00 0.00 7.87 20.83 22.86 0.00 44.70 2.03 6.60 1.78 0.00 0.00 0.00 0.00 0.00 3.56

21 2.29 12.83 0.00 0.00 0.00 8.89 0.00 0.00 8.89 0.00 4.06 94.49 0.00 0.00 6.60 14.22 0.00 0.00 0.00 6.35 19.81 15.24 6.60 0.00 18.29 28.19 0.00 18.29 0.00 0.00 1.78 6.35 0.00 9.65 69.09 5.08 8.13 5.08 0.00 0.00 18.54 0.00 0.00 8.89

22 2.54 16.51 0.00 0.00 0.00 0.00 0.00 12.45 4.83 9.65 7.11 40.64 0.00 16.51 0.00 0.00 1.78 0.00 0.00 3.56 5.59 31.50 13.97 0.00 34.04 2.03 0.00 0.00 0.00 0.00 0.00 14.75 35.81 29.21 83.82 0.00 0.00 17.78 0.00 0.00 3.05 0.00 0.00 19.56

23 12.95 0.00 0.00 0.00 0.00 0.00 0.00 0.00 16.51 0.00 0.00 34.29 0.00 62.23 0.00 0.00 0.00 0.00 0.00 1.52 13.97 3.30 11.43 0.00 45.72 0.76 0.00 0.00 0.00 0.00 0.00 4.06 32.26 33.78 40.13 0.00 0.00 28.70 0.00 0.00 0.00 0.00 0.00 2.29

24 13.97 12.83 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 48.77 14.22 91.44 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 30.48 7.37 29.97 12.19 0.00 0.00 0.00 2.76 0.00 5.33 2.54 24.64 32.77 0.00 31.50 9.65 0.00 0.00 0.00 8.89 0.00 13.46

25 4.83 19.56 0.00 0.00 0.00 0.00 16.51 4.06 0.00 0.00 42.67 28.70 0.00 69.85 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.52 2.29 8.38 3.81 5.84 0.00 0.00 4.32 5.59 0.00 38.61 10.16 32.00 21.08 12.19 51.56 11.43 0.00 0.00 0.00 3.81 1.52 Nil

26 3.30 16.51 0.00 0.00 0.00 0.00 0.00 0.00 8.89 4.57 0.00 2.54 8.89 54.61 0.00 0.00 0.00 0.00 9.65 0.00 21.59 30.48 7.11 12.45 1.27 7.62 6.86 0.00 0.00 0.00 0.00 1.27 0.00 15.75 27.94 6.35 45.47 14.99 0.00 0.00 0.00 0.00 12.70 Nil

27 13.21 9.65 0.00 0.00 0.00 0.00 0.00 0.00 19.56 7.11 17.27 17.78 0.00 9.65 0.00 0.00 0.00 0.00 17.02 0.00 9.10 2.29 21.59 35.56 34.54 10.92 4.06 3.81 0.00 0.00 8.13 1.52 0.00 1.52 8.89 0.00 48.77 2.54 0.00 0.00 0.00 0.00 0.00 8.13

28 7.87 8.13 0.00 0.00 0.00 0.00 0.00 4.06 10.41 0.00 8.13 16.00 0.00 10.16 0.00 0.00 0.00 0.00 0.00 0.00 0.00 57.66 43.69 43.94 32.51 21.59 7.62 6.86 0.00 0.00 11.94 0.00 9.40 2.54 16.26 35.56 4.06 11.94 0.00 0.00 0.00 0.00 0.00 3.81

29 3.94 0.00 0.00 0.00 0.00 0.00 5.59 0.00 0.00 3.56 9.14 0.00 52.04 0.00 0.00 0.00 0.00 0.00 0.00 27.69 46.74 36.07 28.96 4.32 0.00 0.76 9.65 0.00 16.51 0.00 0.00 0.00 47.50 43.94 0.00 4.57 0.00 0.00 0.00 0.00 3.05

30 0.00 0.00 0.00 0.00 0.00 4.06 7.11 5.33 0.00 19.56 0.00 6.34 45.72 0.00 0.00 0.00 0.00 20.57 0.00 0.00 55.12 43.18 44.45 36.58 0.00 0.00 1.52 0.00 0.00 0.00 0.00 33.53 1.78 21.08 0.00 0.00 0.00 0.00 0.00 Nil

31 0.00 0.00 0.00 5.08 0.00 0.00 12.19 0.00 0.00 0.00 0.00 3.81 0.00 34.54 59.18 0.00 0.00 0.00 0.00 17.02 0.00 29.97 0.00 0.00 0.00 10.16

Total 126.11 317.16 130.95 29.72 16.51 89.91 16.51 72.89 204.72 105.67 519.93 673.11 374.39 507.71 143.50 67.05 16.01 8.13 75.68 144.51 196.29 282.46 572.76 659.91 722.94 504.45 244.60 61.49 20.32 19.79 55.37 115.07 293.89 596.83 707.66 640.08 492.76 332.48 0.00 0.00 21.59 30.73 50.55 196.86

2002-03 2003-04

ONE DAY RAINFALL DATA IN (mm) OF LEPORIANG SITE ON THE DIKRONG (AUG 2001-FEB2005)

2004-052001-02

161133-40ER-0007-00 Page 1 of 4



Annexure 5-1

Date Aug sept oct Nov Dec Jan Feb Mar Apr May June July Aug sept oct Nov Dec Jan Feb Mar Apr May June July Aug sept oct Nov Dec Jan Feb Mar Apr May June July Aug sept Mar

1 0.00 49.59 3.81 41.91 0.00 0.00 0.00 0.00 8.89 15.24 0.00 35.56 0.00 0.00 58.42 0.00 0.00 0.00 0.00 0.00 16.76 0.00 14.48 29.94 16.51 6.60 20.07 0.00 0.00 0.00 0.00 6.60 0.00 0.00 61.46 8.38 4.06 23.37 10.16

2 3.81 10.16 33.02 34.29 0.00 0.00 0.00 0.00 17.78 6.35 0.00 17.78 39.37 0.00 16.51 0.00 0.00 0.00 0.00 0.00 11.43 16.51 2.54 18.54 5.84 17.27 33.78 0.00 0.00 0.00 0.00 0.00 1.78 0.00 41.91 2.29 2.79 26.67 14.22

3 0.00 0.00 40.64 5.08 0.00 0.00 0.00 29.21 2.54 0.00 0.00 8.89 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3.30 7.62 5.84 10.16 0.00 7.62 11.94 0.00 0.00 0.00 3.56 0.00 4.57 0.00 27.18 0.00 0.00 58.17 13.46

4 0.00 0.00 22.86 0.00 0.00 0.00 0.00 20.32 0.00 0.00 45.72 6.35 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.32 5.08 29.46 46.99 40.64 0.00 16.26 2.54 0.00 0.00 0.00 0.00 0.00 0.00 0.00 22.35 0.00 6.86 33.78 Nil

5 0.00 5.08 16.51 0.00 0.00 0.00 0.00 0.00 8.89 0.00 11.43 27.94 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.27 23.88 5.08 0.00 8.13 9.14 0.00 0.00 0.00 0.00 0.76 0.00 0.00 9.14 25.15 51.82 15.49 6.86

6 0.00 10.16 1.27 0.00 0.00 0.00 0.00 0.00 16.51 2.54 5.08 3.81 0.00 0.00 0.00 0.00 0.00 0.00 2.54 2.29 0.00 7.62 3.30 54.86 0.00 17.53 18.03 9.14 0.00 0.00 2.29 6.68 0.00 0.76 18.29 40.13 22.61 3.81 15.24

7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 54.61 5.08 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 7.62 0.00 19.81 0.00 4.32 3.30 8.13 1.78 0.00 5.33 0.00 0.00 33.53 7.62 16.25 49.53 3.05 9.14

8 2.54 44.45 0.00 0.00 3.81 0.00 0.00 0.00 2.54 0.00 0.00 22.86 43.18 0.00 0.00 0.00 1.53 1.27 0.00 0.00 9.91 0.00 0.00 20.07 3.81 26.67 10.67 2.03 0.76 0.00 0.00 0.00 5.08 20.07 15.49 30.00 3.56 9.14 Nil

9 0.00 4.57 6.35 0.00 1.27 0.00 15.24 7.62 7.62 0.00 0.00 31.75 7.62 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3.56 0.00 0.00 27.43 0.00 17.27 35.56 0.00 0.00 0.00 0.00 0.00 3.05 1.52 10.92 35.81 0.00 16.26 Nil

10 0.00 0.00 2.54 0.00 0.00 10.16 3.81 0.00 1.27 3.81 0.00 7.62 69.85 0.00 0.00 0.00 0.00 0.00 0.00 0.00 10.41 21.08 0.00 24.64 29.97 23.11 35.06 0.00 0.00 0.00 0.00 0.51 6.60 53.34 6.35 22.61 10.16 5.08 Nil

11 0.00 0.00 0.00 0.00 0.00 11.43 1.27 29.21 29.21 45.72 0.00 10.16 48.26 0.00 0.00 0.00 0.00 0.00 0.00 2.54 0.00 0.00 0.00 0.00 6.35 0.00 8.13 0.00 0.00 0.00 0.00 4.83 0.00 24.64 72.64 6.60 6.35 Nil

12 0.00 0.00 4.57 0.00 0.00 3.81 0.00 1.27 10.16 5.08 5.08 29.21 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.06 20.07 0.00 29.21 33.02 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 31.24 7.37 0.00 0.00 4.06 Nil

13 0.00 16.51 1.27 0.00 0.00 0.00 0.00 20.32 0.00 10.16 80.01 7.62 0.00 0.00 0.00 21.34 0.00 0.00 6.10 11.68 0.00 0.00 35.56 4.57 41.91 1.78 0.00 0.00 0.00 6.07 0.00 0.76 11.68 29.21 10.16 9.40 0.00 1.78 Nil

14 1.78 0.00 0.00 0.00 0.00 0.00 0.00 15.24 0.00 0.00 83.82 34.29 0.00 0.00 35.31 0.00 0.00 0.00 0.00 6.10 0.00 0.00 17.27 20.83 45.21 4.32 0.00 0.00 0.00 3.30 0.00 0.00 33.53 14.73 6.86 0.00 0.00 0.00 Nil

15 3.30 7.62 0.00 0.00 0.00 0.00 0.00 0.00 2.54 0.00 10.16 0.00 0.00 29.21 15.24 0.00 0.00 0.00 0.00 0.00 7.87 0.00 45.72 3.81 62.23 8.89 0.00 0.00 0.00 0.00 0.00 0.00 28.19 18.29 8.38 64.52 18.29 0.00 Nil

16 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 22.86 0.00 3.81 0.00 0.00 19.05 0.00 0.00 0.00 0.00 0.00 2.79 3.81 0.00 29.97 43.94 40.64 11.94 0.00 0.00 0.00 0.00 0.00 0.00 2.29 59.69 0.00 32.77 14.48 0.00 Nil

17 16.51 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3.81 29.21 3.81 0.00 0.00 30.48 0.00 0.00 0.00 0.00 0.00 3.81 6.60 0.00 8.89 22.86 35.56 43.69 0.00 0.00 0.00 1.27 0.00 0.00 2.54 23.88 0.00 5.59 3.05 0.00 13.97

18 1.27 20.32 0.00 0.00 0.00 0.00 0.00 0.00 1.27 1.27 0.00 0.00 16.51 0.00 0.00 0.00 0.00 0.00 0.00 1.27 0.00 0.00 5.84 16.51 32.26 27.94 0.00 0.00 0.00 1.78 0.00 0.00 0.00 0.00 22.35 8.38 0.00 2.29 10.16

19 4.57 13.97 0.00 0.00 0.00 0.00 0.00 0.00 0.00 22.86 0.00 26.67 55.88 0.00 0.00 0.00 0.00 0.00 0.00 21.84 10.67 36.83 0.00 26.67 0.00 17.53 0.00 3.30 0.00 0.00 0.00 0.00 24.13 14.22 18.03 38.61 0.00 16.51 Nil

20 0.00 15.24 0.00 0.00 0.00 0.00 0.00 0.00 43.18 3.81 0.00 78.74 34.29 0.00 0.00 7.37 0.00 0.00 7.62 10.16 7.87 21.08 2.54 0.00 0.00 47.75 0.00 5.08 0.00 0.00 6.60 9.40 17.78 15.24 62.48 4.32 0.00 4.83 8.13

21 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6.35 2.29 0.00 0.00 95.25 0.00 0.00 4.06 4.32 0.00 0.00 0.00 3.05 21.59 23.37 61.72 0.00 21.59 24.13 0.00 17.27 0.00 0.00 2.79 10.41 0.00 1.78 45.21 1.52 11.18 2.03 5.08

22 53.34 0.00 0.00 0.00 0.00 0.00 0.00 2.54 16.51 0.00 0.00 36.83 0.00 13.97 0.00 11.43 0.00 0.00 0.00 2.29 3.56 7.62 21.08 0.00 44.96 3.81 0.00 0.00 0.00 0.00 0.00 7.62 9.91 44.45 93.73 0.76 0.00 11.68 12.70

23 18.54 0.00 0.00 0.00 0.00 3.81 0.00 0.00 10.16 13.97 3.81 40.64 0.00 58.42 0.00 0.00 0.00 0.00 0.00 0.00 0.00 27.94 0.00 0.00 54.61 5.84 0.00 0.00 0.00 1.27 0.00 24.89 24.89 18.03 31.50 0.00 0.00 21.34 6.10

24 29.21 0.00 0.00 0.00 0.00 11.43 0.00 13.97 0.00 10.16 5.08 45.72 1.27 86.36 0.00 0.00 0.00 0.00 0.00 0.00 6.89 3.30 0.00 0.00 15.24 14.48 0.00 0.00 0.00 4.57 0.00 1.27 2.03 7.62 36.83 0.00 19.56 7.11 16.51

25 46.99 3.81 0.00 0.00 27.94 7.62 0.00 11.43 0.00 67.31 40.64 30.48 0.00 67.31 0.00 0.00 0.00 0.00 4.32 0.00 7.62 0.00 43.18 0.00 8.38 0.00 0.00 4.83 6.35 0.00 40.39 3.81 41.91 17.78 10.41 42.93 13.72 Nil

26 21.59 2.54 0.00 0.00 34.29 0.00 0.00 2.54 13.97 33.02 60.96 7.62 5.08 45.72 0.00 0.00 0.00 0.00 13.72 0.00 0.00 3.81 3.81 29.21 0.00 7.37 3.56 0.00 0.00 1.02 0.00 1.02 0.00 9.14 0.00 0.00 24.89 11.94 9.91

27 0.00 0.00 0.00 0.00 5.08 0.00 0.00 13.97 0.00 12.70 3.81 16.51 0.00 3.81 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.32 24.89 45.72 5.08 5.08 2.54 0.00 0.00 0.00 0.00 0.00 6.10 9.14 0.00 43.43 4.32 2.54

28 41.91 0.00 0.00 0.00 0.00 0.00 0.00 5.08 2.54 41.91 0.00 17.78 0.00 5.08 0.00 0.00 3.81 0.00 0.00 0.00 3.81 0.00 46.23 21.08 36.83 16.51 5.84 6.10 0.00 0.00 4.06 0.00 0.00 4.57 22.10 39.37 20.07 7.62 10.16

29 0.00 0.00 0.00 3.81 0.00 0.00 8.89 0.00 0.00 0.00 6.35 0.00 21.59 0.00 0.00 13.97 16.51 0.00 0.00 7.11 29.21 29.97 29.21 16.76 0.00 0.00 3.81 0.00 5.08 0.00 0.00 0.00 16.76 27.69 0.00 0.00 2.79

30 0.00 2.54 0.00 0.00 0.00 0.00 1.27 8.89 0.00 0.00 0.00 0.00 43.18 0.00 0.00 0.00 1.52 14.48 0.00 27.94 43.94 40.64 43.94 22.61 0.00 0.00 0.00 0.00 0.00 0.00 0.00 46.23 1.27 29.21 0.00 Nil

31 0.00 0.00 0.00 0.00 6.35 0.00 11.43 0.00 0.00 0.00 0.00 5.08 7.62 32.77 37.59 0.00 0.00 0.00 0.00 0.00 2.03 34.54 7.37

Total 245.36 206.56 132.84 85.09 72.39 48.26 20.32 195.58 233.43 325.12 417.83 662.94 321.31 424.18 129.54 44.46 19.31 19.30 34.30 95.76 160.81 257.80 482.34 645.12 649.98 433.59 202.70 53.59 11.18 25.63 29.71 115.14 181.86 473.96 675.62 499.90 419.62 310.40 174.50

ONE DAY RAINFALL DATA IN (mm) OF LOPTOP SITE ON THE DIKRONG (AUG 2001-SEPT2004)

2001-02 2002-03 2003-04 2004-05

161133-40ER-0007-00 Page 2 of 4



Annexure 5-1

Date Aug sept oct Nov Dec Jan Feb Mar Apr May June July Aug sept oct Nov Dec Jan Feb Mar Apr May June July Aug sept oct Nov Dec Jan Feb Mar Apr May June July Aug sept oct Nov Dec Jan Feb Mar

1 0.00 5.08 0.00 0.00 0.00 0.00 0.00 0.00 8.89 15.24 0.00 43.18 0.00 0.00 25.40 0.00 0.00 0.00 0.00 0.00 14.48 0.00 5.33 18.54 21.59 16.76 7.62 0.00 0.00 0.00 0.00 8.38 0.00 0.00 17.27 9.91 0.00 27.94 0.00 0.00 0.00 0.00 0.76 Nil

2 13.97 13.46 13.97 0.00 0.00 0.00 0.00 0.00 15.24 5.08 0.00 15.24 13.97 0.00 33.02 0.00 0.00 1.27 0.00 0.00 15.24 3.81 10.16 12.19 4.57 18.29 16.51 0.00 0.00 0.00 0.00 0.00 11.18 0.00 9.65 6.86 2.79 45.72 0.00 0.00 0.00 0.00 0.00 6.86

3 2.54 13.21 26.67 0.00 0.00 0.00 0.00 7.62 2.54 0.00 5.08 10.16 5.08 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.06 2.54 0.00 10.16 0.00 11.94 19.05 0.00 0.00 0.00 0.00 0.00 6.35 4.06 19.05 0.00 0.00 56.39 5.59 0.00 0.00 0.00 0.00 9.91

4 0.00 8.89 0.00 7.62 0.00 0.00 0.00 12.70 0.00 0.00 2.03 5.08 28.45 0.00 0.00 0.00 0.00 0.00 0.00 5.08 2.54 3.81 0.00 19.30 0.00 33.27 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 28.96 0.00 4.31 3.81 22.10 0.00 0.00 0.00 0.00 11.94

5 0.00 4.57 16.51 8.89 0.00 0.00 0.00 0.00 8.89 0.00 55.88 16.51 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3.05 1.27 8.38 20.83 0.00 1.52 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 12.19 46.23 35.05 18.28 16.76 0.00 0.00 0.00 0.00 0.76

6 0.00 8.13 13.21 0.00 0.00 0.00 0.00 0.00 16.51 2.29 5.08 5.08 0.00 0.00 0.00 0.00 0.00 0.00 23.37 14.73 0.00 0.00 3.81 19.05 0.00 28.19 13.46 15.24 0.00 0.00 0.00 1.02 0.00 2.03 17.78 42.93 26.67 1.78 24.89 0.00 0.00 0.00 0.00 Nil

7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.54 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 23.62 36.32 1.52 0.00 2.54 9.91 0.00 0.00 2.03 0.00 0.00 13.46 0.00 26.92 40.64 2.79 30.23 0.00 0.00 0.00 0.00 Nil

8 0.00 13.21 0.00 0.00 15.24 0.00 0.00 0.00 0.00 0.00 40.04 27.94 0.00 0.00 0.00 0.00 0.00 0.00 5.08 0.00 16.26 0.00 13.97 34.29 0.00 16.51 0.00 2.54 0.00 0.00 0.00 0.00 13.21 0.00 20.83 35.81 13.97 3.81 20.83 0.00 0.00 0.00 0.00 Nil

9 0.00 0.00 10.16 0.00 13.97 0.00 0.00 0.00 15.24 0.00 0.00 34.29 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 15.24 15.24 27.94 43.69 19.30 5.59 0.00 0.00 0.00 0.00 0.00 11.68 13.97 0.00 24.13 0.00 5.08 48.26 0.00 0.00 0.00 0.00 Nil

10 0.00 10.16 0.00 0.00 0.00 0.00 0.00 0.00 10.16 5.08 0.00 0.00 33.02 2.54 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3.81 18.03 37.08 22.86 35.31 29.46 0.00 2.54 0.00 0.00 0.00 17.78 60.96 9.14 43.69 4.06 0.76 8.13 0.00 0.00 0.00 0.00 0.76

11 0.00 1.27 0.00 0.00 0.00 0.00 0.00 0.00 2.54 22.86 33.02 7.62 86.87 0.00 0.00 0.00 0.00 0.00 0.00 3.56 0.00 0.00 5.08 19.05 21.59 0.00 24.13 0.00 0.00 0.00 0.00 4.32 0.00 52.32 3.81 39.88 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.51

12 0.00 0.00 0.00 0.00 0.00 0.00 0.00 12.70 16.51 25.40 13.97 29.21 17.53 0.00 0.00 0.00 0.00 0.00 3.05 0.00 0.00 0.00 19.30 23.11 14.99 0.00 4.06 0.00 0.00 0.00 0.00 0.00 4.32 26.67 10.92 7.37 0.00 2.03 0.00 0.00 0.00 0.00 2.03 Nil

13 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 10.16 7.62 10.16 10.16 0.00 0.00 17.78 0.00 0.00 0.00 9.40 0.00 0.00 35.56 9.65 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 23.37 0.00 10.92 0.00 0.76 0.00 0.00 0.00 0.00 2.03 Nil

14 0.00 13.97 0.00 0.00 0.00 0.00 0.00 2.54 5.08 0.00 81.28 33.02 8.13 0.00 0.00 12.45 0.00 0.00 0.00 5.08 7.62 0.00 36.07 5.59 30.23 6.10 0.00 0.00 0.00 3.30 0.00 0.00 24.13 25.90 2.29 0.00 4.83 0.00 8.89 0.00 0.00 0.00 0.76 Nil

15 0.00 3.81 7.62 0.00 0.00 0.00 0.00 0.00 0.00 2.54 33.02 0.00 0.00 29.46 0.00 0.00 0.00 0.00 0.00 0.00 6.60 0.00 14.48 11.93 30.23 2.54 0.00 0.00 0.00 0.00 0.00 0.00 0.00 27.94 9.40 37.08 0.00 0.00 52.83 0.00 0.00 0.00 0.76 Nil

16 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 21.59 0.00 2.54 0.00 0.00 22.86 0.00 0.00 0.00 0.00 0.00 1.27 0.00 38.35 2.54 0.00 24.89 4.06 0.00 0.00 0.00 0.00 0.76 0.00 18.29 19.30 5.08 40.39 0.00 0.00 2.79 0.00 0.00 0.00 0.00 Nil

17 15.75 13.21 0.00 0.00 0.00 2.54 0.00 2.54 5.08 10.16 3.81 0.00 8.38 20.32 7.62 0.00 0.00 0.00 0.00 7.11 0.00 7.62 5.59 0.00 17.78 46.23 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.51 15.75 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Nil

18 2.54 22.10 0.00 0.00 0.00 2.54 0.00 0.00 2.54 0.00 35.56 0.00 16.00 0.00 1.27 0.00 0.00 0.00 0.00 0.00 0.00 22.06 20.57 28.45 42.16 41.15 0.00 0.00 0.00 3.05 0.00 0.00 0.00 0.00 17.53 4.32 0.00 0.00 0.00 0.00 0.00 0.00 0.00 10.92

19 3.30 12.70 0.00 0.00 0.00 3.81 0.00 0.00 7.62 20.32 2.54 29.21 53.34 0.00 17.78 0.00 1.27 0.00 0.00 11.43 13.97 0.00 0.00 1.78 24.13 10.92 0.00 0.00 0.00 0.00 0.00 0.00 2.54 19.30 22.61 28.70 0.00 5.33 0.00 0.00 0.00 0.00 0.00 Nil

20 2.54 10.16 0.00 0.00 0.00 0.00 0.00 0.00 48.26 48.26 67.31 68.58 17.02 0.00 17.78 5.84 0.00 0.00 0.00 9.65 5.08 0.00 42.67 8.13 33.53 71.12 0.00 4.57 0.00 0.00 3.30 12.19 0.00 0.00 34.54 20.83 9.14 0.00 0.00 0.00 0.00 0.00 0.00 13.46

21 3.81 0.00 0.00 0.00 0.00 2.29 0.00 0.00 7.62 3.81 2.54 96.52 1.78 0.00 0.00 11.68 2.03 0.00 0.00 15.75 14.99 10.92 0.00 8.89 19.05 13.97 0.00 12.19 0.00 0.00 0.00 1.02 0.00 34.29 57.91 7.37 2.54 6.86 0.00 0.00 0.00 0.00 0.00 1.78

22 20.83 0.00 0.00 0.00 0.00 0.00 7.62 0.00 15.24 5.59 6.35 35.56 0.00 0.00 0.00 0.00 0.00 0.00 0.00 10.67 0.00 22.86 0.00 0.00 1.27 7.11 0.00 0.00 0.00 0.00 0.00 6.60 14.22 14.22 67.56 0.00 0.00 13.97 0.00 0.00 9.65 0.00 0.00 8.13

23 16.51 3.81 0.00 0.00 0.00 0.00 0.00 12.70 10.16 2.54 0.00 40.64 0.00 28.70 0.00 0.00 0.00 0.00 0.00 0.00 0.00 7.62 3.81 0.00 6.86 0.00 0.00 0.00 0.00 0.00 0.76 16.00 15.24 19.05 35.81 0.00 0.00 12.70 0.00 0.00 0.00 0.00 0.00 2.29

24 10.16 0.00 0.00 0.00 0.00 4.57 0.00 0.00 0.00 0.00 0.00 43.18 0.00 17.53 0.00 0.00 0.00 0.00 0.00 0.00 15.75 0.00 47.24 0.00 36.83 10.16 0.00 0.00 0.00 1.52 0.00 13.46 0.00 16.51 40.13 0.00 20.82 13.97 0.00 0.00 0.00 0.00 0.00 14.22

25 10.67 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 53.34 43.18 33.02 0.00 30.99 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.79 3.05 2.79 6.35 1.27 0.00 0.76 3.05 0.00 36.32 0.00 27.94 16.00 8.38 27.94 9.40 0.00 0.00 0.00 0.00 0.00 1.27

26 9.91 0.00 0.00 0.00 0.00 0.00 12.70 7.62 10.16 35.05 0.00 12.70 4.32 4.32 0.00 0.00 0.00 0.00 2.54 0.00 0.00 25.91 7.11 0.00 0.00 1.78 0.00 0.00 0.51 0.00 0.00 1.52 0.00 14.22 12.45 4.57 55.88 11.43 0.00 0.00 0.00 0.00 1.52 5.33

27 2.54 0.00 0.00 0.00 0.00 0.00 0.00 2.54 0.00 7.62 15.24 15.24 0.00 7.62 0.00 0.00 0.00 0.00 10.16 0.00 0.00 7.62 11.43 60.45 9.14 17.27 3.81 2.54 0.00 0.00 0.00 0.00 0.00 0.00 13.46 0.00 13.72 0.00 1.52 0.00 0.00 0.00 2.03 3.81

28 9.65 0.00 0.00 0.00 0.00 0.00 0.00 2.54 2.54 41.91 5.08 17.78 0.00 9.65 0.00 0.00 0.00 0.00 0.00 0.00 7.37 15.24 15.24 6.60 5.08 35.31 6.60 9.14 0.00 0.00 5.59 0.00 0.00 0.00 15.49 0.00 29.97 9.91 1.27 0.00 0.00 0.00 0.00 2.03

29 0.00 0.00 0.00 0.00 0.00 0.00 5.08 0.00 0.00 27.94 5.08 0.00 2.54 0.00 0.00 0.00 0.00 0.00 0.00 0.00 19.30 33.02 6.35 14.22 0.00 0.00 5.84 0.00 14.73 0.00 0.00 35.46 21.59 29.21 1.27 1.78 0.00 0.00 0.00 0.00 0.51

30 0.00 0.00 0.00 0.00 0.00 0.00 2.54 7.62 0.00 10.16 0.00 0.00 10.16 0.00 0.00 0.00 2.54 17.27 0.00 0.00 41.15 74.17 16.26 15.24 0.00 0.00 0.00 0.00 0.00 1.78 0.00 33.02 0.00 19.81 0.00 0.00 0.00 0.00 0.00 Nil

31 0.00 0.00 0.00 0.00 0.00 0.00 15.24 0.00 0.00 0.00 0.00 5.59 0.00 39.37 15.24 0.00 0.00 0.00 0.00 0.00 4.06 2.54 0.00 0.00 0.00 0.76

Total 124.72 157.74 88.14 16.51 29.21 15.75 20.32 71.12 240.03 317.25 499.27 652.78 304.05 186.69 102.87 47.75 3.30 3.81 44.20 116.59 127.01 188.69 428.47 568.94 452.63 484.62 134.10 56.13 9.65 10.92 27.17 100.83 140.72 450.97 554.98 495.31 315.95 254.50 244.09 0.00 9.65 0.00 9.89 95.25

2001-02 2002-03 2003-04 2004-05

ONE DAY RAINFALL DATA IN (mm) OF SANGALEE SITE ON THE DIKRONG (AUG 2001-FEB2005)

161133-40ER-0007-00 Page 3 of 4



Annexure 5-1

Date Nov Dec Jan Feb Mar Apr May June July Aug sept oct Nov Dec Jan Feb Mar Apr May June July Aug sept oct Nov Dec Jan Feb Mar Apr May June July Aug sept oct Nov Dec Jan Feb

1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 9.14 19.05 7.11 0.00 16.51 0.00 0.00 0.00 0.00 0.00 13.97 0.00 1.78 19.30 0.00 5.84 25.15 0.00 0.00 0.00 0.00 9.65 7.87 0.00 42.83 7.62 4.83 71.88 0.00 0.00 0.00 0.00 0.00

2 0.00 0.00 0.00 0.00 0.00 10.16 1.02 0.00 15.75 15.75 0.00 5.33 0.00 0.00 1.02 0.00 0.00 5.59 11.68 4.06 45.97 0.00 21.34 12.19 0.00 0.00 0.00 0.00 0.00 0.00 21.84 20.83 0.00 0.51 54.61 0.00 0.00 0.00 0.00 0.00

3 0.00 0.00 0.00 0.00 0.00 2.03 0.00 4.83 31.24 19.05 0.00 2.03 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5.59 2.54 0.00 25.40 13.97 0.00 0.00 0.00 0.76 0.00 3.05 0.00 33.02 0.00 0.00 16.00 0.00 0.00 0.00 0.00 0.00

4 0.00 0.00 0.00 0.00 18.03 3.30 6.10 6.86 9.65 44.05 0.00 0.00 0.00 0.00 0.00 0.00 3.56 4.06 4.06 29.21 57.91 0.00 55.63 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.06 32.00 0.00 6.35 4.06 24.13 0.00 0.00 0.00 0.00

5 18.20 14.73 0.00 0.00 2.79 0.00 0.00 79.28 15.75 40.64 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.57 17.78 7.87 0.00 0.00 17.78 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.06 20.32 71.12 8.89 5.08 0.00 0.00 0.00 0.00

6 0.00 18.54 0.00 0.00 0.00 0.00 2.29 2.29 2.03 0.00 0.00 0.00 0.00 0.00 0.00 9.65 0.00 0.00 0.00 1.27 3.05 0.00 47.50 23.88 13.72 0.00 0.00 0.00 4.32 0.00 32.51 14.99 36.07 44.70 3.81 35.56 0.00 0.00 0.00 6.86

7 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5.84 0.00 0.00 0.00 0.00 0.00 0.00 8.64 0.00 0.00 0.00 28.19 38.86 0.00 0.00 0.00 11.18 0.00 0.00 4.06 0.00 0.00 0.00 2.03 25.91 77.72 31.50 49.53 0.00 0.00 0.00 0.00

8 0.00 0.00 0.00 0.00 0.00 0.00 0.00 50.04 25.91 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.27 5.84 10.16 9.40 20.32 0.00 6.86 0.00 9.40 0.00 0.00 0.00 0.00 6.35 0.00 27.94 23.88 0.00 11.43 26.92 0.00 0.00 0.00 0.00

9 0.00 0.00 0.00 0.00 0.00 52.32 0.00 1.52 48.77 1.27 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5.84 0.00 61.21 14.99 15.75 12.70 0.00 0.00 0.00 0.00 0.00 2.79 31.75 1.02 26.42 0.00 0.00 41.66 0.00 0.00 0.00 0.00

10 0.00 0.00 0.00 0.00 0.00 11.43 0.00 0.76 2.79 3.81 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 33.27 1.52 9.65 58.40 0.00 0.00 0.00 0.00 0.00 10.16 81.28 11.94 25.40 3.05 0.00 0.00 0.00 0.00 0.00 0.00

11 0.00 0.00 0.00 0.00 0.76 10.67 40.89 15.24 28.45 135.89 0.00 0.00 0.00 0.00 0.00 0.00 1.52 0.00 0.00 0.00 10.16 3.56 0.00 30.48 0.00 0.00 0.00 0.00 0.00 0.00 77.47 5.08 61.72 2.54 0.00 0.00 0.00 0.00 0.00 0.00

12 0.00 0.00 0.00 0.00 3.05 7.62 32.00 18.29 26.92 23.37 48.77 0.00 0.00 0.00 0.00 5.08 2.54 8.13 0.00 28.49 40.13 19.81 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.76 21.08 16.00 6.35 0.00 0.00 0.00 0.00 0.00 0.00 0.00

13 0.00 0.00 0.00 0.00 0.00 0.25 0.00 0.00 8.38 13.97 0.00 0.00 11.94 0.00 0.00 2.54 13.72 7.37 0.00 29.21 7.11 12.70 0.00 0.00 0.00 0.00 0.00 0.00 0.00 20.32 64.00 0.00 6.60 0.00 0.00 0.00 0.00 0.00 0.00 30.23

14 0.00 0.00 0.00 0.00 2.29 0.00 0.00 106.17 10.16 6.60 0.00 0.00 17.78 0.00 0.00 0.00 3.56 3.05 0.00 25.15 34.29 0.00 6.86 0.00 0.00 0.00 13.46 0.00 0.00 45.72 49.78 0.00 0.00 0.00 0.00 10.16 0.00 0.00 0.00 7.37

15 0.00 0.00 0.00 0.00 0.00 0.00 3.81 25.91 0.76 7.62 40.39 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 8.13 27.94 105.16 0.00 0.00 0.00 3.81 6.10 0.00 0.00 18.54 41.15 8.13 62.74 8.13 0.00 57.15 0.00 0.00 0.00 8.13

16 0.00 0.00 1.27 0.00 0.00 4.57 0.00 20.57 0.00 0.76 54.10 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.79 20.32 56.64 2.54 0.00 0.00 0.00 0.00 0.00 0.00 5.08 26.16 11.43 68.83 0.00 0.00 2.29 0.00 0.00 0.00 12.70

17 0.00 0.00 0.00 0.00 0.00 3.56 0.00 6.35 0.00 65.02 34.04 0.00 0.00 0.00 0.00 0.00 1.78 6.35 2.79 1.52 23.37 65.02 61.98 0.00 0.00 0.00 0.00 0.00 0.00 2.29 0.00 0.00 2.29 0.00 0.00 0.00 0.00 0.00 0.00 0.00

18 0.00 0.00 0.00 0.00 0.00 38.10 0.00 44.45 0.00 33.02 0.00 4.06 0.00 0.00 0.00 0.00 6.64 0.51 0.00 12.70 13.97 32.51 41.91 0.00 0.00 0.00 0.00 0.00 0.00 8.13 0.00 19.30 3.05 0.00 0.00 0.00 0.00 0.00 0.00 0.00

19 0.00 0.00 19.81 0.00 0.00 17.78 5.59 31.75 14.22 43.94 0.00 13.46 0.00 0.00 0.00 0.00 16.26 0.00 0.00 0.00 25.40 6.60 2.03 0.00 9.14 0.00 16.51 0.00 0.00 1.52 36.07 29.21 43.18 0.00 1.27 0.00 0.00 0.00 0.00 0.00

20 0.00 0.00 0.00 0.00 0.00 23.37 23.62 89.41 12.19 23.62 0.00 0.00 9.40 0.00 0.00 0.51 8.89 6.35 0.00 56.90 17.78 75.69 41.66 0.00 6.86 0.00 0.00 6.35 14.47 0.00 1.27 47.75 54.10 2.79 0.00 0.00 0.00 0.00 6.86 0.00

21 0.00 0.00 0.00 4.06 0.00 1.78 22.86 6.35 32.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.02 12.45 12.45 5.33 4.83 56.64 4.57 0.00 16.76 0.00 0.00 0.00 20.57 0.00 16.51 73.66 13.97 4.32 0.00 0.00 0.00 0.00 6.86 0.00

22 0.00 0.00 0.00 6.35 0.00 17.02 7.37 4.83 67.56 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 14.48 14.99 0.00 0.00 0.00 8.13 0.00 2.54 0.00 0.00 0.00 9.14 31.75 12.19 88.39 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

23 19.05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 95.25 0.00 45.72 0.00 0.00 0.00 0.00 0.00 0.00 6.35 5.84 6.35 5.84 30.48 0.00 0.00 0.00 0.00 0.00 0.00 13.72 26.67 26.16 33.02 0.00 0.00 17.78 0.00 0.00 0.00 0.00 0.00

24 0.00 0.00 0.00 0.00 0.00 1.02 1.78 0.00 78.49 0.00 41.91 0.00 0.00 0.00 0.00 0.00 0.00 0.00 26.67 44.96 0.00 0.00 0.00 0.00 0.00 0.00 2.54 0.00 15.49 0.00 2.03 29.72 0.00 3.05 0.00 0.00 0.00 0.00 0.00 0.00

25 0.00 0.00 14.22 0.00 1.27 0.00 0.00 59.69 21.08 3.05 29.46 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 7.87 0.00 12.19 7.87 0.00 0.00 0.00 0.00 0.00 32.00 0.00 29.21 14.22 6.86 38.86 23.88 0.00 0.00 0.00 0.00 0.00

26 0.00 0.00 13.46 4.57 4.83 1.27 30.73 0.00 0.00 24.64 0.00 0.00 0.00 0.00 0.00 2.79 0.00 3.81 93.98 20.32 0.00 0.00 15.24 1.27 0.00 0.00 0.00 0.00 0.00 0.00 11.18 17.27 0.00 57.66 7.87 0.00 0.00 0.00 0.00 0.00

27 0.00 0.00 2.28 0.00 18.54 17.53 47.75 26.16 7.62 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 27.94 71.63 19.81 40.13 19.56 0.00 7.11 0.00 0.00 0.00 1.27 0.00 0.00 6.35 0.00 45.72 6.86 0.00 0.00 0.00 0.00 0.00

28 0.00 0.00 0.00 4.83 1.53 8.64 49.53 4.06 15.24 0.00 13.97 0.00 0.00 0.00 0.00 2.29 0.00 2.29 32.77 13.97 2.29 2.79 36.83 4.32 19.05 0.00 0.00 13.46 0.00 0.00 0.00 17.78 58.17 0.00 0.00 0.76 0.00 0.00 0.00 0.00

29 0.00 0.00 0.00 11.93 1.52 0.00 18.03 0.00 0.00 25.15 0.00 0.00 0.00 0.00 0.00 0.00 1.02 39.11 23.11 0.00 9.91 0.00 0.00 0.00 0.00 20.83 0.00 0.00 28.96 30.73 34.54 0.00 27.94 0.00 0.00 0.00 0.00

30 0.00 0.00 0.00 2.29 13.72 31.75 21.84 0.00 0.00 18.03 0.00 0.00 11.21 0.00 12.45 8.38 0.00 24.13 58.42 16.76 33.27 0.00 0.00 0.00 0.00 0.00 0.00 0.00 48.77 35.56 29.46 3.81 0.00 0.00 0.00 0.00

31 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.57 0.00 34.04 48.51 0.00 0.00 0.00 0.00 0.00 3.05 16.00 0.00 0.00 0.00

Total 37.25 33.27 51.04 19.81 67.31 247.66 307.09 653.82 595.10 513.18 351.54 41.39 39.12 11.21 1.02 31.50 77.78 108.98 254.76 495.84 659.11 601.70 480.33 200.14 95.76 3.81 38.61 45.46 120.63 191.00 614.66 687.47 626.63 416.81 291.59 253.24 0.00 0.00 13.72 65.29

2002-2003 2004-052001-02 2003-04

ONE DAY RAINFALL DATA IN (mm) OF JAMPA SITE ON THE DIKRONG (NOV 2001-FEB2005)

161133-40ER-0007-00 Page 4 of 4



161133-40ER-0007-00

Annexure 5-2 Discharge Data of Pare Dam Site,

Hoz G&D Site and Par G&D Site



Annexure 5-2

CA of PARE = 824 sqkm

1978-79 1979-80 1980-81 1981-82 1982-83 1983-84 1984-85 1985-86 1986-87 1987-88 1988-89 1989-90 1990-91 1991-92 1992-93 1993-94 1994-95 1995-96 1996-97 1997-98 1998-99 1999-00 2000-01 2001-02 2002-03 2003-04 2004-05

I 55.06 14.06 41.63 21.58 36.34 38.28 25.11 79.11 53.62 111.41 143.28 58.98 90.13 76.21 32.58 95.43 157.32 48.23 66.08 89.96 71.09 62.05 63.99 74.69 95.18 95.18 45.72

II 85.07 51.26 84.69 23.10 96.98 67.31 65.92 67.18 79.41 94.90 142.05 125.45 51.51 88.80 33.52 105.41 63.82 83.76 43.93 108.53 105.27 50.90 98.53 65.41 122.98 122.98 53.30

III 175.19 52.87 63.21 37.63 136.37 55.58 54.26 53.40 133.32 115.81 153.94 43.96 118.90 98.13 98.46 138.58 80.06 99.63 105.72 89.75 108.94 42.78 108.67 72.25 78.93 63.35 173.59

I 102.94 202.67 55.69 53.36 40.39 87.53 71.43 249.96 38.15 168.88 197.14 55.42 69.73 103.13 59.09 91.07 109.35 184.60 105.30 79.92 100.82 86.33 77.99 41.10 148.12 86.10 118.01

II 81.79 75.26 94.74 90.40 37.15 36.40 54.46 76.40 69.86 124.35 168.70 93.13 88.81 88.89 107.73 62.20 53.98 160.15 115.45 90.19 102.65 88.87 88.53 65.21 117.76 63.10 127.53

III 72.22 78.22 38.78 46.50 61.31 50.81 85.13 117.98 91.94 163.08 224.97 132.03 89.55 62.34 111.83 56.41 55.34 86.03 74.36 73.67 94.25 82.01 58.96 82.94 242.90 71.61 85.55

I 66.59 44.26 51.26 43.68 30.06 29.33 36.89 56.68 121.04 123.91 35.75 55.86 57.23 78.18 87.31 59.12 56.84 69.30 64.94 75.43 91.03 60.35 100.93 75.21 114.61 69.46 69.76

II 72.02 43.49 61.87 54.40 24.97 27.96 38.04 37.97 74.00 168.95 45.17 58.88 56.74 85.12 60.24 70.39 73.47 109.78 102.34 85.72 107.35 82.03 79.28 58.59 107.62 67.49 46.47

III 51.12 73.21 39.68 48.63 28.15 47.16 64.81 65.79 106.38 188.57 118.14 91.40 70.53 74.21 74.90 66.67 69.88 70.79 73.85 67.28 91.17 93.52 64.83 110.64 83.33 59.58 43.90

I 56.06 103.32 27.35 36.34 22.87 48.56 77.99 65.68 72.10 167.44 57.17 53.48 52.44 84.52 41.74 74.41 52.83 86.33 72.04 66.57 89.33 96.16 75.52 93.47 58.46 78.04 70.13

II 89.88 75.69 26.44 38.83 74.30 122.11 242.28 37.92 135.37 152.84 45.92 93.85 74.98 69.63 43.99 63.04 63.84 60.96 60.24 82.13 71.44 74.26 83.28 88.23 53.39 54.15 45.44

III 71.31 36.77 36.88 30.16 55.02 59.43 56.12 50.80 81.57 221.12 50.50 77.53 105.45 68.15 42.64 70.20 57.31 94.37 87.06 81.52 73.82 56.33 72.93 73.22 68.52 48.86 40.13

I 55.78 77.54 20.81 30.11 24.39 30.57 35.96 34.89 75.95 157.23 45.81 68.35 98.12 45.97 32.98 65.63 45.21 63.81 79.05 62.94 65.96 82.28 47.65 95.76 62.47 48.23 105.40

II 42.40 42.30 17.44 21.35 20.67 70.56 41.04 71.76 73.96 80.72 29.73 73.32 78.78 64.11 59.91 56.85 63.62 56.68 55.29 47.37 61.17 85.05 28.60 71.28 46.79 51.46 55.11

III 29.73 27.26 21.58 21.35 24.16 34.29 35.34 64.44 84.10 35.97 55.27 49.75 48.96 40.40 33.64 58.40 35.26 51.94 64.28 42.91 71.24 96.92 23.91 51.00 42.88 34.38 33.16

I 34.06 22.15 31.72 19.43 18.77 24.21 23.18 52.58 53.24 27.39 23.92 46.60 35.31 31.26 22.95 32.20 43.39 47.31 56.95 40.33 58.25 65.31 21.16 46.71 35.36 26.92 23.09

II 28.58 22.53 28.91 18.01 18.25 22.08 21.48 46.36 44.09 23.47 21.17 41.66 30.01 26.67 21.34 25.70 33.41 51.86 49.32 38.95 52.56 61.51 23.01 40.32 37.61 19.57 20.79

III 35.11 25.44 19.63 17.20 17.25 19.77 19.57 42.21 37.33 21.71 22.31 29.55 25.04 23.31 19.46 24.83 30.92 31.62 49.36 37.57 49.91 50.03 21.35 36.20 27.32 17.60 16.11

I 19.63 26.01 19.02 16.78 17.01 18.74 18.89 39.74 35.10 19.89 20.21 21.50 18.55 21.45 19.94 24.56 33.15 29.37 39.32 35.65 44.79 43.69 11.23 35.76 22.30 16.18 12.97

II 16.30 20.96 18.53 22.39 17.53 17.82 19.62 38.77 34.85 20.18 18.98 18.75 20.14 19.17 15.63 25.08 29.73 30.47 36.19 28.60 39.53 34.90 10.98 35.46 19.39 11.62 11.33

III 16.58 22.49 19.86 18.43 18.77 20.83 19.71 41.88 35.91 20.51 20.23 24.41 20.72 23.40 15.45 24.72 26.84 28.32 32.45 32.00 35.38 26.76 12.04 24.03 20.37 8.62 10.91

I 13.91 19.91 18.91 16.67 16.10 17.29 18.03 37.22 31.19 18.21 17.54 18.64 18.55 17.34 19.96 23.55 26.98 23.83 31.28 30.64 31.61 24.10 11.23 21.32 18.82 7.77 12.26

II 13.11 19.58 17.48 16.78 15.72 17.95 17.54 35.95 30.12 18.07 18.19 18.25 16.14 17.11 21.52 24.28 26.77 24.74 27.41 31.68 28.66 23.37 10.98 20.04 15.15 8.67 9.89

III 14.77 22.68 19.54 18.01 18.01 19.77 18.74 38.37 31.44 19.51 19.66 23.34 16.35 17.37 17.56 23.22 26.99 24.32 25.85 31.35 25.54 23.84 12.04 22.21 14.21 11.58 9.66

I 14.67 19.68 17.44 16.53 15.44 16.93 17.38 36.57 37.10 18.31 17.60 27.42 14.55 16.90 14.98 23.02 25.54 22.43 27.37 30.77 23.54 24.64 10.53 15.68 16.95 9.05 10.74

II 12.77 19.97 17.20 19.25 15.10 16.66 17.52 35.43 36.76 18.42 21.48 25.94 20.59 18.31 35.99 23.17 33.66 22.33 29.04 30.97 21.38 24.35 10.04 15.06 14.94 9.30 17.95

III 10.10 18.39 14.44 13.20 12.63 14.72 18.17 27.85 35.53 17.76 18.16 28.65 15.46 15.90 14.47 23.23 28.03 23.44 26.73 34.88 20.48 25.61 12.76 14.86 16.10 12.45 18.29

I 12.30 26.06 17.05 17.62 15.10 18.47 25.78 34.07 42.56 21.13 20.08 29.83 15.92 69.33 14.76 26.87 29.48 22.76 24.54 33.73 19.89 31.44 11.74 16.09 15.10 15.73 22.03

II 12.20 21.39 20.87 17.10 17.34 27.28 15.44 41.84 64.43 30.20 24.25 30.04 20.59 27.94 22.83 30.98 25.43 44.66 57.75 32.41 17.26 30.71 11.07 29.01 31.39 10.52 25.10

III 13.43 21.20 22.06 20.44 18.96 22.82 22.18 36.06 64.67 24.75 28.69 38.76 18.82 42.49 24.11 48.96 25.12 26.95 42.24 50.57 16.48 27.58 23.09 35.27 23.16 36.60 27.23

I 15.29 21.20 24.34 27.15 17.48 31.93 23.66 34.37 88.09 24.77 34.73 34.49 45.84 27.32 16.37 50.74 27.32 23.92 53.14 51.37 18.68 36.55 23.17 118.34 41.24 21.61 17.71

II 14.29 22.19 23.82 28.15 19.39 25.87 28.88 62.44 70.57 33.19 22.83 52.15 20.19 46.97 30.74 24.21 32.99 31.58 41.22 64.59 16.14 32.67 14.16 114.52 53.15 53.03 14.80

III 16.96 54.31 19.91 29.25 30.11 21.61 26.02 69.77 94.24 28.79 20.86 69.73 21.71 27.43 21.88 46.73 30.18 34.80 31.61 41.26 49.28 57.57 50.94 82.44 42.96 31.13 19.39

I 30.68 38.20 21.78 29.82 68.40 23.94 41.87 82.49 79.41 38.73 26.77 43.07 88.20 33.82 68.58 28.00 43.10 84.55 43.55 39.00 59.53 63.06 36.11 46.59 27.95 22.33 19.86

II 36.63 40.01 24.63 23.59 49.34 80.99 27.22 71.72 75.06 111.06 16.35 52.30 63.16 52.74 47.88 29.48 43.69 92.21 46.64 36.01 48.10 23.82 29.60 51.10 21.08 76.54 29.24

III 16.53 30.92 31.40 16.87 34.10 66.01 74.06 63.15 88.22 216.60 30.25 44.57 43.87 37.72 33.32 34.61 76.67 63.31 73.06 53.79 70.13 78.75 56.15 58.78 49.87 66.55 26.72

1317.149 1345.568 991.0011 895.5127 1038.312 1187.823 1320.264 1845.501 2111.478 2515.257 1748.64 1629.276 1528.725 1527.857 1268.755 1536.713 1523.685 1850.358 1769.656 1709.157 1804.873 1717.559 1312.874 1757.64 1773.63 1325.153 1304.053

1598 1633 1203 1087 1260 1442 1602 2240 2562 3052 2122 1977 1855 1854 1540 1865 1849 2246 2148 2074 2190 2084 1593 2133 2152 1608 1583

PERIOD

Jun

Aug

Mar

Apr

Sep

Oct

Nov

Dec

Jul

Jan

Feb

May

Inflow (MCM)

Runoff Depth (mm)

10-DAILY AVERAGE FLOW SERIES AT PARE DAM SITE

161133-40ER-0007-00 Page 1 of 8



Anneuxre 5-2


16.79 19.24 34.44 40.50 117.84 52.07 53.70 30.28 17.53

15.11 18.12 55.91 27.34 114.57 45.24 58.39 29.72 17.24

13.00 16.08 39.33 28.94 111.46 40.02 83.77 28.96 17.20

13.89 18.51 37.36 45.28 190.16 37.95 46.63 27.97 17.24

13.14 19.02 29.15 25.35 144.36 48.19 44.88 27.47 17.05

12.30 27.69 28.14 20.40 446.17 46.29 40.74 27.13 16.57

12.25 21.92 27.48 18.09 521.34 43.53 40.94 26.66 16.44

17.80 18.83 25.12 16.47 522.10 42.87 39.17 25.89 16.38

37.47 17.54 26.41 15.05 218.51 41.44 36.40 25.14 16.06

20.93 16.68 24.16 18.37 161.83 40.44 37.80 24.62 15.68

21.35 25.80 21.46 102.06 89.20 39.23 35.02 24.11 16.66

15.91 19.84 21.24 108.33 56.73 37.36 34.13 23.61 15.69

14.08 31.20 20.71 243.33 46.89 36.56 33.08 23.17 15.50

13.58 18.32 21.42 139.20 40.49 35.69 28.33 22.31 15.36

12.88 33.66 17.65 77.44 38.12 34.10 22.62 22.51 15.26

12.93 21.88 18.18 72.90 40.10 33.86 22.62 22.18 15.18

12.93 20.68 23.72 72.94 32.30 35.07 31.91 24.00 14.94

14.08 34.46 22.47 70.83 30.70 35.23 32.57 25.23 14.77

13.66 21.30 18.59 84.11 28.19 36.03 37.05 29.64 14.74

12.90 57.92 30.56 72.39 39.22 37.42 83.55 23.40 14.42

17.02 36.35 31.09 50.52 148.27 38.20 41.46 22.60 13.27

13.71 28.40 46.48 52.59 190.34 41.02 46.70 21.71 13.04

12.28 20.62 44.17 36.34 230.68 54.27 40.09 22.26 13.31

12.33 20.12 44.01 37.14 135.10 185.05 38.03 20.53 13.52

14.26 19.79 31.52 36.49 276.31 202.59 32.12 20.67 13.43

14.26 20.12 23.36 36.31 216.64 620.76 33.78 23.54 13.24

16.60 19.86 26.93 38.08 212.36 125.56 28.86 28.89 13.34

34.13 26.26 25.88 29.46 166.43 98.34 33.79 25.68 12.69

28.88 29.49 25.95 27.97 79.84 77.17 28.85 18.40 12.53

25.60 20.07 25.57 25.79 64.48 61.72 28.79 18.08 12.45

45.45 34.09 53.46 12.41

17.3 19.4 32.8 25.6 254.8 43.8 48.2 27.4 16.7

14.4 28.5 21.6 104.4 44.2 36.1 36.1 24.0 15.2

18.9 26.0 32.5 36.8 172.0 150.5 35.2 22.2 13.0

16.9 24.7 28.9 55.0 153.7 76.8 39.9 24.5 14.9

Discharge Data of HOZ. G&D Site -Year 2005

Date

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

Ist 10-Daily Avg.

2nd 10-Daily Avg.

3rd 10-Daily Avg.

Monthly Average

161133-40ER-0007-00 Page 2 of 8



Anneuxre 5-2


12.53 10.28 15.14 10.09 10.58 112.84 60.51 44.27 21.17 16.78 11.20 14.21

12.32 10.58 12.08 10.10 13.06 81.78 53.79 42.05 20.42 19.20 11.20 14.00

12.228 10.14 11.37 10.56 12.31 68.07 52.03 34.12 18.83 20.22 11.48 13.89

11.973 10.06 11.19 13.40 16.48 49.93 49.61 29.10 18.22 19.02 11.66 13.81

11.912 10.89 10.95 11.90 23.73 38.28 47.21 25.29 17.37 19.04 11.65 13.62

11.9 10.30 10.80 11.84 33.23 30.59 54.71 22.62 17.14 17.50 11.20 13.61

11.84 10.15 10.38 11.63 33.74 45.95 53.81 20.58 20.58 16.67 11.20 13.22

11.466 10.34 10.19 11.06 23.41 34.94 53.16 34.84 28.40 15.39 11.18 13.22

11.664 10.52 10.19 10.69 18.74 49.65 47.73 28.40 20.07 14.65 11.19 13.01

11.242 10.43 10.18 11.18 17.78 70.78 50.91 25.28 30.84 14.32 11.20 13.02

11.412 10.30 10.09 11.34 23.04 286.38 69.45 21.65 27.39 14.08 11.20 12.80

11.395 10.13 10.10 30.59 22.72 180.40 61.68 21.63 47.51 15.03 11.52 14.63

11.326 10.30 10.21 13.51 57.35 139.33 56.01 18.99 83.21 14.69 11.89 15.08

11.331 10.08 10.19 11.42 46.20 105.07 57.78 47.15 62.89 15.15 15.49 14.29

11.84 11.29 10.09 11.02 28.41 133.72 58.10 20.91 46.97 15.22 14.75 13.95

11.707 10.13 10.14 11.24 23.38 173.02 51.91 19.10 40.16 14.68 14.45 13.76

11.514 11.50 12.96 12.16 20.47 105.43 47.71 17.87 40.12 14.35 14.09 12.87

11.592 10.30 10.66 12.66 19.23 89.78 58.60 27.00 37.30 14.02 13.69 12.39

11.425 10.11 10.52 18.34 18.49 79.50 52.47 18.38 28.42 13.55 12.61 12.11

11.43 10.11 10.18 22.07 17.62 79.64 71.97 17.72 23.97 13.51 11.88 11.89

11.175 20.47 10.47 15.33 14.98 69.16 58.47 23.11 22.05 13.88 11.69 11.77

14.012 22.61 10.17 13.62 13.75 62.95 54.79 17.29 28.97 13.42 11.66 11.80

12.743 18.12 10.20 11.37 17.43 50.31 50.68 19.39 30.68 13.21 36.73 11.79

11.383 19.49 10.21 13.53 20.60 67.07 53.02 43.53 25.85 13.14 31.55 11.80

11.088 18.13 10.44 17.36 16.13 83.03 129.10 81.36 20.63 12.61 26.49 11.76

11.008 18.30 10.21 18.57 13.30 101.36 75.55 46.05 19.99 12.30 20.09 11.65

10.775 27.56 10.14 13.28 59.58 75.95 58.30 32.94 26.69 12.03 18.39 11.64

10.718 18.97 10.05 11.41 64.56 67.64 52.81 25.83 19.83 11.96 17.00 14.91

10.718 10.05 10.54 43.93 66.30 49.93 24.84 17.50 12.10 15.22 18.69

10.442 10.06 10.70 63.93 67.72 46.15 26.44 18.62 11.59 14.29 12.37

10.194 10.07 25.55 11.27

11.9 10.4 11.2 11.2 20.3 58.3 52.3 30.7 21.3 17.3 11.3 13.6

11.5 10.4 10.5 15.4 27.7 137.2 58.6 23.0 43.8 14.4 13.2 13.4

11.3 20.5 10.2 13.6 32.8 71.1 62.9 34.1 23.1 12.5 20.3 12.8

11.6 13.3 10.6 13.4 26.9 88.9 57.9 29.1 29.4 14.7 14.9 13.3


Date

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

Ist 10-Daily Avg.

2nd 10-Daily Avg.

3rd 10-Daily Avg.

Monthly Average

161133-40ER-0007-00 Page 3 of 8



Anneuxre 5-2


11.89 11.62 17.49 14.88 16.451 62.59 65.135 42.93 23.12 17.87

12.15 12.53 16.75 14.47 15.52 104.37 63.418 42.62 22.40 17.65

12.326 12.23 16.41 53.52 14.678 100.84 57.054 41.81 22.35 17.53

12.342 12.51 14.94 46.18 14.274 71.77 49.449 40.71 22.06 17.45

12.616 15.08 14.21 38.52 14.341 60.37 48.198 39.79 21.73 17.26

12.68 14.22 13.28 32.28 14.296 50.45 46.813 38.58 22.19 16.80

12.392 15.85 12.22 28.05 14.333 76.03 45.157 37.24 22.09 16.86

12.29 16.72 13.37 23.56 14.025 88.87 70.067 42.41 22.41 16.20

12.329 25.12 14.12 24.74 15.433 214.21 48.602 56.60 22.08 15.89

12.01 18.97 15.98 21.38 15.048 205.66 46.803 54.08 22.09 15.60

12.031 19.09 20.33 22.33 14.88 178.54 47.841 54.03 21.83 15.16

11.8 20.76 20.82 19.59 35.312 103.02 51.186 44.19 21.46 14.73

11.789 18.63 20.71 20.71 18.606 80.57 56.568 41.35 21.06 17.21

11.819 18.82 21.56 19.45 17.535 178.94 44.163 37.40 21.62 13.88

11.624 18.67 20.35 17.47 26.081 133.04 42.531 149.26 20.83 13.63

11.621 17.61 19.33 18.54 26.328 108.69 157.915 39.06 21.17 13.18

11.592 17.74 17.85 19.96 20.501 119.50 78.574 35.88 20.90 12.46

11.453 16.93 16.99 18.00 18.036 123.49 79.45 87.07 20.00 11.73

11.459 16.08 16.31 16.62 16.909 112.45 75.027 57.35 19.28 11.80

11.457 15.55 17.59 16.35 22.007 98.07 72.599 36.99 19.07 11.94

11.652 15.13 16.31 15.30 18.223 83.63 109.901 31.23 18.55 12.01

11.6 14.75 16.03 23.73 15.753 95.96 80.35 33.83 18.56 12.12

11.817 14.22 15.13 19.43 74.386 115.46 110.336 18.25 18.25 12.36

12.42 13.88 14.15 19.46 192.755 126.52 225.765 28.97 17.81 12.33

12.286 13.29 14.74 18.59 123.867 116.95 131.702 28.87 18.78 12.07

12.016 13.00 14.74 17.20 119.84 103.94 226.745 29.09 17.76 12.11

11.88 18.43 16.02 16.74 92.976 97.90 200.797 28.55 17.60 12.13

11.786 18.67 15.39 17.20 71.84 99.90 199.773 27.41 18.11 12.06

11.677 14.81 16.17 54.497 79.11 182.698 26.11 18.02 12.26

11.625 15.26 17.12 87.568 59.34 210.69 24.70 17.84 12.25

11.609 14.84 77.395 165.569 23.50 12.12

12.3 15.5 14.9 29.8 14.8 103.5 54.1 43.7 22.2 16.9

11.7 18.0 19.2 18.9 21.6 123.6 70.6 58.3 20.7 13.6

11.9 15.2 15.2 18.1 84.5 97.9 167.7 27.3 18.1 12.2

11.9 16.3 16.4 22.3 41.7 108.3 99.7 42.6 20.4 14.2


Date

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

Ist 10-Daily Avg.

2nd 10-Daily Avg.

3rd 10-Daily Avg.

Monthly Average

161133-40ER-0007-00 Page 4 of 8



Anneuxre 5-2


12.416 14.50 20.34 20.451 25.77 156.215 141.387 124.21

12.343 14.70 19.73 28.815 27.37 154.336 140.239 126.35

12.28 14.31 19.40 29.234 26.21 152.277 143.509 135.89

12.285 14.30 19.38 28.95 25.18 154.63 145.242 133.17

12.337 14.33 19.35 23.678 27.50 166.231 143.401 139.30

12.286 14.31 19.21 23.072 26.66 158.406 214.08 138.27

12.262 14.24 19.26 22.006 26.54 153.406 160.663 127.67

12.268 14.38 19.21 21.726 26.93 149.559 162.75 125.18

12.211 15.35 19.14 21.626 25.81 145.254 160.723 126.19

12.268 15.03 19.08 21.6 25.76 142.133 155.772 145.16

14.124 14.77 18.88 21.988 28.52 138.741 225.84 141.14

16.78 14.63 18.74 20.779 36.03 152.692 229.527 138.97

18.016 14.58 20.55 20.216 27.41 185.521 189.656 138.05

16.461 14.77 19.63 19.718 666.94 187.09 168.8 137.61

15.895 15.86 19.40 19.443 364.33 180.788 162.298 132.01

15.28 15.49 19.32 19.219 188.48 159.818 156.441 127.70

14.767 15.43 19.17 19.167 163.90 155.569 153.063 143.51

14.533 14.85 19.55 24.12 147.14 154.988 147.825 140.07

14.232 15.17 19.43 25.113 148.57 160.636 142.103 138.07

13.911 14.74 19.21 22.546 156.28 158.592 136.227 134.84

15.182 14.31 19.30 20.269 146.01 154.63 132.042 129.65

13.997 14.47 19.16 21.359 153.81 152.768 125.602 126.92

13.054 14.56 18.93 25.793 180.18 156.982 119.348 127.99

14.216 14.41 19.62 25.076 155.10 154.727 113.942 124.40

13.167 15.16 19.73 26.647 145.05 155.676 114.74 117.63

13.348 15.93 21.17 22.952 140.33 152.392 110.466 115.25

13.803 15.51 20.60 21.85 135.86 147.282 110.166 113.19

13.243 15.02 23.45 23.996 138.01 145.044 113.727 109.68

12.89 15.17 22.25 55.845 138.56 142.586 117.391 104.85

13.078 21.34 37.895 157.64 143.834 116.03 102.94

14.429 23.456 140.23 111.488

19.4 24.1 26.4 153.2 156.8 132.1

19.4 21.2 192.8 163.4 171.2 137.2

20.6 27.7 149.1 149.7 117.3 117.3

19.8 24.5 122.7 155.3 147.2 128.9


Date

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

Ist 10-Daily Avg.

2nd 10-Daily Avg.

3rd 10-Daily Avg.

Monthly Average

161133-40ER-0007-00 Page 5 of 8



Anneuxre 5-2


16.0 13.5

14.9 13.3

14.8 13.4

14.8 13.0

13.7 13.2

14.6 13.6

14.6 13.5

13.6 13.0

13.4 13.5

12.1 13.1

12.3 13.4

12.2 13.4

12.1 13.8

12.1 14.4

12.0 13.9

12.9 13.7

11.9 14.1

13.9 16.3

12.3 16.7

11.5 14.3

12.1 14.4

11.8 13.9

11.8 14.3

13.8 14.6

12.8 14.1

11.1 16.3

11.9 14.0

14.5 13.9

11.7 13.9

11.9 16.3

14.6

14.3 13.3

12.3 14.4

12.3 14.6

13.0 14.1

Discharge Data of Par Barrage Site -Year 2011

Date

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

Ist 10-Daily Avg.

2nd 10-Daily Avg.

3rd 10-Daily Avg.

Monthly Average

161133-40ER-0007-00 Page 6 of 8



Anneuxre 5-2


14.2 11.8 7.7 15.2 29.7 27.8 75.1 48.3 43.2 78.3 15.4 12.3

14.2 11.8 7.4 16.0 30.1 25.7 60.9 49.9 42.0 65.1 14.8 11.1

14.4 11.7 7.2 16.8 29.9 42.1 76.8 51.8 38.2 113.3 14.3 12.2

15.6 11.7 7.1 16.6 29.7 23.7 60.4 45.8 37.1 94.2 14.6 10.5

16.2 12.4 7.0 16.7 29.8 25.1 83.5 53.7 30.9 77.6 14.0 11.8

15.7 11.9 7.0 17.3 29.9 40.8 97.4 54.2 27.0 61.0 14.1 13.6

15.6 11.7 7.2 17.2 29.7 30.3 44.9 41.6 27.8 64.8 14.0 13.3

14.1 13.3 7.2 16.9 30.1 23.5 46.4 42.3 26.5 45.6 13.8 10.4

13.8 12.5 7.0 17.3 29.9 21.9 53.8 39.6 27.2 45.0 13.4 13.0

13.7 11.6 7.5 17.4 29.7 15.9 43.4 41.8 26.4 41.6 12.1 10.1

13.2 11.7 7.3 17.1 29.8 21.3 64.2 36.6 27.3 42.8 12.8 11.8

13.0 11.4 7.1 16.9 29.9 29.5 74.3 27.6 24.4 42.7 12.7 15.4

13.5 11.0 7.0 16.9 30.1 46.4 125.8 27.1 33.7 45.9 12.6 13.7

13.1 10.7 7.2 16.9 30.1 54.7 137.9 19.3 137.9 41.8 12.8 14.8

13.0 10.4 7.1 16.9 30.2 113.1 107.8 24.9 109.2 40.8 11.8 11.8

13.8 10.3 7.2 17.1 30.2 62.3 81.9 24.0 130.4 39.5 12.1 12.0

14.2 10.3 7.2 16.9 30.2 43.4 75.0 22.9 130.4 40.6 11.9 13.9

13.4 10.3 7.2 17.1 30.4 22.5 60.0 25.4 219.3 38.9 11.6 19.2

13.2 10.1 7.0 16.9 31.1 28.5 57.6 20.5 217.4 38.1 12.1 19.4

13.2 10.3 7.0 16.7 32.2 26.4 64.9 19.6 224.1 36.9 11.2 14.1

13.8 10.1 7.1 16.7 33.2 38.3 51.9 31.5 222.1 30.1 12.6 18.8

14.2 10.1 7.1 16.5 34.4 49.9 44.8 45.8 220.8 30.4 11.7 13.6

13.7 10.2 7.0 16.5 35.9 34.2 62.3 36.2 243.3 28.9 11.6 17.8

14.3 10.5 7.1 16.1 34.4 61.2 74.3 48.1 245.8 28.2 13.9 16.5

12.8 9.9 7.0 16.2 34.6 130.6 74.6 66.2 224.9 19.2 12.3 13.7

12.8 9.3 7.1 16.0 32.8 222.8 62.2 42.3 225.7 18.5 12.0 19.2

12.4 8.8 8.4 16.3 30.9 269.2 46.5 39.7 142.6 18.3 11.3 13.8

13.7 8.4 9.7 16.5 31.5 198.1 67.3 39.3 132.0 17.9 13.9 13.5

13.0 7.9 12.3 16.6 32.0 84.7 64.9 37.2 118.8 17.5 11.6 13.4

12.8 12.9 16.7 29.6 76.0 51.9 33.4 87.1 16.5 12.0 18.5

13.0 14.7 27.5 47.4 41.2 15.0 14.6

14.8 12.1 7.2 16.8 29.9 27.7 64.3 46.9 32.6 68.6 14.0 11.8

13.4 10.7 7.1 17.0 30.4 44.8 84.9 24.8 125.4 40.8 12.1 14.6

13.3 9.5 9.1 16.4 32.4 116.5 58.9 41.9 186.3 21.9 12.3 15.8

13.8 10.7 7.8 16.7 30.9 63.0 69.4 37.9 114.8 43.8 12.8 14.1


Date

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

Ist 10-Daily Avg.

2nd 10-Daily Avg.

3rd 10-Daily Avg.

Monthly Average

161133-40ER-0007-00 Page 7 of 8



Anneuxre 5-2


15.4 12.3 14.2 17.3 22.0 34.6 93.5 31.9 39.3 28.1

15.5 12.4 13.3 15.9 18.2 36.3 71.5 25.9 65.5 27.1

18.7 11.6 14.3 17.2 20.1 34.5 34.7 22.1 67.8 25.4

14.3 12.1 14.3 16.4 23.9 26.0 28.6 22.3 65.0 34.5

17.6 14.0 13.3 16.8 26.7 25.8 53.4 22.3 104.7 25.7

17.3 11.9 13.3 13.5 25.1 27.1 81.0 30.1 157.5 60.3

17.6 11.9 14.3 14.3 25.2 23.1 68.9 37.6 89.7 50.9

14.5 11.3 14.3 13.9 24.1 23.5 46.5 43.2 87.5 27.4

14.2 11.0 13.0 13.9 24.3 24.5 47.4 56.7 64.7 25.8

14.0 12.0 16.5 13.1 22.5 23.0 65.2 49.2 65.5 29.4

12.0 11.9 15.2 13.7 23.4 19.3 53.4 44.8 56.3 27.2

11.7 10.8 15.8 17.8 30.4 18.9 41.8 33.2 58.1 25.6

13.1 9.7 16.1 22.7 35.4 23.0 41.6 40.0 53.9 25.4

12.4 11.5 14.3 18.3 42.1 16.1 41.0 34.4 56.0 24.7

12.0 9.9 14.3 21.5 36.0 14.8 38.1 29.1 48.2 26.1

14.9 10.6 15.1 20.2 42.0 13.1 34.8 28.4 29.4 22.2

15.4 11.2 14.8 17.1 36.3 12.0 29.5 33.3 28.6 22.5

12.4 11.0 14.7 14.5 37.5 20.0 42.9 31.9 25.0 34.9

12.7 9.8 13.6 18.0 45.4 26.3 38.2 29.4 28.8 22.5

11.8 10.5 13.0 24.1 30.9 39.8 43.4 29.7 29.4 25.1

14.1 9.7 14.3 17.0 26.9 31.2 72.5 29.5 28.0 26.4

14.4 9.9 14.3 15.8 29.0 21.0 60.9 26.1 26.2 25.1

13.1 10.8 17.7 15.6 37.2 27.0 37.0 24.5 30.5 23.4

14.5 11.0 17.9 16.6 44.0 24.3 45.9 22.1 23.0 25.4

11.8 8.4 13.3 17.2 47.1 24.5 34.4 42.1 21.8 25.0

12.2 9.7 13.3 14.7 31.5 29.2 37.0 75.6 21.3 25.8

10.5 10.3 12.6 16.8 26.7 43.3 39.0 54.8 21.0 24.0

14.2 10.8 12.6 17.8 25.2 48.1 60.9 57.3 25.5 28.6

12.2 14.7 18.5 34.3 58.7 38.5 35.0 28.1 29.2

11.9 17.8 21.1 45.0 67.6 33.4 50.6 26.4 28.6

11.9 15.1 44.3 29.0 29.6 0.0 26.1

15.9 12.0 14.1 15.2 23.2 27.8 59.1 34.1 80.7 33.4

12.8 10.7 14.7 18.8 35.9 20.3 40.5 33.4 41.4 25.6

12.8 10.1 14.9 17.1 35.6 37.5 44.4 40.7 22.9 26.2

13.8 10.9 14.5 17.0 31.6 28.5 48.0 36.1 48.3 28.4


Date

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

30

19

20

21

22

23

24

31

Ist 10-Daily Avg.

2nd 10-Daily Avg.

3rd 10-Daily Avg.

Monthly Average

25

26

27

28

29

161133-40ER-0007-00 Page 8 of 8



161133-40ER-0007-00

Annexure 5-3 Letter of Design Storm Value for Par, Turu and Dardu HEP

Annexure 5-3

Page 1 of 2

Annexure 5-3

Page 2 of 2

Temporal Distribution of 1-day Design Storm

18

31

41

47

52

5761

6468

7175

7880

8385

8789

9193

9496

97

0

10099

0

10

20

30

40

50

60

70

80

90

100

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24Duration (hrs)

% D

istr

ibut

ion



161133-40ER-0007-00

Annexure 5-4 Convolution of Unit

Hydrograph with Rainfall



Annexure 5-4Daily Rainfall = 350.6 mm

Baseflow (Rainfed) = 21.00 cumec

Total Baseflow = 21 cumec

Time (hr)UH

Ordinate (m3/s)

0.00 0.00 0.01 0.01 0.10 0.10 0.44 0.65 0.99 0.17 0.01 0.00 0.57 0.57 0.65 0.65 0.97 0.97 2.18 2.91 4.12 1.21 0.65 0.57DSRO

(m3/sec)

Design Flood

(m3/sec)

0 0 0.00 0.00 211 32 0.00 0.00 0.00 212 65 0.00 0.00 0.00 0.00 213 118 0.00 0.00 0.34 0.00 0.34 214 230 0.00 0.00 0.70 0.34 0.00 1.04 225 202 0.00 0.00 1.27 0.70 3.26 0.00 5.23 266 152 0.00 0.00 2.48 1.27 6.63 3.26 0.00 13.64 357 115 0.00 0.00 2.18 2.48 12.03 6.63 14.21 0.00 37.52 598 84 0.00 0.00 1.64 2.18 23.45 12.03 28.85 20.77 0.00 88.92 1109 59 0.00 0.00 1.24 1.64 20.60 23.45 52.38 42.19 31.71 0.00 173.21 194

10 42 0.00 0.00 0.90 1.24 15.50 20.60 102.10 76.59 64.42 5.45 0.00 286.80 30811 29 0.00 0.00 0.64 0.90 11.73 15.50 89.67 149.29 116.94 11.07 0.34 0.00 396.09 41712 17 0.00 0.00 0.45 0.64 8.56 11.73 67.48 131.12 227.94 20.10 0.70 0.00 0.00 468.71 49013 10 0.00 0.00 0.31 0.45 6.02 8.56 51.05 98.66 200.19 39.18 1.27 0.00 18.18 0.00 423.89 44514 6 0.00 0.00 0.18 0.31 4.28 6.02 37.29 74.65 150.64 34.41 2.48 0.00 36.94 18.18 0.00 365.38 38615 4 0.00 0.00 0.11 0.18 2.96 4.28 26.19 54.52 113.97 25.89 2.18 0.00 67.06 36.94 20.77 0.00 355.05 37616 2 0.00 0.00 0.06 0.11 1.73 2.96 18.64 38.30 83.25 19.59 1.64 0.00 130.70 67.06 42.19 20.77 0.00 427.00 44817 0 0.00 0.00 0.04 0.06 1.02 1.73 12.87 27.26 58.47 14.31 1.24 0.00 114.79 130.70 76.59 42.19 31.12 0.00 512.41 53318 0.00 0.02 0.04 0.61 1.02 7.55 18.82 41.62 10.05 0.90 0.00 86.38 114.79 149.29 76.59 63.21 31.12 0.00 602.02 62319 0.00 0.02 0.41 0.61 4.44 11.03 28.74 7.15 0.64 0.00 65.35 86.38 131.12 149.29 114.74 63.21 69.91 0.00 733.04 75420 0.00 0.20 0.41 2.66 6.49 16.85 4.94 0.45 0.00 47.73 65.35 98.66 131.12 223.65 114.74 142.01 93.19 0.00 948.47 96921 0.00 0.20 1.78 3.89 9.91 2.90 0.31 0.00 33.53 47.73 74.65 98.66 196.42 223.65 257.81 189.30 131.99 0.00 1272.73 129422 0.00 0.89 2.60 5.95 1.70 0.18 0.00 23.87 33.53 54.52 74.65 147.80 196.42 502.50 343.64 268.10 38.88 0.00 1695.24 171623 0.00 1.30 3.96 1.02 0.11 0.00 16.48 23.87 38.30 54.52 111.83 147.80 441.33 669.82 486.71 78.97 20.77 0.00 2096.78 211824 0.00 1.98 0.68 0.06 0.00 9.66 16.48 27.26 38.30 81.68 111.83 332.09 588.27 948.67 143.36 42.19 18.18 2360.70 238225 0.00 0.34 0.04 0.00 5.68 9.66 18.82 27.26 57.37 81.68 251.25 442.66 833.18 279.42 76.59 36.94 2120.91 214226 0.00 0.02 0.00 3.41 5.68 11.03 18.82 40.84 57.37 183.52 334.91 626.95 245.41 149.29 67.06 1744.31 176527 0.00 0.00 2.27 3.41 6.49 11.03 28.20 40.84 128.90 244.63 474.33 184.66 131.12 130.70 1386.59 140828 0.00 1.14 2.27 3.89 6.49 16.53 28.20 91.76 171.82 346.47 139.71 98.66 114.79 1021.74 104329 0.00 1.14 2.60 3.89 9.72 16.53 63.36 122.31 243.35 102.05 74.65 86.38 725.98 74730 0.00 1.30 2.60 5.83 9.72 37.14 84.45 173.23 71.68 54.52 65.35 505.84 52731 0.00 1.30 3.89 5.83 21.85 49.51 119.61 51.02 38.30 47.73 339.05 36032 0.00 1.94 3.89 13.11 29.12 70.12 35.23 27.26 33.53 214.21 23533 0.00 1.94 8.74 17.47 41.25 20.65 18.82 23.87 132.75 15434 0.00 4.37 11.65 24.75 12.15 11.03 16.48 80.43 10135 0.00 5.82 16.50 7.29 6.49 9.66 45.76 6736 0.00 8.25 4.86 3.89 5.68 22.69 4437 0.00 2.43 2.60 3.41 8.44 2938 0.00 1.30 2.27 3.57 2539 0.00 1.14 1.14 2240 0.00 0.00 2141 0.00 21

CONVOLUTION OF UNIT HYDROGRAPH FOR 50-Year Return Period

EFFECTIVE RAINFALL (cm)- II BELL EFFECTIVE RAINFALL (cm)- I BELL

161133-40ER-0007-00 Page 1 of 3






Time (hr)UH

Ordinate (m3/s)

0.02 0.02 0.05 0.05 0.15 0.15 0.54 0.78 1.17 0.23 0.05 0.02 0.68 0.68 0.78 0.78 1.15 1.15 2.53 3.36 4.75 1.42 0.78 0.68DSRO

(m3/sec)

Design Flood

(m3/sec)

0 0 0.00 0.00 211 32 0.66 0.00 0.66 222 65 1.34 0.66 0.00 1.99 233 118 2.42 1.34 1.49 0.00 5.25 264 230 4.72 2.42 3.03 1.49 0.00 11.67 335 202 4.15 4.72 5.50 3.03 4.83 0.00 22.23 436 152 3.12 4.15 10.72 5.50 9.80 4.83 0.00 38.11 597 115 2.36 3.12 9.41 10.72 17.80 9.80 17.33 0.00 70.54 928 84 1.73 2.36 7.08 9.41 34.69 17.80 35.21 24.84 0.00 133.10 1549 59 1.21 1.73 5.36 7.08 30.46 34.69 63.91 50.45 37.34 0.00 232.23 253

10 42 0.86 1.21 3.91 5.36 22.92 30.46 124.57 91.58 75.85 7.33 0.00 364.06 38511 29 0.60 0.86 2.75 3.91 17.34 22.92 109.41 178.50 137.70 14.88 1.49 0.00 490.37 51112 17 0.35 0.60 1.96 2.75 12.67 17.34 82.33 156.77 268.39 27.02 3.03 0.66 0.00 573.86 59513 10 0.21 0.35 1.35 1.96 8.90 12.67 62.29 117.97 235.72 52.66 5.50 1.34 21.88 0.00 522.78 54414 6 0.12 0.21 0.79 1.35 6.33 8.90 45.50 89.25 177.37 46.25 10.72 2.42 44.44 21.88 0.00 455.54 47715 4 0.08 0.12 0.47 0.79 4.37 6.33 31.96 65.19 134.20 34.80 9.41 4.72 80.68 44.44 24.84 0.00 442.41 46316 2 0.04 0.08 0.28 0.47 2.56 4.37 22.75 45.79 98.02 26.33 7.08 4.15 157.26 80.68 50.45 24.84 0.00 525.15 54617 0 0.00 0.04 0.19 0.28 1.51 2.56 15.71 32.60 68.85 19.23 5.36 3.12 138.11 157.26 91.58 50.45 36.66 0.00 623.50 64518 0.00 0.09 0.19 0.90 1.51 9.21 22.51 49.01 13.51 3.91 2.36 103.93 138.11 178.50 91.58 74.46 36.66 0.00 726.45 74719 0.00 0.09 0.60 0.90 5.42 13.19 33.84 9.62 2.75 1.73 78.63 103.93 156.77 178.50 135.18 74.46 81.00 0.00 876.62 89820 0.00 0.30 0.60 3.25 7.76 19.84 6.64 1.96 1.21 57.43 78.63 117.97 156.77 263.49 135.18 164.53 107.60 0.00 1123.17 114421 0.00 0.30 2.17 4.66 11.67 3.89 1.35 0.86 40.34 57.43 89.25 117.97 231.41 263.49 298.68 218.57 151.94 0.00 1493.98 151522 0.00 1.08 3.10 7.00 2.29 0.79 0.60 28.72 40.34 65.19 89.25 174.13 231.41 582.18 396.78 308.63 45.53 0.00 1977.03 199823 0.00 1.55 4.67 1.37 0.47 0.35 19.83 28.72 45.79 65.19 131.74 174.13 511.30 773.39 560.28 92.48 24.84 0.00 2436.10 245724 0.00 2.33 0.92 0.28 0.21 11.62 19.83 32.60 45.79 96.23 131.74 384.74 679.24 1092.08 167.88 50.45 21.88 2737.81 275925 0.00 0.46 0.19 0.12 6.84 11.62 22.51 32.60 67.59 96.23 291.09 511.11 959.13 327.23 91.58 44.44 2462.73 248426 0.00 0.09 0.08 4.10 6.84 13.19 22.51 48.12 67.59 212.62 386.69 721.72 287.39 178.50 80.68 2030.13 205127 0.00 0.04 2.73 4.10 7.76 13.19 33.22 48.12 149.34 282.46 546.04 216.25 156.77 157.26 1617.29 163828 0.00 1.37 2.73 4.66 7.76 19.48 33.22 106.31 198.39 398.85 163.61 117.97 138.11 1192.46 121329 0.00 1.37 3.10 4.66 11.46 19.48 73.40 141.23 280.14 119.51 89.25 103.93 847.52 86930 0.00 1.55 3.10 6.87 11.46 43.03 97.51 199.42 83.94 65.19 78.63 590.72 61231 0.00 1.55 4.58 6.87 25.31 57.16 137.70 59.75 45.79 57.43 396.16 41732 0.00 2.29 4.58 15.19 33.63 80.72 41.26 32.60 40.34 250.60 27233 0.00 2.29 10.12 20.18 47.48 24.19 22.51 28.72 155.48 17634 0.00 5.06 13.45 28.49 14.23 13.19 19.83 94.25 11535 0.00 6.73 18.99 8.54 7.76 11.62 53.64 7536 0.00 9.50 5.69 4.66 6.84 26.68 4837 0.00 2.85 3.10 4.10 10.05 3138 0.00 1.55 2.73 4.29 2539 0.00 1.37 1.37 2240 0.00 0.00 2141 0.00 21

CONVOLUTION OF UNIT HYDROGRAPH FOR 100-Year Return Period


161133-40ER-0007-00 Page 2 of 3






Time (hr)UH

Ordinate (m3/s)

0.05 0.05 0.08 0.08 0.19 0.19 0.62 0.88 1.31 0.28 0.08 0.05 0.78 0.78 0.88 0.88 1.28 1.28 2.81 3.72 5.25 1.59 0.88 0.78DSRO

(m3/sec)

Design Flood

(m3/sec)

0 0 0.00 0.00 211 32 1.49 0.00 1.49 222 65 3.02 1.49 0.00 4.51 263 118 5.49 3.02 2.41 0.00 10.92 324 230 10.70 5.49 4.89 2.41 0.00 23.48 445 202 9.40 10.70 8.87 4.89 6.07 0.00 39.92 616 152 7.07 9.40 17.29 8.87 12.34 6.07 0.00 61.03 827 115 5.35 7.07 15.18 17.29 22.39 12.34 19.83 0.00 99.45 1208 84 3.91 5.35 11.43 15.18 43.65 22.39 40.27 28.08 0.00 170.26 1919 59 2.74 3.91 8.64 11.43 38.33 43.65 73.11 57.03 41.83 0.00 280.67 302

10 42 1.95 2.74 6.31 8.64 28.85 38.33 142.50 103.54 84.97 8.82 0.00 426.66 44811 29 1.35 1.95 4.43 6.31 21.82 28.85 125.15 201.81 154.25 17.92 2.41 0.00 566.25 58712 17 0.79 1.35 3.16 4.43 15.94 21.82 94.17 177.24 300.65 32.54 4.89 1.49 0.00 658.47 67913 10 0.47 0.79 2.18 3.16 11.20 15.94 71.25 133.37 264.05 63.42 8.87 3.02 24.83 0.00 602.54 62414 6 0.28 0.47 1.28 2.18 7.97 11.20 52.04 100.90 198.69 55.70 17.29 5.49 50.43 24.83 0.00 528.74 55015 4 0.19 0.28 0.75 1.28 5.50 7.97 36.55 73.70 150.33 41.91 15.18 10.70 91.55 50.43 28.08 0.00 514.40 53516 2 0.09 0.19 0.45 0.75 3.23 5.50 26.02 51.77 109.80 31.71 11.43 9.40 178.44 91.55 57.03 28.08 0.00 605.43 62617 0 0.00 0.09 0.30 0.45 1.90 3.23 17.97 36.85 77.12 23.16 8.64 7.07 156.72 178.44 103.54 57.03 41.08 0.00 713.60 73518 0.00 0.15 0.30 1.14 1.90 10.53 25.45 54.90 16.27 6.31 5.35 117.93 156.72 201.81 103.54 83.44 41.08 0.00 826.81 84819 0.00 0.15 0.76 1.14 6.20 14.92 37.91 11.58 4.43 3.91 89.22 117.93 177.24 201.81 151.48 83.44 89.84 0.00 991.95 101320 0.00 0.38 0.76 3.72 8.77 22.22 8.00 3.16 2.74 65.17 89.22 133.37 177.24 295.26 151.48 182.49 119.10 0.00 1263.08 128421 0.00 0.38 2.48 5.26 13.07 4.69 2.18 1.95 45.77 65.17 100.90 133.37 259.32 295.26 331.29 241.91 167.86 0.00 1670.86 169222 0.00 1.24 3.51 7.84 2.76 1.28 1.35 32.59 45.77 73.70 100.90 195.13 259.32 645.73 439.17 340.96 50.83 0.00 2202.07 222323 0.00 1.75 5.23 1.65 0.75 0.79 22.50 32.59 51.77 73.70 147.63 195.13 567.12 856.00 618.97 103.25 28.08 0.00 2706.91 272824 0.00 2.61 1.10 0.45 0.47 13.19 22.50 36.85 51.77 107.84 147.63 426.74 751.79 1206.47 187.44 57.03 24.83 3038.71 306025 0.00 0.55 0.30 0.28 7.76 13.19 25.45 36.85 75.74 107.84 322.86 565.71 1059.59 365.36 103.54 50.43 2735.43 275626 0.00 0.15 0.19 4.66 7.76 14.92 25.45 53.92 75.74 235.83 428.00 797.32 320.88 201.81 91.55 2258.15 227927 0.00 0.09 3.10 4.66 8.77 14.92 37.23 53.92 165.64 312.63 603.23 241.45 177.24 178.44 1801.32 182228 0.00 1.55 3.10 5.26 8.77 21.82 37.23 117.92 219.58 440.62 182.68 133.37 156.72 1328.63 135029 0.00 1.55 3.51 5.26 12.84 21.82 81.42 156.31 309.48 133.43 100.90 117.93 944.47 96530 0.00 1.75 3.51 7.70 12.84 47.73 107.93 220.31 93.72 73.70 89.22 658.42 67931 0.00 1.75 5.14 7.70 28.08 63.27 152.12 66.72 51.77 65.17 441.71 46332 0.00 2.57 5.14 16.85 37.22 89.17 46.07 36.85 45.77 279.63 30133 0.00 2.57 11.23 22.33 52.46 27.00 25.45 32.59 173.62 19534 0.00 5.62 14.89 31.47 15.89 14.92 22.50 105.28 12635 0.00 7.44 20.98 9.53 8.77 13.19 59.92 8136 0.00 10.49 6.35 5.26 7.76 29.87 5137 0.00 3.18 3.51 4.66 11.34 3238 0.00 1.75 3.10 4.86 2639 0.00 1.55 1.55 2340 0.00 0.00 2141 0.00 21

CONVOLUTION OF UNIT HYDROGRAPH FOR SPF


161133-40ER-0007-00 Page 3 of 3



161133-40ER-0007-00

PLATES

Plate 5-1

MAP

Plate 5-2

Documents

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