96 MW SIPPI H.E. PROJECT

Ringong ARUNACHAL PRADESH

Preliminary Feasibility Report

February 2015

TABLE OF CONTENTS

CHAPTER DETAILS PAGE NO.

CHAPTER I Executive Summary 3

CHAPTER II Background Information 11

CHAPTER III Project Area 16

CHAPTER IV Topographic & Geo-technical Aspects 18

CHAPTER V Hydrology 23

CHAPTER VI Conceptual Layout and Planning 30

CHAPTER VII Power Potential Studies 38

CHAPTER VIII Power Evacuation 41

CHAPTER IX Environmental Aspects 43

CHAPTER X Infrastructure 57

CHAPTER XI Construction Planning & Schedule 65

CHAPTER XII Economic Evaluation 70

CHAPTER – I

EXECUTIVE SUMMARY

CHAPTER I

EXECUTIVE SUMMARY 1.1 INTRODUCTION

Sippi Hydroelectric Project located in Upper Siang District of Arunachal

Pradesh envisages a run of the river scheme with utilization of water of river

Ringong for power generation and harnessing a head of about 150.0 M.

The project with a proposed installation of 96MW (3X32 MW) would afford

an annual energy generation of 414.09 GWH in a 90% dependable year.

The tariff from the project would be Rs. 3.84 per unit (levelised).

The diversion weir site is located at latitude 29°0’50.23’’ N & longitude

94°48’23.84’’E. The barrage site is approachable from Along-Migging-Tuting

road at a distance of about 291 Km from Along and 289 Km from Yingkiong,

Distt, Head quarter of Upper Siang District. The nearest rail head is located at

Nagoan (Assam) and nearest airport is at Leelabari North Lakhimpur (Assam). 1.2 SCOPE OF WORKS

SIPPI HE Project envisages construction of:

• One no. 6.5 m diameter, 600 m long Diversion Tunnels with u/s coffer

dam

• 20m height Un-Gated Weir

• Intake Structure with one gate

• 3 nos. 100 m long De-silting basins of 8 m width and 12 m height.

• One no. 6.5 m diameter D shaped concrete lined 1.5 km long Head Race tunnel.

• One no. 15m diameter & approx. 30 m high Surge Shaft.

• Three no. steel lined circular Pressure Shafts of 3.0 m diameter 200 m

long each.

• Surface Power House of size 70m x22 m x 3 5 m consisting of 3

Vertical Francis units of 32MW each.

• Tailrace channel of about 500 m length 1.3 HYDROLOGY

The river Ringong drains a catchment area of about 732 Sq Km at the

proposed barrage site based on using the Google earth images. At present

there is no Gauge Discharge data on Ringong Asi and in the absence of the

Gauge discharge data in the catchment, water availability of pre feasibility

study, for the proposed project has been computed by considering flow

series of Yamne-I HEP on ca t ch me n t a r e a p r op o r t io n b as i s .

Accordingly the Design discharge is considered as 73.5 Cumecs and

the installed capacity for this project has been worked out to 96 MW. The

Annual energy generation in 90% dependable year has been worked out to

414.09 GWH considering 100% machine availability.

The design flood for the 1:100 year frequency has been assumed as 5cumecs

per square kilometer of the catchment which works out to 3660 Cumecs.

1.5 POWER EVACUATION ASPECTS

The power generated from all the projects coming in the region like Sippi

HEP, Pango HEP, Jidu HEP and Palsi HEP would be first pooled at

Mosing Switchyard and then evacuated through 400 KV double circuit line

either at Passighat or at Along for further evacuation to Northern Grid

through HVDC link of PGCIL.

1.6 ENVIRONMENTAL ASPECTS

The project is located in Ringong river catchment in Upper Siang district,

Arunachal Pradesh. The total land requirement for the construction of the

project would be about 40 Ha. Based on assessment of environmental

impacts, management plans have to be formulated for catchment area

treatment, compensatory afforestation and other environmental issues.

These issues would be taken care of during preparation of DPR. 1.7 ESTIMATE OF THE PROJECT COST

The project is estimated to cost Rs. 786.89 Cr. including IDC and

transmission cost. The preliminary cost estimate of the project has been

prepared as per guidelines of CEA/CWC. The breakup of the

cost estimate is given below:

Civil Work

Electro Mechanical Works

Sub total (Generation)

Transmission Works

Total (Hard Cost)

IDC

Grand Total 1.8 FINANCIAL ASPECTS

Rs. 435 Crores

Rs. 180 Crores

Rs. 615 Crores

Rs. 25 Crores

Rs. 640 Crores

Rs. 146.89 Crores

Rs. 786.89 Crores

As indicated above, Sippi HE Project with an estimated cost of Rs. 786.89

Crores (including IDC of Rs. 146.89 Crores) and energy generation of

414.09 GWH in 90% dependable year is proposed to be completed in a

period of 5 years. The tariff has been worked out considering a debit equity

ratio 70:30, 16% rate of return on equity, annual interest rate on loan at 11%

and 10% of energy as Free Power to home state available after losses. The

tariff has worked out to Rs. 3.84.

1.9 CONCLUSIONS

Sippi HE Project involves civil works and can be completed in 5 years out of

which 1.5 years required for infrastructure works. The project would afford

energy of 414.09 GWH in a 90% dependable year. The cost per MW

installed works out to be Rs. 8.19 Crores.

SALIENT FEATURES OF SIPPI HE PROJECT

1. Location

State Arunachal Pradesh District Upper Siang River Ringong Location of Barrage site Latitude 29°0’50.23”N Longitude 94°48’23.84”E Location of Power House Latitude 29°0’30.06”N Longitude 94°49’8.28”E Nearest big rail head Nagoan (Assam) Nearest Airport Leelabari (North Lakhimpur)

2. Hydrology

Catchment area 732 km2 Design flood in 100 yrs 3660 cumecs

3. Diversion Tunnel

Diameter & shape 1no 6.5m dia D-shaped Length 600m Diversion discharge 120 cumecs (Non-monsoon) Diversion tunnel one gate (6.5m x 6.5m)

4. Coffer Dam

Type Rock fill with central clay core Max. height of u/s coffer dam 10.0m Max. height of d/s coffer dam 5.0m

5. Weir

Type Concrete Gravity, Un-gated Weir Weir Crest and Pond Level El + 880.00m River bed level at barrage site El + 860.00m Weir height ( river bed level –

Crest level of weir) 20m

Length of barrage 120 m Scour sluice:

Nos. of size of opening (wxh) 4nos of 4.5 x 4.0 m each

Maximum Flood Discharge 3660 Cumecs Maximum Flood lift over crest 6 m U/s Maximum Flood Level EL + 886.00 m T B L EL + 890.0 m

6. Intake

Numbers One

Invert level El 863M Size of gate 6.0m x 6.0m Design discharge 73.5 cumecs plus 14.7 cumecs provision

for silt exclusion. Total 88.20 cumecs 7. De-silting arrangement

Nos. type and size of de-silting basins

3nos. Dufour type each 100m long, 8m wide and 12m height

Total design discharge in each chamber

30.0 cumecs (including 20% flushing)

Particle size to be removed ≥0.2mm 8. Head Race Tunnel

Numbers One Size & type 6.0m, D shaped, concrete lined. Design discharge 88.2 cumecs

Length 1.5 km Adits 1nos. 4.5m D-shaped

9. Surge shaft

Size & type 15m diameter, Restricted orifice Vertical shaft height 30m

10. Pnstock

Numbers 3 Type Steel lined Diameter 3.0m Penstock length 200m

11. Power House complex

Type Surface Minimum tail water level at outlet 730.0m Turbine axis elevation 730.0m Type of turbine Vertical Francis Generating Units 3 x 32 MW Gross head 150m Rated net head 145m Power house size 70 m x 22 m x 35m

12. TRC

Numbers One Size & type Open channel, concrete lined Length 500m

13. Switch Yard

Type, size Surface, 100 m x 100 m Power generation Installed capacity 96MW (3x32MW) + 20% COL

Energy generation in 90% dependable year

414.09 GWH

14. Cost Estimates & Financial aspects (Rs. In Crores)

Civil works Rs.435 Crores Electro Mechanical works Rs.180 Crores Subtotal (Generation) Rs.615 Crores* Transmission Works Rs.25 Crores Total (Hard Cost) Rs.640 Crores IDC Rs.146.89 Crores Grand total Rs.786.89 Crores

*Total cost is exclusive of R&R/Land cost

CHAPTER – II

BACKGROUND INFORMATION

Conceptual planning of the project

After carrying out site visits and based on the geology of various sites, topography of

area etc., the following has been firmed up in the preparation of this PFR.

i. Location of Weir: At EL +860 M. river bed level with Crest Level of 880.0 M

ii. Location of Powerhouse: At EL +730 M.( Normal TWL)

The locations of Weir and power house are preliminary in nature and shall be subject to review at the stage of detailed investigations.

> A preliminary conceptual layout & planning of the project has been attempted

by the project based on the availability of topo-sheets and Google Maps

incorporating weir and Power House locations, HRT alignment and

TRC outfall, diversion etc.

> Preliminary design feature:

Weir:

The project is envisaged to have a 20 meter high Un-Gated weir from river bed

of about EL ± 860 M. The site has been selected as the valley is narrow and the river

bed is geologically sound rock. The length of weir required to dispose the

maximum flood discharge of 3660 cumecs is 120 M. The crest level/Pond

level is fixed at ± 880 M. The maximum flood level at the weir is EL + 886 M,

Considering a free board of 4 M, the T B L is fixed at EL + 890 m.

Intake Structure: The Intake Structure is located on the on the right flank of the river.

The sill level of the Intake is kept at EL + 863 m. The size of the Intake Gate is 6m X

6m.

Head Race Tunnel:

The water from the I n t a k e s t r u c t u r e w i l l be discharged i n t o 6 . 0 M

dia. D- shape Head race tunnel. The Head race Tunnel is proposed to run

underground along the right side hill fo r a l ength o f 1 .5 Km. Since the HRT

alignment is falling in Young Himalayan geological area, providing of steel ribs at

different location may be needed.

Geological surprises are envisaged to be encountered during the execution of

Head race tunnel. The HRT has been considered for water conductor system due to

the following reasons:

i) Large overburden in the area, as open channel shall require large

excavation.

ii) The stretch from weir site to Power House encounters slide zones making it

difficult to construct open channel.

iii) As the rainy season in this region prolongs from May to October, over ground

construction may be hampered and may require long duration and may not be

cost effective.

Power House:

A surface Power house has been proposed based on the field study and topo-sheets/

Google Maps. The location of the power house has been fixed keeping in view the

proposed TWL of EL ± 730 M.

Tail Race Arrangement:

An open channel (concrete lined) of 500M length is proposed for discharging the

water from the power generating units directly back into the original river Ringong

Asi.

River Diversion

An underground tunnel for a stretch of 600 M length is proposed to divert the river

flow during the construction of weir and appurtenant works with provision of

upstream and downstream non- overtopping cofferdam 2.1 GENERAL

Sippi Hydroelectric Project is located in Upper Siang District of Arunachal Pradesh

near tehsil headquarter of Tuting which is connected by a single lane all weather road

maintained by BRO. Tuting is around 289 km from Yingkiong, district

headquarter of Upper Siang District and 291 km from Along, district headquarter of

West Siang Distt.

2.2 POWER SCENARIO OF ARUNACHAL PRADESH

The state of Arunachal Pradesh is bestowed with enormous potential for power

generation of the order of around 27,000 MW, out of which about 500 MW has been

developed so far which is 1.8 % of the total available potential. The peak power

requirement of this state is 95 MW. Arunachal Pradesh have highest number of high

head mini and micro hydro projects in India. The state has about 37 nos. of power

plants ranging from 5 KW to 4500 KW. By 2015 the power requirement of state has

been estimated as 400 MW.

The project locations viz., Weir and Power House sites are approachable. At present

there is no motorable road up to the project components. The Project site is

approachable only by foot that too with very much difficulty in thick and steep

forest. The area falls under dense forests of tropical monsoon forest having its

entire catchments area within the Indian Territory. At present, there is a micro hydro

project existing near Tuting town with an installed capacity of 100 KW which is

located on a rivulet named Sikut. This micro hydro caters to the needs of the local

populace in and around Tuting. 2.3 RINGONG BASIN

The river Ringong is perennial one and originates in the upper reaches of Indian

Territory bordering China in the north. The river is fed by Himalayan glacier,

small rivulets, streams and monsoon rainfall. River Ringong is a tributary of main

river Siang. The catchments area of the river up to the proposed site is 732 sq. km.

The scheme falls under the Siang river basin. The W e i r site is situated at longitude

94048’23.84” E and latitude 2900’50.23” N. The river bed level at proposed w e i r

site is around EL 860 m.

The location of Power House is 29000’30.06”N & 94049’8.28”N The observed

discharge of river Ringong during the first week of Jan’ 2010 (i.e. Lean season) was to

the tune of 3 0 -35 Cumecs just upstream of the confluence of this river and Siang.

However, from the Google images, the catchment is computed and design discharges

are obtained based on the approved flow series of Yamne-I HEP by considering

catchment area proportion.

The river has a steep gradient of the order of 1:30. From the local enquiry, it

transpired that there is considerable discharge during the summer and rainy season. 2.4 NECESSITY OF SIPPI HE PROJECT

The power scenario of the country is becoming precarious day by day with the ever

increasing demand of the energy during the last one decade and fast economic growth.

However, the projected economic growth of the country has not grown as anticipated

during the last one decade due to power shortage in the country in all the spheres. India

has been facing electricity shortages in spite of appreciable growth in electricity

generation. The demand for electrical energy has been growing at the faster rate and

shall increase at higher growth rate to match with the projected growth of Indian

economy.

In view of the acute shortage of the power availability in the country and in the state of

Arunachal Pradesh in particular and as a matter of fact, the economic development of

this state and north east on the whole has been lagging far behind when compared to

the other regions of the country, it is necessary to develop hydropower potential of

Arunachal Pradesh. No major industries could come up since independence due to non-

availability of energy despite the region being rich in hydropower development. Thus it

has become essential to develop maximum power potential of Arunachal Pradesh. It

will help in development of Arunachal Pradesh and North East part of India.

CHAPTER – III

PROJECT AREA

CHAPTER III

PROJECT AREA

3.1 GENERAL The Project location falls in remotest areas of the state of Arunachal Pradesh. The

main occupation of the local population is agriculture. The main agriculture produce

of the area is paddy. Besides, millet, pineapples, oranges, etc., are also grown but in

very less quantity.

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

economic development of the entire area will be booming. The project shall bring

socio-economic development of not only to the project area but also to the other areas

which are located downstream of Tuting (nearest tehsil or headquarter). Improved

road communication, better education and civic amenities are bound to follow

which will act as a catalyst for development of the entire area in all spheres. The project is located on river Ringong which is a tributary of river Siang. The river

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

nature. A run off the river scheme is proposed. There is no population either in the

nearby area or in its entire catchment area of said project. Moreover, there is no

water requirement for riparian rights and discharge of river being small, it does not

require flood mitigation in the downstream of the project location. Thus no storage

scheme is required.

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

Himalayan g l ac i e r s and s ma l l s t r eams . Besides, the entire catchments

receives moderate to heavy monsoon showers from May to October each

year. The approximate discharge measured during the first week of Jan 2010 has

been observed to be 30-35 Cumecs i.e., during the lean season. From local enquiry

it was learnt that there is appreciable hike in the level of water level during the

rainy season i.e. April to October.

CHAPTER – IV

TOPOGRAPHIC & GEO-TECHNICAL ASPECTS

CHAPTER IV

TOPOGRAPHICAL AND GEOTECHNICAL ASPECTS

4.1 DRAINAGE AND CLIMATE

The project area falls in Upper Siang District of Arunachal Pradesh, , where altitude

varies from 500m to about 4500m. At places, the valley is characterized by very

high hi l ls on ei ther s ide of the r iver . The hills, particularly to the south of

valley, show N-S to NNE-SSW trends Mountain slopes are dissected by seasonal and

perennial drainages, cliffs and snowcapped peaks are also present in the area. The

geomorphic features of the region are results of orogeny and denudation processes.

The tributaries show dendritic to sub-parallel pattern in the upper reaches and

parallel pattern in lower reaches.

The higher reaches of the area commonly experience a few meter thick snowfall

during winter and temperature drops down to -50C to -100C. 4.2 PHISIOGRAPHY

The Arunachal Pradesh could be divided into four distinct physiographic domains

namely Himalayan ranges, Mishmi hills, Naga Patkai ranges and Brahmaputra plains,

each having a different geology and tectonic set up. The Himalayan ranges, where the

project is located are the eastern most part of the Great Himalayan ranges and they

occur as a gigantic crescent with convex side towards south and extend from Western

border of Bhutan to Dibang and Lohit valleys in the east, abutting against Mishmi

hills. Further, the Himalayan ranges could be divided in to four parallel linear zones,

namely Tethys or Tibetan Himalaya, Higher Himalaya, Lesser or lower Himalaya and

Sub Himalaya Lesser or Lower Himalayan hill ranges, which host the project, are

located between the Greater or Higher Himalaya in north and Sub Himalaya in south

with elevation ranging from 2500 to 4500 M and width of about 80-90 Km.

The zone comprises of Late Palaeo-Proterozoic unfossiliferous sediments in the Siang Valley.

4.3 REGIONAL GEOLOGY

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

sharp bend in the Siang district, where it swings from NE-SW in the west to NW-SE

in the east, across the Siang Gorge, defining the so-called Eastern Syntaxial Bend

(ESB). This bend is built up of Proterozoic to Cenozoic rocks, most of which occur in

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

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

WSW and NW-SE trends in the west and east respectively. The structural architecture

of the ESB comprises of three major thrust sheets namely Siang, Siyom and Rikor in

descending tectonic order and a complex Para autochthonous zone discernible in the

central part wherein the Abor Volcanic, the Yingkiong Formation and the Dalbuing

Formation are exposed.

Regionally the whole area is an association of different litho–tectonic unit and was

mapped by Surendra Singh and et.al (GSI) in 1962-83 field seasons on 1:50,000

scale. Based on distinct litho-tectonic association, they classified these rocks as

follows: Table-4.1: Litho-Tectonic Succession of Siyom Valley Area West Siang District,

Arunachal Pradesh

Formation Litho-units

Tuting Granite and Gneiss Biotite-granite, streaky gneiss, augen

Gneiss

………………………………Tuting thrust………………………….…………

Monigong Formation Schistose quartzite, biotite-schists,

marble, amphibolite bands.

Piddi Formation Massive to schistose quartzite with biotite- schists bands

Pari Mountain Formation Gneisses and Migmatites

Siyom Formation Massive to schistose quartzite with thin

bands of biotite-schists, phyllites and

slates, black slates with limestone bands,

metavolcanics and chlorite-schists.

………………………………Luyor Thrust………………………….……………

Ragidake Formation Grey to straw yellow sandstone, siltstone,

black shale and thin gritt bands

………………………………Unconformity……………………………………

Nikte Formation Coarse grained ortho-quartzite, feldspathic sandstone and purple shale intercalation: diamictite bands and black slates

The project area is covered by rocks of Nikte and Siyom Formation. These are

unfossiliferous in nature and have undergone repeated deformational events. The

rocks have dominantly N-S to NNE-SSW trend. In northern parts, the rocks of

Siyom Formation truncated by Tuting thrust while in the south the rocks extend up to

lower Subansiri district. Towards eastern part of the project area, Tuting-Basar Fault

lineament is present along which rock formation of Siyom valley abuts against that of

Siang valley. This fault separates distinct geological formations of Siang and Siyom

valley. Tectonically, Siyom Formation overrides Nikte Formation along the Luyor

thrust. Again S.Singh and et.al, in 1993, subdivided Siyom Formation into Rumgong

member and slate-limestone rich Gasheng member.

4.3.1 LINEAMENT

State Remote Sensing Application Center, Itanagar, have traced two sets of

lineaments, one trending N-S and another NE-SW within the area on the basis of

satellite imagery interpretation. 4.4 GEOLOGY AROUND PROJECT STRUCTURES

4.4.1 It is seen that the tunnel would pass mainly through different kind of gniesses/

quartzites /dolmites. The project components would be finalised at appropriate

locations once complete team of geologist and engineers complete their study and then

layout of the scheme will be developed. However, as there is good exposed rock all

along the project area, there appears to be no difficulty in planning and executing the

project.

There are no residential use of the land in and around the project components. 4.5 CONSTRUCTION MATERIALS

In the vicinity of the project, there are no major river terrace/shoal deposits, visible on

either bank of the Ringong River. For construction of the proposed diversion

structure and other allied structures, the requirement of coarse and fine aggregate

can be met from the limestone / dolomitic limestone, quartzite deposits on right bank

on the upstream of weir axis.

The requirement of coarse and fine aggregate for power tunnel as well as powerhouse

can be met from quarries / crushing facilities developed at weir site.

CHAPTER – V

HYDROLOGY

CHAPTER V

HYDROLOGY 5.0 GENERAL

Sippi H.E project is a run of the river scheme, proposed on Ringong Asi River, a

tributary of river Siang, in the upper Siang district of Arunachal Pradesh. The project

envisages construction of a 20 m high diversion structure, about 10 km upstream of

the confluence of Siang with river Ringong Asi.

Detailed hydrological investigations and analysis could not be carried out due to

Non availability of the Gauge d ischarge data immediately. The catchment area of

the river at the weir site has been worked out on the basis of the Google images

and the design discharge is computed on the basis of area proportion method by

considering already approved flow series of Yamne-I HEP and the flood discharge

has been assumed on the basis of 5 cumecs per square km catchment. During the

preparation of DPR, the hydrological data from the nearby stations wil l be

collected and gauge station installed at the weir s i te and also at power house site. 5.1 RIVER SYSTEM AND BASIN CHARACTERISTICS

The river Ringong Asi is a perennial river and originates in the upper reaches of

Indian territory, boarding China in the north. The main source of flow in the river is

snowmelt from Himalayan glaciers and small streams. Ringong Asi is a mountainous

river with steep river bed slope and having an appreciable discharge with considerable

catchment area.

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

river known as the Tsangpo in Tibet, the Siang or Dihang in Arunachal Pradesh and the

Jamuna in Bangladesh, is one of the biggest rivers in the world. The 2,906 km long

Brahmaputra, bigger than Ganga in length and volume, traverses its first 1,625 km in Tibet,

the next 918 km in India and the remaining 363km in Bangladesh upto Bay of Bengal. It

originates from an altitude of 5300m about 63 km south east of the

Manas Sarovar lake in southwest Tibet is the mighty river is known as Tsangpo. The source

of the river lies in the Kanglung Kang glacier 82° – 10’ (E) and 30° – 30’ (N) near Konggyu

lake (4877 m) and the Kailash range of Himalayas. Many tributaries join the infant

river from the pass of Mayumla (5150 m) and Marnyak-La (5303 m). These passes separate

the Brahmaputra Basin from Manas Sarovar lakedistrict in which two other great Indian

rivers, the Indus and the Sutlej have their source. Many other glaciers contribute snow melt

all along the river into its upper reaches. The river in its eastward journey through the

southern Tibet traverses about 1700 km keeping a course roughly parallel to and about 160

km away from the main Himalayas. After traversing 1625 km in Tibet, Tsangpo emerges from foothills of eastern

Himalayas in Indian territory of Arunachal Pradesh. Before entering India, the river flows in

a series of big cascades as it rounds the Namcha Barwa massif. Tsangpo is known as Siang

after crossing the Indo-Tibetan border. The part of Siang basin in India is bounded on the

north by eastern Himalayas, on west by Subansiri basin and on east by Dibang basin. Also

the Siang basin consists of sub basins of its tributaries Siyom, Yangsang Chu, Simong,

Ringong, Simong, Yame Siku and Sibia besides its own. The lower reaches of eastern

Himalayas abruptly rise from the plains and from the Indo-China border where the catchment

is snowfed. The north bank tributaries have very steep slopes and shallow braided channels

for a considerable distance from the foothills and in some cases right up to the outfall. The

south bank tributaries have comparatively flatter gradient and deep meandering channels

almost from foothills.

The project area has a rugged terrain and river Ringong Asi has a steep gradient. The river

bed slope near the weir site is about 1:30 and the average river bed elevation at the proposed

weir site is about EL 860 m. The area is covered with thick vegetation.

5.1.1 CATCHMENT AREA AND WATER AVAILABILITY

The catchment of the river is having elongated shape. Several small streams are

joining the main river on both left and right sides. As the slope of the river is very

steep, the velocity in the river is high, but due to presence of rock strata and rock

boulders in the river bed, the high velocity of flow is dissipated. The entire catchment is

having thick vegetation and there are no habitants in the catchment area. The catchment

area up to proposed weir site is about 7 32 Sq.km. Due to non-availability of all the

1:50000 SOI topo-sheets, the catchment plan have been derived from Google earth

images.

The water availability at the proposed location is worked out based on the already

approved series of Yamne-I on catchment area proportion basis and the flow series for

25 years has been arrived. The water availability in 90% dependable year is also

calculated and flow duration curve for the water availabity in 90% dependable year has

been drawn. The design discharge is considered as 73.5 at 90% dependability, which is

the required discharge for the proposed power development of 96 MW.

The details of flow series etc., are appended to the report in the end.

The Maximum flood discharge is generally worked out to 5 cumecs per 1 Sq Km of

catchment area. Hence, the maximum flood discharge at the weir location is

considered as 3660 cumecs. 5.1.2 TEMPERATURE AND HUMIDITY

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

mainly responsible for abrupt changes in the climatic conditions and aided by the

complex orography, the area experiences frequent rainfall of varying intensity and

duration. The maximum temperature recorded at Tuting (nearest Tehsil or

headquarter) is 320C and minimum 60C, the maximum and minimum temperature at

Pugging / Yinkiong is 360C and 70C, at Dibrugarh 30.90C and 10.20C, at Tezpur

32.20C and 11.40C respectively. The relative humidity at these stations varies from

maximum of 94% to minimum of 60%. The basin experiences extreme cold

temperatures during winter months. Temperature and relative humidity observations

are being made at Tuting since Aug 2001. 5.1.3 PRECIPITATION CHARACTERISTICS

The climate of project area may be described as tropical monsoon climate. The

southwest monsoon normally enters Assam and adjoining areas around the end of

May, establishes firmly over the entire northeast India by the end of June.

It withdraws from this region in the second week of October. During the four

monsoon months of June to September, different low-pressure systems like

depressions, cyclonic storms, etc. originate in the Bay of Bengal. When they cross the

Indian coast sometimes move in an easterly to north -easterly direction causing heavy

rainfall over the basin. The project area and its vicinity observe its first remarkable

shower during 1st or 2nd week of April.

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

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

33.8 cm, (Pant et al.1970) is comparable in magnitude to the rainfall of any of the

monsoon months.

The heavy rainfall in the catchment is usually associated with the following

synoptic situations:

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

north from its normal position and lies close to the foothills of the Himalayas.

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

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

India.

5.1.3.1 RAIN GAUGE NETWORK

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

primarily for flood control work. Gradually more rain-gauge stations have been

installed in the Siang Basin by different agencies.

Although the rain gauge network in Brahmaputra basin has not reached the

international standard, efforts have been made continuously to improve and a fairly

useful network of meteorological stations has been established. But no rain gauge

station exists in the catchment of Sippi H.E project. However, there are five rain

gauge stations in the adjoining area of the project namely Tuting, Migging, Gelling,

Mayum and Nyering. Difficult terrain with lack of round the year access facilities is

the main constraint for establishing the rain gauge stations as per network design

requirements. The data from these stations shall be collected later on.

5.2 Stream flow and River gauges

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

first Gauge-Discharge station was established at Passighat on Siang river in 1949 and

measurements are taken regularly up to 1962. Discharge observations for period of

12 years from 1963 to 1974 were discontinued at Passighat. About 2 km upstream of

Passighat one more gauge-discharge site was established at Ranaghat and daily

Gauge-Discharge measurement were started from January 1978. On Siyom river,

Brahmaputra Board established a G&D site at Pangin which is situated near the

confluence of river Siyom with Siang river, about 72 km downstream of the proposed

Middle Siang barrage site. In the upper catchment, Brahmaputra Board established

G&D sites at Tuting and Yinkiong. NHPC had its G&D sites at Rotung, Pangin,

near Middle Siang barrage site and Goging in the Siang catchment for the period

between 2000 to 2004.

For pre-feasibility stage study, a design flood of 3660 cumec is recommended at

proposed barrage site. On availability of more data/information, design flood

need be estimated by deterministic approach using unit hydrograph technique and

probabilistic approach using flood frequency analysis during preparation of DPR.

5.3 SEDIMENTATION

4 numbers of Scour Sluices of size 4.5 m X 4 m are proposed to flush out silt

from time to time. The sill levels of the Scour sluices are kept at the river

bed level to release water as per downstream requirements. De-silting

chambers are also provided for excluding silt before the diverted water is entered

into the Head race Tunnel.

5.4 RECOMMENDATIONS FOR FUTURE STUDIES

The following are the improvements suggested for feasibility/DPR stage study:

• Proper rain gauge network along with Gauge-discharge-

sediment observation sites on the river near the proposed weir

axis need be established before taking up preparation of DPR.

• After establishing gauge and discharge site on the river with

proper rain gauge network in the basin, detailed water

availability study need be conducted in /DPR stage.

• On availability of more data/information, design flood

need be estimated by deterministic approach using unit

hydrograph technique and probabilistic approach using flood

frequency analysis in DPR

stage.

CHAPTER – VI

CONCEPTUAL LAYOUT & PLANNING

CHAPTER VI

CONCEPTUAL LAYOUT AND PLANNING 6.0 INTRODUCTION

The Sippi H.E. project is located in Upper Siang district of Arunachal Pradesh

upstream of the proposed Upper Siang H.E. Project. It is a run of the river

scheme with some storage proposed to harness hydel potential of the river

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

150 m between weir site and Power House is proposed to be utilized for

power generation. The powerhouse will have an installed capacity of 96 MW. 6.1 PROJECT COMPONENTS

SIPPI HE Project envisages construction of:

• One no. 6.5 m diameter, 600 m long Diversion Tunnels with u/s coffer

dam

• 20 m high Un-Gated Weir

• Intake Structure with one gate.

• Three nos. 100 m long De-silting basins of 8 m width and 12 m height.

• One no. 6.0 m diameter D shaped concrete lined 1.5 km long Head Race

Tunnel .

• One no. 15m diameter & approx. 30 m high Surge Shafts.

• Three no. steel lined circular Pressure Shafts of 3.0 m diameter of 200

m long each.

• Surface Power House of size 70m x22 m x 3 5 m consisting of 3

V e r t i c a l F r a n c i s units of 32 MW each.

• Tailrace channel of about 500 m length.

6.2 Weir / River diversion works The w e i r s i t e has been located at about 10 km. up stream of the

confluence of Ringong river with Siang river. Width of the valley at weir site varies

from 60 m at river bed level to 120 m at EL 880 m. Average bed level at weir site

is EL 860 m. The crest level/ Pond level of the weir is proposed to be fixed at EL

880 m. The both banks of river Ringong at the weir site are steeper and show

dark grey to black coloured, strong and massive to banded slate limestone of

Siyom formation.

The weir is proposed to be designed for d i spos ing a 1 in 100 year flood of

3660 cumecs.. Total length of the over flow structure is 1 2 0 m. The head of water

over the crest is worked out to 6 m. The downstream face of the weir is fitted with

ogee shape curve to improve the efficiency of the flood discharge. 4 Nos of Sluice

vents are proposed for silt exclusion with size of 4.5 m X 4.0 m. These shices will be

utilized for release of water as per downstream requirements. One no. Concrete lined

6.5 m diameter D shaped , 600 m long diversion tunnel has been proposed on the

left bank of the river to divert a flood of approx.120 cumecs. In order to divert the

river water during construction of the weir, an u/s cofferdam of approx. height 10m

and d/s cofferdam of 5 m height is proposed. 6.3 Power Intakes and De-silting arrangement

The proposed power intake system proposed on the right bank, which is a

rectangular section on the right bank of the river of size 6m X 6M which leads

in to three de-silting chambers . The diverted water is further leads into 6.0 m

dia and 1.5 Km long D-Shape Tunnel (HRT). The si l l level of the intake

structure has been kept at EL 863 m taking into consideration the water seal

requirement to prevent the vortex formation and air entrainment.

As this level being 3 m higher than the r i v e r b e d l e v e l , it w i l l ensure

reduced entry of sediments in the water conductor system. The intake structure

shall be provided with the trash racks to prevent the entry of trash in the water

conductor system.

As the project is being conceived as entirely a run off the river scheme, for the

efficient, trouble free and continuous operation of turbines with least possible wearing

and erosion due to silt, a provision of de-silting arrangement has been made. Three

nos. Dufour type 100 m long de-silting basins of 8 m width and 12 m height has

been provided to remove the 0.2 mm and bigger particles at 90% efficiency. The de-

silting basins have been provided with central gutter with holes to facilitate the

flushing of settled silt particles through the flushing tunnel. 6.4 Head Race Tunnels, Surge Shafts, and Pressure Shafts

The proposed one no.6.0 m diameter D shaped concrete lined head race tunnels of 1.5

km length, are designed to carry a design discharge of 73.5 cumecs. The diameter has

been fixed keeping the velocity of water below 3.0 m/s in the tunnel at the same time

the size should be good enough for movement of machinery for excavation and

concreting. The rock cover above head race tunnel generally varies from +60 m to

+300 m. The low cover reaches, if any, will be confined to prominent nalla

crossings and sufficient protection works will be taken up in this reach. The HRT

shall intersect strong to very strong massive to banded limestone/dolomitic

limestone. The tunnel is proposed to be lined with 300 mm thick plain M-25

concrete. The rock support shall consist of grouted rock bolts/anchors and shotcrete

with or without wire mesh as per geological conditions encountered. If soft strata is

encountered, a fool proof supporting system with steel rib supports, lagging slabs etc.,

will be provided.

One no. simple type surge shaft of about 3 0 m height has been proposed. The

finished diameter of Surge Shaft according to Thoma’s Criteria comes to about 15m.

Surge shaft is proposed to be concrete lined with 1 . 0 m thick R.C.C lining.

Three nos. of circular Steel penstocks confirming ASTM standard of 3.0 m

diameter are drawn from the Surgeshaft to f e e d w a t e r t o 3 units of vertical

Francis turbines each of 32 MW. The length of each Penstock is about 200 m. The

required discharge from each penstock is 24.5 cumecs, which corresponds to a

velocity of 3.47 m/sec.

6.5 Power House Complex & Tail Race Channel

The surface Power House is located on the right bank of Ringong river upstream of

proposed Upper Siang H.E. Project. The rock type to be encountered in the power

house area is slaty limestone/dolomitic limestone with bands of quartzite. It will have

an installed capacity of 96 MW (3 generating units of 32 MW each). The units are

spaced at a distance of 2 3 m center to center. The center line of the turbine is

proposed at about EL 730 m. The deepest level of the draft tube pit is at EL 720

m. One number electrically operated overhead traveling crane (E.O.T) of apprx. 120

MT capacity shall be provided for handling of the equipment. The Main inlet valve

is proposed inside the powerhouse structure itself. The dimension of the main

Power House structure will be length 70m, width 22 m and height 35 m. A

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

bay structure proposed just u/s of power house structure of approx. size is 70 m x 14

m .

Cables from transformers will be taken to the Switch yard by cable trench. A cable

trench structure of size 2.0 m X 2.0 m will take off from transformer area and shall

carry cables to the Switch yard. The Switch yard shall measure about 100 m x 100

m, which shall be formed in cutting / filling. Water from the turbines is discharged

back to Ringong river through three nos. draft tubes which deliver into tailrace

Channel. This TRC will be 500 m long with its bed level at start as +725M.The

tailrace outlet level of 730 M has been kept keeping in view the FRL of proposed

Upper Siang H.E. project . 6.6 Further Studies

6.6.1 Topographical Studies

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

firm up the various components of the project.

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

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

6.6.2 Geological and Geo-technical investigations

Geological / geotechnical investigations shall be required to be conducted including

surface mapping and subsurface explorations like exploratory drilling / drifting and

geophysical profiling at the barrage Rock mechanic lab tests shall be required for

finding out the properties of the rock material. Construction material survey shall be

required to be undertaken involving drifts, pits, and topographical surveys of the

borrow/quarry areas. Site specific studies for earthquake design parameters shall also

be required to be undertaken. 6.7 Design Studies

Hydraulic design of various structures like Weir, intake structure, transient studies of

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

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

parameters. Hydraulic model studies for reservoir, D i v e r s i o n w e i r and

Desilting arrangement shall be required for the confirmation of design parameters.

6.8 HYDRO-MECHANICAL EQUIPMENT

General Following hydro-mechanical equipments have been envisaged for Sippi HE Project:

6.8.1 Diversion Tunnel Gates and Hoists:

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

number diversion tunnel of 6.5 m diameter. One Gate of size 6.5 m X 6.5 m is

proposed to control the flood releases to downstream of the river.

6.8.2 S lu ice G at s Gates:

The Scour sluices are proposed to provide 4 Nos of Sluice gates of size 4.5 M X 4.0 M

(one set Main Gate and another set for stop log) will be provided to regulate the flow in

to the river and also to flush the silt whenever required. Each gate shall be operated by

rope drum hoisting arrangement. The Scour sluice barrel is fi t ted with steel

l iner to protect from the rolling stones coming along the river flow. 6.8.3 Power Tunnel Intake Gate with Hoist, Trash Rack and Raking Machine: A fixed

wheel type gate for opening size 6 m x 6 m shall be provided just downstream of the

intake bell mouth. The sill of the gate is located at EL 863 m. The gate shall be

operated by means of dedicated electrically operated rope drum hoists of 20 T

capacity located on the hoist platform installed over steel trestles. On upstream of

the Intake an inclined trash rack (15° with vertical), shall be provided. The cleaning of

the trash rack shall be done by means of a trash-raking machine.

6.8.4 De-silting Basin gates:

To isolate the de-silting basin for maintenance and inspection one bulkhead gate

for opening size 6.0 m X 6.0 m has been proposed at the entrance of Head race

Tunnel. H o i s t a r r a n g e m e n t w i l l b e p r o v i d e d t o r e g u l a t e f l o w a s

p e r r e q u i r e m e n t . 6.8.5 Flushing tunnel gates, Hydraulic hoists:

Two set of flushing tunnel sliding type gates, one set for each flushing tunnel,

comprising of one service gate (d/s) and one emergency gate (u/s) having a clear

opening of 2.0 m (wide) x 2.0m (high) have been proposed. Bonnets and bonnet

covers for both the gate grooves and hoist supporting structures for both the gates are

required to be provided. Each gate shall be operated by means of an independent hoist. 6.8.6 Surge Shaft Gate

3 Nos of Surge shaft gates are provided at the inlet of penstock separately to regulate

the flow leading to Turbine units. Hoist arrangement to the Gates is made for

operation as per requirement.

6.8.7 Draft Tube Gate:

The draft tube emerging out from each generating bay is provided with one gate

each for opening size of 4 .0 m X 4.0 m to isolate the generating units from tail

water. The gate will have an upstream sealing (pressure / tailrace side) and upstream

skin plate. Each gate shall be operated by means of dedicated rope drum hoist of 20 T

capacity.

6.8.8 Miscellaneous:

a) Diesel Generating Set & Hydraulic Fluid Filtering Unit

A three-phase synchronous type diesel generating set of 500 KVA, 450 Volts, 50 Hz

is envisaged for the emergency operations of the HM equipments at the barrage site.

The diesel generating set shall be located in the barrage area and to provide back-up

supply to gate operating equipments and to the computerized control system in case of

power failure.

Provision shall be made for one no. filter unit to purify the hydraulic oil along with

one unit contamination checking kit for checking of contamination level & one no. of

low vacuum de-hydration and de-gasification unit to remove water and gases from

Hydraulic oil.

CHAPTER – VII

POWER POTENTIAL STUDIES

CHAPTER - VII

POWER POTENTIAL STUDIES 7.0 INTRODUCTION

The installed capacity has been worked out on the basis of the design discharge provided as 73.5 cumecs and considering a Gross head of 150 m and net head of 145 m

The salient features of the project are as follows: -

Installed capacity

No. & size of unit

Type of power house

Net head

Design discharge per unit

Type of Switchyard

Turbine type

Speed of turbine

Generation voltage

Transmission voltage

GSU Transformer Energy

generation in 90%

dependable year with 95%

Machine availability

= 96 MW with 20% COL

= 3units of 32 MW

= Surface

= 145 meters

= 24.5 Cumecs

=220/ 400 KV GIS

= Vertical Francis

= 500 rpm

= 11.0 KV

= 220/400 KV

= 3 Nos. , Three-phase = 462 MU

7.1 Available Data

The Power Potential studies have been carried out based on following data:

a) Design Discharge considered as 73.5 cumecs

b) FRL& TWL Levels are 880M and 730 M respectively. Gross head is 150 M and Net Head is 145 M after deduction for hydraulic losses.

7.2 Fixation of FRL Level

The Crest level of the weir is proposed at EL + 880.0 M, which is the

pond level. The height of the weir above the average river bed level is 20

M. As it is a run of the river Scheme, the storage capacity of the reservoir is not

significant. 7.3 Fixation of Tail water level (TWL)

The tail water level of Sippi power house is Kept as EL +730 M All these values shall require to be reviewed during detail investigation of the

Scheme ie., weir site, power house complex and Tail race vis a vis

Topographical and geological features of the area. 7.4 Operating Head and Head Losses

Head losses in the water conductor system have been taken as 5 M . 7.5 Annual Design Energy

The net 10 daily average discharges in 90% dependable year are arrived by deducting

the mandatory environmental releases from the corresponding Gross flows.

Considering a net head of 145 m and machine efficiency of 92%, the power developed

and energy generated for the 96 MW installed capacity is calculated. The annual

energy generated during the 90% dependable year 2004-05, with 100% machine

availability works out to be 414.09 GWH. The Annual Plant load factor is computed

as 49.23% 7.6 Installed Capacity

The installed capacity of the Power house has been proposed as 96 MW

Power developed = 9.81*73.5*145*0.92 =96 MW

Assessment of the Power development and energy generation with various

installed capacities are also done and finally the installed capacity is fixed at

96 MW. The detailed Power potential calculations and Graphs are append

to the report in the end.

CHAPTER – VIII

POWER EVACUATION

CHAPTER - VIII

POWER EVACUATION 8.0 INTRODUCTION

The Sippi H.E. Project is envisaged for the installation of three generating

units of 32 MW each, operating under a rated net head of 1 4 5 m in a

surface type power house. The generation voltage is proposed to be 11.0 KV.

This voltage will be stepped up to 220/400 KV voltage level through

Generator step-up transformers. The power from Sippi H.E. Project would be

fed to the pooling station at Passughat/ Along to be ultimately connected to

the National Grid through EHV/HVDC transmission lines. 8.1 EXISTING POWER EVACUATION FACILITIES

Power system is controlled by the Electricity boards/

Departments /Corporations of the states of Assam, Meghalaya, Arunachal

Pradesh, Nagaland, Manipur, Mizoram and Tripura.

Power System Networks of PSUs located in the region are two 400KV line

going to Balipara from Dikrong (Ranga Nadi) power station and two 132KV

line are also emanating from Dikrong Switchyard and feeding to Along and

Nirjuli areas. 8.2 PROPOSED EVACUATION ARRANGEMENT

It is proposed to provide two outgoing bays for evacuating power at 400 KV

level from Sippi H.E. Project. The power from all the Projects would be

pooled near any one project and shall be further fed into pooling station either

at Passighat or Along for ultimate connection to Northern or national grid..

CHAPTER – IX

ENVIRONMENT ASPECTS

CHAPTER-IX

ENVIRONMENTAL ASPECTS 9.1 INTRODUCTION:

The proposed Sippi HE Project envisages construction of a 20m high barrage on river

Ringong/Sirapateng in Arunachal Pradesh. The State lies between 26º28’ to 29º30’ N

latitude and 90º30’ to 97 º 30’ E longitudes. Mc-Mohan Line bounds the state in the

north from China and Burma (Myanmar) in the east, Assam & Nagaland in the south

and Bhutan in the west. Its terrain consists of lofty, haphazardly aligned ridges that

separate deep valleys and rise to the peaks of the Great Himalayas. The State’s main

river is the Brahmaputra known in Arunachal Pradesh as the Siang, and its tributaries

viz. the Tirap, the Lohit (Zayu Qu), the Subansiri, and the Bhareli. The project lies in

the seismic zone V. 9.1.1 Location

Sippi H.E project (96 MW) is a run of the river scheme, proposed on Ringong river, a

tributary of river Siang. The project envisages construction of a 20m (approx.) high

Un-Gated weir and a Power house to install 3 units of 32 MW Turbine – Generator

units. The project is proposed to be located in Upper Siang district of Arunachal

Pradesh near Tuting, which is about 279 km from Yingkiong. 9. 2 PHYSICAL ENVIRONMENT

9.2.1 Climate/Meteorology

The climate of project area may be described as tropical monsoon climate. The

southwest monsoon normally enters Assam and adjoining areas around the end of

May, establishes firmly over the entire northeast India by the end of June. It

withdraws from this region in the second week of October. During the monsoon

months (June to September), different low-pressure systems like depressions, cyclonic

storms, etc. which originate in the Bay of Bengal when they cross the Indian coast,

sometimes move in an easterly to north-easterly direction causing heavy rainfall over

the basin. It is to be mentioned here that there is considerable thunderstorm activity in

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

33.8 cm, (Pant et al.1970) is comparable in magnitude to the rainfall of any of the

monsoon months. The average annual rainfall at Tuting is observed as 370 cm.

The variation in altitude is mainly responsible for changes in the climatic conditions

in Siang Basin. The maximum temperature recorded at Tuting (nearest Tehsil) is 32°C

and minimum 6°0C, the maximum and minimum temperature at Pugging / Yinkiong

is 36°C and 7°C, at Dibrugarh 30.9°C and 10.2°C, at Tezpur 32.2°C and 11.4°C

respectively. The relative humidity at these stations varies from maximum of 94% to

minimum of 60%. The basin experiences temperature decrease rapidly with altitude. 9.2.2 Topography

The area is mountainous with deep narrow valleys. At Tuting and Yingkiong the

valleys are wider. The entire terrain extends over the gorgeous eastern Himalayan

panorama from the tip of the outer Himalayan Siwalik formation in the south to the

inaccessible inner Himalayas in the North known as the Abor Hills. The topography

of the area is rugged with deep gorges and high hills. The entire area being situated in

the Himalayas is covered with massive mountains with East-West alignment which

are cut up by numerous streams and rivers with the formation of valley in between

them. The slopes in the valley are very steep with thick vegetation. The altitude of the

terrain dealt with ranges from about 100 m in the south to about 3100 m in the North.

9.2.3 Soils

The general and average soil character of cultivable land in the district is mainly

alluvial and composed of a mixture of sand (course to fine) and clay in varying

proportions. Soils in the area are results of degradation and weathering of rocks as

well as depositional features in the form of river terraces. The soil on the slopes is

mainly composed of silt and support good vegetation. The rocks exposed in the area

are prone to weathering due to heavy rainfall.

The clayey soils formed on river terrace due to river deposits are fertile and has

been developed into paddy fields by the local inhabitants.

9.2.4 Geology

The project area is covered by rocks of Nikte formation comprising of coarse grained

ortho-quartzite, feldspathic sandstone & purple shale intercalation and Siyom

Formation comprising of massive to schistose quartzite with thin bands of biotite-

schists, phyllites & slates, black slates with limestone bands, metavolcanics &

chlorite-schists. These are unfossiliferous in nature and have undergone repeated

deformational events. The rocks have dominantly N-S to NNE-SSW trend. In

northern parts, the rocks of Siyom formation are truncated by Tuting thrust while in

the south the rocks extend up to lower Subansiri district. Towards eastern part of the

project area, Tuting-Basar Fault lineament is present along which rock formation of

Siyom valley lies against that of Siang valley. This fault separates distinct geological

formations of Siang and Siyom valley. Tectonically, Siyom Formation overrides

Nikte Formation along the Luyor thrust. 9.2.5 Seismicity

The entire north east region has been classified in zone-V of the seismic zoning map

of India. As such the project area lies in seismically active zone V of seismic zoning

map of India IS: 1893(Part I); 2002. The zone is broadly associated with a seismic

intensity of IX on modified Mercelli Scale (M.M. Scale). 9.2.6 Catchment Area

The project is located in the Ringong Asi basin, which is a part of the Siang basin

situated in the North Eastern part of India.

The catchment of the river is of elongated shape. The catchment area upto the

proposed weir site is about 732 Sq.km. 9.2.7 River System

The river Ringong Asi is a perennial river and originates in the upper reaches of

Indian territory, bordering China in the north. The main source of flow in the river

is snowmelt from Himalayan glaciers and small streams. Ringong Asi is a

mountainous river with steep river bed slope and having an appreciable discharge

with considerable catchment area. The river has its confluence from west with the

main river Siang. The Brahmaputra river known as the Tsangpo in Tibet, the Siang or

Dihang in Arunachal Pradesh and the Jamuna in Bangladesh, is one of the biggest

rivers in the world. The 2,906 km long Brahmaputra, bigger than Ganga in length and

volume, traverses its first 1,625 km in Tibet, the next 918 km in India and the

remaining 363km in Bangladesh upto Bay of Bengal. It originates from an altitude of

5300m about 63 km south east of the Manas Sarovar lake in southwest Tibet where

the mighty river is known as Tsangpo. The source of the river lies in the Kanglung

Kang glacier 82° – 10’ (E) and 30° – 30’ (N) near Konggyu lake (4877 m) and the

Kailash range of Himalayas. Many tributaries join the infant river from the pass of

Mayumla (5150 m) and Marnyak-La (5303 m). These passes separate the

Brahmaputra Basin from Manas Sarovar lake district in which two other great Indian

rivers, the Indus and the Sutlej have their source. Many other glaciers contribute snow

melt all along the river into its upper reaches. The river in its eastward journey

through the southern Tibet traverses about 1700 km keeping a course roughly parallel

to and about 160 km away from the main Himalayas. After traversing 1625 km in

Tibet, Tsangpo emerges from foothills of eastern Himalayas in Indian territory of

Arunachal Pradesh. Before entering India, the river flows in a series of big cascades

as it rounds the Namcha Barwa massif. Tsangpo is known as Siang after crossing the

Indo-Tibetan border. The part of Siang basin in India is bounded on the north by

eastern Himalayas, on west by Subansiri basin and on east by Dibang basin. The north

bank tributaries have very steep slopes and shallow braided channels for a

considerable distance from the foothills and in some cases right upto the outfall. The

south bank tributaries have comparatively flatter gradient and deep meandering

channels almost from foothills. The river bed slope near the barrage site is about 1:40

and the deepest river bed elevation at the proposed barrages site is about EL 640m. 9.2.8 Land Use Pattern

Total land requirement for the construction of various project components is about

40 ha. Most of the land falls under the category of Dense Forest land. The land use

pattern surrounding the proposed submergence area and the w e i r site has been

studied using satellite data. These studies have been conducted by NRSA, Hyderabad

by using IRS-1D LISS-III & PAN merged satellite data and using ERDAS Imagine

image analysis software.

9.2.9 Water Quality

The river Ringong flows through forest areas in its entire course. No Population is

residing along the reservoir length. Industry or other such establishments are absent.

The low cropping density coupled with negligible agro-chemical loading also means

that there is no pollution load due to agrochemicals. Hence in the absence of any

major anthropogenic and other industrial establishments in the area, it can be

concluded that there are no major source of water pollution in the area. Thus water

quality of the river is generally expected to be very good. However water quality

analysis (Physico-Chemical analysis) of river water would be conducted as a part of

the EIA & EMP Study. 9.3 BIOTIC ENVIRONMENT

9.3.1 Vegetation

In Arunachal Pradesh, forest constitutes about 82% of the total geographical area

(83,743 sq.km.). The favourable rainfall, temperature, high humidity, undulated

topography with lofty hill ridges and deep valley and soils have resulted in varied

ecological diversity which subsequently influenced in growth of a very rich and

fascinating vegetation in the North Eastern states. Among the seven northeastern

states, Arunachal Pradesh is the largest and it exhibits rich biodiversity. 9.3.2 Flora

The major Tropical forest types found in the project area are tropical evergreen and

tropical Semi evergreen. Tropical evergreen forests are also termed as south Bank

tropical Wet evergreen (Dipterocarpus) forest and North bank tropical evergreen

(Nahar Jutuli) forest. North Bank Tropical evergreen (Naharjutli) forest occurs along

Semi-evergreen forest belt up to an elevation of 900m. Although no single species is

dominant, however following associations are found: Mesua-Altingia, Altingia-

Engahardia, Altingia-Syzygium, Mesua-Syzygium.

Tropical Semi evergreen forest spreads all along the forest hills and river bank up to

an elevation of 1100m. Tropical semi evergreen forest can be sub divided into two

distinct sub type i.e. Low hills and plain semi evergreen forest and riverine semi

evergreen forest. The trees reported in these forests are Terminalia Myriocarpa,

Phoeba goalparensis, Michalia hampaca, Mesua ferrea, Artocarpus chaplasa,

Chukrasia tabularis, Amoora walichii, Ailanthus grandis, Chinnamomum

cecicodaphne, Schima Wallichii,Pterospermium acerifolium, Toona ciliate,

Mangifera Indiaca etc.

9.3.3 Fauna

Project area has fairly good forest cover and serves as a habitat for many faunal

species, Major faunal species reported in the area are discussed below: 9.3.3.1 Mammals

Major mammels species reported in the area are Tiger (Panthera tigris), Leopard (

Panthera Pardus), Leopard cat ( Felis bengalensis), Fishing cat ( Falis viversina),

Large Indian Civet (Viverra Zibetha), Small Indian Civet (Paguma Larvata),

Common Mangoose (Herpestes Edwards), Jackal (Canis aureaus), Samba (Cervus

unocolor), Himalayan Black Bear (Selenarctos Hibetanus), Marbled Polecat (

Boomela Peregusna), Indian Gerbille (Tatera Inidaca),sheep etc.

9.3.3.2 Snake

Snake species reported in the area are Python molurus bivittatus (Burmese Python),

Elephes radiate (Copper head), Ptyas Korras ( Indo Chinese rat snake), Rhabdophis

himalayansus ( Himalayan Keelback), Amphiesma stolata ( Striped keelback), etc.

9.3.3.3 Birds

Some of the Avifauna reported in the project area is as below:

1) The Great Indian Hornbill (Buceros bicorris)

2) Himalayan wood Owl ( Strix aluco)

3) Peacock Pheasant( Polyplectroh bicalcaratum)

4) Bered Pheasant ( Crossapitilon gallus)

5) Red jungle Fowl ( Gallus gallus)

6) Sparrow Howk ( Accipiter nisus)

7) Green Pigeon (Treron Phoenicontera)

8) Himalayan pied kingfisher (Ceryle luxurbris)

9) Jungle crow (Corvue mecrophynachae)

10) Small skylark (Alanda gulaula) etc. 9.3.3.4 Aquatic fauna

The fish species reported in the Ringong river are as under:

1) Tor putitora, 2) Tor tor

3) Tor khudree

4) Tor mussulah

5) Tor Mosal

6) Schizothorax richardsoni

7) Schizothorax plagiostomus

8) Schizothorax moleswarthi

9) Eal

10) Oxygaster bacaila 9.4 SOCIO-ECONOMIC ENVIRONMENT:

9.4.1 Population

The total area of Upper Sing District is 6188 sq.km. with its head quarter at

Yingkiong. The Population as per 2001 census (provisional) is 33146 out of which

males are 17844 and females are 15302, the density of population per sq.km. is 05

persons. The sex ratio is 858 females per 1000 males. The district has the literacy rate

of 48.86%.The population consists of indigenous schedule tribes, as under:

A) Adis comprising Pasi, Pabarrage, Karko, Panggi, Ashing, Simong, Tangam, Komkar, Milang.

B) Idu Mishmi C) Khamba

D) Membas

The main festivals of tribal people are

A) Solung, Etor & Aran of Adis B) Losar of Memba & Khamba

C) Reh of Idu Mishmi. 9.4.2 Literacy

The literacy rate of male and females are 58.64 and 39.09 respectively. 9.4.3 Agriculture

Agriculture is the main occupation of the people living in and around the project area,

Both Jhum and settled cultivation are practiced in the area. The climatic condition and

soil types are favorable for cultivation of Paddy. Maize, Millet and vegetable. The

following table shows the average yield per hectare. Total area under principal crops

as on 31.3.2001is as follows:

Type of Crops

1. Paddy Area in ha

1337

2. Maize 134 3. Millet 252.1

9.4.4

Horticulture

Production in MT

2540.3

361.8

226.8

The main horticultural products found in the area are Plum, Peach, Apple, Walnut,

Pears, Guava, Pineapple, Banana, Orange etc.

9.4.5 Education

To cater the educational needs of the people, the district administration has

constructed several schools in the region, which are as follows:

1. Higher Secondary school 03

2. Secondary School 02

3. Middle School. 10

4. Primary School 49

9.4.6 Medical and Public Health

The project area has inadequate medical facilities however following medical

facilities are available at district level:

1. District Hospital 01

2. Primary Health Center 04

3. Health Unit/ Dispensary 12

9.4.7 Existence of Any Protected Area in the Project Vicinity

EIA and EMP study will be under taken to study protected areas if any existing in the

Project vicinity.

9.5 PREDICTION OF ENVIRONMENTAL IMPACTS

The construction as well as operation activities of the project have certain

impacts on the ecosystem, if proper care is not taken during the construction

and operation phases of the project. Although, the impacts during the

construction phase are temporary and could last only till the construction

activities are under progress, the repercussion of

certain activities like construction, tunneling, quarrying and land

clearing for construction of project appurtenances etc. may cause

environmental degradation if the step towards restoration of the environment

is not taken well in time. The proposed project area falls under Dibang-

Dihang Biosphere Reserve and so it is essential that detailed study may be

taken to estimate the probable impacts of the project on the various

components of environment with special reference to the bio-diversity of the

Biosphere Reserve. Major impacts anticipated from the project

construction and operation may be summarized as under:

9.5.1 Impact on Land Environment

Total submergence area of the project is about 5 ha. As per the Land-use map

prepared by NRSA for Submergence area, 40% of the area is a part of the

river course . No Agriculture land and Human Settlements is observed in the

area. The land required for the project is primarily forest land. As the project

area falls within the Biosphere Reserve detailed impact assessment should

be done to assess the impacts likely to accrue on the biodiversity, so that the

suitable management plans may be delineated. The direct impact of

construction activity of a water resource project in a hilly terrain is generally

limited to the vicinity of the construction sites. Submergence of forest area is

practically nil and it has no population The acquisition of land for various

project activities would lead to cutting of vegetation on these lands. Most

of the environmental impacts due to construction work are temporary in

nature.

All these issues are to be properly addressed in the EIA/EMP of the project so

that the long term effects, if any, can be minimized. Landslides aspect will

also be studied in detail in EIA study and accordingly feasible remedial

measures shall be proposed for restoration of the landslide areas.

About 500 workers and 100 technical staff are anticipated to congregate

during the construction phase of the project. Solid waste / sewage generated

form the project colonies / labour camps may pollute the land if

proper measures for waste management are not adopted. All these issues

are to be properly addressed in the EIA/EMP of the project so that the long

term effects, if any, can be minimized. 9.5.2 Impact on Water Environment

The impact due to formation of reservoir on the migratory routes of the fishes

and the impact due to impoundment of water on other aquatic fauna may

be studied and necessary management plans/mitigation measures may be

framed up to address the problem. The important changes that are likely to

happen in this area are: reduction in flow rate, changes in water temperature,

reduction in population of stenothermal species (species adapted to small

temperature range) and increase in population of eurythermal species

(species adopted to higher temperature range). During the construction

phase there may be some instances of excavated and quarried material

getting washed away along with the rain water into the river that may cause

turbidity or sedimentation downstream. Natural sedimentation emanating

from severely degraded catchment area is one of the important issues to be

addressed. Also waste disposal and management (human excreta and

domestic sewage) due to congregation of large population of migrant

labourers will be encountered. Proper waste management measures are

required to be implemented during the construction phase of the project so

as to protect water body from pollution. The project would also envisage

construction of temporary and permanent residential areas to accommodate

labour and staff engaged. This would result in the production of domestic

waste, human excreta, which if discharged into the river directly could affect

the quality of river water. Proper waste management plan (Solid and liquid)

may therefore be framed in EMP report and implemented to mitigate adverse

effect of waste on aquatic environment. 9.5.3 Impacts on Air and Noise Environment:

Impacts on the air environment is limited to the construction phase of a

hydropower project. The major sources of air pollution during construction

phase are emission from crushers, DG sets, construction equipments etc.

Thus local air pollution (including dust and odor) will result from the

operation of plant machinery and traffic. Noise and vibration due to

construction activities (e.g. blasting, machinery and traffic) may disturb local

wildlife and human populations. However, there will be only short-term

increase in emissions like SO2 and Suspended Particulate Matters (SPM)

during the construction period of the project. The level of noise would also

decrease substantially once the construction phase is over. Hence no

major impact is anticipated on this account.

9.5.4 Impacts on flora and fauna

The direct impact of construction activity of a water resources project in a hilly

terrain is generally limited to the vicinity of the construction sites. This may

alter the local diversity of flora and also affect habitat available for fauna.

Changes to, or loss of habitat will affect areas used for mating, breeding,

nursing, moulting, feeding, and drinking for both resident and migratory

wildlife.

The extent and severity of these effects will vary according to the existing

habitat and the particular species involved which would be known after

detailed study of flora and fauna is done during the comprehensive

EIA/EMP study. The project area falls under Dihang-Dibang Biosphere

reserve however, detailed study with respect to anticipated impacts (if any)

on the biosphere reserve shall also be undertaken during EIA studies to access

the impact of the project especially during construction phase.

9.5.5 Impacts on Avifauna

The construction of the proposed weir will lead to formation of a reservoir,

which will have a fluctuation in the water level to some extent., which

precisely means h a b i t a t f o r t h e reservoir kinds of birds, especially

water birds.

However because of the presence of a good habitat it is quite likely that

water birds will flock in this area in a large number. The birds from cold

climatic areas could also use this area during the winter season.

9. 5.6 Impacts on Fishes

There are few migratory fish species reported in the Ringong river. A

barrage will fragment and isolate upstream resident fish. The resident species

may congregate in the tail water release site. Fish from upstream will

occasionally sweep downstream during the monsoon, stay in the tail water or

swim further downstream. The cons t ruct ion of weir may obstruct the

route of the long and mid-distance migratory fish. Hence fish passage has to be

provided in the Scour sluice portion. The impact of the weir on fish

particularly migratory fish species would be studied in detail during

comprehensive EIA study and based on it the suitable mitigation measures

would be suggested.

9.5.7 Impacts on Socio-Economic environment:

No villages and population is likely to be affected by acquisition of

land for construction of the project, however a detailed socio-economic

survey would be carried out as a part of the EIA/EMP study to ascertain

the degree and extent of impact on socio-economic environment of the

region and accordingly a suitable rehabilitation package would be

formulated for project affected families (if any). During the construction of

the project the basic problem relates to management of large population that

migrates to the area in search of jobs and other allied activities. Thus

migration of a population having different cultural, ethnic and social

backgrounds has its own advantages and disadvantages. Exchange of ideas,

cultures between various groups of people would result in a healthy

bonding amongst the population at large. A new culture having a distinct

socio-economic status with an entity of its own would develop. As a result of

this project there would be all-round development of the region.

9.5 ENVIRONMENTAL MANAGEMENT PLANS

Based on the findings of the Environmental Impact Assessment study,

following Environmental Management Plans shall be formulated to mitigate

the adverse impacts and to maximize the positive impacts of the project

construction on the environment:

> Catchment Area Treatment Plan.

> Reservoir Rim treatment Plan

> Resettlement and Rehabilitation Plan.

> Biodiversity conservation plan.

> Compensatory Afforestation Scheme

> Restoration of quarry sites / dumping areas.

> Fish Management Plan.

> Health Management Plan.

> Solid waste Management Plan

> Disaster Management Plan.

> Water Quality Management Plan.

> Free Fuel Scheme

INFRASTRUCTURE & CONSTRUCTION FACILITIES

CHAPTER X

INFRASTRUCTURE 10.0 INTRODUCTION

Sippi Hydroelectric Project is a run of the river scheme proposed to harness hydel

potential of Ringong river, which is a tributary of Siang river. Project involves

construction of Diversion weir and a power house on r ight s ide of river. The

water to power house shall be carried by headrace tunnel. The surge shaft and

penstocks shall be provided in between. Water after, generation of power shall be

carried back by Tail race channel to the river.

The project locations viz. the weir and Power house sites are approachable via

Sippi about 255 KM from Along on Along Tuting road ) . Sippi village is 36 Km

short of Tuting on Along Tuting road. At present there is no road to project

components. The BRO road exist upto Tuting. To reach project site, one has to do

trekking from 36Km D/s of Tuting through thick forest infested with poisonous

snakes. For construction of project, Infrastructure development viz. road & bridges,

school, hospital / health care centre, bank, post office, shopping complex,

temporary / permanent residential buildings, office building alongwith other

utility structures shall be required. Infrastructure shall be developed in accordance

with requirement for taking up construction activit ies of the Project.

However, temporary structures for residential and non residential purpose shall be

developed near the major components of the project during the construction period.

The project township and offices can be constructed at Migging which is at 241 Km

distance from Along. Migging is at about 26 Km from Power House area and Tuting

is about 46 Km from Power House area. The site offices can also be located on the

way from Sippi to project site at a distance of about 5 Km from Sippi. The

Pro ject site is about 270 km from Along, the district headquarter of West Siang

District. The nearest meter gauge rail head is at Murkongselek (Assam) and broad

gauge rail head is at Naogaon (Assam).

The nearest airport is at North Lakhimpur ( Leelabari Airport ) in Assam. The nearest

International Airport is at Guwahati which is capital city of Assam. Inter distances between nearby places are given as follows:

From To Distance in KM Along Tuting road Power House 9

Weir site 11 Tuting 36Migging 17 Along 255 Silapathar 404North Lakhimpur 567 Guwahati 971Pasighat 313 Pangin 228Sippi Village 5 Akajan 519

In order to complete the project within a period of 5 years, proper infrastructure will

be developed at various sites and locations to enable timely execution of project and

also for smooth operations and maintenance of project after commissioning. Infrastructure Construction: Facilities for Sippi H. E. Project as envisaged have been

divided in following categories: 1. Road Communication Network

2. Project headquarters, residential/non-residential complexes.

3. Workshop

4. Stores

5. Explosive Magazine

6. Quality Control Lab

7. Diesel power house

8. Fueling Station

9. Construction power

10. Telecommunication

10.1 ROAD COMMUNICATION NETWORK

10.1.1 Improvement & utilization of National Highway & State Highway

10.1.1.1 National Highway, NH-52

National Highway, NH-52, from Gogamukh to Akajan needs improvement for

transportation of heavy equipment & machinery and generating plant and equipment

of the Project. It is expected that NH-52 authorities at their own cost shall be carrying

out this work. 10.1.2 Approach Road from Akajan to Project Site

The project site near Tuting is connected by 519 kms. long all weather BRTF road

from Akajan. Formation width of road is 5.9 to 6.1 mtrs. with extra widening in bends

are 0.9 mtrs. Existing pavement of road sector is quite insufficient to sustain heavy

load. Maximum longitudinal gradient of road is 1:12 to 1:30. The bridges on the road

are also not sufficient to take the heavy loads. BRTF are upgrading all bridges to class

– 24 to meet the existing load traffic. Widening / improvement of this road, wherever

required, strengthening of culverts and bridges to 70R capacity from Akajan to

Barrage site is required for movement of all heavy equipments. DPR of Siang Middle

HEP has been submitted & is under TEC. After CEA approval, road shall be

strengthened & widened for Siang Middle HEP upto Along. From Along to Migging,

the existing road shall have to be widened / improved, where ever required.

Strengthening of all culverts and bridge to 70R capacity from Along to Tuting shall be

required for movement of all heavy equipments. 10.1.3 Project Roads

In total 15 kms. of road may be required to be constructed for approach to borrow

areas, rock quarries, internal road to Barrage and Power House. Internal road to

township, approach road to work shops stores etc.

10.2 PROJECT HEADQUARTERS, OFFICES AND COLONIES

The construction of Sippi H.E. Project is proposed to be undertaken through highly

mechanized operations with latest construction technology involving minimum man

power. Major construction activities involved are Concrete Barrage , HRT along with

Intake Structures, Spillway, Surge Shaft, Pressure Shaft, Transformer Caverns, Power

House, Draft Tube Gate Gallery and Tail Race and diversion tunnel on the left bank

of Ringong River. All the construction activities may be undertaken with fastest

means to complete the project in time bound schedule. All the major works may be

executed through the Contractors of international repute. Accordingly, departmental

operation may remain restricted to Infra-structural development, overall supervision,

quantity and quality monitoring, financial control and other construction related legal

and safety aspects etc.

The project headquarter, offices and colonies may be constructed at Migging and in

project area. The central workshops, stores, magazine and other non residential

structures required during construction as well as operation & maintenance stage may

be constructed between the barrage site and power house on the left bank of the river.

The entire infrastructure may be utilized during Operation & Maintenance (O&M)

stage of the project also. 10.3 WORKSHOP

10.3.1 Central Workshop

Central Workshop for heavy earth moving equipment and transport vehicles will

be located near the Project site. The workshop may comprise facilities for the

engine repairs and overhauling, transmission & torque convector repair shops,

electrical shops, machine shop. tyres repair shop, welding and fabrication shops,

maintenance yard, offices and canteen etc. The workshop may be adequately

fenced with control of operation through entry and exit gates. The main parking

and maintenance yard may be created within this central workshop.

10.4 STORES AND EXPLOSIVE MAGAZINE

10.4.1 Cement, Steel and Miscellaneous Construction Materials

The main store for cement, steel and other materials including chemicals may be

located at Pro ject s i te and may cater to the complete requirement of the entire

project. Steel and other store items like bitumen etc., which do not require covered

area would be kept outside in open. 10.4.2 Spare Parts and Generating Unit Items

Project will have various types of plants, equipment, vehicles etc. in addition to the

parts of the main generating units. The storage for above material may be done at

Power house site. 10.5 EXPLOSIVE MAGAZINES

Major project activities of Ringong H.E. Project shall be confined in area where

construction activities of Diversion Tunnels, Diversion weir, Intake works,

HRT, Powerhouse, Roads, proposed quarries etc. are to be carried out. For this

purpose explosive magazine of a total capacity of 100 MT and proportionate

capacity of detonators have been planned. Explosive magazine for the same may be

constructed near Kigot 10.6 QUALITY CONTROL & MISCELLANEOUS LABORATORY

One quality control laboratory may be established at Barrage site. It will have

facilities of testing of Cement, Aggregate and concrete. 10.7 DIESEL POWER HOUSE (STANDBY SOURCE)

At present, there is a micro hydel project namely Sikut Micro Hydel of 100 KW near

to Tuting on nalla Sikut. This micro hydel is insufficient to cater to needs of even

Tuting. Hence, as a standby source one Diesel Powerhouse of capacity 2X500 KVA

capacity at each of the location viz. Barrage site and Power House may be installed

for stores and offices. For administrative office and residential complex, 2X500 KVA

and 2X320 KVA D.G. Sets may be installed as standby source to power supply.

10.8 FUELING STATION

One no. fueling station for providing POL to project vehicles / equipments is

proposed to be located at Migging village. The fueling station shall have storage

capacity of 30 KL of Petrol and 100 KL of HSD due to remoteness and possibility of

road closing / hill slide during rainy season.

10.9 CONSTRUCTION POWER

The main activity of construction shall be at powerhouse, tunnels and the Barrage area.

The power requirement has been divided in two parts:

1. Construction power for main works: Since there is no grid power available in

the region and therefore total requirement for the construction power has to be

met by the DG sets. The estimated requirement of construction power shall be

around 6 MW.

2. Power requirement for construction of infrastructure/ department works such as:

a. Residential and non-residential buildings

b. Departmental works

c. Commercial complexes

d. Street lighting 10.10 TELECOMMUNICATION

There is no reliable telecommunication network in the region. Telephone exchange of

BSNL at Tuting is totally unreliable. For good communication during construction of

the project, Radio communication ( multi channel) in addition to local connection

from BSNL exchange are required.

Due to frequent heavy rain in this area there are always possibilities of land slides

leading to barrageage of communication system. As such provision of wireless system

may be made as a standby arrangement.

Project shall have to make its own arrangement of V-set communication, and LDST.

Besides inmarset shall also be kept as a means of telecommunication.

CHAPTER – XI

CONSTRUCTION PLANNING & SCHEDULE

CHAPTER XI

CONSTRUCTION PLANNING AND SCHEDULE

The Equipment Planning & Construction Methodology of Sippi H.E. Project (3X32

MW), in Siang Basin has been developed on following considerations.

1. The project construction period has been considered as five years after

completion of Stage I & II activities.

2. Available Geological Data at PFR stage.

3. Requirement of Construction Equipment has been planned to handle the

quantities worked out on the basis of preliminary layout

4. Five months rainy season has been considered while planning surface works. 11. Construction Methodology: 11.1 Infrastructure Works.

The main infrastructure development is proposed to be carried out in period of 12

months. During infrastructure period Land Acquisition, construction of approach

roads, bridges & culverts will be taken up. Arrangement of construction power will

be undertaken. Critical components of project would be started after construction of

approach roads. Platform to accommodate batching plant, stores for construction

material, site workshop offices and other buildings (residential/non residential)

colonies will also be developed in infrastructure period. Crawler Dozer, Loader cum

Excavator, Motor Grader, Air compressor, Road Roller etc. are proposed for

deployment during infrastructure stage. 11.2 Diversion of River

The construction of 1 no. 6.5m finished diameter, D shaped 600m long diversion

tunnel would be carried out by heading & benching method from both faces.

Excavation of Diversion Tunnels will be carried out with 2 Boom drill jumbo, Air

Track/Wagon Drill, hack hammer, 2.5 cum side dump loader and 20/25T L P

Dumpers Diversion tunnel excavation, concreting and HM work would be completed

in 15 months. The concreting equipment being proposed are 80 cum/hr Batching &

Mixing plant, Concrete pump, Transit mixer, Shotcrete machine, Grout pump and

shutters etc. The aggregate required for B&M Plant will be processed by the plant

proposed in Barrage. U/s Coffer dam would be constructed immediately after

construction of diversion tunnel within a period of 4 months to divert the river.

However river bed excavation would be taken up after completion of 1st stage of

coffer dam in two months. Repair work of coffer dam would be done twice in two

months after each rainy season. 11.3 Diversion weir

After diversion of river, excavation of river bed & foundation treatment would be

carried out in 3 months. Excavated material will be handled by 2.0 cum Hyd.

Excavator and 25T Rear dumpers. Concreting of w e i r & HM work would be

carried out in further 28 months. Concreting would be catered by deploying 2

nos. Tower Cranes having capacity of 7.2 T at 40m radius, 1 no. 80 cum/hr Batching

& Mixing plant installed at D/T and 1 no. another 250Cum/hr Batching & Mixing

Plant, which will also cater the requirement of intake Desilting chambers and part of

HRT and 650 TPH Aggregate Processing plant which will cater the requirement

of Diversion tunnel, Intake structure, Desilting chamber and the Diversion weir. 11.4 Intake Structure, Desilting Chamber, Silt Flushing tunnel

1 Nos. intake and 3 nos. Desilting chamber of size 100m X 8m X 12m would be

excavated in 18 months. Excavation of Desilting Chamber would be taken up from

adits to desilting chamber. Initially tunnels of 6.0 m dia would be excavated by full

face method to the full length of Desilting Chambers. Thereafter it will be expanded

side wise to the full width of desilting chambers resulting in desilting chamber dome.

Mucking of excavated material would be done through the adits of desilting chamber.

After the excavation of desilting chamber, concreting will be carried out. Excavation

of silt flushing tunnel & gate operation chamber would be a parallel activity. The

equipment to be deployed are two boom drill jumbo, Jack hammer, wagon drills, air

compressors, side dump loader, L .P. dumpers, concrete pump, transit mixers etc.

However concreting requirement of intake tunnel & desilting chamber would be

catered by Batching & Mixing Plant installed at Barrage.

11.5 Head Race Tunnel

Initially construction of adits for HRT would be carried out in 4 months. Thereafter

excavation of 6.0 m finished diameter 8 km long D shaped Head Race Tunnel would

be done by full face drilling & Blasting method in 24 months. Excavation would be

carried out by deploying three set of equipment i.e. single boom drill jumbo 1.0 cum

side dump loader and 20/25T L.P. dumper. Concreting will be done by deploying

concreting equipment i.e. Concrete pump, Transit Mixer in 18 months. 1 no. 30

cum/hr Batching & mixing plant and 50 TPH aggregate processing Plant is proposed

at HRT. 11.6 Surge Shaft:

Initially construction of approaches for surge shaft would be done in 4 month.

Thereafter excavation of 15 m diameter 30 m high, Surge shaft would be taken up

from top of surge shaft. Excavation of Surge Shaft would involve pilot hole drilling,

reaming of pilot hole & enlargement of reamed hole. Raise borer, Wagon Drill, 50 HP

Dozer, 2.5 cum, side Dump Loader & 20/25t LP Dumpers etc. will be deployed for

excavation of Surge shaft, Concreting would be completed employing 2m shutter,

concrete pump, 60 cum/hr Batching & mixing plant and 100 TPH aggregate

processing Plant would be deployed to cater the requirement of surge shaft, part of

HRT and part of pressure shaft. Excavation and concreting of surge shaft would be

completed in 40 months. 11.7 Penstock:

Before erection of penstock first stage concrete of Anchor Block and saddels support

will be done and after erection second stage concreting will be done. For excavation

and concreting approach road will be constructed, would be completed in 4 months. 11.8 Power House

3 X 32 MW (96MW) surface power house (70m (L) 22m (W) X 40m (H)) excavated

in 06 months. The equipment to be deployed for excavation are jack hammers, air

compressors, loader, excavators, tippers/dumpers, etc. Concreting of Power house

would be done by deploying Concrete pump, 30 cum/hr Batching & Mixing Plant and

150TPH aggregate processing Plant which will also cater the requirement of part of

Anchor blocks and TRC. Installation & Testing of Machine would be undertaken in

such a manner that Project get commissioned in 60th month from the start of Project

construction.

11.9 Tail Race Channel:

1 no. 500 m long Tail Race Channel will be excavated in 06 months. Excavation of

Tail Race Channel would be carried out by open surface drilling & blasting method

with two Jack hammer with leg pusher, .95 cum side dump Loader, 10 t LP Dumper

etc. Concrete lining of TRC would be catered by concrete pump, transit Mixer,

Batching & Mixing Plant and aggregate processing Plant installed at Power House.

CHAPTER – XII

ECONOMIC EVALUATION

CHAPTER - XIII

ECONOMIC EVALUATION 12.0 ECONOMIC EVALUATION

The Project has been contemplated as a run-off the river scheme on river

Ringong. The project is estimated to cost Rs.786.89 crores including

IDC.

Sale price of energy generated at powerhouse bus bars has been worked

out as 3.89 Rs./unit with free power to home state . 12.1 ECONOMIC JUSTIFICATION:

The energy generation of the project with an installed capacity of 96 MW

has been estimated at GHWin a 90% dependable year. 12.2 COST ESTIMATES AND PHASING OF EXPENDITURES

The cost of construction of the project has been estimated with a

construction schedule of 5 years including 1 years for Infrastructure works.

12.3 PHASING OF EXPENDITURE

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

anticipated construction programme. The phasing of expenditure

without IDC for the present cost is shown as below:

Year Amount(in crores)

Ist Rs.65

IInd Rs. 130

IIIrd Rs. 190

IVth Rs. 190

Vth Rs. 65 Total Rs 640.0 Crores(excluding IDC)

INTEREST DURING CONSTRUCTION (IDC)

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

have been calculated with 70:30 debt equity ratio and at the rate of 11.75% interest

on loan. The estimated IDC with estimated present cost is Rs 146.89 Crores

COST OF ENERGY GENERATION

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

in a 90% dependable year based upon following assumptions.

1. Debt-equity ratio 70: 30

2. Annual interest rate on loan 11.75%

3. Return on equity 16%

4. Annual interest rate on working capital 10.0% 5. O&M Charges 1.5% of Project Cost

6. Free power to Home State 12% of the energy available after

losses

7. Depreciation considered 1/12th of loan amount during loan repayment period.

The levellised tariff of the Project at present day cost works out to be Rs. 3.84 Per Unit.

 

10 daily discharge series for PANGO HEP (Catchment Area 840 Sq.Km) Month 10-daily 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

Jun I 98.17  131.02  115.77  86.13  91.67  100.25  109.23  140.51  86.89  92.16  94.28  107.37  125.44 II 135.79  169.39  157.13  104.11  111.39  80.51  170.41  142.01  115.75  113.16  118.74  104.85  125.44 III 188.95  185.11  124.59  142.03  121.64  93.79  139.49  142.21  125.91  124.32  118.01  118.67  130.62 

Jul I 114.70  267.57  129.82  171.98  109.05  90.63  162.07  154.85  102.53  180.15  177.52  188.97  115.21 II 124.54  199.71  133.54  177.45  132.05  82.05  192.41  195.27  99.80  153.31  136.56  149.75  149.89 III 120.84  182.12  121.12  127.27  196.07  128.03  171.78  178.49  109.32  185.87  156.72  130.64  176.40 

Aug I 118.15  111.73  220.28  147.32  139.42  98.37  136.42  157.04  185.02  197.83  125.79  109.70  129.32 II 91.58  88.19  294.72  156.30  108.24  99.67  88.07  168.92  160.81  214.11  178.19  126.40  132.74 III 61.03  148.27  124.32  158.47  134.06  102.73  102.39  194.40  210.10  156.35  258.38  130.46  151.23 

Sep I 109.20  160.58  91.91  144.28  120.80  119.03  107.98  162.94  176.87  208.60  194.78  139.40  144.96 II 136.18  158.94  96.90  145.25  155.85  140.62  128.70  155.03  252.55  138.23  139.94  122.91  156.24 III 112.44  85.04  102.97  120.08  136.36  145.11  87.65  113.33  141.27  162.10  110.32  115.14  141.99 

Oct I 93.52  150.38  94.20  116.40  116.66  78.40  83.64  94.58  114.08  116.12  116.48  115.63  139.46 II 71.32  100.94  73.04  96.61  95.78  94.80  92.03  87.99  88.23  97.17  89.91  88.54  107.42 III 62.73  51.57  71.42  86.14  94.09  71.37  92.41  83.70  60.32  90.85  85.76  80.28  78.52 

Nov I 46.58  38.18  37.43  51.70  56.33  37.43  95.88  81.75  31.38  59.29  42.62  51.64  40.46 II 36.95  28.47  28.08  38.18  31.36  33.02  59.13  74.38  34.65  45.63  42.08  40.71  31.91 III 46.23  23.89  22.50  34.91  25.15  25.13  50.11  60.66  26.06  37.41  37.95  37.00  27.00 

Dec I 29.61  26.57  24.81  30.60  46.26  19.79  37.04  54.49  24.57  31.63  30.91  24.25  24.14 II 25.15  22.20  15.49  33.92  28.09  17.22  24.21  46.32  21.84  28.81  27.31  21.60  21.43 III 21.56  21.88  13.46  30.45  23.37  20.74  16.19  44.28  21.21  24.18  23.94  19.21  18.33 

Jan I 17.14  21.51  17.74  26.68  18.97  17.47  13.61  38.46  14.13  20.83  21.32  15.06  16.33 II 15.18  16.73  14.92  22.57  17.79  17.44  12.60  34.15  12.59  21.15  18.28  15.08  14.75 III 15.03  18.07  14.65  15.11  16.56  14.52  11.80  29.03  10.92  19.04  15.96  16.86  13.20 

Feb I 13.31  23.02  14.21  13.20  17.15  16.26  13.67  21.97  10.02  15.68  18.48  17.42  13.31 II 10.68  19.83  15.27  13.33  16.26  15.20  11.99  20.48  10.68  22.27  16.73  16.73  12.71 III 18.30  20.35  17.70  15.57  24.53  14.86  12.88  22.29  12.84  28.28  16.22  16.99  12.54 

Mar I 18.84  50.54  21.71  20.39  20.74  15.25  15.63  21.10  12.84  26.84  21.37  19.85  20.91 II 19.47  38.13  20.40  22.20  29.77  15.12  23.08  21.86  21.04  36.99  23.30  15.08  19.75 III 28.47  38.72  19.06  24.21  38.35  21.08  21.83  18.50  22.57  48.39  27.39  22.64  27.73 

Apr I 30.75  42.66  22.31  34.31  36.11  66.07  24.05  20.37  33.90  47.25  28.84  30.80  32.36 II 35.84  64.07  22.31  35.30  60.04  93.11  32.71  26.41  52.95  54.22  52.68  39.11  44.04 III 38.55  112.45  24.81  33.08  49.02  80.39  77.06  46.34  42.68  55.63  55.65  50.75  31.23 

May I 82.71  87.20  58.91  63.64  72.25  88.37  72.25  53.44  72.75  80.30  79.75  79.86  87.29 II 75.30  86.74  71.70  75.42  86.92  104.98  64.27  70.08  72.27  90.72  77.96  76.29  84.48 III 59.06  76.00  88.26  74.84  97.61  123.98  89.88  76.37  79.84  110.18  96.92  93.99  85.80 

 

 

Month 10-daily 1991‐92  1992‐93  1993‐94 2000‐01 2001‐02 2002‐03 2003‐04 2004‐05  2005‐06 2006‐07 2007‐08 2008‐09Jun I 103.98  75.46  86.92  106.15  179.40  77.07  76.97  84.51  91.38  115.26  191.35  142.89 

II 138.35  82.67  98.49  111.06  111.89  109.61  107.69  92.72  100.65  120.16  207.40  149.24 III 121.04  137.63  104.37  101.64  234.70  131.18  167.43  133.54  121.89  188.48  125.94  146.63 

Jul I 227.50  122.92  125.79  181.55  84.08  187.11  248.57  127.96  99.17  185.48  136.74  160.95 II 190.70  106.70  110.84  226.75  230.29  124.48  202.82  154.08  151.95  181.94  232.01  204.07 III 131.11  99.02  118.72  165.96  226.68  288.77  123.07  96.17  111.91  178.81  345.70  216.11 

Aug I 190.16  92.56  179.59  199.35  150.06  101.28  102.85  80.57  149.91  99.35  152.21  116.57 II 174.65  85.42  169.47  193.17  155.56  128.84  175.63  56.37  126.48  66.60  185.34  134.70 III 125.71  120.30  151.88  193.96  282.12  81.55  113.87  93.86  208.36  163.34  122.07  147.91 

Sep I 118.80  109.94  108.96  211.93  216.02  62.02  155.51  111.14  98.44  127.62  202.80  135.88 II 112.56  112.93  108.51  201.99  153.45  79.22  121.39  55.13  53.61  221.25  160.53  104.19 III 106.84  93.49  111.57  167.26  109.43  102.75  115.64  94.02  93.90  143.71  69.68  76.10 

Oct I 89.46  86.02  105.27  89.95  95.54  88.34  199.33  86.18  55.56  133.11  101.02  80.09 II 82.62  77.25  87.01  102.81  72.20  55.61  82.78  59.75  34.88  122.53  104.07  51.41 III 71.55  69.86  73.56  71.17  58.50  47.74  65.03  31.69  50.20  60.96  70.91  55.58 

Nov I 28.77  20.69  28.28  42.30  48.69  38.79  42.10  23.56  33.50  43.74  51.47  41.35 II 23.80  18.37  23.21  47.29  37.11  36.46  38.60  16.82  27.43  38.83  45.48  28.21 III 20.03  17.08  19.99  38.60  34.69  23.00  40.27  17.38  22.55  56.63  28.86  24.73 

Dec I 16.67  15.77  14.00  32.78  23.35  20.46  23.73  14.82  24.12  41.39  27.20  24.78 II 14.04  13.31  12.47  32.09  19.14  17.46  32.20  12.45  22.46  38.59  28.46  21.02 III 13.81  11.15  11.67  26.87  17.99  17.15  30.09  12.95  21.21  29.93  24.01  16.69 

Jan I 12.19  14.38  10.48  23.94  16.09  13.48  12.08  12.06  8.86  21.75  26.62  18.26 II 11.99  13.07  10.54  19.92  16.07  12.02  10.81  11.09  7.82  24.87  19.04  19.19 III 10.62  10.61  10.18  22.80  18.90  12.13  11.09  10.08  8.12  27.97  25.09  21.13 

Feb I 11.33  10.02  10.43  24.37  15.35  12.84  10.16  11.27  9.43  35.43  19.45  20.53 II 10.10  11.57  10.12  19.36  17.33  13.85  10.77  18.63  9.30  27.63  24.32  16.31 III 10.53  11.41  10.36  27.43  18.44  15.98  12.40  23.54  22.57  27.52  22.91  28.88 

Mar I 11.02  10.38  10.40  27.25  18.65  17.53  20.12  27.71  24.81  38.81  23.58  31.48 II 11.52  11.03  10.70  22.91  28.08  33.53  20.39  40.01  36.99  64.24  49.70  38.01 III 15.22  15.20  26.84  34.16  41.26  32.43  35.38  53.77  49.05  82.23  64.03  32.41 

Apr I 23.71  16.41  15.38  57.97  34.02  60.71  17.17  60.45  61.18  127.19  70.68  63.78 II 32.90  21.34  20.59  115.24  69.45  52.25  25.57  69.61  75.59  101.11  95.92  87.43 III 31.64  25.56  30.39  84.39  144.44  76.38  37.73  67.98  91.33  121.48  106.93  107.63 

May I 63.11  73.67  79.01  120.44  66.00  85.69  41.27  62.08  81.51  89.59  105.46  72.32 II 69.92  81.28  97.26  122.23  73.59  75.47  45.43  76.97  92.17  151.28  100.21  79.32 III 68.04  68.55  123.76  137.00  96.95  75.46  65.01  66.60  108.27  208.60  108.27  89.50 

  

 

10 daily discharge series for SIPPI HEP (Catchment area 732 Sq.km) Month  10‐daily  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

Jun I  85.50  114.12  100.84  75.02  79.84  87.32  95.14  122.38  75.68  80.27  82.12  93.52  109.26 II  118.27  147.54  136.86  90.68  97.02  70.13  148.42  123.69  100.82  98.56  103.43  91.33  109.26 III  164.57  161.23  108.52  123.70  105.95  81.69  121.50  123.87  109.67  108.28  102.79  103.36  113.77 

Jul I  99.91  233.05  113.08  149.80  94.98  78.94  141.17  134.87  89.31  156.91  154.62  164.59  100.35 II  108.47  173.95  116.31  154.56  115.02  71.47  167.59  170.08  86.92  133.54  118.95  130.43  130.56 III  105.25  158.63  105.49  110.85  170.78  111.52  149.62  155.46  95.22  161.89  136.50  113.79  153.65 

Aug I  102.91  97.32  191.86  128.31  121.44  85.68  118.82  136.78  161.15  172.31  109.56  95.55  112.63 II  79.77  76.81  256.70  136.14  94.28  86.82  76.71  147.13  140.07  186.49  155.21  110.09  115.61 III  53.15  129.15  108.28  138.03  116.77  89.48  89.18  169.33  183.00  136.18  225.05  113.63  131.72 

Sep I  95.11  139.86  80.05  125.66  105.22  103.68  94.05  141.92  154.05  181.69  169.65  121.42  126.26 II  118.61  138.44  84.40  126.52  135.74  122.48  112.10  135.03  219.97  120.40  121.89  107.05  136.09 III  97.93  74.07  89.69  104.59  118.77  126.39  76.34  98.71  123.05  141.19  96.09  100.29  123.67 

Oct I  81.45  130.98  82.05  101.39  101.61  68.28  72.85  82.38  99.37  101.14  101.45  100.71  121.47 II  62.12  87.92  63.62  84.15  83.42  82.57  80.16  76.64  76.84  84.64  78.31  77.12  93.56 III  54.64  44.92  62.21  75.03  81.95  62.16  80.49  72.90  52.54  79.13  74.70  69.92  68.39 

Nov I  40.57  33.26  32.60  45.03  49.06  32.60  83.51  71.20  27.34  51.64  37.13  44.98  35.24 II  32.18  24.80  24.46  33.26  27.32  28.76  51.50  64.78  30.18  39.74  36.65  35.46  27.79 III  40.26  20.81  19.60  30.41  21.91  21.89  43.64  52.83  22.70  32.58  33.06  32.23  23.51 

Dec I  25.79  23.14  21.61  26.65  40.29  17.24  32.26  47.46  21.40  27.55  26.92  21.12  21.02 II  21.91  19.34  13.50  29.54  24.47  15.00  21.09  40.34  19.02  25.09  23.79  18.82  18.67 III  18.78  19.06  11.72  26.52  20.36  18.07  14.10  38.57  18.47  21.06  20.85  16.73  15.97 

Jan I  14.93  18.73  15.45  23.24  16.52  15.22  11.86  33.50  12.31  18.15  18.57  13.12  14.23 II  13.22  14.57  12.99  19.66  15.50  15.19  10.97  29.74  10.96  18.42  15.92  13.14  12.85 III  13.09  15.74  12.76  13.16  14.42  12.65  10.28  25.29  9.51  16.59  13.90  14.68  11.49 

Feb I  11.59  20.05  12.38  11.49  14.94  14.16  11.91  19.14  8.73  13.66  16.10  15.17  11.59 II  9.30  17.27  13.30  11.61  14.16  13.24  10.44  17.84  9.30  19.40  14.57  14.57  11.07 III  15.94  17.72  15.41  13.56  21.37  12.95  11.22  19.42  11.19  24.63  14.13  14.80  10.93 

Mar I  16.41  44.02  18.91  17.76  18.07  13.28  13.61  18.38  11.19  23.38  18.62  17.29  18.21 II  16.96  33.21  17.77  19.34  25.93  13.17  20.10  19.04  18.33  32.22  20.29  13.14  17.20 III  24.80  33.73  16.60  21.09  33.40  18.36  19.01  16.11  19.66  42.15  23.85  19.72  24.15 

Apr I  26.78  37.16  19.43  29.89  31.45  57.54  20.95  17.74  29.53  41.16  25.12  26.83  28.18 II  31.22  55.81  19.43  30.75  52.30  81.10  28.49  23.01  46.12  47.22  45.89  34.07  38.36 III  33.58  97.94  21.61  28.81  42.70  70.02  67.12  40.36  37.17  48.46  48.47  44.20  27.20 

May

I  72.04  75.95  51.31  55.43  62.93  76.97  62.93  46.55  63.36  69.94  69.46  69.56  76.03 II  65.59  75.55  62.45  65.70  75.71  91.43  55.98  61.04  62.95  79.02  67.90  66.45  73.58 III  51.44  66.20  76.87  65.19  85.02  107.98  78.28  66.52  69.54  95.96  84.41  81.86  74.73 

 

 

Month  10‐daily  1991‐92  1992‐93  1993‐94 2000‐01 2001‐02 2002‐03 2003‐04 2004‐05  2005‐06 2006‐07 2007‐08 2008‐09

Jun     

I  90.57  65.73  75.71  92.46  156.26  67.13  67.04  73.61  79.59  100.40  166.67  124.46 II  120.51  72.00  85.79  96.73  97.46  95.47  93.80  80.76  87.66  104.66  180.64  129.99 III  105.43  119.88  90.90  88.53  204.43  114.26  145.83  116.31  106.16  164.16  109.70  127.71 

Jul     

I  198.16  107.07  109.56  158.13  73.23  162.97  216.51  111.45  86.37  161.56  119.10  140.19 II  166.10  92.93  96.54  197.50  200.58  108.43  176.65  134.21  132.35  158.47  202.08  177.75 III  114.19  86.25  103.41  144.55  197.44  251.52  107.19  83.77  97.48  155.75  301.10  188.23 

Aug     

I  165.63  80.62  156.42  173.63  130.70  88.22  89.58  70.18  130.57  86.53  132.58  101.53 II  152.12  74.40  147.61  168.25  135.50  112.22  152.97  49.10  110.17  58.01  161.43  117.32 III  109.50  104.78  132.29  168.94  245.72  71.03  99.18  81.75  181.49  142.27  106.32  128.83 

Sep     

I  103.47  95.76  94.91  184.59  188.15  54.02  135.45  96.80  85.75  111.16  176.64  118.35 II  98.04  98.36  94.51  175.93  133.65  69.00  105.73  48.02  46.69  192.71  139.82  90.75 III  93.06  81.43  97.18  145.68  95.32  89.49  100.72  81.89  81.79  125.17  60.69  66.28 

Oct     

I  77.92  74.92  91.69  78.34  83.21  76.94  173.62  75.07  48.40  115.94  87.99  69.76 II  71.96  67.29  75.79  89.55  62.89  48.44  72.10  52.04  30.38  106.72  90.65  44.78 III  62.32  60.85  64.07  61.99  50.95  41.58  56.64  27.60  43.73  53.10  61.76  48.41 

Nov     

I  25.06  18.02  24.63  36.85  42.41  33.79  36.67  20.52  29.17  38.10  44.83  36.02 II  20.73  16.00  20.21  41.19  32.32  31.76  33.62  14.65  23.89  33.82  39.61  24.57 III  17.45  14.88  17.41  33.62  30.21  20.03  35.08  15.14  19.65  49.32  25.14  21.54 

Dec     

I  14.52  13.74  12.20  28.55  20.34  17.82  20.67  12.91  21.01  36.05  23.69  21.58 II  12.23  11.59  10.86  27.95  16.67  15.21  28.05  10.85  19.56  33.61  24.78  18.31 III  12.03  9.71  10.16  23.40  15.67  14.94  26.21  11.28  18.47  26.07  20.91  14.54 

Jan     

I  10.62  12.52  9.12  20.85  14.02  11.74  10.52  10.50  7.72  18.94  23.19  15.90 II  10.44  11.39  9.18  17.35  14.00  10.47  9.41  9.66  6.81  21.66  16.59  16.72 III  9.25  9.24  8.86  19.86  16.46  10.57  9.66  8.78  7.07  24.36  21.85  18.41 

Feb     

I  9.87  8.73  9.09  21.22  13.37  11.19  8.85  9.82  8.21  30.86  16.94  17.89 II  8.80  10.08  8.82  16.86  15.09  12.06  9.38  16.23  8.10  24.06  21.19  14.21 III  9.17  9.93  9.03  23.89  16.07  13.92  10.80  20.50  19.66  23.97  19.95  25.15 

Mar     

I  9.60  9.04  9.06  23.74  16.25  15.27  17.53  24.13  21.61  33.81  20.54  27.41 II  10.03  9.61  9.32  19.95  24.46  29.20  17.76  34.85  32.22  55.95  43.29  33.10 III  13.25  13.24  23.38  29.75  35.93  28.24  30.81  46.83  42.72  71.63  55.77  28.23 

Apr     

I  20.65  14.29  13.40  50.49  29.63  52.88  14.96  52.65  53.29  110.78  61.57  55.55 II  28.65  18.59  17.93  100.38  60.49  45.51  22.28  60.63  65.84  88.07  83.55  76.15 III  27.56  22.26  26.47  73.50  125.81  66.52  32.86  59.21  79.55  105.81  93.14  93.74 

May     

I  54.97  64.17  68.82  104.90  57.48  74.64  35.95  54.07  70.99  78.03  91.85  62.99 II  60.90  70.79  84.72  106.46  64.09  65.74  39.57  67.04  80.28  131.76  87.29  69.09 III  59.26  59.70  107.79  119.33  84.44  65.73  56.63  58.01  94.30  181.69  94.30  77.96 

  

 

90% Dependable Year Calculation 

Year  Discharge  Rank  Probability  Descending order 

1978‐79  2033  1  0.04  3068.97 1979‐80  2684  2  0.08  3041.02 1980‐81  2220  3  0.12  2978.53 1981‐82  2353  4  0.15  2813.57 1982‐83  2341  5  0.19  2743.18 1983‐84  2085  6  0.23  2684.29 1984‐85  2314  7  0.27  2672.25 1985‐86  2672  8  0.31  2517.44 1986‐87  2337  9  0.35  2454.63 1987‐88  2743  10  0.38  2353.25 1988‐89  2517  11  0.42  2349.01 1989‐90  2231  12  0.46  2341.32 1990‐91  2349  13  0.50  2337.29 1991‐92  2184  14  0.54  2313.99 1992‐93  1718  15  0.58  2310.83 1993‐94  2036  16  0.62  2230.93 2000‐01  2979  17  0.65  2220.28 2001‐02  2814  18  0.69  2184.01 2002‐03  2108  19  0.73  2107.59 2003‐04  2311  20  0.77  2088.24 2004‐05  1809  21  0.81  2084.94 2005‐06  2088  22  0.85  2036.15 2006‐07  3069  23  0.88  2033.32 2007‐08  3041  24  0.92  1809.10 2008‐09  2455  25  0.96  1717.63 

1986‐87 ‐ 50% dependable year   2004‐05 ‐ 90% dependable year  

 

 

 

 

Details of Environmental flows to be released Month‐wise in 90% Dependable Year for Sippi HEP  

Month  10‐daily  River inflow (Cumecs) Env Flow to be 

released (cumec) 

Flows tobe released in % 

Jun  10  I  90.64  25.7 

30% of average flow in monsoon season (June to Sep) of 90% dependable year 

Jul  10  I  110.31  25.7 

Aug  10  I  67.31  25.7 

Sep  10  I  75.92  25.7 

Oct  10  I  51.81  11.59 25% of average flow for Oct, Nov, April &May of 90% 

dependable year Nov  10  I  16.85  11.59 

Dec  10  I  11.73  3.6 

20% of average flow in lean season (Dec to March) of 90% dependable year 

Jan  10  I  9.69  3.6 

Feb  10  I  15.59  3.6 

Mar  10  I  35.43  3.6 

Apr  10  I  57.76  11.59 25% of average flow for Oct, Nov, April &May of 90% 

dependable year May  10  I  59.98  11.59  

 

Power Potential Study for 90% and 50% Dependable Year 

S.No  Generation (MW) 

90% Dependable Year  50% Dependable Year 

Energy (MU)  Incremental Energy  Energy (MU)  Incremental Energy 

1  85  474.49    476.98   

2  86  477.39  2.90  480.61  3.63 

3  87  480.25  2.86  484.19  3.58 

4  88  483.12  2.86  487.77  3.58 

5  89  485.77  2.66  491.35  3.58 

6  90  488.43  2.66  494.98  3.63 

7  91  491.10  2.66  498.61  3.63 

8  92  493.72  2.63  502.05  3.44 

9  93  496.17  2.45  505.39  3.34 

10  94  498.59  2.42  508.78  3.39 

11  95  500.98  2.39  512.12  3.34 

12  96  503.39  2.42  515.50  3.39 

13  97  505.73  2.33  518.85  3.34 

14  98  507.90  2.18  522.23  3.39 

15  99  509.98  2.07  525.57  3.34 

16  100  511.89  1.91  528.79  3.22 

 

 

 

Year wise Energy Calculations Year  Unrestricted energy 

Q=(Gross flow‐‐Env flows) 

Restricted energy (Q=design discharge) 

Absolute energy  (Q= Gross flow) 

1978‐79  484.51  465.16  638.62 1979‐80  688.96  560.49  843.07 1980‐81  543.23  464.91  697.34 1981‐82  584.99  528.91  739.10 1982‐83  581.24  549.53  735.35 1983‐84  500.72  491.02  654.83 1984‐85  572.66  520.02  726.77 1985‐86  685.18  586.30  839.29 1986‐87  579.98  484.99  734.09 1987‐88  707.46  590.09  861.57 1988‐89  636.56  544.95  790.67 1989‐90  546.57  521.86  700.68 1990‐91  583.66  537.46  737.77 1991‐92  531.84  457.24  685.95 1992‐93  385.36  383.31  539.47 1993‐94  485.40  452.38  639.51 2000‐01  781.38  613.98  935.49 2001‐02  729.57  540.73  883.68 2002‐03  507.83  448.32  661.95 2003‐04  571.67  466.03  725.78 2004‐05  414.09  406.59  568.20 2005‐06  501.76  468.86  655.87 2006‐07  809.78  663.66  963.89 2007‐08  801.00  624.43  955.11 2008‐09  616.83  543.50  770.94