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 catchment area proportion basis.
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 Rs. 435 Crores
Electro Mechanical Works Rs. 180 Crores Sub total (Generation) Rs. 615 Crores Transmission Works Rs. 25 Crores Total (Hard Cost) Rs. 640 Crores Rs. 146.89 Crores IDC Grand Total Rs. 786.89 Crores
1.8 FINANCIAL ASPECTS
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 – 20m Crest level of weir) 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 3nos. Dufour type each 100m long, 8m basins wide and 12m height Total design discharge in each 30.0 cumecs (including 20% flushing) chamber 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% 414.09 GWH dependable year 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 for a length of 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 eir 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 glaciers and s mall str 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 hills on either side of the river. 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 discharge 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 will be collected and gauge station installed at the weir site 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 disposing 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 sill 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 river bed level, it will 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 fee d wa ter to 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 Sluice Gats 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 fitted with steel liner 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. Hoist arrangement will be provided to regulate flow as per requirement.
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 = 96 MW with 20% COL
No. & size of unit = 3units of 32 MW
Type of power house = Surface
Net head = 145 meters
Design discharge per unit = 24.5 Cumecs
Type of Switchyard =220/ 400 KV GIS
Turbine type = Vertical Francis
Speed of turbine = 500 rpm
Generation voltage = 11.0 KV
Transmission voltage = 220/400 KV
GSU Transformer Energy = 3 Nos. , Three-phase
generation in 90%
dependable year with 95% = 462 MU Machine availability
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 145 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 Area in ha Production in MT
1. Paddy 1337 2540.3
2. Maize 134 361.8
3. Millet 252.1 226.8
9.4.4 Horticulture
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 construction 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 right side 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 activities 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 Project 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 36 Migging 17 Along 255 Silapathar 404 North Lakhimpur 567 Guwahati 971 Pasighat 313 Pangin 228 Sippi 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 Project site 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 2008‐09 Jun 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 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 Jun 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 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 Jul 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 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 Aug 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 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 Sep 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 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 Oct 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 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 Nov 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 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 Dec 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 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 Jan 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 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 Feb 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 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 Mar 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 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 Apr 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 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 May 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
Env Flow to be Month 10‐daily River inflow (Cumecs) released Flows tobe released in % (cumec)
Jun 10 I 90.64 25.7 Jul 10 I 110.31 25.7 30% of average flow in monsoon season (June to Sep) of 90% dependable year 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% Nov 10 I 16.85 11.59 dependable year Dec 10 I 11.73 3.6 Jan 10 I 9.69 3.6 Feb 10 I 15.59 3.6 20% of average flow in lean season (Dec to March) of Mar 10 I 35.43 3.6 90% dependable year Apr 10 I 57.76 11.59 25% of average flow for Oct, Nov, April &May of 90% May 10 I 59.98 11.59 dependable year
Power Potential Study for 90% and 50% Dependable Year
S.No Generation 90% Dependable Year 50% Dependable Year (MW) 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 Restricted energy Absolute energy Q=(Gross flow‐‐Env (Q=design (Q= Gross flow) flows) discharge) 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