1.1 Project Background

1.2 Project Description
1.3 Scope and Details of Works
1.4 Location and Site Map

1.1 Project Background

              The Himachal Pradesh Government had decided to construct a Project namely Koldam Hydroelectric Power Project of 800 MW (4x200 MW) in Bilaspur District. It is situated about 25 km from District HQ on river Satluj and 4 km upstream of Dehar Power Plant. The construction of this project has to be done by NTPC Limited (formerly known as National Thermal Power Corporation Limited), a Govt. of India Undertaking. In this connection an agreement was signed between H.P. Govt. and NTPC on 26 February 2000. The Hon’ble Prime Minister Shri Atal Bihari Bajpai laid the foundation stone on 5 June, 2000.The estimated annual generation of electricity will be 3,054 GWH (90% Dependable year).

              From the Koldam Project alone, Himachal Pradesh will get 12% of the power production free of cost and another 15% at bus-bar rate. The Koldam Project will not only provide suitable compensation to the property and agricultural land owners but also generate employment opportunities for them. The Koldam Project, along with other such projects, shall bring prosperity in Himachal Pradesh, which in turn, shall contribute to the prosperity of the country.
              Main Dam construction wok was inaugurated on 14 January 2004 by the then CMD Shri C P Jain.
The salient features of Koldam Hydroelectric Power Project are as follows :-

• Main Dam
- Height 167 m
- Crest Level EL.+ 648
- Type Rock & gravel fill with clay core
- Crest Length 474 m
- Crest Width 14 m
- Maximum Reservoir Level EL.+ 646
- Full Reservoir Level EL.+ 642
- Minimum Draw Down Level EL.+ 636
• Diversion Tunnels
- Number / Length 2 nos. (T1 – 900 m. & T2 – 920 m)
- Finished Diameter 14 m ( Horseshoe shaped )
- Design Capacity 6,500 cu m/sec.
• Penstocks
- Number / Type 4 nos. Circular Steel Lined
- Size 6.45 m
- Length 400 m per each
• Power House
- Type of Power House Surface
- Type of Turbine 4 nos. Francis (Vertical)
• Switch Yard
- Type of SW Yard Surface / Conventional Type
- Transmission 400 KV Thro’ 400 KV Line Coming
- Evacuation System Nathpa Jakhri

              Land is being acquired in 68 villages for this project. For the resettlement of the oustees, resettlement with modern amenities is being developed at Kangoo in Sunder Nagar. Similar colonies will be developed for Bilaspur, Karsog, Sunni and Arki. Continuous interaction between State Administration, NTPC and Oustees is being done through Village Development Advisory Committees (VDACS). Public Information Centre (PIC) has been opened at Harnora in Bilaspur, Kyan in Mandi & Sunni.


1.2 Project Description


• Project Title : Koldam Hydroelectric Power Project (4x200MW)
• Project Location : Kyan, P.O. Slapper, Teh. Sunder Nagar, Distt. Mandi (H.P.) 174 403, Himachal Pradesh, India.
• Employer : NTPC Limited (formerly known as National Thermal Power Corporation Limited). (A Government of India Enterprise)
NTPC Bhawan, SCOPE Complex, 7, Institutional Area, Lodhi Road, New Delhi 110 003.
• Engineer : The General Manager (In-charge) Koldam Hydroelectric Power Project, NTPC Limited, P.O. Barmana, Distt. Bilaspur, Himachal Pradesh, India.
• Contractor : Italian-Thai Development Public Company Limited 2034/132-161 New Petchburi Road, Bangkok, 10320, Thailand.
• Contract Package : “Main Civil Works Package I : Dam, Spillway & Power Intake Package Contract CW-2A”
• Contract Agreement Date : 11th February 2004
• Original Contract Value : Rs. 6,645,555,021 (Indian Rupees Six Billion, Six Hundred and Forty Five Million, Five Hundred and Fifty Five Thousand, and Twenty One only.)
• Project Commencement Date : 12th December 2003 (as the date of Issue of LOA)
• Original Contract Period : 1,737 Days, 57 (Fifty seven) calendar months
• Estimated Completion Date
(Rev.3 Updated No.1)
: 7th September, 2010
(Progress Status please refer to Item 2.2: Total Work Progress)


1.3 Scope and Details of Works

              Italian-Thai Development Public Company Limited (ITD) is employed by NTPC Limited (formerly known as National Thermal Power Corporation Limited) for the Koldam Hydroelectric Power Project, Main civil works package I: Dam, Spillway and Power Intake package.

              Works included in this contract are mainly:
• Upstream diversion dyke construction.
• Downstream cofferdam construction.
• Dewatering works between the upstream diversion dyke and downstream cofferdam.
• Excavation, regularization, caulking, grouting, compaction and cleaning works for dam foundation surface preparation and acceptance.
• Upstream cofferdam construction.
• Dam construction.
• Installation of the dam monitoring equipment and dam surveillance during the construction and first impounding. Information on geological and hydro geological aspects, hydrology and climate are indicated in the other documents of contract.
• Power Intake construction, Approach Channel, Spillway and Plunge Pool excavation, slope protection and concrete.
• Power House excavation and slope protection, Switchyard excavation and filling.

1.3.1 MAIN DAM CONSTRUCTION AND UPSTREAM COFFER DAM

1.3.1.1 Main Features of Main Dam
              The main dimensional characteristics of the main dam shall be as follows:
• Type : Rock and gravel fill with impervious central clay core
• Crest of dam : EL.+ 648 m
• Max height of dam above natural ground : 153 m
• Max height of dam above foundation : 167 m
• Crest length : 474 m
• Crest width : 14 m

1.3.1.2 Main Features of Upstream Coffer Dam
              The main dimensional characteristics of the upstream cofferdam shall be as follows:
• Type : Rock and gravel fill with impervious central clay core
• Crest of dam : EL.+ 558 m
• Max height of dam above natural ground : 58 m
• Max height of dam above foundation : 73 m
• Crest length : 243.5 m
• Crest width : 14 m

1.3.2 APPROACH CHANNEL AND EXCAVATION WORKS

              In order to ensure the proper flow conditions of flood water to the spillway weir and, in particular, to allow the stream flow lines to be correctly orientated, major earthworks shall be carried out upstream of the spillway to create Approach Channel. The geometry of this Approach Channel is being optimized in the scale model tests and thus the volumes of these earthworks are subject to revision.



1.3.3 POWER INTAKE
              The power intake structure is designed to connect with all head structures and units as far as the connection with the 4 penstocks.

1.3.4 SPILLWAY
              The spillway for Koldam is a gated spillway located on the left bank of Dam. The main elements of this structure are:
• A concrete weir approximately 132m. wide, with a crest at elevation 625.
• 6 gate bays, each equipped with a radial gate 17.10m wide by 17m high (by H M Contractor).
• A concrete closure section situated on the left bank of the weir with a top surface at elevation 648 , that prevents any bypassing of the gated weir by the left bank.
• A reinforced-concrete chute of total length of approximately 420m, with width varying from 132m at the top to 70 m at the bottom, equipped at the bottom with a flip bucket that forms a jet trajectory at 30? angle to the horizontal.
• This structure shall respect the following operating specification;
      a) Discharge a flow of 11,400 cu.m./sec, which corresponds to the Standard Project Flood, with 5 gates opened and a maximum water level of EL. 641.1
      b) Discharge a flow of 16,500 m3/s, which corresponds to the Probable Maximum Flood, with 6 gates opened and maximum water level of El. 646
      c) The spillway piers shall each have a room containing the radial gate control equipment

1.3.5 POWER HOUSE AND SWITCHYARD EXCAVATION, LEVELING AND GRADING WORKS

1.3.5.1 Power House
• Surface excavation of hard rock & terrace materials, for removal either to dedicated stockpiles, direct to crusher or direct to fill works.
• Slope stabilization of excavated slopes.
• Dewatering of excavations.
• Construction of temporary and permanent access roads.
• Landscaping works, sub-surface drainage, security fencing, gates, etc.

1.3.5.2 Switchyard
• Surface excavation of hard rock and terrace materials, for removal either to dedicated stockpiles, direct to crusher or direct to fill works.
• Slope stabilization of excavated slopes.
• Fill works to create a level platform.
• Temporary drainage and dewatering.
• Access road.
• Subsurface cable duct network, single sized aggregate capping.
• Levelling of platform for handing-over to EM Contractor.

1.3.6 UNDERGROUND GROUTING AND DRAINAGE WORKS
The work is composed of:
• Underground construction works for grouting and drainage galleries.
• All the grouting and drainage works carried out from the galleries.
• Installation of monitoring equipment in the galleries.


1.4 Location and Site Map

              The Koldam Hydroelectric Power Project is located at Satluj River, 4.5 km upstream of Dehar Power Station of Beas Satluj Link Project in Bilaspur District of Himachal Pradesh. The project features will inter alia include a 163 metre high Rock Fill Dam, Spillway, Diversion Structures, Desilting Arrangement, Surface Power House with planned capacity of 800 MW (4x200 MW). The project will utilize a surface drop of 140 metres. Koldam Hydroelectric Power Project has been basically designed as a run-of-the-river scheme.

              The project site is located 4.5 km from the National Highway-21(NH-21), upstream of the existing Dehar Power Plant of BBMB in Himachal Pradesh. It is located at latitude 30? 23’N and longitude 76? 52’E and lies within an active Himalayan Mountain range. The dam is proposed to be located in the narrow gorge of the valley downstream of Kyan village. The nearest railhead is at Kiratpur, approximately 90 km from the project site and nearest airport is Bhunter (Kullu). Another airport is in Chandigarh – a Union Territory.


Figure 1 : Location and Site Map



Figure 2 : Koldam Construction Site (Looking from Upstream of Approach Channel as of 30 June 2008)



Figure 3 : Dam Cross Section Scheme




Tender Scheme

Construction Scheme


Top Plan View


3-D Spillway View

Figure 4 : Construction Model of Koldam Hydro Electric Power (4x200 MW) Project

 
Copyright © 2008 ITD-KOLDAM, All right reserved.
Italian-Thai Development Public Company Limited (J.1479)
Kyan, P.O. Slapper, Teh. Sunder Nagar, Distt. Mandi, Himachal Pradesh, India 174403
Email : admin@itd-koldam.com, Fax : +91 981-6093252