Standard Scope of Work for Feasibility Studies, Detailed ... · PDF fileStandard Scope of Work...

ICOLD Technical Committee F:

Engineering Activities in the Planning Process for Water Resource Projects

Standard Scope of Work for Feasibility Studies,

Detailed Design and Tender Documents

Draft

June 2015

ICOLD Technical Committee F: Engineering Activities in the Planning Process for Water Resource Projects

Standard Scope of Work for Feasibility Studies, Detailed Design and Tender Documents

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Contents

Task 1: Collection and Review of Existing Data and Reports ............................................ 4 Sub-Task 1-1: Topographic Information ........................................................................... 4 Sub-Task 1-2: Geology, Foundation Conditions, Materials and Seismicity ....................... 4 Sub-Task 1-3: Meteorology, Hydrology and Sediment Transport ...................................... 4 Sub-Task 1-4: Environmental Data ................................................................................... 5 Sub-Task 1-5: Inception Report ........................................................................................ 5

Task 2: Additional Field Investigations.............................................................................. 5 Sub-Task 2-1: Additional Topographic Surveys and Mapping .......................................... 5 Sub-Task 2-2: Geological Field and Laboratory Investigation Programme ....................... 6 Sub-Task 2-3: Additional Hydrological Investigations ....................................................... 7 Sub-Task 2-4: River Sediment Sampling .......................................................................... 7 Sub-Task 2-5: Report on Additional Surveys and Investigations....................................... 7

Task 3: Basic Studies ....................................................................................................... 7 Sub-Task 3-1: Hydrological and Meteorological Study ..................................................... 7 Sub-Task 3-2: Geological and Geotechnical Study........................................................... 8 Sub-Task 3-3: Seismotectonic Study ................................................................................ 8 Sub-Task 3-4: Sedimentation Study ................................................................................. 8 Sub-Task 3-5: Landslide Study......................................................................................... 9

Task 4: Energy Studies .................................................................................................... 9 Sub-Task 4-1: Energy Demand Studies ........................................................................... 9 Sub-Task 4-2: Power Transmission Studies ................................................................... 10 Sub-Task 4-3: Power System Studies ............................................................................ 11

Task 5: Social and Environmental Studies ..................................................................... 11 Sub-Task 5-1: Collection of Baseline Environmental Data .............................................. 12 Sub-Task 5-2: Environmental and Social Scoping and Screening of Selected

Alternatives ............................................................................................. 12 Sub-Task 5-3: Additional Baseline Data Collection ......................................................... 12 Sub-Task 5-4: Environmental Impact Assessment (EIA) ................................................ 12 Sub-Task 5-5: Environmental Mitigation Plan (EMP) ...................................................... 13 Sub-Task 5-6: Social Impact Assessment (SIA) ............................................................. 13 Sub-Task 5-7: Final Report on Environmental and Social Impact Assessment ............... 14

Task 6: Conceptual Design Study .................................................................................. 14 Sub-Task 6-1: Definition of Project Options .................................................................... 15 Sub-Task 6-2: Preliminary Cost Estimates ..................................................................... 15 Sub-Task 6-4: Preliminary Economic Assessment ......................................................... 16 Sub-Task 6-5: Selection of Best Suited Scheme ............................................................ 16 Sub-Task 6-6: Alternative/Comparative Studies of Project Components ........................ 16 Sub-Task 6-7: Drawings ................................................................................................. 17

Task 7: Feasibility Study Report (FSR) ........................................................................... 17 Sub-Task 7-1: Draft Feasibility Study Report .................................................................. 17 Sub-Task 7-2: Final Feasibility Study Report ................................................................. 17

Task 8: Detailed Studies and Calculations ..................................................................... 17 Sub-Task 8-1: Reservoir Simulations ............................................................................. 17 Sub-Task 8-2: Hydraulic Calculations and Definition of Hydraulic Model Test

Requirements ......................................................................................... 18 Sub-Task 8-3: Definition of Installed Capacities and Unit Sizes ..................................... 18 Sub-Task 8-4: Assessment of Seismic Activities and Seismic Design Loads .................. 19



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Sub-Task 8-5: Structural Calculations and Stability Analysis .......................................... 19 Sub-Task 8-6: Emergency Preparedness Action Plan .................................................... 20

Task 9: Detailed Design ................................................................................................. 21 Sub-Task 9-1: Definition of Design Criteria ..................................................................... 21 Sub-Task 9-2: Design of Dam and Appurtenant Structures ............................................ 22 Sub-Task 9-3: Design of Power Intake, Desilting Chambers and Waterways ................. 24 Sub-Task 9-4: Design of Power House ........................................................................... 25 Sub-Task 9-5: Design and Performance Specifications of Hydro-Mechanical

Equipment .............................................................................................. 26 Sub-Task 9-6: Dimensioning and Performance Specifications of Electrical

Equipment .............................................................................................. 27 Sub-Task 9-7: Transmission Line from Power House to Substation ............................... 29 Sub-Task 9-8: Design of Instrumentation and Control, Telecommunication and

SCADA System ...................................................................................... 30

Task 10: Quantity and Cost Estimation .......................................................................... 30 Sub-Task 10-1: Quantity Estimation ................................................................................. 30 Sub-Task 10-2: Construction and Operation Costs .......................................................... 31 Sub-Task 10-3: Environmental and Social Mitigation Costs .............................................. 33 Sub-Task 10-4: Preparation of Final Cost Estimate .......................................................... 33

Task 11: Construction Planning ..................................................................................... 33 Sub-Task 11-1: Definition of Prospective Organisational Project Structure ....................... 34 Sub-Task 11-2: Definition of Best-Suited Construction Methodology ................................ 34 Sub-Task 11-3: Assessment of Required Transport Logistic ............................................ 34 Sub-Task 11-4: Project Construction and Implementation Schedule ................................ 34 Sub-Task 11-5: Risk Analysis ........................................................................................... 35

Task 12: Economic and Financial Analysis .................................................................... 35 Sub-Task 12-1: Economic Analysis .................................................................................. 35 Sub-Task 12-2: Financial Analysis ................................................................................... 36

Task 13: Detailed Project Report (DPR) ........................................................................ 36 Sub-Task 13-1: Draft Detailed Project Report................................................................... 36 Sub-Task 13-2: Final Detailed Project Report................................................................... 37

Task 14: Tender Documents .......................................................................................... 37 Sub-Task 14-1: Definition of Tender Lots ......................................................................... 37 Sub-Task 14-2: Preparation of Part I: “Bidding Instructions” ............................................ 37 Sub-Task 14-3: Preparation of Part II: “General Conditions of Contract” ......................... 38 Sub-Task 14-4: Preparation of Part III: “Special Conditions” ............................................ 38 Sub-Task 14-5: Preparation of Part IV: “Technical Specifications” ................................... 38 Sub-Task 14-6: Preparation of Part V: “Tender Drawings” .............................................. 39 Sub-Task 14-7: Preparation of Part VI: “Bills of Quantities (BoQ)” ................................... 40



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Task 1: Collection and Review of Existing Data and Reports

Sub-Task 1-1: Topographic Information Inter alia, the following information shall be collected

1:50,000 scale maps covering total project area for general planning and field work.

1:10,000 and 1:1,000 scale maps covering the project area

Aerial photographs of the project area, if available.

Digital terrain models, if available

Registers and information on the survey control information, bench marks, monuments, GPS stations, notes and guidelines corresponding to the project area, if available.

Register of national bench marks and grid points and associated co-ordinates and elevations and corresponding notes and guidelines for use.

Bathymetric and river bank information relating to existing river gauging stations, as available from the appropriate authorities.

Sub-Task 1-2: Geology, Foundation Conditions, Materials and Seismicity Collection of all pertinent geological, tectonic, geotechnical materials and seismic information. Through fieldwork and desk studies this information will be checked for its completeness and validity in order to establish a database for the project and the basis for any additional investigations. The following data shall be collected:

Mapping of regional geology and tectonics,

Mapping of surface geology and geomorphology,

Literature and research documentation on regional geology,

Records and results of previous site investigations and drilling programmes, if any,

Results from previous laboratory analyses,

Records of seismic activity in the region.

Sub-Task 1-3: Meteorology, Hydrology and Sediment Transport For design of reservoir, power plant, spillway and outlet works as well as for environmental assessment the following hydro-meteorological data will be collected:

Average net evaporation values for each month of the year

Sequences of monthly inflow

Flood peak frequency distribution for the design of river diversion works and the programming of construction

PMF flood hydrographs for the design of spillways

Details of rain gauge and river flow gauge network for design and improvement of Flood Warning System.

Monthly flows to assist with the assessment of environmental impacts downstream of proposed schemes

Hydrographs of flood flows on tributaries downstream of the proposed scheme to assist with the definition of operating rules for provision of compensation releases

Baseline water quality data downstream of the project site to assist with the assessment of environmental impacts

Catchment sediment yields and trap efficiency



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Sub-Task 1-4: Environmental Data Besides engineering requirements for topographical, hydrological and other data, described earlier, additional data will be required to be reviewed for an assessment of environmental constraints and preliminary reporting. Data is accessible from the following principal sources:

Arial photography

Satellite images

Topographic maps

Soil maps

Geological maps

Vegetation maps

Hydrological maps

Meteorological data

Land use data

Identification of botanical specimen

Identification of other biological specimens

Sub-Task 1-5: Inception Report On conclusion of Task 1 an Inception Report summarising the work carried out and the conclusions gained will be prepared. The contents of the report include:

Detailed Work Programme based on review of existing data/ Reports.

Status of mobilization i.e. - Establish / furnish office, - Procure office equipment, - Arrange Transport, - Mobilize Staff.

List of Additional data collection/generation.

Any other item of interest

Task 2: Additional Field Investigations The necessity for additional field investigations and laboratory tests results from the fact that the preparation of Feasibility Study Report and the Detailed Project Report will require more detailed data and a higher degree of accuracy than the ones available from the previous studies, if any.

Sub-Task 2-1: Additional Topographic Surveys and Mapping After collection and review of the existing topographic data (see Task 1-1), the Consultant will identify the requirement for additional topographic survey and establish a programme for the topographic works needed for the feasibility and detailed design and the preparation of the tender documents. This programme will define the sites to be surveyed and describe the survey methods to be applied. It will also comprise the quantities of work, activity schedules for the different parts of the surveys and technical standards for the surveys to be executed by specialized contractors.



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Sub-Task 2-2: Geological Field and Laboratory Investigation Programme Additional geotechnical investigations are required to complete the existing information for preparation of the detailed design. These investigations may include drilling, exploratory adits, geophysical surveys, field and laboratory tests. Minor investigations and surveys could be carried out directly under the responsibility of the Consultant, however, it is normally assumed that most investigations like core drilling, test pit sinking, driving of exploratory galleries, etc. are separately contracted by the Client. Before determining the additional investigation programme the Consultant will review all collected information on geology, tectonics and geotechnical aspects with the purpose of establishing a geo-data base for the project. This shall include satellite imagery and aerial photos covering the project area and close vicinity, which may be very useful tools for identifying:

Major fault zones, lineaments, weakness zones,

General pattern and orientation of discontinuities,

Form and orientation of regional morphological features,

Boundaries of geological formations and petro-graphical differences,

Slope instabilities, old and recent slope failures,

Areas of erosion and of sedimentation etc.

The site investigation program defined by the Consultant might require modifications as new conclusions may arise during the execution of surveys. Such changes could be caused by shifting of structures to different locations during the project optimisation or by highly unfavourable results of surveys. The programme may include:

Surface Investigations and Mapping

Auger Drilling and Pitting

Core Drilling including Testing In the course of drilling, in-situ tests will be performed in the boreholes, such as:

Standard Penetration Tests

Constant or Falling Head Tests

Lugeon Tests

Exploratory Adits Excavation, survey and geological mapping of the adits as well as field and laboratory testing will be carried out by specialised contractors under guidance of the Consultant. Field test may include: - large direct shear tests - flat jack tests - plate load tests

Seismic Refraction and Geoelectric Survey The performance of seismic refraction survey and geoelectric profiling has the purpose to obtain more knowledge about the ground conditions below the main civil structures and in the reservoir area, the permeability of the river deposits and the required foundation depth for the structures. This information is of importance for design and construction, e.g. seepage control.



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Grouting Tests Grouting tests will be used as important input parameters for the detailed design works and will particularly form the basis for an adequate design of grout curtains for seepage control and grout layers for soil / rock improvement.

Sub-Task 2-3: Additional Hydrological Investigations Following the data review on meteorological and hydrological data and the assessment of the reliability of the available flow records, the Consultant will prepare a programme for additionally required hydrological investigations. Normally additional hydrological field investigations would be carried out by specialized contractors or provided by the Client. However, the results will be reviewed, evaluated and documented by the Consultant.

Sub-Task 2-4: River Sediment Sampling To determining possible sedimentation of the reservoir and to define requirements for special sediment structures like desilting basins etc. sediment sampling of bed load as well as suspended load, during dry and rainy period shall be carried out.

Sub-Task 2-5: Report on Additional Surveys and Investigations At the completion of the field surveys and investigations the Consultant will receive the full information and databases from the contractors. Based on the findings the Consultant will establish a final report, which will contain all records and interpretation of:

Surface investigations and mapping of project area

Auger drilling, core drilling and test pitting operations

Investigations carried out during driving the exploratory adits

Seismic refraction and geoelectric surveys

Grouting tests (if applicable)

In-situ tests, other field tests and laboratory tests.

Task 3: Basic Studies

Sub-Task 3-1: Hydrological and Meteorological Study The establishment of a comprehensive hydrological and meteorological database is a key element for the entire design process of the project. The objective is to develop reliable and up-to-date hydrological data, such as daily and monthly stream flows and flood runoffs for selected events, followed by the estimation of the necessary hydrological project design parameters, like spillway design floods, tailwater rating curves, etc. The major design parameters (e.g. return periods, maximum discharge) to be determined are related to:

River diversion scheme during construction

Spillway structure including energy dissipation structures

Power generating concept (number and size of units, etc.)

Dam freeboard determination.



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All results will be documented in a Hydrological and Meteorological Report.

Sub-Task 3-2: Geological and Geotechnical Study Based on the profound review of all available documents on the local and regional geological conditions (Sub-Task 1-2) and the results and findings of the geotechnical field and laboratory investigations (Sub-Task 2-6) the Consultant prepare the Geological and Geotechnical Report. It will serve as a comprehensive geological and geotechnical data basis for all further design activities and for the preparation of the tender documents. The coverage of the study will be sufficient for the initiation of construction activities. It will also contain conclusions with regard to previous studies that will be either confirmed or their results be rectified.

Sub-Task 3-3: Seismotectonic Study

Generally, if the project is located in a seismically active area a review of all available documents and publications with relation to seismicity will be done in order to assess the seismic hazards of the project. The following main topics will to be covered by the study:

Regional geologic setting

Seismo-tectonic situation

Seismicity of the area with listing of major events

Selection of seismic evaluation parameters (peak ground acceleration, response spectra, maximum design earthquake, operating basis earthquake)

Probabilistic seismic hazard evaluation

Reservoir induced seismicity.

The existing seismic monitoring system of the region will be checked on completeness and efficiency. The results of the investigations will be presented in a Seismotectonic Report.

Sub-Task 3-4: Sedimentation Study The Consultant will assess the future impact of sedimentation on the operation of the reservoir. For that purpose reservoir sedimentation analyses have to be performed. These analyses consider the flow through the reservoir, the minimum and maximum reservoir levels, the reservoir surface area and the reservoir volume at different elevations, and the sediment inflow. The required data for the application of Brune’s trap efficiency curves as a common method for the assessment of the mean annual deposition are:

The annual water inflow volume

The storage capacity of the reservoir

The annual sediment inflow to the reservoir.

For the suspended sediment inflow the corresponding percentages of sand, silt, and clay have to be analysed. In order to perform the Reservoir Sedimentation Study, the Consultant would require the following input data:



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Flow duration curves or mean daily discharges

Sediment rating curves

Percentages of sand, silt, and clay

Reservoir operation data

Elevation - storage and elevation - area curves for the reservoir

Results of available sediment concentration measurements.

Estimates and calculations of relevant data from previous studies will be considered and verified.

Sub-Task 3-5: Landslide Study Instability of slopes can pose serious problems for the safety and operation of a hydropower plant. The Consultant will examine the side slopes of the river in the project area and assess their stability. Of particular importance are in this context the conditions during construction as well as potential instabilities that might be induced by the reservoir impoundment, by floods and/or by water level fluctuations in the future reservoir. The study will identify potential sliding areas, estimate their volumes and divide the sliding zones into different risk categories. Wherever possible, the Consultant will suggest mitigation measures to reduce their risk of occurrence. The Consultant will document the results of his assessment in a Landslide Study comprising a report together with maps and tables.

Task 4: Energy Studies

Sub-Task 4-1: Energy Demand Studies The Consultant will assess the methodologies and assumptions used in the forecast of power and energy in the system and, where appropriate, will revise and up-date the available forecast with current information to produce middle, low and high alternative scenarios. The key parameters for electricity demand forecasting are:

Macro-economy

Demography

Sectorial expansion

Extent of electrification

System losses

Tariff rates

Demand side management

Historic data indicates that electricity sales, inter alia power and energy demands, are highly correlated with national gross domestic produce (GDP) and population. Therefore, it is anticipated that these two parameters shall be the key independent variables in the demand forecasts. The study will also consider isolated demand centres, the potential for increased electrification of rural areas through the expansion of the transmission system, and new industrial developments, which are in the stage of planning.



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The power and energy demand forecasts will consider the particularities of each system in terms of daily and seasonal variations, and any shift that may be occurring to the average system load factor. The demand forecast will also consider high and low growth scenarios. It is anticipated that the alternative high and low scenarios will be developed around pessimistic and optimistic forecasts of the GDP figures.

Sub-Task 4-2: Power Transmission Studies The tasks related to this activity arrangement will include:

Preliminary Line Routing The activities of preliminary line routing will comprise mainly preliminary route alignment marked on maps. A preliminary route alignment will be selected, based on available maps and satellite images. The preliminary alignment includes alternatives to be investigated on site. The site investigations result in a line route description including terrain traversed, the use of land, amount of clearing, special obstacles along the route to be taken into consideration, general conditions of access and construction, comments on special requirements at certain spots, etc.

The line routes of the selected transmission systems will be marked on maps in a suitable scale (1:50,000). Some reference numbers of the angle towers will be shown on the maps as will be the substations and other places of special importance.

Transmission Line

The Consultant will produce a description and recommendation of the design criteria for the line. This includes a review of the previous design criteria for HVAC lines. Modifications due to the electro-technical and construction conditions on site, e.g. height above sea level will be taken into consideration, as well as possible improvements related to overall design. Attention will be given to the details and recommendations in previous studies. The following issues will be included:

- General standards applied, - Conductor size, - Level of insulation, insulator strings, - Span lengths, - Loadings, - Tower type

Furthermore, it is to be noted that tower design, low height and regularity of towers are important issues to be taken into consideration to adapt the line to the landscape and the provision of acceptable visibility.

Substations The technical characteristics and design of the HVAC substations will be established in sufficient detail to provide the basis for the system studies. The major components which will be addressed are:



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- Switchgear, HV-equipment (breakers, disconnectors etc.), busbar arrangement - Transformers - Protection - SCADA - Auxiliary Supply - Civil Works

The principles of the substation design will be presented in:

- Single-line diagrams of the switchgear arrangement, - General layout drawings of the substation.

Sub-Task 4-3: Power System Studies The Consultant will investigate the technical viability of transmission for the various concepts developed for selected generation scenarios and power demand conditions. The network analyses will include:

Load Flow Study

The effectiveness of the various transmission schemes and network topologies will be determined by load flow studies for maximum and minimum load conditions and under normal and emergency operations. The calculations include currents, voltages, real and reactive power flows, taking into account voltage-regulating capability of generators, transformers, specified generation schedules as well as net interchange among interconnected systems.

Short-Circuit Fault Calculations

Short-circuit calculations will be performed to study the system behaviour under fault conditions. For these calculations the maximum generation schedule will be used. The calculated values will be used to establish guidelines and to determine design fault levels for the dimensioning of the electrical equipment, including substation busbars.

The calculated values will be compared with the switchgear ratings to check the compliance with permissible stress-thermic or dynamic criteria. The results will be presented in short circuit diagrams and tables.

Stability Study

Stability analyses will be carried out in support of load flow studies. The stability studies will be performed to determine power transfer capabilities and limits for stable operation of the transmission system following a severe fault or disturbance. The studies will cover the most detrimental system operating points found in the load flow analyses and arrive at the permissible fault clearing times to maintain system stability considering the operating times of relays and circuit breakers.

Task 5: Social and Environmental Studies The aims of the environmental and social impact assessment are to establish the existing environmental and social status of the project areas, examine the environmental and social impacts of the project, and to compare the impacts and marits of the alternatives to assist with final selection of the project site.



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Sub-Task 5-1: Collection of Baseline Environmental Data One of the first tasks is to begin liaison with, and collect data and information from various sources. Simultaneously, and in the light of available data and information from these sources, there will be need to obtain a thorough understanding of project engineering options and project hydrology (from the engineering team) and for first visits to the project area.

Compilation of the baseline data will start with the collection and review of the data and will continue with field surveys and studies. This process will include:

Review of existing data, studies and engineering proposals concerning ecology of the region and water management to mitigate adverse impacts of regulation,

Field visits to project impoundment areas, lower river (excepting transmission line routes at this stage), and first assessment of any major bio-physical environmental constraints,

Making a first estimate of the number, and assessment of socio-economic conditions, of populations within full supply levels of potential reservoir impoundment areas,

Assessment of flood hydrographs of the lower tributaries

Planning and beginning implementation of monitoring and baseline surveys.

Sub-Task 5-2: Environmental and Social Scoping and Screening of Selected Alternatives

The arrangements, layouts and project details will be obtained from the technical studies, together with the details of the areas which would be inundated, or otherwise directly affected by the project alternatives. The existing topographic mapping and aerial photography will be used in conjunction with field visits and surveys, to establish the extent of the potential direct impacts of the alternatives. Preliminary assessments of downstream level/flow requirements will be made during field work. Simulations of reservoir behaviour, turbined flows, spillway releases, and of artificial freshet releases, and records of downstream tributary flow will be taken into account. These investigations should assist understanding of former unregulated conditions, i.e. with and without the hydroelectric project. It is hoped that these investigations will provide information on environmental conditions for known special and normal "bench mark" seasons and years in these periods with which hydrographs at gauging stations may then be correlated. This should lead to defining seasonal "target" ranges of flows which attempt to simulate unregulated conditions to avoid flood damage to settlements and key infrastructure and development areas.

Sub-Task 5-3: Additional Baseline Data Collection Further data, as needed will be collected for which detailed surveys will be conducted in the project impoundment area and areas of associated dam construction works, access road and transmission line routes, and the downstream impact areas according to the scoping findings and comments from the Client. All of the issues are necessarily now unknown but it is certain that attention will be given to obtaining field information by surveys to establish a firmer data base of socio-environmental factors. Survey results will be summarised in the EIA report and significant survey reports themselves will be appended to the EIA.

Sub-Task 5-4: Environmental Impact Assessment (EIA)



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Impacts During the Project Construction Period

Impacts during the project construction period and their mitigation will be described for the whole project area and mitigation and enhancement measures will pay special attention, inter alia, to the following: - Explosives and other hazardous chemicals, - Disposal of excavated material and land reclamation, - Supply of construction materials, - Works to ensure ground safety, - Flood prevention, drainage activities and sediment control, - Activities spreading dust, - Transportation infrastructure, - Electrification plan, - Construction noise and vibration, - Tree clearing, - Agricultural land, - Workforce water supply and waste-water, - Solid wastes, - Risks and dangers to public health and safety and the environment.

Sub-Task 5-5: Environmental Mitigation Plan (EMP)

Monitoring

It will be important that construction and operational impacts of the project, including resettlement impacts, are monitored. Principal issues requiring monitoring will be scheduled.

Mitigation and Monitoring Cost Estimates

Mitigation and monitoring costs, including inter alia compensation, resettlement and institutional costs, will be estimated and summarised for the pre-construction and construction period in terms of capital and annual recurring costs.

Sub-Task 5-6: Social Impact Assessment (SIA) In addition to the aspects studied under the EIA, the following aspects will receive particular attention in the SIA: - The number of households, population and accommodation inundated or directly affected

by the reservoir, - Agricultural land or other productive areas inundated or directly affected by the Project

structures, - Disruption of communication routes. - Changes to fishing opportunities and the potential for commercial fisheries, - Permanent employment opportunities and other long-term sources of income, - Accommodation and infrastructure for construction workers, - Opportunities for employment of local workers.

Impacts of a Large Workforce on Small Local Communities

Compensation, and measures to be taken to resettle and re-establish families and incomes, will be described. Depending on the scale of resettlement, the Resettlement Plan will comprise a chapter in the EIA report.



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Impacts During the Project Operational Period

Impacts and their mitigation during the project operational period will be described principally for the reservoir and downstream area.

Project Area Development Programme

It is expected that the project must be designed to bring tangible benefits to those who live in the project area and are directly affected by it, thereby encouraging in them a sense of participation. In addition to the payment of adequate compensation and the provision of a just resettlement programme to those who lose land, fixed assets and sources of livelihood, it will be necessary for the project to contribute directly to the welfare and development of the area in which it operates and generates power. For this purpose, a development programme (including riparian areas of reservoir if the FSL is raised), to be funded by a portion of the hydropower project revenues from sales of electricity shall be established. Field surveys, including consultations with groups of local residents, will have identified sectors in which improvements are required; these may include, for example, public health, rural electrification, education, potable water supplies, transport and communications, agriculture, horticulture, forestry and possibly special assistance to the poor and disabled.

Sub-Task 5-7: Final Report on Environmental and Social Impact Assessment The Environmental and Social Impact Assessment of the selected project will follow guidelines provided by World Bank's Environmental Assessment Sourcebooks. These require an EIA report which is a stand-alone and authoritative document. The chapter and sub-section contents of the EIA report will be established at the beginning and responsibilities allocated to consultants individually and jointly. The EIA report may include the following:

Introduction - Project background, project description, approach and methodology,

Policy, Legal and Administrative Framework,

Environmental and Social Characteristics of the Project Area,

Impacts during Construction (including inundation) Period and Mitigation:

Impacts during Operational Period and Mitigation:

Analysis of Alternatives,

Development Programme,

Public Information and Participation,

Monitoring,

Institutions for Implementing Mitigation, Monitoring and Participation,

Environmental Management and Resettlement Plan,

Mitigation Cost Estimates,

Risks and Uncertainties,

Summary and Conclusions. The EIA report will be supported by references, photographs, reports on field surveys, schedules of agencies/persons consulted, and other documents.

Task 6: Conceptual Design Study



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Sub-Task 6-1: Definition of Project Options

Dam Based on the available information from former studies and information obtained during first site visits the Consultant will evaluate various dam sites and different dam types, mainly with regard to topographical and geological conditions. Initial site appraisal visits carried out in the inception phase will also look into the aspect of availability of sufficient quantities of concrete aggregates and other construction materials in the project area.

Intake, Desilting Structures and Tunnel Alignments

The location and concept of the intake and desilting structures, if required, will be studied. Criteria to be applied for the alignment of the tunnel in zones of low overburden (e.g. in the vicinity of the side valleys) may be affected by the steep rock slopes of the area. Rules of thumb for minimum overburden will be adopted to the conditions along the different tunnel alignments on the basis of geological and geotechnical considerations during the first site appraisal. They will determine the tunnel alignment at critical locations, which include lateral valleys and surge tank areas, and will minimise lining costs, especially those of reinforced concrete and steel lining. For the purpose of planning, it will be important to establish the probable method of excavation (e.g. TBM or by conventional drilling and blasting), the temporary support measures, the rates of progress and total specific cost per m of tunnelling.

Power House Different arrangements of the power house, such as open air power house on the river bank or underground power house shall be also taken into consideration. The final selection of the power house arrangement will depend on the specific topographical and morphological conditions of the selected site. The optimum installed capacity will be determined by economic criteria. The installed capacity will be defined by the "incremental energy cost"; i.e. the incremental generation cost should not exceed the generation cost by an alternative thermal plant.

Access Roads and Infrastructural Requirements For the purpose of the Conceptual Design, appropriate alignments for permanent access roads will be selected for the entire project. Possible road routes will be inspected during field reconnaissance, being subject to successive improvement. Other infrastructural requirements will be estimated within the scope of the conceptual study, as may be necessary. These could include a central administration and workshop buildings for the entire project, as well as houses for the operational and administrative personnel.

Sub-Task 6-2: Preliminary Cost Estimates For the optimisation and selection procedures of the Conceptual Design Study a realistic assessment of construction costs will be required. It will therefore be essential that a cost estimate is prepared initially during the Conceptual Design Study which is consistent with the basic project assumptions. The costs will be distinguished in investment costs and running costs. The investment costs include civil construction costs and the capital cost of permanent mechanical and electrical equipment. Running costs of the project include operation and



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maintenance costs and replacement costs. In addition to the basic cost estimates, allowances for physical contingencies will be estimated. For a project with a certain number of development options it is important to assess the economics of the various options on a Net Present Value (NPV) basis. This allows to compare the relative merits of the options with respect to different costs, timings and benefits. For the purpose of optimisation of major project components or lumped project components (e.g. active storage capacities), cost functions will be established, as for example:

cost of storage versus active storage capacity; or, for the dam options: cost of dam height (reservoir level) versus active storage capacity;

cost of tunnels versus tunnel diameter;

cost of unit installed capacity versus its capacity rating. The investment and running costs determined from the above methodology will be used as the basis for establishment of expenditure cashflow schedules. These schedules will be used in the cost-benefit analysis and comparison of the merits of the project options considered.

Sub-Task 6-4: Preliminary Economic Assessment Based on the preliminary cost estimates and the NPV of the project options under consideration, a Preliminary Economic Analysis will be carried out. This will be a useful guide to the economic performance of the project options, and will be available at an early stage of the study. The final economic and financial analysis will be carried out under the DPR by full conventional cost-benefit analysis, once the technical and economic parameters for the selected project option have been established in more detail.

Sub-Task 6-5: Selection of Best Suited Scheme In order to identify the best suited project option, a screening of all project options will be carried out. This screening will be based on the calculated net present value (NPV) of each project alternative. These alternatives will be documented in a project catalogue, and a ranking list will be established which will expose, besides the economic merits of the alternatives, an evaluation of other factors such as environmental and socio-economic aspects, and social acceptance by the people living in the project area will be carried out which may probably constitute knock-out criteria for some project alternatives. These economic and non-economic pros and contras will be transformed into a project matrix, commented and valuated, and a firm recommendation will be given by the Consultant for final selection of the best suited scheme, which will be taken forward into the subsequent DPR stage.

Sub-Task 6-6: Alternative/Comparative Studies of Project Components A large potential for technical improvements and construction cost savings as well as for raising the project's economical performance is considered to lie in the following fields:

Optimisation of the locations of all structures with regard to topographical and underground conditions (e.g. final definition of dam axis);

Definition of the best waterway alignment, in particular (diversion) tunnel sections, with regard to the results of the geotechnical investigations;

Detailed assessments to find the best-suited power house/tailrace concept with regard to location, power house type (cavern/surface), and type of tailrace waterway;



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Definition of the best-suited operation concept of the scheme and, interrelated with this task, optimisation of the total installed capacity and definition of the optimum number of generating units.

The Consultant will carry out alternative/ comparative studies of the major components of the project, taking into account geological, geo-technical conditions and seismicity.

Sub-Task 6-7: Drawings All project components of the selected alternative will be presented as conceptional drawings on feasibility level, showing the general arrangement and main dimensions of the structures to allow quantity estimations for preliminary cost estimates. This include, inter alia:

General project layout

Layout of each major structure

Longitudinal sections of all waterways

Sufficient cross sections and details to establish the magnitude and the characteristics of the works

Task 7: Feasibility Study Report (FSR)

Sub-Task 7-1: Draft Feasibility Study Report On completion of the Conceptual Design the Consultant will present a Draft Feasibility Study Report which will incorporate all of the information and results of the preceding studies (i.e. Energy Studies, Assessment and Definition of Project Options, Preliminary Cost Estimate) and will gather as much as possible informations and results of ongoing studies, such as Hydrological and Meteorological Studies, and the geotechnical field investigations. The FSR will also include an Executive Summary. The FSR will constitute a “bankable” document. It will therefor also include other information required by funding agencies, which are likely to be approached for funding of the project.

Sub-Task 7-2: Final Feasibility Study Report In reasonable time after the submission of the Draft Feasibility Study Report the Consultant shall submit the Final Feasibility Report incorporating comments of the Client and related authorities/agencies.

Task 8: Detailed Studies and Calculations

Sub-Task 8-1: Reservoir Simulations The main objectives of reservoir simulations are: - To determine the mode of operation of the reservoir yielding the maximum energy, - To determine the firm and secondary energy yields and load factor, - To consider the impact of installing a flood warning system and of environmental releases

on the energy yields, and - To assess the requirements for the provision of additional spillway discharge capacity.



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The results of the reservoir simulations, in terms of firm energy, secondary energy and dependable capacity will be used in the economic analysis to evaluate the economic performance of the project.

Sub-Task 8-2: Hydraulic Calculations and Definition of Hydraulic Model Test Requirements Hydraulic calculations will be carried out for the spillway, diversion tunnels (if any) and bottom outlet, transient flow the power waterways, and the outlet works on each part of the Project.

Hydraulic Calculations

For each scheme part of the Project, the Consultant will determine all the hydraulic parameters for the feasibility level design. These include: - Water levels at the river diversion inlet structure, - Water levels at the river diversion outlet structure, - Discharge capacity of the diversions tunnels, - Discharge capacity of the spillway structures, - Water levels at the plunge pool, - Tailwater rating curves. For the spillway structures, the Consultant will perform hydraulic calculations for the following aspects: - Flood routing in the reservoir, - Assessment of head losses in the approach channel, - Discharge capacity of the weir structure for free overfall flow, - Discharge capacity of the weir structure for gate controlled orifice flow, - General flow condition upstream of the weir structure and in the chute, - Sufficient freeboard on the chute side walls considering aeration of the flow and

supercritical flow phenomena, as e.g. shock waves, - Prevention of cavitation erosion, - Pressures and forces acting the weir structure, chute and flip bucket, if any, - Scouring process in the plunge pool. For the power waterways the following hydraulic calculations will be undertaken: - Submergence of the power intake, - Linear and local head losses in power waterways.

Definition of Hydraulic Model Tests

Hydraulic modelling will aim to optimise the shape and dimensions of hydraulic structures, such as intake, power waterways, spillway, bottom outlet etc. The Consultant will prepare specifications for the hydraulic model tests to be performed during the detailed construction design stage of the project.

Sub-Task 8-3: Definition of Installed Capacities and Unit Sizes Preliminary sizing of the installed capacity of the project will have been undertaken in the conceptual design, based on the market load factor requirements established in the power demand study, and the results of the reservoir simulations.



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The selection of the number of units will take into account any requirements for phasing to meet the load demands, flexibility of operation and cost. Consideration will also be given to transportation and handling of the units in determining the appropriate size and number of units.

Sub-Task 8-4: Assessment of Seismic Activities and Seismic Design Loads The seismic risk for the project alternatives will be evaluated in accordance with the latest recommendations of the International Commission on Large Dams (ICOLD). This guideline defines three different earthquakes for which a dam and its appurtenant structures should be designed:

The Maximum Credible Earthquake (MCE) which is the largest reasonably conceivable earthquake that appears possible along a recognised fault or within a geographically defined tectonic province. The MCE may result in severe damages to structures.

The Maximum Design Earthquake (MDE) which will produce the maximum level of ground motion for which the dam should be designed or analysed.

The Operating Basis Earthquake (OBE) represents the level of ground motion at the dam site for which only minor damage is acceptable.

For the reference earthquakes (MDE and OBE), the peak ground acceleration (PGA) at bedrock level are inferred from the attenuation laws which relate peak ground motion parameters to distance from the source of energy release (focus) and to magnitude. The applicability of the attenuation laws has first to be checked with available local strong motion data which may be available at the project area.

The seismic hazard analysis will be undertaken to determine the ground motion design parameters for the project site. The seismic hazard will be defined using both deterministic (MDE) and probabilistic (OBE) evaluation procedures. The seismic data will be used to establish pseudo-static load factors and structure/foundation interaction dynamic parameters, which shall be incorporated into the stability and structural calculations of the dam, tunnel portals and appurtenant structures in addition to high excavated rock slopes.

Attention shall also be given to the question of Reservoir Induced Seismicity (RIS).

Sub-Task 8-5: Structural Calculations and Stability Analysis The structural calculations will be performed to approved modern standards, with design loads being defined in accordance with international norms. The structures will be designed to withstand not only normal static and dynamic loads but also transient loading conditions which could arise during construction, subsequent testing or maintenance work. Cases of wrong operation or the malfunction of project components and their equipment will be addressed to, as well as seismic loading. The required stability analyses for the tender design stage as described hereunder are mainly those for the dams and the underground structures as well as for the cut slopes. For appurtenant structures of minor importance, standard procedures for stability calculations will be applied. Preliminary stability and structural calculations for the concrete structures will be performed to determine dimensions and the amount of reinforcement as realistic as possible, applying internationally recognised standards.



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Detailed and final stability and structural calculations will have to be performed either by the contractor or consultant during the construction stage, prior to preparation of the construction drawings. On the basis of sound engineering judgement the overall dam stability will be examined for all the different loading cases, which can occur during the dam's life. The stability criteria used will correspond to internationally well proven methods in accordance with the recommendations of the International Commission on Large Dams (ICOLD).

Power House (applicable to cavern power house type) Detailed elasto-plastic finite element analyses and wedge stability calculations will be required for cavern power houses and their appurtenances. To determine the distribution of stresses and deformations in the area surrounding the caverns, elasto-plastic stability analyses will be carried out for typical cross sections through the power cavern complex. The results of these calculations serve as a basis for the determination of the support measures for typical cross sections.

Power Conduits/Waterways Finite element analyses and wedge failure analyses are required for all parts of the waterway system. Basically, stability analyses for the waterways will assess elastic and plastic deformations and plastified areas around the tunnels. Plastic deformations and plastified zones occurring when the rock strength is exceeded will be calculated for different rock classes and different heights of overburden. Thus, the temporary rock support including the rock loads acting on the permanent lining can be established.

Cut Slopes The Consultant will analyse the main cut slopes to be excavated in the site area and its vicinity with regard to their expected slope stability. Main cut slopes are considered to be the slopes above all tunnel entrances, at site access roads and the slopes that will be exposed during the foundation excavation of the dam. Thus, suitable protection measures such as rockbolts, wire mesh and shotcrete, nets or reduction of slope gradients can be defined.

Stability Assessment of the Reservoir Most important in this regard is the safety assessment of the slopes of the future reservoir. Sliding planes in rock or moraine deposits will be assessed with regard to their stability during initial impounding, reservoir operation and during seismic activities. It will be assessed, which maximum water level changes are permissible in order to ensure the stability of the slopes.

Sub-Task 8-6: Emergency Preparedness Action Plan The Consultant may establish an "Emergency Preparedness Action Plan" which would deal with the following aspects:

Hydrographic observation and flood warning schemes

Drawdown and flood control operation of the reservoir

Emergency emptying of the reservoir

Inundation maps for flows up to the design flood, and for catastrophic conditions caused by dam failure

Evacuation of flood-threatened areas

Environmental accidents

Rescue operations and other emergency provisions, as well as definition of responsibility



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Equipment, material and support available for emergency relief

Coordination of emergency relief actions with third parties (civil defence, police, hospitals etc.)

Emergency operation of power plant, gates etc. associated with the dam

Emergency warning system

Emergency decision-making process and procedures Planning of emergency actions may be done for several types and modes of emergency including the analysis of the most severe possibility: that is the failure of the dam. The plan will cope with emergency precautions and possible emergency repair measures at the site and with warning and emergency relief action downstream of the dam. Consideration will be given to the extend of inundation, the development and occupation of the land that would be flooded, and the time available for emergency action.

Task 9: Detailed Design

Sub-Task 9-1: Definition of Design Criteria In this sub-task all design criteria will be established and documented during the initial period of the tender design. This would include criteria resulting from the geotechnical investigations, assessments of seismic risk, hydrologic and sediment investigations, etc. The design criteria memorandum will set out the criteria and methodology to be adopted, broadly to cover the following fields:

Civil Works - Geotechnical parameters for stability and stress calculations - Special soil mechanics analysis methods - Structural design methodologies - Load cases for normal, unusual and extreme loads - Safety factors corresponding to the above load cases - Concrete and reinforcement parameters - Hydraulic design parameters and calculation methods - Requirements from the investigations by hydraulic model tests - Drainage requirements and standards, filter criteria - Seepage criteria including critical exit gradients - Design flood criteria - Freeboard criteria - Criteria for river diversion and river closure - Operation criteria - Access guidelines - Architectural features - Aspects of installation of mechanical and electrical equipment

Mechanical Works and Electrical Works including Power Transmission

- Operation criteria of plant and hydro-mechanical equipment - Rating of equipment - Power factor - Setting of turbine axis - Runaway speed - Setting of draft tube soffit - Aspects of installation - Aspects of commissioning



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- Security and safety requirements - Reliability and availability - Material types and standards - Design methodologies and load cases - Transient time constants - Enclose type, isolation levels - Cooling methods and temperature rise - Voltage and frequency limits - Permissible loads - Criteria on control and protection - Criteria on communications and monitoring - Criteria on emergency and standby equipment - Construction and maintenance requirements - Service design conditions of transmission line - System parameters of transmission - Rated voltage and insulation withstand voltages - Normal and short time current ratings

Control and Monitoring

- Extent of the supervisory, control metering and alarm requirements - Frequency and accuracy of data to be collected - Amount of data storage - Speed of response of the system - Security of the system including telecommunication methods and alternatives - Presentation of data and extent of data processing at the control centers - Expandability and flexibility of the system to cater for later modification if necessary

Sub-Task 9-2: Design of Dam and Appurtenant Structures The design of the dam and appurtenant structures (river diversion works, spillway, bottom outlets, if any) will provide all information on the proposed type and dimensions of structures with clear explanations as to the technical reasons for the designs proposed. The main objective of the feasibility design is to propose least cost facilities and, on the other hand, reliable structures in consideration of the respective design criteria as defined during the Sub-Task 6.1.

Dam (exemplarily for an RCC Dam)

The following features shall be studied in the design of a concrete gravity dam, either conventionally built or using roller compacted concrete (RCC): - Load bearing capacity and jointing of the foundation rock, particularly with regard to

grouting and drainage. - The stability against sliding and overturning - Earthquake loads - Stress distribution at the concrete/rock interface and at any level within the concrete

structure or the foundation, as required - Galleries for grouting and drainage purposes The final height of the dam will be optimised in close relation with the precise definition of the FSL, taking into account the reservoir operation studies and the upstream limits associated with the maximum tailwater level and with the maximum water level in the reservoir, taking into account the least cost alternative for the gated spillway.



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Seepage through the foundation and abutments, and leakage through the reservoir rim will be studied. These studies will be performed using conventional analyses and knowledge of geotechnical conditions of the foundations. The results will be used to formulate adequate foundation treatment for seepage cutoff, such as grouting and drainage curtains. The design of the dam will be based on the materials available for concrete or RCC. Earlier identification of the aggregate (size grading, physico-chemical characteristics) and cementitious material (cement, fly ash, natural pozzolan) available will have enabled the definition of the main sources to be use for each component of the Project. The tender design will use the results of the laboratory studies, performed on representative tests samples, with the selected materials for the study, enabling determination of the composition and characteristics of the concrete and RCC including: - Unconfined compression strength, - Tensile strength, - Elasticity modulus, - Setting time, - Exothermal reactions, - Alkali aggregate reactions.

Spillway

The spillway of the project will be designed according to the recommendations of ICOLD. Alternative spillway concepts will be considered (e.g. re-using of the river diversion tunnel) in order to develop a final design which will incorporate optimum hydraulic and structural characteristics and also represent an economical layout of project components. Geotechnical factors, such as foundation conditions, erosion in the waterway downstream, regional seismicity, and hydraulic factors such as air entrainment and sediment transport, which will affect the concrete surfaces of hydraulic structures, will be considered in the alternative spillway layouts.

River Diversion During Construction Construction planning for a concrete gravity dam would be essential in order to determine whether the river can be diverted through a gap between blocks of the dam. Should a tunnel prove to be necessary or in case of an embankment dam, a risk analysis will serve to optimise the height of the cofferdam and the tunnel diameter. Consideration would be given to whether the diversion tunnel should be plugged during the last dry season of dam construction or whether the tunnel should be equipped with bottom outlet gates incorporated into a concrete plug, for utilization during controlled filling of the reservoir.

Outlet Structures A bottom outlet or middle outlet (for concrete dams) serve for a variety of puposes including emergency drawdown, release of water in case of power plant shutdown, sediment flushing, and releasing a portion of the spillway discharge. Layouts for the outlet works will be consistent with the other project features and conform to the site geotechnical and topographic characteristics.



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Sub-Task 9-3: Design of Power Intake, Desilting Chambers and Waterways

Power Intakes

Power intakes will be located as close as possible to the power house to optimise hydraulic conditions for power generation. They can be separate from the dam or integrated in the dam structure (concrete dam). Power intakes will be designed taking account of the following: - Head loss as small as possible, - High water velocities in the vicinity of the intake structure and in the rack section will be

avoided, - Provisions for later addition of pressure tunnels, - Water quality considerations, - Intakes must pass the maximum power draught over the full range of operating levels

without risk of air entrainment, - Measures to prevent the ingress of trash and debris.

Desilting Structures

In case of sediment loaded rivers in order to reduce the erosion of the guide vanes and runners of the Francis turbines desilting structures are required adjacent to the intake structure. For design of desilting basins or chambers the following criteria have to considered: - Concentration and particle size distribution - Decision on critical sediment grain size, i.e. the grain size to be removed to 90 % or more - Cross section of basin / chamber - Entrance of flow - Deposition of sediments - Flushing or sluicing of deposits

Waterways

A review of all geological factors relevant to the design of the waterways will be undertaken using final results from the geotechnical investigations carried out at the tunnel portal, outlet and access points. Whereas the horizontal alignment of the scheme was defined in the conceptional design, final definition of the vertical alignment will depend on the field investigation results and assessment of overburden criteria. Stability calculations will be undertaken with the aim of estimating the performance of the rock mass during excavation, assuming a range of parameters for the rock mass moduli, the angle of internal friction and the relation between horizontal and vertical stresses at the depth of the tunnel. Temporary support using anchors and shotcrete will be designed on the basis of stress-strain calculations of the rock section around the tunnel. The calculations will consider possible stratification of the rockmass and the proximity to the surface, where necessary. Support classes will be developed for different types of rockmass. For feasibility level assessment three rock classes and three or four support classes will be developed. The tunnel support applied to the rock classification over the tunnel length will be used for cost estimation.



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Lining procedures in the high pressure waterways will be developed to avoid interference with excavation and installations at the power house. The optimum size and number of the waterways (headrace tunnels, penstocks, tailrace tunnels) will be determined taking into account the surface roughness (affected by construction method) and the lining requirements. It will depend, among other factors, on the estimated roughness which will be affected by the method of construction in parts where lining could be avoided, the need for lining and reinforcement in most of parts of the waterways, eventually the use of steel lining when necessary. The manifold system will be configured to minimise the hydraulic head losses, and the losses will be calculated for a range of power draughts. The tailrace system operates under low pressure compared with the headrace system. Lining requirements are less severe than for the headrace system; blasting and shotcrete lining are a likely option. The tailrace outlet will be designed with bulkhead panels to close against the maximum water level expected in the river downstream.

Surge Tank

If it is necessary to design waterways with upstream and/or downstream surge tanks, transient flow studies will be performed with the aim of fixing the surge tank design. This should provide a stable hydraulic system and protect the power waterways and power station against the pressure effects when a load rejection occurs or when the turbine starts working at the most unfavourable time.

Sub-Task 9-4: Design of Power House Definition of civil work structures will be undertaken in co-ordination with electrical and mechanical studies, so as to optimise the general arrangement taking full account of the plant and operation requirements. Special attention will be given to the ease of access for construction and operation and maintenance. The final arrangement of the power house will be determined based on estimates of the optimum installed capacity and number of units, type of power house (underground or at the river bank), geological and geotechnical considerations, and access requirements. The optimum locations for the transformer banks and switchyard will be selected based on evaluation of geotechnical conditions. The analyses will mainly be concerned with the following issues: - Size optimisation of power stations and transformer houses, in connection with

Electromechanical aspects, - Optimisation of main structures, such as dimensions and levels of machine hall,

associated service areas, control room, electrical equipment rooms, - Size optimisation of surge tank, if any, - Diameter and number of headrace tunnels, penstocks and tailrace tunnels - Thickness of steel and concrete linings, - Permanent and temporary access, connecting galleries, if any, - Intake structures, - Tailrace outlet structures, - Protection against flood.



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These studies will take into consideration the geological and topographical conditions, the schedule aspects and the cost aspects.

Underground Power House Should an underground power house be considered, the following consideration shall be applied: - The horizontal location of the power house cavern and the direction of its main axis are

determined from evaluation of the geological and rock mechanics conditions, - The design of the underground power station will be determined by the physical condition

of the rockmass (jointed, unjointed), the joint pattern, estimated strength parameters and the primary state of stress,

- The design concepts will allow construction of the power house cavern without a massive concrete support arch. Stabilization and consolidation of the rockmass around the cavern and redistribution of the forces relieved by the excavation can be achieved with prestressed anchors, rock bolts and the application of shotcrete reinforced with steel mesh.

- Final lining of the cavern will include rock bolts and shotcrete reinforced with steel fabric. The amount of support (grid of bolts) will also depend on the results of the finite element calculation and on a general assessment of rock quality.

- The width of the power house cavern and the spacing of the units are governed by the size of the turbines and their upstream shut-off valves, the size of the generators and the space required for auxiliary electrical and mechanical equipment. The total length of the cavern results from the number of units and the length of the erection bay and the end blocks. The height of the cavern is determined by the combined heights of the turbine, the generator and the required clearance to the power house crane. The elevation of the cavern is determined by the setting of the turbine runner axes.

Sub-Task 9-5: Design and Performance Specifications of Hydro-Mechanical Equipment

The purpose of the design of hydro-mechanical equipment is to firm up the choice of gate type, operating systems, operation principles, dimensions and masses to obtain the equipment cost. For hydro-mechanical equipments, an outline design will be prepared which then will be integrated into the drawings of the civil design. Within the outline design, the equipment proposed will be specified. The Consultant will design the dam and waterway hydro-mechanical equipment taking into consideration the operation of units and gates, safety of dam, power plant and personnel, and maintenance of hydro-mechanical and electro-mechanical equipment.

Gates

The type, number and dimensions of gates will be determined taking into account the flow to be discharged, the topographical and civil works constraints (e.g. the hydraulic forces transmitted to the civil works), and the erection, operation, safety and maintenance requirements. The estimation of the mass and the forces to be created by the opening and closing element will be calculated. Common standards for gate design will be used and gates will be specified to the following extent: - Type and dimensions of the gate,



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- Differential pressure for design, - Type of hoist equipment, - Equipment at the dam, - Type and arrangement of seals, bearings, servomotors, etc. All major systems of standardized mechanical equipment will be specified and their costs estimated. Gates to be installed may include: - Radial gates for the spillway, - Bottom outlet gates and mid-level gates, - Temporary closure gates for the diversion tunnel, if a diversion tunnel is required, - Bulkhead gates and emergency roller gates at the intake, - Bulkhead gates at the tailrace outlet.

Stoplogs

The dimensions of each element will be determined either for interchange ability of elements (resulting in large dimensioning for top elements) or total minimum weight (imposing a fixed stacking order).

Trash Racks

The trashrack bars will be dimensioned to support the static forces due to partial clogging and the passage of the trash rack rake carriage. The spacing between main panels and crossbars will be calculated taking into account the foreseeable sizing of floating debris.

Steel Penstocks

Steel penstocks and liners will be dimensioned according to internal dynamic loads issued from hydraulic transient calculations, external pressures for the underground penstocks issued from the available hydrogeological data of the surrounding rock, climatic conditions for outdoor penstocks, and various operating scenarios: permanent, temporary and accidental. The design will specify the length of different internal diameters and plate thickness along the pressure shaft and the adjacent manifold system.

Sub-Task 9-6: Dimensioning and Performance Specifications of Electrical Equipment

The Consultant will establish the dimensions, the technical description and the performance specifications of the complete power plant equipment: - Turbines and main inlet valves, - Mechanical auxiliaries, - Generators, switchgear and transformers, - Electrical auxiliaries, including power cables and electric cubicles, and, - Monitoring, protection and control of the plant. Description of equipment and performance specifications will be adequate for obtaining an adequate accuracy of energy generated and a preliminary but reliable price quotation.

Turbines and Valves



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The operating ranges of the turbine will be determined according to limits set up on the discharge and the power versus the net head. This optimisation will be carried out in co-ordination with the optimisation of the generator. The main parameters of turbines and valves will be determined by means of a sizing numerical tool based on statistical data available from the Consultant’s data base of international turbines under operation. The dimensions of turbines will be up-dated values, taking into account the selection of turbine specific speed. The required elevation setting of the turbine will be determined taking into account the steady state conditions as a consequence of the selected specific speed, and the overall optimisation of the civil works including access and the downstream surge shaft, if any. Aspects to be considered in the design are: - Design and arrangement of shafts, especially the coupling with the generator, - Design of turbine outlet, in particular the outlet channel and the tailwater depression

system, - Requirements for easy maintenance work on turbine runners and other worn parts.

Mechanical Auxiliaries

The following various mechanical auxiliaries, either for the units or for the power plant will be described in terms of functional specifications and main components, in order to match with the environmental and civil works constraints: - Main unit water cooling, - Drainage and dewatering, - Firefighting and service water, - Handling (cranes, lifts), - Ventilation and air conditioning.

Generators, Switchgear and Transformers

Design will start with determination of the basic parameters of the electrical equipment, in close coordination with the civil and the mechanical designs. In determining the basic parameters, consideration will be given to the main characteristics of the generators such as rated output, overload capability, power factor and voltage. The generator voltage optimisation will be carried out versus maximum output power, power factor, insulation characteristic, up-to-date technology and manufacturing features. The inertia of rotating parts of the generator set will be determined taking into account the selected speed and electrical performances of the generators, the waterways and turbines hydraulic transients, the performances in terms of frequency regulation, and the technical feasibility of the generator rotor.

Electrical Auxiliaries

Electrical auxiliaries will be described in terms of functional specifications and main components and may comprise following components: - Station service transformers, - Diesel generating units, - AC auxiliary supply,



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- DC supply, - Power cables, - Earthing system, - Fire alarm, - Water level measurement. A general single line diagram will be designed taking into consideration the main units, the medium voltage equipment, the electrical auxiliaries distribution and the power plant switchyard.

Monitoring, Protection and Control of the Plant

The protective relaying is designed in order to effectively detect electrical and mechanical faults and alarm, disconnect or shutdown the faulted apparatus, as necessary, and to provide for personnel safety and equipment protection. The overall architecture of the computer-based control and monitoring will be designed taking into consideration: - The main units and their auxiliaries, - The electrical and mechanical auxiliaries, - The waterways and dam hydromechanical equipment, - And the power plant switchyard. The functional definition of the supervisory, control and data acquisition system includes the functional exchange with the dispatching through operators, and deals with functional aspects based on a hierarchical approach as described in international standards.

Sub-Task 9-7: Transmission Line from Power House to Substation

Power Station Switchyard

The following aspects will be defined for the power station switchyard: - Location, - General layout, - Single line diagram, - Electric characteristics such as short-circuit current, rated power and voltage of

transformers, rated currents, BIL, protection system, metering and monitoring circuits (typical diagrams).

Should an underground power house be considered, it is likely that the switchgear will be gas-insulated and located in the transformer cavern. From there, high voltage transmission lines would be installed in a cable tunnel or shaft leading to a surface terminal to enable the output to be fed to the main substation. All electrical equipment would be controlled from a control room in the main power house cavern, but with connection to the administration building near the power plant.

Transmission Lines

For the transmission lines the following aspects will be defined: - Routing of the transmission line on the 1:10,000 maps and if necessary, of site visits to

specific areas, - Optimum voltage taking account of the Client’s standards,



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- Characteristics of cables, - Number of circuits, - Losses, - Type of supports. Routing of the line will be determined according to the best compromise between the following main criteria: - Minimise the total length and the number of angles in order to avoid heavy and costly

tower structures, - Minimise the environmental impact, by avoiding the crossing of heavy forests, important

vegetation, plantations, villages and historical monuments, if any, and reducing the negative visual impact of the line,

- Facilitate access for construction and maintenance, by following the existing roads as far as possible so that easy access is available to the line under all climatic conditions.

Sub-Task 9-8: Design of Instrumentation and Control, Telecommunication and SCADA System

The design of the instrumentation, control, telecommunication and SCADA systems requires close co-operation with the Client who will have to specify the specific needs with respect to the required degree of automation and future structure and organisation of plant operation and maintenance. The system will be designed to effectively detect electrical and mechanical faults and alarm, disconnect or shutdown the faulted apparatus, as necessary, and to provide for personnel safety and equipment protection. The overall architecture of the computer-based control and monitoring will be designed taking into consideration:

Main units and their auxiliaries,

Electrical and mechanical auxiliaries,

Waterways and dam's hydraulic steel structures,

Power plant switchyard.

All instrumentation, control, telecommunication and SCADA system components will be connected to self-actuating battery and diesel-electric emergency power supplies in order to maintain the essential functions of these equipment (emergency actuations, data backup, telecommunication etc.)

Task 10: Quantity and Cost Estimation

Sub-Task 10-1: Quantity Estimation Quantities for the main work items will be taken off the tender drawings. A spread sheet will be developed from these quantities to enable the unit rates to be applied, in order to derive the construction costs. Where appropriate, quantities for temporary works will be estimated to enable the construction schedule to be established and the contractor's general costs and overheads to be priced. Typical items in a Bill of Quantities for civil construction works for which the unit prices will be estimated include:



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- For foundation excavation: clearing and grubbing, overburden excavation, rock excavation, backfill, care of water,

- For underground works: excavation through earth and rock according to respective classification, rock bolts and anchors, grouting, gunite/shotcrete, steel arches and lagging, concrete and concrete lining, care of water,

- For foundation treatment: overburden excavation, dental excavation, slush grouting, dental concrete, guniting, borings for curtain grouting including pressure testing and the supply and injection of grout material, borings for drains including fittings, care of water,

- For structures and components: various classes of concrete, cement, reinforcing, shutters, embedded parts,

- For roads: clearing and grubbing, overburden excavation, rock excavation, embankment, pavement, drainage structures, care of water,

- For site preparation: clearing and grubbing, overburden excavation, embankment, care of water,

- For site installation: mobilisation, installation, operation and maintenance, dismantling and demobilisation.

Sub-Task 10-2: Construction and Operation Costs The Consultant will prepare an overall construction programme, including the pre-construction works of the project. The construction schedule will be built up according to the structural components of the project and the main work items to be carried out for their construction; e.g. for the steel lined pressure shaft: excavation and support, installation of steel lining, backfill and grouting.

Civil Costs

From the drawings, quantities will be taken by conventional and computerised methods. In taking the quantities, a pre-established lists of quantities will be used as a guide. However, for the establishment of the cost estimate, the quantities of temporary works must also be taken into account. These will enter into the development of the unit prices to be calculated for the list of quantities. For quantities to be taken from natural materials in the project area, quantities will be given for bulk volumes and for waste material. Typical items for civil construction works for which the unit prices will be estimated include: - preparation and pre-construction costs,# - foundation excavation: clearing and grubbing, overburden excavation, rock excavation,

backfill, care of water, - underground works: excavation through earth and rock according to respective

classification, rock bolts and anchors, grouting, gunite/shotcrete, steel arches and lagging, concrete and concrete lining, care of water,

- foundation treatment: overburden excavation, dental excavation, slush grouting, dental concrete, guniting, borings for curtain grouting including pressure testing and the supply of injection of grout material, borings for drains including fittings, care of water,

- structures and components: various classes of concrete, cement, reinforcing, shutters, embedded parts,

- roads: clearing and grubbing, overburden excavation, rock excavation, embankment pavement, drainage structures, care of water,

- site preparation: clearing and grubbing, overburden excavation, embankment, care of water,

- site installation: mobilisation, installation, operation and maintenance, dismantling and demobilisation.



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From the estimation of quantities and the type of construction to be performed, a construction methodology will be chosen in close cooperation with the project engineering. This will form the basis for selection of construction equipment and productivity rates, labour requirements and the other resources required to build up unit rates from first principles.

Approach to Cost Determination

The approach to estimating the cost of civil construction will be based on an assessment of the scope of the construction operations for which a construction programme will be prepared. The estimates of construction equipment and labour resources required to construct the works will be based on production rates likely to be achieved. The availability of local and imported materials will be taken into account. The total construction cost of each project component will be broken down into: - primary costs which include actual production items, - site establishment costs which include site installation and running costs, - contractor’s other costs which include amounts for insurances, risk and profit, etc.

Electrical and Mechanical Equipment Costs

The cost estimate for the hydro-mechanical, electrical and mechanical equipment will be based on recent quotations on the international market from manufacturers or suppliers of this type of equipment. Items will be priced with reference to similar work elsewhere and taking into account estimated prices for major parts and equipment obtained from manufacturers or suppliers. The cost of such items will be broken down into manufacture (fob), transport to site, insurance, storage, erection and installation and will also consider appropriate spare parts. Any site establishment or on-costs expected to be incurred by the mechanical/electrical contractors will be included in either the equipment cost or the cost of civil works.

HV Transmission

As with the electrical and mechanical equipment, preliminary cost quotations will be obtained from suppliers for major plant elements at the substations. Prices will be obtained for towers, conductors, insulators, PLC, SCADA and auxiliary equipment. Qualities will be estimated for two major work elements including foundations, tower steelwork, insulators, conductors, control buildings, security fencing and access roads. Unit rates will be established from first principles, as for the civil works, in order to estimate the cost of those items. For the major equipment items the costs of supply, transport, insurance, storage, erection and installation will be identified, and allowance will be made for an appropriate spares inventory.

Operation and Maintenance

The cost of operation and maintenance will be estimated based on experience of operating similar schemes in comparable circumstances elsewhere in the world, and adjusted to take account of price levels and conditions in the Project area. This will include, inter alia: - Staff cost (based on appropriate staff organisation in accordance to the requirements) - Annual running cost (spares, consumables, servicing and other regular items for the



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maintenance and servicing) - Administration, accounting costs and insurance - Routine inspection, monitoring, rehabilitation and other engineering costs - Cost of rentals, annual licences and royalties Provision will be included for the removal and replacement of major items of equipment based on their life expectancy under the expected operating conditions.

Sub-Task 10-3: Environmental and Social Mitigation Costs Cost estimates for Environmental and Social Mitigation will be estimated in the Environmental and Social Impact Assessment. The costs will include: - Compensation costs for loss of land, housing and other items, - Annual compensation for loss of production or livelihood, - Cost of resettlement or reconstruction of community infrastructure, - Cost of establishing and running institutions for monitoring, resettlement and

environmental management, - Cost of training personnel for new employment, - Cost of training personnel for environmental management, - Cost of infrastructure for environmental management, - Cost of relocating and preserving cultural property.

Sub-Task 10-4: Preparation of Final Cost Estimate All unit prices and lump sums will be divided into local and foreign currency components. Where pertinent, the foreign currency component would include the cost of: - depreciation of imported equipment, materials and supplies, - domestic materials of which the country is a net importer, - readily identifiable foreign components of domestic materials of which the country is a net

exporter, - wages of expatriate personnel, - overhead and profit of foreign firms. The local currency component would include the cost of domestic materials and supplies of which the country is a net exporter. The cost estimate will include the physical contingencies for construction. Physical contingencies are allowances for possible increases in costs as a result of physical conditions which adversely effect the construction or installation of the works and which could not be foreseen during the costing period. On the basis of the Project Cost Estimate and the implementation schedule, a disbursement schedule will be prepared detailing the expected timing of expenditure. The results of the final cost estimate will be presented in the Final Report on Cost Estimate, Economics and Finance. This will include in BOQ format the price make up of the Project, unit rates and the cost of individual section of the work.

Task 11: Construction Planning



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Sub-Task 11-1: Definition of Prospective Organisational Project Structure The Consultant will establish an organigram of the project organisation, which will describe the positions and the relationships of the involved parties to each other.

Sub-Task 11-2: Definition of Best-Suited Construction Methodology From the estimation of quantities and the type of construction to be performed, for each individual structure a certain construction methodology will be chosen. This will form the basis for the selection of construction equipment and productivity rates, labour requirements and other resources required for determining the unit cost rates. Furthermore, the selection of the construction methodology to be applied is a precondition for the establishment of cost estimates, construction schedules and general site layouts (location of construction facilities, site infrastructure, transport, etc.).This also comprises the staged planning of the river diversion (flood and flood-free periods) in connection with all other site activities. The Consultant will present in a layout and describe the main construction facilities and production bases. - Quarrying - Concrete aggregate production and stockpiles - Cement storage - Concrete production facilities - Crane and lifting facilities - Reinforcement workshop - Steel workshop - Mechanical workshop - Laboratories, offices and housing etc.

The description of construction facilities will also comprise the respective required capacity (e.g. m³ of concrete per day, tons of aggregate production per hour). Further to the assessment of the main construction facilities it will be also assessed what kind of machinery will be needed for construction purposes (e.g. sizing and number of dozers, roller compactors, drill rigs, shotcrete and concrete pumps).

Sub-Task 11-3: Assessment of Required Transport Logistic The Consultant will propose the most efficient ways of transport on site. The most suitable hauling routes (surface and underground) between different site areas and material borrow areas will be identified by considering all means of transport, such as: - Any kind of motor driven road vehicles (trucks, light vehicles); - Railway systems; - Mobile cranes, gantry cranes, tower cranes and cable cranes; - Helicopters (e.g. for installation of transmission line towers in areas difficult to access); - Short and long distance conveyor systems, etc. The Consultant will establish a general site layout which will show the sources of the main construction materials such as borrow pits, batching plant, areas of material storage / stockpiles and respective transport network linking these with the different construction sites such as main dam, coffer dams, tunnel access adits etc.

Sub-Task 11-4: Project Construction and Implementation Schedule



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The project work will be broken down into contract packages and individual items. This will ensure a clear definition of the work content as well as the proper coding of the activities. Typically the project description acts as a plan that defines all effort to be expended, assigns responsibility to specially identified organisational elements, and establishes the basis for scheduling and budgeting for the project. For each main work item an adequate construction method and average progress rate will be assumed, which are related to the equipment employed in the construction and its capacity. The work method and size of equipment will later be used to estimate the costs.

Sub-Task 11-5: Risk Analysis The inherent risks related to construction and operation could include (exemplarily): - Hydro-climatological risks: margin of uncertainties of river flow in quantities and spatial

distribution - geological and seismic risks: rock mass formations at dam and power house sites and

along tunnels, exposition to earthquakes and associated accelerations - geotechnical risks: dam stability, underground seepage at dam site, land slides at sites of

surface structures, access roads and transmission lines - operational risks: human errors in operation of the dam, power plant and transmission

lines - economic risks: power purchase prices, delays in implementation and construction of the

project, cost overruns.

Probability of occurrence and related grades of severity will be estimated based on experience and data obtained from similar projects (preferably of the region), and the economic impacts estimated. The impacts of the above risks on the economic viability of the project will be assessed in the frame of the sensitivity studies of the economic analysis.

Task 12: Economic and Financial Analysis The purpose of the economic analysis is to demonstrate that the project achieves optimum utilisation of resources and is of sufficient economic merit to justify the considerable investment. Generally, financing agencies wish to review and approve the results of the analysis prior to making any commitment on financing of the whole or of part of the project.

Sub-Task 12-1: Economic Analysis The economic evaluation of the project will be carried out in a cost-benefit analysis, where the costs of the project are compared with its benefits. The costs of the project comprise all costs incurred during implementation and subsequent operation of the project, i.e. investment costs, reinvestment costs and operation and maintenance costs. The benefits of the project are represented by the electric power and energy produced by it, by reliable water supply for irrigation purposes, by cost savings through flood control, by increased energy outputs through sediment control, improved flow regulation, etc. The costs of the hydropower project then are compared with the costs of equivalent thermal generation on a project basis. Hydroelectric energy replaces energy that, without the project, would have to be generated by thermal power plants. The benefit derived from the avoided cost of thermal generation thus has two components: the Capacity Benefit and the Energy Benefit. While the capacity benefit consists of the avoided capacity cost of the alternative plant (investment costs, reinvestment costs and fixed O&M costs of the thermal alternative), the energy benefit



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consists of the avoided operating costs of the thermal alternative, i.e. fuel costs and variable O&M costs. The economic feasibility of the project will be assessed by various evaluation criteria, such as Economic Internal Rate of Return (EIRR), Net Present Value (NPV), Benefit/Cost Ratio (B/C Ratio) and Dynamic Unit Cost (DUC). A sensitivity analysis serves to test the effects of changes in key parameters used in the economic evaluation. Parameters normally tested in the sensitivity analysis include changes in investment cost, changes in energy generation (e.g. due to variable hydrological / inflow scenarios), change in the fuel cost of the thermal alternative, discount rate and delay in construction.

Sub-Task 12-2: Financial Analysis The financial evaluation of a hydropower project generally has two objectives: - to assess the financial viability (profitability) of the project, and - to investigate its impact on the financial performance of the utility. The profitability of the project will be assessed by a simple cash flow analysis, which compares the annual streams of costs and revenues pertaining to the project, similar to the methodology used in the economic evaluation, whereas benefits are represented by the revenues from the electricity sold. All costs will be expressed in market prices; i.e. capital costs include taxes and custom duties. Shadow pricing is not applied.

The analysis will be carried out in constant terms, in order to avoid any distortions of the financial indicators caused by inflationary effects. Evaluation criteria for the assessment of project viability include levelised unit cost (financial dynamic unit cost), financial internal rate of return (FIRR) and financial cost coverage ratio. Their calculation will be based on the discounting technique. For the investigation of the financial performance of the utility, the cash flow in each year during the study period is relevant. The cash flow as set up for the calculation of the dynamic unit cost and the FIRR will be modified to include financing and be expressed in current prices. The liquidity position of the project will be assessed from the net cash flow (cash inflow minus cash outflow) in any given year. The financial evaluation will include a sensitivity analysis with regard to changes in investment cost, energy generation, tariffs, loan conditions and the like.

Task 13: Detailed Project Report (DPR)

Sub-Task 13-1: Draft Detailed Project Report On completion of the Tender Design the Consultant will present a Draft Detailed Project Report, based on the guidelines of the authorities and financial institutions. This report will summarize the results of the preceding studies and will include a synopsis of the Feasibility Study Report and an Executive Summary. The DPR will constitute a “bankable” document. It will therefor also include other information



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required by funding agencies, which are likely to be approached for funding of the project.

Sub-Task 13-2: Final Detailed Project Report In reasonable time after the submission of the Draft Detailed Project Report the Consultant will submit the Final Detailed Project Report incorporating comments of the Client and the authorities/agencies.

Task 14: Tender Documents

Sub-Task 14-1: Definition of Tender Lots The Consultant will, in close co-operation with the Client, break down the overall scope of works into several contract packages (tender lots). The number and size of the lots must be well balanced, since a high number of “small” contracts increases the competition on the market but also increases the organisational efforts and contractual interfaces. On the other hand a small number of “large” contract packages reduces interfaces and potential risks but also limits the international competition. For each lot a number of documents will be prepared as follows:

Part I: “Bidding Instructions”

Part II: “General Conditions of Contract”

Part III: “Special Conditions”

Part IV: “Technical Specifications”

Part V: “Tender Drawings”

Part VI: “Bill of Quantities”.

Sub-Task 14-2: Preparation of Part I: “Bidding Instructions” The purpose of the "Bidding Instructions" is to set the rules for the tendering contest. The instructions will inform tenderers of the tender period, special national laws and regulations, appropriate preparation and presentation of the tender, circumstances under which deviations from the tender documents and alternative tenders may be accepted, local participation required, currencies and exchange rates to be adopted for evaluation purposes, and the requirements for tender guarantees and contractors' insurances. Specimen forms incorporated in the Tender Documents can serve as a basis to complete the tender and are means to ensure completeness and uniformity of information requested from the tenderer. They may cover such aspects as an acceptable performance security, warranties, currency requirements, disbursement schedule for budgeting of the project, anticipated sub-contracts, programme of work and anticipated plan of operation, site requirements, manpower and key staff requirements, lists of construction equipment and plant, a list of materials demonstrating their origin and basic prices, and the type of contract agreement to be entered into. A list will be given as to the information required from the tenderer in the form of a memorandum to be submitted with his tender. Tenderers will have to provide this information in this form in order to be responsive. In the Bidding Instructions, the best information available at the date of issue of the Tender Documents will be given. This information includes, in particular, statements about local conditions such as location of the project, access possibilities and transport facilities,



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geological, hydrological, climatic, seismic and topographic data, availability of labour and materials, electric power and water procurement, local financial obligations, and other sources of information which provide tenderers with full background information for their tender preparation. The description of the project components will widen the tenderers' knowledge of the project, and the overall programme of works will highlight essential key dates based on the critical path method. These refer particularly to the interdependencies between the different contract lots.

Sub-Task 14-3: Preparation of Part II: “General Conditions of Contract” The Consultant’s preference would be for the use of the FIDIC Standard Form of Conditions, together with additional clauses of particular application. For these clauses the Consultant will use its own basic models, which are very similar to those given in the World Bank’s Sample Bidding Documents. With regard to the supply contracts, the Consultant would propose to incorporate the FIDIC Standard Form of Conditions for Procurement, as modified by amendments, and further conditions of particular application.

Sub-Task 14-4: Preparation of Part III: “Special Conditions” The Consultant will prepare the Special Conditions of Contract to modify, adjust and amend clauses of the General Conditions of Contract, taking into account the circumstances and location of the works. New clauses will be prepared to the Client’s regulations and interests, governmental restrictions and other matters related to the project. Special attention will be paid in the Special Conditions of Contract to country and/or Client specific issues like:

type and scope of securities (tender, advance payment, performance and maintenance),

health and safety regulations, including accident prevention,

environmental protection regulations, including the requirement to establish environmental protection plans for implementation during construction,

type and scope of insurances,

labour relations and laws,

restrictions and working hours,

defects liability,

site infrastructure,

certificates and payment procedures,

special risks,

force majeure,

Consultant's power and responsibilities,

price adjustment,

local taxation,

customs duties,

dispute settlement procedures.

The Consultant will discuss and agree on these issues with the Client at a very early stage of the present task.

Sub-Task 14-5: Preparation of Part IV: “Technical Specifications”

General Technical Specifications



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will describe clearly and in detail the scope of works, quality of materials and the requirements of workmanship, which the contractor is called upon to provide in carrying out the works. The description will be based on internationally recognised standards for materials and workmanship and will include instructions about installation methods and techniques, samples and tests required during the progress of the works. Where appropriate, reference would be made to standards of international status. Except where unavoidable, no proprietary product will be specified exclusively but rather quoted as illustration and endorsed "or similar approved".

Particular Technical Specifications

will be prepared to supplement and extend the provisions of the General Technical Specifications, taking into account the particularities of the project, physical characteristics, local conditions and circumstances requisite for the performance of the works.

Performance Specifications

will be prepared for items of plant and equipment, which will be designed in detail by the manufacturer. The specifications will detail the particular performances which the plant and equipment must achieve for satisfactory operation of the scheme, but will not unnecessarily restrict the manufacturer.

Data Sheets

for all specified parts will be provided, in which the tenderer shall insert individual dimensions and characteristics, which cannot be prescribed in the Technical Specifications and depend on the design of each individual manufacturer.

Sub-Task 14-6: Preparation of Part V: “Tender Drawings” The Tender Drawings, which are based on the drawings produced within the scope of the Detailed Design Stage, have to be in sufficient detail so that any prospective contractor can obtain a full understanding of the requirements of the respective contracts and may formulate his methodology for constructing the works accordingly. This applies to both construction and supply contracts. In the case of civil works' construction, the Consultant's practice is to prepare the tender drawings as detailed as possible leading to accurate Bills of Quantities. Exceptions to this level of detail are, with respect to civil works, items whose exact dimensions are dependent on details resulting from the award of other contracts covering hydro-mechanical, electrical and mechanical equipment. The Tender Drawings will be clearly marked as being for tender purposes only. In principle, the tender drawings will contain information on:

sizing and levels of structures and all their component elements to a degree of accuracy which is sufficient for tender purposes,

location and necessary provisions in the civil structures for the installation of main permanent equipment,

for underground structures, the design of temporary support, subdivided into support classes for tunnels, and the general support pattern for the major underground excavations with indicative lengths of rock anchors and bolts,



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the required foundation treatment and grouting, and the sequence of application of such works, with indications of lengths, spacings, grouting pressures, etc. The same applies to open cut excavations.

Furthermore, details will be indicated with respect to

excavation lines,

arrangement and dimensions of major block joints,

type and class of concrete (first/second stage),

embedded steel parts (typical).

Sub-Task 14-7: Preparation of Part VI: “Bills of Quantities (BoQ)” The Bills of Quantities will describe and quantify each work item, to enable the tenderers to formulate clear and accurate tenders. The bills will enable tender comparison and provide the basis for valuation of the works performed after award of contract. The Bills of Quantities will give identifying descriptions and estimated quantities of work, comprising the execution of the works, and will also include items for project components to be supplied and installed, indicating the local and foreign currency portion. The quantities will be determined from the project drawings. The quantities of temporary works, which cannot be taken from the drawings, will be additionally quantified. Typical items in a Bill of Quantities for civil construction works for which the unit prices will be estimated include:

Project Preparation and Pre-construction Costs;

Site Preparation (clearing and grubbing, overburden excavation, embankment, care of water);

Site Installation (mobilisation, installation, operation and maintenance, dismantling and demobilisation);

Foundation Excavation (clearing, grubbing, overburden excavation, rock excavation, backfill, care of water);

Underground Works (excavation through earth and rock according to respective classification, rock bolts and anchors, grouting, shotcrete, steel arches and lagging, concrete and concrete lining, care of water);

Foundation Treatment (overburden excavation, dental excavation, slush grouting, dental concrete, guniting, borings for curtain grouting including pressure testing and the supply of injection of grout material, borings for drains including fittings, care of water);

Structures and Components (various classes of concrete, cement, reinforcement, shutters, embedded parts);

Access Roads (clearing and grubbing, overburden excavation, rock excavation, embankment pavement, drainage structures, care of water).

The Bill of Quantities will be prefaced by a preamble defining the connection to the General and Special Conditions of Contract, Technical Specifications and Tender Drawings and how unit price items are to be measured. In the case of mechanical and electrical equipment, the aim would be to obtain a CIF price for supply to the project site with additional prices for storage, erection and testing in foreign and local currency.



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In the Price Schedule, the cost for the general spare parts and additional spare parts will be indicated. Also, prices for essential parts, which might later be subject to replacement, will be given in this Price Schedule. The schedules will allow costs of spare parts to be easily estimated if required at a later time.

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