Chapter 17: Guidelines for Countries Proposing Dams
As of March 2013
MCC will use the feasibility study of the proposed project as the basis to examine the following and make a determination on what supplemental studies, if any, are required to develop the project sufficiently so that Appraisal could commence:
- Preliminary description of rationale, including nature and measure of benefits, and beneficiaries (disaggregated by income, gender, and ethnicity).
- Confirmation supported by appropriate data and meaningful public consultation with potential beneficiaries, which may include income- and gender-based focus groups, that the proposed project is likely to deliver the stated benefits.
- Identification of the role of the dam in the strategic plan for water resources development and management at the national or regional levels and the role of the dam in the river basin strategic plan.
- Demonstration supported by appropriate data and information that the dam project is the result of a preliminary alternatives assessment involving key stakeholders representative of potentially impacted parties (by income, gender, age, ethnicity, etc.) including social and women’s government ministries and NGOs and potential beneficiaries, riparian communities and meaningful and participatory public consultations in the river basin.
- In the case of a dam developed on an international waterway, provide no objection statement of the countries sharing the waterway or a proof of notifications and consultations under process in conformity with the World Bank OP7.50 procedure.
- In the case of a dam affecting indigenous people, confirm with appropriate data that they have been meaningfully consulted utilizing gender-competent participatory processes and that their views and interests have been considered in the dam planning and preliminary design, in conformity with World Bank OP 4.10 procedure.
- Preliminary assessment of the water resources in the river basin, their quantity, quality, usages, and the role of the dam in achieving holistic and sustainable development for the overall river basin. Holistic, as used here, means that all water and development issues in the river basin have been considered in an integrated way.
- Demonstration that sufficient and reliable meteorological, hydrological and hydraulic data and studies have been provided in preliminary or feasibility reports on issues such as river characteristics, river flows, yields and regime, rare floods and their hydrographs, sediments transports, ground water pattern and its interaction with surface water, total solids in suspension, total dissolved solids, and specific substances in suspension and solution.
- A preliminary evaluation of the dam reservoir long term firm yield, based on sound hydrological models, to ensure that the reservoir will sustain its purpose(s) for the long term with acceptable reliability.
- Definition, assessment, and evaluation of current and projected land uses and occupation in the proposed dam site and reservoir area. Identification of possible physical cultural assets, specific natural habitats within the reservoir area and land resources management in the area for long term development.
- Determination that preliminary geological and geotechnical surveys have been conducted to determine the feasibility and the viability of the dam’s site, the imperviousness of the reservoir area and to identify the major faults and the treatments necessary for reservoir area, the dam foundations and abutments.
- Determination that the necessary materials to build the dam (earth materials, aggregates, rock materials for construction and protections, sand or crushed rock for filters and concrete, etc.) exist close to the site for the construction of the dam and appurtenant structures.
- A preliminary alternative sites and dam type assessment based on hydrological, topographic, geological and geotechnical data analysis.
- Preliminary design criteria, design and drawings, specifications and cost for construction, operation, maintenance, surveillance and inspection of the dam and appurtenant structures.
- A preliminary dam instrumentation and monitoring plan which will include the main parameters to be monitored, the instruments to be installed on the dam and appurtenant structures, and monitoring schedule in normal and emergency situations.
- A preliminary cost benefit analysis for the dam project, including the cost of producing the dam’s proposed services and goods (electricity, water for irrigation, drinking water, floods protection, river regulation, etc.).
- A preliminary description of the institutional framework and organization to build the dam and the schedule for the implementation of the dam project.
- A specific dam potentials risk assessment and classification according to the country regulations on dam safety and risk management or, in the case where there is no regulation, the classification according to ICOLD criteria.
- For a large dam project, provide a preliminary safety and risk management plan including the organization for the surveillance and inspection of the dam and preliminary floods emergency plan or elements.
- For a large dam project, provide a panel of expert’s review of all safety issues raised during the preliminary or feasibility studies according to the World Bank OP 4.37 procedures.
- A preliminary description of the institutional arrangement for dam operation, maintenance and surveillance for the dam’s safety regulation.
- Identification of related policy, legal, regulatory, and institutional frameworks, and general evaluation of their potential impacts and implications on project implementation.
- Identification of data gaps and areas that require more detailed, current or reliable information.
- Determination that satisfactory aerial photos and satellite images of the site, the projected impounded area and the watershed have been collected and are complemented by adequate topographic surveys and studies of the site. Integration of satellite imagery and topographical maps at the appropriate scale, identifying key elements of existing and proposed infrastructure, rights-of-way, and service areas. In addition, it may be appropriate to identify other geo-spatial data, including but not limited to census data, water resources, geological and geotechnical data.
Once MCC has made the determination to commence appraisal on a project, the infrastructure group will conduct the following assessments and identify key constraints.
Technical Assessment: Engineering
Evaluation of dam project planning process
- Review the dam project planning process to ensure that the project is consistent with the national, regional and river basin water resources strategic plan and is developed in the framework of holistic management of the river basin.
- Review and assess the project alternatives studies and verify that the project is the best alternative and option to achieve the project goals and purposes and that the alternatives studies and assessments have been conducted in conformity with recognized international standards. Recommend additional and further studies if required to improve option effectiveness.
- Review and assess the dam planning process to ensure that the views and interests of keys stakeholders including affected people, indigenous people if applicable and the general public have been considered in the project options and design.
Review and assessment of dam potential risk classification
- Review the preliminary dam potential hazards and risk assessment and verify the dam hazards and risk classification to ascertain that the classification is consistent with the country regulations or recognized international standards (ICOLD).
Topographic data and mapping assessment
- Review and assess all topographic and maps data and surveys available, evaluate their consistency for proper design of the project at feasibility level and, if necessary, provide a program for additional topographic surveys, including remote sensing methods (aerial and satellite photo), land tachometric surveys, GIS and all adapted methods, in order to provide accurate data at the appropriate scale on the dam site, the reservoir area and the watershed, to define land use and occupation, and to provide the topographic model of the dam site, the reservoir area and the watershed. In the case of modifications of existing dams, conduct bathymetric surveys to establish the actual characteristics of the reservoir area and a detailed topographic survey of the existing structures.
Geological and geotechnical studies review and assessment
- Review all geological data available (regional maps, boreholes logs, satellite and remote sensing images and photos, etc.); evaluate their completeness for a feasibility level analysis. Provide recommendations for additional data needed (e.g., geological regional maps collection, and/or detailed field geological surveys of the river basin, reservoir area and the dam site) to identify the geological features (e.g., existing parent rocks, faults and others major discontinuities, seismicity, ground water and its patterns, weak strata, interbeds and seams, soluble rocks) for the establishment of the dam site geological model and identification of construction materials sources.
- Review and assess all hydro-geological data and analysis and provide recommendations for complementary investigations, including geophysical surveys, drilling etc., needed to establish ground water patterns and/or ground water modeling and to identify potential leakage and seepage problems associated with the dam site.
- Review and assess all geotechnical data and analysis for the dam site and reservoir area and evaluate their adequacy for the proper design and treatment of the foundations and abutments of the dam.
- Review and assess the available geotechnical data on construction materials, including earth and rock materials, sand and gravel for filters, and aggregate, and evaluate their consistencies for the design and construction of the dam. Provide, if required, recommendations for additional detailed investigations and data collection to ensure proper design and construction of the dam and appurtenant structures.
Sites selection review and assessment
- Review and assess the site selected based on the socio-economic, topographic, geological and geotechnical investigations results.
Hydrological studies review and assessment
- Review and assess all meteorological, hydrological and hydraulic data for the river and neighboring rivers and tributaries to evaluate their quantity, quality and appropriateness for sound hydrological and hydraulic studies of the reservoir, rare floods estimation (peaks, volume and hydrographs), downstream flows and regime modifications, and their adequacy based on the size and complexity of the proposed dam.
- Review and assess the hydrological and hydraulic studies for water resources availability based on long-term records of river flows and water quality or simulations models using rainfall records for the catchment or stream flow of neighboring rivers and taking into consideration actual and forecast development of the basin.
- Review and assess the river sediment transport data, potentials impacts on the reservoir life and operation and the preliminary recommendations for watershed management to control sedimentation.
- Review the assessment of the reservoir long term yield and ensure that the analysis is based on sound hydrological models. Confirm the estimate and reliability of reservoir long term firm yields and ensure consistency with the project purpose(s).
- Review the preliminary reservoir operation rules according to the findings of long term reservoir simulations and firm yield evaluations and provide recommendations to modify these if necessary, based on the results of the reservoir simulation models.
- Review and confirm the results of the hydrological evaluation of the proposed project impact on the appropriate watershed, as needed.
- Review the estimation of rare floods (100, 1000, 10000 years return period floods, probable maximum flood (PMF), etc.) and their respective hydrographs for the determination of design and check floods for the design of the spillways.
- Review and assess the estimation and the definition of the design floods (10 to 100 years return floods depending on the size and potential risks of the works) for the design of river diversion structures for works protections during construction.
- If required, confirm that all necessary investigations have been completed to determine whether existing upstream dams can threaten the safety of the proposed dam as a result of poor design, weak construction, lack of proper surveillance and safety measures, etc., and that proper measures to mitigate these risks have been developed.
Dam and appurtenant structures design review and assessment
- In accordance with the dam potential risk classification, review the hydrological design criteria (100 years return period to PMF and their hydrographs) for check and design floods based on the country regulations or ICOLD guidelines if there are no regulations in the selected country.
- Review, according to the dam risk classification, the proposed structural design criteria for the spillways and structural elements of the dam and ensure that these are appropriate for the design of the dam and its appurtenant structures.
- Review and assess the proposed construction materials and foundation design parameters (density, shear strength, consolidation index, etc.) and the load cases considered. Ensure that the parameters are appropriate, adequate and derived from the results of tests available. Also ensure that the load cases are based on the specific features of the site and dam and are consistent with country regulations (if they exist) or with international standards (ICOLD).
- Review and assess the foundations treatment measures proposed in the feasibility or preliminary studies (key trenches, grouting, anchors, drainage systems, etc.) to ensure effectiveness and appropriateness with the problems identified by the geological and geotechnical investigations and laboratory tests results.
- Review and assess the dam type and cross section selection based on the site characteristics, the construction materials available, and the foundation characteristics. Verify the dam stability analysis and confirm that this is the best economical and technical option.
- Review and assess the adequacy of the spillways design for passing the check and design floods, and confirm the structural stability of the spillways structures during these events.
- Review and assess the adequacy of the design of outlet and river diversion structures and their capacity to discharge the works protection design discharge, to drawdown the reservoir in the required time span and also to deliver the ecological flow downstream.
- Review and assess all structural elements for environmental and social impacts mitigation, such as fish ladders, and verify their appropriateness and adequacy.
- Review all aspects of preliminary technical designs and proposed standards and confirm appropriateness of criteria, demand requirements and environmental and social factors.
Dam gates and hydro mechanical equipment
- Review and assess the design criteria, design and specifications of gates, valves, pipes, gantries, stand-by generators and miscellaneous equipment and identify data gaps where improvements to the design and specifications are necessary to ensure proper functioning, operation, maintenance and durability of this equipment.
Dam maintenance inspection and safety management program review and assessment
- Review according to the dam potential risks classification, the preliminary instrumentation plan, which is a plan for the installation of instruments to monitor and record the dam and appurtenant structures behaviors and the related hydro meteorological, structural, and seismic factors based on significant parameters to be monitored. Assess the adequacy of the plan.
- Review and assess the adequacy of the plan and preparation for the first impoundment of the reservoir including the rate of reservoir filling, the instrumentation and auscultation monitoring schedule and the warning levels for the main parameters, describing the dams and appurtenants structures behaviors during the first filling and the elements of the reports on first filling required.
- Review and assess the adequacy of the preliminary operation, maintenance and surveillance plan, which covers organizational structure, staffing, technical expertise and training needs, equipments and facilities needs to conduct these tasks.
- For large dams, review and assess the adequacy of the preliminary emergency preparedness plan which defines the role of responsible parties when dam failure is considered imminent or when expected operational flow release threatens downstream life, properties and ecosystems. The plan includes the following items: clear statements on the responsibility for dam operation, decision making and related emergency communications, maps outlining inundations levels for various emergency conditions, flood warning systems and procedures for evacuating threatened areas and mobilizing emergency forces and equipment and the cost related to such measures.
- Review and ensure that all appropriate environmental and social evaluations and engineering design and safety criteria are met.
- Review and assess the adequacy of the proposed river diversion works for the protection of the works during construction against flooding and recommend as necessary, elements to improve the river diversion measures for the construction of the dam.
Dam works specifications and cost analysis evaluation
- Review and assess preliminary specifications for the dam and appurtenant structures, evaluate their adequacy to provide sufficient pre-bid cost information with an accuracy of +/-30%.
- Review preliminary engineering designs. MCC’s engineering consultant should confirm that these designs provide sufficient pre-bid cost estimation to an accuracy of +/-30%.
- Review and assess dam project cost estimation and ensure that all costs have been considered. Recommend possible cost adjustments to fit the actual and forecast economic conditions.
- Evaluate proposed design standards and suggest alternatives when existing standards are not acceptable to MCC.
- Confirm assessment of availability of local materials, required plant and machinery.
- Identify other factors not identified during project studies, that can potentially affect cost or scheduling including site preparation, access roads for construction, utility provision (including possible encroachment and relocation), construction camps, environmental clean-up, and equipment mobilization and de-mobilization.
Institutional and regulatory framework for dam safety management assessment
- Review and assess the institutional and regulatory framework existing and proposed for dam maintenance and safety management to ensure that the dam will be operated, maintained and inspected according to the best international practices such as the ICOLD Guidelines for dam safety.
Coordination with Large Dams Panel of Experts
For large dam projects (large according to the ICOLD classification system), the selected country will appoint a panel of experts to review all the criteria, data, design and dam safety assessments to provide recommendations in conformity with the World Bank OP 4.37 procedures. The recommendations of the panel will be implemented during the overall process of design, construction and operation of the dam. The panel shall be involved in assessing and tracking the project from feasibility studies to the first filling of the dam reservoir.
Technical Assessment: Economic and Financial
The MCC economist responsible for the assessment will work to ensure that the proposed project complies with MCC Guidelines for Economic and Beneficiary Analysis. The economic rate of return for each project should be sufficiently high to warrant investment and eligible countries should have reviewed relevant governance practices, including laws and regulations, and undertaken reforms, as possible, to enhance the anticipated economic benefits generated by the dam project. Infrastructure input to this analysis may include the following:
- Identify benefits expected to flow from the projects in close consultation with the MCC economist, focusing on increases in incomes for workers, firms, and households disaggregated by income, gender, age, and ethnicity. Identify the beneficiaries, to the extent possible. Compare projected incomes and other benefits with and without the proposed project.
- Summarize the design standards, design life and cost estimates (capital and operations and maintenance) and confirm these are consistent with the assumed benefits and duration of the benefit stream. Note that the duration of the benefit stream is typically assumed to be twenty years. Assumptions that the duration is longer or shorter than this should be clearly justified.
- Confirm that the costs and project life are consistent with the engineering design.
- Complete a financial analysis for income generating subprojects.
Technical Assessment: Environment, Social and Gender
MCC environmental and social assessment experts will review projects for their compliance with MCC Environmental Guidelines, Gender Policy, and resettlement guidance, which include an expectation of compliance with host-country laws, regulations and standards, as well as requirements by which the host country is bound under international agreements. Particular attention must be paid to issues which generally arise including, but not limited to, land ownership and right of way, incursion into sensitive areas (reserves, parks, wetlands, etc.), drainage and erosion control (especially in hilly or mountainous situations). Assessment will also inform design by including the impact of the dam and construction on livelihoods, gender analysis of use, control of resources, design appropriateness, and how well gender is integrated into project design, participatory planning processes, and implementation.
- Identify country-, region- or sector-level assessments, strategies and commitments with respect to climate change and their relevance to compact activities.
- Identify climate change impacts (from the project) and risks (to the project) and corresponding mitigation and/or adaptation opportunities, as relevant.
- Review detailed description of current arrangements for ownership, management, maintenance, surveillance and inspection of dams and appurtenant structures, including details of the legal framework, administrative framework, funding arrangements and maintenance responsibilities.
- Review existing performance with respect to clarity and acceptance of arrangements and responsibilities, acceptance of dams funding reserves for maintenance and inspection. Identify causes of inadequate performance including legal or administrative arrangements, resources, technical capability and capacity and funding.
- Review and assess the impacts of sediment transport on the capacity of the reservoir and verify that watershed protection measures have been proposed for water and soils conservation to reduce the impacts of sediments transport on the reservoir life.
- Review and assess the dam safety program including inspection guidelines, instrumentation and monitoring guidelines, maintenance manuals and emergency action plan guidelines, to ensure that such plans are suitable for the dams and include responsibilities, resources, funding. Identify shortfalls with current arrangements and provide details of a program to strengthen dam safety management, including review of gender competency and cultural appropriateness.
- Review details of alternative maintenance funding options, including details of income derived from the project.
- As required, provide a summary of additional analyses required to bring planned dam maintenance and water management programs to an acceptable level, including additional studies for participatory and gender competent institutional strengthening, funding (responsibility and funding levels) and additional resources needed, etc.
Risk Management Assessment
- Identify significant risks to the project, with particular respect to construction cost increases, delays, sustainability of the scheme, local acceptance and take-up of benefits by various beneficiary groups disaggregated by socio-economics, gender, age, and ethnicity, and other factors affecting economic performance and distribution of benefits including potential resettlement, HIV/AIDS, human trafficking, child/forced labor. Identify and assess significant risks relating to durability, and confirm that design criteria adopted shall mitigate these risks within acceptable tolerance levels.
- Prepare a risk management plan to minimize the negative impact of the risks.
- Provide a summary of the technical and construction resources available in country, and experience with projects of similar size, nature and type.
- Provide details of implementation options available.
- Identify local factors that may affect the timely completion of the works, including transport to/from the location for the contractor’s equipment, fuel and other materials, seasonal weather patterns such as avoiding the wet season, or health risks including HIV/AIDS.
- Prepare an implementation program including contract awards, any approvals and permits needed, construction times, cash flow, government commitments and other hold points as appropriate.
- Recommend an appropriate procurement procedure, sequencing, and packaging.
- Provide a plan for construction supervision and quality assurance which covers the organization, staff levels, procedures equipment and qualifications for construction of the new dams or the remediation of an existing dam.