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Introduction A Good Technical Guideline of MoIT

In Vietnam beside economic values, small hydropower plants caused various adverse impacts on the natural environmental (change in hydrological regimes, shortage in water at downstream; erosion; deforestation; damage of biodiversity and biological resources); social conditions and environmental risks. The water regulation of small hydropower plants may significantly contribute in the serious consequences of flooding in the Central Region in months of October, 2020. However, so far, environmental and social impacts and management of this type of energy projects are not properly concerned in project appraisal and management. Therefore, to improve this issue the following best “Environmental and Social Guidelines for Small Hydroelectric Projects, prepared by: Le Trinh (Assoc. Prof. Dr. Env. Sci., Consulting Team Leader, Chief Editor), Vu Ngoc Long (Dr. Ecol. Sci., Tran Quy Suu (MSc., Social Specialist, ADB), Le Quang Huy (MSc., Hydropower Specialist) for Ministry of Industry and Trade (MoIT) in November 2016 under REDP (SECO TF098460) are introduced to be applied.


1.1. The Needs

In Vietnam there are over 1,000 locations that have been assessed as capable of developing hydropower projects with capacity below 30 MW. Until 2016 approximately 190 small hydropower projects have been constructed and another 456 projects with a total capacity of 6,349 MW are under study.

According to Decision No. 2394 /QD-BCT dated September 1st, 2006 of MoIT stipulating the classification of installed capacity of hydroelectric and micro-electric machines as follows:

-  Small hydroelectricity: Installed capacity is greater than or equal to 1 MW and less than or equal to 30 MW (from 1 MW to 30 MW).

-  Micro hydro: installed capacity is less than 1 MW.

However, at present, the impacts of these projects on the natural and social environment are causing concern to state management agencies on natural resources and environment, and social media. In the past few years, there have been hundreds of articles, dozens of seminars reflecting the negative ecological and social impacts of small hydropower projects. In February 2012, MoIT has requested to the Prime Minister to remove 324 small hydropower projects. According to the Standing Committee of the Central Highlands Steering Committee: to February 2014, the Central Highlands provinces and the districts bordering the Central Highlands have eliminated 167 small hydropower projects, with a total capacity of 617.36 MW and 75 potential project locations , with a total capacity of 135 MW.

The main reason is that in addition to deliberately not complying with the laws on environmental protection of many investors, the implementation of legal regulations and environmental management of small hydropower projects are still weak; State management agencies, investors, contractors, and consulting units are also limited in understanding, awareness, lack of technical documents, experiences, lessons on environmental and social impacts of this type of project. Therefore, MoIT wishes to develop technical guidelines to apply to all small hydropower projects in Vietnam in order to improve compliance with legal regulations on natural resource, environmental and safety in the direction of sustainable development of this project type to continue developing small hydropower projects. Environmental and Social Guidelines, referred to as“ Guidelines” should be issued by the MoIT.

1.2. Goals and Requirements of the Guidelines

(i) Instructions aimed primarily at:

(a) Governmental management agencies;

(b) investors, contractors, consultants

and (c) commercial banks in the appraisal, design, construction, operation and management of projects to negative impacts of small hydropower projects on natural and social environment;

(ii) Guidance covering all phases of small hydropower development projects: planning, preparation, appraisal, construction, operation and dismantling.

(iii) Guidance helps relevant units and individuals: clearly identify issues, impacts and mitigation measures, and foreseen negative impacts in accordance with actual conditions and in accordance with regulations of Vietnam and international organizations. The guide also outlines the implementation process.

(iv) The Guidelines are compiled in a practical, easy-to-understand form; easy to apply. Therefore, the capacity is not too long; the social and environmental issues are fully mentioned, especially for small hydropower projects. The basic contents are outlined in approximately 100 pages; technical details for individuals and units needing deeper understanding are included in the attached appendix.

(v) These guidelines are based on the legal regulations on the protection of the environment and natural resources of Vietnam, the environmental and social safeguard policies of many international organizations, and guidance documents, including reference to the research results of MoIT in 2010 (Environmental Guidelines for Hydroelectric Projects in Vietnam, prepared by Boffa Miskell, Oct. 2010), combined with the results of actual surveys by the authors of this Guidelines at a number of small hydropower projects in different regions in May 2016.


The main subjects to use the Guidelines are the units and individuals involved in the management, consulting, investment, construction and operation of small hydropower projects. The "Guidelines" will help:

State management agencies (MoIT, Natural Resources and Environment - MoNRE, Agriculture and Rural Development MARD; Planning and Investment - MPI; Departments of Industry and Trade, Natural Resources and Environment, Agriculture and Rural Development in provinces with small hydropower projects: to identify key environmental and social issues to consider during the appraisal of the project's social and environmental impacts of project during the process of project site selection, design, construction and operation in accordance with Vietnamese law and compliance safeguard policies of international donors (if any).

Developers (small hydropower developers): to identify key environmental and social issues that need to be considered during project formulation and during project site selection, design, build and operate and consider the application of negative impact mitigation measures in each phase as outlined in the "Instructions" to manage the environment in accordance with Vietnamese laws and regulations and comply with safeguard policies of international donors (if any).

Construction contractors: to identify key environmental and social problems that may arise during construction in order to formulate and implement a “Construction Environmental Management Plan - CEMP” with appropriate mitigation measures, outlined in the "Guidelines" to comply with national technical regulations (QCVN), environmental standards and environmental management in accordance with Vietnamese law and comply with safeguard policies from international donors (if any).

Consulting units: to identify key environmental and social issues and solutions to minimize negative impacts on the environment and society during all phases of the project to help the investor in preparation of environmental impact assessment (EIA), Environmental Management Plan (EMP) and implementation of environmental monitoring in the phases of project preparation, construction and operation complying with the Vietnamese law and safeguard policies of international donors (if any).

Commercial banks: to identify key environmental and social issues to consider in the process of evaluating the socio-economic efficiency and environmental impact of the project from the project's formation stage and implementing credit work towards linking economic development with environmental protection and social security in accordance with the law of Vietnam and safeguard policies from international donors (if any).


This technical guideline has been compiled according to the legal and technical documents outlined in the Section of References at the end of this document.


This document is not a specific guide to “Environmental impact assessment”; nor is it a guide to the preparation of an "environmental management plan". Such in-depth technical guidelines are outlined in many international and Vietnamese documents.

"Environmental and social guidelines" is a document serving state management agencies, investors, contractors, consultants and commercial banks in the appraisal, design, construction, operation and management of hydropower projects ensuring to minimize the negative impacts on the natural and social environment, so are presented briefly and concisely with 3 main contents: (a) Identification of environmental and social impacts; (b) Adverse impacts and mitigation measures; (c) Responsibilities of stakeholders in the environmental management of small hydropower projects.

The cycle of a project, including a small hydropower project, needs to go through 4 stages:

(a) Project preparation stage, including: concept formation; pre-feasibility study, feasibility, design, appraisal;

(b) Construction stage;

(c) Operation stage;

(d) Demolition stage, not taking into account monitoring and evaluation of project implementation results.

According to Vietnamese regulations and many international organizations, project management work, including consideration of environmental issues, should be implemented from the project preparation stage. A diagram of environmental review and management content and responsibilities of the parties involved in environmental management is shown in Figure 1.

Follow the cycle above depending on the environmental management responsibility of the user of the Guidelines should:

a. Consider Part One of the Guidelines: to know at each project stage what potential environmental and social impacts are likely to occur;

b. Next: review Part Two of the Guidelines: to know corresponding to each negative impact of the project in each stage what mitigation measures to be applied (for prevention, control, treatment; compensation);

c. Next: review Part Three of the Guidelines to determine which units and individuals are responsible for environmental and social management at each stage of the project.
Figure 1. Diagram of project implementation and environmental management stages
For individuals/entities using the Guidelines to have a deeper understanding of each subject matter: detailed instructions can be found in the Appendixes:
- Appendix 1: Potential social and environmental components that will be affected by hydropower projects;
- Appendix 2: Process and method for environmental monitoring in hydropower project stages;
- Appendix 3: Monitoring and evaluation methods for compliance with environmental management requirements in the construction stage of hydropower projects;
- Appendix 4: Sample form of record of noncompliance and request for corrective actions;
- Appendix 5: Environmental flows and calculations of environmental flows;
- Appendix 6: Social safeguard  and resettlement policies of Vietnam and international financial institutions.
- Appendix 7: Guidelines for the development of resettlement plan.
- Appendix 8: Guidelines for formulation of ethnic minority development plans.
Appendix 9:  Guidelines for environmental grievance process.


The schematic diagram of a hydropower plant with a reservoir (including capacity types) is shown in Figure 2.

Figure 2: Schematic diagram of a hydropower system with reservoirs

According to the method of exploitation of the reservoir, small hydropower can be divided into 2 main types:
a.  The plants do not have regulation reservoirs.
b.  The plants with regulation reservoirs.
By location, small hydroelectric plants can be classified into two main types:
a.  Horizontal and post-dam location plants,
b.  Plants of path type.
The characteristics of each type of small hydropower plants are summarized below.

5.1. The plants do not have a regulation reservoir

With the plant using basic flow, the reservoir  has no regulation capacity, that is, no ability to store water during the low time of the power system to generate electricity during peak time of the power system. The natural flow to the facility line and the generation flow is virtually unchanged. The water level in the reservoir is always equal to or greater than normal water rise level (WRL).

5.2. The plants with regulation reservoirs

With a plant with a regulating reservoir,  the reservoir has the ability to store water at low time to generate electricity at peak times or store water in a period of full water to discharge into a low water period. Over regulation time it can be divided into:
- Short-term regulating reservoir: regulating daily and weekly.
- Long-term regulating reservoir: Generally small hydroelectricity does not have long-term regulating reservoir. However, it is not excluded that the investor may construct reservoir what is large in comparison with the total flow to the dam site in the small-scale basin.
To judge the regulation level of the reservoir's water flow, it is based on the value of the relatively useful capacity of the reservoir β. It is the ratio of the effective capacity of the reservoir Vh to the average annual flow of averaged over many years W0 at the dam site, b = Vh/W0 
- When β> 0.3 to 0.5 → calculated according to the regulating reservoir for many years;
- When 0.02 ≤ β ≤ 0.3 → calculated according to the annual regulating reservoir;
- When β ≤ 0.02 → calculated according to the day and night reservoir regulating or no regulating.

5.3. Plants of horizontal and post-dam location

Hydropower plants behind the dam and across the dam generate electricity thanks to the water column generated by the pressure line (dam and water inlet). The main feature of this type of plants is that the water generated from the reservoir will discharge directly into the river section after the dam, and will not result in a e river or stream of complete water shortage. With the structure of the plants of horizontal and post-dam water intake gate in combination with the plant is part of the pressure line. Normally, the plants of horizontal dams are applied with low-medium low water column (less than 40 m). Figure 3 shows a type of the plants of horizontal dams.

Figure 3: Horizontal dam type hydropower plant

Figure 4: Post-dam type plant

With the post-dam hydropower plant, the water intake is separated from the plant. Normally, the water column applied for this type is from 30 - 40 m or more. For small hydro projects with a capacity of N <30 MW, the expected height of the plant after the dam can be up to 50-60 m corresponding to the maximum height for grade II concrete dam on stone foundation according to Vietnamese Standards QCVN 04 - 05: 2012 / BNNPTNT. Figure 4 shows one type of post-dam type plant.

5.4.  Plants of path type

The path-type plant takes advantage of the difference in river elevation between the dam and the plant to generate electricity, i.e., the plant is not on the pressure line or pressurized tunnel. The following figures show the pressurized and unpressured pipeline-type plant.  The hydropower characteristics relate to the primary environment of this type plant is the flow from the dam to the plant completely altered from nature.

Figure 5: Non-pressurized path plant

Figure 6: Pipeline type pressurized hydropower plant  

The project's impact scope may include:
a.   The reservoir area and the river section upstream of the project and the river sections and areas adjacent to the reservoir.
b.  Areas for main works construction: dams, spills, energy lines, factories, transformer stations, transmission lines.
c.  Area of ​​ancillary works: concrete production facilities, material mines, storage yards, disposal sites, construction roads in the construction site; worker camps.
d.  River basin area downstream of the dam: from dam to plant (with access facility) and river /stream behind the plant and surrounding areas.
e.  Settlement, production and business areas may be affected and resettlement area (if any).
Objects affected by the project in each area include: physical environment components (quality of air environment, water environment, soil environment; hydrological and hydraulic regime, microclimate; erosion, sedimentation;…); the components of the biological environment (terrestrial, aquatic ecosystems, forest resources, fisheries, biodiversity) and social factors (ethnicity, culture, occupation, income….
In this "Guidelines" the environmental and social issues of the project in the above 5 areas are considered.
Please find detailed impact identifications, mitigation and management measures in all project stages in the full “Environmental and Social Guidelines for Small Hydroelectric Power Projects” (2 volumes), prepared by VESDEC experts for MoIT under SECO - WB project, November 2016.

Author: Assoc. Prof. Dr. Le Trinh

Source: VESDEC

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Name: Assoc. Prof. Dr. Le Trinh
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