How Environmental Impact Assessments Promote Sound Tourism Investments

Heritage sites are structurally vulnerable, thus requiring extreme caution. Photo credit: ADB.

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An evaluation of possible project impacts helps preserve culturally and environmentally important sites and protect nearby communities.


Tourism has the potential to contribute to economic growth and generate substantial foreign exchange earnings. In many countries in Asia and the Pacific, tourism ranked high in government’s development plans, especially for those rich in tourism assets but lacking in manufacturing ability.

However, tourism development can also have adverse effects unless the proper measures are in place to ensure sustainable and inclusive growth.

Tourism assets include protected areas, such as cultural heritage sites. Because these sites are crowd-drawers and with national or international mandates to maintain or secure their value, managing them demands clear policies and careful development planning. These sites are mostly centuries-old and require extra caution when building structures or introducing improvements near them.

Tourism investments or projects that concern heritage sites, therefore, must be assessed properly to avoid or minimize any adverse impacts not only to these sites but to their surrounding communities as well. Facilities and service enhancement components of projects should also be evaluated.  

Conducting an environmental impact assessment can help decision makers identify, predict, evaluate, and mitigate adverse environmental impacts and consequences of development projects or activities prior to major decisions and commitments.

What is an environmental impact assessment?

A project funded by a government or international financial institution requires appraisal of its technical feasibility and financial and economic viability. In the wake of the damages caused by unregulated growth and rising public awareness, the assessment of potential environmental and social consequences was added since the late 1960s to feasibility studies. This is mainly through the environmental impact assessment.

Proponents must look at the environmental consequences and compare feasible alternatives that may reduce these consequences. The discussion on alternatives is described by academia as the “heart” of the environmental impact assessment process. All reasonable alternatives must be considered, including “no action.” At the end of the process, the authorities decide whether the project can go ahead, the conditions for it, and the measures that must be taken to reduce the residual adverse effects.

What are its objectives?

An environmental impact assessment has three objectives:

  1. Aid investment decision-making—specifically whether to finance or reject a proposed project.
  2. Optimize and inform project design by comparing alternatives and modifying components. Or design to minimize or avoid altogether the negative consequences from the outset.
  3. Mitigate the residual impacts by developing and implementing actions, like in the form of an environmental management plan.

In most countries and international financial institutions, project proposals are first screened to quickly judge their environmental impacts. Subsequently, they are classified as having low, medium, or high impact, which require different levels of intensity for assessment and management.

  • Minimal-low impact projects need no further assessment.
  • Assessment for medium-impact projects focuses on informing and optimizing the project design.
  • Assessing high-impact projects is critical to the investment decision. Projects can be vetoed on account of the dire social–environmental consequences revealed by the environmental impact assessment.
How it was applied on a cultural heritage tourism project

A proposed Asian Development Bank (ADB) project in Cambodia demonstrates how an environmental impact assessment process can optimize the design of a tourism investment.

Two project areas

In northern Preah Vihear province, 11 kilometers south of the famous Preah Vihear temple, which is a UNESCO World Heritage site, the local government proposed expanding and dredging a lake in front of the new tourism center near the project village. During the project discussions, environmental experts cautioned against its adverse impacts on ecology and water resources management. Instead, they suggested to fund only a small improvement around the lake, such as a garbage clean-up, and focus on village sanitation and waste management—which are indispensable for tourism and improves the wellbeing of communities. Lake and riverside investments were reduced to a simpler landing, walk paths, and viewing platform with budget saved to finance sanitation investment and basic solid waste management. Public toilets and standard latrines with septic tanks for homestay pilots were also suggested and considered by both project areas. 

The second one is near Phnom Da temple in Angkor Borei district, Takeo province, 80 km southeast of Phnom Penh. This district Phnom Da temple is one of these and is on the UNSECO’s tentative World Heritage list. The project intends to support high-value agriculture to strengthen the tourism–agriculture linkage and to supplement income during the low season. The environmental impact assessment flagged the potential pollution and health and safety issues associated with conventional commercial agriculture. It narrowed down activities to eco-farming, specifying the provision of water-saving equipment and trainings on safe cultivation and veterinary practices. Following the Ministry of Agriculture’s suggestion, pest and disease control to minimize chemical usage were integrated in the training plan.

How it protects cultural heritage

Originally, new stairways and viewing platforms were proposed close to the monuments in both project areas. This proposal was dropped as the Heritage Department of the Ministry of Cultural and Fine Arts (MOCFA) and UNESCO’s National Office in Cambodia, during the consultation, indicated that such could affect the integrity and authenticity of physical cultural resources.

For the second project area, the local cultural department also proposed placing a simple staircase and platform at a small archeological excavation site. According to the heritage protection law of Cambodia, light structures that are more than 30 meters from the cultural property boundary are allowed. The MOCFA considered the platform and railing as light structure and supported the investment. However, building the structure near the excavation site entails the transportation of construction materials and equipment and generates noise and vibration, which may structurally weaken the nearby heritage sites. These are typical residual impacts that the EIA process has identified and aimed to address (i.e. third objective) through developing mitigation measures.

How it shapes management plans

The environmental impact assessment was the basis for the mitigation measures that formed the physical cultural resource management plan—also a part of an environmental management plan. This plan specifies measures during design, construction, and operation phases. It stipulates the maximum height of buildings (two stories) and construction materials selection. It requires that heavy machinery and equipment should be avoided, and the use of manual construction and transportation methods are preferred to the extent possible. It is incorporated into the bidding documents. During implementation, a physical cultural resource conservation expert with engineering experience will be recruited to plan and supervise all work related to this.

In addition to the usual maintenance and supervision measures, the management plan specifies measures to prevent and control fire risks and electric hazard, drawing on the experience of recent projects in other countries.

Climate change risk assessment is part of the environmental impact assessment process for ADB. Two-thirds of the project village in this district is flooded during raining season, and climate change is expected to make the situation worse. Extra caution in the location and choice of technologies for some project structures, such as underground septic tanks to avoid inundation and related health hazards, was recommended.

Why stakeholder participation is important

Meaningful consultation begins with full disclosure of information.

Following the completion of the assessment, the entire draft, including the environmental management plan, was translated into Khmer and disclosed at both project areas and among key stakeholders.

To allow sufficient time for the stakeholders to digest the information, the last and most comprehensive round of consultation was conducted about a month after the disclosure.

Key stakeholders, such as the Ministry of Environment, reviewed and provided written comments. The final assessment, specifically the management plan, incorporated all comments to facilitate domestic environmental compliance.

Measures to promote sustainable tourism

Overtourism is a major cause for deterioration of heritage sites. This might not be an issue for Cambodia in the short term given its small population and the time it will take for international tourism to recover because of the coronavirus disease (COVID-19) pandemic. Nonetheless, the environmental management plan recommended to identify the maximum number of tourists allowed per day or year through a survey and data collection during operation for rational planning of tourism development and expansion of public utilities and services.

With a $3 million investment, the project can support the basic sorting and collection of solid wastes, but not the downstream garbage disposal. The environmental impact assessment suggested that garbage disposal in both project areas is primitive, with no public funding for proper disposal facilities in the foreseeable future. This is a common challenge in rural Asia. Tourism development however demands decent sanitation and hygiene conditions, including sewage, excreta, and garbage management. As tourism in the project areas develops, further work is needed to identify suitable sanitation technologies that are compliant to basic standards, cost-effective, and easy to build, operate, and maintain by local people.



Asian Development Bank (ADB). Cambodia: Community-Based Tourism COVID-19 Recovery Project.

A. Pedersen.2002. Managing Tourism at World Heritage Sites: A Practical Manual for World Heritage Site Managers. Paris, France: UNESCO World Heritage Centre.

International Association for Impact Assessment (IAIA). Principles of Environmental Impact Assessment Best Practices.

M. Helble and A. Fink. 2020. Reviving Tourism Amid the COVID-19 Pandemic. Manila: Asian Development Bank.

Xin Ren
Senior Environmental Specialist, Office of Safeguards, Asian Development Bank

Once an ADB safeguard reviewer, Xin Ren now works on environmental issues in rural sector. Prior to ADB, she worked at World Bank on environment in diverse sectors. She also worked at UNEP and in the People’s Republic of China on waste management and clean production, and at UNFCCC on climate change.

Leonard H. Leung
Natural Resources and Agriculture Economist, Southeast Asia Department, Asian Development Bank

Leonard has worked in the agriculture, energy, and transportation sectors, covering sovereign lending and project-finance. He conducts integrated financial and economic analysis to identify risks and mitigation measures, inform financial structuring, and confirm project viability.

Asian Development Bank (ADB)

The Asian Development Bank is committed to achieving a prosperous, inclusive, resilient, and sustainable Asia and the Pacific, while sustaining its efforts to eradicate extreme poverty. Established in 1966, it is owned by 68 members—49 from the region. Its main instruments for helping its developing member countries are policy dialogue, loans, equity investments, guarantees, grants, and technical assistance.

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