Impact assessment: tiering approaches for sustainable development planning and decision-making of a large infrastructure project

Figures & data

Table 1. Tiered approaches to environmental assessment. 1996; Nooteboom 2000; Fischer 2006a; Nobel and Nwanekezie, 2017).

Advantages of tiered approaches

Dangers of tiered approaches

Allow to cover different types of impacts and mitigation actions, from large scale, cumulative and generic to small, specific scales and local effects. Refines the scope of impacts and alternatives and reduces the time and costs of lower assessment tiers (‘funneling effect’) Allow adjustments to decision-making systems while the process evolves If the scoping process at each assessment tier is transparent, participative and flexible to determine impacts and alternatives relevant to the decision making it provides a useful and critical information to practitioners, planners and decision-makers about political priorities that could not be realized without those processes.

The interactions between assessment tiers depend on the possibility and willingness to coordinate the different tiers and to use the lessons learned in the previous tiers. If timeframes among tiers are not coordinated they may overlap or become outdated or disconnected. If decision-making systems at strategic levels are not binding, then there can be no ‘funneling effect’ nor a credible assessment at lower tiers The tiering order is largely determined by the decision-making system, the legal requirements and the power and competency of the responsible agencies or by the governance systems.

Figure 1. Linden—Lethem road corridor.

Source: Guyana Lands and Surveys Commission.

Table 2. Objectives of the assessment tier.

Assessment tier	Objectives
CEA	Analysis of key issues Description of the social and economic importance of the environment in the country Description of environmental policy and institutional framework for management
SESA	Ensure a strategic, systemic and broad perspective in relation to environmental issues within a sustainability framework Identify, select and discuss major development options toward more sustainable decisions (intertwining biophysical, social, institutional and economic issues) Identify strategic opportunities and risks Identify cost-saving and other beneficial changes from alternatives exploration Suggest follow-up programs, through strategic management and monitoring Ensure participative and transparent processes that engage all relevant stakeholders through dialogues Ensure that transboundary impacts are considered in the decision-making process (ESPOO convention)
ESIA	Ensure that environmental and social factors are considered in the decision-making process Ensure that possible adverse environmental impacts are identified and avoided or minimized Ensure implementation of a monitoring program (if needed) Inform the public about the proposal and give people the opportunity to identify problems

Figure 2. Outcomes of the scoping exercise.

Figure 3. Societal pillars.

Figure 4. Key strategic issues for the strategic environmental and social assessment of the Guyana-Brazil project.

Figure 5. The assessment process and critical decision moments.

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