WHAT IS AN 'IMPACT'?
Examples of different types of impacts are:
  • adverse and positive or beneficial
  • direct and indirect
  • temporary and long-term
  • reversible and irreversible
  • actual and perceived
  • quantitative and qualitative
  • physical
  • socio-economic
  • cumulative

Impact assessments will also consider how impacts are distributed across time, space and different groups of people.
The terms “impact” and “effect” are frequently used synonymously. In New Zealand under the framework of the Resource Management Act 1991, "effect" is the more commonly used terminology.
WHAT IS THE ENVIRONMENT?
Impact Assessment takes a holistic view of the environment, to encompass physical, socio-economic and cultural factors. The RMA definition of the environment is a good place to start:
"environment includes--
a) ecosystems and their constituent parts, including people and communities; and
b) all natural and physical resources; and
c) amenity values; and
d) the social, economic, aesthetic, and cultural conditions which affect the matters stated in paragraphs (a) to (c) or which are affected by those matters".
Environmental impact assessment (EIA) is a proactive planning and decision-making process that has an important role to play in identifying impacts, assessing risks, and evaluating the costs and benefits of development projects. Environmental impact assessment aims to avoid adverse and costly changes in the environment, to strengthen positive development outcomes and resilience.
Developers may see the EIA process as another set of hurdles to jump before they can proceed with their project. However, EIA can be of great benefit to them, since it can provide a framework for considering location and design issues and environmental issues in parallel.
Some EIA systems or jurisdictions constrain EIA to the analysis of impacts on the biophysical environment while others include the social and economic impacts of development proposals. Some systems (e.g., African Development Bank) use the expression “Environmental and Social Impact Assessment” to emphasize the inclusion (and the importance) of the social impacts. Other forms of IA focus on specific type of impacts (e.g., Social IA, Health IA, Ecological or Biodiversity IA). These may be carried out independently, but also in a joint exercise with other IA. It is desirable to integrate the environmental, social and economic dimensions of impact assessment (unless you are legally constrained from doing so).
Owing to the different professional skills involved, it is common practice in EIA Reports to address environmental issues separately, for example:
  • Landscape and visual impacts
  • Ecological Impacts
  • Impacts on the marine environment, marine systems and coastal processes
  • Cultural heritage impacts
  • Geological and soil impacts
  • Impacts on surface and groundwater
  • Public amenity/recreation impacts, outdoor access
In many EIA Reports, sections or chapters can be further subdivided, each being written by a separate author with specialist knowledge (for example, an ecology chapter divided into aquatic and terrestrial ecology). In order to ensure authoritative assessment, different authors should present their own conclusions; but the EIA Report team co-ordinator should ensure that all of these differing elements are consistent and drawn together in an integrated and understandable presentation.
Integrated IA is often employed for:
  • Large-scale developments
  • Development in environmentally sensitive locations
  • Development with particularly complex or potentially hazardous effects
For other developments, particular types of IA may be employed on an as-needed basis.

KEY BENEFITS OF EIA

Early identification of environmental constraints and impacts
EIA can result in an improved project design that:
  • is better suited to both the local environment and to project beneficiaries;
  • supports project sustainability and resilience;
  • contributes to smoother project construction and operation; and
  • allows for the avoidance of unnecessary expenses e.g. environmental fines, environmental clean-up or remediation costs.
When a project is well-suited to the environment, when its vulnerability to hazards and environmental change is minimised, and when it is operating efficiently and effectively, a proponent is likely to gain the greatest possible value from project investment, while government and the community are likely to gain the greatest possible value from project development.
Early identification and improved calculation of project costs
Provision of a level of certainty for all stakeholders
EIA can provide a level of certainty for all stakeholders because it outlines environmental performance and management standards that must be met by the project proponent. Proponents know what levels of performance and management they are expected to adhere to; government knows what levels of performance and management it must monitor; and the community knows the performance and management conditions on which development consent has been granted.
Fostering of social acceptance of a project
If the EIA process is participatory and inclusive of local stakeholders, including the directly affected community and land/resource owners, it can help to foster social acceptance of a project. Proponents are more likely to avoid major objections to their project, as well as delays in project implementation or disruptions to project operation, when the EIA process invites stakeholder participation in development planning and assessment, and requires proponents to recognise and address stakeholder concerns.

The Process and Stages of Impact Assessment

Engagement with the affected communities and other stakeholders should occur throughout all the stages of an EIA, and most particularly at the scoping stage.

Affected communities know the environment better than anyone else, and can provide valuable information that can improve the assessments and project outcomes.

Screening - is an EIA needed?

Project screening narrows the application of EIA to those projects that may have significant environmental impacts. The definition of significance with regard to environmental effects is an important issue in EIA. It may relate to scale of development, to sensitivity of location and to the nature of adverse and beneficial effects.

Screening may be partly determined by the planning framework - for example, if a development is located within an Outstanding Natural Landscape, a landscape and visual effects assessment is likely to be required. Likewise, where a proposed development will generate a certain number of vehicle movements, a traffic impact assessment may be required.

Scoping + Terms of Reference

It is important that environmental assessments are individually customised to address those aspects that are of most relevance to stakeholders. Customisation usually occurs during the scoping phase and results in the preparation of terms of reference (ToR) for an environmental assessment.

Environmental assessments that are not guided by ToR are likely to be unnecessarily long and complex, and may provide limited useful information to inform government’s decision-making process. The length of the ToR will vary depending on a project’s environmental risks or anticipated impacts. Projects posing a high level of risk, with significant, anticipated impacts will have longer ToR and be required to provide more information than low risk, low impact projects.

Description of Proposal + Consideration of Alternatives

The description of the project/development action includes a clarification of the purpose and rationale of the project, and an understanding of its various characteristics – including stages of development, location and processes.

The consideration of alternatives seeks to ensure that the proponent has considered other feasible approaches, including alternative project locations, scales, processes, layouts, operating conditions and the ‘no action’ option.

Baseline Information

The description of the environmental baseline includes the establishment of both the present and future state of the environment, in the absence of the project, taking into account changes resulting from natural events and from other human activities.

The gathering of appropriate baseline information is a critical part of the EIA process. Gaps, limitations and assumptions made in the gathering of data should be acknowledged. Where possible it should be made clear how they will be addressed in the assessment.

Prediction and Assessment of Impacts

The prediction of impacts aims to identify the magnitude and other dimensions of identified change in the environment with a project/ action, by comparison with the situation without that project/action. Predicting environmental impacts involves two main elements of work:

  • Anticipating, modelling, predicting or forecasting the changes that would be brought about by the project at all of its life stages, often compared to baseline, and/or predicted changes without the project.
  • Explaining, in a rational, consistent, impartial and transparent way, the significance of the changes.

An important part of the assessment includes actions that can be taken to to avoid, reduce, remedy or compensate for any significant adverse impacts. Management Plans may form part of this work. Actions that can increase positive impacts should also be identified. In some instances, identification of these mitigation actions can result in amendments to the proposal.

Presentation of EIA Report + Decision-Making

An EIA Report should:
  • be a “stand-alone” and complete document (though not necessarily a single volume)
  • provide enough detail to allow readers to form an independent judgement
  • be unbiased, neither advocating the project nor attempting to serve public relations purposes
  • avoid technical discussion and terminology except where absolutely necessary
  • include a Non-Technical Summary (NTS) setting out the main findings of the EIA Report in plain English.