Environmental Impact Assessment (EIA)

Environmental impact assessment (EIA) is a procedure that ensures that the environmental implications of
decisions are taken into account before the decisions are made. EIA is one of the older and most institutionalised procedures, and refers primarily to the environmental assessment of project level interventions. It is the one framework that is most firmly embedded in national legislation. In the European Union, EIA is obliged through directive 85/337/EEC of 1985, which was amended in 2003 (Directive 2003/35/EC ). EIAs are carried out for projects. Whether or not the project itself is needed, is not addressed by an EIA. The Strategic environmental assessment (SEA) process can be used instead.

During an EIA procedure environmental consequences of projects are identified and assessed before authorisation is given to the project. The assessment could lead to making modifications to the project, for example to mitigate or reduce the expected environmental impacts. Public involvement is a key element of the EIA procedure. The public is informed of the decision afterwards.

The process involves an analysis of the likely effects on the environment, recording those effects in a report, undertaking a public consultation exercise on the report, taking into account the comments and the report when making the final decision and informing the public about that decision afterwards. The International Association for Impact Assessment describes the following steps as being part of an EIA process: screening, scoping, examination of alternatives, impact analysis, mitigation and impact management, evaluation of significance, preparation of environmental impact statement (EIS) report, review of the EIS, decision making and follow up. Note that not all these steps are specifically mentioned in  the EU EIA directive.

  • Screening:  process of determining whether an EIA is required for a specific project.
  • Scoping: identifying the impacts that are likely to be important.
  • Examination of alternatives: process of determining the environmentally most desired policy option.
  • Impact analysis: process of identifying and predicting the effects of the proposal.
  • Mitigation and impact management: process to establish measures (or mechanisms) to minimise negative effects.
  • Evaluation of significance: process of evaluation if the impacts that cannot be mitigated are acceptable as compared to the benefits stemming from the proposal.
  • Environmental impact statement (EIS) report.
  • Review of the EIS: process of assessing the quality of the report.
  • Decision making: approving or rejecting the proposal (although arguably not occurring within the EIA process).
  • Follow up: process of monitoring impacts and effectiveness of mitigation measures as well as reflecting on the EIA to strengthen future applications.

EIA procedure stages

Further information on the EIA scheme can be found at: http://ec.europa.eu/environment/eia/home.htm

Original text of the EIA Directive and its amending acts: http://europa.eu/legislation_summaries/environment/general_provisions/l28163_en.htm

Application of GIS in the process of Environmental Impact Assessment.

Geographical information systems can be applied at all EIA stages. EIA is a decision process, which aims to both identify and anticipate impacts on the natural environment. The interface between these two components produces several effects, which will generate specific impacts. GIS can also be explored within the EIA process to improve different features, mainly related to data storage and access, to the analytical capabilities and to the communicability of the results. The development of such a system will allow a more realistic approach to the environmental descriptors and a better understanding of their interrelationships. GIS will bring to the EIA process a new way of analyzing and manipulating spatial objects and an improved way of communicating the results of the analysis, which can be of great importance to the public participation process.

The use of GIS in the EIA process, where public participation is of great importance, requires the development of applications allowing a better understanding of spatial phenomena. During the EIA process many different variables and phenomena presenting complex interrelationships, which vary in space and time are considered. These procedures involve technical analysis that includes changing assumptions and priorities and descriptions of significant visual and audible impacts.

The capabilities of GIS in the EIA process are:

  • It is possible to store large amounts of different kinds of data. The access to these rich databases allows the performance of dynamic queries based on real world representations.
  • Concerning the analytical capabilities, some potential functionality can be added such as the use of interactive video and digital sound associated with zoning maps, to help planners and decision-makers to visualize and better evaluate the impact of a new infrastructure. Other capabilities are related to the integration of spatial simulations associated with real images and to stereoscopic aerial photographs in order to get an improved visualization of the phenomena and their evaluation in real time.
  • The results of EIA correspond to compressed information to synthesize in a small number of descriptors the complex and diversified universe that has been analysed. In a GIS, the improvements in the communicability of the results are associated with the use of images, which represent information in a compact way, of easier comprehension.