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Quick and Dirty Guide to EIA

What is EIA?

Environmental Impact Assessment is a tool used for decision making regarding projects, developments and programmes such as incinerators, airport runways, pig rearing and peat extraction. EIA is intended to identify the Environmental, Social and Economic impacts of a proposed development prior to decision making.

This means that it is easy to identify;

  1. The most environmentaly suitable option at an early stage.
  2. The Best Practicable Environmental Option.
  3. Alternative processes.
The project managers can then address these problems in order to avoid or minimise environmental impacts in conjunction with their project planning. This results in the likelyhood of the project planning stages running smoother

The Environmental Assessment is carried out by the Developer although the task is often carried out by Environmental Consultants. Environmental Assessment is carried out in order to produce an Environmental Statement. The Environmental Statement must include:

  • A description of the project: location, design, scale, size etc.
  • Description of significant effects.
  • Mitigating Measures
  • A Non-Technical summary.
There are two steps in EIA. The two stages are
  • Preliminary Assessment: Carried out in the early stages of planning
  • Detailed Assessment: Carried out during project planning until the project plan is completed and are reported formally as an Environmental Statement

What is Scoping?

Scoping is used to identify the key issues of concern at an early stage in the planning process. Scoping should be carried out at an early stage in order to aid site selection and identify any possible alternatives. The scoping process should involve all interested parties such as the proponent and planning or environmental agencies and members of the public. The results of scoping will form determine the scope, depth and terms of reference to be addressed within the Environmental Statement.

Why carry out Scoping?

  • To identify the key issues and concerns of the interested parties.
  • Who is concerned?
  • What are their concerns?
  • Why are they concerned?
  • What is the threshold of concern where change becomes unacceptable?
When ineffective scoping occurs delays are caused by additional time being required to assess unidentified impacts.

Once the site for development has been selected the scoping angle changes. There will be a decrease in the number of issues and an increase in attention to detail . Scoping should be an ongoing exercise throughout the course of the project.



This is used to decide whether an Environmental Assessment is required. There are two lists, referred to as schedules.

Schedule 1 - Environmental Assessments are required in every case. Schedule 1 projects range from "an integrated works for the initial melting of cast-iron and steel", to "a thermal power station or other combustion installation with a heat output of 300 MW or more."

Schedule 2 - Environmental Assessments are required if the project is likely to give rise to significant environmental effects by virtue of factors of their nature, size or location. The list of Schedule 2 projects is greater than that of schedule 1. It covers projects from "a holiday village" to "peat extraction" and "pig rearing" to "a shipyard".

Screening is a comprehensive and clear method of decision making. It is practical, quick and easy to use.


This includes both alternative sites and alternative techniques. This search must be genuine, well documented and carried out before a choice has been made. It is usually the case that alternative sites are available as well as practical although this is not always the case. Some projects are site specific such as mining. The extraction can only occur were the mineral is sited. In such cases an EIS is pointless although other measures such as scale, mitigating measures and traffic management are addressed.


Mitigating Measures

This reviews the action taken to prevent, avoid or minimise the actual or potential adverse effects of a project. The measure could include the abandoning or modifying of a proposal, substitution of techniques using BATNEEC (Best Available Technology Not Entailing Excessive Costs). This would include the various pollution abatement techniques that would be required to reduce emissions to the legal limits.


If the uncertainties are great, with the possibility of grave consequences and no mitigating measures then the development plan is rejected. If there are uncertainties that might me reduced by further studies then the applicationis deferred until further studies are carried out.

Environmental Statements

The EIA is the process required to produce the Environmental Statement. The EIS is a comprehensive document that reports the findings of the EIA. This is the final stage of the EIA process and is now often required by law before a new project can proceed.

A typical EIS can be broken down into three parts with different levels of detail:

Volume 1 - a comprehensive and concise document drawing together all relevant information regarding the project; Non-Technical Summary (NTS) - a brief report of volume one in non-technical language so that it can easily be understood by the public;

Volume 2 - a volume which contains detailed assessment of the significant environmental effects. (This is not necessary if there are no significant effects either before or after mitigation).

Source: Adopted from "What is EIA?" by Richard Hamilton
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