Environmental Impact Assessment Tools

An Environmental Impact Assessment (EIA), a statement of the environmental consequences of specific projects like building construction or the operation of a factory, has become an increasingly common and useful method for determining the environmental appropriateness of a project. Although formats vary somewhat from organization to organization, increased government regulation demanding the completion of EIAs and establishing certain requirements for the assessments has generated a series of best practices and tools common to the most effective EIAs.

Matrix Method

• Matrix methods, usually based on the "Leopold matrix," organize project actions and impacted areas into a matrix (spreadsheet) for simple visual communication of the project's impacts. Potentially impacted areas, such as "flora," "water quality" or "prevalence of respiratory disease," are organized into the first column of the matrix, while project actions, like "ground clearing" or "crane operation," are placed in the heading row. The matrix is then filled out with the expected impact of each action on each area in the cell where the two meet. For instance, a contractor would fill out the impact of an action like ground clearing by filling out the column underneath the heading, referencing each impact to a specific area and the level of impact. Ground clearing could have a high impact on local flora, but negligible impact on the prevalence of respiratory diseases. The result is a visual format that quickly demonstrates the actions with the highest impact (by the number of cells filled in under each heading) and the most impacted parameters (by the number of cells filled out in the row).

Batelle Method

• The Batelle method is a more quantitative approach to EIAs. Environmental impacts, such as "water pollution" or "noise pollution," are organized into categories. Each impact is then given a set of indicators that also serves to determine the relative importance of the impact in the assessment. If water pollution is a particular concern for the study, for example, it would have a number of indicators like dissolved oxygen, microbiological pollution or mercury concentration. Each of these indicators is then given a numerical value corresponding to its importance, essentially a unit of environmental quality determined by each indicator. The assessment then determines the increase or decrease in each of these values caused by the project, yielding a baseline numerical value of environmental quality before the project and a new numerical value of environmental quality after the project to assess its environmental impact.

Checklists

• Often used for smaller or more urgent projects, checklist formats are abbreviated EIAs that serve to either guide a larger EIA or to quickly establish that certain minimum requirements have been met before the project proceeds. Checklists can function as a quick-permitting option, creating a list of the most important environmental best practices relevant to the specific project and making approval of the project conditional on its meeting each of the criteria and, thus, presumably having a minimal environmental impact. Checklists, however, cannot anticipate the complexities of larger projects and are seldom used for projects that involve a large-scale change in the environment.

Software

• Given the complexity of ecological and social parameters considered by most EIAs, many EIA authors choose to use software that automatically assesses the impact of certain actions conducted on certain areas. This software includes environmental settings, such as "wetlands," "forests" or "urban areas," and the users input a set of actions to be carried out in the area, like "demolition," "paving" or "construction." The software then automatically estimates the impact on the user-selected environment of the actions the user chooses, generating a full EIA of the project. Software solutions, however, are often unable to anticipate the very specific particularities of each situation.