Background

The NEPA decision-making process requires the consideration of direct, indirect, and cumulative impacts. Indirect effects are generally defined as those "which are caused by the action and are later in time or farther removed in distance, but are still reasonably foreseeable." Cumulative impacts are defined as "the impacts on the environment, which result from the incremental impact of the action when added to other past, present and reasonably foreseeable future actions regardless of what agency (Federal or non-Federal) or person undertakes such other actions." (40 CFR 1508.7 and 1508.8)

The appropriate identification, analysis, and documentation of indirect impacts and cumulative impacts present many challenges during the NEPA decision-making process. Indirect and cumulative impacts include less obvious environmental consequences than do direct impacts. In addition, analysis of indirect and cumulative impacts requires forecasting uncertain but reasonably foreseeable events. Further complexities arise when determining the appropriate and reasonable project scope, temporal and resource boundaries, and analytical methodologies.

Because of the more diffuse nature of indirect and cumulative impacts, analyzing them can be a source of conflict among agencies and a source of delay in the environmental review of transportation projects. Uncertainties and conflict often relate to several issues: the appropriate scope of analysis in terms of time and geographic area; appropriate methodologies and level of detail; the reasonableness or practicality of obtaining information that is not readily available; and the appropriate role of the transportation agency with regard to mitigation.

Work Group Activities

To guide its efforts, the Indirect and Cumulative Impacts Work Group developed a work plan that describes the complexities and challenges associated with these issues, and includes recommendations for activities to address the challenges.

The first activities of the Work Group focused on developing a baseline of information on the current state of the practice, obstacles, and opportunities, based on a review of Environmental Impact Statements and discussions with staff at federal and state transportation and resource agencies. The Work Group developed a baseline assessment report, which is under review by the Work Group and Task Force.

Components of the report include:

• A compilation of laws, regulations, and Executive Orders and their relation to indirect and cumulative impacts;
• A summary of case law relating to indirect and cumulative impacts;
• An annotated bibliography of guidance documents relating to indirect and cumulative impacts;
• A compilation of training programs on indirect and cumulative impacts; and
• Case studies of notable practices related to indirect and cumulative impacts.

Indirect and Cumulative Impacts, Work Group Draft Baseline Report - March 15, 2005