5.4.2 Environmental Documentation Types
All federal actions and state transportation projects require documentation that details TxDOT's review of potential environmental impacts. The three classes of actions that prescribe the level of documentation required in the environmental process are described below:
- Environmental Impact Statement (EIS). An EIS is prepared for a project that has significant social, economic, or environmental impacts. An EIS is very prescriptive in process and requires extensive stakeholder and public feedback. An EIS often takes the longest amount of time to complete of the three documentation types.
- Environmental Assessment (EA). An EA is necessary for a project that has not clearly established the significance of potential impacts. Occasionally, an EA is initiated for a project that results in a finding of significant social, economic, and environmental impacts, which then requires preparing an EIS. When a project has a Finding of No Significant Impact (FONSI), the EA is useful to share those findings with stakeholders and the public. An EA is often completed in a shorter timeframe than an EIS; however, longer than a Categorical Exclusion since it summarizes the technical reports that came to the determination of a FONSI.
- Categorical Exclusion (CE). A CE determination is required for projects which do not individually or cumulatively have significant environmental effects and are excluded from the requirement to prepare an EIS. A CE determination typically is the shortest of the three documentation types since only technical reports supporting that determination are needed.
Detailed information on type of environmental studies and documentation are included in TxDOT’s
Environmental Guide – Volume 1 Process
document.