The National Environmental Policy Act (NEPA) requires federal agencies to evaluate the environmental, socioeconomic, and other effects of proposed actions and alternative actions. The NEPA process also encourages and facilitates the involvement of interested parties in the analysis of projects and provides opportunities for public review and comment on their evaluations.
Section 102 in Title I of NEPA requires federal agencies to incorporate environmental considerations in their planning and decision-making through a systematic interdisciplinary approach. Specifically, all federal agencies are to prepare detailed statements assessing the environmental impact of and alternatives to major federal actions significantly affecting the environment. These statements are commonly referred to as Environmental Impact Statements (EIS) and Environmental Assessments (EA).
The BLM will complete a site-specific environmental review in accordance with NEPA of all solar energy projects in designated leasing areas (DLAs) and on other BLM-administered lands prior to issuing a project authorization. As part of the Solar PEIS, the BLM conducted a thorough environmental review of the SEZs (now DLAs) so that future reviews of projects within them can tier to the existing NEPA analysis, thereby limiting the required scope for additional project-specific NEPA analyses.
Tiering refers to using the coverage of general matters in a broader NEPA document, such as the Solar PEIS, in a subsequent, narrower NEPA document (40 CFR 1508.1[ff]) This allows the tiered NEPA document to narrow the analysis and concentrate solely on the issues not already addressed. Tiering is appropriate when the analysis for the proposed action will be a more site-specific or project-specific refinement or extension of the existing NEPA document. The SEZ analyses in the Solar PEIS identified required general and SEZ-specific design features to address many resource conflicts, thus new projects in the 6-state study area would likely tier to the Solar PEIS. However, it is expected that certain resource areas such as groundwater and surface hydrology will typically require additional NEPA analysis to further understand potential impacts.