State Environmental Policy Act.
The State Environmental Policy Act (SEPA) establishes a review process for state and local governments to identify environmental impacts that may result from governmental decisions, such as the issuance of permits or the adoption of land use plans.  The SEPA environmental review process involves a project proponent or the lead agency completing an environmental checklist to identify and evaluate probable environmental impacts.  If an initial review of the checklist and supporting documents result in a determination that the government decision has a probable significant adverse environmental impact, known as a threshold determination, the proposal must undergo a more comprehensive environmental analysis in the form of an environmental impact statement (EIS).  If the SEPA review process identifies significant adverse environmental impacts, the lead agency may deny a government decision or may require mitigation for identified environmental impacts.

The State Environmental Policy Act addresses both project and nonproject actions.  Project actions involve an agency decision on a specific project and include construction, alteration of public buildings, and infrastructure.  Nonproject actions are governmental actions involving decisions about policies, plans, or programs.

Under SEPA, certain project and nonproject actions are categorically exempted from the requirements of SEPA.  Examples of categorically exempt nonproject actions include certain amendments to development regulations and certain amendments to technical codes.  An example of a categorical exemption is an action relating to infill development in urban growth areas.

Decisions pertaining to the development or extension of a trail or path are categorically exempt from SEPA if the proposed new trail or path, or extension to an existing trail or path, meets the following conditions:

• has a surface area of 10 acres or less;
• is located on an inactive railroad right-of-way designated for interim trail use; and
• is not located in a designated critical area under the Growth Management Act.

Improvements covered under this exemption include utilities and support infrastructure for trails and paths, including:

• street crossings;
• lighting;
• signage; and
• parking facilities otherwise exempt under SEPA.

Unrelated infrastructure improvements are not covered under this exemption.