Introduction

The Department of the Air Force (DAF) has published a Final Supplemental Environmental Impact Statement (SEIS), pursuant to the National Environmental Policy Act (NEPA) of 1969, for the proposed Tinian Divert Infrastructure Improvements. The Final SEIS takes into consideration substantive comments that were provided during the Draft SEIS public review period in 2019. DAF published the Draft SEIS for public review on May 17, 2019; the public review period for the Draft SEIS ended on July 1, 2019.

The Proposed Action includes the construction of a fuel pipeline and associated support facilities, and improvements to certain existing roadways on the island of Tinian in the Commonwealth of the Northern Mariana Islands (CNMI).

This page is a guide to NEPA and the SEIS process, and the Tinian Divert Infrastructure Improvements proposal.

About NEPA and EISs

NEPA was enacted to address concerns about federal actions and their effects on the environment. An Environmental Impact Statement (EIS) is the most detailed analysis prescribed by regulations implementing NEPA. An SEIS is prepared after an EIS when substantial changes are made to a proposed action, there are significant new circumstances or information relevant to environmental concerns, or the purposes of NEPA will be furthered by completion of the SEIS. An SEIS is a public document and public involvement is a vital component of the NEPA process.

Background of the DAF Tinian Divert Project

In September 2016, the DAF completed the Final EIS for Divert Activities and Exercises. The Record of Decision (ROD) was signed December 7, 2016, which announced the DAF decision to select the Modified Tinian Alternative North Option as a future Divert location (see Figure 1). After the ROD, the DAF conducted further evaluation of the fuel requirement and associated infrastructure, and of the existing surface roadway networks on Tinian. The DAF now proposes to construct a fuel pipeline to transport fuel from the seaport to the airport, rather than using fuel trucks for fuel transfer. In addition, the DAF also proposes to improve certain existing roads between the seaport and airport that would be used to support Divert-related projects. For more information on the 2016 Divert Activities and Exercises EIS, visit the Archive page on this website.

Proposed Actions and Alternatives

The SEIS addresses two Proposed Actions. The first Proposed Action is to construct and operate a fuel pipeline from the Tinian seaport to Tinian International Airport, to include a booster pump house, boom storage building, and necessary utility connections at the Tinian seaport. The second Proposed Action also includes the improvement of certain existing roads between the seaport and airport that would be used to support Divert-related projects. Specifically, the Proposed Actions are:

• Fuel Pipeline and Seaport Support Infrastructure: The pipeline would be constructed underground within a 20 foot easement and along existing right-of-ways, to the extent practicable. DAF is considering two pipeline routes from the seaport to the airport; the East route and the West route. DAF has identified the East route as the preferred alternative for the pipeline. To support pipeline operations, a booster pump house, boom storage building, and associated infrastructure would be constructed at the Tinian seaport in place of the two seaport fuel storage tanks proposed in the original EIS.

• Roadway Improvements: Roadway improvements are proposed on Divert-related transportation routes that were analyzed in the original EIS, and would include, where necessary, removing and replacing the existing deteriorated asphalt cap of the roadway.

For more information on NEPA, the SEIS process, and the Tinian Divert Infrastructure Improvements proposal, please see the materials on the Documents page of this website.