Naval Facilities Engineering and Expeditionary Warfare Center (NAVFAC EXWC) proposes to construct and operate two wave energy test site (WETS) berths for testing offshore wave energy conversion (WEC) devices in waters off the north coast of Mokapu Peninsula at MCB Hawaii. The “deep-water” WETS berths would be located in approximately 197 feet (ft) (60 meters [m]) and 262 ft (80 m) of water, approximately 6,500 ft (2 kilometers [km]) and 8,200 ft (2.5 km), offshore of MCB Hawaii, respectively. The Proposed Action includes installation and operation of two trunk power and communications transmission cables, in-water scientific data gathering equipment, and associated shoreside electrical transmission and monitoring equipment. Construction of the new berths would occur within a one-year period, with the first deep-water WEC device installed in 2014. Subsequent WEC devices would be installed when another device developer is ready to begin testing, but no earlier than one month after installation of the first device. Timing of WETS decommissioning would be based on WEC device test activity and funding. It is currently planned for the 2016 timeframe, but use of the site could extend beyond that time.
Three alternatives were analyzed in the EA: 1) Surface-Laid Cable Alternative (Preferred), in which the power and communications cables would be landed on shore in the vicinity of an existing subsea transmission cable and routed to termination points with the MCB Hawaii electrical grid and monitoring equipment; 2) Horizontal Directional Drilled (HDD) Alternative, which is the same as the Proposed Action except the onshore portion of the transmission cable would be routed below grade through an approximately 2,000-ft (609-m) long subsurface bore hole drilled from Building 614 to an offshore outlet point in approximately 33 ft (10 m) of water and 3) No Action, in which no construction would occur and no deep-water WETS berths would be established.
The Proposed Action would not result in significant impacts to the following resources: climate, air quality, geology, soils, shoreline geomorphology, oceanographic conditions, water quality, natural hazards, marine biological resources, terrestrial biological resources, land and water use compatibility, cultural resources, recreation, infrastructure, public safety and visual resources. The Proposed Action would not create environmental health and safety risks that could disproportionately impact children or minority and low-income populations. The Proposed Action is listed among the de minimis activities agreed upon between the Navy and the State of Hawaii Coastal Zone Management (CZM) Program, and is not subject to further review by the State CZM Program. The State CZM office was advised on 11 July 2013 of the Navy’s usage of the De Minimis Activity List and the preparation of this EA; it acknowledged receipt of the Navy’s notification on 12 July 2013. The Navy found that the Proposed Action may affect, but is not likely to adversely affect Endangered Species Act (ESA) protected marine mammals and sea turtles, ESA proposed listed corals, or proposed Hawaiian monk seal critical habitat. The Navy conducted informal consultation with National Oceanic and Atmospheric Administration National Marine Fisheries Service (NOAA Fisheries) under Section 7 of the ESA; NOAA Fisheries concurred with the Navy’s determination. The Navy conducted informal consultation on Essential Fish Habitat (EFH) with NOAA Fisheries and found that the Proposed Action may have adverse effects on EFH, but effects would be minimal and insignificant. The project area contains two historic properties: Mokapu Burial Area (Site 1017) is listed on the National Register of Historic Places (NRHP) and Building 614 is eligible for NRHP listing. MCB Hawaii determined that the Proposed Action would result in no adverse effect to historic properties and consulted with State Historic Preservation Officer (SHPO) under Section 106 of the National Historic Preservation Act. SHPO did not object to this determination and its concurrence is assumed due to lack of objection within the 30-day period following receipt of the MCB Hawaii consultation letter dated 29 March 2013. The State Office of Hawaiian Affairs concurred with MCB Hawaii’s no adverse effect determination in an electronic mail message dated 19 December 2013.
Based on the information gathered and analysis conducted during the preparation of this EA, the Navy has determined that the Proposed Action will have no significant impacts on the quality of the human environment.