Two federal agencies are weighing in with detailed concerns about the impacts from increasing the number of EA-18G Growler aircraft on Whidbey Island.

The agencies are also questioning the adequacy of the Navy’s study of these impacts.

The National Park Service even offered to acquire the Navy’s Outlying Field Coupeville landing field in Central Whidbey to protect the soundscape of Ebey’s Landing National Historical Reserve from the aircraft.

The Environmental Protection Agency and the Department of Interior — which is the umbrella agency for the National Park Service — submitted comments this year on the Navy’s draft Environmental Impact Statement, or EIS, for the addition of 35 or 36 Growlers at Naval Air Station Whidbey Island.

The comment period has since closed.

The EPA rated the EIS as “environmental concerns with insufficient information,” according to the the letter from R. David Allnut, director of the EPA’s Office of Environmental Review and Assessment.

“The DEIS does not contain sufficient information to fully assess the environmental impacts that should be avoided to fully protect the environment and nearby communities,” the letter states.

A press release for the anti-noise group Citizens of Ebey’s Reserve states that the EPA’s concerns mirror those that the group has been expressing all along.

“COER’s noise experts indicate that the noise modeling used by the Navy needs on-site validation, which unsurprisingly is exactly what the EPA has noted,” Robert Wilbur of COER said. “For more than four years COER has asked the Navy to do real noise monitoring of Growler flights rather than just computer modeling. Those requests were ignored, so COER paid for limited on-ground testing in high-populous high-noise areas. The results were alarming.”

Ted Brown, Fleet Forces public affairs officer, said Navy officials are aware of the comments from the federal agencies. He said staff is busy going through and cataloging more than 4,300 comments made on the draft EIS and it would be inappropriate to speculate on how the Navy will address any specific concerns.

While the draft EIS states that there are no conclusive links between Growler noise and health problems, the EPA offered a list of studies on health effects and wildlife impacts and urged the Navy to update the information in the final EIS. Similarly, the state Department of Health concluded in comments for the draft EIS that the evidence of health impacts of noise similar to Growlers is convincing.

The EPA — and the state Department of Health — recommended that the Navy conduct a health assessment on Whidbey residents affected by Growlers noise.

Both the EPA and the Department of Interior requested verification of the computer modeling the Navy used to predict noise levels. The EPA recommended that the Navy establish a monitoring program to verify that the actual noise impacts are similar to what’s projected in the EIS.

The Park Service conducted its own acoustic monitoring in Ebey’s Landing National Historical Reserve in Central Whidbey and found that the modeling in the draft EIS “significantly under represented” the noise levels the Park Service found in real-life conditions.

The Department of the Interior also requested the Navy conduct additional noise monitoring. The comment letter states that Growlers should be outfitted with chevrons or other technology that dampens the noise and the Navy should look at expediting the implementation of software that automates some pilot controls for landing, which would translate to less need for practice.

The comment letter from the Department of the Interior goes into much greater detail than the comments from the EPA. Much of the commentary is focused on Ebey’s Landing National Historical Reserve, which was the first such reserve created in the nation. The federal law establishing the reserve acknowledged the national historical significance of the area and charged the Department of the Interior to work with state and local officials to protect it.

The comment letter concluded that all of the alternatives proposed in the draft EIS “negatively impact the features of the rural community that the Reserve has been congressionally designated to protect.”

The Navy uses Outlying Field Coupeville — which is on the edge of the reserve — for Growler aircraft carrier landing practice. The draft EIS outlines alternatives based on the number of practices at OLF Coupeville as compared to the Ault Field base, as well as the types of squadrons the new Growlers will go to.

The letter from the Department of the Interior states that “existing noise caused by military overflights already cause significant impacts on a regular basis” and that increased Growlers will “significantly impact soundscapes throughout the Reserve.”

The purchase by the Park Service of the 468 acres that make up OLF Coupeville “would improve maintenance of the rural landscape and historic scene, and protect open space for plant and animal habitat,” the comment letter states.

The letter states that an increase in Growler operations would have economic consequences for Central Whidbey. The reserve generated millions of dollars each year for the local economy through tourism, and Growler noise “harms the visitor experience,” according to the letter.

The Department of the Interior cites a lack of evidence to support claims in the draft EIS that the increase in Growler operations is unlikely to affect wildlife and that birds won’t be harmed because they are already habituated to the noise. The department expressed concern especially with migratory birds, which have special protections under federal law.

While the draft EIS states that the Navy is still evaluating potential impacts to historic architecture resources, the Department of the Interior points out that, under federal law, the work should have been done before the draft EIS was released for comment.

The department is also concerned with the possibility of groundwater contamination associated with the use of foam to suppress aircraft fire at OLF Coupeville.

The letter says that the Park Service realizes the importance of Growlers to national defense and that some noise impacts are unavoidable.

“Therefore, we request the Navy work with NPS to develop a long-term action plan for collaboration and coordination in order to facilitate better communication and local interaction between agencies,” the letter states.