A National Park Service official says a wind project proposed for a Skamania County site just outside the Columbia River Gorge National Scenic Area would intrude on the experiences of people traveling two national historic trails.

Both the Lewis and Clark National Historic Trail and the Oregon Pioneer Historic Trail pass through the Gorge, and both also pass within five miles of where turbines would rise at the Whistling Ridge Wind Project, said Rory D. Westberg, the Park Service's deputy regional director for planning and resource management.

"Historic travelers on these trails used both the river for downstream transportation and adjacent lands for eastward travel," Westberg noted in a letter to the Bonneville Power Administration. "When Congress designated these trails, it also authorized auto tour routes along Interstate 84 and Washington Route 14. The viewshed from both the river and auto tour routes is a critical part of the visitor experience."

The BPA is working with the Washington Energy Facility Site Evaluation Council, a state agency, to prepare a joint environmental impact statement for the 75-megawatt project. SDS Lumber Co. of Bingen has applied to build 50 turbines atop a ridgeline on industrial timberland it owns near Underwood.

Westberg noted that, in addition to designating historic trails to mark the routes of the Lewis and Clark Expedition and the Oregon Trail, Congress also protected the Gorge itself by designating it a national scenic area in 1986.

"These three national resources are independently significant, but the close proximity of all three to each other creates a unique recreational opportunity for visitors to the region," he wrote. "It is important for the (Park Service) to ensure that the scenic and historic values of these areas are preserved from gross alteration of the landscape and viewshed by large-scale industrial development."

Westberg took issue with what he called "dated" assumptions in SDS Lumber's application regarding how visible the 426-foot-high turbines would be and how the public would react to them.

Towers are now taller than 22 years ago, when viewer perceptions were first measured, and far more numerous on the landscape, he said.

"Man-made structures, especially when movement of a structure acts as an additional point of focus, depreciate the scenic and historical qualities that originally warranted national protection," Westberg wrote. "We are concerned with the cumulative impacts to the viewshed resulting from numerous uniform wind turbines extending beyond the horizon line within an open, natural landscape."

At a minimum, he said, reviewing agencies should remove the southernmost string of turbines from further consideration to reduce the negative impacts.

The Park Service is the second federal agency to submit formal comments warning about the visual impacts of the project.

Dan Harkenrider, Forest Service manager of the national scenic area, told the state energy facility siting agency recently that the southernmost towers would be visible from several viewpoints inside the scenic area.

He warned of "the risk of significant impacts to protected scenic resources if the proposed energy project is built as currently planned."

SDS President Jason Spadaro has argued that because the scenic area act does not provide for buffers, the Forest Service has no standing to address scenic impacts resulting from developments outside the scenic area boundary.