The scale of Libby Dam is clear at a distance. Jake Williams, its natural resource specialist, is well-versed in its specifics.

“The length of the dam at its crest is over 3,000 feet,” he explained in his dam-side office. The 422-foot-high concrete wall, he continued, is “56 feet wide, and we’re 310 feet wide at the base.” That girth enables it to hold back the 90-mile-long Lake Koocanusa, which extends north into Canada and flows back into the Kootenai River below the dam — cranking out power for tens of thousands of homes along the way.

Facing this mass, it’s easy to miss a subtler detail: there are almost no right angles.

Nearly every juncture in the dam’s design, from the Treaty Tower at its center to the knee-high lamps in the Visitor Center parking lot, has been beveled or tilted off 90 degrees — a mental trick, Williams explained, from the dam’s architect, Paul Thiry.

Thiry’s modernist, off-kilter angles, like the wood-paneled interior of Treaty Tower and its photos of visits from Presidents Nixon and Ford during construction, are reminders that Libby is a product of a different era. Completed in 1972 and dedicated in 1975, the dam was part of a larger, bi-national effort to regulate the Columbia River system.

Its operations have since been adapted to meet greater concern for the Kootenai River’s ecology, periodically sending water down its spillway to meet the needs of fish. And the United States and Canada are about to start re-negotiating the Columbia River Treaty that provided for Libby.

While times have changed, Williams said, Libby still brings plenty of benefits to Northwest Montana.

“It’s a jewel in this region of the state,” he said, explaining that Koocanusa offers locals and visitors superb fishing, boating, wildlife-watching and even disc golfing.

“We have outstanding recreation opportunities, [and] we’re one of the few dams left in the country that still provide dam tours on a daily basis...There’s just a lot of moving parts here that makes this place very unique, very inspiring to be a part of.”

To find out more about Libby Dam and visitation, visit http://www.nws.usace.army.mil/Missions/Civil-Works/Locks-and-Dams/Libby-Dam/Recreation/.

Reporter Patrick Reilly can be reached at preilly@dailyinterlake.com, or at 758-4407.