The Blue Lake dam spilled for the first time this weekend, several months ahead of schedule. (Photo courtesy of Lance Ewers).

The Blue Lake dam spilled for the first time this weekend, several months ahead of schedule. (Photo courtesy of Lance Ewers).

Sitka’s Blue Lake hydro project reached another milestone this weekend, as water began spilling over the lip of the Blue Lake Dam.

And “spill” probably isn’t the right word. With the dam now some 83 feet higher, the result is a full-fledged waterfall.

Project Manager Dean Orbison said it means the project is well and truly done — and the dam is doing its job.

“It means that the dam did not tip over when we put water behind it, and that’s what it was designed to not do,” he said. “It’s holding the reservoir back just exactly like we designed it to do.”

What’s surprising is the timing. Water spilling over the dam means the reservoir is completely full, covering an additional 362 acres of forest land. That’s several months ahead of the best-case scenario predicted by project planners. The reservoir wasn’t expected to fill until this October or November, at the earliest. But a warm winter and spring has meant a quick snow melt, lower electricity use — and high water levels.

Orbison compared the reservoir to a fuel tank — and right now, Sitka’s tank is full to overflowing. Any water that spills over the dam isn’t flowing through the turbines in the Blue Lake power house, and isn’t being converted into electricity.

So if you have a project that requires a lot of electricity, well, now’s a good time for it, Orbison said.

“The key thing everyone should know is that they should use electricity so that we can pay for the whole thing,” Orbison said, laughing. “Because that’s how it gets paid for, with revenue from selling electricity.”