The glimpse of the electrical conduit inside one of the Green Lake dam tunnels. The city has repaired a leak that shut down the hydro plant for a little over a week. (Photo courtesy of CBS Electric Department)

Sitka’s Green Lake hydro plant is back in business, after the city repaired a leak in the penstock.

The dam has been offline since June 19th. Staff discovered a leak in a electrical conduit that runs down the penstock tunnel, which delivers water from the dam to the powerhouse. Electric Department personnel repaired the leak on the 26th and returned the hydro plant to full service on the 28th.

While Green Lake was down, the Blue Lake hydro plant supplied all of Sitka’s energy needs. The city did not have to tap diesel fuel sources. The Electric Department was also able to test a 37-year-old “spare” transformer at Green Lake, and determined it was still operational.

This is the second time in the past calendar year the Green Lake hydro plant has been closed for mechanical failure.

In a press release issued yesterday, city utility director Bryan Bertacchi thanked citizens for their patience and support. He’s also encouraging the city invest in an alternative source of potable water, in the event that the Blue Lake penstock is ever shut down for a similar repair — or even routine maintenance. At present, all Sitka’s drinking water is supplied by Blue Lake.

Bertacchi says that the Blue Lake penstock will need to be shut down every five years for cleaning, at which time Sitka will need a back-up water supply. To that end, the city has requested $5 million dollars in federal funding to develop an alternative source of water. The Assembly approved that project among a list of “shovel ready” projects for consideration by the Trump administration.