Looking to Lake Dorothy for more power

Posted: Sunday, January 13, 2002

A single 4-inch Dolly Varden trout could block development of new hydroelectric power for Alaska's capital city.

The proposed project would tap Lake Dorothy, a 3-mile-long, 560-foot-deep, glacier-fed lake on the east side of Taku Inlet.

"We are at a point where Juneau's energy demand is equal to our firm hydroelectric energy supply in a dry year," Corry V. Hildenbrand of Alaska Electric Light & Power told the Juneau Chamber of Commerce on Friday. "Firm" refers to the minimum expected megawatts generated during a year with the least rainfall.

"Lake Dorothy would help provide low and stable electric rates, which would help provide an attractive business environment for Juneau," said Hildenbrand, who is both president of Lake Dorothy Hydroelectric Inc. and vice president of energy development at AEL&P.

Lake Dorothy, which sits at an elevation of 2,400 feet, is 25 miles closer to downtown Juneau than is the Snettisham project, which now supplies most of the borough's electricity.

In addition to its handy nearness, said David Stone, vice president of consumer affairs for AEL&P, the $30 million Lake Dorothy project has two things going for it:

• A submarine cable laid in 1999 has sufficient capacity to transport any energy it would produce.

• The east terminal crossing of the cable is only three miles from where Dorothy Creek spills into Taku Inlet, the site where the proposed power house would be built.

However, the monkey wrench for the project could be the Dolly Varden found near the mouth of Dorothy Creek during an environmental impact survey, Hildenbrand said.

The Lake Dorothy project has been talked about for 60 years.

As seen from the air, Lake Dorothy and two other lakes below it resemble a stepped fountain. Dorothy pours into Lieuy Lake, which pours into Bart Lake, which discharges into Dorothy Creek. With gorges and waterfalls galore, it is "extremely rough terrain," Hildenbrand said, best accessed by using a penstock rather than a dam approach.

A penstock is a tube or trough for carrying water and controlling its flow. A tunnel would be drilled to tap Lake Dorothy 100 feet below its waterline, and a "faucet" installed to control the water flow to Lieuy. Dorothy would be considered a reservoir, used as needed.

That would be the last phase of the project. Phase I would be to build an access road to Bart Lake and tapping it. Phase I could generate a maximum of 14.3 megawatts of power.

Phase II would tap Dorothy and connect it to Lieuy and Bart. That would generate an output of 30.3 mw, which Hildenbrand calls "a nice resource for the future of Juneau."

The first preliminary permit for the project was received in 1996. Lake Dorothy Hydroelectric Inc. filed an environmental impact statement in June 2001, only to find that additional studies were required. In October, LDHI met with resource agencies to discuss issues related to fisheries and water resources. If all goes well, a final permit could be issued in September 2003, Hildenbrand said.

But then there's that trout. Dorothy Lake has been stocked with eastern brook trout, a non-native species. There is some concern that draining water from Dorothy during spawning months would endanger the brookies' habitat, Hildenbrand said.

The U.S. Forest Service is not concerned with preserving this non-native species, and might allow LDHI to provide fisheries mitigation in another location to make up for its impact here. However, the agency is concerned about the native Dolly.

"If we have to preserve the habitat for (Dolly Varden) trout, we don't have a project," Hildenbrand said.

But Pete Griffin, head ranger for the Juneau Ranger District with the Forest Service, put a slightly different spin on the situation: "From our standpoint, it's a good project, and the folks in charge of the planning have been very responsive to our needs.

"I don't think there will be a problem (with the Dolly Varden), but we need to assess the difference between the habitat that is there now and what will be there when the plant is operating," Griffin said.

If LDHI gets construction permits, it would prepare the site in 2003, constructing an access corridor to Bart Lake, and taking rock samples where tunnels would be sited. In 2004, it would clear the transmission right of way from the mouth of Dorothy Creek to the east terminal of Snettisham Lake. In 2005, penstock and tunnels would be constructed. The project would go online in November 2006, making 2007 the first full year of operation.

The Lake Dorothy substation would be unmanned, visited by maintenance crews twice a week.

Ann Chandonnet can be reached at achandonnet@juneauempire.com.



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