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Targeting a troubled Tahoe tributary

Courtesy ImageBlackwood Creek, which carries large amounts of sediment into Lake Tahoe, flows under a concrete bridge built during an earlier phase of restoration work on Blackwood Canyon.
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A rugged canyon that funnels up to the skyscraping crags of Barker Pass and Twin Peaks has become one of Lake Tahoe’s biggest water clarity problems.

But an enormous federal restoration effort seeks to repair the troubled watershed of Blackwood Canyon.

Blackwood Creek, the lifeblood to the 11.2-square-mile watershed three miles south of Tahoe City, deposits the most sediment, for a creek of its size, in the Lake Tahoe Basin. The sediment can contain unwanted nitrogen and phosphorus, according to the Truckee River Watershed Council’s Lisa Wallace.



“These nutrients feed lake algae, and diminish lake clarity,” said Rex Norman, spokesman for the Tahoe arm of the U.S. Forest Service, in a press release.

Blackwood Creek generates approximately 30 percent of all streambank erosion in the Lake Tahoe Basin, according to documents provided by the Lake Tahoe Basin Management Unit. The other largest offender is the Upper Truckee watershed in South Lake Tahoe.



The creek has lost its ability as a filter, Norman said, in part because of past unmanaged recreational use. Today’s snowmobilers and offroaders, if they follow Forest Service rules, do not impact the stream, he said.

It’s the past’s unmanaged gravel mining, logging and grazing, he said, that have damaged the stream’s natural filtering effect. The stream channel was even changed to suit some past users, according to Norman.

The creek is responsible for depositing 844 tons of sediment per year into Tahoe, 200 tons being directly related to eroded stream banks, according to Forest Service documents.

Now, Norman’s agency, the Lake Tahoe Basin Management Unit, has secured millions of dollars in funding to begin phase three of the creek restoration, which could start as early as this summer and run through 2010.

The project is the largest environmental restoration effort the Forest Service has tackled in the Tahoe Basin, said Norman.

The first phase began in 2001 and included replacing an decades-old, man-made fish ladder that was more a hindrance than help for trout that swim upstream, said Craig Oehrli, hydrologist on the project.

The second phase was completed in 2006, installing a new 125-foot bridge where an old concrete ramp used to pass over the creek. Beneath the ramp was a corrugated steel culvert that caused the water to flow like it was shot from a “fire hose,” said Norman in a 2005 essay, “creating more erosive force just downstream.”

“The old bridge and culvert were very damaging to the creek,” he said in an e-mail Friday.

The funding comes in large part from the Southern Nevada Public Land Management Act, which became law in 1998. It allows Nevada’s Bureau of Land Management to sell public land and use the revenue for specified purposes including Lake Tahoe restoration projects, according to the land management agency’s Web site.

Other organizations in the area are keeping a close eye on the project.

“One of the things that is important is we are spending a lot of money on these restoration projects,” Wallace said.

One way to save money, according to the executive director of the Truckee River Watershed Council, is to capitalize on the discoveries the Forest Service makes while restoring the Blackwood area. The methods they use can then be applied to similar canyons in Truckee.

Coldstream Canyon, in Truckee has similar geology and has had similar land use in the past, Wallace said. Her agency and the Forest Service are sharing information to help the council restore that watershed.

If you have information, comment or input regarding the Blackwood Creek Phase Three Restoration Project, respond during the 30-day comment period ending on February 24. Send comments in written or electronic form to the Lake Tahoe Basin Management Unit’s Craig Oehrli, interdisciplinary team leader, at coehrli@fs.fed.us, or in person at 35 College Drive, South Lake Tahoe, California, 96150. Or call 543-268.

Office hours for hand-delivered comments are 8:00 am to 4:30 p.m., Monday through Friday, excluding holidays.


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