Bottom of Lake Tahoe to be mapped

"It is very important and is a long time overdue," says Susan Lindstrom, a local consulting archaeologist. "We will finally see what the exact topography looks like. Our perception of the area may not change dramatically, but it will provide more fine-grained results."

"We are bringing a boat to Lake Tahoe to get a three-dimensional photographic view of objects as small as a Volkswagen (Beetle)," said Dale Cox of the U.S. Geological Survey, the federal organization behind the study.

"The last one was done in the 1920s," Cox added. "This one will give us a 3-dimensional picture that will tell us the exact area of Lake Tahoe."

The project will take about two weeks. A 27-foot boat is due to arrive from Louisiana by Aug. 2, loaded with sensitive sonar equipment that will bounce signals from the vessel to the lake floor and back to an on-board computer.

"It is almost like a mowing a lawn. You go back and forth, back and forth," Cox said in describing the process.

The technology, known as multi-beam bathymetry, has been used extensively to map the ocean floor off the coast of California and other areas.

"There are a bunch of questions surrounding the depths of Lake Tahoe. I have heard about stage coaches that contain gold, locomotives and B-52s that are on the bottom of the lake," Cox said. "Those could be answered. We have found previously undiscovered ships off the coast of California."

The biggest known vessel at the bottom of Tahoe is the 169-foot S.S. Tahoe, a mail and passenger steamer scuttled in 1940 in about 400 feet of water.

Lindstrom added there are Washoe tribal stories of islands and other land forms on the lake, and the mapping will prove or disprove those accounts.

Less colorful but still important is the mapping of old, submerged tree trunks, and use of the data to help understand sediment patterns.

Lindstrom said she already has found 22 stumps, which proved to be about 6,000 years old.

"That means that back then, the water level of the lake was at least 20 feet lower than it is today," she said.

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