Why not tap Lake Tahoe?

Q: Is it feasible (politically and technologically) to pipe water from Lake Tahoe to the American River? – James Reagan, Rocklin

A: Let’s take the feasibility part first. Yes, it’s feasible, but it would be an expensive engineering feat.

If the choice is to pump the water, consider that the Interstate 80 and Highway 50 highway passes over the Sierra are about 1,000 feet higher than Lake Tahoe’s water elevation. These would be the lowest choices for a pipeline. That is shorter than the California Aqueduct’s climb over the Tehachapi Mountains (about 2,000 feet) but still would require massive pumps and pipelines and access to a large electricity supply.

A gravity-fed tunnel could work instead. Let’s keep it simple: Tunnel due west from Homewood to Hell Hole Reservoir. The reservoir is operated by the Placer County Water Agency, sits about 1,300 feet lower than Lake Tahoe, and drains into the American River. Such a tunnel would run about 10 miles. It’s difficult to estimate tunneling costs, but we can safely guess it would cost hundreds of million of dollars. This could be financed by water bonds if the state and water users were willing to pay.

The real obstacles are not engineering. First of all, Lake Tahoe’s only natural outlet, the Truckee River, carries water into Nevada, not California, where it terminates at Pyramid Lake. This means there are no legal water rights to use Tahoe water in California, aside from a few local uses along the river’s path to Nevada.

The other factor is that Lake Tahoe is a world-renowned ecological treasure, which brings both legal protections and strong public sentiment. The lake is known as an Outstanding Natural Resource Water, a category under the federal Clean Water Act. It is also protected by a kind of treaty, called a “compact,” between California and Nevada. This is managed by the Tahoe Regional Planning Agency to regulate development and protect water quality. It’s safe to say that diverting Tahoe water to California would alter the lake’s sensitive ecology and would not be permissible under the compact.

“To do anything of that nature would be met with great resistance from all the people who care about the lake,” said TRPA spokeswoman Julie Regan. “Which really is the icing on the cake.”

– Matt Weiser

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