Annual Lake Tahoe Summit Puts Spotlight On Water Quality

President Barack Obama will shine a national spotlight on environmental issues facing Lake Tahoe at the 20th Annual Lake Tahoe Summit. 

The 20th Annual Lake Tahoe Summit brings together federal, state and local officials to highlight work done to protect and preserve the lake.

Jesse Patterson with the League to Save Lake Tahoe is about to launch his boat at the Tahoe Keys Marina in South Lake Tahoe. We're going to get an in-depth look at some of the lake's biggest environmental problems.

Before we even step foot off the dock, Patterson looks down at the water and shakes his head.

“This is lake water," he says. "This should be clear. We should be able to see the bottom perfectly, but I don’t think you could see down six inches right now.”

The water is green and murky, choked with an invasive vine-like water weed called Eurasian milfoil. The plants can suck up all the oxygen in the water and kill native species.

Boating through them is difficult and helps spread plant fragments, which is how they grow.

"You can see over the corner, look at all the fragments from the plants, all day every day. Each one of those is a source of a new infestation," says Patterson.

This is the biggest infestation at 172 acres. There are about 20 areas around the lake where aquatic invasive weeds grow. We motor along the lake’s south shore to see another threat to water clarity. Patterson points to a pipe.

“It’s a corrugated pipe that’s draining the street and the parking lot and the Safeway and all that stuff, just straight out," he says. "It’s untreated, and it’s just another example of the nearly 500 pipes that are draining into lake Tahoe, with all varying forms of treatment. Some with none.”

Patterson says at the first summit in 1997, Lake Tahoe’s water clarity was at an all-time low. Since then, millions of dollars have been spent building infrastructure to prevent stormwater runoff. But Patterson says more needs to be done. The California Tahoe Conservancy is now in the process of restoring the Upper Truckee River Marsh, which Patterson says would naturally filter stormwater.

“Hopefully that will restore over the course of five to ten years that wetland Delta system we once had, which will filter out tons of clarity degrading fine sediment.”

Patterson says it has the potential to be the most beneficial project to date for Tahoe’s water clarity. He hopes money for such projects will come from the reauthorization of the Lake Tahoe Restoration Act. The legislation would provide more than $400 million in federal spending at Lake Tahoe over 10 years. Patterson says past investments have paid off.

“In '97 when the first presidential summit happened and Clinton and Gore were here, it was the worst clarity of Lake Tahoe in its recorded history. Twenty years later, we’ve arrested that decline. The trends are showing that we’ve stopped that decline.”

But Lake Tahoe still faces its biggest challenge - climate change.

“Longer growing seasons for aquatic invasives and algae, and more rain than snow, and that rain brings pollution and runoff from the land. Basically the same impacts we were dealing with in '97, just exacerbated.”

This year’s State of the Lake Report found the average surface temperature of the lake in 2015 was the warmest ever recorded