Sen. Dianne Feinstein, D-Calif.

It was 142 years ago that John Muir, the famous naturalist and conservationist, first laid eyes on Lake Tahoe.

Muir wrote in a letter to a friend that he “sauntered through the piney woods, pausing countless times to absorb the blue glimpses of the lake, all so heavenly clean, so terrestrial yet so openly spiritual.”

He continued: “Tahoe is surely not one but many. As I curve around its heads and bays and look far out on its level sky fairly tinted and fading in pensive air, I am reminded of all the mountain lakes I ever knew, as if this were a kind of water heaven to which they all had come.”

Each of us who has fallen in love with Lake Tahoe has a similar story, that jaw-dropping first encounter.

Mark Twain wrote, “As it lay there with the shadows of the mountains brilliantly photographed upon its still surface I thought it must surely be the fairest picture the whole earth affords.”

There’s a reason that Lake Tahoe attracts such notables and such fawning reviews. It’s a world treasure with an unmistakable spirit.

That’s why John Muir pushed for it to be a National Park. It’s why California and Nevada leaders came together in the 1960s to establish formal means to protect it. It’s why the federal government for nearly 20 years has devoted funds to Keep Tahoe Blue. And it’s why last month we introduced legislation to continue that fight.

There are many threats facing Lake Tahoe, and unless we take action, the pristine beauty Muir described will soon be only a memory.

We joined our colleagues, Senators Harry Reid and Barbara Boxer, to introduce the bipartisan Lake Tahoe Restoration Act of 2015, a bill to protect Lake Tahoe and the Tahoe Basin for generations to come.

The push started in earnest in 1997 when President Bill Clinton and Vice President Al Gore hosted a Presidential Forum on Lake Tahoe. In 2000, we were able to pass legislation to begin a 10-year, $900-million restoration and conservation effort.

It’s been hugely successful. We’ve been able to restore more than 16,000 acres of wildlife habitat, implement innovative transportation solutions, significantly reduce erosion that clouds the lake, improve water clarity and mitigate the risk of wildfires.

Since 1997, the federal government, California, Nevada, local municipalities and the private sector have provided a combined total of $1.8 billion.

Unfortunately, the resources that Washington chipped in have largely dried up. Our bill recommits the federal government to continue the vital projects that are saving Tahoe every day.

The bill includes fuel reduction projects to protect against the threat of wildfires. It prioritizes environmental restoration projects. And in order to strengthen the ecosystem, we allocate funds for an extensive invasive species control program.

These resources really can have an impact. We’ve seen progress from decades ago usher in a new era, and we need to maintain that drumbeat.

Without additional support for Tahoe, we fear the beauty that Muir, Twain and countless others have enjoyed may be short-lived.

The vistas and natural wonders deserve to be timeless.

Let us all recommit ourselves to protecting Lake Tahoe’s special qualities. As we preserve the water and the land, we’ll also be preserving the lake’s singular spirit.

Sens. Dean Heller, R-Nev., and Dianne Feinstein, D-Calif., will join other key stakeholders at the 19th annual Lake Tahoe Summit at Round Hill Pines in Zephyr Cove at 10 a.m. on Monday, Aug. 24. The event is open to the public. This year’s theme is Connecting Lake Tahoe’s Environment and Economy through Innovation and Transportation. This commentary originally appeared in the Sierra Sun.