Lake Tahoe is California's most highly curated and micromanaged natural asset.

State and federal agencies, non-profits, and other groups have spent more than $3 billion over the past quarter century for some 800 projects aimed to protect and improve Lake Tahoe, but despite all of the billions lavished on the lake, questions remain about whether all of the funding has actually improved the quality of the lake and its surrounding environment.

The clarity of Lake Tahoe itself, an indicator of its overall health that measures how deep the naked eye can see, has declined by more than a third since 1968.

This whole time, I'm kicking this to keep myself flush against the rock, and then I'm going to sneak that cork in, and that's how we get our algae sample.

Important to monitor it year-round, all the time, so we can really see that change.

In 2023, the lake suffered one of its murkiest summers, with that year's average worsening by a whopping 34 feet compared to about half a century earlier.

Pollutants, largely from cars and roads, increasingly pour into the basin, including particles that muddy its waters and chemicals that feed algae blooms, along with the increasing volumes of plastic and other debris.

In some cases, the lake's algae could be toxic to people and their pets.

About $581 million, slightly more than a third of the government and private money spent in the Tahoe region since 2010, has funded recreation, transit, paved paths, and trail projects.

That includes $40 million for a new sports and aquatic center.

Those types of expenses are growing.

Since 2015, the projects now amount to 43% of the funding, twice the share of the previous five years, according to a CalMatters analysis.

For CalMatters, I'm Julie Cart.