When I used to go to Lake Tahoe in the 1960s and early 1970s, the water was such a clear blue it seemed magical. If you took a boat out, you could look straight through to the bottom to incredible depths. The lake area also wasn’t very crowded. You could find beaches all around the lake where it was just you and a handful of other people, if that many. Hiking in the nearby Desolation Wilderness was the same. Sometimes our family group was the only one on the trail to the lovely Eagle Lake.
For complicated reasons, there was a long hiatus between my last childhood trip to Tahoe, probably in the mid to late 1970s and the resumption of those trips. In the last five or ten years, I’ve started going to Tahoe again, but I’m always a little depressed when I do. It’s still beautiful up there, with the Sierra mountains and the big blue lake. The whole area, however, is so crowded, more crowded even than the nice Bay Area suburb in which I live. Places that I remember as just trees and trails are now packed with condos and wall-to-wall houses. All of the condos and houses sport suburban style gardens, with big lawns and flower beds — all of which use tons of water and fertilizer, and non of which are indigenous to the Sierra area.
The trails, when you go on them, are packed. A journey to Eagle Lake, which used to be a cheerfully solitary activity can full like pushing your way through a busy downtown street. There are just hordes of people heading up and down at all times of the day.
The lake itself has changed too. I went with friends to a beach I used to frequent as a child. I remember wading out into the crystal clear water, or sitting on the shore sifting through the sand for agates. On the shore, one is now as likely to find litter as one is to find crystals and agates. As for the water, it’s filled with a slimy brown algae that coats you as you go in. Standing knee high in the water, you can’t see your feet.
The changes I see aren’t just the product of a golden glow of nostalgia. The whole Tahoe area really is changing, and changing rapidly at that:
Lake Tahoe, the jewel of the Sierra once so crystal-clear that Mark Twain likened boating on it to floating on air, is warmer and soupier than ever before as a result of climate change and human activities, UC Davis scientists reported Wednesday.
Their 45-page report, the most comprehensive ever done on the lake, outlines significant changes in weather patterns over the years, including less snowfall and more rain, deteriorating lake clarity and increasing water temperature in the Lake Tahoe Basin – all of which could increase invasions of exotic fish and plant species.
“Change is a difficult thing, and the lake is changing,” said Geoff Schladow, director of the UC Davis Tahoe Environmental Research Center and co-editor of the report. “But I think it is too early to say that our efforts are in vain. We can’t judge each year in isolation. It’s not all doom and gloom.”
But there is reason to be concerned about the second-deepest lake in the United States, researchers said. Conditions appear to be getting worse, even as environmental and planning agencies work to reduce runoff from residential and commercial development and improve water quality in the lake.
The most significant finding, according to Schladow, is how much the Tahoe climate is warming. Low temperatures at night have risen 4 degrees on average, and the number of days with temperatures that averaged below freezing dropped from 79 days to 52 days since 1910.
The percentage of precipitation that falls as snow has also decreased, from 52 percent to 34 percent in the 96 years studied.
All of this is apparently having a major effect on the lake. The average temperature of the surface water in July has increased almost 5 degrees, from 62.9 degrees to 67.8 degrees since 1999, according to the report. The water temperature was 78 degrees on July 26, 2006, the warmest in Lake Tahoe’s recorded history.
Clarity also has suffered. In 2006, Lake Tahoe was clear to an average depth of 67.7 feet, based on how far from the surface researchers could see a white dinner-plate-size measuring tool known as a Secchi disk.
That’s 4.6 feet less than 2005. When measurements began in 1968, the lake was clear to an average depth of 102.4 feet. That’s how clear the country’s deepest lake, Oregon’s Crater Lake, is today, Schladow said.
It is impossible to say what the Secchi disk measurement would have been when Mark Twain visited Lake Tahoe in the 1860s, but it was nothing short of astonishing to him.
“So singularly clear was the water, that where it was only twenty or thirty feet deep the bottom was so perfectly distinct that the boat seemed floating in the air!” Twain wrote in “Roughing It.” He said even below 80 feet the water was as clear as glass.
“Every little pebble was distinct, every speckled trout, every hand’s-breadth of sand,” he wrote. “Down through the transparency of these great depths, the water was not merely transparent, but dazzlingly, brilliantly so.”
UC Davis experts say the clarity has deteriorated because fine particles from erosion, urban runoff and pollution have entered the lake. The particles fuel the growth of algae, which absorb light and increase temperature.
Certainly, bathed as I am in the glow of my halcyon memories of a childhood in a beautiful wilderness surrounding a crystaline lake, I find this news really sad. However, as I’ve noted before in my blog, things change and people need places to go. I was the last of the privileged generation who could afford (Thank you, Grandmother!) to spend time at what was once a pricey resort. Once it became more democratized and less privileged, it was inevitable that all the downsides of crowds would appear too. And as for climate change, well, whatever the cause, it’s happening and it’s going to affect the lake.
As it is, if I were master of the lake, the only change I would make would be to insist that people give up their lawns and flowerbeds (with their heavy fertilizer and water use, and damaging run off) and surround their homes with drought resistant indigenous plants.
At least I’ve got my memories….
Lake Tahoe in 1908
Filed under: Climate change