Mr. Clarity’s job is clear
Call him Mr. Clarity. Or you could call him what he’s been for 34 years: a data collection machine.
Bob Richards came to Tahoe in 1969 to fill a temporary position for the UC Davis Tahoe Research Group and never left. His job is to measure the clarity of Lake Tahoe.
“It’s a responsibility I don’t take lightly and my goal is to do it right,” Richards, 64, said. “It’s a bit unsettling, intimidating and humbling to realize so much effort, money, time is going into the restoration of Tahoe that’s based on a very simple exercise I personally do out on the lake every 10 days or so.”
It’s because of his diligence that people know the lake has lost about a foot of clarity a year in the last 30 years. Measurements in the last five years, however, indicate the lake’s clarity has stabilized, even improved. Richards said he’s hopeful environmental restoration work is responsible for the improvement in clarity readings but it’s too early to say.
“Part of the significant change in clarity is due to meteorological conditions,” Richards said. “But we can remain hopeful the projects are having some effect.”
Richards said until 10 years of data show that the clouding of the lake water has stabilized or improved, people should hold off in thinking the lake water is healing.
When he first started collecting information on Tahoe — which contains enough water to flood California 14 inches deep — its water was so clear it had a purplish hue. Today when he looks off the side of his vessel, Richards often what he calls the halo effect.
“It used to be a cobalt-blue, almost a purple-blue, in the early years,” Richards said. “Now … the water is sort of cloudy, not that crisp color it used to be.”
Every 10 days Richards uses a white disc to measure lake clarity. Relying on 20-20 vision, he marks down the depth the disc disappears from view at a spot on the West Shore. It was chosen because earlier data collections indicated it best represents average conditions on the lake.
“I joke with people out on the boat (about the clarity),” Richards said. “It’s not because the lake is changing, it’s because my eyesight is getting bad.”
Over the years, Richards has documented a decrease in lake clarity from about 100 feet to about 70. His measurements vary with the weather and time of year.
Mid-winter produces the deepest clarity readings. By then, nutrients and sediments that flow into the lake from the snowmelt have settled and stormy weather can bring upswells of clear water from deep in the lake. Richards recorded the deepest reading in the history of the lake in March 2002 — 135 feet.
East Shore waters are clearer than the West Shore’s because less snow falls on the East Shore. Consequently there are fewer creeks and streams that empty into that side of the lake. Less runoff translates to water that’s about 3 feet clearer on the East Shore, Richards said.
Richards’ work is done off the side of the John Le Conte. The vessel was named in honor of the man who in 1873 first measured lake clarity. A monthly publication called the Overland Monthly documented Le Conte’s trip, which took place in September.
Le Conte, who attended UC Berkeley, recorded clear water down about 33 meters, or 107 feet. That’s similar to measurements Charles Goldman, director of the UC Davis Tahoe Research Group, took when he started work at the lake in 1958.
In the thousands of hours Richards has spent on the lake, he says he holds no spot as a favorite. Sunrises and sunsets are great. So is being out on the Le Conte at 2 a.m. under a full moon just after a snowfall.
“I think it has so many different moods,” Richards said. “I haven’t lost my appreciation of the environment at all. If anything it more dear to me than it was. I’m not tired of the lake at all.”
Richards plans to retire next year. Goldman says he doesn’t want to contemplate losing such a resource.
“He’s a one-man army out there collecting data,” said Goldman, who taught Richards liminology, the study of lakes, as an undergraduate at Davis.
“He’s been the backbone of our field operations for over 30 years,” Goldman said. “His experience is just truly exceptional. Everyone who sees him work wants to hire him away from us.”
— Gregory Crofton can be reached at (530) 542-8045 or by e-mail at email@example.com