Bacteria Bug Sierra Water Researcher

by Mark Grossi
Fresno Bee - September 13, 2005

His findings for the past five years, published in a journal called Wilderness and Environmental Medicine, show a definite trend. Trouble spots cluster around places used by people and large animals, such as horses or cattle.

Authorities advise people to filter water before drinking out of any lakes and streams.

Says Harold Werner, wildlife ecologist with Sequoia-Kings Canyon National Parks: "This is exactly where California's water begins. Water up here probably ranks as exceptional around the country. I gulp it down without filtering it. But you need to be careful when you get around concentrated camping areas."

No ordinary working day

Dr. Robert Derlet of the University of California at Davis walks along the north shore of Middle Gaylor Lake as he samples water in Yosemite National Park. Derlet has confirmed there are bacteria linked to human feces in lakes and streams in the Sierra Nevada. Eric Paul Zamora / The Fresno Bee

Derlet is figuring out where the bad spots are, and Middle Gaylor apparently is not one of them. He takes samples, looking as though this is just another day at the office. But what an office.

"You can see Cathedral Peak that way," he says, scarcely winded as he walks at 10,500 feet. "Mount Dana is behind us. Kuna Crest is over there. Look at this meadow. The National Park Service should be commended. This area is just for day use, no camping. It is beautiful."

It would seem a bit of a stretch for a medical school professor and emergency room doctor to do such field work. But the Sierra is Derlet's passion.

Wearing sterile, blue rubber gloves, he carefully scoops water out of Middle Gaylor Lake for testing. At this lake, he has sampled the same three places for years.

Derlet, 56, would love to return here and to dozens of other sampling locations for the next 15 years so he could document changes. He would quit his day job if he could make a living hiking and checking water in the Sierra.

He gets various grants to do his water work, but money is not easy to find. The laboratory tests on his water samples are not cheap.

"People tend to take clean water for granted," he says, "until there's some kind of problem. We need to support this kind of research better."

On this morning, Derlet rises before the sun. His first stop takes him to a gurgling creek beneath the azure sky at the Sierra crest. The 44-degree water is like nothing that comes from a tap.

"I do enjoy coming here," he says.

"Dr. Bob," as his medical students call him, was a hiker long before he took up the stethoscope. His father started taking him on Yosemite backpacks when he was 5 years old. He has been an outdoor junkie for the last half century.

"One way or another, I've hiked every trail from Mount Lassen in the north to the Golden Trout Wilderness to the south," Derlet says.

Friends sometimes hike with him, but he's often a solo act. His time away from home takes him to such places as the riveting volcanic formations of the Carson-Iceberg Wilderness in the Stanislaus National Forest.

Later this month, he will backpack 20 miles in Kings Canyon National Park, visiting streams and lakes in the rugged southern Sierra.

"You get to know the rangers in the areas where you camp," he says. "I'm never very far from a ranger, and you make sure they know where you are."

He drinks the water

Backpacking solo generally is considered a no-no for all but the most experienced outdoors enthusiasts. With no partner to go for help, a backpacker with a broken ankle could be stranded.

Even a bout of severe diarrhea would seem risky for someone alone in the wild.

Strangely, Derlet generally doesn't use a filter at all — he drinks right out of lakes and streams.

That's because he avoids tainted water, which is often found where people camp or animals have grazed.

On his hike to Middle Gaylor Lake, he works up a thirst, walking up a 500-foot ridge not far from Tioga Pass.

He dumps his city water, fills up on Yosemite snowmelt from Middle Gaylor Lake and drinks deeply.

He says even healthy mountain lakes contain 10,000 to 20,000 bacteria in every quart of water.

"There are many kinds of good bacteria that are not harmful to you," he says. "I'm worried about what's going on if I find no bacteria at all in the water."

Lower elevations seem more susceptible to contamination because of contact with people.

But problems can be found even in higher elevations.

Derlet's study in national forests detected coliform bacteria — a pathogen found in the colon — from 7,000 to 9,000 feet in the Hoover Wilderness.

At 9,900 feet in the Golden Trout Wilderness in a well-traveled place, he found coliform counts twice as high as the standard for treated sewage.

Coliform is an indicator that sewage is present in the water, and intestinal disorders can result.

But, up in the mountains, the scourge is considered to be giardia, a protozoan that causes diarrhea.

In one of Derlet's studies, he says the giardia danger appears overstated in the Sierra.

He says some backpackers' water filters might work well to exclude giardia but won't filter out bacteria.

Government agencies urge the use of a quality filter just to be safe.

"Have you ever talked with someone who has gotten sick from drinking water up here?" asks Yosemite spokeswoman Adrienne Freeman. "It is something you will never forget."

Derlet adds: "I figured you would have to drink 250 gallons in one day from Sierra water sources to find a problem. I've never had a problem.

"That said, there's always the chance that if you take a drink from a stream where an animal just pooped a half-mile upstream, it might be full of giardia."