Sierra Summit

Conversations and observations about California's mountains

April 26, 2010
Cattle contaminate high Sierra lakes and streams
cows from buckley.jpgIn case you missed it, my story about livestock grazing and water pollution in the high Sierra is well worth a look. 
The story examines the efforts of Robert Derlet, former director of the emergency room at the UC Davis Medical Center in Sacramento, to collect and analyze water samples from high Sierra lakes and streams over the past 10 years. In short, Derlet found U.S. Forest Service lands where cattle graze, including wilderness areas, were the most widely contaminated. He is using his findings - which have been published in peer-reviewed scientific journals - to call for the creation of up to five new national parks across the high Sierra. "This is where the water is the purest," he said. "This is what needs to be protected."
Anne Yost, regional rangeland program manager for the Forest Service, is skeptical. "You can prove a lot of different points with research," she said. Other scientific studies, she said, show the agency can successfully manage cattle in the high Sierra and protect water quality. 

 You can find the story at:

(Photo of cattle in the Stanislaus National Forest, north of Yosemite National Park, courtesy of John Buckley, Central Sierra Environmental Resource Center.)


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About Sierra Summit

The Author
Tom Knudson lives in the Sierra Nevada and travels widely throughout the range. His hobbies include fly-fishing, backpacking and cross-country skiing. He is the recipient of numerous journalistic awards, including two Pulitzer Prizes, one for a 1992 Sacramento Bee series "Sierra in Peril," a watershed work about environmental threats to the mountain range. E-mail Tom at

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