Unsafe levels of livestock associated pathogens infest alpine waters
Alpine lakes and streams of the Sierra Mountains are fouled with Giardia, E. coli, and other pathogens from livestock grazing on Forest Service Lands. Dr. Michael J. Connor, the California Director of Western Watersheds Project is one of the authors of the paper.
You can read the paper here:
Derlet, R. W., Goldman, C. and Connor, M. J.: Reducing the Impact of Summer Cattle Grazing on Water Quality in the Sierra Nevada Mountains of California: A Proposal. Journal of Water and Health. 8(2): 326-333. 2010.
Livestock waste found to foul Sierra waters.