Tahoe Transportation District Blog: What TMDL means for the lake

A Total Maximum Daily Load is a regulatory term in the U.S. Clean Water Act describing a value of the maximum amount of a pollutant that a body of water can receive while still meeting water quality standards.
While Lake Tahoe is known for its famed water clarity, TMDL is what is causing the decline. A 2007 report by the California Regional Water Quality Control Board Lahontan Region and the Nevada Division of Environmental Protection indicates that fine sediment particles are the primary pollutant. The November 2010 Lake Tahoe Total Maximum Daily Load (TMDL) Report attributes 72% of these fine sediments to urban upland run-off. Disturbances due to the transportation system — cars, mass transit, parking lots, bus stops, etc. — are, directly and indirectly the primary source. Atmospheric deposition contributes 15 percent, non-urban runoff 9 percent, stream channel erosion 4 percent and shoreline erosion 1 percent.
Go here to read the entire Tahoe Transportation District blog.