Unchecked development paved over much of Tahoe’s natural pollution filtration system – its marshes and wetlands. Now, rain falling on our roads, buildings and parking lots releases fine sediment pollution, the number one threat to Lake clarity. Rain and melting snow also flushes trash and nutrients downhill to the Lake’s shoreline, polluting beaches and encouraging algae to grow. Climate change makes matters worse, as warmer temperatures prompt more rain than snow, intensifying erosion and harmful runoff. The League to Save Lake Tahoe combats pollution through the programs below.