Pipe Keepers is the League’s citizen science program to address the leading threat to Lake Tahoe’s clarity: pollution in stormwater runoff from the Tahoe Basin’s urbanized areas. Tahoe’s marshes and wetlands, which had acted as natural pollution filters, are diminished or gone so when rain hits our roads and parking lots, it washes off fine sediment pollution into stormwater pipes to the Lake, clouding its water. League experts train community members to collect stormwater samples from pipes throughout the Tahoe Basin, which we analyze for turbidity, an indicator of fine sediment.