The Marin Municipal Water District is spending $50,000 to get rid of rogue pathways on sensitive areas of Mount Tamalpais. Some of them were created by people going off the beaten path, while others were purposely carved by renegade hikers.
Environmentalists say the illegal trails damage native plants and even hurt local salmon.
"When the hillside erodes and the sediment is delivered downstream, it can actually clog the habitat that is used for the coho salmon," said Carl Sanders with the Marin Municipal Water District. "The coho likes a certain kind type gravel to lay their eggs in."
The Conservation Corps North Bay will put in bushes, signs and even fences to block off undesired paths.