In addition to required environmental work, the California Department of Transportation (Caltrans) will fund the Mariposa Supplemental Environmental Project. The project will provide real-time monitoring along a wild and scenic stretch of the Merced River to detect excess turbidity and pH levels during Caltrans’ Ferguson landslide rehabilitation project. Data will be collected both before and during removal of the rock debris at the base of the slide. When completed, Caltrans will have extensively monitored the river upstream and downstream of the rock slide and provided a way to mitigate discharges through a remote and early detection system designed to improve response time on problems near sensitive water bodies or watersheds.

This project is part of a $2.7 million dollar settlement between the Central Valley Regional Water Quality Control Board and Caltrans regarding alleged violations of two stormwater permits governing the State Route 108 East Sonora Bypass Project in Tuolumne County.

The settlement resolves the allegations that work on a Caltrans project resulted in the discharge of approximately 3,000 m3 (800,000 gal) of sediment-laden stormwater to waters of the United States during a series of storms in late 2012. Caltrans has informed the Central Valley Water Board it has filed a dispute with its contractor and intends to seek appropriate reimbursement from the contractor for the penalties. Read more.