In 2017, heavy storms deposited large quantities of silt in Collier Canyon Creek culverts and a mitigation basin maintained by the City of Livermore, reducing capacity and damaging valuable habitats. The goal of this project is to reduce the threat of flooding along Collier Canyon Road and adjacent residential and commercial development as well as improve the downstream habitat by implementing culvert, drainage, and road improvements. These improvements will detain flow upstream of Collier Canyon Road, thereby minimizing the amount of sediment and debris entering the culverts and reducing capacity. This project will include:

• modifications to the existing culvert, 
• installation of weir structures and short floodwalls along the road shoulders, and
• an emergency overflow storm drain line and ancillary improvements.