Hawthorne Undergrounding Utility Project

The overhead utilities in the San Francisco Bay Area town of Tiburon, California needed improvements in safety and reliability. Because the utilities were exposed, they were subject to storms and adverse environmental changes that cause broken lines, falling poles, and degradation over time.

The Tiburon Public Works Department called on Harris to provide environmental planning and compliance documentation for undergrounding the Pacific Gas & Electric (PG&E) Power, AT&T Telephone, and Comcast Communications aerial facilities. Currently in progress, the undergrounding of these wires will minimize risk and improve views of Richardson Bay for local residences and the nearby Belvedere Tennis Club.

Core Elements

Harris’ environmental impact planning covered the installation of:

• Mainline underground power
• Telephone and cable conduits
• Appurtenant manholes and pullboxes
• Subsurface and surface-located transformers

Beyond the Blueprints

Harris prepared an Initial Study/Mitigated Negative Declaration for the project, which included extensive coordination with Caltrans and BCDC. Harris worked extensively with Caltrans and the Federated Indians of Graton to determine mitigation measures and monitoring requirements to protect sensitive cultural resources throughout project implementation.

Throughout the project area, a number of drainages occur that support water features and riparian vegetation. Harris biologists worked with the Town engineers, USACE, CDFW and Caltrans to ensure that the drainages and ditches were protected and avoided throughout the undergrounding of the utilities. Preconstruction surveys were also undertaken for sensitive species, including California red-legged frog and western pond turtle.