Ground transportation assets in the project area include the San Francisco-Oakland Bay Bridge; the Hayward-San Mateo Bridge; Bay Area Rapid Transit (BART); Interstates 80, 580, 880 and 980; State Routes 92, 61, 185 and 238; passenger and freight rail; the Oakland, Alameda, and Harbor Bay Island Ferry Terminals; AC Transit local and transbay bus routes; arterials, collectors, and local streets; the Webster and Posey Tubes; local bridges to the City of Alameda; the San Francisco Bay Trail; and maintenance yards. All of these assets could be affected by: changes in daily tide levels; storm events that cause larger, longer, and more damaging floods; and elevated groundwater levels. Damage or disruption of transportation systems in the project area could have serious and significant consequences on commuter and goods movement, public health and safety, and quality of life in the region.
Many of the ground transportation assets in the project area are vulnerable to sea level rise, storm events, and elevated groundwater levels. Understanding the underlying causes and components of these vulnerabilities is challenging because most planning data (e.g., storm drain and bridge crossing locations) are not readily available to the public, and design and survey data (e.g., structure elevation information) are not easily accessible to asset managers, for example through searchable, system-wide, centralized databases.
Tubes, tunnels, and roads with below-grade sections are particularly vulnerable because these are largely below current sea level and their openings are generally unprotected and at grade. This includes the roadways that serve the Oakland International Airport (Airport Drive and Hegenberger Road), the BART Oakland Airport Connector (OAC), the Port of Oakland’s seaport and the Webster and Posey Tubes that connect the Cities of Oakland and Alameda. Elevated and at grade roadways are vulnerable to flooding, higher groundwater and exposure to salt water that can corrode the reinforcing materials in concrete structures, damage pavement, structural sections and landscaping, and cause major dewatering problems during future construction. Although much of the BART system in the project area is elevated, assets critical to operations are located at grade or underground, and have mechanical or electrical components that are highly sensitive to even small amounts of water. The disruption or damage of these assets could shut down the entire BART system or a large portion of it. This would have significant consequences, including more roadway congestion, emissions and associated air and water quality issues caused by more people driving, and an increased number of riders on other modes of transportation where capacity may already be strained.
Temporary flooding of vulnerable sections of interstate and state highways may not cause permanent asset damage but will have potentially significant consequences on both goods or commuter movement and access for emergency responders as there is a lack of alternate routes with adequate capacity to serve all of the traffic needs. There are very few options for rerouting goods movement to/from the Port of Oakland seaport and Oakland International Airport if I-880 was disrupted, in particular because this segment provides the main point of access for truck traffic. Rerouting truck traffic can be challenging due to road use restrictions on alternate routes such as I-580, I-980 and local streets and roads.
Goods also move to and from the Port of Oakland seaport on heavy rail. Rail lines within and beyond the project area are vulnerable to sea level rise and storm events. In general, rail is highly sensitive to even small amounts of water on the tracks, and if a portion of track is damaged it often results in the closure of many miles of connected track. The region’s capacity to withstand impacts to rail infrastructure is further hampered by the lack of redundant or alternative rail lines in the region. Relocating or adding new rail infrastructure, is costly and significant time and money are needed for planning, financing and implementing changes to the region’s rail network. Disruption of the rail system would lead to an increase in the number of trucks needed to transport cargo, having negative and widespread effects on road congestion, air quality, and community noise and quality of life.
The Bay Trail is highly vulnerable to sea level rise and storm event flooding due to its construction and location along the shoreline. Erosion, poor drainage, and surface damage can all result in lengthy closures. Consequences of temporary or permanent closures along portions of the trail can be significant because it functions as a system of interlinked pathways. Adaptive measures can be taken, such as building with different types of materials, improving drainage, and using boardwalks and bridges, but at some point these will become ineffective. Loss of connected Bay Trail segments could result in more people driving rather than walking or bicycling to their destinations and reduced shoreline access opportunities in general and, in particular, for people with disabilities or reduced mobility.
For more information:
- Lindy Lowe