A petition for such a bridge, sponsored by Bike Walk Alameda, now has almost 800 signatures, up from just over 450 when Action Alameda News wrote about it late last month.
Walking or cycling on the narrow passageway through the Posey Tube between Alameda and downtown Oakland is a loud, noisy and dirty affair; emissions soot on the walls is thick enough to serve as a medium for graffiti.
But United States Coast Guard review and approval is critical to any such span being built.
Dan Dewell, a public affairs officer for the 11th Coast Guard District, which operates out of Coast Guard Island, east of the current proposed location for a bridge, told Action Alameda News, “the Coast Guard’s review and approval of plans for any span across a navigable waterway are required to ensure safe vessel operations.
“The waterway involved is used by a variety of military, government, and commercial vessels in addition to recreational craft. Should the city, state, or other entity reach the point of formally proposing the construction of a bridge or other structure over a navigable waterway, a formal review of plans and construction by the Coast Guard would be required.”
Dewell referred to a 2008 letter sent to the City of Alameda by the Coast Guard, in response then to a request to review a proposed estuary crossing.
The letter notes that the General Bridge Act of 1946, as amended, governs the placements of bridges across navigable waters, and that “the estuary is considered navigable in its entirety, for bridge permitting purposes.”
It goes on to say that any new bridge west of the Park Street bridge would have to have a vertical clearance of 175 feet above mean high water and span horizontally 600 feet, pier face to pier face.
For comparison, the Duluth Aerial Bridge, in Minnesota, spans 390 feet with a vertical clearance of 135 feet. The Duluth bridge was one referenced in a 2009 Estuary Crossing Feasibility study.
The study references three other bridges, including the Interstate Bridge between Washington and Oregon (275 ft lifting span), the Delaware River Burlington-Bristol Bridge (540 ft lifting span) and the Multnomah County, Oregon, Hawthorne Bridge across the Willamette River (477 ft lifting span).
A new bridge on the estuary that meets the Coast Guard’s requirements would seem to need a lifting span longer than any of the four reference bridges.
To minimize rush-hour automobile congestion, the existing estuary bridges are not required to open during commute hours, except for emergencies or public safety reasons.
But those bridges are all east of Coast Guard Island and maritime commerce activities in the estuary from there west to the Port of Oakland.
The desired new bridge could be required to remain primarily in the open, navigable, position, and close on demand to cyclists and pedestrians.
It would also need to remain in the open, navigable, position, during any periods that the bridge tender stations are not staffed, reducing availability to pedestrians and cyclists.
So far, Dewell said, the Coast Guard hasn’t received any proposed plans to review and comment on since the 2008 letter.