ALDOT offers theory of climate change as justification for $900 million Bayway portion of I-10 Mobile Bay Bridge project
Despite being a topic of mockery for President Donald Trump, the federal government’s view of climate change weighed mightily on the cost of the Alabama Department of Transportation’s (ALDOT) proposal for the $2.1 billion Mobile Bay Bridge project.
According to ALDOT documents, at least $900 million of the $2.1 billion costs is for commitments to replacing the existing I-10 Bayway. The need for replacing the existing Bayway, which was laid out by ALDOT in a document responding to questions from Tyler Fingert and Brendan Kirby of Mobile’s FOX 10 WALA and Andrea Ramey of Mobile’s NBC15 WPMI is attributed in part to “federal regulations,” and among those is a Federal Highway Administration (FHWA) directive to “integrate consideration of climate change and extreme weather event impacts.”
The existing Bayway that was built in 1977 has already survived a Category 4 hurricane, Hurricane Frederic in 1979.
ALDOT’s response to the question from Ramey as to why the Bayway was required to be raised and widened named “storm surge analysis, federal regulations, ALDOT design standards, and cost” in its response:
The Alabama Department of Transportation is committed to providing safe and efficient transportation facilities to the driving public. To that end, we are working to develop the Mobile River Bridge and Bayway Project which features three key elements: the Mobile River Bridge, a new eight-lane Bayway above the 100-year storm surge level, and modifications to seven interchanges. Many factors went into the decision to replace the Bayway with a higher structure as opposed to widening it. Those factors include storm surge analysis, federal regulations, ALDOT design standards, and cost.
Later in the document, ALDOT named the FHWA’s directive on “climate change” as part of the federal regulations:
In December 2014, the FHWA issued Order 5520 Transportation System Preparedness and Resilience to Climate Change and Extreme Weather Events. This directive requires FHWA “to ensure that their programs, policies, and activities for which they are responsible integrate consideration of climate change and extreme weather event impacts and adaptation into its planning, operations, policies, and programs, in order to promote climate change and extreme weather event preparedness and resilience. Proactive management involves developing engineering solutions, operations and maintenance strategies, asset management plans, and transportation programs that address risk and promote resilience at both the project and systems levels.”
In the summary of the written response to Fingert, Kirby and Ramey, ALDOT cites an FHWA requirement the new construction “must be resilient to climate change”:
In summary, bridges must be designed to avoid significant encroachments on the 100-year floodplain and to provide clearance above the 100-year floodplain unless it can be proven that it is not practicable. They must also be designed to withstand storm surge and wave action impacts, and they must be resilient to climate change and extreme weather events. Engineers meet these requirements by following the methodologies set forth in the U.S. Department Transportation’s Hydraulic Engineering Circulars, Executive Orders, and Orders, as well as the 2008 AASHTO Guide Specifications.