Visual report: How sea level rise threatens the Bay Area’s roads

By John King, San Francisco Chronicle, July 16, 2021

“ ‘This is a much bigger thing than most people realize,’ said Randy Rentschler, director of legislation for the Metropolitan Transportation Commission. ‘The whole area is a transportation network at risk.’

“That risk is the result of generations viewing the shoreline’s shallow tidelands and mudflats as easy places to build the infrastructure required by a growing region, including highways and railroad tracks lines …

“While many [potential roadway floods] involve relatively short sections of roadways, where major arteries cross mud flats and marshes only a few feet above sea level, nearly all nine miles of Highway 37 in Sonoma County are vulnerable.

“By replacing the current road with an elevated causeway, advocates suggest, existing marshes could be enlarged to serve as giant, green sponges to protect the southern portions of Napa and Sonoma counties while also reducing the risk that the rupture of a single levee could submerge Highway 37 and adjacent land.

“ ‘Everyone sees there’s a huge opportunity — we can improve the marshes and improve the road,’ said Jeremy Lowe, a senior scientist with the San Francisco Estuary Institute …

“For now, Caltrans is working with federal officials to combine planning with environmental studies to speed up a makeover. The Metropolitan Transportation Commission is exploring how to loosen the commute gridlock in the short term. But those initiatives would cost money, too.

“This is the real challenge facing Highway 37 in coming decades: It is only one of many weak links in the intricate transportation chain that loops around the bay.”

Read the full special report here, including interactive maps of projected sea level impacts on the Bay Area’s highwaysand illustrated diagrams of sea level rise impacts on Highway 37. (~7 min.)

Related articles: Stanford researchers show sea level rise may worsen existing Bay Area inequities. Read Stanford News Service’s coverage of the research here (July 12, ~3 min.).

A San Francisco Bay Area case study analysis suggests using sea walls to defend coastal land could worsen flooding events elsewhere. Read Ars Technica’s coverage of the study here (July 15, ~5 min).

Many of Silicon Valley’s tech companies built their campuses on waterfront property at risk to sea level rise. Read a visual report by NPR here investigating how cities and corporations will share the responsibility of flood protection (July 27, ~7 min.).

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