Miami-Dade hasn’t changed the most basic form of flood protection – the minimum height for building things like roads and new homes – in 40 years.
Now a new proposal on the table could nearly double that standard, a dramatic change that reflects two inevitable realities: sea rise poses an increasingly imminent threat and adapting to it will raise construction costs.
A new minimum height of 6 feet for things like roads, sea walls, canal banks and lots sounds high, but the visual impact will likely be minor for everywhere except the most low-lying pockets of the county. The costs of such a change, if the county commission agrees to pass it, are unclear. It could add up in a community squeezed by an affordable housing crisis and also facing a future of more frequent flooding.
“It’s a resilience measure,” said Marina Blanco-Pape, director of Miami-Dade Division of Environmental Resources Management’s (DERM) water management division. “The idea is you’d build to a high enough elevation that with a 10-year storm event in 2060 you’re free of flooding.”
Technically, the proposal from DERM would bump the minimum elevation from 3.45 feet to 6 feet NAVD88. That stands for North American Vertical Datum, a national fixed measure used by surveyors, engineers and others to determine elevation used instead of “sea level,” which is shifting due to climate change.
But like most other measures to build a safe building, like stronger roofs or windows, the expense can add up.