Parts of California face repeated ocean flooding
July 12, 2017
• But if levees hold, Central Valley may be spared
• Worst will be in Alameda, San Mateo areas
The island community of Alameda, along with San Mateo, are expected to be among the worst-hit areas of California from rising oceans, according to a new report Wednesday from the Union of Concerned Scientists.
It says these areas as well as the Huntington Beach coastline in Southern California will experience high-tide flooding within the next few decades that will be chronic and extensive enough “to render neighborhoods, commercial districts, industrial zones, and recreational and other areas unusable.”
The report says communities will face either major coastal defense investments or the prospect of retreat from affected places.
The report indicates that as long as California Delta levees hold, the northern Central Valley ought to be protected from the rising oceans.
“Seas are rising more slowly on the West Coast than on much of the East and Gulf Coasts, which means that most California communities will have more time to plan their response to sea level rise than many communities along the Atlantic coast,” says Kristina Dahl, a climate scientist with UCS.
She says that by 2060, when the East and Gulf Coasts have a combined 270 to 360 communities where 10 percent or more of the usable land is chronically inundated, the West Coast may have only two or three.
But that is only a small part of a bigger picture, she says.
“Given how densely populated the Bay Area is, however, even small changes in the reach of the tides can affect many people,” she says.
In the report, the Union of Concerned Scientists has identified hundreds of U.S. communities at risk of this disruptive flooding as well as how much time remains before the flooding becomes chronic. Most are along the Atlantic and Gulf coasts.