SOURCE: New York Times

DATE: March 7, 2018

SNIP: A new report suggests that sinking land, known as land subsidence, will increase the potential reach and damage of flooding in the Bay Area, submerging a larger portion of the region by the year 2100 than previously estimated.

Subsidence can be caused by groundwater pumping, which can act to “deflate” the ground above it or the gradual compacting of landfill — when lands are filled in an effort to create solid ground to build upon.

The authors of the report — Manoochehr Shirzaei, a professor at Arizona State University and Roland Bürgmann, a professor at University of California, Berkeley — have combined land elevation data with rising sea level projections. And they are now challenging the current flood threat projections as too conservative.

Under the new projections, San Francisco International Airport could see half of its runways submerged by the year 2100. Original estimates that did not include land subsidence were much lower. Other areas around the Bay that have been built on engineered landfill, like parts of Foster City and Treasure Island, are particularly vulnerable to the dual impact of subsidence and sea level rise.