Chesapeake Bay residents can breathe a little sigh of relief. The magnitude of absolute sea-level rise, the volume and mass of sea water, happening along its coastlines is a mere fraction of the global average, according to a new study. That’s a break the highly populated coastline needs because the other half the study shows that the land around the Chesapeake is sinking, a lot.
New research led by John Boon with the Virginia Institute of Marine Science (VIMS) found that absolute sea-level along the Chesapeake Bay is rising on average 1.8mm per year, about 50 percent of the global rate. “The bad news,” said Boon in a press release, “is that local subsidence more than makes up for it.”
Development and land use practices, such as increased population and groundwater withdrawals, are putting the pressure on the Chesapeake, literally causing the land to sink. In fact, the land is subsiding so much that it leads to an overall picture of sea-level impacts that outstrips many other regions around the world, said the study.
On average, relative sea-level rise – the amount of water rise in relation to land – for the Chesapeake is between 2.91 and 5.8 millimeters per year. To put that in perspective, either of those values is higher than the highest rates recorded for many other places, according to the press release. And while, 5.8mm per year might not sound like much, this adds up to about a 2-foot rise over the course of 100 years.
This is especially important news for Bay communities already threatened by increased flooding hazards from hurricanes and Nor’easters, said the study. Boon encourages further monitoring and mapping of sea-level trends that could aid in the adjustment of emergency response plans.