The Great Flood
Apr 03, 2014 12:15PM ● Published by Cate Reynolds
Amy Owsley has devoted her career to the Chesapeake Bay. As deputy director of the Eastern Shore Land Conservancy, she travels widely in the region and talks extensively with Eastern Shore leaders.
In 2005, Owsley began noticing a pattern of persistent flooding in certain areas. Last year, the nonprofit conservancy decided to make the rising sea level a planning priority. “We want to initiate a conversation about it,” says Owsley.
So far, results have been mixed.
In towns like Oxford and Chestertown, which have experienced increasing flooding over the years, officials and individual property-owners have taken the initiative to find a solution.
“There’s a wholesale engagement of the community,” Owsley says of places like Dorchester and Talbot counties, although she finds much less interest in the Upper Eastern Shore, which hasn’t experienced the same conditions.
At least, Owsley is encouraged, “when there is a conversation, it’s not is this happening but what can we do about it?”
In 2013, Gov. Martin O’Malley kicked off a blitz of doomsday stories, telling of disappearing land, an endangered seafood industry, and underwater landmarks. He followed up with two call to action, dealing with climate change, aka global warming.
In July, he issued the state’s greenhouse gas reduction plan, the goal to reduce emissions by 25 percent by 2020; and, in December of the previous year, an executive order that state agencies consider sea level rise and coastal flooding in their capital projects.
The actions were based on recommendations from the Maryland Commission on Climate Change, including a panel of sea level rise experts that came up with impact assessments in 2008 and updated in 2013.
Ming Li is a member of the current panel. A professor of oceanography at the University of Maryland Center for Environmental Science, Li’s specialty is the effect of climate change on coastal oceans and estuaries like the Chesapeake and Delaware bays.
The stories played up the panel’s estimate of an up to 2.1-foot rise in sea level by 2050. As scary as that sounds, it is only one figure in a complicated scenario that involves local factors like land subsidence (the scientific term for sinking land) and global trends like climate change, melting glaciers and polar ice caps, and warmer ocean temperatures.
Li says the panel gave the governor two estimates for average sea level rise in Maryland:
By 2050, average sea level rise will be 1.4 feet, ranging from a low of .9 feet to a high of 2.1 feet. By 2100, the average sea level rise will be 3.7 feet, from a low of 2.1 feet to a high of 5.7 feet.
Li says the sea level rise in Maryland is going faster than earlier predictions for two reasons: the panel’s 2008 projection was too conservative and emerging evidence of more rapid polar ice melt than expected.
Moreover, Maryland’s sea level rise is twice as fast as the worldwide average because of land subsidence, says Li, who works out of UMCES’ Horn Point Laboratory in Cambridge, and whose research is funded by the U.S. National Oceanic and Atmospheric Agency and the National Science Foundation.
As a result of the higher average sea level, high tide is getting higher. Li says the tidal range of the Chesapeake Bay region, particularly the Upper Bay and tributaries from Annapolis to Baltimore, could increase by one-half to one foot by the end of this century, in addition to the rising sea level.
Storm surge—the height of waves during storms and hurricanes—is getting higher and coastal inundation—the area flooded by a storm—broader as well. 2003’s Hurricane Isabel, one of the century’s most destructive so far, had a storm surge of six feet; in 2050, the same storm’s surge could reach eight feet.
“Sea level rise is gradual so you don’t necessarily notice it. Storm surges get people’s attention,” says Li.
Evidence points to more frequent and more destructive storms and hurricanes because of the warmer ocean temperature. “You can’t blame all storms on global warming but there is recognition that warm water feeds into the intensity,” he says.
In the 1950s, the east coast experienced nine major storms and five hurricanes off the Atlantic Ocean. The average now is 15 major storms and nine hurricanes. Li cites Hurricane Sandy, in 2012, which flooded hundreds of homes and businesses on the Eastern Shore.
“Maryland didn’t get the publicity New Jersey and New York did,” he says, “but it caused a lot of damage.”
Li is currently developing a computer model that, he hopes, will help local officials with building regulations and housing heights. The model anticipates future storms and simulates their effects. Using Google Earth and weather and water data at that time, the model accurately predicted what, in fact, happened on the Eastern Shore during 2011’s Hurricane Irene.
“We want to make the model available for government officials, but it’s up to them to take action,” he says.
Recently, the City of Annapolis initiated a conversation about sea level rise and what it means for the City Dock and Eastport neighborhoods. Frank Biba, the city’s chief of environmental programs, spoke at the public meeting.
Armed with a 2011 city-commissioned study, Biba talked about a sea level rise of between six inches and 16 inches by 2050. The figures were derived from various resources, including a U.S. Army Corps of Engineers analysis following 2003 Hurricane Isabel that flooded U.S. Naval Academy basements where electronic equipment is stored.
With a six-inch sea level rise (the lowest prediction), City Dock and Eastport will be flooded in a storm. “Even now, the two flood during high tide events,” Biba points out.
The city’s study includes recommendations for structural methods like levees, seawalls and pumps, and non-structural methods like elevation, relocation, demolition, and reconstruction of City Dock. For some structural methods alone, the cost was estimated at $3.7 million.
The situation is complicated by land ownership, financing arrangements and federal and state permitting. “You have to get the private property-owners on board,” says Biba.
In any case, plans for the City Dock and Eastport have neither been approved nor funded. If the city’s study is any indication, it’s not going to be easy, quick, or cheap.
The same can be said of state and federal efforts to mitigate sea level rise.
The state department of natural resources is taking the lead in communicating with the public on the issue. There are numerous plans—they are comprehensive and cover everything from sea level rise and storm surges to chronic erosion and sinking land, says Zoe Johnson, manager of the department’s Office for a Sustainable Future.
A taste of what’s involved is found in O’Malley’s greenhouse gas plan, where one chapter details multiple strategies involving several different state agencies but without cost estimates attached.
Greenhouse gas is a worldwide issue and “even if Maryland reduces emissions per our plan, we will still have the same projected sea level rise this century,” says Johnson.
The Chesapeake Bay region’s geological conditions place it third, after Louisiana and southern Florida, among the most vulnerable areas in the country for the effects of sea level rise.
So far, state plans for sea level rise “are not documents that give structural solutions. They are locations to places,” says Johnson. “That’s the next level, from planning to implementation.”
Johnson mentions a few solutions, some of which are already state policy. Restricting or prohibiting development in vulnerable areas is one. Others are revising building codes to take flood level into account; protecting existing infrastructure; expanding buffer zones like forests, wetlands and beaches; and the Coast Smart Communities Initiative of grants to local governments.
Overall, Johnson doesn’t have an estimate of cost. Some solutions will be costly. Others will be done by local governments. “At this point, there are too many variables to quantify,” she says.
Another possible solution—though highly unlikely for, at least, several generations—involves the building and implementation of water desalination plants (which covert saltwater into drinkable water). Several Arab nations have such systems in place because their freshwater resources are extremely limited. Both California and Arizona have also begun discussion of utilizing such systems for the same reason. However, water desalination is extremely cost prohibitive. Arizona estimates the cost to build a desalination system piping in seawater from the Gulf of Mexico at $250 billion. Desalination also requires massive amounts of energy and, to date, there is no data to suggest that the amount of water removed from the Bay watershed and desalinated would offset sea level rise. Though not in the discussion presently, water desalination could be worth exploring in the future.
On the federal side, the U.S. government is looking to the states to take the lead in responding to climate change, according to Lewis Linker, environmental scientist with the U.S. Environmental Protection Agency’s Chesapeake Bay Program, headquartered in Annapolis.
Linker credits Maryland with taking the initiative on land use, pointing to O’Malley’s greenhouse gas reduction plan as an example.
Says Linker. “We are just beginning to adapt to climate change and find ways to mitigate it.”