Coastal cities need to rethink how they deal with rising waters San Francisco bay (Thinkstock)
Coastal cities need to rethink how they deal with rising waters
Lexile

An environmental engineer by trade, Paul Olsen has spent the last few decades helping people understand how rising seas threaten the places we live.
 
"I still use Tangier as my closer," Olsen says of one of Virginia's most notable sinking islands in the Chesapeake Bay, which is home to a historic community of oystermen and helps illustrate his point: rising waters aren't just a fear for the future. "It scares the heck out of people."
 
If that doesn't do the trick, Olsen invokes the memory of Holland Island, home to a thriving fishing community for a century until its last house succumbed to the bay in 2010.
 
"They failed to adapt, retreat or defend," says Olsen who, after almost 30 years with the U.S. Army Corps of Engineers, is helping Virginia navigate rising seas as a program director at the state's Old Dominion University.
 
In San Francisco's Bay Area, landscape architect Kristina Hill agrees on the options water-threatened communities must consider, but she might disagree on which ones are worth shoring up.
 
"I actually think what's going to happen is we're going to withdraw from a lot of places where there are small towns and vacation homes, because they won't have the capital to do big projects," says Hill, an associate professor at the University of California-Berkeley. The towns that need saving on Chesapeake Bay islands are smaller villages with populations of less than 300. According to Hill, moving earth to protect those towns isn't the best use of public funds.
 
But for population centers like San Francisco, New York City, New Orleans and Norfolk, Virginia, she adds, architects are looking to adapt their structures, "to keep developing in a way that is ready for sea-level rise."
 
Somewhere between retreating and building a giant wall to keep the waters at bay is a middle ground that acknowledges inevitably higher waters or periodically devastating storms - and builds with them in mind. In American cities dealing with rising seas, sinking landscapes and increasingly intense squalls, "transitional architecture" is one way to inhabit the treasured coastlines as long as possible.
 
The approach is already being implemented in parts of Europe.
 
In the Netherlands' port city of Rotterdam, architects have begun building ultramodern homes on pilings in ponds. Rather than displacing water with new construction and exacerbating flooding, the new homes are accessible by earthen berms that create a honeycomb-like pattern of water-absorbing ponds.
 
HafenCity, in Hamburg, Germany, is recruiting residents to modern apartment buildings. Instead of shielding the buildings from storm surges, architects designed them with parking garages on the first floors. Elsewhere in the city, they placed costly assets like metro stops on higher levels. Parks feature few trees and sturdy playgrounds built to withstand gushes of water during heavy rains.
 
"They call this 'tiered development,' because it's set up in vertical layers," Hill explains. "There's a layer that can be flooded, one that's protected and only in a huge emergency would be flooded and then a layer that would never be flooded."
 
Though such water-minded cities look futuristic, the concept of structures built to withstand intermittent flooding isn't new. David Waggonner, president of New Orleans-based Waggonner & Ball Architects, says that's how residents of the Bayou used to build their homes, too.
 
"Maybe it rained hard, but if it was masonry at the bottom and your principal living areas were above that, you could live on," Waggonner. "You can learn a lot from the past, the way people built."
 
In response to the devastation of Hurricane Katrina in 2005, New Orleans and the federal government built an even bigger floodwall to defend the city. Waggonner says residents still would be wise to have a backup solution for the water.
 
"You need to know where you're building, what the landscape is and has been," says Waggonner. Otherwise, "you're working against it."
 
Cities in tidal areas and near flood-prone tributaries need to make room for rising water in ways both new and old if they want to continue living there, says Hill.
 
She sees solutions like New Orleans' floodwall as "a dumbing down of the human ability to track and respond." She prefers solutions that encourage cities to work within their natural settings like those in HafenCity and Rotterdam.
 
Hill says many American cities will require a mix of defensive and adaptive structures to endure higher waters. One natural line of defense in a city's arsenal is its wetlands.
 
In San Francisco's Bay Area, wetlands are a subject of debate. Some argue that the development and highways that have filled them in over the years should be removed, returning marshes to their natural state.
 
Wetland restoration projects in northern parts of the Bay Area have already returned thousands of acres of former industrial salt ponds to marsh habitat. But imagine San Francisco's iconic coastline highway giving way to lush bay grasses and fishing egrets, along with the city zoo and multi-million-dollar Sunset District homes.
 
Even after a city concedes that it already built where protective wetlands once were, "it's difficult to pull up stakes and allow a wetland to take over," says Hill.
 
It's especially difficult to pull up stakes when they involve national assets like shipping ports and the world's largest naval base, as in Norfolk. The Hampton Roads region where Olsen and these landmarks are based has seen water levels rise 14 inches since 1930.
 
Olsen is preparing for a future in which some of the naval base's piers will be abandoned. They may be rebuilt elsewhere and the Navy will have to double down on protecting the rest. The roads that carry military personnel to their vessels will need to be raised above flood levels, and some homes will need to be built on pilings or with flood vents to minimize damage to their foundations.
 
If those waters continue to rise at a rate of six millimeters per year, the base and surrounding area will need to prepare for another foot of water in the next century.

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CRITICAL THINKING QUESTION
Why wasn't this an issue before?
Write your answers in the comments section below


COMMENTS (10)
  • alexandriap-edg
    6/20/2016 - 03:24 p.m.

    I don't think this was a problem before because no one ever thought sea levels could or would get this high or that it would be an issue and now they realize they have nothing to protect them because of the small size of these cities

  • oscarl-edg
    6/20/2016 - 03:28 p.m.

    perhaps in the future we will make cities underwater,maybe San Francisco may be the new Atlantis

  • toddg-edg
    6/28/2016 - 12:18 p.m.

    I wonder how long before other coastal cities like near the south east to be effected by rising water. And why haven't we been looking into this more earlier?

  • TaylorSeifert-Ste
    7/31/2016 - 11:56 p.m.

    Rising water levels were not an issue before because the sea level did not start significantly rising until recently. Years ago, greenhouse gases were not being emitted into the air at the rates they are now. The greenhouse gases, pollution, waste, etc. of the modern world are causing global warming to become a very big issue, which in turn is causing glaciers and ice at the poles to melt and raise water levels.

  • metau-cel
    8/08/2016 - 10:46 a.m.

    Flooding and coastal rising were never an issue before because I feel the states were rising and being conceived so that was the main focus. People are constantly focused on making more and the creation of new things so rising waters were never in the picture. The main focus wasn't on what is happening but on what is going and needs to happen.

  • johannaw-cel
    8/15/2016 - 10:17 a.m.

    I didn't know that rising waters is such a big problem and that some city have to think about how to deal with it. Maybe some city will not exit anymore in the future... The article was really impressive, frightening and interestIng to see some solutions of a few city.

  • johannaw-cel
    8/15/2016 - 10:24 a.m.

    I didn't know that rising waters is such a big problem and that some city have to think about how to deal with it. Maybe some city will not exit anymore in the future... I already was a few times in Hamburg (Germany) and I never thought about the problem with the rising water and that they already built some houses with a new architecture, the "tiered developement".
    The article was really impressive, frightening and it was really interesting to see some solutions of a few city.

  • zakrym-ste
    10/14/2016 - 12:59 p.m.

    I never thought sea levels will get this high. They have nothing to protect them because the cities are so small. I think there will be a new underwater city.

  • vaneises-
    5/31/2017 - 08:37 a.m.

    This wasn't an issue before because people were focused n other things and sea levels were never this high before.

  • juliac-kut
    6/05/2017 - 07:29 a.m.

    I thought this was very interesting. I didn't know there are a lot of islands in danger because of rising waters

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