For Every Complicated Problem There Is a Simple But Wrong Answer
There is an interesting report from the US Embassy in Thailand about dikes as a solution to sea level rise
On February 1, ESTHoff, Staff and US Embassy Science Fellow went to a well-attended presentation, "Is Bangkok Sinking?" that summarized Bangkok's subsidence history, the need for more research on cause and effect scenarios with climate change in SE Asia coastal regions, the need for a regional approach for adaptation and mitigation strategies already considered to contend with conservative future flooding scenarios, education of the general population in Bangkok to fuel political will to address the problem proactively.
Dutch Professor Cor Dijkgraaf advocated a the building of a dike based on Netherland model designs in the Bay of Thailand to contain flood waters and protect the city from climate change sea level rise and storm or tsunami surges. Similar dike strategies are being considered in United States (New Orleans), South Korea, Vietnam, Indonesia and Bangladesh. Environmental consequences were mentioned as a concern but not addressed directly. Other technological concerns such as positive pumping of wastewater for treatment outside the city, mangrove reforestation to protect coastlines and technology to reverse subsidence and increase holding capacity in groundwater reserves were mentioned as interests by the audience but not directly addressed by the panel as viable long term strategies.
Comment: For Thailand, the proposed location of this dike could turn the northern portion of the Gulf of Thailand into a freshwater lake, encompassing the important tourist resorts of Hua Hin and Pattaya. Shrimp and other fisheries would be devastated and commercial shipping affected if not strangled. The billions of dollars price tag would significantly divert resources from other infrastructure priorities. BMA officials noted that the dike is only one scenario under consideration but other ideas are few. This is where the USGS expertise could play a significant role in educating the Thai how diking actions have had counterproductive effects in the U.S. New Orleans and the Mississippi Delta, with its extensive rice agriculture, are arguably more analogous to the Chao Praya Delta than it is to the Netherlands, upon which the diking plan is based. End Comment.
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11 comments:
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7 cities about to sink.
A look ahead at adaptation in Bangkok. Lots of fun times to come, if you enjoy spontaneous travel under the direction of uniformed guides with megaphones.
~7,000,000,000 call Bangkok home. Talk of desperate measure is pretty understandable given that the city appears to be screwed. See maps here. Notice how many streets are essentially at sea level already?
If history's any guide the city will probably trump the countryside when it comes to the political clout to do whatever it's able to afford to save itself, no matter the impact.
Be wary of the comfy sounding option of "adaptation." Desperate tooth and nail struggle for survival is how the word unpacks.
Whoops, and that's 7 million in Bangkok! 7 billion comes later, after the fusion power and orbiting torus of monoclonal nutrient vats come online
BKK is an interesting place. The streets are filthy, polluted, crowded and fascinating. If you want to see gridlock, look no further. However, if you really want to get from point A to point B, you take a river taxi and then walk the rest of the way to your destination.
The whole city is one big impermeable surface, so it pretty much always floods during the monsoons, and then all that crap from the city streets runs off into the rivers and lagoons. It ain't pretty, but it's alive.
During the Reagan administration, a high US official said to an official from Bangladesh:
"Now you have cows. In the future, you'll have fish!"
Problems with tidal ecosystems have been solved in Holland using systems like this one:
http://nl.wikipedia.org/wiki/Oosterscheldekering
and, though for Rotterdam shipping not so much as for tidal flowers and beasts:
http://nl.wikipedia.org/wiki/Maeslantkering
These things are closed only during severe storm surges.
Not a cheap solution maybe, but certainly a solution.
The Netherlands dammed the Zuider Zee, now the Ijselmeer, to provide flood control and to build new land for agriculture.
You are a city/state/country planner, charged with coastal planning for next 100 years.
Your coast sometimes has storms.
Are the following scenarios any different for you?
1) No SLR, storm behave remains same.
2) SLR, .9-1.1m by 2100, constant rate.
3) SLR, .7-1.6m by 2100, with less certainty about the reate of change.
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1) Is relatively easy, because there is a good chance to predict erosion and storm behavior, and erect barriers as needed.
2) Here at least, you know you will need to raise dikes or pull back, and you can make reasoned choices of action versus economic life of assets. If you are going to build something with an expected life of 50 years, you may know where you can or cannot put it.
3) Is trickier. Uncertainty is not your friend. Given the range, some people will argue for one end and others for the other end of the range.
More: the Zuider Zee is an interesting case, which however differs from most of the inhabited US coastline.
1) By closing it off where they did, they greatly reduced the coastline open to the ocean. I.e., they had a 200-mile coastline, then closed that off with a 30-mile barrier.
This was pretty efficient.
2) Generally, that was not where the population was.
In the US, the closest equivalents might be to close off Chesapeake Bay (at the Chesapeake Bay Bridge-Tunnel, ~20-mile-long, but rather deeper than the Zuider Zee)) or the SF Bay @ The Golden Gate, narrow but deep.
Pumps are needed, too.
Neither of these seem likely soon.
Not least since SF and Baltimore are major shipping ports.
SF and Baltimore together then doubled are dwarfed by the Rotterdam seaport, which was for 40 years the worlds largest until Shanghai and Yokohama became bigger couple of years ago. Much of the seaport lies behind the Maeslantkering, this trapdoorsystem being the solution against storm surges while usually keeping the port open to sea.
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