Monday, May 23, 2016

South Korea: Final Hazards Report

During the course of this semester, this class has studied various types of natural hazards -- all of which have had some effect on the Republic of South Korea.  The most devastating, however, have been the result of global climate change and its impact on the coastal regions of the country.  This report will focus on two natural hazards that are major issues today: sea level rise and typhoons.

South Korea is on a peninsula that is surrounded on three sides by seas -- The East China Sea to the south, the East Sea (Sea of Japan) to the east, and the Yellow Sea to the west.  This Asian country has 1,499 miles of coastline, with the majority of its population residing in coastal areas.  Most of its infrastructure (ports, airports, roads and power plants) is also located on the coast, and further development continues despite threats from the effects of climate change.  Specifically, climate change is responsible for a rise in sea level and is contributing to the intensity and frequency of typhoons, bringing with it huge storm surges and flooding in these high population-density areas.


Image result for map of south Korea



Sea level rise
The rate of sea level rise is higher in South Korea than the global average.  From 1964 to 2006, wave heights on the east coast of the country reached 7m as the sea level has risen by 22cm.  Since sea walls are only 4 to 5m high in most of the ports, there has been extensive damage from flooding and erosion as waves overtopped the sea walls during storms, heavy rains and typhoons.  This is a major problem on the east coast of South Korea as there are a number of sandy beaches and cities lining the coast in Gangwon Province.  Also, roads have been built along the entire shoreline allowing tourists to appreciate the local scenery. Gangneung, a tourist attraction in this area, is losing its beaches, and its coastal structures are continuously being eroded by waves, which, in turn accelerate coastal erosion by blocking the natural flow of soil and sand.

In 2015, a study was conducted to explore a design strategy for protecting the coastline of Gangneung from the effects of climate change.  The main strategy was to reconnect the pine forest and the beach.  The roads and adjacent commercial centers would be relocated away from the coastal areas through the pine forest.  The pine forest then would provide shade for the tourists and also facilitate the natural influx of soil and sand.  Since wave heights will undoubtedly increase because of rising sea levels, the forest would also act as a natural buffer.

The above strategy is an example of a retreat strategy to protect a city from sea level rise.  South Korea has been exploring several strategies as it attempts to cope with this challenge to population-dense areas at its coasts.  Generally, there are three different approaches to dealing with sea level rise.  One is protection strategy.  This is divided into two types:  hard protection (dikes and levees) and soft protection (using natural sedimentation and vegetation to form a buffer zone).  A second strategy is accommodation whereby existing infrastructure is modified. A third is retreat strategy where risk of seal level rise is mitigated by relocating the development further from the coastline.

The map below shows the areas of the country most affected by the rise in sea level.


Image result for sea level rise in south korea pictures

Typhoons
Typhoons are natural hazards in South Korea, as cyclones are a natural occurrence in the north western Pacific; however, they are increasing in intensity because of climate change.  Because the coastal areas of South Korea are densely populated, this natural hazard has become a catastrophe.  Several of note are Typhoon Sarah, which killed 669 people in 1959 and had winds of up to 105 mph; Typhoon Rusa, which killed 110 people in 2002 and had winds of 120 mph; and Typhoon Maemi that killed 100 people and left 25,000 people homeless.  Its winds were clocked at 134 mph, the highest in the country's recorded history. Typhoon Maemi is considered to be the most powerful typhoon in South Korea's history and is termed the typhoon of the century.  It leveled buildings, caused widespread flooding, washed out roads, downed electric and telephone poles, and caused tens of millions of dollars in damage in the coastal city of Pusan alone.  Cars floated down streets, cruise ships were tossed onto the beach, 82 ocean vessels sank and roads and bridges buckled.

The following video series is an up close and personal view of Typhoon Maemi.
https://www.youtube.com/watch?v=Rbk2CR-XM2g

These photos depict the devastation that Typhoon Maemi wrought.


Image result for images of typhoon maemi
Image result for images of typhoon maemiImage result for images of typhoon maemi

Image result for images of typhoon maemi

South Korea has typhoon warnings in place for its citizens.  The Korean Meteorological Administration has a website that lists typhoon information, satellite imagery and typhoon track prediction.  As typhoon intensity increases because of climate change, and as more and more people reside in high risk coastal cities, the warnings might be too little too late;  the high volume of cars will not be able to leave the areas on the existing roads.

Recommendations and risky areas
South Korea has programs in place that address sea level rise and typhoon preparedness as discussed above.  The problem, as I see it, is that the population prefers to live in high-risk areas along the coast.  Development continues on reclaimed land and landfills in spite of continuous problems with flooding, erosion, typhoon damage... And this seems to be a global trend.  The Republic of South Korea will have to address infrastructure issues such as more arteries joining coastal towns to inland highways as escape routes, relocating roads and commercial centers as proposed for the town of Gangneung, building higher sea walls and encouraging people to live in other parts of the country.

The areas of the country that are at the greatest risk of sea level rise and typhoons are the southern and eastern coasts. They are tourist areas, they have ports and commercial developments, and there are roads that hug the coast.  Protections should address these areas primarily.

If I were to move to South Korea, I would not be inclined to live near the coast.


Map of Seoul, South Korea

Soeul, the capital, would probably be my choice.  It is near a river and is close to a national park, but it is not on the coast -- although I would have to contend with Yellow Dust and sink holes!
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Works cited:
http://www.zeroco2.no/projects/south-korea
South Korea: Energy and Climate Change

http://www.scirp.org/journal/PaperInformation.aspx?paperID=57543
Scientific Research; Journal of Building Construction and Planning Research, 2015; Protecting the coastline from the effects of climate change: adaptive design for the coastal areas of Gangneung, Korea; Yumi Lee; June 2015

http://www.smh.com.au/environment/climate-change/super-typhoons-to-increase-in-strength-with-climate-change-researchers-find-20150529-ghcbfs.html
The Sydney Morning Herald; Environment; Super typhoons to increase in strength with climate change; Peter Hannam; May 2015

http://eprints.nottingham.ac.uk/2040/19/Republic_of_Korea.pdf
Department of Energy and Clumate Change; University of Nottingham; CLumate Observations, projections and impacts: South Korea; April 2011

http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=10092
Earth Observatory; Typhoon Rusa; august 2002

http://www.koreatimesus.com/s-koreas-sea-level-up-4-inches-in-40-years-data/
The Korea Times; S. Korea's sea level up 4 inches in 40 years; December, 2015

http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=6263586&url=http%3A%2F%2Fieeexplore.ieee.org%2Fxpls%2Fabs_all.jsp%3Farnumber%3D6263586
IEEExplore; Estimation of storm surge inundation and hazard mapping; Jong Joo Yoon; 2012

https://www.youtube.com/watch?v=Rbk2CR-XM2g
Typhoon Maemi hits South Korea

http://www.nytimes.com/2003/09/17/business/typhoon-hits-south-korea-economy.html
The New York Times; Typhoon hits South Korea economy; September, 2003

http://reliefweb.int/report/republic-korea/massive-typhoon-maemi-pounds-south-korea
ReliefWeb; Massive Typhoon Maemi pounds South Korea; September 2003

http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=10092
Typhoon Rusa: Natural hazards; 2002

https://en.wikipedia.org/wiki/Typhoon_Sarah_(1959)
Typhoon Sarah; 1959


Monday, May 2, 2016

Coastal Hazards and South Korea

South Korea is on a peninsula that is surrounded on three sides by seas.  To the south is the East China Sea; to the west is the Yellow Sea; and to the east is the East Sea (Sea of Japan).  This Asian country has 1,499 miles of coastline, and, because of that, it has experienced many of the coastal hazards that are discussed in the text.







Waves as a result of storm surges from typhoons have resulted in many deaths as well as beach erosion.  South Korea is hit by typhoons every year, and because of climate change, their strength and frequency are increasing, causing severe damage to coastal zones. In 2015, the high waves generated by Typhoon Chan-hom hit South Korea's port city of Busan causing considerable damage to Haeundae, the beautiful white sand beach that attracts tourists from all over the world.



Haeundae, with its over one-mile long white beach, is considered one of the greatest natural wonders of the country, but it has experienced serious erosion since the 1970s.  Since then, it has shrunk from over 70m wide to less than 30m wide.  Before the 1970s, the beach was undeveloped.  Since then however, there has been road construction, regional development including hotels and businesses, and tourist attractions.  The development was done without the benefits of a Coastal Commission to weigh the risks to the natural environment.  Consequently, the development plus the storm surges and wave-induced currents of the summer and winter storm season have resulted in the rapid erosion of the beach since its pristine condition of over 40 years ago.



In addition to waves from storm surges, rip currents plague the beach at Busan.  Each year, many people are rescued from the waters off the coast of South Korea's Haeundae Beach.  These same currents, in conjunction with strong wave-induced currents and regional development, are the major  causes of beach erosion.


Related image







South Korea has implemented many strategies for combatting the effects of coastal erosion.
(1) Shore parallel structures: Many offshore breakwaters, seawalls and revetments have been constructed along South Korea's East Coast to protect against the strong waves during typhoons.
(2) Beach nourishment: Beach nourishment was implemented as a means to stabilize the shoreline at Busan.
(3) Non-traditional shore protection structures:  Geotubes are a type of coastal structure that can be used to protect the coast.  A geotube is a geosynthetic type of material that is stitched to form a tube that is then filled with sand or cement.
(4) Shore perpendicular structures: After construction of a coastal road and seawall along Namae Beach resulted in beach erosion, construction of a short jetty and two submerged reef mounds was proposed. The goal was to reduce wave-induced currents and corresponding beach erosion.
(5) Natural resource restoration: There has also been reef degradation (whitening phenomenon) off the coasts of Korea since the 1970s.  Disappearing algae has led to a reduction of fish, abalone, and sea cucumbers. The self-purification capability of seawater has declined dramatically, and it threatens the ecological balance of the ocean -- and fish productivity.  South Korea is experimenting with steel slag to promote marine reforestation in areas where damage is significant.

Haeundae Beach has seen some specific efforts by the Korean government to restore its natural beauty.  In the 1980s, South Korea began using beach nourishment alone to replenish the shoreline.  Adding sand, however, was not enough to mitigate the damage to the beach.  A study entitled Mitigation Measures for Beach Erosion and Rip Current concluded with a recommendation that groin-type submerged breakwaters at the sides of the beach, plus large-scale beach nourishments would minimize the rip channel, thereby minimizing the wave-induced currents and rip currents that have had such a devastating effect on the beach.  South Korea has now allocated $41 million to build structures in the ocean to channel the waves and currents away from the beach.
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http://ics2013.org/papers/Paper4433_rev.pdfJCR online
Mitigation Measures for Beach Erosion and Rip Current; Kyu-Han Kim, Sung won Shin, Agnes Y W Widayati, 2013
http://repository.unhas.ac.id/bitstream/handle/123456789/7671/158.CC%2009.pdf?sequence=1
Improving the Coastal Hazard Management in Indonesia: Lessons learned from other countries; A.Y.W. Widayati, KH Kim; Sept. 2013

http://www.straitstimes.com/asia/east-asia/typhoon-makes-waves-in-south-kore

Asia; The Straits Times; Typhoon makes waves in South Korea;
https://www.dramafever.com/news/heres-the-innovative-way-south-korea-is-rescuing-its-dying-beaches/; Dramafever; Here's the innovative way South Korea is reusing its dying beaches; March 2014

https://en.wikipedia.org/wiki/Geography_of_South_Korea
Wikipedia; Geography of South Korea