Coastal Hazards in Indonesia

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                   Figure 1: This animation illustrates the power of the sea over the land.
                   (Coastal erosion at North Cove, Washington. The red line indicates the shoreline in 1990)


Coastal Hazards in Indonesia

Indonesia has more than 17,500 islands with a total shoreline of approximately 80,000 km. The coasts are the most dynamic areas in this Southeast Asian nation as these are very strategic locations with many natural resources for human livelihood.  Majority of the coastal population subsists on fishing and to a greater extent beach tourism.
 
Many large cities with dense population such as Jakarta, Semarang, Surabaya, are located in coastal areas. Indonesia’s coastal areas have geomorphologically complex processes including coastal environmental degradation due to natural hazards (Figure 2). 

                                    
                                        Figure 2: Coastal dynamics, geomorphological processes and 
                                                        natural hazards of Indonesian coastal areas

How Coastal Erosion Works Video 

https://www.youtube.com/watch?v=B08iDMXYtR8

            

Coastal Erosion in Indonesia Explained

Coastal erosion is a natural phenomenon occurring in coastal areas where land along the coastline is displaced due to the waves, tides, currents and wind, among other factors. In ideal conditions, such land is replaced by the same amount of sediment eroded from other areas in what is called accretion.

However, this natural balance is not occurring on Flores Island as well as other regions in Indonesia.  The northern coast of Java Island is one of the areas that has been affected most by erosion. In terms of provinces, the three most affected regions are Central Java, East Java and Southeast Sulawesi.

While rising sea levels due to climate change have become a factor in land loss, environmental damage has also made the coasts more vulnerable. Furthermore, local factors might have played a greater role in erosion than global factors.  The rising of sea levels due to global warming have contributed to erosion in some regions.  However, the disruption in the local coastal landscape plays an even bigger role in worsening the phenomenon.

Erosion had worsened in the last several years as more people cleared coastal mangrove forests to make space for milkfish ponds.

Erosion along the western coast of Demak, Central Java, over the last 20 years caused three villages - Bedono, Rejosari and Timbulsloko - to sink into the sea. Experts said the abrasion in the area, considered among the worst in the country, was due to the construction of ports and industrial projects including land reclamation.

In Southeast Sulawesi, rampant mining has been blamed for environmental destruction in the islands in the northern part of the province. There were reports of abrasion due to rampant illegal sand mining at Siontapina Beach on Buton Island.


Mitigation Measures

Indonesia, the world's largest archipelagic nation, is losing its coastal areas due to rising sea levels and unsustainable economic activities.  According to a study from the Maritime Affairs and Fisheries Ministry, the country loses around 1,950 hectares of coastal area - an area equivalent to Padang Panjang, a city in West Sumatra - annually due to erosion. Only 895 hectares of new beach land is formed every year from natural sedimentation.

In the last 15 years, the country has lost 29,261 hectares of coastal area, which is about the size of Jakarta.

Realizing the current health condition of its coasts, the government of Indonesia has initiated mitigation measures to combat this problem.  These include:

  • conducting shoreline monitoring to observe the dynamics of coastal erosion
  • construction of dikes and seawalls to block the tide and wave action
  • using artificial reefs to break the action of waves prior to hitting the coasts while at the same time serving as sanctuaries for marine life
  • strengthening the coordination among governmental agencies to cope with the issue of coastal erosion
  • implementing mangrove replanting projects to revitalize the eroded coastal land by holding the sediment material and reducing the wave energy
  • enhancing the engagement of community participation in mitigation actions by increasing the people's environmental awareness to boost their participation in various community-based management plans

References

http://journalarticle.ukm.my/2355/1/1.2011-3-MARFAI_ugm-english-1%5B1%5D_-_edited_28.8.pdf

https://www.straitstimes.com/asia/se-asia/indonesia-has-lost-land-equal-to-size-of-jakarta-in-last-15-years-due-to-erosion


Photo Credits:

https://www.nwnewsnetwork.org/environment-and-planning/2018-05-22/new-hope-to-stop-or-greatly-slow-seemingly-unstoppable-shoreline-erosion

https://www.researchgate.net/figure/Coastline-change-due-to-coastal-erosion-in-Terboyo-Kulon-North-Semarang-after-Irwani-et_fig2_288596329


















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