The causes
Coastal erosion is the loss of land due to a landward movement of the beach or shoreline. Over the latter half of the last century natural coastal processes have caused a general landward retreat of the beach around most of Kosrae. Over this period, the rate of this retreat has been significantly exacerbated by human activities.
Kosrae's Coast
Reducing coastal hazard risks on Kosrae
coastal erosion
Whilst natural factors have influenced changes in Kosrae's coast, it is human influences, particularly over the last 40 to 50 years that has significantly exacerbated coastal erosion.
These effects are directly linked to the rapidly increasing population, development and changes in construction practices, such as increasing use of cement. The most detrimental practices have included:
The most significant of these impacts has been the removal of coral rubble from the outer reef flat for sub-base for the road, construction of the causeway and other development projects.
Although much of this removal was conducted between ten to forty years ago, these effects are still causing changes at the coastline.
Despite considerable opinion concerning the construction of the airport, this has not been responsible for the erosion evident around Kosrae other than the severe erosion that occurred in the immediate vicinity of Tafunsak village associated with the dredge pits.
Furthermore, the closure of the Insrefusr Channel has not been a dominant cause of the erosion at Finaunpes. Re-opening the channel will not stop the erosion problems along the Sandy Beach coastline
These effects are directly linked to the rapidly increasing population, development and changes in construction practices, such as increasing use of cement. The most detrimental practices have included:
- Removal of coral rubble from the reef.
- Removal of sand and cobbles from the beach
- Dredging of the reef flat at Tafunsak.
- Altering the position of river outlets or changing swamp drainage patterns and flows.
- Building inappropriate coast defenses and land reclamation.
The most significant of these impacts has been the removal of coral rubble from the outer reef flat for sub-base for the road, construction of the causeway and other development projects.
Although much of this removal was conducted between ten to forty years ago, these effects are still causing changes at the coastline.
Despite considerable opinion concerning the construction of the airport, this has not been responsible for the erosion evident around Kosrae other than the severe erosion that occurred in the immediate vicinity of Tafunsak village associated with the dredge pits.
Furthermore, the closure of the Insrefusr Channel has not been a dominant cause of the erosion at Finaunpes. Re-opening the channel will not stop the erosion problems along the Sandy Beach coastline
In this section:
- Coastal erosion
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(C) Doug Ramsay & KIRMA, 2008
A factor influencing coastal change on Kosrae over the last 100 years has been the pattern of typhoon and major storm activity.
Typhoon events during the 1800’s and three events between 1890 and 1905, whilst causing much damage to the island, also played a significant role in influencing the position of the coastline, particularly along the Lelu and Malem coasts, over the last century by:
Typhoon events during the 1800’s and three events between 1890 and 1905, whilst causing much damage to the island, also played a significant role in influencing the position of the coastline, particularly along the Lelu and Malem coasts, over the last century by:
- Depositing large volumes of sand and coral rubble from the coral reef onto the reef flat which in turn supplied sand and coral to the beaches allowing them to maintain their position or build out.
- Developing banks of coral rubble on the outer reef and shingle ridges on the reef flat which provided greater protection to these beaches from waves, and provided a suitable habitat for shoreline mangroves and seagrass areas to develop on the inner reef flat on sections of the coastline where they would normally not be found (e.g. the Malem coast).
- Resulted in an insufficient supply of beach sands and cobbles to maintain the seaward position of the shoreline that had developed, resulting in a landward retreat over the last 50 or so years (and which is still ongoing) to a more stable position.
- Reduced the level of protection provided by the coral rubble (as it is gradually broken down) over the reef flat in reducing wave heights travelling over the reef flat towards the shoreline.
A lack of typhoons
Human impacts
