IDENTIFICATION OF TSUNAMI PROTECTION PARAMETERS IN LOCAL MUNICIPALITY AREAS
(Case Study Areas: Pulau Pinang, Sg Petani and Langkawi)

ABDUL RAHMAN AYUB,
ANAS IBRAHIM,
SHAHREENA MELATI RHASBUDIN SHAH
Faculty of Civil Engineering, UiTM Pulau Pinang

INTRODUCTION 

According to the Malaysian Meteorological Services Department (MMSD), the first Malaysian tsunami early warning buoy that was employed on 30th. December 2005 near Pulau Rondo Indonesia will be able to give Malaysia an hour’s notice should a tsunami occur in the Indian Ocean. The data from the buoy will then be transmitted to the Earthquake and Tsunami Early Warning Centre located at the MMSD’s office in Petaling Jaya, Selangor via satellite link. The early warning information has to be transmitted to the public as soon as possible once the information about the tsunami was received by the Tsunami Early Warning Centre

            Apart from the early warning system, the existence of coastal protection parameters should be taken into account in anticipating the impact of the strong waves. In case of a tsunami detected in the Indian Ocean, potential affected areas will be warned of the approaching strong waves and how long it will take to travel to travel to those areas.

            However, before any tsunami warning can be issued, those potentially affected areas must be identified so that unnecessary panics will not occur in unaffected areas. Risk assessments for tsunami potentially affected areas must be exercised far ahead of any occurrence of tsunami. 

            In this study, coastal protection parameters are defined as the parameters of the coastal protection barriers or structures that can reduce the impacts of the strong waves or tsunamis.  Coastal protections barriers or structures can be in natural or artificial forms. Natural coastal protection barriers commonly found in Malaysian coastal are in the forms of islands, sand banks, corals/reefs, coastal hills and mangroves. Artificial coastal protections are the breakwaters, earth bunds, coastal concrete or stone walls and flex slab. 

RESEARCH QUESTIONS

It is the aim of this paper to relate the coastal protection parameters such as the location, size, length and height to the effects of tsunami as mentioned in the following hypothesis: 

Hypothesis 1

Availability of the coastal protection barriers in the tsunami prone areas had reduced the effects of the strong waves or tsunami. 

Hypothesis 2

Disturbance to the natural coastal protection barriers will expose the coastal population and facilities to direct impacts of the strong waves.

LITERATURE REVIEW

According to a report by UN Environment Programme (UN-EP), corals and mangrove protect coastlines from erosion caused by storms. However, the report said it was unclear whether they had shielded Indian Ocean coasts overall from the disastrous tsunami on Dec 26, 2004. One main purpose of preserving the natural barriers was that it provided the livelihoods for millions of people along the coasts.

            In a report published by Utusan Malaysia on 28^th January 2005, mangroves in Pichavaram village in South India was the main factor in preventing the tsunami from destroying the village. There was no casualty among the people of the village which was located 100 to 700 meters from the coastline. In this case, apart from providing protections from the impacts of the tsunami on the village, the mangroves also provided sources of livelihood to the people of the village.

            Midun (1988) stated that the natural process primarily responsible for coastal erosion is driven by waves. Coastal erosion was one factor which increases the probability of coastal area being subjected to the effects of tsunami. Along the west coast of Peninsular Malaysia, most of the agricultural land was seriously threatened. Bunds which serve to keep seawater out of the agricultural lands were affected by erosion resulting in the seawater travel as far as 2 km inland. Impact of the tsunami on those areas will surely damage the agricultural lands, houses and facilities.

            Another report by Utusan Malaysia published on 2^nd February 2006 stated that mangroves were similar to sponges with their ability to retain water and reduce floods. In case of big waves such as the tsunamis, mangroves will act as a barrier to reduce the strength of the waves

            According to a statement by the Indonesia Environmental Watch Group, the mangroves area which were threatened by the development of coastal farmland for agricultural projects before were completely destroyed during the Dec 26 tsunami. A warning issued by the group stated that any further development of coastal agricultural projects in tsunami prone areas will subject the area to the same disaster as in the Dec 26 tsunami.

            The Environmental Group also stressed that the population in the tsunami affected areas should not be allowed to reconstruct their houses and should be relocated to areas further from the coastal fronts. During the tsunami, the sea water had travelled as far as 500 meters inland and damaged the dwellings, agricultural lands and facilities in those areas. The affected areas should be allowed to grow into green areas so that it will help reduce any future strong waves’ impacts

            Jackson (2002) stated that for beach protection to be effective, it requires the adaptation of parameters such as the length of the structure, the distance off shore, the crest height and the general orientation of the structure according to the wave climate.

            A report by Geosciences Australia stated that risk assessments should be performed in tsunami prone areas long before the actual tsunami happens. An area that may be vulnerable to tsunamis need to assessed by the likelihood of an event that may cause a tsunami, the predicted location and size of the event, the shape of the seafloor where an event mat take place, the shape and location of the coastal lands that may be affected by a resulting tsunami, and the presence of any headlands or harbour in the forecasted area that may cause the tsunami to change direction.

            Location of populated areas along the coast is also a very important factor to consider in reducing the impacts of the tsunami disaster. Coastal hill should not be disturbed or subject to development since it serve as shelter for populated areas behind it. it.

Existence of islands, breakwaters, coral reefs or sandbanks in the path of a tsunami may reduce the strength of the tsunami or may change its direction. The coastal structures such as the earth embankments (bunds), concrete or stone walls and flex slab also help reduce the impact of the strong waves on the shores.

            A statement on 13^th March 2005 issued by the Malaysian Minister of Agriculture, Tan Sri Muhyiddin Yassin, stated that the protection of critical habitats such as mangroves and coral reefs is very crucial since they will serve as buffer zones for a natural disaster such as tsunami.

COMMON COASTAL PROTECTION BARRIERS IN
NORTHERN STATES OF MALAYSIA 

Breakwaters (Wave-breakers)

Breakwater is man-made structure constructed off-shore. The purpose of the wave-breaker is to reduce the impacts of the direct waves due to tsunami or due to any other types of strong wave. Breakwaters are able to protect a long shore line and to keep wave velocities away from the coastal areas. On good example of a good breakwaters structure is located in front of the Langkawi Airport in Kedah Malaysia.  

Loose Rocks Protection Layers (Rock Armouring)

Loose rocks are used in reducing the direct impacts of strong waves onto the shore. As mentioned by Schiereck (2001), the loose rocks are able to dissipate the hydrodynamic energy due to the waves. Apart from shore protections, loose rocks can also be used in dike revetment. 

Coastal Hills 

Coastal Hills is a landform on the coastal area with a distinct submits that extends above the surrounding terrain. A coastal hill can serve as a good protector against the strong waves or tsunami for the populated area behind it. During the tsunami in December 2004, there was no report of any damage or casualty in any area located behind a coastal hill.

 Natural Islands 

An island or isle is any piece of off-shore land that is completely surrounded by water. Very small islands are called islets. Also included in this category is the atoll and coral reef. The most important role that the island served during the tsunami was to deflect or to change the direction of the tsunami. 

Mangroves and Nipah Trees 

Mangroves forest is the natural vegetations of many tropical coasts and tidal inlets. The mangroves form a highly productive ecosystem and a nursery for many marine species. The mangroves also serve as a natural coastal protector from erosion and direct impacts of strong waves or tsunami. It serves as an energy dissipater and reduces the speed of the strong waves. 

Sea walls 

Sea wall is the most common form of coastal defence due to its physical barrier between land and sea. It serves as an erosion control structure and to protect the area from flooding. As stated by French (2001), sea walls also help to reduce the hydrodynamic energy from the strong waves and to reduce the speed of the waves.

Coastal Bund Revetment 

Coastal bund revetment serves to keep seawater out of the agricultural lands behind it. Beside that, it is also able to reduce the effects of the direct waves. Coastal bund is normally constructed from earth and constructed along the mangroves forests. The mangroves buffer acts as protector from the direct waves to control the bunds erosion

METHODOLOGY 

The guidelines for identifying the relationships between coastal protection parameters and the effects of tsunami as outlined in this paper, is based on a range of data. These include: 

1.      Observation of natural and artificial coastal barriers

2.      Physical measurements of the damage caused by the tsunami

3.      Interviews with local people

STUDY LOCATION 

Study location of this paper was focused mainly on Kuala Perlis, Western Coast of Langkawi, Kuala Muda in Sg Petani Kedah, and Penang. Map for Tsunami affected areas in Peninsular Malaysia is shown in Figure 1 of the appendices

DATA AND RESULTS 

In this study, the coastal protection barriers and its parameters will be identified and related to the effects of tsunami on Dec 26, 2004.  The locations of study were focused on the coastal area of Kuala Perlis, Langkawi, and Kuala Sg Muda in Sg Petani, Kedah and Penang. 

Tsunami Effects in Kuala Perlis

There was no serious impact and damage due to tsunami in Kuala Perlis coastal area.  This was due to the fact that there were quite a number of islands, including Langkawi Island, existed on the path of tsunami towards Perlis. Kuala Perlis coastal area was also protected from the waves due to the existence of bunds and mangroves along its coast.

Based on our observation, types of coastal barriers exist on this site are natural islands, mangroves and bunds. Table 7.1(a) shows the contribution of coastal protection parameters and Table 7.1(b) shows the hazardous situations due to tsunami in Kuala Perlis. 

TABLE 7.1(A):  Contributions of Coastal Protection Parameters in Kuala Perlis

TABLE 7.1(B): Hazardous Situations Due To Tsunami in Kuala Perlis

Tsunami Effects In Langkawi

The worst affected areas in Langkawi were the coastal areas in Kuala Triang, Kuala Sg Melaka and Chenang Beach.  Maximum distance of inundated area in this region went as far as 600 meter from the coastline. Damages of properties were extensive. However, there was only one casualty in Langkawi due to the tsunami. (Study map location in Langkawi is shown in Figure 2 and 3).

            Based on the observation, types of coastal barriers exist on this site are natural islands, coastal hills, mangroves and man-made wave breakers. The contributions of coastal protection parameters in Langkawi are shown in Table 7.2(a) and the hazardous situations due to tsunami shown in Table 7.2(b). 

TABLE 7.2(A):  Contributions of Coastal Protection Parameters in Langkawi

 TABLE 7.2(B): Hazardous Situations Due To Tsunami In Langkawi

Tsunami Effects in Kuala Sg Muda, Sg Petani Kedah 

The worst affected areas in Kuala Sg Muda were the villages of Kg Kuala Sg Muda, Kg Kepala Tengah, Kg Sg Meriam, Kg. Padang Salim, Kg Tepi Sungai, Kg Sungai Yu and Kg Haji Kudung. Damages to properties and agricultural lands were quite serious. There were eleven people killed in this area.  Maximum distance of inundated area in this region went as far as 400 meter from the coastline. Most of the people killed due to the tsunami were in the area where there were no mangroves and any other types of coastal protections. (Study map location is shown in Figure 4)

            Based on the observation, types of coastal barriers exist on this site are natural islands, coastal hills, mangroves and nipah trees, bunds, loose rocks and man-made wave breakers. Table 7.3(a) shows the contribution of coastal protection parameters and Table 7.3(b) shows the hazardous situations due to tsunami in Kuala Muda Kedah.

TABLE 7.3(A): Contributions of Coastal Protection Parameters in Kuala Muda Kedah 

 TABLE 7.3(B): Hazardous Situations Due To Tsunami in Kuala Muda Kedah

 Tsunami Effects in Penang 

The tsunami affected areas in Penang Island extended from the Permatang Damar Laut in the South-western District (Daerah Barat Daya) until the Gurney Drive in the North-eastern District (Daerah Timur Laut). Penang suffered the most casualties due to the Tsunami with 54 people were killed in those areas. Damages to properties were also serious. In the areas where there were less mangroves, tsunami waves travelled as far as 100 meter from the coastline. It was observed that the mangroves and nipah trees in the area have proven to be an effective wave impacts protector and absorber.

            In Kuala Sg Muda, Seberang Perai Utara, two people were killed due to the tsunami. However, the recently constructed wave-breaker in the area managed to reduce the impacts of the tsunami.  (Study map location is shown in Figure 5).

            Based on our observation, types of coastal protections exist on this site are natural islands, coastal hills, mangroves, bunds, loose rocks and man-made wave-breakers. The contributions of coastal protection parameters in Langkawi are shown in Table 7.4(a) and the hazardous situations due to tsunami shown in Table 7.4(b).   

TABLE 7.4(A): Contributions of Coastal Protection Parameters in Penang

 TABLE 7.4(B): Hazardous Situations Due To Tsunami in Penang

DISCUSSIONS AND CONCLUSION

From the study, it is shown that the availability of the coastal protection barriers, naturally and artificially, in the tsunami prone areas had reduced the effects of the strong waves or tsunami. Disturbance to the natural coastal protection barriers such as the mangroves forests and nipah trees, and coastal hills will expose the coastal population and facilities to the direct impacts of the strong waves.

            It is also shown in the study that in areas with less or no wave protection barrier, the effects of the tsunami were highly disastrous.  Most of the tsunami’s casualties were located in those hazardous areas. Tragedies resulted from hazardous situations created during the tsunami such as the river-mouths funnelling effects, escape route blockage and pocket beach disaster could have been prevented if the people were informed and educated of the early signs of the tsunami.

           An effective Early Warning System and a systematic Early Evacuation System must be established and put in place by the authorities such the Local Municipal Councils or any local government far ahead of next tsunami event.

 FUTURE RESEARCH

Plans for further researches should include preparation for the profiling of tsunami prone areas, planning for the early warning system and establishment of the early evacuation plan in the potentially tsunami affected areas. 

Acknowledgement 

The permission granted by the Director of UiTM Pulau Pinang to undertake this study is gratefully acknowledged. Deep appreciation also goes to the IRDC, UiTM for the funding of this study. Any opinion expressed is solely the writer’s and do not necessarily reflect the view of the University.