THE WORLD’S COASTS: KELANTAN, MALAYSIA

7/21/2019 THE WORLD’S COASTS: KELANTAN, MALAYSIA

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This web version is an unedited version submitted to Eric Bird of Geostudies. Some of theillustrations have been enhanced.

The World's Coasts: ONLINE

19 South East Asia

19.2 MALAYSIA19.2.11 Kelantan

Teh Tiong Sa and Yap Hui Boon

THE WORLD’S COASTS: KELANTAN, MALAYSIA

INTRODUCTION

Kelantan, with a coastline length of 71km, is the shortest among the east coast states ofPeninsular Malaysia (KN 1). It shares a state boundary with Terengganu, unique in Malaysia,as the boundary does not follow a river course, and an international boundary with Thailandalong Sungai Golok. The Kelantan coast, which is wholly sandy, forms the outer edge of theKelantan coastal plain, built up by deltaic, marine and swamp deposits. The coast,unprotected by headlands or offshore islands is completely exposed to waves from the SouthChina Sea, has a concave sector at Sungai Semerak, a protrusion at Pengkalan Datu and anirregular coastline of deltaic islands, spits and a lagoon at Tumpat. The low-lying coastal

plain is very wide, composed of a 10km outer belt of barrier and deltaic deposits backed by a30km wide alluvial plain whose surface is often interrupted by abandoned levees andmeander scrolls. The surface morphology, especially the distribution of beach ridges, have

been independently mapped by various researchers, one of the earliest being Swan (1968).The coastal alluvium is deep, attaining more than 100m along the outer edge of the plain. A15m deep unbottomed borehole near the beach records an upper layer of sand, succeededdownwards by sandy clay and clay. The sands were iron stained and unsuitable for glassmaking. The common heavy minerals were ilmenite, amphibole, tourmaline, magnetite,zircon and rutile. Pyrite and foraminefera, commonly pyritised, increases with increasingdepth (Chu 1975).



KN1 Background map of Kelantan

Over 70% of the coastline is in retreat (EPU 1985). Severe erosion is taking place along theold delta front at Pengkalan Datu and a westward elongating spit extending from the presentSungai Kelantan has linked up with the mainland trapping a large lagoon behind it (KN 2).The spit is disintegrating along its eastern portion, allowing big waves to enter the lagoon.

Processes of erosion and sedimentation along the coast are in delicate balance, and thatretreat of the coastline in several places is counter balanced by accretion of land elsewhere(Koopmans 1972).

KN2: Tumpat spit and lagoon



Massive breakwaters for flood mitigation purposes have been constructed at the mouth of allthe major rivers or at newly created river mouths. The opening of river mouths is part of theflood mitigation programmes and also to facilitate the movement of fishing boats, and insome cases new channels have been dredged to shorten rivers and speed up the discharge of

floodwaters into the sea (KN3). The need to open up the river mouths is illustrated by a proposal in 1988 to dredge a total of 1.67 million cubic metres of sediments from eight rivermouths in Kelantan.

KN3: Dredging of new channels to shorten rivers for flood mitigation purposes

COASTAL SETTING

The tides at the standard port of Getting (Tumpat) are mixed, with the diurnal component

dominant. The ratio between diurnal and semi-diurnal tide is 1.5:1; diurnal inequality is highand often there is one low water in a day (Toyoshima 1994). The maximum tidal range is1.2m and the mean spring tidal range of 0.6m is the lowest recorded in Malaysia(Hydrographic Directorate, Royal Malaysian Navy 2003). During the northeast monsoonthere is a rise in sea level by up to 40cm, due to water stowage.

Sungai Kelantan is a major sand supplier and numerous sand islands lie within the channels.It has been estimated that during the last 100 years there has been a 40% increase in sedimentyield due to basin activities to the present 1.7 million cubic metres per year (ENEX 1977).Sediments from the banks of Sungai Kelantan are generally sandy: the gravel, sand and silt-clay content vary from one environmental setting to another (Zakaria 1972). Large quantities

of sands are dredged from the river for the construction industry. The estimated netlongshore transport along the abandoned delta coast is 73,000 cubic metres per year along



the Pengkalan Datu-Sabak coast and 778,000 cubic metres per year along the Pantai CahayaBulan-Kuala Besar coast (EPU 1986). The figures given for the various sectors suggest that29,000 cubic metres of sands are eroded from the Sabak beaches. There appears to be two

breakpoints (zero point drift) in the net littoral drift along the Kelantan coast. The first islocated between Sungai Besar and Sungai Kemasin and the second between Kampung

Cerang Ruku and Sungai Semerak. Coasts facing north would have a northwestward littoraldrift and east facing coasts would have a southeastward littoral drift (DHL 1984). Theconvergent drift towards Sungai Semerak will slowly fill in the concave section of the coast.The rate of spit elongation westwards has been estimated at 207m per year for Tumpat spitand 55m per year for Sungai Kemasin, and the southeastward spit elongation for SungaiSemerak is 30m per year (Raj 1982). However, like all east state coasts there is a strongseasonal nature of wave approach and hence different drift directions and rates of sedimenttransport may be observed throughout the year.

QUATERNARY GEOLOGY AND EVOLUTION

Kelantan has a wide coastal plain built up of continental deposits along its inner margin andmarine deposits along its outer margin (KN 4). The depth of the alluvium exceeds 100m inthe inner portion of the coastal plain and the deposits form an important source of groundwater in Kelantan. There are a few scattered granite hills at Gunong Panchor. The coastal

plain can be divided into a southern and northern sector, which begins north of GunongPanchor. Permatang deposits with intervening infilled lagoons dominate the southern sector.The older series are composed of broad ridges separated by elongate depressions occupied byfresh water swamps and the younger series is a continuous belt composed of closely spacingridges. Meandering rivers occupying the depressions have reshaped the inner margin of eacholder permatang series. The orientation of the older series does not run parallel to the presentcoastline or to that of the younger series, but converges towards them in the southerly

direction. In the northern sector near to Sungai Kelantan, most of the older series are absent,having been destroyed by fluvial activities or buried beneath recent sediments. An exceptionis the older series preserved in the Tumpat area.

KN4: Quaternary geology and background map of Kelantan



Sediments in the Kelantan coastal plain were laid down about two million years ago at a rateof about 130,000 cubic metres per year (ENEX 1977). The present delta formation, however,is believed to date back only some 6,000 years ago. The present delta form made up of anabandoned cuspate delta at Sungai Pengkalan Datu and a modern fan shaped delta at Sungai

Besar has been recognized by various researchers, but the year of shift is unknown. Variousdates have been proposed, but there is little scientific basis for the dates advanced. Study ofold small-scale maps has not helped either; as such maps are not very reliable. More detailedinformation has to be gathered before any definite conclusion may be drawn (DHL 1984).The sequence of delta evolution associated with shifting river mouths shows a westerlymigration of the Sungai Kelantan (KN5).

KN5: Evolution of the Kelantan delta

The lithostratigraphic section in Bachok, constructed from six cores, shows that behind theyounger permatang series, the lithological units showed a back-barrier alluvial clay above a



lagoon and marsh fringe silt-clay and possible buried barrier sands lying at –0.5 to –3.0m(KN 6). The core on the permatang penetrated barrier sands, channel clay, lagoon/marshorganic sand and clay and a reverse graded marine, shelly sand, silt and clay. The base of the

barrier sands lies at 2.0m to –2.0m. Two cores along the inner edge of the permatang showsinter-digitation of sediments, suggesting a permatang built up under stable sea level during

the formation of the younger permatang series. Based on morphological and stratigraphicevidence, the Holocene evolution of the Bachok coast is interpreted as consisting of thefollowing sequence. As the sea rose at the beginning of the Holocene marine transgressionabout 20,000 years ago, a barrier formed along the outer edge of the continental shelf startedmigrating shoreward to transgress a marsh or lagoon and came to rest on the coastal plaintrapping a lagoon behind it. None of this barrier has been preserved on the surface. When thesea started to recede an outer bar emerged as a barrier-lagoon system. During a period ofstillstand, there was upward accretion giving rise to inter-digitation along its inner margin.Following a new phase of sea recession or increased sediment sand supply, the permatang widened by the addition of beach ridges and spit formation. None of the older barrierdeposits stranded when the Holocene sea reached its maximum height has been preserved on

the surface along the Bachok sector.

KN 6: Lithostratigraphic section of Bachok

BACHOK DOUBLE PERMATANG COAST

This coastal sector from Terengganu border to Bachok is similar to the Kuala Besut sector ofTerengganu and in effect is an extension of it. The coast is characterized by a well-developed and preserved double permatang series, which occupies nearly the whole coastal

plain (KN 7). The coastal plain is about 12 km wide, with rock outcrops at Gunong Panchorand Bukit Peraksi. The coastal alluvium is relatively shallow, being less than 50m exceptnear the coast. Two permatang series are clearly recognizable; an older formation of broadridges, trending discordant to the coastline north of Sungai Semerak but concordant to the

coastline south of the river, where the ridges can be traced extending from the sedimentaryBukit Peteri hill, and a younger formation of closely-spaced narrow ridges. The two



formations are separated by a clay-filled depression. An abandoned levee system traversesthe younger ridges of the older series, but ends abruptly against the younger series, indicatinga pronounced time-break between the formations of the two series.

KN7: Coastal geomorphology of Bachok

Between the rivers of Kemasin and Semerak the inner barrier shows two phases of formation,Jelawat phase and Gunong Panchor phase. Each formation is about 3km wide and composedof about a dozen ridges cresting at less then 5.0m. The ridges fade away southwards,

probably reflecting the southward littoral drift during their formation. The Gunong Panchor phase appears to be associated with an old river mouth draining into the sea south of GunongPanchor, as the ridges on either side of the ‘mouth’ flare towards it. This old river is stillrecognizable on aerial photographs and can be traced to Kampung Melor. The oldest ridgehas been dissected in several places by a meadering tributary of Sungai Semerak. The sandsare fine grained, moderately sorted and positively skewed and the soils unpodzolized.Ilmenite and zircon co-dominate the heavy mineral fraction.

The ridges of the Jelawat phase are better preserved. The most landward ridge runs for about20km and appears to have slightly truncated the small delta apex associated with the ridges



of the Gunong Panchor phase. At the northern end, the older ridges flare seawards whereasthe younger ridges are linear. The youngest ridge converges southwards towards the outer

barrier and meets it at an angle of about 23 degrees. The sands have a coarse fraction,medium grained and poorly sorted.

The inner margin of the outer barrier stands up abruptly from the inter-barrier depression(KN 8). The northern portion is a swampy sand plain, showing a few poorly defined beachridges, but towards the south are more than 100 well-defined ridges, cresting at 2.7-4.5m,with the older ridges usually higher than the younger ones. At the southern end, the inner

portion of the barrier is dissected by Sungai Semerak, which then flows southwards behindan old spit before discharging into the sea. Two large old channels about the same width asthe present river can be traced from Sungai Semerak just inland of the outer barrier to drainsouthwards along the outer portion of the inter-barrier lagoon. The present littoral drift at themouth of Sungai Semerak is northwestwards. There has been a reversal in littoral drift sincethe formation of the outer barrier. The sands are medium grained and moderately sorted andilmenite and zircon dominate the heavy mineral fraction, as in the inner barrier.

KN8: Inter-barrier infilled lagoon and inner edge of outer barrier

Erosion at Bisikan Bayu to the south of Sungai Semerak have resulted in the closure of theriver mouth in February 1990, caused by an estimated 150,000 cubic metres of erodedsediments transported northwestwards by the littoral drift. Fishing boats were unable to leavethe river mouth. The river mouth was dredged as a short-term measure. Since then the riverhas been shortened and a new outlet opened to the sea near Kampung Tok Bali (KN 9).



KN9: A new channel being dredged across the outer barrier to shorten Sungai Semerak

Gigantic breakwaters protect the new Semerak river mouth (KN10). Although there were plans to fill up the old channel and river mouth, recent field observation shows that this hasyet to be carried out. The design of the breakwater anticipated the southern side of the

breakwater to accrete and the northern to erode.

KN10: Breakwaters protecting the new Sungai Semerak river mouth from siltation.



ABANDONED CUSPATE DELTA

This coastal sector, from Bachok to Kuala Besar, forms the southern portion of the Kelantandelta. The protruding abandoned Pengkalan Datu delta dominates the coast (KN11). Sungai

Pengkalan Datu is an abandoned distributary of Sungai Kelantan and is located at the apex ofthe receding Kelantan cuspate delta. A submarine wedge extending from the apex representsremains of the old delta. The old delta front will continue to recede until a new equilibriumstatus is established. There have been several suggestions regarding the year of shift, from1879 to 1920 which are obviously too recent. This was recognized and revised to about 1700(Tillmans 1991), but the basis for the revision is not explained. Based on the truncation of the

beach ridges by the preset coastline, the old delta front was estimated to be about onekilometre seawards (DHL 1984).

KN 11: Coastal geomorphology of the abandoned cuspate delta

The outer barrier continues northwards from the Bachok coast, becoming broader towardsPengkalan Datu. However, the inner barrier, so well developed and preserved to the south, isabsent here. The absence of the inner barrier here is the result of meandering rivers that have

completely eroded away the old ridges. This destruction can be presently observed at thenorthern portion of this coast, where the northwestern margin of the outer barrier has beeneroded away by an old river meander (KN 12).



KN12: Geomorphology of northern cuspate delta

In the southern portion, the outer barrier is built up by different beach ridge series, one ofwhich show landward recurves elongating northwestwards and deflecting Sungai Kemasin in



the same direction (KN 13). Inland on the swampy plain are old levees. The surfacemorphology of this northern portion is interesting, with different phases of beach ridgeformation some parallel, others flaring towards the mouth of Pengkalan Datu, the largemeander scrolls and abandoned levees that snake across the coastal plain where the inner

barrier once stood. The more seawards ridges show an increasingly degree of truncation in a

northward direction by the present coastline, indicating the cutback of the old delta front.Inland, several levees end abruptly against the inner margin of the outer barrier, indicatingthat the levees predate the outer barrier.

KN13: Geomorphology of southern cuspate delta

The retreat of the old delta has resulted in very severe erosion especially after theconstruction of the breakwater at the mouth of Pengkalan Datu (KN14). The Pantai Sabakcoast along the western portion of the abandoned delta front started experiencing severeerosion in 1991, five years earlier than the year of 1996 predicted by DHL (1984).



KN14 Pangkalan Datu breakwater

The emplacement of breakwaters at the mouth of Sungai Pengkalan Datu in 1987exacerbated the erosion along the downdrift coast at Pantai Sabak . An unsuccessful attemptwas made to mitigate the erosion by beach nourishment, and the strip of land separating the

boat harbour from the sea was breached in 1989. Land, houses and public infrastructures andhistorical monuments were washed away (KN15). The erosion coincided with the highest

mean sea level recorded from 1987 to 1992 (Toyoshima 1994). The erosion was aggravated by a decrease of an estimated 200,000 cubic metres of sand. Over a period of four years from1983 to 1986 about 700,000 cubic metres of sands were dredged from the riverbed, 5-6kmupstream from the mouth. The emplacement of the breakwater also resulted in river mouths

bars being formed farther offshore and the sands being returned to the beach system beingdelayed.

KN15: Pillbox stranded in the sea at Panati sSabak



Field monitoring in mid 1992 recorded a maximum coastline advance of 140m updrift of the

breakwater and this increased to about 250m by April 1993 (Teh and Shamsul Bahrin 1995). The accretion gradually extended to about one kilometre upcoast (KN16). Severe erosionoccurred on the downdrift side and several villages had to be relocated . Initially, erosion was

most severe near the breakwater, but the eroding sector gradually extended downcoast toaffect all the villages located there. The worst erosions were experienced during the northeastmonsoon of 1990 when the beach retreated 30m and during 1992/1993 when the rate ofretreat over six months was 4.76 m per month (Teh and Shamsul Bahrin 1995).

KN16: Erosion map of Pantai Sabak

The beach was repaired, the coastline armoured and the breakwater redesigned to incorporatea spur. At Pantai Sabak, the villagers in about 530 households were affected by erosion(KN17) and had to be relocated to Kampung Gajah which ironically was also threatened byerosion a few years later (KN18). The Sabak coast continues to suffer from erosion and thereis yet another attempt in 2003 to address the problem. This has become urgent as the burialground of the abandoned villages is being eroded away. Previous measures considered tocombat the erosion included construction of groynes, beach nourishment, sand bypass or do

nothing.



KN17: Effects of erosion at Pantai Sabak

KN18: Relocated resettlement at Kampung Gajah threatened by erosion

Across Sungai Pengkalan Datu to Pengkalan Chepa, the surface morphology is dominated bya complex pattern of beach ridges, with fluvial activities eroding away many of the olderridges (KN19). An old meandering river system which can be traced to join up with SungaiPengkalan Datu have eroded away the older ridges but ends abruptly against the younger

beach ridges, recording the relative ages. The older ridges can also be traced across SungaiKelantan to the Tumpat coast. There is strong evidence that the ridges predate the presentSugai Kelantan. The progressive migration of Sungai Kelantan in a westerly direction would

explain the absence of the inner barrier along the Bachok coast and their presence on eitherside of it. This portion of the delta is prone to flooding being near to Sungai Kelantan. Sands



are regularly dredged from the river mouth and the first river groynes in Malaysia wereemplaced here.

KN19: Coastal geomorphology of the Pengkalan Chepa coast

The wide beach of coarse reddish sands at Pantai Cahaya Bulan (PCB) is the most popular beach along this coast (KN20). The beach shows drastic changes in morphology, beingseverely eroded during the northeast monsoon and recovering rapidly during the southwestmonsoon. The seasonal erosion has become more severe as the erosion downdrift ofPengkalan Datu breakwater extends towards Pantai Cahaya Bulan and threatens thenumerous resorts. A dewatering project was carried out in an attempt to restore the beach

but there are no reports on whether this had been successful.

KN20: The popular beach of Pantai Cahaya Bulan is monsoon influenced, eroding severelyduring the northeast monsoon but recovering in the following calm monsoon



TUMPAT LAGOON

This coastal sector, from Kuala Besar to Sungai Golok, is the modern Kelantan delta,composed of mangrove deltaic mangrove islands and the Tumpat barrier spit (KN 21). Inland

are cheniers resting on deltaic mud and two series of beach ridges, the older formationending before Sungai Kelantan but the younger formation extending across the river intoPengkalan Chepa. Along the landward edge of the older series, the sedimentary sequenceconsists of barrier sands, lagoon/marsh deposits and Pleistocene mottled clay. The barriersands show a basal coarse facies and the base lies at about mean sea level. On the youngerseries, the sequence shows barrier sands and lagoon/delta sands over a coastal wedge ofreverse graded sand, silt and clay bed, resting on a Pleistocene surface. The base of the

barrier sands lie at 0-2m below mean sea level.

KN21: Coastal geomorphology of Tumpat coast

The rapid evolution of this spit has been studied over the years. The Tumpat spit was firstrepresented on the 1880 map, but it had an earlier origin as by then the spit was well

developed. When first mapped the spit was attached to the right bank of Kuala Besar, butsome time between 1880 and 1939, its base was breached and the spit migrated shorewardsto become attached to the left bank of Kuala Besar Smaller spits have continued to growfrom the right bank, but these often break up into crescentic sand islands. Koopmans (1972)traced the evolution of the spit from 1944 to 1966 and showed its westward elongation byabout 2.5 km and shoreward migration by at about 1.0km. Raj (1985) traced the evolutionfrom 1939 to 1974 and showed the spit migrating shoreward and elongating towards PantaiSri Tujuh but have yet to link up with the mainland. The link-up took place at Pantai SriTujuh in 1977 and the lagoon was completely enclosed temporarily. Sands arriving at SriTujuh accreted to form a wide sand terrace (KN 22). After attaching itself to the mainland,the spit continued to change in shape and position (KN23). Attempts to develop the spit for

local tourism failed because of the highly dynamic nature of the spit. What happened in Sri



Tujuh is often used as an example of the folly of coastal development on sensitive areaswithout understanding or failing to take into consideration coastal processes.

KN22: Accretion at Pantai Sri Tujuh to form a wide sand terrace used for the internationalkite festival when the spit attached itself to the mainland

KN23: Evolution of Tumpat Spit 1949-1990



The breach in the Tumpat spit was maintained by dredging (DHL 1984). The spit waseroding on the seaward side and during storms the sands were washed over the spit anddeposited inside the lagoon (KN 24). Within the lagoon is a strong counter current,elongating two small spits eastwards. The Kelaboran spit is the first site of the Japaneselanding in Malaysia during the Second World War.

At Sungai Golok a long narrow spit extended westwards and the changing river mouthmorphology posed problems in determining the international boundary between Malaysiaand Thailand. A breakwater was constructed at the river mouth on the Malaysia side toaddress the problem. It also meant that sands were not transported by littoral drift across the

border.

KN24: Shoreward migration of Tumpat spit by process of sands being washed over the spitand depositing in the lagoon during storms.

References

Chu, L. H. 1975. A brief report on the investigation of the beach sand deposits of Kelantan.Annual report, Malaysia Geological Survey. Ipoh

Delft Hydraulics Laboratory (DHL) 1984. Kelantan Minor Port Project . Kuala Lumpur.

Economic Planning Unit 1985. National Coastal Erosion Study. Kuala Lumpur.

Economic Planning Unit 1986. National Coastal Erosion Study, Phase II. Feasibility StudiesKuala Lumpur.

ENEX 1977. The Kelantan Basin Study.

Koopmans B.N. 1972. Sedimentation in the Kelantan delta (Malaysia). Sedimentary Geology7: 65-84.



Raj, J.K. 1982. Net directions and rates of present-day beach sediment transport by littoraldrift along the east coast of Peninsular Malaysia. Bulletin Geological Society Malaysia 15:57-70,

Raj, J.K. 1985. Recent and near-future coastal changes of Kelantan state, Peninsular

Malaysia. ITC Publications: 1985-1,

Shamsul Bahrin, Tengku and Teh T. S. 1994. Socio-economic impacts of erosion at PantaiSabak, Kelantan. Malaysian Journal of Tropical Geography 25: (2): 129-142.

Swan B. St. C. 1968. Coastal classification with reference to the east coast of Malaya. Zeitschrift fur Geomorfologie, Suppl. Bd. 7: 114-132.

Teh T. S. and Shamsul Bahrin, Tengku 1995. Failure of the Pengkalan Datu Breakwater inKelantan: Some lessons learned. Malaysian Journal of Tropical Geography 26: (2): 159-167.

Toyoshima, S. 1994. Tidal phenomena and sea level variations around Peninsular Malaysia.Paper presented in Seminar on Tides and Tidal Phenomena, Kuala Lumpur.

Zakaria Awang Soh 1972. Sediments of Kelantan delta: grain-size distribution in differentenvironmental conditions. NUSANTARA 2: 169-187.

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THE WORLD’S COASTS: KELANTAN, MALAYSIA