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The World's Coasts: ONLINE
19 South East Asia
19.2 MALAYSIA
19.2.11 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 of
Peninsular 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 Thailand
along Sungai Golok. The Kelantan coast, which is wholly sandy, forms the outer edge of the
Kelantan 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 South
China Sea, has a concave sector at Sungai Semerak, a protrusion at Pengkalan Datu and an
irregular 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 a
30km wide alluvial plain whose surface is often interrupted by abandoned levees and
meander 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. A
15m deep unbottomed borehole near the beach records an upper layer of sand, succeeded
downwards by sandy clay and clay. The sands were iron stained and unsuitable for glass
making. The common heavy minerals were ilmenite, amphibole, tourmaline, magnetite,
zircon and rutile. Pyrite and foraminefera, commonly pyritised, increases with increasing
depth (Chu 1975).
KN1 Background map of Kelantan
Over 70% of the coastline is in retreat (EPU 1985). Severe erosion is taking place along the
old delta front at Pengkalan Datu and a westward elongating spit extending from the present
Sungai 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 that
retreat 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 all
the major rivers or at newly created river mouths. The opening of river mouths is part of the
flood mitigation programmes and also to facilitate the movement of fishing boats, and in
some 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 river
mouths 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 high
and often there is one low water in a day (Toyoshima 1994). The maximum tidal range is
1.2m and the mean spring tidal range of 0.6m is the lowest recorded in Malaysia
(Hydrographic Directorate, Royal Malaysian Navy 2003). During the northeast monsoon
there 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 sediment
yield 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 siltclay 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 net
longshore 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 Cahaya
Bulan-Kuala Besar coast (EPU 1986). The figures given for the various sectors suggest that
29,000 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 is
located between Sungai Besar and Sungai Kemasin and the second between Kampung
Cerang Ruku and Sungai Semerak. Coasts facing north would have a northwestward littoral
drift and east facing coasts would have a southeastward littoral drift (DHL 1984). The
convergent 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 spit
and 55m per year for Sungai Kemasin, and the southeastward spit elongation for Sungai
Semerak is 30m per year (Raj 1982). However, like all east state coasts there is a strong
seasonal nature of wave approach and hence different drift directions and rates of sediment
transport 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 and
marine deposits along its outer margin (KN 4). The depth of the alluvium exceeds 100m in
the inner portion of the coastal plain and the deposits form an important source of ground
water 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 Gunong
Panchor. Permatang deposits with intervening infilled lagoons dominate the southern sector.
The older series are composed of broad ridges separated by elongate depressions occupied by
fresh water swamps and the younger series is a continuous belt composed of closely spacing
ridges. Meandering rivers occupying the depressions have reshaped the inner margin of each
older permatang series. The orientation of the older series does not run parallel to the present
coastline 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 exception
is 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 rate
of 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 an
abandoned 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. Various
dates have been proposed, but there is little scientific basis for the dates advanced. Study of
old small-scale maps has not helped either; as such maps are not very reliable. More detailed
information 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 westerly
migration of the Sungai Kelantan (KN5).
KN5: Evolution of the Kelantan delta
The lithostratigraphic section in Bachok, constructed from six cores, shows that behind the
younger 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/marsh
organic 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 shows
inter-digitation of sediments, suggesting a permatang built up under stable sea level during
the formation of the younger permatang series. Based on morphological and stratigraphic
evidence, the Holocene evolution of the Bachok coast is interpreted as consisting of the
following sequence. As the sea rose at the beginning of the Holocene marine transgression
about 20,000 years ago, a barrier formed along the outer edge of the continental shelf started
migrating shoreward to transgress a marsh or lagoon and came to rest on the coastal plain
trapping a lagoon behind it. None of this barrier has been preserved on the surface. When the
sea started to recede an outer bar emerged as a barrier-lagoon system. During a period of
stillstand, 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 barrier
deposits 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 of
Terengganu and in effect is an extension of it. The coast is characterized by a welldeveloped 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 Panchor
and Bukit Peraksi. The coastal alluvium is relatively shallow, being less than 50m except
near the coast. Two permatang series are clearly recognizable; an older formation of broad
ridges, 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 sedimentary
Bukit 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 traverses
the younger ridges of the older series, but ends abruptly against the younger series, indicating
a 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 composed
of 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 Gunong
Panchor, as the ridges on either side of the ‘mouth’ flare towards it. This old river is still
recognizable on aerial photographs and can be traced to Kampung Melor. The oldest ridge
has been dissected in several places by a meadering tributary of Sungai Semerak. The sands
are 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 about
20km 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 whereas
the 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 beach
ridges, 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 behind
an old spit before discharging into the sea. Two large old channels about the same width as
the present river can be traced from Sungai Semerak just inland of the outer barrier to drain
southwards along the outer portion of the inter-barrier lagoon. The present littoral drift at the
mouth of Sungai Semerak is northwestwards. There has been a reversal in littoral drift since
the formation of the outer barrier. The sands are medium grained and moderately sorted and
ilmenite 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 the
river mouth in February 1990, caused by an estimated 150,000 cubic metres of eroded
sediments transported northwestwards by the littoral drift. Fishing boats were unable to leave
the river mouth. The river mouth was dredged as a short-term measure. Since then the river
has 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 has
yet 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 Kelantan
delta. 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 of
the receding Kelantan cuspate delta. A submarine wedge extending from the apex represents
remains of the old delta. The old delta front will continue to recede until a new equilibrium
status is established. There have been several suggestions regarding the year of shift, from
1879 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 one
kilometre seawards (DHL 1984).
KN 11: Coastal geomorphology of the abandoned cuspate delta
The outer barrier continues northwards from the Bachok coast, becoming broader towards
Pengkalan Datu. However, the inner barrier, so well developed and preserved to the south, is
absent 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 the
northern portion of this coast, where the northwestern margin of the outer barrier has been
eroded 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 of
which show landward recurves elongating northwestwards and deflecting Sungai Kemasin in
the same direction (KN 13). Inland on the swampy plain are old levees. The surface
morphology of this northern portion is interesting, with different phases of beach ridge
formation some parallel, others flaring towards the mouth of Pengkalan Datu, the large
meander 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, indicating
that 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 the
construction of the breakwater at the mouth of Pengkalan Datu (KN14). The Pantai Sabak
coast along the western portion of the abandoned delta front started experiencing severe
erosion 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 1987
exacerbated the erosion along the downdrift coast at Pantai Sabak. An unsuccessful attempt
was 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 and
historical 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 from
1983 to 1986 about 700,000 cubic metres of sands were dredged from the riverbed, 5-6km
upstream 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 being
delayed.
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 erosion
occurred 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 to
affect all the villages located there. The worst erosions were experienced during the northeast
monsoon of 1990 when the beach retreated 30m and during 1992/1993 when the rate of
retreat 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 incorporate
a 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 by
erosion a few years later (KN18). The Sabak coast continues to suffer from erosion and there
is yet another attempt in 2003 to address the problem. This has become urgent as the burial
ground of the abandoned villages is being eroded away. Previous measures considered to
combat 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 by
a complex pattern of beach ridges, with fluvial activities eroding away many of the older
ridges (KN19). An old meandering river system which can be traced to join up with Sungai
Pengkalan 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 Sungai
Kelantan to the Tumpat coast. There is strong evidence that the ridges predate the present
Sugai 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 either
side 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 were
emplaced 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, being
severely eroded during the northeast monsoon and recovering rapidly during the southwest
monsoon. The seasonal erosion has become more severe as the erosion downdrift of
Pengkalan Datu breakwater extends towards Pantai Cahaya Bulan and threatens the
numerous 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 severely
during 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 formation
ending before Sungai Kelantan but the younger formation extending across the river into
Pengkalan Chepa. Along the landward edge of the older series, the sedimentary sequence
consists of barrier sands, lagoon/marsh deposits and Pleistocene mottled clay. The barrier
sands show a basal coarse facies and the base lies at about mean sea level. On the younger
series, the sequence shows barrier sands and lagoon/delta sands over a coastal wedge of
reverse 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 first
represented 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, but
some time between 1880 and 1939, its base was breached and the spit migrated shorewards
to become attached to the left bank of Kuala Besar Smaller spits have continued to grow
from 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 by
about 2.5 km and shoreward migration by at about 1.0km. Raj (1985) traced the evolution
from 1939 to 1974 and showed the spit migrating shoreward and elongating towards Pantai
Sri Tujuh but have yet to link up with the mainland. The link-up took place at Pantai Sri
Tujuh in 1977 and the lagoon was completely enclosed temporarily. Sands arriving at Sri
Tujuh 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 areas
without understanding or failing to take into consideration coastal processes.
KN22: Accretion at Pantai Sri Tujuh to form a wide sand terrace used for the international
kite 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 was
eroding on the seaward side and during storms the sands were washed over the spit and
deposited 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 Japanese
landing in Malaysia during the Second World War.
At Sungai Golok a long narrow spit extended westwards and the changing river mouth
morphology posed problems in determining the international boundary between Malaysia
and Thailand. A breakwater was constructed at the river mouth on the Malaysia side to
address 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 spit
and 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 Studies
Kuala Lumpur.
ENEX 1977. The Kelantan Basin Study.
Koopmans B.N. 1972. Sedimentation in the Kelantan delta (Malaysia). Sedimentary Geology
7: 65-84.
Raj, J.K. 1982. Net directions and rates of present-day beach sediment transport by littoral
drift 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 Pantai
Sabak, 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 in
Kelantan: Some lessons learned. Malaysian Journal of Tropical Geography 26: (2): 159167.
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 different
environmental conditions. NUSANTARA 2: 169-187.