1 Introduction

1.1 Aims and Objectives

This report aims to provide an evaluation on the coastal processes response and its management on Miri coast. The goals of the study are listed as below:

1. To evaluate the coastal landforms, 2. To identify natural and human-related processes to the coast, 3. To identify current and potential future threats to coastal environment4. To identify key issues for sustainable management of the coast.

1.2 Methodology

1.2.1 Aerial view and preliminary survey The coastal region was surveyed thoroughly with the aid of an aerial map obtained from Google Earth. Hence, accessible site and potential hazards were identified prior visits. In addition, the tide schedule was used to identify the best date and time for the coast visits.

1.2.2 Beach profile measurement and field observation

By using Emery rod method, the beach profiles for two beaches were measured. The profile measurement was done at the lowest tide level possible to get better data. Besides, intense observations throughout the coastal region were done and studied.

2 Locality Description

The coastal region covered is between Kuala Baram and Luak bay of the coast. There are three localities that have been chosen for this study. All of the sites visited are described as below:

2.1 Geology and background

2.1.1 Tanjung Lobang It is a famous tourism spot where it has clean sandy beach. The unconsolidated sand has well sorted fine grained size. It is believed to form during middle Miocene age of Miri Formation.

2.1.2 Luak BeachIt consists of sedimentary rocks from Tukau formation which is relatively younger than Tangjung Lobang. The sediment has coarser than sands found at Tangjung Lobang too.

2.1.3 Kuala BaramThis locality is believed to be from upper Miocene age. It has a sequence of sedimentary rocks. The sediments here are also coarser in size and poorly sorted compared to the other localities.

2.2 Topology and Geomorphology

The topography of all beaches near the coastline and the few hundred meters landward is relatively low. All beaches are separated with erosion defence structures which are about 1.5m relief height in average. However, different localities still have unique landforms and that differentiate them from the other sites.

2.2.1 Tanjung Lobang

It has approximately 600 meters long beach. The relief is significantly changing landward due the presence of past tectonic activities at the area that resulted in an upliftment of Miri Hill. In the southwest direction, there is a rock cliff exposure of 30 meters height which was once a part of Miri Hill before it eroded away. The evidence of this beach formation is shown by the different vegetation types that exist at the beach and the cliff (fig. 1).

2.2.2 Luak BeachThe beach is stretching seaward with very gentle inclination. The beach faces the ocean openly and has relatively straight coast line.

Figure 1: The view to the southwest direction of the beach where two different types of vegetation (labeled as A and B) are observed. A is at the beach side whereas B is located on the cliff side.

2.2.3 Kuala Baram Beach It has a straight coastline with limited beach width. However, as closer proximity toward the Baram river mouth. Significant chances are seen as depositional features such sand dunes were observed. Occasionally, these sand dunes are believed to be flooded with seawater. At the middle segment of Kuala Baram, several sand bars presence thus creating a small lagoon which separates the bars from the coast. Delta formed at the river mouth as high deposition of sediments present.

2.2.4 Beach profile assessment Beach profile was done at two of beaches, which are Tanjung Lobang and Luak beach. The profile would aid in term of evaluating the landform better and the processes that have mannered them. The profiles of the beach are shown below:

Characteristic Tanjung Lobang beach Luak beach

Average slope 1.10˚ 0.45˚.

Profile features Accretion bump and through

Straight dipping with no bump

Dunes Artificial dunes are much larger

Smaller artificial dunes

Table 1: Comparison of both beach where profiling was done.

Figure 2: Shown small lagoon separated by sand dune at Kuala Baram

beach. The sand dune is very low in elevation and sparsely vegetated.

2.3 Drainage (Hydrology)

2.3.1 Tanjung Lobang

Two little streams are observed here. One of it is an active drainage system where the surface runoff from the surrounding is channelled into this man-made stream. Flow rate of the stream was measured during the visit and displayed below (fig. 3). Another stream is a stagnant stream originated from the native vegetation area. Furthermore, many logs are scattered in and around the stream blocking the water flow.

Figure 3: Flow rate measurement of a man-made stream in Tanjung Lobang.

2.3.2 Luak BeachA small meandering river flow into the sea with higher volume compared to the one in Tanjung Lobang. Flow rate measurement at time of visit measured during the low tide period is in (Fig 4). The river deposited small mud flat area near the entrance to the sea. The mud flat is believed to be submerged during the high tide.

Figure 4: Flow rate measurement of a meandering river at Luak beach.

2.3.3 Kuala Baram beachBatang Baram river is located here. It supplies enormous sediment discharge from upstream to the sea. Besides, small streams which do not flowing during fair weathered days are present along the road that runs alongside the beach create swampy area. These streams only flow during rainy days. Compared to Tanjung Lobang, there is no proper drainage structure in this area.

2.4 Identified vegetation

The presence of vegetation provides important traction as they keep the sediments intact by spreading roots in earth. They are important as they are a part of natural protective mechanism of the coast. For example, vegetation covering the dune could lessen the wind energy, thus reducing erosion.

Figure 5: Swampy area at Kuala Baram.

5 m0.453 m m

The vegetation observed along the studied locality is shown in figure 5. Meanwhile, the presence and occurrence of these vegetations in the locality are summarized in table 2 below.

Figure 6: Collection of major vegetations found along the coast zone. A: Beach morning glory (Ipomaea pes caprae) B: Coconut tree (Cocos nucifera). C(i)(ii): Beach Rhu (Casuarina litorea). D(i): Mangrove tree at the rivermouth. D(ii) Baby mangrove at the swamp near the coastal roadside. E) Grass (Poaceae). F) Tall grass (typha angustifolia). G(i)(ii): Scaevola Plumieri. H) Agricultural plant at small scale behind warehouse worker house at Kuala Baram.

Vegetation type Tanjung Lobang beach

Luak Beach Kuala Baram beach

Remarks

A) Beach Morning Glory (Ipomaea pes caprae)

Stabilize sands and helps prevent sand erosion. Salt tolerance plant

B) Coconut tree (Cocos nucifera)

Indicate high salinity water

C) Beach Rhu (Casuarina litorea)

Serve as ditch and canal stabilization, shade and also as windbreaker.

D) Mangrove tree

Protect coastal areas from erosion, storm surge and tsunamis.Good for ecosystem.

E) Grass (Poaceae)

Ground cover and dune stabilization.

F) Lalang (typha angustifolia)

Common in marshy area

G) Scaevola Plumieri

Ground cover and dune stabilization.

H) Agricultural plant

Banana, corn and vegetables.

Legends

Growth naturally

Believed to be planted

*The number of stars indicates distribution of the vegetation.

One star = Sparsely vegetation Two stars = Moderate in amount There stars = Plentiful

Both natural and planted

Not seen

Table 2: The summary of vegetation presence at the three beaches and their relatively distribution.

2.5 Human activities

For centuries, the coastal region has been beneficial for human beings. However, due to human interruption of the natural ecosystem equilibrium, there are always consequences no matter good or bad to the region. Activities could take place offshore or inland regardless of the scale. Below, the impact of each activities and community mostly affected are discussed.

Activity Impact Communities affected2.5.1 Recreational & Tourism

Clean beach that qualified and strategic to become an attraction for locals and tourists alike.

Positive- Promote healthy economy- More development as infrastructures needed to attract visitors. - Strengthening of coastal defence to protect the coast.

Negative- Beach rendered to dirty.- Destruction of vegetation and marine life habitat.

- People living by the coastal zone. -Tourism personnels. - Coastal ecosystem.

2.5.2 Fishing industry

Many fishermen conduct fishing activities at Kuala Baram.

Positive- Source of income and protein for people.

Negative- Uncontrolled fishing could render some fish species to extinction. - Marine structures obstruct the sediment drift

- Fishermen- Consumers- Marine life

2.5.3 Urbanization & development

Development of coastal residences and Marina bay (reclaimed land) could bring more harm than good, especially to the ecosystem.

Planned development of dam at upstream of Baram river could also be harmful.

Positive- Developing better city for living.- Create new attraction and residences.

Negative- Reclaimed land proves destructive to the local river system and mangrove forest.- Land clearance. - Destruction of surrounding fauna.

- Coastal ecosystem- Human population

2.5.4 Offshore rigs, Shipping and Warehouse.

Operating oil rigs could be seen from the coast. Tankers and shipping for the trading.

Positive- Growing oil and gas industry.-Improve country economy.

Negative- Possible source of pollution for example oil spills in ocean. - Degrade water quality.

- Oil and gas community. - Marine ecosystem

2.5.5 Industrial activites

Industrial activity along the coastal area and river system such as logging, furniture and cement factory.

Spotted at Kuala Baram offshore. The exact location of the dredging is unknown. It is believed that the sand is used either for reclamation purpose or mould to be concrete.

Positive- Good for economic and industrial growth. - Job opportunities for rural area people.

Negative- Destruction of natural habitat. - Destruction of Penan villages and source of living

- Interior community living upstream. - Coastal ecosystem

Table 3: Summary of human activities happening along the coastal zone together with their impact and communities that could be affected.

Figure 7: Some pictures demonstrate the human activities currently happening along Miri Coast. A: Land clearance by burning the vegetation area. B: Sea and river sediment dredging

for beach nourishment and land reclamation. C: Large ship boarding at the port at Kuala Baram. D: Ship that fully loaded with logs. E: Boat construction activities for fishing and

recreational. E: Ship rope that stranded at the rip rap at Kuala Baram beach. G: Offshore rigs and shipping activities observed from coast. H: Warehouse to keep the ship trade commodity.

I: A cement making factory at Kuala Baram.

Logs

2.6 Man-made structures and impact 2.6.1 Human development, residential facilities

Most of the features have been built as a comfort for better living. The features are as listed below:

o Bridge

o Children playground

o Factories

o Fish market

o Housing / Residences

o Schools

o Man made drainage

o Recreational facilities

o Roads

Along the coastal zone that had been studied, the trend/density of development can be directly correlated to the density of human population. More buildings or development projects are signs of a highly populated area. As example, along the shore from Lutong developments are low in density. Whereas, further upward to Baram river the development gets moderately denser.

2.6.2 Erosion Defense and Beach Stabilization structure

These structures could be further typecast into hard defenses and soft defenses. Hard defenses are man-made rigid structures generally constructed with concrete and steel. Whereas, defenses that are made of unconsolidated material such as sand are known as soft defenses. Both are used as a coastal defense against erosion and flooding.

2.6.2.1 Rocks (Rip Rap) and wood revetments

Located along the coast, it separates the sandy beach from the vegetation line. The rocks used are mostly limestone. However, at Tanjung Lobang, granite is more commonly used. These rock are not common in Miri region, thus had to be imported. They are designed so that the waves lose their energy breaking on the structure instead on the beach. Further erosion could be prevented by dispersing the tide energy. At Kuala Baram this rock revetment is covered by geotextiles believed to improve effectiveness.

Furthermore, at Kuala Baram the rock revetments were not just aligned parallel to the coast but also purposely aligned perpendicular to the coast (fig. 4). It is believed this has been done to replicate the same working principle of a groyne but at a smaller scale.

At Tanjung Lobang, there are logs that are vertically positioned half buried. This is believed to obstruct the logs from entering the sea or scattering around beach.

Figure 8: Rock revetment (rip-rap) along the coastline. A: View from one side of Kuala Baram beach. B; Geotextile that cover the rocks.

Figure 9: Aligned rock revetment perpendicular to the coast. The white arrows indicate the orientation direction of the rocks. Aii)Close-up view of the rock revetment from the coast to seaward.

2.6.2.2 GabionMainly found at Tanjung Lobang, hard rocks are wrapped in heavily galvanized wire cage and then stacked on one another to stabilize the slope against erosion and prevent cliff falls.

2.6.2.3 Groyne (Wave breaker) Two groynes 100 m in length each are built at Tanjung Lobang. They are straight, narrow in width and perpendicular to the shoreline. Huge amount of foreign rock (granite) were brought over with approximate volume 7000m3. They are meant to stabilize the coast where they control the sediment movement along the coast.

2.6.2.4 Sand bag This soft coastal defense is sand that is covered by geotextile piled on top of one another and placed against the slope. As it does not involve any concrete or hard structures, these sand bags replicate the protective characteristics of natural beach and dune systems.

Besides that, there are signs of sediment replenishment activities observed at Tanjung Lobang. It is almost unnoticeable at first as the foreign sand is relatively similar with the existing sand. However, the remnant of sacks on the beach floor could be evidence of sand replenishment activities. This is to ensure that the foreign sand can integrate with the natural processes and thus enhance the beach.

Figure 10: Logs that are vertically positioned half buried along the stream at Tanjung Lobang.

2.6.1 Marine structureThe structures are mainly developed for fishing, tourism, and shipping. Small jetties are observed along the coast as they are used as inlets for boat entry. Marina bay particularly, has wharfs to keep the recreational boats. The port is established for trade cargo and ships in northern region of Sarawak. Also, huge warehouses were built for strorage also took up large of land space.

Figure 11: Erosion defense and beach stabilization structure observed along the studied coast. A: Gabions are placed along the highly erosive part adjacent to the sea food restaurant. B: Groynes at Tanjung Lobang.

C: Sand bags are piled on top of another against the slope. D: Concrete revetment fixed against the slope.

3 Coastal Processes interpretation

The coastal environment is one of the most dynamic and dramatic in terms of changes in its physical environment. Thus, humans who are highly dependent on the coast should have a deep understanding regarding this matter. In particular, its natural processes – tides, waves, winds, and currents are constantly reworking the coastal zone. It is also easily influenced by anthropogenic activities. Therefore, understanding of coastal zone influences whether natural or manmade is important.

3.1 Miri tidal characteristics and analysis

3.1.1 Data

From the monthly tide schedule, a sinusoidal graph for August is illustrated and graph of each tidal phase is deduced.

3.1.2 Graph

Figure 8: Miri Tidal Schedule, August 2010.

Last Quarter

New Moon

First Quarter

Full Moon

DiurnalSemidiurnal SemidiurnalDiurnal

Figure 12: Plot for main tidal phases.

3.1.3 Tidal Characteristics

Phase Type Range, cm Low and lower low,

cm

High and higher high,

cmLast quarter

(neap)Diurnal 35 69 104

New moon (spring)

Diurnal 190 10 180

First quarter (neap)

Diurnal 102 47 149

Full moon Semidiurnal 101 46, 91 99, 147Overall Mixed 179 1 180

Table 4: Main tidal phase data.

Based on the graphs, Miri has mixed tides which are mostly diurnal. The tidal range is 179 cm (microtidal). The tidal waves have moderate energy with parallel direction to coastline except in embayment and river mouth. The direction is angled that it can be observed from the ripple mark orientation along the beach.

3.1.4 Interpretation

Diurnal phase occurs due to the moon day not being equal to the solar day although in most places, the moon finishes its cycle more than once in a solar day (called semidiurnal). The large range of tide is due to a number of factors. Miri is located close to the equator where the pull of the moon is the strongest during spring. The range changes in response to the position of the sun and moon relative to Miri’s location. The coastal shape also influences the tidal range. Miri’s coast faces the South China Sea, where the size of the basin is considered large with varying water depths; and straight long shorelines with wide continental shelves give larger tidal range. The range slightly decreases where there are river mouths and embayment as the tide is affected by water depth and river flow rate.

To discuss on regional context, Tawau (Sabah) tidal schedule is analyzed. Although Tawau is located around the same latitude as Miri, the relative position of moon and sun is the same. However, the range is bigger of 3.11 cm (mesotidal) compared to Miri tidal range. Tawau is indeed one of the six sites in Malaysia with highest tidal range as it faces an open and even wider Celebes Sea and the narrow strait between Tawau and Pulau Sebetik increase tidal wave energy.

Figure 13: Comparison of Tawau and Miri main tidal phases

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3.2 Coast classification Shepard coastal classification revised in 1973 is used for the coast classification. The classification is simply illustrated in the flow chart below attached together with their evidences.

Shepard coastal classification scheme (1973)

Primary coast Formed mostly by non-marine agent such by subaerial

deposition.

Secondary coast Shaped primarily by

marine agent or organism. Can be either primary coast or not

before being shaped by marine forces.

Erosion prone coast as deposition is less compared by

erosion.

Erosive features such sea cliffs and sea caves are seen especially at

Tanjung Lobang where bed rock is exposed.

Location: At Kuala Baram area which surrounds the river mouth.

Evidence: Enormous river discharge from Batang Baram river to form a river-dominated. Sand bar and lagoon observed.

Location: From Luak beach futher up to Kuala baram beach

Wave dominated erosion coast

Wave straightened coast.

Miri coast has small tidal range (microtidal <2m). Means more energy come from the waves.

Coast line is straightened by wave action as the coast line is relatively straight with no embayment at all.

Fu

rther classification

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3.2.1 Erosion process

3.3 Impact of Anthropogenic activities to Coastal Processes

Placement of jetties along the coast will alter the pattern of longshore sediment transport. It is the movement of sediment over long distances in a direction parallel to the shoreline. This causes interference to sediments natural flow as natural supply of sediment to feed the beach is decreased and river of sand becomes starved. Eventually results in narrower beach. Example, in Kuala Baram.

Groynes at Tanjung Lobang, for instance will trap sediment updrift of the structure and leaving less sediment to transport downdrift area, and creating more erosion.

This phenomenon can be seen along the Tanjung Lobang beach large volumes of sand deposited higher up of the beach, thus believed to be overwash sediments. The spot is deduced to be the updrift side based on the lithoral drive direction. It occurs as storm water exceeds the adjacent land due to very low elevation, absence of dunes and sparse vegetation covers.

Conversely, downdrift is believed to have happened on the north east side. Severe erosion occurred even where sediment was nicely covered by vegetation root (fig 11). The water could reach very high landward possibly due to combination of spring tide and heavy monsoonal rain especially during November to February which is usually accompanied by severe sea storms.

Over wash sediments

Figure 10: Over wash sediment that deposited as fan shaped features at south-west side of the beach.

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Rivers supply sediment to the coast and human activities, such as damming for hydroelectric power, can restrict the flow of sediment to the coast. Eventually, will cause sediment starvation along the coast and aggravate erosion.

4 Sustainable coastal management and threat

Sustainable coast l management

Figure 11: Severely eroded area as the vegetation root couldn’t stand the erosion that removed a lot sediments.

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nourishment can be used alongside the groyne schemes.

2.6 NATURE THREAT

Although coastal region is part of Mother Nature, it still can face some threats from it. Natural cycle can cause some damage to the coastal region.

Tide Change

Threats from Mother Nature can be as simple as tide changes to tsunami. Tide changes cause erosion and, if not controlled properly, the erosion might get severe. Erosion can speed up due to global warming effect and that is why basic defence like rip raps and gabbions are built along coastline.

RIP Current

Sometime, RIP current occurs at the Tg. Lobang beach. This sometimes caused by the groin built. RIP current has been proven fatal to human and can cause lost of lives.

Tsunami

As a whole, Miri coastline is still part of Borneo Island’s coastal region. Hyperbolic as it may sound, Borneo as an island is still prone to mega threat such as Tsunami due to its location. Any quakes at the trench line that can cause Tsunami surely can reach Borneo Island. If a Tsunami ever going to reach the coast, Miri can go down just like Aceh.

Current Condition

Coastal region of Miri current condition can be described as acceptable at some of the beaches we observed like Luak Bay and Tg. Lobang. Kuala Baram in the other hand can be described as in critical need of facelift and coastal management.

Luak Bay and Tg. Lobang might be in an acceptable condition due to its tourism and recreational importance. They are equipped with new and improved coastal defence measures compared to Lutong beach and Kuala Baram.

Kuala Baram in contrast, has been the victim of industrial activities. The condition of the beach including the coastal region can be described as not suitable for neither tourism nor recreation purposes. The defence measure seems old and just enough to prevent severe erosion on the beach.

Future Threat

Future threat might be plentiful and more dangerous if proper management of the coastal zone is not done.

Proposal of damn around Baram area also have been submitted to the government (http://www.utusan.com.my/utusan/info.asp?y=2010&dt=0218&pub=Utusan_Malaysia&sec=Sabah_

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%26_Sarawak&pg=wb_05.htm). This can cause sediment starvation to the beach area as its trapped at the dam. Development of residential area at along the coastline like in Lutong might seem beautiful but it also can possess danger to its community if suddenly big waves like tsunami ever happen.

Future Management

So, the government must start thinking long-term measure and planning instead of ignoring all these threats. Development must be parallel to nature conservation.

Recreational and tourism activity at the beach must be constantly monitored especially in term of the cleanliness of the beach. Strengthening of coastal defence also must be equal albeit the importance of the beach to tourism or not.

Industrial activity must be controlled and critical areas like mangrove forest must be strictly preserved from industrial activities. Strict control on the effluent that released to the open water also must be implemented.

People safety

Future development

Sustainability entails a continuous process of decision making, so there is never an end-state just a readjustment of the equilibrium between development and the protection of the environment[

Managing the balance between recreational, commercial, and industrial uses has been a challenge

Identifying their best uses and productivity and has stringent group of decision makers. Coastal erosion that causes shoreline to retreat.

Exposure is likely to increase as sea level rises with climate change. In some locations future changes in tropical storms and storm surges may further add to the risk of flooding. Projections of future change, particularly if they include quantified risk assessment, give governments the opportunity to plan sea defences and other infrastructure development

http://geology.uprm.edu/Morelock/morphol.htm

http://www.ozcoasts.org.au/indicators/mangrove_areas.jsp ( OzCoast 2010)

http://www.marine.tmd.go.th/marinemet_html/lect20.html

http://www.surfrider.org/structures/erosion.asp

http://www.marine.tmd.go.th/marinemet_html/lect20.html

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http://www.slideshare.net/sharmapd1/coastal-erosion-and-its-control

Sustainable activity

Conclusion

building with natural processes and relying on natural elements such as sands, dunes and vegetation to prevent erosive forces from reaching the backshore. These techniques include beach nourishment and sand dune stabilization.

To better understand how fast the beach are changing and address property loss due to erosion, or when beach nourishment makes sense.

Armoring the shoreline usually halts coastal erosion and protects property and structures, but on shorelines undergoing long-term retreat

However, the effectiveness of this structure is questioned as some of the wire cage are disoriented and causing some of the rocks to spill out.

However, one beach is more eroded compared to other. Some of the factors are:

Faces the ocean at proper angles will have higher erosion rate. As the angle more parallel to the coast, more sediment transport occurs.

Besides, higher wind strength especially during north-east monsoonal season from November to February would also accelerate the erosion.

Softer areas become eroded much faster than harder ones.