Beach response due to the pressure equalization modules (PEM) system

Coastal erosion is a significant problem with dramatic effects on the coastline. There is an urgent need to introduce new and cost-effective measures that can mitigate the impacts on the shoreline. This study has been initiated to investigate the response of the beach at Teluk Cempedak due to the beach nourishment and Pressure Equalization Modules (PEM) system. The objectives of this study are the determination of closure depth and effectiveness of the system in treating the erosion process. The depth of closure was examined using both data from a series of beach profile surveys and from empirical formulae. The widely accepted Fixed Depth Change (FDC) method was explored and the hc before and after the installation of PEM system was investigated. The research found that multiple closure points can occur along the profile lines. The closure depth after the installation of PEM system was found to be deeper and the closure point is further seaward at the southern part of the beach. The Hellemeier’s equation over predict hc by 76 %, however it reveals that the equation is still robust in determining an upper limit of hc. The simplified equation was developed at Teluk Cempedak beach in predicting closure depth and can be equated to 0.98 times H0.137. From the survey data, it is found that after three years, the total sand volume and beach elevation are significantly higher in PEM areas. Generally, the result presented indicates the decreasing value of rate of erosion. Thus it revealed that PEM system is able to stimulate accretion of sand and yet slow down the erosion process. However, based on the sand volume distribution pattern, after three years, it is obviously seen that the accretion of sand occurring at the northern part while erosion process is taking place in the southern part of the beach. Based on the distribution pattern of bed elevation over the chainage, overall, the upper part of the beach is convex unlike earlier i.e before the installation of PEM system, where the beach was low and concave. This phenomena indicates that the system contribute to a significant accretion of sand and thus created a higher beach level at about 10 m to 55 m towards the sea. However, this trend only can be seen at a certain chainage. The PEM efficiency in terms of increment in bed elevation can only be observed at CH 400 till CH 800 while at CH 900 towards the south, the efficiency is decreasing. This shows that the accretion of sand is only occurring at the northern part and the beach is eroding at the southern part. Therefore, based on the available four years record of data, there is a certain part of the beach benefiting from the PEM system. However, some parts are still experiencing the erosion process

Natural headland sand bypassing: towards identifying and modelling the mechanisms and processes

This study contributes to the understanding of the mechanisms and processes of sand bypassing in artificial and non-artificial coastal environments through a numerical modelling study. Sand bypassing processes in general are a relevant but poorly understood topic. This study attempts to link the theory and physics of sand bypassing processes around headland and engineered structures which is significantly important in definition of coastal sedimentary budget. The main questions are how can we model sand bypassing processes and if the modelled sand bypassing processes represent the actual sand bypassing processes. In this study, it is shown that a process-based model can be used to simulate the processes of sand bypassing around groyne and headland structures. The morphological model developed in this study is useful to increase understanding of the natural sand distribution patterns due to combination of engineering efforts and natural coastal processes

Hydraulic performance and modelling of pressurized drip irrigation system

This study was conducted at Laman Sayur, Malaysia Agro Exposition Park Serdang (MAEPS), to investigate the hydraulic performance of a small-scale drip irrigation system. The modelling was carried out using EPANET software to understand how the drip irrigation system is operated. Model results show that the errors are small, i.e., 2.2% and 3.0% for pressures, and 1.7% for discharge in lateral pipe 1 and lateral pipe 2. The root mean square error (RMSE) and the mean bias error (MBE) for discharge were recorded at 0.04 L/h and 0.03 L/h for lateral pipe 1 and 0.04 L/h and 0.02 L/h for lateral pipe 2. RMSE and MBE for pressure were recorded at 0.61 m and 0.68 m for lateral pipe 1, and 0.79 m and 0.68 m for lateral pipe 2, respectively. These results show that the model yields good performance. For hydraulic performance, the field measurement was conducted with four operating pressures: P1 (15.3), P2 (20.4), P3 (25.5), and P4 (28.6) meters. The hydraulic parameters evaluated were the coefficient of uniformity (CU), the emission uniformity (EU), the coefficient of variation (CV), and the emitter flow variation (EFV). The operating pressure during the measurement is constant according to the specified pressure. The results show that CU, CV, and EU are in the excellent classification, and values of CU and EU have more than 95% efficiency. The value for CV is below 0.03, which is excellent. The EFV is 10% when operating at 25.5 m and 15.3 m and is considered desirable. On the other hand, for the 28.6 m and 15.3 m operating pressures, the EFV parameters were recorded at 13.6% and 10.29%, respectively, and are classified acceptable. This study concluded that the operating pressures, P2 (20.4 m) and P3 (25.5 m), were performed under excellent classification for all hydraulic parameters evaluated. Based on the outputs from the model, it is inferred that the existing drip irrigation system at Laman Sayur MAEPS is operated in an over-powered state. With the current pump power consumption, the irrigation system could be operated at a minimum of four times the capacity of the existing irrigation system. To reduce the power consumption, it is suggested that the system is operated at a lower pumping power. This would minimize the operating costs especially for the development of a new drip irrigation system that has the same capacity as the drip irrigation system that is currently being operated at Laman Sayur, MAEPS Serdang

Planform stability of embayed beaches along the east coast of Peninsular Malaysia

The presence of embayed beaches along the East coast of Peninsular Malaysia has proven the significant influence of wave variability due to the Northeast monsoon. These beaches, which some of them are among the popular beaches for tourism and recreational activities, have not been categorised according to its planform stability. Categorising this type of beach is a preliminary step towards the long-term shoreline management plan. This study presents the outputs of the application of the parabolic bay model to satellite images of the embayed beaches. It focuses on the determination of the total number of embayed beaches along the East coast of Peninsular Malaysia including identification of beach planform stability using the model of equilibrium bay beach (MEPBAY) program. The model was used as a tool to propose engineering solutions and to investigate the applicability of the existing coastal structures for the beach in dynamic or unstable state. MEPBAY analysis showed that out of 51 beaches - 26 of them are dynamic, 23 are static and another two are in unstable state of planform equilibrium. Beaches with static planform equilibrium include Batu Buruk beach, Irama beach, Resang cape, Jemaluang beach and Kg Punggai in which the beaches undergo no addition or erosion of sediment towards the bay and littoral drift of the beach is almost non-existent. Results presented indicated that beaches with dynamic equilibrium state was achieved when the shoreline experiences degradation or undergo erosion due to the changes in the equilibrium orientation and shoreline planform of the bay as shown by Senok beach, Jara beach, Sedili cape, Cherating beach, Endau-Rompin beach, Bukit Tengah beach, Kalung bay and Teluk Lipat beach. Unstable equilibrium embayed beaches on the other hand, is a condition when the curved planform of the beach experienced accretion in the lee accompanied by erosion downdrift as showed by the Tok Jembal beach. This condition is a result of wave sheltering or changes in the geometric configuration of the beach. The numerical modelling exercises through MEPBAY have given us an understanding on the variation of planform stability towards the embayed beaches morphodynamics

The planform stability of embayed beaches on the west coast of Peninsular Malaysia

Embayed beaches can be found along the West coast of Peninsular Malaysia and they are subject to beach’s dynamic changes. Some part of the coast along the West coasts have experienced severe erosion for several decades, in spite of the construction of various coastal defence structures. Therefore, it is crucial to predict the stability of embayed beaches along the West coast of Peninsular Malaysia. The planform stability of embayed beaches was established by applying the MEPBAY model. It was found that the total number of embayed beaches along the West coast of Peninsular Malaysia is 139 with 73 % were natural embayed beaches and 27 % were artificial embayed beaches. From the analyses, out of the 139 embayed beaches; 82 % were in static equilibrium and 18 % were in dynamic state. The causes of the instability of embayed beaches are the topography of the embayed beach, discrepancies in the design of previous coastal structures, influenced by wave climate as well as human intervenes without prior investigation of the biological and physical effects towards the beach. Furthermore, the applicability of engineering solutions applied on embayed beaches that are in either dynamic equilibrium can be predicted using MEPBAY programme

Waste cooking oil as a sustainable bio modifier for asphalt modification: a review

The rising demand for non-renewable resources such as asphalt binder is a significant issue in the pavement industry. Flexible pavement consumes a significant amount of asphalt binder, which has become a major issue in terms of environmental sustainability and from an economics viewpoint. Hence, researchers strive to find other alternatives to solve these problems, to enhance the performance and lifespan of flexible pavement. Biomass-based bio-oil, such as waste cooking oil (WCO), as a modifier has illustrated favorable effects for asphalt binder and mixture. However, in the pavement industry, its adoption as a modifier is still in an empirical stage. Hence, this paper aimed to give an overview by analyzing literature in-depth to reveal the potential of WCO as a modifier in the pavement industry. The low- and intermediate-temperature performance of the WCO-modified asphalt binder are superior. However, it compromises physical properties and high-temperature performance. Hence, it can be improved by controlling the quality of WCO or by further modification by additives such as ground tire rubber (GTR) and waste plastic. This paper also attempts to review available and potential physical and chemical technologies to minimize the negative effects of free fatty acid (FFA) and water content of WCO on modified asphalt binder properties. For WCO-modified asphalt mixture, the overall performance depends on the dose, quality of WCO, and type of additive added in the WCO-modified binder. Finally, future recommendations are provided to broaden the scope of WCO as a modifier in the forthcoming sustainable pavement industry

Short-term analysis of shoreline changes detection along Pahang coastline, Malaysia: an application of digital shoreline analysis system (DSAS)

Erosion can cause a major problem and has impacted the livelihoods of residents that reside along the coastline zone. Coastal erosion is known as a permanent loss of land or habitat. The use of Geospatial Information System (GIS) to understand changes can provide large scale understanding of the coastal dynamic along Pahang coastline. Shortwave Infrared 1 (SWIR_1) from Sentinel-2 MSI in the delineation of shoreline has helped in providing changes for short-term shoreline analysis from 2018 to 2021. ENVI 5.1 has been used to extract the shoreline from the SWIR_1 Sentinel-2 band. The extracted shorelines were then processed using the Digital Shoreline Analysis System (DSAS) and the rate of changes were calculated statistically using Net Shoreline Movement (NSM), Endpoint Rate (EPR), Linear Regression Rate (LRR), and Weighted Regression Rate (WLR). The LRR results were fitted to determine the shoreline changes compared to other analyses. The normalized root means square errors were calculated for the study sites by comparing the coordinates taken along the shoreline with the coordinates from the Sentinel-2 Imagery 2021. The model results showed about 46.36% of the northern sector of Pahang coastlines are facing erosion while in the southern sector about 35.77% are experiencing erosion. The LRR results were compared with the previous study conducted by the Department of Irrigation and Drainage Malaysia for the National Coastal Erosion Study (2015). The highly impacted areas are listed and recommendations are made according to the decision matrix for each area, beneficial to policy-makers in future decision making