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This paper aims to develop a soil loss equation used within an equatorial climate (2,300 – 6,000 mm of annual rainfall) and hilly terrain based on measured data from the experiment concerning measured erosion outcomes, called Equatorial Soil Loss Equation (EQSLE). The equation under development should consider high equatorial rainfall intensities and challenging topographical conditions, thus introducing the new factors – Equatorial Rainfall Erosivity Factor (Reqt-factor) and Equatorial Slope Length Factor (Leqt-factor). The process included a photogrammetric method and image processing for raindrop size distribution and an experimental plot setup for a length differential study. The final equation has the form of A=Reqt⸱Leqt⸱S⸱K⸱C⸱P for soil erosion estimation in the equatorial region with the involvement slope and hilly terrain. The performance of the Reqt-factor and Leqt-factor are evaluated using the experimental data, and works of literature are carried out for the results. The formation of the two factors has addressed the challenges of high rainfall intensities and extreme terrain conditions faced by Peninsular Malaysia and East Malaysia. In future work, more case studies on the performance of soil loss rate prediction should be conducted to improve the overall performance of EQSLE as well as the respective factors.

The Bengoh Dam was constructed to secure reliable raw water supply to Kuching and its surrounding areas until 2030. However, the changes in river morphology along the Sarawak Kiri River after the Bengoh Dam construction remain unknown. This research was conducted to study the impact of Bengoh Dam construction on erosion and sedimentation along the Sarawak Kiri River using InfoWorks River Simulation (RS). The novelty is to identify and predict the short- and long-term geomorphology changes along the Sarawak Kiri River over the course of a year. Two scenarios were created, namely, a) with Bengoh Dam b) without Bengoh dam. The model with the Bengoh Dam scenario will be further investigated for ten years of simulation. The five locations selected for comparison and discussion are Bengoh Dam, Bengoh, Danu, Git Village and Batu Kitang. After the dam was built, sediment transport would be hindered, resulting in riverbed alterations. These changes are influenced by the location and proximity to the Bengoh Dam. Simulation results revealed that a huge amount of sediment will be accumulated behind Bengoh Dam. Both scenarios showed that there would be erosion at Bengoh, immediately after the Bengoh Dam, due to a phenomenon known as “Hungry Water.” It is novel to discover that the sedimentation rate at Danu, Git and Batu Kitang, which are located downstream of the Bengoh Dam, has drastically decreased. The capacity of the Batu Kitang Submersible Weir (BKSW) reservoir is unaffected by the constructed Bengoh Dam; hence no dredging must ensure the security of Kuching’s water supply.

Batu Kitang Submersible Weir (BKSW) was constructed to secure reliable water yield from the Sarawak Kiri River until 2010. However, ever-increasing water demand had outstretched the weir capacity. Upgrading work has been done to extend the weir height from 1.5 m to 2.5 m using interlocking concrete blocks to increase water storage capacity. However, the storage capacity and flood extend are unknown after the upgrading work. This study aimed to determine the effect of upgrading works on water storage capacity and floodplain coverage in the upper catchment using InfoWorks River Simulation (RS). Results revealed that weir height extension from 1.5 m to 2.5 m at BKSW had increased the water storage capacity from 1012 ML to 1499.62 ML, securing approximately 48% more water. Besides, maximum storage depth was also increased from 6.53 m to 7.53 m, and the distance of storage reservoir coverage from BKSW also increased from 8 Km to 16 Km. However, these increments would not lead to any significant impact on floodplain coverage upstream. It is novel to discover that a 1m weir height increase has extended BKSW service from 2010 to 2030 under a 1:50-year drought scenario. After 2030, various measures such as inter-basin raw water transfer should be implemented to increase the raw water supply and reduce water usage to ensure a sustainable water supply for Kuching City and its surrounding areas.

Samarahan has transformed from a small village into education hub for the past 2 decades. Rapid development and population growth had led to speedy growth in water demand. The situation is getting worse as the pipes are deteriorating due to pipe aging. Therefore, there is a need to study the adequacy of water supply and relationships among roughness coefficient (C) values in Hazen Williams’ Equation with head loss and water pressure due to pipe aging at Uni-Central, a residential area located at Samarahan Sarawak. Investigations were carried out with Ductile Iron, Abestos Cement and Cast Iron pipes at age categories of 0 - 10 years, 10 - 30 years, 30 - 50 years, 50 - 70 years and >70 years. Six critical nodes named as A, B, C, D, E and F were identified to study the water pressure and head loss. Model was developed with InfoWorks Water Supply (WS) Pro software. The impact of pipe aging and materials to water pressure and head loss was not significant at Nodes A, B, C and F. However, max water pressure at Nodes D and F were only reaching 6.30 m and 7.30 m, respectively for all investigations. Therefore, some improvement works are required. Results also show that Asbestos Cement pipe has the least impact on the head loss and water pressure, followed by Ductile Iron pipe and lastly Cast Iron pipe. Simulation results also revealed that older pipes have higher roughness coefficients, indicated with lower “C” values, thus increase the head loss and reduce the water pressure. In contrast, as “C” values increased, head loss will be reduced and water pressure will be increased.

Coastal erosion along Sarawak shoreline is getting serious in recent years due to the impact of climate change and global warming. Strong waves had washed away the land along the shore or beach and thus threatens the infrastructures that were constructed along Sarawak shoreline. Department of Irrigation and Drainage had adopted many methods to protect the shoreline including seawalls, breakwaters, geotextile tubes, concrete mass Labuan blocks, amour rocks and etc. The cheapest and most economic protection method is using armour rock. Besides, amour rock was found to be strong, durable, long-lasting, able to absorb and dissipate the waves before hitting on the shore. However, appropriate size of amour rocks to protect the shore is unknown. Therefore, this research is carried out to determine the appropriate armour rocks sizes for protecting the shoreline against the waves along Sarawak shoreline. The design methodologies are including determination of tidal levels, design wind speed, wind set-up, wave period, sea level rise, wave set-up, breaker height and lastly design armour rock sizes range. Shoreline Protection Manual and Hudson’s formula were adopted in this research to determine the appropriate sizes range of armour rocks. The study area was subdivided into 7 regions. Results revealed that southern part of Sarawak shorelines requires larger armour rock sizes compared to the northern region. The nominal size ranges of armour rocks for regions 1 and 2 are found to be 2112 mm, 1734 mm for region 3, and 1173 mm for regions 4, 5, 6 and 7. Results also revealed that the required armour rock sizes increase with the increment of Mean High Water Spring, nearshore slope gradients and structure slope. Besides, results also concluded that smaller amours rocks is sufficient to react against smaller waves, while bigger waves required bigger rocks for protecting the shoreline.

Missing rainfall data have reduced the quality of hydrological data analysis because they are the essential input for hydrological modeling. Much research has focused on rainfall data imputation. However, the compatibility of precipitation (rainfall) and non-precipitation (meteorology) as input data has received less attention. First, we propose a novel input structure for the missing data imputation method. Principal component analysis (PCA) is used to extract the most relevant features from the meteorological data. This paper introduces the combined input of the significant principal components (PCs) and rainfall data from nearest neighbor gauging stations as the input to the estimation of the missing values. Second, the effects of the combination input for infilling the missing rainfall data series were compared using the sine cosine algorithm neural network (SCANN) and feedforward neural network (FFNN). The results showed that SCANN outperformed FFNN imputation in terms of mean absolute error (MAE), root means square error (RMSE) and correlation coefficient (R), with an average accuracy of more than 90%. This study revealed that as the percentage of missingness increased, the precision of both imputation methods reduced.

Identifying the demographic factors that affect patterns is very important for determining drinking water sources within a community. Previous empirical studies mainly focussed on demographic factors affecting water demand in urban and semi-urban areas facing water shortage with little rainfall. However, studies on water consumption in tropical regions (average annual ∼4,000 mm) is limited. This study aims to investigate relationships between drinking water patterns and demographic factors for Kuching community, Sarawak, Malaysia. Survey data were collected from 100 respondents using structured questionnaires through mail, drop-off and telephone surveys in March–December 2016. Results revealed that drinking water patterns are significantly correlated with source, income and education level. 46% of respondents preferred tap water as their drinking water source, followed by 31% for in-home water-treatment devices, 19% chose bottled water and only 4% still drink raw water. In terms of income and education level, 25% of respondents with diploma, degree and postgraduate academic qualifications, quantified as higher income group, installed in-home water-treatment devices. 21% of respondents with monthly income more than RM2500 also initiated installation of in-home water-treatment devices. In contrast, age, gender and religion were found to have little affect on drinking-water consumption patterns.

Dyslexia is an indicating term for learning disorder due to the difficulty in identifying speech and sound of letters and words, causing reading difficulty. Most children with dyslexia utilise the greater part of their senses to connect with their environment. One of the difficulties faced by dyslexic children is their troubles expressing their emotion or thought through verbal or written communication due to limited vocabulary, which is caused by issues in perceiving letters, sound and importance of the word overall. Sight word reading is a methodology with various reading stages and fascinating diversion with the purpose to create a fun reading experience. Currently, the dyslexia centre (i.e., Learning and Resource Centre, Dyslexia Association of Sarawak) does not adopt Information and Communication Technology (ICT) in their teaching and learning processes. Hence, in this study, a mobile application that utilises sight word reading strategy has been produced with the aim to help children with dyslexia build up their reading aptitudes. Sight words reading strategy is incorporated into three different modules in the mobile application, namely short stories, rhymes and song verses, according to the suggestions given by the instructors at dyslexia centre. This paper presents the study on the effect of sight word reading strategy in mobile application. The main contributions of this study is the utilisation of sight word reading strategy to enhance the application features such as story, rhyme and song modules. An improved score board is added to monitor the progress of the child. This mobile application, Mr Read V2.0 has been tested at the Learning and Resource Centre, Dyslexia Association of Sarawak with the instructors and dyslexic children, together with their parents. The children obtained 28% improved test scores taken before and after using Mr. Read V2.0. The overall results of the testing session showed that 100% respondents, instructors, parents and children either agreed or strongly agreed that this mobile application can improve the reading skill from using the additional features added to Mr. Read V2.0. Sight word reading strategy that is incorporated into mobile application is an effective approach to help dyslexic children improve their reading skill.

This paper presents a novel metaheuristic artificial neural network (ANN) model, named as Bat optimisation neural network (BatNN), for spatial downscaling of long-term precipitation. This novel BatNN was developed due to the inefficiency of traditional ANNs in spatial downscaling of large-scale outputs from climate models. Input data are predictors from three climate models including HadCM3, ECHAM5 and HadGEM3-RA combined with observed precipitation collected from Kuching airport rainfall station. The output is the forecasted precipitation. Data from 1961 to 1990 were used for model training, while data from 1991 to 2010 were used for validation. Square root of correlation of determination (r), root mean square error (RMSE), mean absolute error (MAE) and Nash–Sutcliffe coefficient (E) are used to evaluate the models' performance. Results showed that through global and local searches, BatNN is able to avoid local optima trappings. The average r, RMSE, MAE and E for three climate models were yielded to 0.96, 1.69, 1.40 and 0.84, respectively. This reveals that BatNN is able to optimise and forecast long-term precipitation accurately.

Hydrologists are often encountered problem of missing values in a rainfall and runoff database. They tend to use the normal ratio or distance power method to deal with the problem of missing data in the rainfall and runoff database. However, this method is time consuming and most of the time, it is less accurate. In this paper, two neighbor-based imputation methods namely K-nearest neighbor (KNN) and Gaussian mixture model based KNN imputation (GMM-KNN) were explored for gap filling the missing rainfall and runoff database. Different percentage of missing data entries were inserted randomly into the database such as 2%, 5%, 10%, 15% and 20% of missing data. Pros and cons of these two methods were compared and discussed. The selected study area is Bedup Basin, located at Samarahan Division, Sarawak, East Malaysia. It is observed that the GMM-KNN imputation method results in the best estimation accuracy for the missing rainfall and runoff database.

Xinanjiang model, a conceptual hydrological model, is well known and widely used in China since 1970s. Xinanjiang model consists of large number of parameters that cannot be directly obtained from measurable quantities of catchment characteristics, but only through model calibration. Parameter optimization is a significant but time-consuming process that is inherent in conceptual hydrological models representing rainfall–runoff processes. This study presents newly developed Particle Swarm Optimization (PSO) and compared with famous Shuffle Complex Evolution (SCE) to auto-calibrate Xinanjiang model parameters. The selected study area is Bedup Basin, located at Samarahan Division, Sarawak, Malaysia. Input data used for model calibration are daily rainfall data Year 2001, and validated with data Year 1990, 1992, 2000, 2002 and 2003. Simulation results are measured with Coefficient of Correlation ( R ) and Nash-Sutcliffe coefficient ( E 2 ). Results show that the performance of PSO is comparable with the famous SCE algorithm. For model calibration, the best R and E 2 obtained are 0.775 and 0.715 respectively, compared to R =0.664 and E 2 =0.677 for SCE. For model validation, the average R =0.859 and average E 2 =0.892 are obtained for PSO, compared to average R =0.572 and average E 2 =0.631 obtained for SCE.

Problem statement: Sarawak River was a life-sustaining water source for the residents in Kuching City and surrounding areas. Raw water is treated at Batu Kitang Water Treatment Plant (BKWTP) that supplies more than 98% of the total water production in Kuching City. The raw water supply to BKWTP is not adequate to meet the ever increasing water demand. In order to overcome this problem, four projects had been implemented along Sarawak River for managing and securing water supply to BKWTP. Approach: These four projects are construction of 1.5m height storage weir across Sungai Sarawak Kiri river channel, Kuching Barrage and Shiplock, Bengoh Dam and Kuching Centralized Wastewater Management System (KCWMS). In 2005, 1.5 m height submersible weir was constructed across Sungai Sarawak Kiri channel for increasing the safe yield that can last until year 2010. Kuching Barrage and Shiplock were commissioned in 2000 as barrier to avoid the saline intrusion reaching upper catchment. 24 telemetry stations were installed along Sarawak River for monitoring and regulating the water level. This will preserve high quality water storage at upper catchment of Sarawak River. In year 2010, Bengoh Dam was constructed to ensure adequate raw water will be supplied to BKWTP for meeting the increasing water demand from 2010-2030. This reservoir will store 144 million m3 of fresh water covering reservoir area of 8.77km2. Beyond 2030, the water supply shall not depend solely on fresh water. Results: Black and grey water in Sarawak Catchment was treated through Kuching Centralized Wastewater Management System (KCWMS) and recycled for daily used. Conclusion: The treated water that comply Standard A water quality, can distribute for domestic, industrial and irrigation used in nearest future. This will reduce the water demand solely on raw water and create a sustainable living in Kuching City. Beyond 2030, a few alternatives are also proposed for conserving and securing water supply for Kuching city.

Over the past three decades, Particle Image Velocimetry (PIV), fundamentally based on pattern matching principles, has seen a rapid growth in its usage as a flow measurement technique. PIV is a ‘digital’ tracking process to measure the time taken for water to move from one point to the other. The particle displacements can be ascertained by measuring the movement of the fluid of interest from the images captured by a camera. In this study, PIV is employed to measure surface flow velocity. The flow velocity was obtained by analyzing the series of captured images using MatPIV codes. The experiment was carried out at Swinburne Sarawak Fluid Lab. Digital SLR camera model used is Nikon D40X which is capable of taking 5 frames per second. Various tracer particles were used for the experiments include food dye, beads and ping pong balls. The experiments were conducted in a SOLTEQ Sedimentation Tank. Through the implementation of a standardized correction factor, the corrected PIV velocity has an error margin less than 5% which is deemed to be fairly accurate. The PIV velocity (Vpiv) results showed to be in good agreement with the actual velocity (Vactual).

Malaysia is located in Southeast Asia and comprises 13 states and three federal territories. Malaysia has a population of about 28.3 million people (Department of Statistics Malaysia 2009). According to the Department of Statistics, Malaysia, for the year 2009, Malaysia’s gross domestic product (GDP) and gross national income per capita are USD 42.9 billion and USD 7,400 respectively. The latest unemployment rate is 3.6% (Department of Statistics Malaysia 2009).