Papers by Charles Bong
This paper presents the design of a tipping flush gate and its potential use in servicing open st... more This paper presents the design of a tipping flush gate and its potential use in servicing open storm sewers in terms of sedimentation management. The tipping flush gate was installed in a section of open concrete storm sewer located in a commercial area in Taman Pekaka, Nibong Tebal, Penang, Malaysia. Monitoring of the gate operation and performance was done from 14th November 2012 to 15th March 2013 covering the beginning and end of the wet season. The sediment profile inside the sewer was measured after each operation of the gate or rainfall event. Results showed that the gate was effective in reducing naturally accumulated sediment in the chosen sewer section. However, proper litter management is needed if the gate is to be implemented in open storm sewer systems. A design guideline for the usage of a tipping flush gate for open storm sewers is also presented in this paper.
Water Science & Technology, Oct 25, 2013
This paper highlights the preliminary study on the potential of a tipping flush gate to be used i... more This paper highlights the preliminary study on the potential of a tipping flush gate to be used in open storm drain to remove sediment. The investigation was carried out by using a plasboard model of the tipping flush gate installed in a rectangular flume. Steady flow experiment was carried out to determine the discharge coefficients and also the outflow relationship of the tipping flush gate. The velocity produced by the gate at various distances downstream of the gate during flushing operation was measured using a flowmeter and the velocity at all the points was higher than the recommended self-cleansing design available in the literature. Preliminary experiment on the efficiency of flushing was conducted using uniform sediment with d50 sizes of 0.81, 1.53 and 4.78 mm. Results generally showed that the number of flushes required to totally remove the sediment from the initial position by a distance of 1 m increased by an average of 1.50 times as the sediment deposit bed thickness doubled. An equation relating the number of flushes required to totally remove the sediment bed for 1 m with the sediment bed deposit thickness was also developed for the current study.
2013 IAHR World Congress, Sep 2013
This paper presents a case study of using a tipping flush gate for sediment flushing in an open c... more This paper presents a case study of using a tipping flush gate for sediment flushing in an open concrete storm drain. The study was conducted in an open concrete storm drain located in Taman Pekaka, Nibong Tebal, Penang, Malaysia with the objectives to study the scouring effect of flushing on sediment in the drain and also the feasibility to use tipping flush gate in an open drain system. The monitoring period was from 14 November 2012 to 15 March 2013. Sediment profile was measured after each operation of the gate or rainfall event using a simple stick. Results from the study shows that the flush gate is efficient in sediment removal with longer flushing operation time than the study on Hydrass gate in closed sewer system. However, problems such as debris caught at the gate, accumulation of debris behind the gate and water ponding causing mosquito breeding need to be address before the gate could be implemented for an open drain system.
The 7th International Conference on Sewer Processes and Networks (SPN7), Aug 28, 2013
This paper highlights the preliminary study on the potential of a tipping flush gate to be used i... more This paper highlights the preliminary study on the potential of a tipping flush gate to be used in open storm drain to remove sediment. The investigation was carried out by using a plasboard model of the tipping flush gate installed in a rectangular flume. Steady flow experiment was carried out to determine the discharge coefficients and also the outflow relationship of the tipping flush gate. The velocity produced by the gate at various distances downstream of the gate during flushing operation was measured using a flowmeter and the velocity at all the points was higher than the recommended self-cleansing design available in the literature. Preliminary experiment on the efficiency of flushing was conducted using uniform sediment with d50 size of 0.81 mm. Results generally showed that the number of flushes required to totally remove the sediment from the initial position by a distance of 1 m increased by an average of 1.45 times as the sediment bed thickness doubled. Results from this preliminary study could provide better understanding of the tipping flush gate characteristics for further study in an on site open storm drain and also for validation of numerical model for the analysis of the performance of flushing.
Urban Water Journal, 2014
This paper highlights the results of sediment size characteristics and deposition analysis on 24 ... more This paper highlights the results of sediment size characteristics and deposition analysis on 24 sediment samples from urban concrete drains in Kuching City. Further sampling from surrounding urban towns outside Kuching City and Penang were done for comparison. Samples were collected randomly from three land-use types (residential, commercial and industrial). Sieve analysis results had shown that most of the total samples collected (51 out of 57) were predominantly sand, followed by gravel; while silt and clay were the minor components. Unimodal characteristics were observed in 46 samples while 11 samples showed bimodal characteristics. Of the total 46 unimodal samples, 39 showed non-uniform distribution with tendency to skew to the right. Due to this, the mode grain size with characteristic diameter d 45 is suggested as a much better representative size than the conventional median size d 50 . Factors affecting sediment deposition characteristics in urban drains are also discussed.
The current study aims to verify the existing equations for incipient motion for a rigid rectangu... more The current study aims to verify the existing equations for incipient motion for a rigid rectangular channel. Data from experimental work on incipient motion from a rectangular flume with two different widths, namely 0.3 and 0.6 m, were compared with the critical velocity value predicted by the equations of Novak & Nalluri and El-Zaemey. The equation by El-Zaemey performed better with an average discrepancy ratio value of 1.06 compared with the equation by Novak & Nalluri with an average discrepancy ratio value of 0.87. However, as the sediment deposit thickness increased, the equation by El-Zaemey became less accurate. A plot on the Shields Diagram using the experimental data had shown the significant effect of the sediment deposit thickness where, as the deposit becomes thicker, the dimensionless shear stress θ value also increased. A new equation had been proposed by incorporating the sediment deposit thickness. The new equation gave improved prediction with an average discrepancy ratio value of 1.02.
Proceedings of 2nd International Conference on Water Resources (ICWR2012)
Two figures are depicted-emanating from the findings of researchers from the Faculty of Engineeri... more Two figures are depicted-emanating from the findings of researchers from the Faculty of Engineering, University of Malaysia Sarawak in the article entitled Tools for Integrated River Flood Management (Hydraulics Modeling and Logical Framework Analysis), (pp. 47-60). In the context of the various problems attributed by climate changes, river basin management is vital in 'achieving the protection, improvement and sustainable use of the water environment'. This article discusses how hydraulic simulation could be used as a supporting tool in planning and developing a framework for river management such as Integrated Flood Management for a river basin. It also demonstrates how a hydraulic model for the Sarawak River Basin was run using InfoWorks River Simulation software. The model was used as a tool to provide necessary decision parameters in developing the logical framework which could act as a guide for planning involving various stakeholders' participation.
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Silent response given by students when being posed questions or asking for their opinion on a sub... more Silent response given by students when being posed questions or asking for their opinion on a subject matter is a situation faced by most lecturers when conducting classes, especially with Asian students. Studies carried on the behaviour of Asian students have shown that these groups have different learning styles and method compared to western students. Unlike the western culture, these Asian students are less active in participation during the learning activities in class. This paper will discuss the background of this issue, factors contributing to this issue and finally proposing some of the methods that could be use by lecturers in encouraging students to speak up in class.
2007 Customer Service …, Jan 1, 2007
INFOWORKS WS APPLICATIONS FOR URBAN WATER DEMAND MANAGEMENT: A CASE STUDY OF KUCHING CITY, SARAWA... more INFOWORKS WS APPLICATIONS FOR URBAN WATER DEMAND MANAGEMENT: A CASE STUDY OF KUCHING CITY, SARAWAK, MALAYSIA. Frederik Josep Putuhena, Darrien YS Mah, Salim Said, Charles HJ Bong 2007 ...
The IUP Journal of Soil and Water …, Jan 1, 2010
Existing literature suggests that Darcy's law is not valid in layers of different de... more Existing literature suggests that Darcy's law is not valid in layers of different degrees of decomposed peat soil. The present study attempts to validate the applicability of Darcy's law by comparing the velocity predicted by it and the velocity obtained through experiment for a peat soil column and also to assess the changes of hydraulic conductivity, k, with the depth of peat soil layers. The suitability of Izbash's law to predict the flow through peat soil column of different degrees of decomposition was tested by determining the n value (Izbash's ...
World Academy of …, Jan 1, 2009
The distressing flood scenarios that occur in recent years at the surrounding areas of Sarawak Ri... more The distressing flood scenarios that occur in recent years at the surrounding areas of Sarawak River have left damages of properties and indirectly caused disruptions of productive activities. This study is meant to reconstruct a 100-year flood event that took place in this river basin. Sarawak River Subbasin was chosen and modeled using the one-dimensional hydrodynamic modeling approach using InfoWorks River Simulation (RS), in combination with Geographical Information System (GIS). This produces the hydraulic response of the river and its floodplains in extreme flooding conditions. With different parameters introduced to the model, correlations of observed and simulated data are between 79% -87%. Using the best calibrated model, flood mitigation structures are imposed along the sub-basin. Analysis is done based on the model simulation results. Result shows that the proposed retention ponds constructed along the sub-basin provide the most efficient reduction of flood by 34.18%.
The Journal, Jan 1, 2008
The practical interest to study the flow in compound channel section arises from the necessity fo... more The practical interest to study the flow in compound channel section arises from the necessity for accurate discharge predictions during flood events and for a reliable stage discharge relation for flood control measures and management schemes. It has been long realized that traditional hydraulic methods of channel subdivision are inadequate for discharge calculation due to the significant interaction between main channel and flood plain that previously rarely taken into account of. This paper presented the results of experimental investigations carried out on a small scale non-symmetrical compound channel with rough flood plain in order to compare the different methods available for discharge prediction in a compound channel. The weighted divided channel method (WDCM) has been used to check the validity of the horizontal division method and the vertical division method in predicting discharge. Results from this experimental investigations have shown that for non-symmetrical compound channel with wider flood plain, the horizontal division method provide the more accurate predictions of discharge while for narrower flood plain, the vertical division is more accurate.
Journal of the Institution of Engineers Malaysia, IEM, Jan 1, 2007
The practical interest to study the flow in compound channel section arises from the necessity fo... more The practical interest to study the flow in compound channel section arises from the necessity for accurate discharge predictions during flood events and for a reliable stage discharge relation for flood control measures and management schemes. It has been long realized that traditional hydraulic methods of channel subdivision are inadequate for discharge calculation due to the significant interaction between main channel and flood plain that previously rarely taken into account of. This paper presented the results of experimental investigations carried out on a small scale non-symmetrical compound channel with rough flood plain in order to compare the different methods available for discharge prediction in a compound channel. The weighted divided channel method (WDCM) has been used to check the validity of the horizontal division method and the vertical division method in predicting discharge. Results from this experimental investigations have shown that for non-symmetrical compound channel with wider flood plain, the horizontal division method provide the more accurate predictions of discharge while for narrower flood plain, the vertical division is more accurate.
IAENG International journal of …, Jan 1, 2007
This study aims to improve water level prediction at Bedup River with estimations made to absent ... more This study aims to improve water level prediction at Bedup River with estimations made to absent precipitation data, both using Artificial Neural Network (ANN). Studies to predict water level in the state of Sarawak, Malaysia have been actively carried out. However, among problem faced was absent precipitation readings, which inevitably affected water level precipitation accuracies. Backpropagation properties of ANN was used in the study to predict both missing precipitation and water level. ANN model developed in this study successfully estimates missing precipitation data of a recorder in Bedup River, Sarawak with 96.4% accuracy. The predicted values of precipitation were then used to forecast water level of the same gauging station and yielded accuracy value of 85.3%, compared to only 71.1% accuracy of water level prediction with no estimation made to its missing precipitation data. These results show that ANN is an effective tool in forecasting both missing precipitation and water level data, which are utmost essential to hydrologists around the globe.
Resources, Conservation and …, Jan 1, 2009
A pilot project of greywater ecological treatment is established in Kuching city since 2003. Such... more A pilot project of greywater ecological treatment is established in Kuching city since 2003. Such treatment facility opens up an opportunity of wastewater reclamation for reuse as secondary sources of water for non-consumptive purposes. This paper aims in exploring the potential of the intended purposes in the newly developed ecological treatment project. The modeling process of using a mathematical representation of the real system is commonly performed to evaluate a proposed system. By using network simulations, which replicate the dynamics of a proposed system, problems can be anticipated and solutions can be evaluated before time, money and materials are invested in a real-world project. Efforts are made to carry out a hydraulic modeling of a hypothetical greywater recycling system as an integrated part of the Kuching urban water supply using the Wallingford Software model, InfoWorks Water Supply (WS). The modeling efforts where the greywater is treated, recycled and reused in the domestic environment have shown water saving of about 40%. This model assists the researcher to evaluate the performance of the recycling system in the context of shifting towards more integrated water resources management.
Papers/Theses by Charles Bong
This paper aims at evaluating whether the design criteria based on critical velocity or critical ... more This paper aims at evaluating whether the design criteria based on critical velocity or critical shear stress is more suitable for the purpose of self-cleansing in open concrete drain. Experimental work on incipient motion was done in rectangular flume with two different widths namely 0.3 m and 0.6 m. The results from the incipient motion experiment were compared with a short-term on-site observation on the erosion and deposition pattern in a stretch of urban open concrete drain located in a residential area in Kuching, Sarawak, Malaysia. Comparison with site observation has shown that the relationship between mean critical velocity with median grain size; 0.075 0.246 50 V d c developed from the experimental work predicts reasonably well when erosion starts to occur on site. The critical shear stress values obtained from the experimental work tend to under predict when compare with the values from site observation. Thus, the mean critical velocity is a much better criterion to be used in the design for open concrete drain for self cleansing purpose.
This paper highlights the results of sediment size characteristics and deposition analysis on 24 ... more This paper highlights the results of sediment size characteristics and deposition analysis on 24 sediment samples from urban concrete drains in Kuching City. Further sampling from surrounding urban towns outside Kuching City and Penang were done for comparison. Samples were collected randomly from three land-use type (residential, commercial and industrial). Sieve analysis results had shown that most of the total samples collected (51 out of 57) were predominantly sand, followed by gravel; while silt and clay were the minor components. Unimodal characteristics were observed in 46 samples while 11 samples showed bimodal characteristics. Of the total 46 unimodal samples, 39 showed non-uniform distribution with tendency to skew to the right. Due to this, the mode grain size with characteristic diameter d45 had been suggested to be a much better representative size than the conventional median size d50. Factors affecting sediment deposition characteristics in urban drains had also been discussed.
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Papers by Charles Bong
Papers/Theses by Charles Bong