Abdul Halim Ghazali

Universiti Putra Malaysia | UPM · Department of Civil Engineering

The increases in extreme rainfall could increase the probable maximum food (PMF) and pose a severe threat to the critical hydraulic infrastructure such as dams and food protection structures. This study is conducted to assess the impact of climate change on PMF in a tropical catchment. Climate and infow data of the Tenmengor reservoir, located in...

The increases in extreme rainfall could increase the probable maximum food (PMF) and pose a severe threat to the critical hydraulic infrastructure such as dams and food protection structures. This study is conducted to assess the impact of climate change on PMF in a tropical catchment. Climate and infow data of the Tenmengor reservoir, located in t...

Increased extreme rainfall due to climate change will increase the probable maximum flood (PMF) and pose a severe threat the critical hydraulic infrastructure like hydroelectric and flood protection dams. As the rainfall extremes in tropical regions are highly sensitive to global warming, increase PMF can be much higher in the tropics. A study has...

Featured Application: The application of this study contributes on the urban stormwater channels that reduce the required length of such channel and thereby reduce the land use, construction and maintenance-related costs. Abstract: The check dams in grassed stormwater channels enhance infiltration capacity by temporarily blocking water flow. Howeve...

Accumulation of the sediment in the stream of the diversion channels adversely affects its operational systems. Diversion channels are often constructed perpendicular to the main river. In this study, the water flow and sediment transport in the diversion channel with different angles were investigated in an attempt to maximize water discharge and...

Featured Application: The application of this study contributes on the urban stormwater channels that reduce the required length of such channel and thereby reduce the land use, construction and maintenance-related costs. Abstract: The check dams in grassed stormwater channels enhance infiltration capacity by temporarily blocking water flow. Howeve...

Featured Application: The application of this study contributes on the urban stormwater channels that reduce the required length of such channel and thereby reduce the land use, construction and maintenance-related costs. Abstract: The check dams in grassed stormwater channels enhance infiltration capacity by temporarily blocking water flow. Howeve...

Featured Application: The application of this study contributes on the urban stormwater channels that reduce the required length of such channel and thereby reduce the land use, construction and maintenance-related costs. Abstract: The check dams in grassed stormwater channels enhance infiltration capacity by temporarily blocking water flow. Howeve...

Permeable channels are commonly adopted for urban stormwater management as an infiltration device. However, in the design of such channels, the effects of flow hydraulic parameters (i.e. water level, channel cross section and flow velocity) on the infiltration capacity of a permeable channel have usually been neglected. In this study, the variation...

Earth-fill dams are the most common types of dam and the most economical choice. However, they are more vulnerable to internal erosion and piping due to seepage problems that are the main causes of dam failure. In this study, the seepage through earth-fill dams was investigated using physical, mathematical, and numerical models. Results from the th...

In stormwater management, it is important to accurately quantify the infiltration rates to solve urban runoff-related problems. This study proposes a method to improve estimates of the infiltration rate in permeable stormwater channels. As part of the analysis, five infiltration models were evaluated: the Kostiakov, Horton, modified Kostiakov, Phil...

The study aims to evaluate the long-term changes in meteorological parameters and to quantify their impacts on water resources of the Haro River watershed located on the upstream side of Khanpur Dam in Pakistan. The climate data was obtained from the NASA Earth Exchange Global Daily Downscaled Projection (NEX-GDDP) for MIROC-ESM model under two Rep...

The use of permeable stormwater channels has introduced concerns over the effects of infiltration on the hydraulic behavior of their flow and the effects of flow hydraulic conditions (e.g., the water level, channel section, flow velocity, and vegetation) on the channel infiltration capacity. A check dam system provides backwater ponding, which incr...

This paper presents the results of an experimental study in which an acoustic Doppler velocimeter (ADV) was used to monitor the longitudinal velocity profiles and discharge proportions in a channel with a mobile bed and banks. The resultant channel bed elevations were also monitored. The physical model consisted of a channel with two branches and a...

Digital elevation models (DEMs) are essential to provide continuous terrain elevation for water surface elevation (WSE) with a variety of horizontal and vertical accuracies in flood inundation modelling. The WSE forecasting depends on the appropriateness of the DEM data used. The comparative methodology is applied to various DEM sources: LiDAR and...

Water discharge is the main parameter in hydraulic modeling for flood hazard assessment. However, the unavailability of data on discharge and observed river morphologies resulted in erroneous calculations and irregularities in flood inundation mapping. The objectives of this study are (i) to investigate uncertainties of hydraulic parameters (width,...

Factors affecting the infiltration rate have been studied fairly well by many researches; however, the effects of the cross section of a permeable stormwater channel on the surface water depth reduction due to infiltration and seepage have largely been neglected. In the present study, towards improving the efficiency of permeable channels, the effe...

Diversion flows from rivers or main channels affect bed morphology and cause erosion and sedimentation at the diversion channel junction. In a diversion channel flow system, the scour depth and scour length are considered important parameters and should be taken into account during the project construction stage because it affect the stability of m...

Maximization of infiltration and seepage rates is important to better control the quantity of stormwater to foster sustainable urban stormwater management. In this study, the effect of the cross-sectional flow area of a permeable channel on seepage rate was investigated to improve the efficiency of permeable stormwater channels. Physical models und...

Maximization of infiltration and seepage rates is important to better control the quantity of stormwater to foster sustainable urban stormwater management. In this study, the effect of the cross-sectional flow area of a permeable channel on seepage rate was investigated to improve the efficiency of permeable stormwater channels. Physical models und...

Although hydropower generation has obvious advantages, but many of hydropower reservoir systems are still not operated efficiently and being operated based on experience. It is noticeable that even small improvement in operational rules can improve the efficiency of hydropower system. Since the output of hydropower generation depends on water relea...

The objective of this research was to investigate the capability of rigid Polyvinylchloride (PVC-U) pipes to sustain axial loads. The behavior of PVC-U pipes specimens subjected to short-term uniaxial compression loads were experimentally investigated. Results of the load-displacement tests on pipes of different wall thickness, diameter, and specim...

Discharge is traditionally measured at gauge stations located at discrete positions along the river course. When the volume of water discharge is higher than the river bank, inundation to adjacent land occurs. Flood inundation mapping has largely relied on in situ discharge data. However, it cannot be accessed at ungauged sites. In recent literatur...

The study of dam-break analysis is considered important to predict the peak discharge during dam failure. This is essential to assess economic, social and environmental impacts downstream and to prepare the emergency response plan. Dam breach parameters such as breach width, breach height and breach formation time are the key variables to estimate...

Information gained from drought analysis can serve as the basis for water resources planning and management under the prevailing climate change condition especially at the basin scale. The aim of this work is to apply two meteorological drought indices - Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SP...

Safeguarding groundwater from pollution is largely a global political decision. These decisions are basically supported by DRASTIC (D=Depth to water, R=Recharge, A=Aquifer media, S=Soil media, T=Topography, I=Impact of vadose zone, C=Hydraulic conductivity) analysis. Furthermore, water quality index (WQI) is an effective tool for groundwater qualit...

In this paper, an ensemble method, which demonstrated efficiency in GIS based flood modeling, was used to create flood probability indices for the Damansara River catchment in Malaysia. To estimate flood probability, the frequency ratio (FR) approach was combined with support vector machine (SVM) using a radial basis function kernel. Thirteen flood...

All groundwater is vulnerable to pollution, but the level of susceptibility depends on the spatial peculiarities of a region. Among the numerous vulnerability assessment methodologies, the geographical information system-based DRASTIC model is the most sophisticated and achieves reliable results even in complex areas. Fractured-rock aquifers are no...

Several techniques have been used for estimation of peak outflow from breach when dam failure occurs. This study proposes using a generalized regression artificial neural network (GRNN) model as a new technique for peak outflow from the dam breach estimation and compare the results of GRNN with the results of the existing methods. Six models have b...

Analysis of trends in temperature can provide important information required for the understanding of climate in any geographical setting. In this study, trends of mean (TMEAN), maximum (TMAX) and minimum (TMIN) air temperature series were investigated based on monthly, seasonal and annual timescales over the Niger-South Basin (NSB) during 1948–200...

Increasing greenhouse gas concentrations can cause future changes in the climate system that have a major impact on the hydrologic cycle. To realize and predict future climate parameters, the Atmosphere-Ocean Global Climate Models (AOGCMs) are common employed tools to predict the future changes in climate parameters. The statistical downscaling met...

The use of an artificial neural network (ANN) is becoming common due to its ability to analyse complex nonlinear events. An ANN has a flexible, convenient and easy mathematical structure to identify the nonlinear relationships between input and output data sets. This capability could efficiently be employed for the different hydrological models suc...

A complex flow pattern represented by branching channel flow is simulated using BASEMENT software and verified by the experimental data. The numerical computation is based on Shallow Water Equations (SWE). The model includes rectangular main and branch channels with a 1:2 bed width aspect ratio. A sub-critical flow with three different branching an...

Knowledge of fractures and their connectivity in geologic media is paramount to groundwater resource management. However, the theory of connectivity between the fractures and their measurement techniques, and its application in modelling are still under great debate. Various studies indicated that the aquifers of the basement complex rocks in Kano...

This study was carried out to identify the optimum dosage of different types of polymer for sewage sludge conditioning to achieve high dewaterability. The sludge conditioners used in this study were synthetic polymers; cationic polymer (Magnafloc LT 22S), anionic polymers (Magnafloc LT 25 and Magnafloc LT27), and nonionic polymer (Magnafloc LT 20)....

The efficient utilization of hydropower resources play an important role in the economic sector of power systems, where the hydroelectric plants constitute a significant portion of the installed capacity. Determination of daily optimal hydroelectric generation scheduling is a crucial task in water resource management. By utilizing the limited water...

The main objective of this study was to determine the reliability of using microfiltration system which is composed of a coagulant such as ferric chloride (pretreatment substance) and hollow fibre membrane as filtering medium for improving water quality. In this study, raw water samples were collected from a lake located at the Faculty of Engineeri...

Rising global temperatures have threatened the operating conditions of Batang Padang hydro power reservoir system, Malaysia. It is therefore crucial to analyze how such changes in temperature and precipitation will affect water availability in the reservoir in the coming decades. Thus, to predict future climate data, including daily precipitation,...

One of the main costly problems at wastewater treatment plants is the treatment of sludge, which is responsible for about 50% of the total operating cost of the whole treatment system. Chemical conditioning of sludge before dewatering is often necessary to increase the process efficiency of dewatering devices. Moringa oleifera seeds were evaluated...

Moringa oleifera has been proven to be an effective natural coagulant, a suitable alternative to aluminum sulfate, in water treatment. Several studies have been carried out to obtain the efficiency of M. oleifera as a coagulant using different extraction techniques in obtaining the active ingredient, such as, water and salt (different types of salt...

The effectiveness of freeze-dried Moringa oleifera (MO) seeds powder in the coagulation of synthetic wastewater was studied. Three modes of extraction were introduced, namely distilled water-extracted freeze-dried M. oleifera (FD-DW MO), salt-extracted freeze-dried M. oleifera (FD-KCl MO), and distilled water-extracted freeze-dried M. oleifera with...

Groundwater vulnerability assessment is an important task in water resources and land management. The most sophisticated among the vulnerability assessment techniques is the GIS-based DRASTIC model. However, despite its popularity, it is marred with excessive subjectivity glitches; little research has been conducted to address the shortcomings asso...

In this study, a few field experiments were conducted on a simple solar still and water quality analyses were done in laboratory to check the contaminants removal efficiency from raw water samples. A few water quality parameters such as pH, redox, electrical conductivity (EC), salinity, total dissolved solids (TDS), Escherichia coll and arsenic for...

Various hydrological and meteorological variables such as rainfall and temperature have been affected by global climate change. Any change in the pattern of precipitation can have a significant impact on the availability of water resources, agriculture, and the ecosystem. Therefore, knowledge on rainfall trend is an important aspect of water resour...

Seawater intrusion is threatening freshwater resources in coastal regions worldwide. Modelling this phenomenon can help in the management and control of such problems. This study presents a numerical model of seawater intrusion in a semi-confined aquifer in the lowland area of the Langat basin, Selangor, Malaysia, where groundwater is the only sour...

Vegetation porosity in a vegetated channel has been identified as the main parameter that contributes to the flow behaviour and resistance in the channel. Estimation of vegetation porosity is quite a challenging task due to the diverse characteristics of vegetation. In this study, several porosity measurement methods based on vegetation frontal are...

Vegetation plays an important role in transport and settling of suspended sediment in natural waterways. In this study, effectiveness of emergent vegetation in an open channel for the removal of Total Suspended Solids (TSS) and turbidity is empirically investigated. To this end, response surface methodology (RSM) was applied to optimize three varia...

Many researchers have studied evaporation reduction of open water bodies using inexpensive locally available materials. However, such studies lacked information on the effects of the covers on water quality. This study focused on the assessment of the capability of floating and structural covers to reduce evaporation from open water bodies in a hum...

Uncertainty in depth–duration–frequency (DDF) curves is usually disregarded in the view of difficulties associated in assigning a value to it. In central Iran, precipitation duration is often long and characterized with low intensity leading to a considerable uncertainty in the parameters of the probabilistic distributions describing rainfall depth...

This study involves the design and development of a triangular solar still (TSS) for providing pure water from saline and contaminated water. The TSS was fabricated with cheap, lightweight and locally acquired but durable materials for easy maintenance. The TSS consists of a trough made of Perspex, main frame, polythene cover and support structure....

Malaysia is a tropical country with high rainfall rate. But there is increasing demand on water due to development. Also, global weather change makes the dry season longer and evaporation rate from impounding reservoirs higher. So, evaporation as a natural phenomenon contributes in reducing the availability of water for various uses. Estimation of...

One of the most important waterway components is vegetation, which play a pivotal role in the flow and sediment transport. Vegetation environment and characteristics, including vegetation porosity or density, shape, flexibility and vegetation height, are significantly affected in vegetated channels. Various vegetation positions and arrangements suc...

In this research, attempts are maid to evaluate the performance of HEC-HMS (Hydrological modeling) in simulating the rainfall-runoff using two different rainfall infiltration methods. The rainfall-runoff process for the study area which consist of two catchments namely kenyir catchment and Berang catchment, Terengganu, Malaysia is simulated using H...

Estimation of flood in basins with poor condition of hydrometric stations as in quantity and quality is a dominant problem around the world, mainly in developing country where lack of funds and human resources cause more limitation in number of gauging stations. One of the areas that experience frequent floods and also suffer from small number of s...

This paper investigates evaporation at Algardabiya Reservoir, Sirte, Libya. Evaporation from Algardabiya Reservoir is the main problem faced which contributes in water loss. Libya is considered as arid region with limited water resources. Modeling of evaporation from the reservoir is crucial for water management at the area. Three evaporation model...

Solar water distillation might be one of the viable options for providing drinking water for a single house or a small community in an arid, remote or coastal region. A new type of solar distillation called a Tubular Solar Still (TSS) was designed to overcome some disadvantages in the maintenance and management of a basin type still. A production m...

The results of an experimental study on clear-water scour at pile groups under steady flows at threshold velocity are presented. A wide range of pile group arrangements, spacing, and submergence ratios are studied. Uniform bed material in a 46-m long, 1.52-m wide, and 1.9-m deep flume was used to obtain comprehensive data. Empirical relations to de...

Penurasan merupakan unit operasi utama bagi loji olahan air. Media penuras yang lazim digunakan adalah berbentuk butiran seperti pasir, antrasit, arang, magnetik, garnit dan tempurung kelapa. Prestasi penuras media berbentuk butiran telah terbukti berkesan. Walau bagaimanapun, keperluan media penuras alternatif yang kos efektif masih diperlukan mem...

2012): Effect of the packaging and storage conditions on the coagulation activity of spray-dried salt-extracted Moringa oleifera , Desalination and Water Treatment, Moringa oleifera is one of the natural coagulants considered as an alternative to synthetic coagulants. Several studies were carried out on the usage and extraction of this natural coag...

2012): Effect of the packaging and storage conditions on the coagulation activity of spray-dried salt-extracted Moringa oleifera , Desalination and Water Treatment, Moringa oleifera is one of the natural coagulants considered as an alternative to synthetic coagulants. Several studies were carried out on the usage and extraction of this natural coag...

Effect of the packaging and storage conditions on the coagulation activity of spray-dried salt-extracted Moringa oleifera , Desalination and Water Treatment, Moringa oleifera is one of the natural coagulants considered as an alternative to synthetic coagulants. Several studies were carried out on the usage and extraction of this natural coag-ulant....

A study on the effectiveness of salt extracted Moringa oleifera seeds as a coagulant for turbid-ity removal in water treatment process under different operational parameters (configura-tions) of spray drying, storage, and packaging conditions is presented. The operational parameters were inlet temperature, outlet temperature, and pumping rates. The...

Social and economic detriments are the most important consequences of a bridge failure. Stability problems of such structures against failure and the depth of the abutments are directly related to the amount of the adjusted scour. Economy, reliability, and stability have been main concerns regarding designing abutment bridges enhanced preventing sc...

Estimation of evaporation from three models namely: Penman, Priestley–Taylor, and Linacre for calculating evaporation rate were compared with the observed values of data collected from pan evaporimeter. Based on two years data, the most promising and reliable model for Algardabiya reservoir in Libya has been established. Various statistical measure...

Observed rainfall is used for runoff modeling in flood forecasting where possible, however in cases where the response time of the watershed is too short for flood warning activities, a deterministic quantitative precipitation forecast (QPF) can be used. This is based on a limited-area meteorological model and can provide a forecasting horizon in t...

Land-use change has significant impacts on hydrologic processes at the watershed level. In this study, hydrologic models and spatial data were used to assess the effects of land-use changes and predict the effects of two future land-use scenarios on the flood regime of the Damansara Watershed. Due to urban growth, the Damansara Watershed has seen i...

Malaysia is a tropical country and it is subjected to flooding in both the urban and rural areas. Flood modelling can help to reduce the impacts of flood hazard by taking extra precautions. HEC-RAS model was used to predict the flood levels at selected reach of the Langat River with a total length of 34.4 km. The Langat River is located in the stat...

non-commercial research and educational use only. Not for reproduction or distribution or commercial use. This article was originally published by IWA Publishing. IWA Publishing recognizes the retention of the right by the author(s) to photocopy or make single electronic copies of the paper for their own personal use, including for their own classr...

The outcomes of an experimental study on local scour at a pile cap are presented. Experiments were conducted with the approaching flow having an undisturbed flow depth and a threshold flow velocity. The main variables investigated were pile cap dimensions and location relative to the streambed. According to the rate of change in scour depth, the sc...

In this study, the Linacre evaporation model was tested for its accuracy using daily, weekly and monthly records. The records were collected from class A evaporation pan installed at Algardabiya Reservoir, Sirt, Libya. The records for three years were used to calibrate and validate the model. Statistical tests show that the model gives a reasonable...

This paper describes a comparison between our first model of a Tubular Solar Still (TSS) and a second one. The first model was designed by our research group using a vinyl chloride sheet as a transparent tubular cover. Since then, we have designed the second model that has improved the assembly, economy and maintenance over the first model. In the...

A new sub-surface detention/retention system, called the Storage–Infiltration Block (SIB) system, has been developed for the purposes of reduction of volume and flow rate of stormwater runoff and recharging groundwater. This paper presents a method in the determination of the maximum storage volume and maximum surface area required for the system....

Disposal of sewage sludge is a main problem faced by local municipalities in Malaysia. Sludge conditioned with chemical polymer often termed as undesirable use for land application. However, using natural polymer will help to reduce the impact of this problem. In this study, optimization using Moringa oleifera seeds as a natural polymer in sewage s...

The efficiency of advanced oxidation processes (AOPs), enzymatic treatment and combined enzymatic/AOP sequences for the colour remediation of soda and chemimechanical pulp and paper mill effluent was investigated. The results indicated that under all circumstances, the AOP using ultraviolet irradiation (photo-Fenton) was more efficient in the degra...

Proper integrated management of a dam reservoir requires that all components of the water resource system be known. One of these components is the daily reservoir inflow which is the subject matter of this study, i.e. to establish predictions of what is coming in the next rainfall-runoff process over a catchment. The transformation of rainfall into...

The study was to evaluate SWAT model for flow simulation and forecasting in the Upper Bernam humid tropical river basin, which is the main source of irrigation water supply for a rice granary. Land use in the study area has rapidly changed from the year of 1984 until today. The study was conducted using 27 years of records (1981–2007). Calibration...

This research investigated the efficiency of Advanced Oxidation Processes, Enzymatic treatment, and combined enzymatic/AOPs sequences on color remediation of CMP pulp and paper mills effluent. Regarding enzymatic treatment two kinds of fungal enzymes; Laccase (EC: 1.10.3.2) from Terametes Versicolor and Versatile Peroxidase (EC: 1.11.1.7) from Bjer...

The effect of different form of dosing using Moringa oleifera seeds in sewage sludge conditioning was studied. Settled activated sludge after clarification process was obtained from sludge holding tank in Sewage Treatment Plant, Taman Tun Dr. Ismail, Kuala Lumpur, Malaysia. In this study, sludge conditioning with Moringa oleifera seeds in 3 differe...

A new matrix approach which incorporated Rajagopalan and Tien model was developed to simulate the progress of sediment deposition in sublayers of fi ltration media for mono-media sand and BOPS fi lters as well as dual-media BOPS-sand fi lters, at different time until the end of fi ltration process. The results of specifi c deposit in the matrix for...

This study focuses on a technique to improve runoff modeling based on radar- derived rainfall and hydrological model for the whole watershed. GIS tools were used to provide the model parameters for the Upper Bernam River Basin (1090 km2), Malaysia. Virtual rainfall stations are created throughout the UBRB watershed. The rainfall data for these stat...

These studies are mainly focused on effective depth, initial head loss and backwashing criteria that have been identified as the key factors in relation to the fundamental parameters and also, indicated possible operation performance. Granular filter media used in this study are limited to burned oil palm shell (BOPS) and sand. The study on the bed...

Peak runoff from a catchment is influenced by many factors such as intensity and duration of rainfall, catchment topography, catchment shape, land use and other variables. For a particular catchment, landuse change and other human activities will alter the characteristic of catchment hydrograph. Problem statement: As a result of urbanization, the m...