Hydrology
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Item Restricted A Comparative Review on Malaysia's Water Quality Index Model with International Water Quality Index Models for Surface Water Quality Classification(IOP Publishing, 2023) Y Q Liang; E L Yong; K V Annammala; K Bidin; A Nainar; L S Mazilamani; N A MohamadThis paper aims at comparing the advantages and the limitations across several different types of WQI models (CCMEWQI, NSFWQI, IWQI, WQI Malaysia), in order to provide suggestions to improve the accuracy and sensitivity of the WQI models. IWQI and CCMEWQI are fully unbiased due to no weightage, however, statistical technique is recommended to be included in parameter selection step to increase its accuracy.Item Restricted Analysis of rainfall events over Peninsular Malaysia(Wiley, 2016) Ren Jie Chin; Sai Hin Lai; Kian Boon Chang; Faridah Othman; Wan Zurina Wan JaafarIn this study the data collected by 16 automatic rainfall stations distributed uniformly across Peninsular Malaysia are analysed using a Rainfall Event Mining Tool (RainEMT) developed by the authors in Microsoft Access, using Visual Basic for Applications. RainEMT allows the easy extraction of large-scale rainfall event data such as the total number of yearly or monthly rainfall events, annual maximum rainfall or annual maxima series, and event total rainfall, with threshold selection from a large time series rainfall dataset. The rainfall events are separated by a user-defined minimum inter-event time (MIT).Item Restricted Annual water balance and seasonality of evapotranspiration in a Bornean tropical rainforest(Elsevier, 2005) Tomo omi Kumagai; Taku M. Saitoh; Yoshinobu Sato; Hiroshi Takahashi; Odair J. Manfroi; Toshiyuki Morooka; Koichiro Kuraji; Masakazu Suzuki; Tetsuzo Yasunari; Hikaru KomatsuThis study presents the results of 2 years combined field measurements of water vapor exchange with the atmosphere and simplified model calculations at Lambir Hills National Park, Sarawak, Malaysia (4 12'N, 114 02'E). The study site was located in a lowland mixed dipterocarp forest, a major type of Bornean tropical rainforest, where there is no clear seasonality in environmental factors such as radiation, temperature, vapor pressure deficits and precipitation; instead, unpredictable dry spells often occur throughout the year.Item Restricted Changes in reference evapotranspiration and its driving factors in peninsular Malaysia(Elsevier, 2020) Sahar Hadi Pour; Ahmad Khairi Abd Wahab; Shamsuddin Shahid; Zulhilmi Bin IsmailTrends in reference evapotranspiration (ETo) have been found highly diverse in different regions of the globe due to the contradictory changes in the meteorological variables that define ETo. Despite a significant impact of ETo in water resources and ecology, knowledge on the changes and the cause of the changes in ETo is very limited in tropical regions. The trends in ETo, the factors influencing the changes in ETo and the change point (year) that made the trend significant were evaluated in this study for tropical peninsular Malaysia.Item Open Access Characteristics of short-duration extreme rainfalls in Selangor, Malaysia(Wiley, 2006) M. N. Desa; P. R. RakhechaA short-duration rainfall analysis for Kuala Lumpur and part of the Malaysian state of Selangor was made by Desa (1997) but a detailed analysis is still lacking for other raingauges in the state. Here we analyse historical rainfall records from rain gauges from the whole of Selangor, located in the equatorial region so as to provide information on short-duration extreme rainfalls and to estimate their frequency of occurrence.Item Restricted Chemical characteristics of rainwater in the tropical rainforest region in northwestern Borneo(Springer, 2020) Ninu Krishnan Modon Valappil; Prasanna Mohan Viswanathan; Vijith HamzaA comprehensive study of the chemical composition of rainwater was carried out from October 2016 to September 2017 in the equatorial tropical rainforest region of northwestern Borneo. Monthly cumulative rainwater samples were collected from different locations in the Limbang River Basin (LRB) and were later categorized into seasonal samples representing northeast monsoon (NEM), southwest monsoon (SWM), and inter-monsoon (IM) periods.Item Restricted Choosing the best fit probability distribution in rainfall design analysis for Pulau Pinang, Malaysia(Springer, 2023) Rofat Bunmi Mudashiru; Ismail Abustan; Nuridah Sabtu; Hanizan B. Mukhtar; Waheed BalogunDesign rainfall is frequently utilized in the planning and design of urban infrastructure, including culverts and urban drainage systems. The choice of an appropriate probability distribution that sufficiently fits the observed rainfall data is one of the key elements in designing rainfall estimation. The current study compared five probability distribution methods which include Gumbel, log-Normal, Normal, Pearson III, and log-Pearson III probability distribution method (PDMs) to analyze the rainfall pattern of the study area.Item Restricted Climate extremes in Malaysia and the equatorial South China Sea(Elsevier, 2011) Ahmed Salahuddin; Scott CurtisThe southern extent of the South China Sea (SCS) is an important natural resource epicenter for Malaysia which experiences climate extremes. This paper documents the variability of extremes in the equatorial SCS through selected ground-based observations of precipitation in Malaysia and ship-based observations of wind data in the Maritime Continent region, to elucidate the interrelationship between precipitation variability over Malaysia and wind variability over the ocean.Item Open Access Comparison Between Activated Carbon and Sand Filtration Method for Water Quality Enhancement: A Case Study(IOP Publishing, 2021) M R A A Chan; N Kasmuri; R Ahmad; R Santiagoo; S RamasamyThis study aims to determine the water quality status of Metropolitan Lake, Kuala Lumpur before and after the treatment of activated carbon and sand filtration method. Here, physical and chemical characteristics were conducted for in-situ and laboratory analysis. Temperature, pH, dissolved oxygen (DO), total dissolved solids (TDS) and turbidity of water samples were taken in-situ. Meanwhile, parameters of biochemical oxygen demand (BOD), chemical oxygen demand (COD), turbidity, total suspended solids (TSS), ammonia nitrogen (NH3-N) were determined in the laboratory.Item Restricted Comparison of GPM IMERG, TMPA 3B42 and PERSIANN-CDR satellite precipitation products over Malaysia(Elsevier, 2018) Mou Leong Tan; Harrif SantoThe launch of the Global Precipitation Measurement (GPM) mission has prompted the assessment of the newly released satellite precipitation products (SPPs) in different parts of the world. This study performed an initial comparison of three GPM IMERG products (IMERG_E, IMERG_L and IMERG_F) with its predecessor, the TMPA 3B42 and 3B42RT products, and a long-term PERSIANN-CDR product over Malaysia. The performance of six SPPs was evaluated using 501 precipitation gauges from 12 March 2014 to 29 February 2016.Item Open Access Comparison of rainwater quality before and during the MCO using chemometric analyses(Springer, 2023) Nadiana Arifn; Hafzan Juahir; Roslan Umar; Mokhairi Makhtar; Nur Hanis Mohamad Hanapi; Azimah Ismail; Munirah Abdul ZaliThis study aimed to classify the spatiotemporal analysis of rainwater quality before and during the Movement Control Order (MCO) implementation due to the COVID-19 pandemic. Chemometric analysis was carried out on rainwater samples collected from 24-gauge stations throughout Malaysia to determine the samples' chemical content, pH, and conductivity.Item Restricted Correcting bias of satellite rainfall data using physical empirical model(Elsevier, 2021) Ghaith Falah Ziarh; Shamsuddin Shahid; Tarmizi Bin Ismail; Md Asaduzzaman; Ashraf DewanThe provision of high resolution near real-time rainfall data has made satellite rainfall products very potential for monitoring hydrological hazards. However, a major challenge in their direct-use can be problematic due to measurement error. In this study, an attempt was made to correct the bias of Global Satellite Mapping of Precipitation near-real-time (GSMaP_NRT) product. Physical factors, including topography, season, windspeed and cloud types were accounted for correcting bias. Peninsular Malaysia was used as the case study area. Gridded rainfall, developed from 80 gauges for the period 2000-2018, was used along with physical factors in a two-stage procedure.Item Embargo Data Banjir KL 2003-2015(Fakulti Kejuruteraan dan Alam Bina (FKAB), 2003)Data banjir yang diambil daripada beberapa kawasan di Kuala Lumpur bermula dari tahun 2003 hingga 2015. Ukuran diambil berdasarkan tempoh (duration), keamatan (intensity) dan kedalaman banjir (flood depth).Item Embargo Data Eksperimen - Spillway(Fakulti Kejuruteraan dan Alam Bina (FKAB))Data berkaitan alur tumpahan yang diukur berdasarkan flow condition, water pressure, water level, velocity, scouring potential dan flood potential based on water depth.Item Embargo Data Sedimen Tasik Kejuruteraan UKM(Fakulti Kejuruteraan dan Alam Bina (FKAB))Data diambil kira berdasarkan BR, AR, VAR dan TSSItem Open Access Disaggregation of daily rainfall data using Bartlett Lewis Rectangular Pulse model: a case study in central Peninsular Malaysia(Springer, 2014) Zulkifli Yusop; Harisaweni Nasir; Fadhilah YusofShort duration rainfall data are required for certain hydrological risk assessments. However, short timescale rainfall intensity records are still scarce due to the high cost and low reliability of the monitoring systems. One way to solve this problem is by disaggregating rainfall data using stochastic methods. This study used the Bartlett Lewis Rectangular Pulse model to disaggregate daily rainfall into hourly rainfall for ten stations in the central region of Peninsular Malaysia.Item Restricted Drought analysis and water resource availability using standardised precipitation evapotranspiration index(Elsevier, 2018) Foo Hui-Mean; Zulkifli Yusop; Fadhilah YusofTrend analysis for potential evapotranspiration (PET) and climatic water balance (CWB) is critical in identifying the wetness or dryness episodes with respect to the water surplus or deficit. The PET is computed based on the monthly average temperature for the entire Peninsular Malaysia using Thornthwaite parameterization. The trends and slope's magnitude for the PET and CWB were then investigated using Mann-Kendall, Spearman's rho tests and Thiel-Sen estimator. The 1-, 3-, 6- and 12-month standardised precipitation evapotranspiration index (SPEI) is applied to determine the drought episodes and the average recurrence interval are calculated based on the SPEI.Item Restricted Dynamics of short rainfall storms in a small scale urban area in Coly Limper, Malaysia(Elsevier, 1997) M.N.M. Desa; J. NiemczynowiczShort term storm rainfalls are recorded with a dense network of fine resolution rain gauges well distributed in a small urban catchment in Kuala Lumpur, Malaysia. The period of data collection covers the south-west monsoon (July-September), inter monsoon (October) and partly the north-east monsoon (November-December) seasons. This paper presents some findings with reference to the dynamic properties of short rainfall storms using the method of vector analysis and farther correlation analysis.Item Open Access Enhancement of Water Quality using Natural Coagulant in Shah Alam Lakes, Malaysia(IOP Publishing, 2021) R A Hassan; N Kasmuri; R Ahmad; R Santiagoo; S RamasamyThis research aims to investigate the optimum condition of natural coagulant (Moringa oleifera) for the treatment of surface water from Shah Alam Lakes in Selangor Region, Malaysia. These lakes can be a potential source of water if water shortage occurs. At first, the characteristics of the water samples were determined. Later, the sample of surface water from the lakes was examined with the jar test for the coagulation-flocculation process using Moringa oleifera with different concentrations. The water quality parameterssuch as pH, turbidity, suspended solids, phosphorus and chemical oxygen demand were evaluated.Item Open Access Erosion and Sedimentation at Headwater Stream: A Case Study for Pergau Water Intake(IOP Publishing, 2020) Mohd Sofiyan Sulaiman; Mohamad Faiz Mohd Amin; Abdul Hafidz Yusoff; Mohd Fikri Samsudin; Aisah Md ShukorDue to strategic location for water intake facilities, a study was carried out to determine the extent of erosion and sedimentation process at Pergau water intakes that conveyed water into Pergau Lake. Three specific aims were formulated: Soil loss determination at catchment scale, sediment load determination at reach scale and river bank stability and toe erosion near the intake facility. A desktop study using remote sensing and GIS tools was executed to determine the extent of soil loss at catchment scale. The sediment load and river bank stability were measured in the field using wading technique.