Wan Ruslan Ismail - Academia.edu (original) (raw)

Papers by Wan Ruslan Ismail

Water, 2021

High resolution models from the High-Resolution Model Intercomparison Project (HighResMIP), part ... more High resolution models from the High-Resolution Model Intercomparison Project (HighResMIP), part of CMIP6, have the capacity to allow a better representation of the climate system in tropical regions, but how different model resolutions affect hydrological outputs remains unclear. This research aims to evaluate projections of hydro-climatic change of the Johor River Basin (JRB) in southern Peninsular Malaysia between 1985 to 2015 and 2021 to 2050, focusing on uncertainty quantification of hydrological outputs from low (>1°), medium (0.5° to 1°) and high (≤0.5°) horizontal resolution models. These projections show future increases in annual precipitation of 0.4 to 3.1%, minimum and maximum temperature increases of 0.8 to 0.9 °C and 0.9 to 1.1 °C, respectively. These projected climate changes lead to increases in annual mean streamflow of 0.9% to 7.0% and surface runoff of 7.0% to 20.6% in the JRB. These annual mean changes are consistent with those during the wet period (November ...

Developmental pressure is encroaching many small towns and cities in Malaysia. The wave of develo... more Developmental pressure is encroaching many small towns and cities in Malaysia. The wave of development has caused small towns like Sungai Petani Town and its surrounding catchment area to be affected by the changing land uses due to developmental pressure in the catchment area. This paper examined the temporal patterns of nutrient concentrations longitudinally along the Sungai Petani River from March 2012 to December 2013 due to the unequal distribution of ‘green’ areas with respect to the ‘grey’ areas. Four stations were chosen longitudinally from upper Sungai Petani River downstream towards Sungai Petani Town and were monitored from upstream part of Sungai Petani Town which is the least affected station, through Sungai Petani Town and towards the downstream station below the Sungai Petani Town. Water sampling at all stations were performed through grab sampling technique at depths of about 0.5 m. Water samples were analysed only for dissolved forms of nitrate (NO3), ammoniacal nit...

Proceedings of the International Association of Hydrological Sciences, 2015

The Kinta River, draining an area of 2566 km 2 , originates in the Korbu Mountain in Perak, Malay... more The Kinta River, draining an area of 2566 km 2 , originates in the Korbu Mountain in Perak, Malaysia, and flows through heterogeneous, mixed land uses ranging from extensive forests to mining, rubber and oil palm plantations, and urban development. A land use change analysis of the Kinta River catchment was carried out together with assessment of the long-term trend in rainfall and sediment fluxes. The Mann-Kendall test was used to examine and assess the long-term trends in rainfall and its relationship with the sediment discharge trend. The land use analysis shows that forests, water bodies and mining land declined whilst built and agricultural land use increased significantly. This has influenced the sediment flux of the catchment. However, most of the rainfall stations and river gauging stations are experiencing an increasing trends, except at Kinta river at Tg. Rambutan. Sediment flux shows a net erosion for the period from 1961 to 1969. The total annual sediment discharge in the Kinta River catchment was low with an average rate of 1,757 t/km 2 /year. From 1970 to 1985, the annual sediment yield rose to an average rate of 4062 t/km 2 /year. Afterwards, from 1986 to 1993, the total annual sediment discharge decreased to an average rate of 1,306 t/km 2 /year and increased back during the period 1994 to 2000 to 2109 t/km 2 /year. From 2001 to 2006 the average sediment flux rate declined to 865 t/km 2 /year. The decline was almost 80% from the 1970s. High sediment flux in the early 1970s is partly associated with reduced tin mining activities in the area. This decreasing trend in sediment delivery leaving the Kinta River catchment is expected to continue dropping in the future.

Natural Hazards and Earth System Sciences Discussions, 2014

The Weather Research Forecast (WRF) model includes various configuration options related to physi... more The Weather Research Forecast (WRF) model includes various configuration options related to physics parameters, which can affect the performance of the model. In this study, different numerical experiments were conducted to determine the best combination of physics parameterization schemes for the simulation of sea surface temperatures, latent heat flux, sensible heat flux, precipitation rate, and wind speed that characterized typhoons. Through these experiments, several physics parameterization options within the WRF model were exhaustively tested for typhoon Noul, which had originated in the South China Sea in November 2008. The model domain consisted of one coarse domain and one nested domain. The resolution of the coarse domain was 30 km, and that of the nested domain was 10 km. In this study, model simulation results were compared with the Climate Forecast System Reanalysis (CFSR) data set. Comparisons between predicted and control data were made through the use of standard statistical measurements. The results facilitated the determination of the best combination of options suitable for predicting each physics parameter. Then, the suggested best combinations were examined for seven other typhoons and the solutions were confirmed. Finally, the best combination was compared with other introduced combinations for wind speed prediction for typhoon Washi (2011). The contribution of this study is to have attention to the heat fluxes besides the other parameters. The outcomes showed that the suggested combinations are comparable with the ones in the literature.

IAHS …, 2002

Studies on nutrient transport in rivers is still in its infancy in Malaysia. This study investiga... more Studies on nutrient transport in rivers is still in its infancy in Malaysia. This study investigates the effects of different land-use activities on the transport of nutrients and sediments into the Timah Tasoh Reservoir, northern Malaysia, during the low flood periods (January-June 2001). Nutrient retention and sedimentation were observed in the littoral zone of the reservoir resulting in suspended sediment concentrations (TSS) and nutrients being almost one third lower in the main body of the reservoir compared to the incoming sources. Nitrate concentrations were also reduced by 20%. Mean sedimentation rates in the reservoir were 300 mg day-1 , ranging from 120 mg day-1 in the middle of the reservoir to a maximum of 800 mg day-1 near the littoral zones.

MATEC Web of Conferences, 2016

Bukit Merah Reservoir (BMR) is the oldest reservoir in Malaysia constructed to supply irrigation ... more Bukit Merah Reservoir (BMR) is the oldest reservoir in Malaysia constructed to supply irrigation water to the Kerian Irrigation Scheme. Depletion of storage capacity due to sedimentation process is the most concerning issue of the reservoir recently. Sediment analysis is also very important when monitoring the substances that appear in the reservoir water. Environmental toxins, like heavy metals and hydrophobic organic components, as well as nutrients such as nitrogen and phosphorus are readily bond to the particulate matter. Factors in the reservoir that affect the particulate matter will aid the distribution of contaminants in the sediments. The contaminants in the sediments could have higher concentrations compared to those found in the overlying water. This means that the sediment plays an important role in the cycling of nutrients and distribution of contaminants in the ecosystem. The objectives of this research are to determine the relationship of nutrient and heavy metal content for sediment and overlying water. Nutrient profile information is provided from sediment sample analysis. Based on the data from the horizontal distribution of surface sediment phosphorus in BMR, it was apparent that the highest concentration occurred in the reservoir inlet from Sungai Kurau catchment area. Phosphorus and nitrogen in BMR have a similar trend of decreasing concentration from upstream to downstream. The phosphorus and nitrogen concentrations of surface sediment were in fact significantly correlated with phosphorus and nitrogen concentrations of surface water because of the high value of determination of correlation (R 2). As a conclusion, the deposition of sediments was found to bring along external nutrients. Variability of phosphorus and nitrogen concentrations in the sediment directly affects the quality of water which is very important for irrigation and domestic uses.

Water Science, 2023

To acquire baseline data for a remote Pergau Hydroelectric Power Plant reservoir, a hydrological ... more To acquire baseline data for a remote Pergau Hydroelectric Power Plant reservoir, a hydrological and water quality examination of feeder rivers and reservoir water was conducted in 2013. The water balance of the reservoir was determined, and gauging and sampling were carried out in dry and wet periods. Dilution gauging was used to estimate the feeder river discharge. The total water flow into the reservoir increases nearly fivefold between the dry and wet seasons, while river discharge increases two to fivefold. All of the river intakes had Class 1 NWQS water quality. The lake's water quality was Class 1 up to the top 3 meters, but below that, at some places, the water quality deteriorated to Class II. In the dry season, the trophic status of Pergau Reservoir is eutrophic as measured by TP (59.21) and chlorophyll-a (52.36) and the TSI (SD) was 53.93 Eutrophication occurrences will cause serious limitations in water use applicability. This research contributes to the biogeographical and limnological understanding of the Pergau catchment, as well as laying the groundwork for more sophisticated hydro-ecological investigations. Anthropogenic activities, together with runoff from agricultural operations and the presence of algae, are some of the sources of contamination noted in the study. Stricter legislation, stricter enforcement of current standards, matching of non-technical and technosocial remedial actions, and education are among the recommendations made for the Pergau Reservoir's protection.

SPIE Proceedings, 2003

The feasibility of using digital camera imagery for estimating the concentration of total suspend... more The feasibility of using digital camera imagery for estimating the concentration of total suspended sediments (TSS) in the Timah Tasoh reservoir was investigated. Digital images were captured from a low-altitude light aircraft. Three selected images were mosaiced to produce bigger image of the study area. Atmospheric corrections and mosaic sincronourization were performed by using the average digital number of grass

Japan Geoscience Union, 2015

Wadi Siham Basin (WSB) is one of the most important agricultural areas, and one of the seven larg... more Wadi Siham Basin (WSB) is one of the most important agricultural areas, and one of the seven largest wadis in the western region of the Republic of Yemen. This study aims to evaluate the quantity and spatial and temporal variation of rainfall and runoff. The rainfall (1979-2008) as well as runoff and floods (1990-2009) data were collected and treated statistically in order to evaluate the rainfall and runoff trends. The areal catchment rainfall was estimated by using the Thiessen polygon method, while the recurrence interval and probability analysis were carried out using the Hazen method. The Mann?Kendall and Sen’s slope analyses results showed that the Wallan and Al-Amir stations produced significant negative values (-4.72 and -6.11 mm/year respectively). However, the rainfall trend in Dhamar had a significant positive value of 50.20 mm/year. The average annual rainfall in WSB was 346.39 mm/year. The total amount of rainfall was 1711.26 Mm . The mean annual water runoff was 82.92 ...

Abstrak 'Kesihatan' sesebuah lembangan saliran akan dicerminkan oleh kualiti air yang bai... more Abstrak 'Kesihatan' sesebuah lembangan saliran akan dicerminkan oleh kualiti air yang baik. Warna dan kekeruhan air adalah salah satu parameter yang mencerminkan sesuatu kualiti air dan ia berkaitan dengan kepekatan sedimen terampai yang terdapat di dalamnya. Sedimen yang terhasil daripada proses hakisan di dalam sesebuah kawasan tadahan akan memasuki anak-anak sungai dan tasik dan beban sedimen serta kekeruhan air akan menyebabkan banyak masalah kepada organisma hidup di dalam air. Pada masa kini, tanah telah menjadi salah satu sumber yang dihadkan di Pulau Pinang disebabkan oleh keadaan topografinya yang berbukit dan tanah rata yang agak terhad. Pulau Pinang merupakan sebuah bandar perindustrian yang pesat serta padat dan dalam rangka menghadapi cabaran masa depan yang disebabkan oleh kepesatan pembangunan ekonomi dan terdapat permintaan yang tinggi bagi keperluan kawasan tanah rata. Pelbagai aktiviti dan pembukaan tanah ini seterusnya memberi sumbangan terhadap kepekatan ...

Urban runoff is responsible for water quality deterioration of receiving water downstream of urba... more Urban runoff is responsible for water quality deterioration of receiving water downstream of urban areas. Lately new engineering approaches that integrate ecological consideration had been used to combat urban drainage issues such as erosion and water quality. BioEcological Drainage System (BIOECODS) is an example of integration of engineering and ecological components to solve urban runoff. BIOECODS at USM Engineering Campus in Nibong Tebal, Penang, combines three engineering techniques to manage storm water based on control at source approach by integrating the drainage components with ecological components (i.e constructed wetland, detention pond, wading stream and recreational ponds). This paper reports our findings of the water quality parameters of water bodies in the ecological components conducted from April 2003–September 2003 every fortnight water sampling strategy. Results suggested that most of the water quality parameters improved from detention pond towards recreationa...

Indian Journal of Scientific Research, 2014

Typhoons are significant events around the world, and can cause large-scale damage. This study is... more Typhoons are significant events around the world, and can cause large-scale damage. This study is an effort to dedicate the variations of typhoon activities during 1970-2011 over Asia-Pacific region. The data of typhoons through the paper were achieved from IBTrACS data set, and the data of sea surface temperature were obtained from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) data archives. Changes of typhoon characteristics were examined by analyzing the 6-hourly data during the period. The outcomes showed that the possibility of a typhoon event was highest in the area between 10-30˚N30˚N and 120-140˚E140˚E. In addition, typhoon intensity, in the case of wind speed of higher than 118 km/h, had a maximum percentage of 36.9. For minimum central pressure, the amount of 1000 to 990 mbar had the highest percentage of 25.1. Furthermore, the typhoon event had a dropping trend in the recent decade. The results also showed that the number of typhoons and the standard deviation of sea surface temperature had an inversely connection.

This study, statistically describes variations of the total heat flux during typhoons over the So... more This study, statistically describes variations of the total heat flux during typhoons over the South China Sea. Total heat flux was considered as a sum of the latent heat flux (LHF) and sensible heat flux (SHF). Typhoons in the South China Sea were selected from 1991 to 2011. These effects were examined based on archived data from the National Centers for Environmental Prediction and the National Center for Atmospheric Research (NCEP-NCAR) and the number of typhoons from the Joint Typhoon Warning Center during the indicated period. A long-term study on typhoons behavior indicated that on average, the trend of overall heat flux is related to the number of typhoons. By contrast, the results showed that the total heat flux touched its maximum amounts in July and August, and prepared the required energy for typhoon generation, so the number of typhoons enhanced during consequent months, August and September which had maximum number of typhoons during the years. Furthermore, from the spa...

Bukit Merah Reservoir (BMR) is one of the 51 impoundments in Malaysia. BMR is the oldest reservoi... more Bukit Merah Reservoir (BMR) is one of the 51 impoundments in Malaysia. BMR is the oldest reservoir built in the early 1900s originally to store water for irrigation, but nowadays its functions include also flood control and water supply. Nowadays, it is threatened by land use change in the upper catchments and surrounding activities, which feeding eroded material and chemicals into the reservoir. Suspended sediment, as well as, nutrient fluxes into BMR are becoming an increasing threat to the reservoir, as its sedimentation and eutrophication accelerate. This paper discusses our study on the BMR carried out between March 2008 and April 2009 to assess the water quality status, and to determine the sediment and Total Phosphorus (TP) influx into the south pool lake. An estimated amount of suspended sediment fluxes of about 2,900 t year-1 came from the north pool lake (18%) and 12,900 t year-1 from the main Kurau River inlet (82% of the total input to the BMR). Of these total sediment i...

Rivers and lakes are natural heritage that should be preserved at all cost. The history of human ... more Rivers and lakes are natural heritage that should be preserved at all cost. The history of human civilisation has proven the importance of rivers and lakes to humans but development activities had changed the water quality status of rivers and lakes. Due to pollution, they are no longer of any use to human beings. This study was conducted to evaluate the changes of water quality in major rivers, lakes and dams in the northern region of Peninsular Malaysia. Sampling was carried out in February 2010 and completed in April of the same year. The sampling consisted of 62 sampling stations located in rivers, lakes and dams in Perlis, Kedah and Penang. Readings were taken based on 11 hydrological and physicochemical parameters and the water quality status was classified under the Interim National Water Quality Standards (INWQS) which tabulated six levels of pollution ranging from moderate to extremely polluted in the order of I, IIA, IIB, III, IV and V. Results from the study show that mos...

Geografia: Malaysian journal of society and space, 2017

Environmental impact induced by rapid urbanization and development may be traced from changes in ... more Environmental impact induced by rapid urbanization and development may be traced from changes in local rainfall trends and variations. This study examined the trends and variations of rainfall in the Kinta River basin, Perak, a region in Malaysia that is rapidly urbanizing and developing. Long-term rainfall data from the year 1960 to 2006 were obtained from the Department of Irrigation and Drainage (DID) involving 15 rainfall stations in the Kinta River basin were employed to analyse long-term variations and precipitation trends. Results of the Mann-Kendall tests show that the Kinta River basin received high rainfall during the Northeast monsoon (950 mm) as compared to that received during the Southwest monsoon (309 mm). The tests also showed that the annual rainfall in the Kinta River basin had an increasing trend from the year 1960-2006 with the value of S=217 as did the monthly rainfall (except in the months of June and July 8) and seasonal rainfall during Northeast monsoon (S = ...

This study was based on plots under various types of land use and covers at North Pool, Bukit Mer... more This study was based on plots under various types of land use and covers at North Pool, Bukit Merah Reservoir (BMR) catchment. The rainfall was generated from a rainfall simulator to produce constant intensity of 53 mm/hour. Runoff, sediment and nutrient losses were measured. The results show that sediment concentration was highest from the bare soil plot (429.80 mg/L), and the lowest is from the grass plot (135.80 mg/L). Soil types in the catchment area also influenced the infiltration rate and the amount of surface runoff. The result also shows that the nutrient concentration in the totality of all forms of nitrogen is highest from the bare soil plot. This is due to the highest surface runoff were generated and the top layer soil was exposed to erosion activities of flowing water. The highest implication to the catchment management or soil conservation and nutrient retention has deteriorated water quality supplying to Bukit Merah reservoir. In controlling this problem, best manage...

A small drainage basin (0.5 km2) was selected on the Relau hill to evaluate sediment and nutrient... more A small drainage basin (0.5 km2) was selected on the Relau hill to evaluate sediment and nutrient export. Stream flow gauging, water depth and gulp water samples were collected manually on a weekly basis between November 2001 to October 2002 with additional gauging and water samples taken during storm events. The concentrations of sediment and nutrient were analysed to determine the quality of the river water and the health of the catchment. The highestsuspended sediment concentrations and nutrients concentration in upper Relau catchment are, in most cases, associated with periods of high discharge during the monitoring period. Hysteresis relationships between SSC, NO3-N, TN, orthophosphate and TP concentration with discharge (Q) shows some form of pattern of variation during the monitoring period. The hysteresis approach was used to identify the sources of SSC, NO3-N and orthophosphate in streams. The findings from this study are common to most drainage systems having seasonal bimo...

A study was carried of out to assess the sediment balance of a shallow Timah Tasoh Reservoir (Are... more A study was carried of out to assess the sediment balance of a shallow Timah Tasoh Reservoir (Area: 191 km2). Streamflow gauging and water sampling was carried out at three river inputs to the reservoir, and at the reservoir outlets. River water samplings were carried out every two weeks but frequent and intensive sampling during storm events. The land use in the catchment area ranging from urban area to agriculture, sugar cane, rubber, paddy, rural villages, smalltowns, quarrying and mining activities. Suspended sediment load data was used to derive the sediment balance. Jarum River (S1), Upper Pelarit River (S2) and Chuchuh River (S3) produced 10,032.3 t; 6,439.2 t; 1,061.4 t of sediment respectively while suspended sediment yield in S1, S2 and S3 were 155.8 tkm-2yr-1, 150.7 tkm-2yr-1, and 71.7 tkm-2yr-1 respectively. Storms play a major role in transporting sediment from the catchment areas. Almost 88.7% of the total suspended sediment yield is transported from S1, 56.7% from S2 ...

Water, 2021

High resolution models from the High-Resolution Model Intercomparison Project (HighResMIP), part ... more High resolution models from the High-Resolution Model Intercomparison Project (HighResMIP), part of CMIP6, have the capacity to allow a better representation of the climate system in tropical regions, but how different model resolutions affect hydrological outputs remains unclear. This research aims to evaluate projections of hydro-climatic change of the Johor River Basin (JRB) in southern Peninsular Malaysia between 1985 to 2015 and 2021 to 2050, focusing on uncertainty quantification of hydrological outputs from low (>1°), medium (0.5° to 1°) and high (≤0.5°) horizontal resolution models. These projections show future increases in annual precipitation of 0.4 to 3.1%, minimum and maximum temperature increases of 0.8 to 0.9 °C and 0.9 to 1.1 °C, respectively. These projected climate changes lead to increases in annual mean streamflow of 0.9% to 7.0% and surface runoff of 7.0% to 20.6% in the JRB. These annual mean changes are consistent with those during the wet period (November ...

Developmental pressure is encroaching many small towns and cities in Malaysia. The wave of develo... more Developmental pressure is encroaching many small towns and cities in Malaysia. The wave of development has caused small towns like Sungai Petani Town and its surrounding catchment area to be affected by the changing land uses due to developmental pressure in the catchment area. This paper examined the temporal patterns of nutrient concentrations longitudinally along the Sungai Petani River from March 2012 to December 2013 due to the unequal distribution of ‘green’ areas with respect to the ‘grey’ areas. Four stations were chosen longitudinally from upper Sungai Petani River downstream towards Sungai Petani Town and were monitored from upstream part of Sungai Petani Town which is the least affected station, through Sungai Petani Town and towards the downstream station below the Sungai Petani Town. Water sampling at all stations were performed through grab sampling technique at depths of about 0.5 m. Water samples were analysed only for dissolved forms of nitrate (NO3), ammoniacal nit...

Proceedings of the International Association of Hydrological Sciences, 2015

The Kinta River, draining an area of 2566 km 2 , originates in the Korbu Mountain in Perak, Malay... more The Kinta River, draining an area of 2566 km 2 , originates in the Korbu Mountain in Perak, Malaysia, and flows through heterogeneous, mixed land uses ranging from extensive forests to mining, rubber and oil palm plantations, and urban development. A land use change analysis of the Kinta River catchment was carried out together with assessment of the long-term trend in rainfall and sediment fluxes. The Mann-Kendall test was used to examine and assess the long-term trends in rainfall and its relationship with the sediment discharge trend. The land use analysis shows that forests, water bodies and mining land declined whilst built and agricultural land use increased significantly. This has influenced the sediment flux of the catchment. However, most of the rainfall stations and river gauging stations are experiencing an increasing trends, except at Kinta river at Tg. Rambutan. Sediment flux shows a net erosion for the period from 1961 to 1969. The total annual sediment discharge in the Kinta River catchment was low with an average rate of 1,757 t/km 2 /year. From 1970 to 1985, the annual sediment yield rose to an average rate of 4062 t/km 2 /year. Afterwards, from 1986 to 1993, the total annual sediment discharge decreased to an average rate of 1,306 t/km 2 /year and increased back during the period 1994 to 2000 to 2109 t/km 2 /year. From 2001 to 2006 the average sediment flux rate declined to 865 t/km 2 /year. The decline was almost 80% from the 1970s. High sediment flux in the early 1970s is partly associated with reduced tin mining activities in the area. This decreasing trend in sediment delivery leaving the Kinta River catchment is expected to continue dropping in the future.

Natural Hazards and Earth System Sciences Discussions, 2014

The Weather Research Forecast (WRF) model includes various configuration options related to physi... more The Weather Research Forecast (WRF) model includes various configuration options related to physics parameters, which can affect the performance of the model. In this study, different numerical experiments were conducted to determine the best combination of physics parameterization schemes for the simulation of sea surface temperatures, latent heat flux, sensible heat flux, precipitation rate, and wind speed that characterized typhoons. Through these experiments, several physics parameterization options within the WRF model were exhaustively tested for typhoon Noul, which had originated in the South China Sea in November 2008. The model domain consisted of one coarse domain and one nested domain. The resolution of the coarse domain was 30 km, and that of the nested domain was 10 km. In this study, model simulation results were compared with the Climate Forecast System Reanalysis (CFSR) data set. Comparisons between predicted and control data were made through the use of standard statistical measurements. The results facilitated the determination of the best combination of options suitable for predicting each physics parameter. Then, the suggested best combinations were examined for seven other typhoons and the solutions were confirmed. Finally, the best combination was compared with other introduced combinations for wind speed prediction for typhoon Washi (2011). The contribution of this study is to have attention to the heat fluxes besides the other parameters. The outcomes showed that the suggested combinations are comparable with the ones in the literature.

IAHS …, 2002

Studies on nutrient transport in rivers is still in its infancy in Malaysia. This study investiga... more Studies on nutrient transport in rivers is still in its infancy in Malaysia. This study investigates the effects of different land-use activities on the transport of nutrients and sediments into the Timah Tasoh Reservoir, northern Malaysia, during the low flood periods (January-June 2001). Nutrient retention and sedimentation were observed in the littoral zone of the reservoir resulting in suspended sediment concentrations (TSS) and nutrients being almost one third lower in the main body of the reservoir compared to the incoming sources. Nitrate concentrations were also reduced by 20%. Mean sedimentation rates in the reservoir were 300 mg day-1 , ranging from 120 mg day-1 in the middle of the reservoir to a maximum of 800 mg day-1 near the littoral zones.

MATEC Web of Conferences, 2016

Bukit Merah Reservoir (BMR) is the oldest reservoir in Malaysia constructed to supply irrigation ... more Bukit Merah Reservoir (BMR) is the oldest reservoir in Malaysia constructed to supply irrigation water to the Kerian Irrigation Scheme. Depletion of storage capacity due to sedimentation process is the most concerning issue of the reservoir recently. Sediment analysis is also very important when monitoring the substances that appear in the reservoir water. Environmental toxins, like heavy metals and hydrophobic organic components, as well as nutrients such as nitrogen and phosphorus are readily bond to the particulate matter. Factors in the reservoir that affect the particulate matter will aid the distribution of contaminants in the sediments. The contaminants in the sediments could have higher concentrations compared to those found in the overlying water. This means that the sediment plays an important role in the cycling of nutrients and distribution of contaminants in the ecosystem. The objectives of this research are to determine the relationship of nutrient and heavy metal content for sediment and overlying water. Nutrient profile information is provided from sediment sample analysis. Based on the data from the horizontal distribution of surface sediment phosphorus in BMR, it was apparent that the highest concentration occurred in the reservoir inlet from Sungai Kurau catchment area. Phosphorus and nitrogen in BMR have a similar trend of decreasing concentration from upstream to downstream. The phosphorus and nitrogen concentrations of surface sediment were in fact significantly correlated with phosphorus and nitrogen concentrations of surface water because of the high value of determination of correlation (R 2). As a conclusion, the deposition of sediments was found to bring along external nutrients. Variability of phosphorus and nitrogen concentrations in the sediment directly affects the quality of water which is very important for irrigation and domestic uses.

Water Science, 2023

To acquire baseline data for a remote Pergau Hydroelectric Power Plant reservoir, a hydrological ... more To acquire baseline data for a remote Pergau Hydroelectric Power Plant reservoir, a hydrological and water quality examination of feeder rivers and reservoir water was conducted in 2013. The water balance of the reservoir was determined, and gauging and sampling were carried out in dry and wet periods. Dilution gauging was used to estimate the feeder river discharge. The total water flow into the reservoir increases nearly fivefold between the dry and wet seasons, while river discharge increases two to fivefold. All of the river intakes had Class 1 NWQS water quality. The lake's water quality was Class 1 up to the top 3 meters, but below that, at some places, the water quality deteriorated to Class II. In the dry season, the trophic status of Pergau Reservoir is eutrophic as measured by TP (59.21) and chlorophyll-a (52.36) and the TSI (SD) was 53.93 Eutrophication occurrences will cause serious limitations in water use applicability. This research contributes to the biogeographical and limnological understanding of the Pergau catchment, as well as laying the groundwork for more sophisticated hydro-ecological investigations. Anthropogenic activities, together with runoff from agricultural operations and the presence of algae, are some of the sources of contamination noted in the study. Stricter legislation, stricter enforcement of current standards, matching of non-technical and technosocial remedial actions, and education are among the recommendations made for the Pergau Reservoir's protection.

SPIE Proceedings, 2003

The feasibility of using digital camera imagery for estimating the concentration of total suspend... more The feasibility of using digital camera imagery for estimating the concentration of total suspended sediments (TSS) in the Timah Tasoh reservoir was investigated. Digital images were captured from a low-altitude light aircraft. Three selected images were mosaiced to produce bigger image of the study area. Atmospheric corrections and mosaic sincronourization were performed by using the average digital number of grass

Japan Geoscience Union, 2015

Wadi Siham Basin (WSB) is one of the most important agricultural areas, and one of the seven larg... more Wadi Siham Basin (WSB) is one of the most important agricultural areas, and one of the seven largest wadis in the western region of the Republic of Yemen. This study aims to evaluate the quantity and spatial and temporal variation of rainfall and runoff. The rainfall (1979-2008) as well as runoff and floods (1990-2009) data were collected and treated statistically in order to evaluate the rainfall and runoff trends. The areal catchment rainfall was estimated by using the Thiessen polygon method, while the recurrence interval and probability analysis were carried out using the Hazen method. The Mann?Kendall and Sen’s slope analyses results showed that the Wallan and Al-Amir stations produced significant negative values (-4.72 and -6.11 mm/year respectively). However, the rainfall trend in Dhamar had a significant positive value of 50.20 mm/year. The average annual rainfall in WSB was 346.39 mm/year. The total amount of rainfall was 1711.26 Mm . The mean annual water runoff was 82.92 ...

Abstrak 'Kesihatan' sesebuah lembangan saliran akan dicerminkan oleh kualiti air yang bai... more Abstrak 'Kesihatan' sesebuah lembangan saliran akan dicerminkan oleh kualiti air yang baik. Warna dan kekeruhan air adalah salah satu parameter yang mencerminkan sesuatu kualiti air dan ia berkaitan dengan kepekatan sedimen terampai yang terdapat di dalamnya. Sedimen yang terhasil daripada proses hakisan di dalam sesebuah kawasan tadahan akan memasuki anak-anak sungai dan tasik dan beban sedimen serta kekeruhan air akan menyebabkan banyak masalah kepada organisma hidup di dalam air. Pada masa kini, tanah telah menjadi salah satu sumber yang dihadkan di Pulau Pinang disebabkan oleh keadaan topografinya yang berbukit dan tanah rata yang agak terhad. Pulau Pinang merupakan sebuah bandar perindustrian yang pesat serta padat dan dalam rangka menghadapi cabaran masa depan yang disebabkan oleh kepesatan pembangunan ekonomi dan terdapat permintaan yang tinggi bagi keperluan kawasan tanah rata. Pelbagai aktiviti dan pembukaan tanah ini seterusnya memberi sumbangan terhadap kepekatan ...

Urban runoff is responsible for water quality deterioration of receiving water downstream of urba... more Urban runoff is responsible for water quality deterioration of receiving water downstream of urban areas. Lately new engineering approaches that integrate ecological consideration had been used to combat urban drainage issues such as erosion and water quality. BioEcological Drainage System (BIOECODS) is an example of integration of engineering and ecological components to solve urban runoff. BIOECODS at USM Engineering Campus in Nibong Tebal, Penang, combines three engineering techniques to manage storm water based on control at source approach by integrating the drainage components with ecological components (i.e constructed wetland, detention pond, wading stream and recreational ponds). This paper reports our findings of the water quality parameters of water bodies in the ecological components conducted from April 2003–September 2003 every fortnight water sampling strategy. Results suggested that most of the water quality parameters improved from detention pond towards recreationa...

Indian Journal of Scientific Research, 2014

Typhoons are significant events around the world, and can cause large-scale damage. This study is... more Typhoons are significant events around the world, and can cause large-scale damage. This study is an effort to dedicate the variations of typhoon activities during 1970-2011 over Asia-Pacific region. The data of typhoons through the paper were achieved from IBTrACS data set, and the data of sea surface temperature were obtained from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) data archives. Changes of typhoon characteristics were examined by analyzing the 6-hourly data during the period. The outcomes showed that the possibility of a typhoon event was highest in the area between 10-30˚N30˚N and 120-140˚E140˚E. In addition, typhoon intensity, in the case of wind speed of higher than 118 km/h, had a maximum percentage of 36.9. For minimum central pressure, the amount of 1000 to 990 mbar had the highest percentage of 25.1. Furthermore, the typhoon event had a dropping trend in the recent decade. The results also showed that the number of typhoons and the standard deviation of sea surface temperature had an inversely connection.

This study, statistically describes variations of the total heat flux during typhoons over the So... more This study, statistically describes variations of the total heat flux during typhoons over the South China Sea. Total heat flux was considered as a sum of the latent heat flux (LHF) and sensible heat flux (SHF). Typhoons in the South China Sea were selected from 1991 to 2011. These effects were examined based on archived data from the National Centers for Environmental Prediction and the National Center for Atmospheric Research (NCEP-NCAR) and the number of typhoons from the Joint Typhoon Warning Center during the indicated period. A long-term study on typhoons behavior indicated that on average, the trend of overall heat flux is related to the number of typhoons. By contrast, the results showed that the total heat flux touched its maximum amounts in July and August, and prepared the required energy for typhoon generation, so the number of typhoons enhanced during consequent months, August and September which had maximum number of typhoons during the years. Furthermore, from the spa...

Bukit Merah Reservoir (BMR) is one of the 51 impoundments in Malaysia. BMR is the oldest reservoi... more Bukit Merah Reservoir (BMR) is one of the 51 impoundments in Malaysia. BMR is the oldest reservoir built in the early 1900s originally to store water for irrigation, but nowadays its functions include also flood control and water supply. Nowadays, it is threatened by land use change in the upper catchments and surrounding activities, which feeding eroded material and chemicals into the reservoir. Suspended sediment, as well as, nutrient fluxes into BMR are becoming an increasing threat to the reservoir, as its sedimentation and eutrophication accelerate. This paper discusses our study on the BMR carried out between March 2008 and April 2009 to assess the water quality status, and to determine the sediment and Total Phosphorus (TP) influx into the south pool lake. An estimated amount of suspended sediment fluxes of about 2,900 t year-1 came from the north pool lake (18%) and 12,900 t year-1 from the main Kurau River inlet (82% of the total input to the BMR). Of these total sediment i...

Rivers and lakes are natural heritage that should be preserved at all cost. The history of human ... more Rivers and lakes are natural heritage that should be preserved at all cost. The history of human civilisation has proven the importance of rivers and lakes to humans but development activities had changed the water quality status of rivers and lakes. Due to pollution, they are no longer of any use to human beings. This study was conducted to evaluate the changes of water quality in major rivers, lakes and dams in the northern region of Peninsular Malaysia. Sampling was carried out in February 2010 and completed in April of the same year. The sampling consisted of 62 sampling stations located in rivers, lakes and dams in Perlis, Kedah and Penang. Readings were taken based on 11 hydrological and physicochemical parameters and the water quality status was classified under the Interim National Water Quality Standards (INWQS) which tabulated six levels of pollution ranging from moderate to extremely polluted in the order of I, IIA, IIB, III, IV and V. Results from the study show that mos...

Geografia: Malaysian journal of society and space, 2017

Environmental impact induced by rapid urbanization and development may be traced from changes in ... more Environmental impact induced by rapid urbanization and development may be traced from changes in local rainfall trends and variations. This study examined the trends and variations of rainfall in the Kinta River basin, Perak, a region in Malaysia that is rapidly urbanizing and developing. Long-term rainfall data from the year 1960 to 2006 were obtained from the Department of Irrigation and Drainage (DID) involving 15 rainfall stations in the Kinta River basin were employed to analyse long-term variations and precipitation trends. Results of the Mann-Kendall tests show that the Kinta River basin received high rainfall during the Northeast monsoon (950 mm) as compared to that received during the Southwest monsoon (309 mm). The tests also showed that the annual rainfall in the Kinta River basin had an increasing trend from the year 1960-2006 with the value of S=217 as did the monthly rainfall (except in the months of June and July 8) and seasonal rainfall during Northeast monsoon (S = ...

This study was based on plots under various types of land use and covers at North Pool, Bukit Mer... more This study was based on plots under various types of land use and covers at North Pool, Bukit Merah Reservoir (BMR) catchment. The rainfall was generated from a rainfall simulator to produce constant intensity of 53 mm/hour. Runoff, sediment and nutrient losses were measured. The results show that sediment concentration was highest from the bare soil plot (429.80 mg/L), and the lowest is from the grass plot (135.80 mg/L). Soil types in the catchment area also influenced the infiltration rate and the amount of surface runoff. The result also shows that the nutrient concentration in the totality of all forms of nitrogen is highest from the bare soil plot. This is due to the highest surface runoff were generated and the top layer soil was exposed to erosion activities of flowing water. The highest implication to the catchment management or soil conservation and nutrient retention has deteriorated water quality supplying to Bukit Merah reservoir. In controlling this problem, best manage...

A small drainage basin (0.5 km2) was selected on the Relau hill to evaluate sediment and nutrient... more A small drainage basin (0.5 km2) was selected on the Relau hill to evaluate sediment and nutrient export. Stream flow gauging, water depth and gulp water samples were collected manually on a weekly basis between November 2001 to October 2002 with additional gauging and water samples taken during storm events. The concentrations of sediment and nutrient were analysed to determine the quality of the river water and the health of the catchment. The highestsuspended sediment concentrations and nutrients concentration in upper Relau catchment are, in most cases, associated with periods of high discharge during the monitoring period. Hysteresis relationships between SSC, NO3-N, TN, orthophosphate and TP concentration with discharge (Q) shows some form of pattern of variation during the monitoring period. The hysteresis approach was used to identify the sources of SSC, NO3-N and orthophosphate in streams. The findings from this study are common to most drainage systems having seasonal bimo...

A study was carried of out to assess the sediment balance of a shallow Timah Tasoh Reservoir (Are... more A study was carried of out to assess the sediment balance of a shallow Timah Tasoh Reservoir (Area: 191 km2). Streamflow gauging and water sampling was carried out at three river inputs to the reservoir, and at the reservoir outlets. River water samplings were carried out every two weeks but frequent and intensive sampling during storm events. The land use in the catchment area ranging from urban area to agriculture, sugar cane, rubber, paddy, rural villages, smalltowns, quarrying and mining activities. Suspended sediment load data was used to derive the sediment balance. Jarum River (S1), Upper Pelarit River (S2) and Chuchuh River (S3) produced 10,032.3 t; 6,439.2 t; 1,061.4 t of sediment respectively while suspended sediment yield in S1, S2 and S3 were 155.8 tkm-2yr-1, 150.7 tkm-2yr-1, and 71.7 tkm-2yr-1 respectively. Storms play a major role in transporting sediment from the catchment areas. Almost 88.7% of the total suspended sediment yield is transported from S1, 56.7% from S2 ...

Proceeding Environmental Health, 2012

Dataran banjir yang merupakan habitat bagi gabungan pelbagai jenis hidupan adalah terbentuk darip... more Dataran banjir yang merupakan habitat bagi gabungan pelbagai jenis hidupan adalah terbentuk daripada hasil interaksi pelbagai jenis tindak balas sungai, perkembangan musim, dan keakraban hubungan dataran banjir dengan habitat di sekitarnya. Banjir yang telah berlaku pada masa lampau telah memendapkan sejumlah endapan atau sedimen lalu membentuk dataran banjir. Oleh itu, sistem dataran banjir amat bergantung kepada darjah kebolehubahan pelbagai bahagian di dataran banjir terhadap kekerapan dan tempoh banjir. Kertas kerja ini dibuat bagi meninjau kesan pelbagai regim hidrologi dalam mempengaruhi ciri-ciri lapisan endapan di dataran banjir seterusnya melihat bagaimana perbezaan ciri lapisan endapan ini mempengaruhi proses transformasi dan variasi kandungan nutrien di dalam lapisan endapan tersebut. Bagi mencapai matlamat ini, tiga stesen telah dipilih di sepanjang Sungai Muda iaitu stesen Merbau Pulas, Ekor Kucing dan Kemumbung. Setiap stesen yang dipilih telah dikorek secara menegak untuk mendapatkan sampel tanih bagi setiap 2cm lapisan endapan. Kesemua sampel bagi stesen-stesen ini telah dibawa ke makmal dan dianalisis dengan parameter-parameter seperti saiz partikel, ketumpatan pukal, pH, kandungan bahan organik tanih, dan juga kandungan nutrien seperti nitrogen, fosforus dan kalium. Ciri-ciri sedimen ini adalah penting kerana berpotensi untuk menunjukkan dan merakam petanda perubahan iklim seterusnya ia juga memainkan peranan dalam pembentukan landskap.

This study investigated the trophic conditions and water quality of three selected lakes of diffe... more This study investigated the trophic conditions and water quality of three selected lakes of different trophy namely Dayang Bunting Lake (oligotrophy-mesotrophy), Subang Reservoir (mesotrophyeutrophy)
and Sembrong Reservoir (eutrophy-hyper eutrophy) with the objective to characterize a trophic classification for Malaysian lakes. The study assessed various environmental variables including chlorophyll-a, total phosphorus, total nitrogen, dissolved oxygen, pH, turbidity and water transparency. Our results showed a low transparency in all lakes which ranged from 0.2 to 3.7 m. Dayang Bunting Lake has the highest transparency, salinity and conductivity among the lakes. Mean concentration of chlorophyll-a was below 10 μg/L while mean Secchi depth transparency exceeded 3.0m indicating oligotrophic-mesotrophic environment. TP concentrations were lowest in Dayang Bunting compared to other lakes. Sembrong Reservoir has the highest turbidity and chlorophyll-a, and lowest transparency among the lakes. Mean concentration of chlorophyll-a in this reservoir exceeded 25 μg/L, indicating eutrophic to hyper-eutrophic environment. The physical-chemical properties of Subang reservoir, such as turbidity, transparency, dissolved oxygen and nitrate, were in between the two lakes. TSI differences indicated both Subang and Sembrong reservoirs are non-phosphorus limited while Dayang Bunting Lake is phosphorus limited. Sembrong Reservoir was dominated by cyanobacteria, such as Planktothrix and Oscillatoria spp while Subang Lake was dominated by green algae. The most common algae in Dayang Bunting Lake were dinoflagellates and diatoms, indicating the influence of the adjacent marine waters.

Miratul Maghfiroh, Aan DLake Ecosystem Health and Its Resilience: Diversity and Risks of Extinction Proceedings of the 16 th World Lake Conference, 7-11 Nov 2016, Bali, Indonesia, 2017

This study investigated the trophic conditions and water quality of three selected lakes of diffe... more This study investigated the trophic conditions and water quality of three selected lakes of different trophy namely Dayang Bunting Lake (oligotrophy-mesotrophy), Subang Reservoir (mesotrophy-eutrophy) and
Sembrong Reservoir (eutrophy-hyper eutrophy) with the objective to characterize a trophic classification for Malaysian lakes. The study assessed various environmental variables including chlorophyll-a, total
phosphorus, total nitrogen, dissolved oxygen, pH, turbidity and water transparency. Our results showed a low transparency in all lakes which ranged from 0.2 to 3.7 m. Dayang Bunting Lake has the highest transparency, salinity and conductivity among the lakes. Mean concentration of chlorophyll-a was below 10 µg/L while mean
Secchi depth transparency exceeded 3.0 m indicating oligotrophic-mesotrophic environment. TP concentrations were lowest in Dayang Bunting compared to other lakes. Sembrong Reservoir has the highest turbidity and chlorophyll-a, and lowest transparency among the lakes. Mean concentration of chlorophyll-a in this reservoir exceeded 25 µg/L, indicating eutrophic to hyper-eutrophic environment. The physical-chemical properties of Subang reservoir, such as turbidity, transparency, dissolved oxygen and nitrate, were in between the two lakes. TSI differences indicated both Subang and Sembrong reservoirs are non-phosphorus limited while Dayang Bunting Lake is phosphorus limited. Sembrong Reservoir was dominated by cyanobacteria, such as Planktothrix and Oscillatoria spp while Subang Lake was dominated by green algae. The most common algae in Dayang Bunting Lake were dinoflagellates and diatoms, indicating the influence of the adjacent marine waters.

Zati Sharip, F.M. Yusoff, W.R. Ismail, S. Suratman & A. Mohamed (Eds). A survey on water quality and some biological communities in selected lakes of Malaysia , 2017

Water quality is a general term that refers to a general description of the properties of a wate... more Water quality is a general term that refers to a general description of the properties of a water body. Lakes that have high water quality possess properties that make them highly valued resource to society and nature. Water quality is also an important concern for both human use of lakes and other freshwaters as well as the ecological value of water bodies. Water quality is used in determining the state of aquatic environments and is an interesting point of study. A healthy aquatic ecosystem depends on its physico-chemical and biological characteristics. The quality of water in any ecosystem provides significant information about the available resources for supporting life in that ecosystem. Lake water quality is important for recreational purposes. Thus, it is imperative that a good water quality be maintained for the economy of Langkawi. The water quality of TDB should be monitored from time to time. This chapter describes our assessment of the water quality of a small freshwater lake- Tasik Dayang Bunting or Lake of Pregnant Maiden, located on the Dayang Bunting Island, the second largest uninhabited island in Langkawi.