For the past decades, the number of research on Non Point Source (NPS) pollution has increased du... more For the past decades, the number of research on Non Point Source (NPS) pollution has increased due to its nature being the major source of pollution to water degradation around the world. The study of NPS in Malaysia is scarce especially in agricultural areas. This research aims to provide quality and quantity of runoff pollutant loadings from an agricultural farm at a plot scale. Two plots were constructed at different land use (fruit orchard and vegetable farm). Tipping bucket flow gauges were installed at the end of each slope to measure runoff volume and collect water sample. The water samples were collected over a period of three months, immediately following rainfall events. Nine water parameter (Nitrite, Nitrate, Ammonia, Total Nitrogen, Phosphate, Total Phosphorus, Chemical Oxygen Demand, Total Suspended Solid, pH) analyses were conducted by using the DR5000 UV-Spectrometer. Result indicated that Total Suspended Solid (TSS) from fruit orchard is much higher while the nutrien...
Journal of Urban and Environmental Engineering, 2019
The search for an accurate evapotranspiration (ET) continues when the world has responsibility to... more The search for an accurate evapotranspiration (ET) continues when the world has responsibility to cope with the water scarcity issue, population outgrown and uncertain change of weather. Measuring actual evapotranspiration (ETa) can be tedious and requires a lot of time and cost. Therefore, numbers of empirical ET models have been developed to overcome this problem. The Valiantzas’ models are quite familiar to the hydrologist community as it has been developed based on Penman evaporation equation. This paper presents the evaluation on the selected six Valiantzas’ models by comparing to Food and Agricultural Organization Penman-Montieth (FAO-PM) empirical model in estimating ET in the Peninsular Malaysia. Seventeen meteorological stations around Peninsular Malaysia with data gathered from 1987 till 2003 were tested. The performance for each model was evaluated by root mean square error (RMSE), coefficient of determination (R2), percentage error (PE) and mean bias error (MBE). All the...
IOP Conference Series: Earth and Environmental Science, 2021
The present study is part of the development of an environment-friendly water management system b... more The present study is part of the development of an environment-friendly water management system based on sub surface drainage technology. It is aimed at creating a multipurpose farmland with expectation of increase in both benefits and productivity. Sub-surface drainage pipes which are installed inside mole-drain, functions as water channel that flows water into the drainage channel. Simulation was run using a 2D numerical soil water flow model based on Richard’s equation. It integrates varying soil textures with aim of figuring the optimum setting of sub-drains in response to soil textures. The depth of sub-drain was established at 40cm beneath the surface for all conditions as it is the current installation available in Indonesia. Our simulation shows the variation of soil moisture and pressure over distance, time and different textures under specified spacing of sub-surface installation.
A few experiments have been conducted to examine an artificial macropores and their size effects ... more A few experiments have been conducted to examine an artificial macropores and their size effects on water flow and solute transport [1-4]. Allaire-Leung, et al. [ I ] found that water percolation rate with open-open (0-0) macropore was two orders or magnitude higher than those with no macropore. Similarly, Zhou, et al, [2] found that the infiltration rate in the 0-0 macropore was 10-50 times greater than those with no macropore and the other macropore types in their treatment. Biopori has become recently popular approach in reducing surface runoff. However, the effect of its diameter and length on different soil types has not been numerically investigated. The water flow through a loamy soil (2mm sieved and 15% of initial water content) containing an artificial cylindrical macropore having 8 cm in diameter and 9 cm in length was observed through a soil column having 20 cm in diameter and 20 cm in height HYDRUS 2D/3D was employed to simulate the water now of the observed data. Water ...
The relationship between heavy metal and trophic properties in polymictic lake at Sembrong Lake, ... more The relationship between heavy metal and trophic properties in polymictic lake at Sembrong Lake, Peninsular Malaysia was assessed. Sixteen parameters, including heavy metals and trophic parameters were monitored. pH, temperature, dissolved oxygen and heavy metals level changes significantly influenced by the dynamic of polymictic mixing pattern. The mean concentrations of heavy metals in the reservoir decreased in the following order: Fe > Mn > Zn > Cu > As > Pb. The result showed that this polymictic lake is being threatened by cultural eutrophication with TSI value range from 72.40 to 80.41 and classified as a hypereutrophic lake. The levels of heavy metal pollution in the reservoir range from slightly polluted to polluted. Factor analysis was performed to determine the relationship between heavy metals and trophic parameters. Five factors were responsible for data structure and explained the 83% of total variance. These factors differentiate each group of parameter...
Many studies have examined the individual macropores and their size effects on water flow and sol... more Many studies have examined the individual macropores and their size effects on water flow and solute transport. However, the effects of macropore size on reducing surface runoff has not been scientically studied. The present study describes a laboratorium experiment and examine the effects of macropore dimensions and changes in initial soil water content on the cumulative infiltration and the occurrence of first time drainage. The water flow through a loamy soil (2mm sieved and 15% of initial water content) containing an artificial cylindrical macropore having 8 cm in diameter and 9 cm in height was observed through a soil column having 20 cm in diameter and 20 cm in height. HYDRUS 2D/3D was employed to simulate the water flow through the soil at 5 cm. 8 cm. and 10 cm in diameters: and 10 cm. 20 cm and 50 cm in heights of the macropore. Three contrasting initial soil water contents: 15%. 20%. and 25% was applied into the treatment of different sizes of macropore diameters. Overall, ...
For the past decades, the number of research on Non Point Source (NPS) pollution has increased du... more For the past decades, the number of research on Non Point Source (NPS) pollution has increased due to its nature being the major source of pollution to water degradation around the world. The study of NPS in Malaysia is scarce especially in agricultural areas. This research aims to provide quality and quantity of runoff pollutant loadings from an agricultural farm at a plot scale. Two plots were constructed at different land use (fruit orchard and vegetable farm). Tipping bucket flow gauges were installed at the end of each slope to measure runoff volume and collect water sample. The water samples were collected over a period of three months, immediately following rainfall events. Nine water parameter (Nitrite, Nitrate, Ammonia, Total Nitrogen, Phosphate, Total Phosphorus, Chemical Oxygen Demand, Total Suspended Solid, pH) analyses were conducted by using the DR5000 UV-Spectrometer. Result indicated that Total Suspended Solid (TSS) from fruit orchard is much higher while the nutrien...
Soil losses from hill slopes in oil palm plantation in Sedenak Estate, Johor were measured using ... more Soil losses from hill slopes in oil palm plantation in Sedenak Estate, Johor were measured using runoff plots and rainfall simulator. The plot was designed to be removable but the size was fixed at 0.8 x 3.75m. Four types of surface covers were applied for the plots i.e. half bare soil and grass cover (HGC), half bare soil and dry frond (HDF), fully grass cover (FG), and fully bare soil (BS). The effects of physical soil factors such as soil moisture and saturated hydraulics conductivity, Ks along with land slope were also evaluated. The rainfall simulator produced rainfall intensities between 90 and 160 mm/hr with durations from 45 to 60 min per run. BS exhibited the highest Ks value among all surface plots but the percentage of soil moisture on this surface was low. The results indicate that there are significant differences in runoff generation and soil loss production with respects to different types of surface cover. The lowest runoff coefficient (ROC) was produced on BS with t...
The possible occurrence of stratification was assessed in Sembrong reservoir located in Kluang, J... more The possible occurrence of stratification was assessed in Sembrong reservoir located in Kluang, Johor, Peninsular Malaysia. It is a man-made reservoir. Profile samplings were conducted at eight points. Water samples at each point were collected at discrete depth intervals of 1m. In situ measurement of Temperature , pH, Conductivity and Oxidation Reduction Potential (ORP) were carried out using Hydrolab DSX5. Water samples were analysed in lab for Fe, Al and Mn using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES).The results show that pH, temperature and ORP tend to decrease after 3m depth. On the other hand, concentrations of Fe, Mn and Al slightly increased with depth as a result of reduction process. This phenomenon confirms the occurrence of reservoir stratification
ARPN journal of engineering and applied sciences, 2015
Empirical equations to describe flow duration curve (FDC) are mostly in the form of exponential, ... more Empirical equations to describe flow duration curve (FDC) are mostly in the form of exponential, logarithmic, power or even polynomial functions but none of these fit the dataset of the study site of this research. This paper proposed two new empirical functions, modified from soil water retention equations. The efficiency and prediction accuracy of our new empirical equations were evaluated against each mentioned common function at the study site. Polynomial function was discarded as it failed to fit the dataset. Power function over-predicted nearly every quantile and induced un-acceptable huge difference especially at high flow end of the FDC. Logarithmic was the only function that yields negative predicted low flow and under predicted peak flow by 85%. On the other hand, exponential function almost under predicted peak flows by 100%. New empirical equations have highest Nash-Sutcliffe efficiency with lowest overall RMSE, quantile cumulative RMSE at high flow range and percentage ...
Sensitivity of the FAO Penman-Monteith (FPM) potential evapotranspiration (PET) model under tropi... more Sensitivity of the FAO Penman-Monteith (FPM) potential evapotranspiration (PET) model under tropical climates has been studied in the present study. A total of 17 meteorological stations covering Peninsular Malaysia starting from 1987-2003 were used as model inputs. A sensitivity analysis (SA) was carried out using the graphical method for temperature, wind speed and solar radiation within the possible range of ±20% with increments of 5%. From the comparison done on the sensitivity of PET to climatic change, the Kuala Krai station gave the highest percentage change in terms of temperature (±6%). The highest percentage change for wind speed (±2%) and solar radiation (±17%) were shown at the Alor Setar and Kuala Krai stations, respectively. The Alor Setar station had the lowest percentage change for temperature (±0.3%) and solar radiation (±9.9). The lowest percentage change of wind speed (± 0.2%) was observed at the Kuala Krai station. PET percentage changes have a positive correlati...
The possible occurrence of stratification was assessed in Sembrong reservoir located in Kluang, J... more The possible occurrence of stratification was assessed in Sembrong reservoir located in Kluang, Johor, Peninsular Malaysia. It is a man-made reservoir. Profile samplings were conducted at eight points. Water samples at each point were collected at discrete depth intervals of 1m. In situ measurement of Temperature , pH, Conductivity and Oxidation Reduction Potential (ORP) were carried out using Hydrolab DSX5. Water samples were analysed in lab for Fe, Al and Mn using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES).The results show that pH, temperature and ORP tend to decrease after 3m depth. On the other hand, concentrations of Fe, Mn and Al slightly increased with depth as a result of reduction process. This phenomenon confirms the occurrence of reservoir stratification
Cloud detection over water surfaces is difficult due to the sun glint effect. The mixed pixels be... more Cloud detection over water surfaces is difficult due to the sun glint effect. The mixed pixels between both features may introduce inaccurate cloud classification. This problem generally occurs because of less contrast between the glint and the cloud. Both features have almost the same reflectance in the visible wavelength. The piecewise contrast stretch technique shows preservation capability on the reflectance of the cloud. The result of a band ratio was smoothed by applying the Sobel edge detection to provide better cloud feature detection. The study achieved an accuracy of about 77.5% in cloud pixels detection.
For the past decades, the number of research on Non Point Source (NPS) pollution has increased du... more For the past decades, the number of research on Non Point Source (NPS) pollution has increased due to its nature being the major source of pollution to water degradation around the world. The study of NPS in Malaysia is scarce especially in agricultural areas. This research aims to provide quality and quantity of runoff pollutant loadings from an agricultural farm at a plot scale. Two plots were constructed at different land use (fruit orchard and vegetable farm). Tipping bucket flow gauges were installed at the end of each slope to measure runoff volume and collect water sample. The water samples were collected over a period of three months, immediately following rainfall events. Nine water parameter (Nitrite, Nitrate, Ammonia, Total Nitrogen, Phosphate, Total Phosphorus, Chemical Oxygen Demand, Total Suspended Solid, pH) analyses were conducted by using the DR5000 UV-Spectrometer. Result indicated that Total Suspended Solid (TSS) from fruit orchard is much higher while the nutrien...
Journal of Urban and Environmental Engineering, 2019
The search for an accurate evapotranspiration (ET) continues when the world has responsibility to... more The search for an accurate evapotranspiration (ET) continues when the world has responsibility to cope with the water scarcity issue, population outgrown and uncertain change of weather. Measuring actual evapotranspiration (ETa) can be tedious and requires a lot of time and cost. Therefore, numbers of empirical ET models have been developed to overcome this problem. The Valiantzas’ models are quite familiar to the hydrologist community as it has been developed based on Penman evaporation equation. This paper presents the evaluation on the selected six Valiantzas’ models by comparing to Food and Agricultural Organization Penman-Montieth (FAO-PM) empirical model in estimating ET in the Peninsular Malaysia. Seventeen meteorological stations around Peninsular Malaysia with data gathered from 1987 till 2003 were tested. The performance for each model was evaluated by root mean square error (RMSE), coefficient of determination (R2), percentage error (PE) and mean bias error (MBE). All the...
IOP Conference Series: Earth and Environmental Science, 2021
The present study is part of the development of an environment-friendly water management system b... more The present study is part of the development of an environment-friendly water management system based on sub surface drainage technology. It is aimed at creating a multipurpose farmland with expectation of increase in both benefits and productivity. Sub-surface drainage pipes which are installed inside mole-drain, functions as water channel that flows water into the drainage channel. Simulation was run using a 2D numerical soil water flow model based on Richard’s equation. It integrates varying soil textures with aim of figuring the optimum setting of sub-drains in response to soil textures. The depth of sub-drain was established at 40cm beneath the surface for all conditions as it is the current installation available in Indonesia. Our simulation shows the variation of soil moisture and pressure over distance, time and different textures under specified spacing of sub-surface installation.
A few experiments have been conducted to examine an artificial macropores and their size effects ... more A few experiments have been conducted to examine an artificial macropores and their size effects on water flow and solute transport [1-4]. Allaire-Leung, et al. [ I ] found that water percolation rate with open-open (0-0) macropore was two orders or magnitude higher than those with no macropore. Similarly, Zhou, et al, [2] found that the infiltration rate in the 0-0 macropore was 10-50 times greater than those with no macropore and the other macropore types in their treatment. Biopori has become recently popular approach in reducing surface runoff. However, the effect of its diameter and length on different soil types has not been numerically investigated. The water flow through a loamy soil (2mm sieved and 15% of initial water content) containing an artificial cylindrical macropore having 8 cm in diameter and 9 cm in length was observed through a soil column having 20 cm in diameter and 20 cm in height HYDRUS 2D/3D was employed to simulate the water now of the observed data. Water ...
The relationship between heavy metal and trophic properties in polymictic lake at Sembrong Lake, ... more The relationship between heavy metal and trophic properties in polymictic lake at Sembrong Lake, Peninsular Malaysia was assessed. Sixteen parameters, including heavy metals and trophic parameters were monitored. pH, temperature, dissolved oxygen and heavy metals level changes significantly influenced by the dynamic of polymictic mixing pattern. The mean concentrations of heavy metals in the reservoir decreased in the following order: Fe > Mn > Zn > Cu > As > Pb. The result showed that this polymictic lake is being threatened by cultural eutrophication with TSI value range from 72.40 to 80.41 and classified as a hypereutrophic lake. The levels of heavy metal pollution in the reservoir range from slightly polluted to polluted. Factor analysis was performed to determine the relationship between heavy metals and trophic parameters. Five factors were responsible for data structure and explained the 83% of total variance. These factors differentiate each group of parameter...
Many studies have examined the individual macropores and their size effects on water flow and sol... more Many studies have examined the individual macropores and their size effects on water flow and solute transport. However, the effects of macropore size on reducing surface runoff has not been scientically studied. The present study describes a laboratorium experiment and examine the effects of macropore dimensions and changes in initial soil water content on the cumulative infiltration and the occurrence of first time drainage. The water flow through a loamy soil (2mm sieved and 15% of initial water content) containing an artificial cylindrical macropore having 8 cm in diameter and 9 cm in height was observed through a soil column having 20 cm in diameter and 20 cm in height. HYDRUS 2D/3D was employed to simulate the water flow through the soil at 5 cm. 8 cm. and 10 cm in diameters: and 10 cm. 20 cm and 50 cm in heights of the macropore. Three contrasting initial soil water contents: 15%. 20%. and 25% was applied into the treatment of different sizes of macropore diameters. Overall, ...
For the past decades, the number of research on Non Point Source (NPS) pollution has increased du... more For the past decades, the number of research on Non Point Source (NPS) pollution has increased due to its nature being the major source of pollution to water degradation around the world. The study of NPS in Malaysia is scarce especially in agricultural areas. This research aims to provide quality and quantity of runoff pollutant loadings from an agricultural farm at a plot scale. Two plots were constructed at different land use (fruit orchard and vegetable farm). Tipping bucket flow gauges were installed at the end of each slope to measure runoff volume and collect water sample. The water samples were collected over a period of three months, immediately following rainfall events. Nine water parameter (Nitrite, Nitrate, Ammonia, Total Nitrogen, Phosphate, Total Phosphorus, Chemical Oxygen Demand, Total Suspended Solid, pH) analyses were conducted by using the DR5000 UV-Spectrometer. Result indicated that Total Suspended Solid (TSS) from fruit orchard is much higher while the nutrien...
Soil losses from hill slopes in oil palm plantation in Sedenak Estate, Johor were measured using ... more Soil losses from hill slopes in oil palm plantation in Sedenak Estate, Johor were measured using runoff plots and rainfall simulator. The plot was designed to be removable but the size was fixed at 0.8 x 3.75m. Four types of surface covers were applied for the plots i.e. half bare soil and grass cover (HGC), half bare soil and dry frond (HDF), fully grass cover (FG), and fully bare soil (BS). The effects of physical soil factors such as soil moisture and saturated hydraulics conductivity, Ks along with land slope were also evaluated. The rainfall simulator produced rainfall intensities between 90 and 160 mm/hr with durations from 45 to 60 min per run. BS exhibited the highest Ks value among all surface plots but the percentage of soil moisture on this surface was low. The results indicate that there are significant differences in runoff generation and soil loss production with respects to different types of surface cover. The lowest runoff coefficient (ROC) was produced on BS with t...
The possible occurrence of stratification was assessed in Sembrong reservoir located in Kluang, J... more The possible occurrence of stratification was assessed in Sembrong reservoir located in Kluang, Johor, Peninsular Malaysia. It is a man-made reservoir. Profile samplings were conducted at eight points. Water samples at each point were collected at discrete depth intervals of 1m. In situ measurement of Temperature , pH, Conductivity and Oxidation Reduction Potential (ORP) were carried out using Hydrolab DSX5. Water samples were analysed in lab for Fe, Al and Mn using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES).The results show that pH, temperature and ORP tend to decrease after 3m depth. On the other hand, concentrations of Fe, Mn and Al slightly increased with depth as a result of reduction process. This phenomenon confirms the occurrence of reservoir stratification
ARPN journal of engineering and applied sciences, 2015
Empirical equations to describe flow duration curve (FDC) are mostly in the form of exponential, ... more Empirical equations to describe flow duration curve (FDC) are mostly in the form of exponential, logarithmic, power or even polynomial functions but none of these fit the dataset of the study site of this research. This paper proposed two new empirical functions, modified from soil water retention equations. The efficiency and prediction accuracy of our new empirical equations were evaluated against each mentioned common function at the study site. Polynomial function was discarded as it failed to fit the dataset. Power function over-predicted nearly every quantile and induced un-acceptable huge difference especially at high flow end of the FDC. Logarithmic was the only function that yields negative predicted low flow and under predicted peak flow by 85%. On the other hand, exponential function almost under predicted peak flows by 100%. New empirical equations have highest Nash-Sutcliffe efficiency with lowest overall RMSE, quantile cumulative RMSE at high flow range and percentage ...
Sensitivity of the FAO Penman-Monteith (FPM) potential evapotranspiration (PET) model under tropi... more Sensitivity of the FAO Penman-Monteith (FPM) potential evapotranspiration (PET) model under tropical climates has been studied in the present study. A total of 17 meteorological stations covering Peninsular Malaysia starting from 1987-2003 were used as model inputs. A sensitivity analysis (SA) was carried out using the graphical method for temperature, wind speed and solar radiation within the possible range of ±20% with increments of 5%. From the comparison done on the sensitivity of PET to climatic change, the Kuala Krai station gave the highest percentage change in terms of temperature (±6%). The highest percentage change for wind speed (±2%) and solar radiation (±17%) were shown at the Alor Setar and Kuala Krai stations, respectively. The Alor Setar station had the lowest percentage change for temperature (±0.3%) and solar radiation (±9.9). The lowest percentage change of wind speed (± 0.2%) was observed at the Kuala Krai station. PET percentage changes have a positive correlati...
The possible occurrence of stratification was assessed in Sembrong reservoir located in Kluang, J... more The possible occurrence of stratification was assessed in Sembrong reservoir located in Kluang, Johor, Peninsular Malaysia. It is a man-made reservoir. Profile samplings were conducted at eight points. Water samples at each point were collected at discrete depth intervals of 1m. In situ measurement of Temperature , pH, Conductivity and Oxidation Reduction Potential (ORP) were carried out using Hydrolab DSX5. Water samples were analysed in lab for Fe, Al and Mn using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES).The results show that pH, temperature and ORP tend to decrease after 3m depth. On the other hand, concentrations of Fe, Mn and Al slightly increased with depth as a result of reduction process. This phenomenon confirms the occurrence of reservoir stratification
Cloud detection over water surfaces is difficult due to the sun glint effect. The mixed pixels be... more Cloud detection over water surfaces is difficult due to the sun glint effect. The mixed pixels between both features may introduce inaccurate cloud classification. This problem generally occurs because of less contrast between the glint and the cloud. Both features have almost the same reflectance in the visible wavelength. The piecewise contrast stretch technique shows preservation capability on the reflectance of the cloud. The result of a band ratio was smoothed by applying the Sobel edge detection to provide better cloud feature detection. The study achieved an accuracy of about 77.5% in cloud pixels detection.
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