Abstract Southeast Asia (SEA) is a socio-economically and environmentally dynamic region of the w... more Abstract Southeast Asia (SEA) is a socio-economically and environmentally dynamic region of the world, with abundant renewable freshwater resources. At the same time, the population of the region is increasing and leading towards unsustainable water use and strict water management. The overall environmental flow status of Southeast Asian Rivers is assessed in this study, which is based on a critical review of the available literature of some important river basins of the study area. The results show that all riparian countries of the Mekong River are trying to utilize the hydropower potential of the river where more than 12,000 dams are constructed, which leads to significant alteration of hydrological regime in all tributaries of MRB. The two influential countries China and India are sharing the Brahmaputra River, where both countries are planning to construct dams. The 400 planned dams on this river will make the area the most concentrated region of the world in terms of big dam construction, while the low lying areas in India and Bangladesh are posing the threat of nutrient pollution due to excessive agricultural activities. The Citarum River in Indonesia is suffering from overburden of pollution, which makes the river heavily polluted while the Muda river in Malaysia is facing a lack of Integrated Water Resources Management (IWRM) and lack of stakeholders’ engagement. Moreover, many of river basins in rest of SEA countries i.e. Lao PDR, Cambodia, Viet Nam, Myanmar, Philippines, Brunei Darussalam, and East Timor are lacking attention to research and policy to this field, therefore, the status of Environmental Flow is ranked unsatisfactory in most river basins of SEA.
Backwater flow refers to the occurrence of abnormal flood waters causing by inflow water from maj... more Backwater flow refers to the occurrence of abnormal flood waters causing by inflow water from major to tributary streams. At Sungai Chini, inflow from Sungai Pahang brings high suspended sediments which contributed to active sediment fine deposition. This article discusses the results on sediment size determination that was carried out in Sungai Chini in two different seasons, namely normal season (16/8/08) and rainy season (4/12/08). Three sampling stations were selected. Parameters used in this study are based on grain size distribution (g). Different size of material classifications were determined and calculated using Phi scale (o) in order to calculate their median, mean (M), standard deviation (D) and skewness (S). River flow estimation (m3/s) and some other hydraulic data were also calculated for modeling and simulation using XP-SWMM software. Simulations carried out aimed to evaluate the actual flow that occurred during the study period as well as to identify current problem...
Tropical rivers and wetlands are recognized as one of the greatest and most abundant ecosystems i... more Tropical rivers and wetlands are recognized as one of the greatest and most abundant ecosystems in terms of ecological and social benefits. However, climate change, damming, overfishing, water pollution, and the introduction of exotic species threaten these ecosystems, which puts about 65% of river flow and aquatic ecosystems under a moderate to high level of threat. This paper aims to assess the environmental flow of the Selangor River based on the hydrological index method using the Global Environmental Flow Calculator (GEFC) and Indicators of Hydrological Alterations (IHA) software. The daily flow data collected by the Department of Irrigation and Drainage (DID), Malaysia, over a 60-year period (1960–2020) was used in this study to assess the Selangor River flow alterations. As per the results, the river flow has had two distinct periods over the last 60 years. In the first period, the river flows without any alteration and has a natural flow with high flood pulses and low flow p...
Using 15 sampling stations, study was conducted to assess the water quality parameters of samples... more Using 15 sampling stations, study was conducted to assess the water quality parameters of samples collected from River Galma, Zaria, Northwestern Nigeria, in wet and dry seasons. This was achieved using analysis of independent samples test (t-test), hierarchical cluster analysis (HCA), and principal component analysis (PCA) techniques. Analysis of the t-test results shows that, out of the 18 water quality parameters analyzed, 9 parameters were statistically significant (p< 0.05), while the remaining parameters were statistically significant at p> 0.05 for both seasons and all the concentration of the water quality parameters results increases during dry season, which may be attributed to water evaporation and absence of rainfall. HCA identified 4 and 3 different groups in wet season (WS) and dry seasons (DS) from 18 water quality parameters, which indicate that the variation in water quality are due to natural and anthropogenic processes. Two components resulted from PCA analysis from both WS and DS. PCA explained 79.33% of the total variance in the variables which are included in the component in WS and 80.09% of the total variance in the variables which are included in the component in DS, in which the major sources of pollution are related to agriculture and other human activities. From this study, it shows that application of environmetric multivariate techniques are significant to environmental management and the result will help stakeholders in decision making toward sustainable management support of the river system.
The massive amount of urban litter in Malaysia is influenced by rapid population growth, developm... more The massive amount of urban litter in Malaysia is influenced by rapid population growth, development, economic growth and unsustainable lifestyles. Few studies have assessed the amount of urban litter load and its composition at gross pollutant trap (GPT), significantly contributing to lack of historical data. This study is aimed to assess the amount of urban litter load in wet basis condition at individual GPTs along Sungai Batu, Selangor in 2015. The urban litter collection data at each GPT in 2015 were sourced from Department of Irrigation and Drainage (DID). Samples were manually collected once a month, stored in plastic bag and immediately weighed and recorded by following the ASCE standard method. The result shows that the total amount of urban litter load in 2015 was 3761.72 kg/year (Mean ± SD; 313.4767 ± 141.9105 kg/year). In such situations, further study on urban litter load and its composition trapped at GPTs is urgently required as it is crucial to establish baseline dat...
The estimation of excess rainfall is critically important in water resource management as it prov... more The estimation of excess rainfall is critically important in water resource management as it provides the basis for calculating flood peak discharge that results in surface runoff. Kelantan River basin in Malaysia is a tropical catchment receiving heavy monsoon rainfall coupled with intense land use/cover (LULC) changes making the area consistently flood prone. The current study is therefore aimed to achieve the following goals: (1) to develop a curve number (CN) and runoff maps for 1984, 2002, and 2013 LULC conditions and (2) to determine runoff dynamics due to changes in LULC as well as to assess how the extent of LULC change will affect surface runoff generation. To achieve the aforementioned goals, land use maps corresponding to 1984, 2002, and 2014 LULC conditions were analyzed and prepared for the calculation of CN values using Soil Conservation Service (SCS-CN) method. CN and runoff maps corresponding to 1984, 2002, and 2013 LULC changes were successfully developed and the performance of the method was tested. The results indicated that forest was found to be the major land use type to have changed in all the LULC conditions across the watershed leading to intense runoff dynamics in the entire watershed. Higher runoff values were observed under 2013 LULC conditions across the watershed mainly due to intense deforestation relative to those of 1984 and 2002. The results of this study indicated that runoff generation is significantly affected by deforestation instead of changes in the rainfall pattern. The findings may be useful to water resource planners in controlling water loss for future planning.
The accumulation of floatable litter in the river is mainly influenced by the increasing number o... more The accumulation of floatable litter in the river is mainly influenced by the increasing number of human population, rapid urbanization and development which indirectly lead to the changes of hydrological processes in river discharge, decreasing the water quality and aesthetical value of the river. The main objective of this paper is to determine the cumulative floatable litter load captured at the log boom during the extreme events by using the Gumbel distribution method for frequency analysis in river discharge of Sungai Batu. The annual maximum river discharge for a period of 35 years (1982 to 2016) was used in Gumbel distribution method to obtain the discharge for different return period (2, 5, 10, 25, 50, 100, and 200). The result shows that the estimated discharge (103.17 m³/s) can estimate the cumulative floatable litter load (53267.27 kg/day) at 50 years return period. The R2 value obtained from non – linear regression analysis is 0.9986 indicate that Gumbel distribution is ...
The devastating effect of soil erosion is one of the major sources of land degradation that affec... more The devastating effect of soil erosion is one of the major sources of land degradation that affects human lives in many ways which occur mainly due to deforestation, poor agricultural practices, overgrazing, wildfire and urbanization. Soil erosion often leads to soil truncation, loss of fertility, slope instability, etc. which causes irreversible effects on the poorly renewable soil resource. In view of this, a study was conducted in Kelantan River basin to predict soil loss as influenced by long-term land use/land-cover (LULC) changes in the area. The study was conducted with the aim of predicting and assessing soil erosion as it is influenced by long-term LULC changes. The 13,100 km 2 watershed was delineated into four sub-catchments Galas, Pergau, Lebir and Nenggiri for precise result estimation and ease of execution. GIS-based Universal Soil Loss Equation (USLE) model was used to predict soil loss in this study. The model inputs used for the temporal and spatial calculation of soil erosion include rainfall erosivity factor, topographic factor, land cover and management factor as well as erodibility factor. The results showed that 67.54% of soil loss is located under low erosion potential (reversible soil loss) or 0e1 t ha À1 yr À1 soil loss in Galas, 59.17% in Pergau, 53.32% in Lebir and 56.76% in Nenggiri all under the 2013 LULC condition. Results from the correlation of soil erosion rates with LULC changes indicated that cleared land in all the four catchments and under all LULC conditions (1984e2013) appears to be the dominant with the highest erosion losses. Similarly, grassland and forest were also observed to regulate erosion rates in the area. This is because the vegetation cover provided by these LULC types protects the soil from direct impact of rain drops which invariably reduce soil loss to the barest minimum. Overall, it was concluded that the results have shown the significance of LULC in the control of erosion. Maps generated from the study may be useful to planners and land use managers to take appropriate decisions for soil conservation. Ó 2017, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).
The contribution of non-point source pollution (NPS) to the contamination of surface water is an ... more The contribution of non-point source pollution (NPS) to the contamination of surface water is an issue of growing concern. Non-point source (NPS) pollutants are of various types and altered by several site-specific factors making them difficult to control due to complex uncertainties involve in their behavior. Kelantan River basin, Malaysia is a tropical catchment receiving heavy monsoon rainfall coupled with intense land use/land cover (LULC) changes making the area consistently flood prone thereby deteriorating the surface water quality in the area. This study was conducted to determine the spatio-temporal variation of NPS pollutant loads among different LULC changes and to establish a NPS pollutant loads relationships among LULC conditions and sub-basins in each catchment. Four pollutants parameters such as total suspended solids (TSS), total phosphorus (TP), total nitrogen (TN) and ammonia nitrogen (AN) were chosen with their corresponding event mean concentration values (EMC). Soil map and LULC change maps corresponding to 1984, 2002 and 2013 were used for the calculation of runoff and NPS pollutant loads using numeric integration in a GIS environment. Analysis of Variance (ANOVA) was conducted for the comparison of NPS pollutant loads among the three LULC conditions used and the sub-basins in each catchment. The results showed that the spatio-temporal variation of pollutant loads in almost all the catchments increased with changes in LULC condition as one moves from 1984 to 2013, with 2013 LULC condition found as the dominant in almost all cases. NPS pollutant loads among different LULC changes also increased with changes in LULC condition from 1984 to 2013. While urbanization was found to be the dominant LULC change with the highest pollutant load in all the catchments. Results from ANOVA reveals that statistically most significant (p < 0.05) pollutant loads were obtained from 2013 LULC conditions, while statistically least significant (p < 0.05) pollutant loads were obtained under 1984 LULC condition. This reveals the clear effect of LULC changes on NPS pollution. The findings of this study may be useful to water resource planners in controlling water pollution for future planning. Keywords Hydrologic impact · Remote sensing · Non-point source pollution · GIS · Malaysia
Rainfall characteristics are directly related to the climate of a basin, but this can only be not... more Rainfall characteristics are directly related to the climate of a basin, but this can only be noticed after a long period. Human activities, such as deforestation, tend to play a major role in transforming the land use land cover (LULC). Knowledge of the relationship between design floods and LULC is important in modeling and designing watershed management strategies. A study was conducted in the Kelantan River basin, Malaysia, to determine the impact of past and present LULC changes on peak discharge and runoff volumes. To achieve this, the basin was delineated into four catchments (Galas, Pergau, Nenggiri, and Lebir) due to its size and increased precision. Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) model was calibrated based on December 20–30th, 2014, flood in Kelantan. Flood hydrographs corresponding to 1984, 2002, and 2013 LULC conditions were simulated, and relative changes in peak discharge and runoff volume were determined for different return periods (2, 5, 10, 20, 50, 100 years). Results of LULC analysis showed that Galas recorded highest deforestation (54.35%). When the four catchments were compared with respect to highest contribution of outlet peak discharge, Lebir under 2013 LULC condition was the highest with 2847.70 m 3 /s. This was followed by Nenggiri (2196.90 m 3 /s), Galas (1252.7 m 3 /s), and Pergau (328.7 m 3 /s), all under the 2013 LULC condition. Results of unit response approach applied based on 50-year return period to the catchments for ranking their sub-basins revealed that the novel fa index developed in this study provides a better way of ranking sub-basins with respect to their contribution to the outlet and therefore is recommended for use. Methodologies developed in this study may be useful to land use planners from around the world which when applied can provide alternatives that will minimize the adverse effects of floods. Keywords Design floods. Land use land cover changes. Kelantan River basin. GIS. HEC-HMS
Study region: Hadejia River Basin (HRB) in North Eastern Nigeria. Study focus: The hydrological t... more Study region: Hadejia River Basin (HRB) in North Eastern Nigeria. Study focus: The hydrological trends and variations of surface runoff in Hadejia river catchment were assessed using data spanning 36 years (1980–2015) for proper planning and management of water resources in the basin. New hydrological insight for the region: The temporal and spatial irregularities in the runoff of Hadeia river catchment has been detected. A significant decrease of river discharge from two out of the three downstream stations had been observed. However, there is an increasing trend of the river discharge from all the three upstream stations, though statistically insignificant. The ANOVA [F (5,210) = 106.226, P < 0.05] and cluster analysis results showed significant spatial variations between the upstream and downstream stations. The increasing trend of the discharge in the upstream stations is attributable to high rainfall mean and increased urbanization in the area. However, the significant decreasing trend of the discharge downstream of the river catchment is associated to many factors, notably; high evaporation rate due to high temperature, low rainfall mean and the relatively high infiltration rate encouraged by the high percentage of sandy soil and the sedimentary geological formation. Consequent to these trends and variations, water supply and irrigation, particularly in the downstream areas are at risk. Thus, integrated basin study using hydrological modelling will be helpful to distinguish the individual impact of the blame factors and to predict the river discharge behavior in response to the impact of those factors.
Abstract Southeast Asia (SEA) is a socio-economically and environmentally dynamic region of the w... more Abstract Southeast Asia (SEA) is a socio-economically and environmentally dynamic region of the world, with abundant renewable freshwater resources. At the same time, the population of the region is increasing and leading towards unsustainable water use and strict water management. The overall environmental flow status of Southeast Asian Rivers is assessed in this study, which is based on a critical review of the available literature of some important river basins of the study area. The results show that all riparian countries of the Mekong River are trying to utilize the hydropower potential of the river where more than 12,000 dams are constructed, which leads to significant alteration of hydrological regime in all tributaries of MRB. The two influential countries China and India are sharing the Brahmaputra River, where both countries are planning to construct dams. The 400 planned dams on this river will make the area the most concentrated region of the world in terms of big dam construction, while the low lying areas in India and Bangladesh are posing the threat of nutrient pollution due to excessive agricultural activities. The Citarum River in Indonesia is suffering from overburden of pollution, which makes the river heavily polluted while the Muda river in Malaysia is facing a lack of Integrated Water Resources Management (IWRM) and lack of stakeholders’ engagement. Moreover, many of river basins in rest of SEA countries i.e. Lao PDR, Cambodia, Viet Nam, Myanmar, Philippines, Brunei Darussalam, and East Timor are lacking attention to research and policy to this field, therefore, the status of Environmental Flow is ranked unsatisfactory in most river basins of SEA.
Backwater flow refers to the occurrence of abnormal flood waters causing by inflow water from maj... more Backwater flow refers to the occurrence of abnormal flood waters causing by inflow water from major to tributary streams. At Sungai Chini, inflow from Sungai Pahang brings high suspended sediments which contributed to active sediment fine deposition. This article discusses the results on sediment size determination that was carried out in Sungai Chini in two different seasons, namely normal season (16/8/08) and rainy season (4/12/08). Three sampling stations were selected. Parameters used in this study are based on grain size distribution (g). Different size of material classifications were determined and calculated using Phi scale (o) in order to calculate their median, mean (M), standard deviation (D) and skewness (S). River flow estimation (m3/s) and some other hydraulic data were also calculated for modeling and simulation using XP-SWMM software. Simulations carried out aimed to evaluate the actual flow that occurred during the study period as well as to identify current problem...
Tropical rivers and wetlands are recognized as one of the greatest and most abundant ecosystems i... more Tropical rivers and wetlands are recognized as one of the greatest and most abundant ecosystems in terms of ecological and social benefits. However, climate change, damming, overfishing, water pollution, and the introduction of exotic species threaten these ecosystems, which puts about 65% of river flow and aquatic ecosystems under a moderate to high level of threat. This paper aims to assess the environmental flow of the Selangor River based on the hydrological index method using the Global Environmental Flow Calculator (GEFC) and Indicators of Hydrological Alterations (IHA) software. The daily flow data collected by the Department of Irrigation and Drainage (DID), Malaysia, over a 60-year period (1960–2020) was used in this study to assess the Selangor River flow alterations. As per the results, the river flow has had two distinct periods over the last 60 years. In the first period, the river flows without any alteration and has a natural flow with high flood pulses and low flow p...
Using 15 sampling stations, study was conducted to assess the water quality parameters of samples... more Using 15 sampling stations, study was conducted to assess the water quality parameters of samples collected from River Galma, Zaria, Northwestern Nigeria, in wet and dry seasons. This was achieved using analysis of independent samples test (t-test), hierarchical cluster analysis (HCA), and principal component analysis (PCA) techniques. Analysis of the t-test results shows that, out of the 18 water quality parameters analyzed, 9 parameters were statistically significant (p< 0.05), while the remaining parameters were statistically significant at p> 0.05 for both seasons and all the concentration of the water quality parameters results increases during dry season, which may be attributed to water evaporation and absence of rainfall. HCA identified 4 and 3 different groups in wet season (WS) and dry seasons (DS) from 18 water quality parameters, which indicate that the variation in water quality are due to natural and anthropogenic processes. Two components resulted from PCA analysis from both WS and DS. PCA explained 79.33% of the total variance in the variables which are included in the component in WS and 80.09% of the total variance in the variables which are included in the component in DS, in which the major sources of pollution are related to agriculture and other human activities. From this study, it shows that application of environmetric multivariate techniques are significant to environmental management and the result will help stakeholders in decision making toward sustainable management support of the river system.
The massive amount of urban litter in Malaysia is influenced by rapid population growth, developm... more The massive amount of urban litter in Malaysia is influenced by rapid population growth, development, economic growth and unsustainable lifestyles. Few studies have assessed the amount of urban litter load and its composition at gross pollutant trap (GPT), significantly contributing to lack of historical data. This study is aimed to assess the amount of urban litter load in wet basis condition at individual GPTs along Sungai Batu, Selangor in 2015. The urban litter collection data at each GPT in 2015 were sourced from Department of Irrigation and Drainage (DID). Samples were manually collected once a month, stored in plastic bag and immediately weighed and recorded by following the ASCE standard method. The result shows that the total amount of urban litter load in 2015 was 3761.72 kg/year (Mean ± SD; 313.4767 ± 141.9105 kg/year). In such situations, further study on urban litter load and its composition trapped at GPTs is urgently required as it is crucial to establish baseline dat...
The estimation of excess rainfall is critically important in water resource management as it prov... more The estimation of excess rainfall is critically important in water resource management as it provides the basis for calculating flood peak discharge that results in surface runoff. Kelantan River basin in Malaysia is a tropical catchment receiving heavy monsoon rainfall coupled with intense land use/cover (LULC) changes making the area consistently flood prone. The current study is therefore aimed to achieve the following goals: (1) to develop a curve number (CN) and runoff maps for 1984, 2002, and 2013 LULC conditions and (2) to determine runoff dynamics due to changes in LULC as well as to assess how the extent of LULC change will affect surface runoff generation. To achieve the aforementioned goals, land use maps corresponding to 1984, 2002, and 2014 LULC conditions were analyzed and prepared for the calculation of CN values using Soil Conservation Service (SCS-CN) method. CN and runoff maps corresponding to 1984, 2002, and 2013 LULC changes were successfully developed and the performance of the method was tested. The results indicated that forest was found to be the major land use type to have changed in all the LULC conditions across the watershed leading to intense runoff dynamics in the entire watershed. Higher runoff values were observed under 2013 LULC conditions across the watershed mainly due to intense deforestation relative to those of 1984 and 2002. The results of this study indicated that runoff generation is significantly affected by deforestation instead of changes in the rainfall pattern. The findings may be useful to water resource planners in controlling water loss for future planning.
The accumulation of floatable litter in the river is mainly influenced by the increasing number o... more The accumulation of floatable litter in the river is mainly influenced by the increasing number of human population, rapid urbanization and development which indirectly lead to the changes of hydrological processes in river discharge, decreasing the water quality and aesthetical value of the river. The main objective of this paper is to determine the cumulative floatable litter load captured at the log boom during the extreme events by using the Gumbel distribution method for frequency analysis in river discharge of Sungai Batu. The annual maximum river discharge for a period of 35 years (1982 to 2016) was used in Gumbel distribution method to obtain the discharge for different return period (2, 5, 10, 25, 50, 100, and 200). The result shows that the estimated discharge (103.17 m³/s) can estimate the cumulative floatable litter load (53267.27 kg/day) at 50 years return period. The R2 value obtained from non – linear regression analysis is 0.9986 indicate that Gumbel distribution is ...
The devastating effect of soil erosion is one of the major sources of land degradation that affec... more The devastating effect of soil erosion is one of the major sources of land degradation that affects human lives in many ways which occur mainly due to deforestation, poor agricultural practices, overgrazing, wildfire and urbanization. Soil erosion often leads to soil truncation, loss of fertility, slope instability, etc. which causes irreversible effects on the poorly renewable soil resource. In view of this, a study was conducted in Kelantan River basin to predict soil loss as influenced by long-term land use/land-cover (LULC) changes in the area. The study was conducted with the aim of predicting and assessing soil erosion as it is influenced by long-term LULC changes. The 13,100 km 2 watershed was delineated into four sub-catchments Galas, Pergau, Lebir and Nenggiri for precise result estimation and ease of execution. GIS-based Universal Soil Loss Equation (USLE) model was used to predict soil loss in this study. The model inputs used for the temporal and spatial calculation of soil erosion include rainfall erosivity factor, topographic factor, land cover and management factor as well as erodibility factor. The results showed that 67.54% of soil loss is located under low erosion potential (reversible soil loss) or 0e1 t ha À1 yr À1 soil loss in Galas, 59.17% in Pergau, 53.32% in Lebir and 56.76% in Nenggiri all under the 2013 LULC condition. Results from the correlation of soil erosion rates with LULC changes indicated that cleared land in all the four catchments and under all LULC conditions (1984e2013) appears to be the dominant with the highest erosion losses. Similarly, grassland and forest were also observed to regulate erosion rates in the area. This is because the vegetation cover provided by these LULC types protects the soil from direct impact of rain drops which invariably reduce soil loss to the barest minimum. Overall, it was concluded that the results have shown the significance of LULC in the control of erosion. Maps generated from the study may be useful to planners and land use managers to take appropriate decisions for soil conservation. Ó 2017, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).
The contribution of non-point source pollution (NPS) to the contamination of surface water is an ... more The contribution of non-point source pollution (NPS) to the contamination of surface water is an issue of growing concern. Non-point source (NPS) pollutants are of various types and altered by several site-specific factors making them difficult to control due to complex uncertainties involve in their behavior. Kelantan River basin, Malaysia is a tropical catchment receiving heavy monsoon rainfall coupled with intense land use/land cover (LULC) changes making the area consistently flood prone thereby deteriorating the surface water quality in the area. This study was conducted to determine the spatio-temporal variation of NPS pollutant loads among different LULC changes and to establish a NPS pollutant loads relationships among LULC conditions and sub-basins in each catchment. Four pollutants parameters such as total suspended solids (TSS), total phosphorus (TP), total nitrogen (TN) and ammonia nitrogen (AN) were chosen with their corresponding event mean concentration values (EMC). Soil map and LULC change maps corresponding to 1984, 2002 and 2013 were used for the calculation of runoff and NPS pollutant loads using numeric integration in a GIS environment. Analysis of Variance (ANOVA) was conducted for the comparison of NPS pollutant loads among the three LULC conditions used and the sub-basins in each catchment. The results showed that the spatio-temporal variation of pollutant loads in almost all the catchments increased with changes in LULC condition as one moves from 1984 to 2013, with 2013 LULC condition found as the dominant in almost all cases. NPS pollutant loads among different LULC changes also increased with changes in LULC condition from 1984 to 2013. While urbanization was found to be the dominant LULC change with the highest pollutant load in all the catchments. Results from ANOVA reveals that statistically most significant (p < 0.05) pollutant loads were obtained from 2013 LULC conditions, while statistically least significant (p < 0.05) pollutant loads were obtained under 1984 LULC condition. This reveals the clear effect of LULC changes on NPS pollution. The findings of this study may be useful to water resource planners in controlling water pollution for future planning. Keywords Hydrologic impact · Remote sensing · Non-point source pollution · GIS · Malaysia
Rainfall characteristics are directly related to the climate of a basin, but this can only be not... more Rainfall characteristics are directly related to the climate of a basin, but this can only be noticed after a long period. Human activities, such as deforestation, tend to play a major role in transforming the land use land cover (LULC). Knowledge of the relationship between design floods and LULC is important in modeling and designing watershed management strategies. A study was conducted in the Kelantan River basin, Malaysia, to determine the impact of past and present LULC changes on peak discharge and runoff volumes. To achieve this, the basin was delineated into four catchments (Galas, Pergau, Nenggiri, and Lebir) due to its size and increased precision. Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) model was calibrated based on December 20–30th, 2014, flood in Kelantan. Flood hydrographs corresponding to 1984, 2002, and 2013 LULC conditions were simulated, and relative changes in peak discharge and runoff volume were determined for different return periods (2, 5, 10, 20, 50, 100 years). Results of LULC analysis showed that Galas recorded highest deforestation (54.35%). When the four catchments were compared with respect to highest contribution of outlet peak discharge, Lebir under 2013 LULC condition was the highest with 2847.70 m 3 /s. This was followed by Nenggiri (2196.90 m 3 /s), Galas (1252.7 m 3 /s), and Pergau (328.7 m 3 /s), all under the 2013 LULC condition. Results of unit response approach applied based on 50-year return period to the catchments for ranking their sub-basins revealed that the novel fa index developed in this study provides a better way of ranking sub-basins with respect to their contribution to the outlet and therefore is recommended for use. Methodologies developed in this study may be useful to land use planners from around the world which when applied can provide alternatives that will minimize the adverse effects of floods. Keywords Design floods. Land use land cover changes. Kelantan River basin. GIS. HEC-HMS
Study region: Hadejia River Basin (HRB) in North Eastern Nigeria. Study focus: The hydrological t... more Study region: Hadejia River Basin (HRB) in North Eastern Nigeria. Study focus: The hydrological trends and variations of surface runoff in Hadejia river catchment were assessed using data spanning 36 years (1980–2015) for proper planning and management of water resources in the basin. New hydrological insight for the region: The temporal and spatial irregularities in the runoff of Hadeia river catchment has been detected. A significant decrease of river discharge from two out of the three downstream stations had been observed. However, there is an increasing trend of the river discharge from all the three upstream stations, though statistically insignificant. The ANOVA [F (5,210) = 106.226, P < 0.05] and cluster analysis results showed significant spatial variations between the upstream and downstream stations. The increasing trend of the discharge in the upstream stations is attributable to high rainfall mean and increased urbanization in the area. However, the significant decreasing trend of the discharge downstream of the river catchment is associated to many factors, notably; high evaporation rate due to high temperature, low rainfall mean and the relatively high infiltration rate encouraged by the high percentage of sandy soil and the sedimentary geological formation. Consequent to these trends and variations, water supply and irrigation, particularly in the downstream areas are at risk. Thus, integrated basin study using hydrological modelling will be helpful to distinguish the individual impact of the blame factors and to predict the river discharge behavior in response to the impact of those factors.
Uploads
Papers by nor rohaizah jamil