Abstract: This study is focused on developing an integrated optimization-simulation model to deve... more Abstract: This study is focused on developing an integrated optimization-simulation model to develop the operation policies for a multi-purpose reservoir. Objective function of the optimization model is considered to be a linear function of reliability, resiliency, and vulnerability of river-reservoir systems. Genetic Algorithm (GA) is used to solve the optimization model in which the coefficients of the reservoir operation policy equations are considered as the decision variables. These coefficients are formulated in the form of fuzzy numbers to better capture the variations in releases and water demands. Due to significant variations of agricultural water demands in different months and years, a water demand time series is considered as one of the inputs of the optimization model. Zayandeh-rud River-reservoir system in central part of Iran is considered as the case study. Results of this study have shown that the developed algorithm can significantly reduce the time and costs of m...
Human activities in the recent years have considerably increased the rate of water pollution in m... more Human activities in the recent years have considerably increased the rate of water pollution in many regions of the world. In this case study, the main sources of wastewater discharging into the Gargar River were identified. Using river and point source flow rates and water quality parameters measured along the river, the river water quality was simulated using a commonly used, one-dimensional water quality model, the QUAL2K model. Simulated values of DO, CBOD, NH4-N and NO3-N demonstrated the accuracy of the model and despite a significant data shortage in the study area, QUAL2K model was found to be an acceptable tool for the assessment of water quality. Still, for this case study, it was found that the model was most sensitive to river and point source flows and moderate to fast CBOD oxidation, and nitrification rates.
ABSTRACT The most important drawback of standard fuzzy arithmetic is unrealistic accumulation of ... more ABSTRACT The most important drawback of standard fuzzy arithmetic is unrealistic accumulation of input uncertainties which results in divergence of fuzzy outputs. Some of the currently available methods of simulating fuzzy systems provide the results which tend to naive large values after several time steps of the system simulation. In this paper, a new fuzzy arithmetic operator based on fuzzy extension principle has been proposed for simulation and assessment of uncertainty in hydrological systems. Implementing the concept of fuzzy approximate reasoning in the proposed approach in this study represents acceptable behavior in uncertainty propagation from the parameters and structures of the models to the outputs. To show the efficiency of the proposed fuzzy arithmetic operator in the context of hydrologic modeling, two nonlinear monthly water balance models have been examined and their outputs have been compared with the results obtained by standard fuzzy arithmetic and the Vertex method. One small humid basin in France and a middle size basin in a semi-arid region in Iran have been the case studies of this research. In this paper, the lower and upper bounds and the most frequent values of the model parameters inferred from the sampling-simulation procedure have been used to define triangular fuzzy membership functions. Three statistical indicators have been used to evaluate efficiency of the methods based on the bracket observations and coverage of the uncertainty bounds. The estimated values of these indicators have shown that both Vertex and the proposed methods outperform standard fuzzy arithmetic. Also, the proposed method has provided better or roughly equal efficiencies compared with Vertex method over both basins.
AB STRACT: Rapid industrial growth in the province of Khuzestan in the south west of Iran has res... more AB STRACT: Rapid industrial growth in the province of Khuzestan in the south west of Iran has resulted in disposal of about 1750 tons of solid waste per day. Most of these industrial solid wastes including hazardous wastes are disposed without considering environmental issues. This has contributed considerably to the pollution of the environment. This paper introduces a framework in which to develop a master plan for industrial solid waste management. There are usually different criteria for evaluating the existing solid waste pollution loads and how effective the management schemes are. A multiple criteria decision making technique, namely Analytical Hierarchy Process (AHP), is used for ranking the industrial units based on their share in solid waste related environmental pollution and determining the share of each unit in total solid waste pollution load. In this framework, a comprehensive set of direct, indirect, and supporting projects are proposed for solid waste pollution cont...
Understanding the frequency of dust storms in each area and being mindful of temporal-spatial var... more Understanding the frequency of dust storms in each area and being mindful of temporal-spatial variation of this event can help to monitor and reduce the damages induced by dust events. Due to the increasing development of metamodels and their combination with optimization algorithms used to model and predict hydrological variables, machine learning models due to high accuracy in forecasting, in the form of a black box, have received a lot of attention. Therefore, in the present study, a hybrid approach is proposed to predict the Frequency of Dust Storm Days (FDSD) on a seasonal scale, which uses a combination of Lang Short Term Memory (LSTM) and Gated Recurrent Unit (GRU) neural networks. In this study, the performance of the proposed hybrid model was compared with a neural network based on Radial Basis Functions (RBF) and Support Vector Machine (SVM). For this purpose, hourly dust data and codes of the World Meteorological Organization were used on a seasonal scale with a statistic...
International Journal of Environmental Research, 2021
One of the key issues in managing water and energy systems is to incorporate the links between th... more One of the key issues in managing water and energy systems is to incorporate the links between these systems to ensure security of resources. In this research, using system dynamics (SD) approach for simulating water–energy (WE) nexus, SD-WE model was developed for 16 sub-basins of Gavkhuni basin in central Iran. Various water- and energy-saving policies were simulated and their effectiveness in improving resource security was evaluated using water- (WSI) and energy-saving (ESI) indices. The results indicated that the share of water-related energy consumption (20%, 6%, and 2% of total electricity, crude oil, and natural gas consumption) is higher than the energy-related water withdrawal (17% of industrial water withdrawal) in the basin-wide resource usage. The water-saving policies had a significant impact on both the basin’s energy and water resources. In contrast, energy-saving policies had a negligible influence on the basin’s water resources but a notable impact on the water resources used in the energy sector outside of the basin. In addition, SD-WE model simulations showed that agriculture was the most effective end-user on resource saving, by improving WSI and ESI as much as 22% and 5.7%, respectively. Finally, the results of this study indicated that SD-WE model can be used as a tool to illustrate the inter-linkages, synergies, and trade-offs between water and energy systems, where limited water and energy data are available and also can be used as a platform for water–energy nexus modeling in other basins. A system dynamics approach for simulating water–energy nexus was introduced. Water-related policies had a significant impact on both energy and water resources of the case study area. Energy-related policies had a negligible influence on water resources of the case study area. A system dynamics approach for simulating water–energy nexus was introduced. Water-related policies had a significant impact on both energy and water resources of the case study area. Energy-related policies had a negligible influence on water resources of the case study area.
Abstract This study aims at exploring ways of increasing adaptive capacity and reducing vulnerabi... more Abstract This study aims at exploring ways of increasing adaptive capacity and reducing vulnerability of farmers in the face of water scarcity through establishing a link between social network indicators and the dimensions of adaptive capacity. For this purpose, a Social Network Analysis (SNA) model along with a Structural Equation Model was developed to investigate the effects of SNA indices on the dimensions influencing the adaptive capacity of the water users in rural areas in the west of Iran. The developed model links participation in production and knowledge exchange with ten critical dimensions identified to affect the adaptive capacities of water resources users. The results indicated that the most important subdimensions affecting adaptive capacity were governance, innovation, and awareness. Also, the positive effects of individual and whole network level of indices on the adaptive capacity indicated high coherence in the study area and the ability of people to develop social learning to improve the adaptive capacity.
World Environmental and Water Resources Congress 2020, 2020
Many communities in arid and semi-arid areas rely on groundwater for drinking water. However, ant... more Many communities in arid and semi-arid areas rely on groundwater for drinking water. However, anthropogenic activities such as the use of fertilizers and human waste disposal impose the risk of nitrate pollution to the aquifers. With over 8.5 million population, Tehran, the capital of Iran, has experienced rapid population growth during the past decades while the majority of the city did not have a sewerage network and the main way of wastewater disposal was individual cesspits inside houses. The long-term discharge of raw wastewater in cesspits has increased nitrate concentration in the Tehran aquifer which serves as a source of one-third of drinking water for the city. Although the construction of a sewerage network seems vital for improving the groundwater quality, one of the main concerns of this network is the drawdown of the water table in aquifer due to reduced recharge. A dynamic mass-balance model is developed for simulating water quantity and nitrate concentration in Tehran aquifer in order to study the impacts of sewerage network on the quantity and quality of groundwater. Considering that the sewage disposal in cesspits is one of the main sources of recharge, the results show the construction of sewerage network does not necessarily result in a reduction of nitrate concentration in long-term. This seems to be mainly because the reduced aquifer recharge results in groundwater depletion and the depleted aquifer is more prone to pollution even with smaller amounts of pollutants. Based on this modeling approach, we suggest that the reduced recharge due to construction of sewerage network should be compensated by either reduction of groundwater withdrawal or managed artificial recharge. The results of this study can provide a step toward application of sustainable water resources management in arid and semi-arid areas where the cesspits and septic tanks are common for wastewater disposal.
Engineering, Construction and Architectural Management, 2021
PurposeThis paper proposes an innovative intelligent simulation-based construction planning frame... more PurposeThis paper proposes an innovative intelligent simulation-based construction planning framework that introduces a new approach to simulation-based construction planning.Design/methodology/approachIn this approach, the authors developed an ontological inference engine as an integrated part of a constraint-based simulation system that configures the construction processes, defines activities and manages resources considering a variety of requirements and constraints during the simulation. It allows for the incorporation of the latest project information and a deep level of construction planning knowledge in the planning. The construction planning knowledge is represented by an ontology and several semantic rules. Also, the proposed framework uses the project building information model (BIM) to extract information regarding the construction product and the relations between elements. The extracted information is then converted to an ontological format to be useable by the framewo...
Abstract In this study, an economic analysis module was added to the System Dynamics (SD) Water-F... more Abstract In this study, an economic analysis module was added to the System Dynamics (SD) Water-Food-Energy (WFE) nexus model developed by Ravar et al. (2020) for the Gavkhuni Basin located in central Iran. The case study area has been facing several water-related conflicts due to natural and anthropogenic water scarcity of the basin and severe long-term droughts possibly associated with climate change. To resolve conflicts between environmental, agricultural, industrial and domestic water users, various water consumption management policies were introduced by water user sectors. The consideration of the economic impacts of water consumption management policies can play a key role in efficient and sustainable water resources management. The main purpose of this study was to provide the decision makers with a clear picture of economic impacts and consequences of the water consumption management policies within the framework of WFE nexus assessment. Hidden subsidies provided for water resources and energy carriers were calculated to highlight the importance of the pricing policies. The obtained results for a 10-year simulation period indicated that by implementing the policy suggested by the agriculture sector, not only the average value added (VA) of this sector increased by about 19% but also the average inflow to Gavkhuni wetland rose by about 82%. By applying the policy suggested by the energy sector, the total cost of energy for water decreased by about 30% and total cost of water for energy diminished by about 61%, which contributed to decrease in subsidy for energy and water resources. Furthermore, allocating more water to chemical industries resulted in the improvement of the overall industrial VA. The results also indicated the suitable performance of the developed model in reflecting the cross-sectoral economic consequences of sectoral policies.
Journal of Water Resources Planning and Management, 2016
AbstractStochastic dual dynamic programming (SDDP) is a widely used technique for operation optim... more AbstractStochastic dual dynamic programming (SDDP) is a widely used technique for operation optimization of large-scale hydropower systems in which reservoir inflow uncertainty is modeled with discrete scenarios produced by statistical time series models, such as the family of periodic auto-regressive (PAR) models. It is a common practice in statistical modeling of hydrologic time series to fit a well-known probability distribution (usually normal distribution) to the data by applying proper transformation. Box-Cox transformation is a commonly used transformation in the case of normal distribution fitting. The convexity requirement of SDDP means that nonlinearly transformed time series cannot be used for statistical inflow model calibration. In this paper, a linear approximation is proposed to estimate the expected value of the next stage inflow. In the proposed approach, next-stage inflows are estimated by a model that uses transformed time series. Furthermore, using the proposed linear approximation, it...
Abstract: This study is focused on developing an integrated optimization-simulation model to deve... more Abstract: This study is focused on developing an integrated optimization-simulation model to develop the operation policies for a multi-purpose reservoir. Objective function of the optimization model is considered to be a linear function of reliability, resiliency, and vulnerability of river-reservoir systems. Genetic Algorithm (GA) is used to solve the optimization model in which the coefficients of the reservoir operation policy equations are considered as the decision variables. These coefficients are formulated in the form of fuzzy numbers to better capture the variations in releases and water demands. Due to significant variations of agricultural water demands in different months and years, a water demand time series is considered as one of the inputs of the optimization model. Zayandeh-rud River-reservoir system in central part of Iran is considered as the case study. Results of this study have shown that the developed algorithm can significantly reduce the time and costs of m...
Human activities in the recent years have considerably increased the rate of water pollution in m... more Human activities in the recent years have considerably increased the rate of water pollution in many regions of the world. In this case study, the main sources of wastewater discharging into the Gargar River were identified. Using river and point source flow rates and water quality parameters measured along the river, the river water quality was simulated using a commonly used, one-dimensional water quality model, the QUAL2K model. Simulated values of DO, CBOD, NH4-N and NO3-N demonstrated the accuracy of the model and despite a significant data shortage in the study area, QUAL2K model was found to be an acceptable tool for the assessment of water quality. Still, for this case study, it was found that the model was most sensitive to river and point source flows and moderate to fast CBOD oxidation, and nitrification rates.
ABSTRACT The most important drawback of standard fuzzy arithmetic is unrealistic accumulation of ... more ABSTRACT The most important drawback of standard fuzzy arithmetic is unrealistic accumulation of input uncertainties which results in divergence of fuzzy outputs. Some of the currently available methods of simulating fuzzy systems provide the results which tend to naive large values after several time steps of the system simulation. In this paper, a new fuzzy arithmetic operator based on fuzzy extension principle has been proposed for simulation and assessment of uncertainty in hydrological systems. Implementing the concept of fuzzy approximate reasoning in the proposed approach in this study represents acceptable behavior in uncertainty propagation from the parameters and structures of the models to the outputs. To show the efficiency of the proposed fuzzy arithmetic operator in the context of hydrologic modeling, two nonlinear monthly water balance models have been examined and their outputs have been compared with the results obtained by standard fuzzy arithmetic and the Vertex method. One small humid basin in France and a middle size basin in a semi-arid region in Iran have been the case studies of this research. In this paper, the lower and upper bounds and the most frequent values of the model parameters inferred from the sampling-simulation procedure have been used to define triangular fuzzy membership functions. Three statistical indicators have been used to evaluate efficiency of the methods based on the bracket observations and coverage of the uncertainty bounds. The estimated values of these indicators have shown that both Vertex and the proposed methods outperform standard fuzzy arithmetic. Also, the proposed method has provided better or roughly equal efficiencies compared with Vertex method over both basins.
AB STRACT: Rapid industrial growth in the province of Khuzestan in the south west of Iran has res... more AB STRACT: Rapid industrial growth in the province of Khuzestan in the south west of Iran has resulted in disposal of about 1750 tons of solid waste per day. Most of these industrial solid wastes including hazardous wastes are disposed without considering environmental issues. This has contributed considerably to the pollution of the environment. This paper introduces a framework in which to develop a master plan for industrial solid waste management. There are usually different criteria for evaluating the existing solid waste pollution loads and how effective the management schemes are. A multiple criteria decision making technique, namely Analytical Hierarchy Process (AHP), is used for ranking the industrial units based on their share in solid waste related environmental pollution and determining the share of each unit in total solid waste pollution load. In this framework, a comprehensive set of direct, indirect, and supporting projects are proposed for solid waste pollution cont...
Understanding the frequency of dust storms in each area and being mindful of temporal-spatial var... more Understanding the frequency of dust storms in each area and being mindful of temporal-spatial variation of this event can help to monitor and reduce the damages induced by dust events. Due to the increasing development of metamodels and their combination with optimization algorithms used to model and predict hydrological variables, machine learning models due to high accuracy in forecasting, in the form of a black box, have received a lot of attention. Therefore, in the present study, a hybrid approach is proposed to predict the Frequency of Dust Storm Days (FDSD) on a seasonal scale, which uses a combination of Lang Short Term Memory (LSTM) and Gated Recurrent Unit (GRU) neural networks. In this study, the performance of the proposed hybrid model was compared with a neural network based on Radial Basis Functions (RBF) and Support Vector Machine (SVM). For this purpose, hourly dust data and codes of the World Meteorological Organization were used on a seasonal scale with a statistic...
International Journal of Environmental Research, 2021
One of the key issues in managing water and energy systems is to incorporate the links between th... more One of the key issues in managing water and energy systems is to incorporate the links between these systems to ensure security of resources. In this research, using system dynamics (SD) approach for simulating water–energy (WE) nexus, SD-WE model was developed for 16 sub-basins of Gavkhuni basin in central Iran. Various water- and energy-saving policies were simulated and their effectiveness in improving resource security was evaluated using water- (WSI) and energy-saving (ESI) indices. The results indicated that the share of water-related energy consumption (20%, 6%, and 2% of total electricity, crude oil, and natural gas consumption) is higher than the energy-related water withdrawal (17% of industrial water withdrawal) in the basin-wide resource usage. The water-saving policies had a significant impact on both the basin’s energy and water resources. In contrast, energy-saving policies had a negligible influence on the basin’s water resources but a notable impact on the water resources used in the energy sector outside of the basin. In addition, SD-WE model simulations showed that agriculture was the most effective end-user on resource saving, by improving WSI and ESI as much as 22% and 5.7%, respectively. Finally, the results of this study indicated that SD-WE model can be used as a tool to illustrate the inter-linkages, synergies, and trade-offs between water and energy systems, where limited water and energy data are available and also can be used as a platform for water–energy nexus modeling in other basins. A system dynamics approach for simulating water–energy nexus was introduced. Water-related policies had a significant impact on both energy and water resources of the case study area. Energy-related policies had a negligible influence on water resources of the case study area. A system dynamics approach for simulating water–energy nexus was introduced. Water-related policies had a significant impact on both energy and water resources of the case study area. Energy-related policies had a negligible influence on water resources of the case study area.
Abstract This study aims at exploring ways of increasing adaptive capacity and reducing vulnerabi... more Abstract This study aims at exploring ways of increasing adaptive capacity and reducing vulnerability of farmers in the face of water scarcity through establishing a link between social network indicators and the dimensions of adaptive capacity. For this purpose, a Social Network Analysis (SNA) model along with a Structural Equation Model was developed to investigate the effects of SNA indices on the dimensions influencing the adaptive capacity of the water users in rural areas in the west of Iran. The developed model links participation in production and knowledge exchange with ten critical dimensions identified to affect the adaptive capacities of water resources users. The results indicated that the most important subdimensions affecting adaptive capacity were governance, innovation, and awareness. Also, the positive effects of individual and whole network level of indices on the adaptive capacity indicated high coherence in the study area and the ability of people to develop social learning to improve the adaptive capacity.
World Environmental and Water Resources Congress 2020, 2020
Many communities in arid and semi-arid areas rely on groundwater for drinking water. However, ant... more Many communities in arid and semi-arid areas rely on groundwater for drinking water. However, anthropogenic activities such as the use of fertilizers and human waste disposal impose the risk of nitrate pollution to the aquifers. With over 8.5 million population, Tehran, the capital of Iran, has experienced rapid population growth during the past decades while the majority of the city did not have a sewerage network and the main way of wastewater disposal was individual cesspits inside houses. The long-term discharge of raw wastewater in cesspits has increased nitrate concentration in the Tehran aquifer which serves as a source of one-third of drinking water for the city. Although the construction of a sewerage network seems vital for improving the groundwater quality, one of the main concerns of this network is the drawdown of the water table in aquifer due to reduced recharge. A dynamic mass-balance model is developed for simulating water quantity and nitrate concentration in Tehran aquifer in order to study the impacts of sewerage network on the quantity and quality of groundwater. Considering that the sewage disposal in cesspits is one of the main sources of recharge, the results show the construction of sewerage network does not necessarily result in a reduction of nitrate concentration in long-term. This seems to be mainly because the reduced aquifer recharge results in groundwater depletion and the depleted aquifer is more prone to pollution even with smaller amounts of pollutants. Based on this modeling approach, we suggest that the reduced recharge due to construction of sewerage network should be compensated by either reduction of groundwater withdrawal or managed artificial recharge. The results of this study can provide a step toward application of sustainable water resources management in arid and semi-arid areas where the cesspits and septic tanks are common for wastewater disposal.
Engineering, Construction and Architectural Management, 2021
PurposeThis paper proposes an innovative intelligent simulation-based construction planning frame... more PurposeThis paper proposes an innovative intelligent simulation-based construction planning framework that introduces a new approach to simulation-based construction planning.Design/methodology/approachIn this approach, the authors developed an ontological inference engine as an integrated part of a constraint-based simulation system that configures the construction processes, defines activities and manages resources considering a variety of requirements and constraints during the simulation. It allows for the incorporation of the latest project information and a deep level of construction planning knowledge in the planning. The construction planning knowledge is represented by an ontology and several semantic rules. Also, the proposed framework uses the project building information model (BIM) to extract information regarding the construction product and the relations between elements. The extracted information is then converted to an ontological format to be useable by the framewo...
Abstract In this study, an economic analysis module was added to the System Dynamics (SD) Water-F... more Abstract In this study, an economic analysis module was added to the System Dynamics (SD) Water-Food-Energy (WFE) nexus model developed by Ravar et al. (2020) for the Gavkhuni Basin located in central Iran. The case study area has been facing several water-related conflicts due to natural and anthropogenic water scarcity of the basin and severe long-term droughts possibly associated with climate change. To resolve conflicts between environmental, agricultural, industrial and domestic water users, various water consumption management policies were introduced by water user sectors. The consideration of the economic impacts of water consumption management policies can play a key role in efficient and sustainable water resources management. The main purpose of this study was to provide the decision makers with a clear picture of economic impacts and consequences of the water consumption management policies within the framework of WFE nexus assessment. Hidden subsidies provided for water resources and energy carriers were calculated to highlight the importance of the pricing policies. The obtained results for a 10-year simulation period indicated that by implementing the policy suggested by the agriculture sector, not only the average value added (VA) of this sector increased by about 19% but also the average inflow to Gavkhuni wetland rose by about 82%. By applying the policy suggested by the energy sector, the total cost of energy for water decreased by about 30% and total cost of water for energy diminished by about 61%, which contributed to decrease in subsidy for energy and water resources. Furthermore, allocating more water to chemical industries resulted in the improvement of the overall industrial VA. The results also indicated the suitable performance of the developed model in reflecting the cross-sectoral economic consequences of sectoral policies.
Journal of Water Resources Planning and Management, 2016
AbstractStochastic dual dynamic programming (SDDP) is a widely used technique for operation optim... more AbstractStochastic dual dynamic programming (SDDP) is a widely used technique for operation optimization of large-scale hydropower systems in which reservoir inflow uncertainty is modeled with discrete scenarios produced by statistical time series models, such as the family of periodic auto-regressive (PAR) models. It is a common practice in statistical modeling of hydrologic time series to fit a well-known probability distribution (usually normal distribution) to the data by applying proper transformation. Box-Cox transformation is a commonly used transformation in the case of normal distribution fitting. The convexity requirement of SDDP means that nonlinearly transformed time series cannot be used for statistical inflow model calibration. In this paper, a linear approximation is proposed to estimate the expected value of the next stage inflow. In the proposed approach, next-stage inflows are estimated by a model that uses transformed time series. Furthermore, using the proposed linear approximation, it...
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Papers by Banafsheh Zahraie