H. Ghased; A. Roozbahani; M. Hashemy Shahedany
Abstract
Introduction: Inter-basin water transfer projects include essential, various, complex parameters where mostly have a qualitative inherent. Making an appropriate decision on these projects have not been convenient due to diverse impacts and effectiveness of the parameters as well as irregular and qualitative ...
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Introduction: Inter-basin water transfer projects include essential, various, complex parameters where mostly have a qualitative inherent. Making an appropriate decision on these projects have not been convenient due to diverse impacts and effectiveness of the parameters as well as irregular and qualitative intrinsic of the criteria. The main objective of this study is the evaluating and prioritizing of the practical inter-basin water transfer scenarios to Central Plateau of Iran employing three approaches of the analytic hierarchy process (AHP), DEMATEL and Shannon Entropy, and proposing this approach for decision making in water resources.
Materials and Methods: In this study to supply municipal water consumption deficit of 580 Million cubic meters for three provinces of Esfahan, Yazd, and Kerman, eight practical inter-basin water transfer scenarios were selected. The scenarios transfer water from the great Karun watersheds, including Behesht-Abad, Bazoft, Khersan, and Gukan basins, to the mentioned provinces located in the Central Plateau of Iran. Four criteria, considering the proposed UNESCO criteria for the qualitative and quantitative evaluation of these projects, were assigned including technical risks and performance difficulty (C1); political and social obstacles (C2); environmental difficulties (C3); and prime cost of a cubic meter of water (C4). Upon employing three approaches of the AHP, Shannon Entropy, and DEMATEL, the criteria weights for decision making were determined. Finally, the selected eight scenarios of the study were prioritized, considering the positive and negative measures within the multi-criteria decision making, by using the COPRAS technique.
Results and Discussion: Regarding the results of the AHP method, criteria with the highest and the lowest importance were obtained as the technical risks and performance difficulty and the environmental challenges respectively. In the following, results of the DEMATEL method, considering cause and effect graphs, as well as the impact and influence of the criteria, revealed that criteria of C1, C2, and C3, got the second, fourth, and the third ranks respectively, while the C4 criterion was placed in the first rank. Also, the results showed that the former criteria, C1 to C3, were considered as cause criteria, and the latter one, C4, was an effect criterion. In the following, the weight of the criteria was computed using the Shannon Entropy method. Accordingly, the C4 criterion, including the lowest weight (Wj ) and the highest Ej value, had a common impact on the scenarios. While, the C1, with the highest weight and the lowest Ej value, was selected as the most influential and essential criterion. Then, the COPRAS technique was employed to find out the best scenario. The obtained results revealed that the 8th scenario was selected as the best scenario and the most suitable one was based on the assigned criteria. Moreover, the results showed that, except the scenarios 5 to 8 and the second one, other scenarios had various weights by using the different weighting method.
Conclusion: In this study, eight inter-basin water transfer scenarios were evaluated upon four criteria, including technical risks and performance difficulty; political and social obstacles; environmental challenges; and prime cost of a cubic meter of water. In the following, weights of the mentioned criteria were determined to employ three approaches of the AHP, Shannon Entropy, and DEMATEL, and COPRAS technique was used to prioritizing of the criteria. The obtained results revealed that 8th scenario, including water transfer from the base flow of the Behesht-Abad basin to Esfahan province, through the pumping and short water conveyance tunnel, and from the Kheran-Kersan Dam 3 to Yazd and Kerman provinces was selected as the best scenario for water transfer to central plateau of Iran. Application of the approach is recommended in complex decision making in water resources management, mostly incorporated with conflicts and inhomogeneous qualitative and quantitative criteria, due to practical utilization of this method in the evaluation and prioritizing of scenarios. It is worth noting that the proposed method was conducted in forms of fuzzy and crisp configurations.
Parisa Noorbeh; Abbas Roozbahani; Hamid Kardan Moghaddam
Abstract
Introduction: During the last decades, runoff decreasing is observed in our country as many dam reservoirs face water supply crisis even in normal periods. This decreasing trend is mainly due to the uncontrolled withdrawals, lack of supply and demand management as well as droughts. Using different flow ...
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Introduction: During the last decades, runoff decreasing is observed in our country as many dam reservoirs face water supply crisis even in normal periods. This decreasing trend is mainly due to the uncontrolled withdrawals, lack of supply and demand management as well as droughts. Using different flow prediction methods for surface water resources state analysis is important in water resources planning aspects. These methods can provide the possibility of planning for proper operation by using different factors to meet the needs of the region. Due to the stochastic nature of the hydrological processes, various models are used for prediction. Among these models, Bayesian Networks (BNs) probabilistic model has been considered by many researchers in recent years and it has shown the efficiency on these issues. Due to the growth of demand in different sectors and crises caused by drought of the water supply system that has put the basin under water stress, the water shortage has appeared in different sectors. Regarding to the strategic situation of Zayandeh Rood Dam in providing water resources for tap water, industry, agriculture and environmental water rights in Gavkhooni basin, this research presents the development of a model for prediction of Zayandeh Rood Dam annual inflow and hydrological wet and dry periods. Since the uncertainty of the predictions increase when the prediction horizon increases, this factor is the most important challenge of long-term prediction. Using Bayesian Network with reducing this uncertainty, provides the possibility of planning for water resources management, especially for optimal water allocation.
Materials and Methods: In this study for prediction of zayandeh Rood dam inflow five scenarios were defined by applying Bayesian Network Probabilistic approach. According to this, prediction of numerical annual dam inflow (scenario1), annual wet and dry hydrological periods (scenario 2, 3, 4) and range of annual inflow (scenario 5) were performed. For this purpose rainfall, runoff, snow, and discharge of transferred water to the basin from the first and the second tunnel of koohrang and Cheshmeh Langan tunnel were considered as predictor variables and the amount of Zayandeh Rood Dam inflow was selected as predictant for modeling and different conditions of input variable’s learning have been analyzed considering different patterns. Calibration and validation of the model have been done based on observed annual inflow data and the relevant predictors in scenario 1, by using SDI Hydrological drought index and long-term average of inflow to classify the runoff and clustering the other parameters in scenario 2, 3 and 4 and with classification of annual inflow data and other parameters by using clustering in scenario 5. To achieve this target, K-means method has been used for clustering and Davies-Bouldin and Silhouette Width has been used to determine optimal number of clusters.
Results and Discussion: The results of Bayesian Network modeling showed that the scenario 1 has a good potential to predict the dam inflow so that the best pattern of this scenario (considering discharge of first tunnel of Koohrang and Cheshmeh Langan tunnel, Zayandeh Rood natural inflow and rainfall with two years lag time as predictor variables), has had a correlation coefficient of 0.78 between observed and predicted dam inflow and relative error of 0.21 which shows an acceptable accuracy in prediction. Among scenarios 2, 3 and 4 for prediction of wet and dry hydrological periods, scenario 2 in which classification of runoff has been based on the long-term average, in the best pattern (with dam inflow with one-year lag predictor), is able to be predicted up to 75% accuracy. The analysis of the results showed that the scenario 5 is not very accurate in prediction of dam inflow’s range.
Conclusions: The results showed that the Bayesian Network model has a good efficiency to predict annual dam inflow numerically as well as hydrological dry and wet periods. Obtained results from prediction of hydrological dry and wet periods will be effective in better planning of water resources in order to considering possible ways of drought effect reduction. The overall results provide the possibility of water resources planning for the water authorities of this region. Systematic planning leads to optimal use of water and soil resources and helps considerably to analyze and modify the policy or rule curve of this dam for allocating water to downstream especially for agriculture and environment and industry sectors.
samin ansari; Alireza Massah Bavani; Abbas Roozbahani
Abstract
Introduction: Nowadays, the issue of climate change and its related problems are fundamental crisis in water resource management. On the other hand, considering that groundwater is the most important water resources, determination of the effects of climate change on groundwater and estimation the amount ...
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Introduction: Nowadays, the issue of climate change and its related problems are fundamental crisis in water resource management. On the other hand, considering that groundwater is the most important water resources, determination of the effects of climate change on groundwater and estimation the amount of their recharge will be necessary in the future.
Materials and Methods: In this research, to analyze the effects of climate change scenarios on groundwater resources, a case study has been applied to the Sefid Dasht Plain located in Chahar Mahal and Bakhtiari Province in Iran. One of the three Atmospheric-Ocean General Circulation Models (AOGCM) which is called HadCM3, under the emission scenarios A2 and B1 is used to predict time series of climate variables of temperature and precipitation in the future. In order to downscale the data for producing the regional climate scenarios, LARS-WG model has been applied. Also, IHACRES model is calibrated and used for simulation of rainfall - runoff with monthly temperature, precipitation and runoff data. The predicted runoff and precipitation production in future have been considered as recharge parameters in the ground water model and the effects of climate change scenarios on the ground water table has been studied. To simulate the aquifer, GMS software has been used. GMS model is calibrated in both steady and unsteady state for one year available data and verification model has been performed by using the calibration parameters for four years.
Results and Discussion: Results of T- test shows that LARS-WG model was able to simulate precipitation and temperature selected station appropriately. Calibration of IHACRES model indicated the best performance with τw=6 و f=7.7 and the results shows that IHACRES model simulated minimum amount of runoff appropriately. Although it didn’t simulate the maximum amount of runoff accurately, but its performance and Nash coefficient is acceptable. Results indicate that changes of monthly precipitation in the future period are less than the base period in both scenarios A2 and B1. Precipitation increases about 26 and 33 percent under the scenario B1 and A2 respectively in the future compared to the base period. The monthly average temperature in the future compared to monthly average temperature in the base period has been increasing in both scenarios about 1 degree. Root Mean Square Error criteria for aquifer simulation was 1.6 in steady state and 1.9 in unsteady state. This result indicates that the aquifer has been accurately simulated. Assuming the same rate of pumping wells in the future period and in the base period, despite the increasing of recharge in the future period, water levels decrease notably in the central plains due to exceeding operation. At the end of the period (year 2035) the amount of cumulative groundwater recharges in the scenario A2 compared to scenario B1 increases about 10 cubic meters per second, which shows that the impacts of climate change in the A2 scenario compared to the B1 scenario is more.
Conclusion: Study the impact of climate change is important in our country because the major uses of water supply of groundwater. Enormous use of this resource has been defected aquifer problematically. So, it is necessary to survey impacts of climate change in future period on recharge and water levels aquifer by modeling and simulation. It is useful to predict the future conditions of groundwater. Although the recharge increases in future period, but with respect to high rate of groundwater use, it is impossible to achieve an equivalent level of aquifer without any planning. We need to control on pumping well and treatment of aquifer such as underground water dam, artificial recharge and etc. results of this research can be evaluated by other climatic scenarios, downscaling models and rainfall-runoff models. The results of this research, considerably helps to assess the effects of climate change scenarios on ground water resources as well as its proper planning and management.
