جستجوی مقالات مرتبط با کلیدواژه « Reliability » در نشریات گروه « آب و خاک »

Stability analysis of earthen slopes is important for the investigation of road embankments, river walls and upstream and downstream slopes of earthen dams. The sloping earthen walls of the river are always subject to instability and failure caused by various factors such as floods, variations of the water level in the river. In investigating the stability of the earthen sloping walls of rivers, the role of hydraulic and geotechnical variables and their correlations are important as factors of creating uncertainty in the analyzes. The aim of current research is to investigate the effect of water level changes on the stability of the soil slopes of the river wall under the conditions of applying the correlation of effective random geotechnical variables with the use of copula functions. Also, comparing the performance of copula functions used in combination with limit equilibrium methods is another goal of this research.

The uncertainty and correlation of the random soil properties including the internal friction angle and the cohesion of the river sloping wall were investigated at four cross-sections of Shalmanrood river in Guilan province of Iran. To this end, a computer code was developed in MATLAB and five copula functions were applied to the soil properties and the calculated correlations and distributions were compared using Akaike and Bayesian information criteria to determine the best copula. Then in GeoStudio software, using three limit equilibrium methods including Bishop, Spencer and Morgenstern-Price the slope stability was approximated. The distributions of factor of safety were obtained for three scenarios of water level including the maximum observed level and the water level decline by 20 and 40 %.

For the maximum water level in the river cross-section 1, the distribution of factor of safety was obtained in the range of 1.4-3.6 using the limit equilibrium method. By decreasing the water level by 20%, the factor of safety changes to 1.2-1.9 and declining the water level by 40% , the range is obtained 1.06-2.8. The same trends of decreasing the factor of safety by the water level decline in the river are observed in three other cross-sections. For the maximum river water level in cross-section 1, the maximum error of normal and GEV distributions were obtained equal to 7.8 and 11.4%, respectively. In addition, the error of normal and GEV distributions for water level decline by 20% were13.4% and 13.6% respectively. Finally, the error of 9% and 14.5% were obtained for the water level decline by 40% for the normal and GEV, respectively. It is observed that normal distribution offers better performance for all water levels and the errors of both distributions increase with water level decline. This trend is also observed in the all studied cross-sections.

The performance of the Morgenstern-Price method compared to other limit equilibrium methods is not affected by the variations of the water level in the river and always offers acceptable results. Three limit equilibrium methods used (Bishop, Spencer, and Morgenstern-Price) provide similar results at lower values of the factor of safety (with lower cumulative probability, CDF). Frank copula is the best function to model the correlation of random variables affecting the studied sloping walls of the river. The highest rate of change in factor of safety is observed for the water level decline by 20%.

Roof rainwater harvesting is considered an important alternative source where contaminated surface and groundwater resources are limited or not readily available. The aim of this study was to evaluate the quantity and quality of water extracted from rainwater harvesting systems for drinking water production at Sari Agricultural Sciences and Natural Resources University. To investigate the potential for rainwater harvesting within the university, one of the student dormitory buildings with a roof area of 850 m2 and a capacity of 300 students was considered. Daily rainfall data of Dasht-e Naz station in Sari in the period 2000 to 2018 were used as inputs of the water balance model to determine the appropriate volume of the rainwater storage tank. Also, in order to evaluate the quality of water collected from the roof, sampling from the roof outlet and some important physical, chemical and microbial parameters were measured. According to the results, the volume of the storage tank of 30 m3 in the dormitory with Volumetric and time reliability of 29 and 29.5 percent, respectively, was considered appropriate. The results showed that at the implementation of this system, about 309 m3 of town water consumption will be saved annually. The results also show that the direct use of collected water for drinking purposes is limited. Accordingly, according to the amount of water produced annually, it is recommended to use a UV system for disinfection and microbial purification while using a sand tank to improve physical parameters (turbidity).

 Arid and semi-arid climates prevail in Iran. The precipitation is also sparsely distributed in most areas of the country. Therefore, there is a need for management measures to overcome the water crisis. One of these measures is designing rainwater harvesting systems that can meet some of the non-potable needs and reduce runoff in urban areas. The main components of rainwater harvesting systems in residential regions include the catchment area, storage tank, and water transfer system from the catchment area to the tank. The storage tank is the biggest investment in a rainwater harvesting system, as most buildings are not equipped with a storage system. Therefore, tank capacity should be determined optimally to minimize project implementation costs. The stored water volume and the project profit increases with increasing the tank volume. However, in this case, the price of the tank increases. Therefore, the tank capacity should be optimally designed to justify economic exploitation.

 In order to evaluate the feasibility of using rainwater harvesting systems, the tanks’ volume was optimized. Due to the higher rainfall of Ardabil relative to the average rainfall of the country, it is expected that this area has a good potential for the implementation of rainwater harvesting systems. Therefore, this region was selected as the study area under the scenario of a residential house with ​​100 and 200 m2 catchment areas and four inhabitants. The amount of rainfall in the region is one of the primary parameters in determining the volume of rainwater collection tanks. Some of the precipitated water is always inaccessible due to evaporation from the surface. Nonetheless, since there is almost no sunlight during and immediately after rainfall, and also the received water enters the reservoirs shortly after precipitation, evaporation was assumed to be zero. Daily precipitation data for 42 years (from 1977 to 2019) were retrieved from the Ardabil Meteorological site. The daily water balance modeling method was used to analyze the rainwater harvesting systems due to the simplicity of interpretation, high accuracy and better general acceptance. Daily precipitation data were entered into this model and used as the primary source to meet the domestic demands. Simulation of rainwater harvesting systems was performed using daily precipitation data in MATLAB software, and the reliability of these systems was calculated for different tank volumes. Then, considering the price of drinking water and the current price of tanks in the market, the optimal volume of tanks was calculated using the Genetic Algorithm. Finally, the annual volume of water supply and the amount of water savings in case of using the optimal volumes of tanks were also estimated.

The results showed that the percentage of reliability is directly related to the volume of the tank, thus, the reliability percentage also increases with increasing the tank capacity. As the volume of the tank increases, the slope of the increasing reliability percentage decreases continuously, to the point that this slope becomes almost zero. Comparing the reliability percentage obtained for 100 and 200 m2 rooftops indicated that 200 m2 rooftop had a higher reliability percentage than 100 m2 rooftop due to receiving much more rainfall and meeting the water need for a longer duration. By comparing the results of overflow ratio for 100 and 200 m2 rooftops, it can also be concluded that using a fixed size tank, the overflow in 200 m2 rooftop is higher, which is due to receiving more water volume than 100 m2 rooftop. The results also showed that by using a 5 m3 tank, 44.5 and 24 m3 of water can be stored annually from the 200 and 100 m2 catchment areas, respectively, these are equal to 28 and 19 m3, respectively, if 1 m3 tank is used. The optimal tank volumes for 100 and 200 m3 rooftops are equal to 0.59 and 1.66 m3, respectively. Since the tanks are made in specific volumes, the obtained volumes were rounded to the closest volumes available in the market. Thus, a 1.5 m3 tank was used for a 200 m2 rooftop and a 0.5 m3 tank was applied for a 100 m2 rooftop.

Application of a tank of 0.5 m3 for the rooftop of 100 m2 was the most profitable for saving 17% of water consumption, annually. Moreover, the optimal tank volume for the 200 m2 rooftop was selected to be 1.5 m3, saving about 32 % of water consumption per year. Water-saving percentages indicate the high potential of our study area for the implementation of rainwater harvesting systems.

Population growth, increasing competition in various sectors of water consumption (industry, drinking, and agriculture), and limited water resources require the need for proper management and optimal use of water resources. Irrigation and drainage networks play an important role in the economic development of the region and the main factors of their structure change during the operation period. So that a single management program over time, can not meet the needs of the operation and this issue, reduces the efficiency of networks compared to the expected performance at the time of design. Poor performance of irrigation networks and their effect on reducing water productivity in the agricultural sector has necessitated the need to provide effective methods for the proper operation of irrigation networks. What has not regained its proper importance and status is the operation of networks in a scientific manner and under the principles of the original plan and to increase the productivity of the water consumption unit. Low irrigation efficiency reducing the useful life of irrigation facilities, increasing the costs of managing the operation and maintenance of irrigation networks, and increasing the government's financial losses are among the common problems of irrigation networks in Iran. Conventional design and operation of irrigation networks due to the lack of tools to comply with the rules of operation with the changing needs of water time, causes significant losses in the networks.For this reason, the present study was conducted to examine and determine appropriate options for managing the delivery and distribution of water in terms of space in the network.

In this regard, part of the irrigation and drainage network of Gavoshan, in the south of Kurdistan province was considered. The main channel of the network covers 2854 ha of downstream lands, which includes 9 rural cooperatives. A total of 14 intakes ranges were considered along the route, including 2 inverted siphons at the beginning of the network, 13 duckbill weir, and 23 intakes (18 farm intakes and 5 main and grade 2 intakes). 4 different operation periods were considered. 4 operation scenarios were studied based on the evaluation indices of distribution adequacy, efficiency, and reliability. To perform simulations and evaluate the performance of the main network from the perspective of operation in this study, the hydrodynamic model SOBEK, Ver. 2.12.002 was used.

According to the results obtained from the studied indicators for the S1 operation scenario (designed based on discharge at peak consumption), the average values of the adequacy, efficiency, and reliability indices were obtained 0.80, 0.96, and 0.24, respectively. in the second scenario, the average adequacy, efficiency, and reliability indicators were 0.71, 0.84, and 0.34, respectively. Accordingly, it can be concluded that for the S2 operation scenario, the distribution efficiency index for the main network was moderate and the distribution of water throughout the network based on the above index was relatively acceptable. However, the performance of the main network in water distribution based on adequacy and reliability indicators has been very poor and unfavorable, so that most of the cooperatives in the main network, have received water unequally and unfairly. According to the obtained results for the S3 operation scenario, the average values of the total indicators of adequacy, efficiency, and reliability were estimated to be 0.62, 0.71, and 0.46, respectively. Unauthorized withdrawals along the main channel were also one of the factors aggravating the decrease in evaluation indicators in different scenarios.

The results showed that the technical specifications and design of the channel are closely related to the design discharge of the channel as well as the pattern of channel operation. So that during the design, the channel should be designed based on the design discharge of the entrance to the channel, as well as the operating pattern appropriate to it. In this case, the evaluation indicators used were favorable. However, in the current conditions of the network, the technical specifications of which have not been completed and the pattern of operation and discharge of the channel do not comply with it, the lowest values were obtained for the evaluation indicators. Therefore, to improve the quality of water distribution in the network and increase the operation indicators, the technical specifications of the network should be completed and water intake should not be taken in its current form.In the current operation of the network, in addition to the problem of how to draw water from the canal and also the inflow of much less than the discharge of the channel design, unauthorized withdrawals from the canal have caused several problems of operation. In such a way that it has a direct effect on each operation indicators and minimizes them. Therefore, stopping unauthorized withdrawals from the channel in order to improve the quality of water distribution in the network is essential. It is also very important and necessary to create a mechanism to control the discharge of cooperatives located in the upstream part of the network in order to increase the indicators of adequacy and justice in the whole network.

In the present study, a multi-objective Dolphin Echolocation Algorithm (MODEA) was used to derive optimized operation rules of Gavoshan dam in kermanshah province under climate change conditions. These rules were extracted for the two purposes of minimizing vulnerability and maximizing reliability indices under the baseline i.e., April 2007 to October 2019 and climate change conditions i.e., April 2040 to October 2052. Results showed that under climate change conditions, in addition to increasing temperature by 1.8 degrees Celsius and decreasing in precipitation by 20.1%, the runoff would also be reduced to 0.69 related to the baseline period. Moreover, vulnerability changes by 18% to 45% and 10% to 39% in baseline and climate change conditions respectively, and the range of reliability changes by 52% to 89.5% and 28% to 90%, under these conditions, respectively. Comparison of the release and the water demand volume under climate change to the baseline conditions -based on the Pareto point with 80% reliability while increasing the release rate- indicates a greater adaptation of the release rate from the reservoir to the demand volume and a better performance of the reservoir under climate change conditions.

Water stored in the reservoir is one of the main sources of water supply in arid regions. Therefore, optimal operation of it is of utmost importance, especially in drought duration. In this study, optimal operation of Voshmgir dam using continues hedging policy optimized by linear programming (LP) and Partial swarm optimization Algorithm (PSO) that located in Golestan province north of Iran was investigated. The objective function is minimization of the Shortage index. In order to examine the effects of used hedging policy, 3 continuous drought years was considered. To evaluate the results of the models, evaluation criteria such as the percentage of water supply, reliability, vulnerability and stability indicators was used. The threshold volume changes per month was extracted and the base hedging rule curve for reservoir was presented. Evaluating the results of two models showed stability index in linear programming with 41.78 model was much higher than particle swarm algorithm with 6.416. Which indicates the higher performance of this model in the optimization of hedging policy in Voshmgir reservoir.

Concrete gravity dams secure their stability by the weight of the concrete used in their structure. Therefore, minimizing their weight (the volume of concrete consumed in their body) can reduce the costs significantly. This study aims to evaluate the performance of three metaheuristic optimization algorithms: harmony search, particle swarm optimization, and artificial bee colony, to find the optimal cross-section size of the gravity dam. In this way, the Koyna dam located in India is considered a case study. The programming is applied in Matlab software. Each algorithm under the constraints of this problem (the sliding, overturning, and vertical tension on the body of the dam) is run 6 times. Finally, the lowest value was chosen as the optimal result. The results revealed that however all the algorithms have the optimal outputs than their real one but the optimum one is for the harmony search algorithm. To investigate the role of available uncertainties of dam cross-section, Monte Carlo simulation is engaged. The achieved results based on reliability show more safety of dam design.

Iran is facing shortage of water resources due to the climate in which it is located. Since large areas of urban surfaces are Impenetrable streets, the volume of water harvested from these surfaces is significant and can reduce the pressure on water resources and meet a large portion of the non-potable demands, it also prevents the spread of pollution caused by overflows and backlogs in surface water collection facilities and uneconomic increase of their volumes.
In this paper, the design of rainwater harvesting system from asphalt surfaces was carried out with the aim of meeting part of the green space demand of Tarbiat Modares University faculty of agriculture, using drone images. For this purpose, available data of 22 years of daily precipitation and 761 aerial images were obtained using DJI Phantom3 Professional drone. Then, the digital elevation map of the case study was prepared and to determine the runoff direction, the basin of the area was carried out in the GIS. Reliability percentage and overflow ratios of the tanks were estimated for each level for different tank volumes. Then the optimal volume of each tank was determined using genetic algorithm.
The results showed that due to the topographic status of the faculty street surfaces, the runoff from them could not be collected in one tank, so 4 tanks A, B, C and D with optimized volumes of 6.15, 3.46, 1 and 20 cubic meters were considered in different parts of the street surfaces, respectively.
With designing rainwater harvesting systems, a significant amount of rainwater can be stored for non-potable consumption.

With increasing population and changing climate regime, water supply systems in many cities of the world are under stress. To tackle this problem, water authorities are adopting several measures including demand management and identifying alternative water sources such as stormwater harvesting, greywater and wastewater reuse and desalination. Among all the alternative water sources, stormwater harvesting perhaps has received the highest level of attention. Regarding to excessive water consumption in large cities, the problem of water shortage can be reduced to the extent desirable by using rainwater harvesting systems. “Reliability” is percentage of total days in a year when the water collected in the reservoirs is able to supply the demand of residents. “Rainwater storage potential” is the volume of runoff that is collected and used by a series of actions in the tank, before becoming a flood. The aim of this study was to estimate the reliability of rainwater storage tanks and to investigate the potential of rainwater storage. In the current study, the daily water balance between the rainfalls as input and domestic water-consumption per capita as output were used for the performance analysis and design the optimum of rainwater tanks, at three different regions of Tehran (center, north and west). These three different regions of Tehran are distinct due to notable different rainfall and topography characteristics. Charts of reliability of rainwater storage were produced for domestic rainwater tanks due to tank volume, roof area, number of people in a house (i.e. water demand) and percentage of total water demand to be satisfied by the harvested rainwater. In this study, the reliability of rainwater harvesting system was investigated for rainwater saving and non-potable water supply in three different regions of Tehran. It was found that for a relatively small roof area (100 m2), 100% reliability could not be achieved even with applying a very large tank (10,000 L). This roof area was very small to collect the appropriate amount of rainfall. In this case, the accumulated rain was used quickly and the reservoir remained empty until the next rain event occurred. For the larger reservoirs, the reliability remained constant; in which case, part of the volume of the reservoir or the entire volume remained in most of the time because the roof area for collecting rainwater was enough, or the demand for water was not high. For a large roof area (300 m2), about 40% reliability can be achieved with a tank size of 10,000 L. Reliability was independent of tank size for the sizes larger than 5000–8000 L; in these rang of size, the reliability depends on the region (location). Also, the average rainwater storage in reservoirs was determined annually for each of the three locations. The results showed that the amount of rainwater storage increases with increasing roof area. It was found that with increasing the daily water demand of building residents, the days of water supply by rainwater saving from roofs would decrease. According to the results, it can be stated that the effect of increasing the volume of the reservoir in storing rainwater for the roofs with larger areas were greater than the roofs with small areas because, the roofs with the small area do not fill the reservoir. The runoff overflow from the reservoir was often carried out on the large roofs, which can be reduced by increasing the volume of the reservoir (reducing the runoff from the reservoir and adding to the amount of rainwater stored). The maximum rainwater storage for a roof area of 300 m2 were 100 m3, annually in north of Tehran. The minimum storage for a roof area of 100 m2 were 17 m3, annually in west of Tehran. In general, the results showed that north of Tehran has more reliability and also more rainwater storage than the center and west of Tehran. The considered rainfall stations (which are located 10 to 20 km apart) produced significantly different results due to the difference in rainfall conditions and topographic variability. The results revealed that rainwater tank reliability can vary significantly within a large city like Tehran, which emphasizes the need to change the design pattern of considering a single annual rainfall value for the purpose of rainwater tank sizing.

The most important factor in the design of Chute Spillways is to control the occurrence of cavitation which is due to high velocity and negative pressure of flow. Cavitation occurs when the pressure of the fluid reaches its vapor pressure. In this condition, the fluid is evaporated and bubble is produced inside the liquid. When these bubbles arrive at a region of fluid flow with high pressure, bubbles explode and cause serious damage to structure (Iranian Water Research Institute, 2011). In Iran, the cavitation phenomenon has caused serious damage to the Karun I dam's spillway. The present study, considering the extracted results from laboratory model of chute spillway of Darian dam's spillway, investigates the probability of occurrence of cavitation and examines the reliability of this issue using FORM and Monte Carlo Simulation Method (MCSM). This model is made at a scale of 1:50 in Iranian Water Research Institute. This embankment dam is located in Paveh, Kermanshah province, Iran. The spillway channel width is 68 meters which reaches 42 meters in convergent chute. The slope length of this chute is 300.66 meters, with an angle of 14 degrees. In this laboratory model, in order to cope with the phenomenon of cavitation along the chute, two aerators in the form of deflector were used at the intervals of 211 and 270 at the beginning of chute. In order to study and control the occurrence of cavitation, it is necessary to provide information such as average velocity and pressure applied on the floor in different parts of the structure. Therefore, the flow velocity and the dynamic pressure were measured over it.

Due to population growth, shortage and severe constraints of water resources in the country, one of the main steps in management and planning of water resources is to optimize reservoirs and change the cultivation pattern. In this study, using 40 years discharge data of Kamish River and WEAP model, Hersin dam reservoir which is uder study, was simulated. Firstly, by considering different cultivated patterns, the reliability of domestic, industrial, agricultural, and environmental requirements were simulated by WEAP model and the proper crop pattern was selected on the basis of greater sustainability of the system. Then, optimization was performed by minimizing the shortages in downstream of the dam using LINGO model. According to the results, the annual average demands of environment, drip-irrigated gardens, sprinkler-irrigated lands and wastewater waterline, were estimated to be 98.98, 87.51, 89.79, and 95.63%, respectively, while these values obtained from the optimization model were 100, 99.99, 99.21, and 99.12%, respectively, which indicates that the percentage of shortcomings is less than 1%. The average overflow volume in simulation and optimization models were 7.31 and 4.09 million m3/year, respectively, which indicates that the optimization model has a lower water lost than the simulation model. Hence, by appropriate planning and management, it is possible to deduct the amount of deficits significantly, especially in the sector of agriculture.

In this research, by considering the variable-speed pump, the effect of speed on pump performance, network hydraulics and energy consumption in a water distribution network in both single-objective and multi-objective models was investigated by using the new G-JPSO algorithm. The objective function in the single-objective problem is to minimize the amount of energy consumption throughout the day, and the decision variables are the amount of pump rounds in different hours of the day and night. In the multiobjective optimization problem, the first goal was to minimize the cost of consuming energy and the second goal was to maximize the hydraulic reliability. In order to determine optimal pump operation program, an optimization-simulation model based on G-JPSO optimization algorithm was developed. In this model, the algorithm was integrated into the MATLAB environment with the hydraulic part of the EPANET model as the reference of the commands and information. The proposed model was used in the Vanzyl distribution network and the optimal exploitation instructions were extracted and the results were compared with the JPSO algorithm and the ACO. The results of the paper showed that in the single-objective problem, the G-JPSO algorithm's results are 3.28 and 0.38 percent better than JPSO and ACO, respectively. In general, the energy consumption of variable-speed pumps was lowers the constant- speed pumps. In a multi-objective problem, in all optimization scenarios, the G-JPSO algorithm was able to achieve points in comparison with the ACO algorithm, which, in addition to cost reduction, has higher reliability.

Evaporation loss is a key component of water resource management in arid and semi-arid regions where they are not uniformly distributed temporally. Also, due to the climate condition and physical characteristics of arid areas, a major part of rainfall will be out of reach in the form of flash floods and a few percent is recharged to groundwater aquifers. Rainwater harvesting system (RWHS) is considered as one of the most instrumental techniques that can save rainwater for domestic or agricultural uses. It is a technology used for collecting and storing rainwater in rooftops, land surfaces, or rock catchments using some simple techniques, such as natural and/or artificial ponds and reservoirs. In recent years, climate change has caused significant changes in the meteorological and hydrological components. Also, since precipitation is the main driver of RWHS, changes in its value and time can significantly change the operation of these systems. Therefore, in order to reach sustainable development, water resource management based on rainwater harvesting systems will be inevitable. These systems are moderately reliable methods to increase available water. The main aim of this study is the reliability assessment of rainwater harvesting systems designed for a future period (2017-2030) in Birjand, the center of Southern Khorasan Province, east of Iran.

Integrated simulation of water resources systems is an efficient tool to evaluate and adopt various options in macro-policies and decision-making procedures that are in line with the sustainable development of drainage basins. One of the drainage basin management policies is to enhance the efficiency of agricultural land use. Considering the complicated function of the drainage basin elements and their interaction with each other due to water discharge fluctuations caused by various factors such as climate change, the evaluation of these policies is of great importance. Given the low irrigation efficiency in Iran, the present study was aimed to evaluate the effects of management scenarios (including long-term irrigation efficiency increased up to 20% with 5% intervals) and discharge fluctuation scenarios (including 5% and 10% decrease in the average basin inflows) on the reliability and vulnerability of water resources system in Dez Basin. The integrated scenarios were simulated in the WEAP model. The scenarios were separately simulated for the Dez irrigation network and all farmlands across Dez Basin. According to the results, reliability was decreased by 5.69 and 18.89% in the scenarios with 5% and 10% decrease in the average basin inflows, respectively. Furthermore, the irrigation efficiency of 20% in the scenario considering the current inflows ended up with the reliability of 73.58%. Moreover, in the scenario involving 5% decrease in the average basin inflows, the reliability was increased by 3.8% with an increasing efficiency of 20%; with 3.8% and 5.7%, there was an increasing efficiency of 15% and 20% in all farmlands, respectively. In the scenario consisting of 10% decrease in average basin inflows, the reliability was increased by 1.91%, 3.8%, and 5.7% with the increasing efficiency of 10%, 15%, and 20%; on the other hand, with, these were 3.8% 9.46%, and 13.2% with increasing efficiency in all farmlands, respectively. In all scenarios, the vulnerability was found to fluctuate between 25% and 31%, which was systematically analyzed.

Background and Optimal utilization of water resources systems and the formulation of appropriate rules and policies for the exploitation of reservoirs have been considered by water resource experts in recent years and extensive research has been carried out on them. Although much progress has been made in terms of problem-solving strategies and computational tools, the problem of optimizing the operation of a multi-reservoir systems due to the effect of upstream storage capacities on low-drain inputs is so complicated. Routine optimization methods due to high constraints, discontinuous space and non-linear nature of water resource management issues are not a good tool for solving such problems. For this reason, the metaheuristic optimization algorithms have been considered by researchers. The purpose of this study was to examine and compare the results of applying GA and PSO methods in optimum utilization of Golestan and Bustan multi-grout systems in Gorgan Rood watershed using the reliability index in climate change conditions. In this research, the performance of the GA and PSO in solving the problem of optimizing the operation of a multi-reservoir system including Bostan and Golestan dams located in Gorgan-Rood watershed has been studied and compared. The survey of the entrance to the two dam reservoirs in the year 2014-2015 shows that due to the climate change, the annual input to the Bostan and Golestan dams has decreased by 17% and 60%, respectively. Genetic algorithm is a parallel and guided search based on the theory of evolution. The operators of the GA algorithm include selection, crossover, and mutations that are used up to the next generation, respectively. In PSO optimization algorithm, based on the birds and fishes movements, a number of particles are propagated in the search space and the value of the objective function is calculated in proportion to the position of each particle. Then the new particle position is calculated using the combination of current particle locations and the best place previously used. Achievements: The best answer of the PSO algorithm during the 10 runs is 909.95 and the worst is the equal to 930.53, while the best answer of the GA algorithm during the 10 run is 931.17 and the worst It was 957.32. The comparison of the mean of the answers also show that the PSO algorithm has a 3% advantage over GA. The PSO algorithm has a better performance than GA, so that the PSO algorithm with a reliability of 49.38% has a better performance than the GA algorithm with a reliability of 48.44%.

One of the most important issues in water resources management, is the optimal operation of dam reservoirs. In this research metaheuristic invasive weed optimization algorithm was used to find optimal water allocation strategies for a period of 10 years in Tazeran dam that located in the west of Iran. The developed model in this research is provided for optimal operation in the present state of cropping pattern. The downstream field of Tazeran dam are divided into two zones consist of Tazeran and Evandeh. The defined objective function is to minimize total deficiencies during the simulation period. In order to investigate the reservoir performance indicators of time reliability, percentage to provide volume and vulnerability is used. The results of IWO algorithm also compared with the results of the Genetic algorithm method. Due to the inadequate and inappropriate distribution of Tazeran river flow, simulations have been done in two states, use of surface water flows alone and the combination of surface and underground water flow. Result shows that using IWO and GA method and use of surface and ground water simultaneously, Tazeran dam is able to provide 77.2% and 76.24% of the total downstream of water requirement. Also, reliability and vulnerability indicators in Tazeran region are 55.45% and 33%, respectively, in the IWO method and 52.72% and 41% in the GA method.

Optimal operation of dam reservoirs is important due to their role in runoff control and water supply for different sectors. In this study, the Firefly Algorithm (FA) is investigated to solve the problem of optimal operation of Haraz dam reservoir to provide water for agriculture, drinking, industry and environmental of downstream for a period of 27 years (since 1984 to 2011). The objective function was defined as minimizing the sum of squared monthly relative deficiencies during operation. The efficiency of these algorithms was compared and evaluated by determination of reservoir performance indices, the value of objective function, annual deficit, monthly average deficit and release. FA method with reliability of 88.3 percent is supplied the downstream demands better than GA and SOP with reliability of 82.4 and 66.7 percent. The Vulnerability index of models is obtained 0.20, 0.23 and 0.99, respectively. The results showed the better performance of FA algorithm compared to the other two methods in solving the problem of the reservoir operation.

Groundwater is predominantly a renewable resource, and when managed properly can ensure a long-term water supply for increasing water demand and for climate change impacted region. Surface water renews as part of the hydrologic cycle in an average time period ranging from approximately 16 days (rivers) to 17 years (lakes and reservoirs); however, the average renewal time for groundwater is approximately 1400 years for aquifers to millions years for some deep fossil groundwater. Groundwater depletion, which is the reduction in the volume of groundwater storage, can lead to land subsidence, negative impacts on water supply, reduction in surface water flow and spring discharges, and loss of wetlands. Water balancing strategy has been considered as one of the most effective options to mitigate the groundwater depletion, and thus the balancing scenarios are applied as main approach to manage ground water sustainably. The purpose of the water balancing strategy in aquifers management is that groundwater level to be returned to the primary water level and to compensate the water resources shortage of aquifers’ storage.
1. Case study: Birjand aquifer with an area of 1100 square kilometers is situated in eastern part of Iran. The location of the aquifer is between 59o 45 and 58o 43 east longitude, and 33o 08 and 32o 34 north latitude.
2. Modeling: Laplace Equation is the basic equation for groundwater flow study in steady or unsteady states. In simulation by using numerical models, the boundary of the model, recharge and discharge resources, evaporation and recharge zones are important elements. After finding the key components of the conceptual model, the MODFLOW software was applied for simulation of groundwater. MODFLOW, which is a computer code that solves the groundwater flow equation and uses finite-difference method, is provided by the U.S. Geological Survey.
3. Sustainability Analysis: In order to achieve the objective of this study, water balancing scenarios should be evaluated for sustainability of the groundwater system using appropriate indices. Here, three indicators of reliability, vulnerability and desirability are proposed and were employed to assess the stability of groundwater system in different balancing scenarios in lumped and distributed forms. The aquifer sustainability index is expressed in Equation 4. In this equation, three indicators of aquifer reliability (Equation 1), aquifer vulnerability (Equation 2) and Desirability (Equation 3) have been used to assess the stability of groundwater system. The aquifer reliability index means in what extent the withdrawal scenario has been able to return the aquifer to its original state using the Equation 1 as follows:(1)
In which the number of periods where the groundwater level is above the desired level (equilibrium balance) and the total number of time steps in simulation. The vulnerability index indicates the amount of shortage in the groundwater storage and expresses the severity of the system failures using the Equation 2 as follows:(2)
In this equation, the desired groundwater level at time step t, the groundwater level simulated in t time period for each scenario, the groundwater level without scenarios and n the number of periods where the groundwater level is lower than the desired level. The index of the likelihood of returning the system to a favorable state is presented as an indicator of the desirability of the system using the Equation 3 as follows:.
(3)
In this equation, indicates the f ground water level after the depletion, is the desired level of groundwater and is the groundwater level (without the scenario). After estimating three indicators of reliability, vulnerability and desirability, the sustainability index for each scenario can be appraised using Equation 4.
(4)
In this equation, groundwater sustainability index, reliability index, desirability index and vulnerability index.
In this study, six water balancing strategies were employed to reduce 1, 1.5, 2, 2.5, 3 and 3.5 percent water withdrawing for agricultural water use. Results of the simulation of different water balancing strategies demonstrated that with reducing in water use, the stability index has been improved significantly. The improvement changes from 32% increase in the index for 1% water withdrawing reduction scenario to 88% increase in the index for the 3.5% water withdrawing reduction scenario. Moreover, the reviewing of the stability indices of the system in various scenarios reveals that a 2.5% reduction in water use will assistance the aquifer status achieve to a stable state.
In order to manage groundwater withdrawal, it is easier to assess the impact of the water balancing scenarios using the groundwater sustainability index. The review of sustainability indices in the studied aquifer shows that by reducing 1% of the water harvest, 32% of the system's stability increases, and if water harvest reduction reaches 3.5%, the index increases 88%. Considering the distributed potential and possibility of the investigation of different scenarios by proposed indices in this study, they can be applied to assess and manage other similar aquifers.

In this study, a method is proposed by using a multi-objective structure and employing new formulations, in which instead of increasing reliability based on meeting a demand of 100 percent in some months regardless of the dry months, part of the water of wet months or seasons is stored in reservoirs so that it can be used in dry months in order to amend failure intensity. To this end, Multi-Objective Particle Swarm Optimization (MOPSO) algorithm was connected to the WEAP simulation model. The main purpose of this type of structures is to offer a resolution to increase the percentage of demand coverage in dry months in addition to reaching to an acceptable demand meeting reliability over the entire period considering the operation capacity of the reservoir. Ultimately, the results of three scenarios, including a current situation, land development management scenario and an optimization one, were evaluated. According to the results of the current situation scenario, in all of the operation period the situation was reported acceptable, except for a few months. In land development scenario, for most consumptions in most of the dry years and in the last six years of planning, the demand coverage was equal to zero in three to eight consecutive dry months, and it was lower than 5% in these months in the rest of the low-water years. On the other hand, the demand coverage increased from 28% to 60% in these months by implementing the optimization model. Also, in the optimal scenario of reliability, supplying downstream environmental demand and Maroon hydroelectric dam need was improved. This study depicts that using the strategies of this research will lead to a better reservoir management and will reduce failure intensity in supplying different consumptions during low-water months.

Drinking water supply to Larestan region in Fars, Iran, is fulfilled from Salman-Farsi Dam, which is not reliable all the times due to drought and presence of other stakeholders. On the other hand, there are many well fields available to Fars Water and Wastewater Company with varying discharge capacity and total dissolved solids concentration. Optimum mix of the trensfered water from well-fields’ pumping and the transferred one from the dam by the pipeline is the main question of the decision makers for maximizing the reliability of the drinking water while fulfilling the water quality constraints. Therefore, conjunctive use of dam’s release and pumping is selected as managerial approach to be optimized under water quality constraints with the target of maximum drinking water supply to demands. The conjunctive use of the water released from dam and withdrawn from the wells is a candid strategy selected by the decision makers among many other strategies for water supply in the region. The conjunctive water use model is formulated in GAMS environment and solved by nonlinear optimization solver MINOS. The conjunctive water use strategy is planned and optimized for three stages of short-term, mid-term and long-term Operation, and operation rules for dam’s release and pumping rates are presented. Current midterm water supply reliability from dam is 63% while with conjunctive use it becomes 90%. In emergency cases (malfunctioning of water transfer system) the reliability without conjunctive water use is 49% while conjunctive water use increases it to 77%.