مجله مدیریت آب و آبیاری
سال یازدهم شماره 4 (زمستان 1400)

Maize is one of the most important field crops in the world and Maize production with a cultivated area of about 350000 hectares and an average grain yield of 3.5 ton. ha-1 is very important and common in Iran. The purpose of this study was to investigate the effect of different levels of water and nitrogen on maize biomass, grain yield, irrigation water productivity and nitrogen productivity and finding the best irrigation and nitrogen fertilizer practices for producing Maize. Maize (SC. 704) was planted in 2018 as three irrigation treatments (I1, I2 and I3 to provide 100, 75 and 50 percent of crop evapotranspiration respectively) and four nitrogen treatments (N1, N2, N3 and N4 to provide 200, 125, 50 and zero kg of nitrogen per hectare in total, respectively) in a randomized complete block design with three replications. The results showed a significant effect of irrigation, nitrogen and their interaction effects on maize biomass and grain yield. Maximum maize biomass and grain yield were 23.02 ton. ha-1 and 12.78 kg. ha-1 for full irrigation treatment with 200 kg. ha-1 nitrogen (I1N1) treatment, respectively. Maximum irrigation water productivity for maize biomass and grain yield were 4.93 and 2.7 kg. m-3 for I2N1 and minimum irrigation water productivity for maize biomass and grain yield were 3.37 and 1.77 kg. m-3 for I1N4 treatments, respectively.

Rivers are one of the most important natural water resources in the world. Pollution transport modeling in rivers is performed by the partial advection-dispersion-reaction equation (ADRE). In the present study, using the Laplace transform, which is a powerful and useful tool in solving differential equations, the analytical solution of the ADRE equation was obtained in a finite domain with variable coefficients for the upstream and downstream Dirichlet boundary conditions and the initial zero condition in the river. To use the analytical solution in this study, three examples are presented, each of which, the river are divided into two, four, and eight parts, which, while the parameters of flow, pollution, and river geometry are variable in all three examples, for each of the examples, the accuracy of the analytical solution available when the segmentation of the intervals increases as compared to the numerical solution. By specifying the matrices of velocity, dispersion coefficient, cross-section, etc. as input to the problem, the diffusion matrix is calculated and, consequently, a complex system of equations is created that doubles the complexity of the work. The amount of pollutant concentration is calculated by solving the system of the above equations. The numerical solution is used to validate the existing analytical solution, the results showed that the greater the number of river divisions, the higher the accuracy of the solution, and the two analytical and numerical solutions will be well compatible with each other. Given the ability and performance of the existing analytical solution, it can be acknowledged that the analytical solution in this study can be used as a tool to validate and verification numerical solutions and other analytical solutions for the coefficients of the equation.

Application of compounds that improve soil moisture retention capacity is one of the strategies to increase water use efficiency in agriculture and solve the problem of water shortage. In many sources, several positive aspects of organic matter application such as biochar as soil modifier and moisture retention capacity improvement have been noted. Biochar is a carbon-rich porous compound produced by pyrolysis of natural organic matter. In the present study, 0% biochar (B1), 2.5% biochar (B2), 5% biochar (B3) and 7.5% biochar (B4), 2.5% wheat straw (W1) and 5% straw (W2) were added to soil with clay loam (S1) texture and sandy loam soil (S2). This pot experiment was performed based on a completely randomized design in three replications and in greenhouse. Biochar application increased water productivity in S1B4 and S2B4 treatments by 138% and 128%, respectively. Straw had a negative effect on agronomic yield and water productivity, so that biological yield in clay loam and sandy loam soil decreased by 82% and 73%, respectively. Water productivity decreased by 41% and 25% in S1W1 and S2W1 treatments. These reductions were statistically significant (P<0.01) and were exacerbated by increased straw in both soil types. The present study showed that biochar application can be a way to improve yield and, consequently, water productivity in agriculture.

Sediment grains size have always been considered as one of the crucial issues in the case of sediment dynamics. This seems necessary as it significantly affects sediment transport, bed roughness, and river environmental conditions. Since the geometric factors and characteristics of hydraulic flow in river bends are very complex, the analysis of sediment grain size distribution becoming an essential issue in bends that has been studied less so far. In this research, the distribution of the sizes of sediment grains in natural river bends having gravel beds was taken into consideration using field data. To achieve such a goal, 180 sedimentary samples from upper layers and other hydraulic flow parameters, including the velocity and depth of the flow and the characteristics of geometric beds, were gathered from nine different river bends. After determining the grain sizes of the sediments in the laboratory and calculating other required parameters, the P-Buckingham theory was applied to identify both the effective non-dimensional parameters and the characteristic equation. Then, the Generalized Additive Model (GAM) was used to determine the relationship between variables. Also, to avoid errors in the results, variables with a correlation coefficient greater than 0.5 and a probability value (p-value) greater than 0.05 were removed from the modeling process. Finally, a mathematical model for the distribution of sediment particle sizes based on the geometric parameters of the bends and the flow characteristics was developed. The obtained equation, with a coefficient of determination (R^2) equal to 0.76, shows that Froude Number (F_r), Shields parameter (θ_Shields), and the proportion of curvature radius to the top width section (R_c/T) affect on the median sizes of sediments in the gravel river bends.

Due to limited water resources in Iran, the optimal use of water resources and improvement of water use efficiency is necessary, especially in agriculture. In current work, cropping pattern optimization was carried out in Mehran Plain of Ilam Province based on water resources, cultivated area and biodiversity constraints using genetic algorithm. The optimization model was applied to three different scenarios based on a combination of different constraints. The results showed that the cropping pattern in 2016-17 was not optimal and the biodiversity index was low. The resulting profit and biodiversity in all scenarios are higher than the current situation in Mehran plain. The amount of profit increase in combinations one, two and three is 70, 101 and 132% higher than the profit of the existing cropping pattern, respectively, and in terms of biodiversity, the Shannon-Wiener criterion is more than twice as high as the Shannon-Wiener criterion in the existing simple cropping pattern in all scenarios. Wheat, canola, sesame and okra are strongly represented in most optimal cropping patterns. Wheat has the largest acreage and tomato and alfalfa and corn have the least acreage due to the low profit and high water consumption of these products. Crops such as corn, sesame, okra and cucumber are strongly represented in the optimal cropping patterns and can be used as alternatives to the current crops to increase agricultural profits.

One of the appropriate tools to understand the state of development in groundwater resources is to use the concept of vulnerability of groundwater resources. From a theoretical point of view, the concept of aquifer vulnerability is based on two types of special vulnerability and intrinsic vulnerability, which is defined based on hydrogeological characteristics and aquifer pollution. In this study, to assess the vulnerability of Sarkhoon aquifer in Hormozgan province, the Drastic vulnerability index was used to assess the inherent vulnerability and the GQI quality index was used to assess the specific vulnerability of the aquifer. The results of aquifer vulnerability classification showed that the intrinsic vulnerability index in the southern part of the aquifer has a high vulnerability and most of the aquifer range is in the medium vulnerability class. On the other hand, based on quality parameters in wells in the region, GQI index was measured and analyzed. The weighting of this index showed that the TDS parameter is the most important in groundwater resources. Qualitative zoning at the level of the Sarkhon aquifer indicates a decrease in the index and another expression is an increase in the concentration of solutes in the central parts and the outlet of the aquifer. Finally, by normalizing the two indicators of intrinsic aquifer vulnerability and special vulnerability, the Sarkhon aquifer vulnerability index was evaluated and calculated. Vulnerability index estimation showed that the level of vulnerability has increased in the aquifer outlet and this is also consistent with groundwater flow. In order to evaluate the accuracy of the total vulnerability index, the correlation of this index with nitrate concentration was used, which the results indicate a statistical accuracy of 72%.

In recent years, due to drought in the country, the issue of management of available water resources is extremely important, and this attention is increasingly to the management of reservoirs and forecasting the volume of water in order to provide appropriate exploitation policies. On the other hand, seasonal and excessive rainfall caused dramatic changes in the bedding of rivers and catchments, which examines the forecasting models in the event of heavy rains, which in addition to preventing damage in addition to preventing damage. Due to the occurrence of floods, surplus water can also be used in the desired direction. Therefore, not developing a proper operation policy, especially in drought conditions, can cause a lot of damage to water-consuming sectors. Proper forecasting of water flows and reservoir inventories leads to the use of control curves for the optimal use of dams and reservoir systems. In this paper, due to the importance of the subject, a model based on deep learning and Mann-Kendall experimental test was used to estimate the flood rate in the Kan-Sulqan area. The results showed that the monthly difference in flood forecast for the convolution neural network is 0.00654 and for the Men-Kendall method is 0.19532. Also, the error rates of MSE, RMSE, MAE and MPE for the neural network were equal to 0.0019, 0.0439, 0.0239, and 0.0159, respectively, which shows the high accuracy of this method in estimating the flood rate in the region.

Controlling structures in irrigation canals to accurately deliver and distribute the water, and to keep it needs the appropriate control techniques. Sarsa reinforcement learning, as a branch of artificial intelligence, has recently been used to control the structures and improve water delivery and distribution in irrigation canals. To improve Sarsa efficiency and reduce the required time of operational pattern learning, the Sarsa algorithm in the E1R1 canal was developed and linked to a non-linear model of the canal to learn the operational pattern of one reach of the canal and apply the results to the other reaches. Operational scenarios were defined in this regard, and standard performance indicators was used for assessment. The results showed that Sarsa can be used successfully with the proposed idea, maintaining water depth within a dead band of 5% in the learning step and that of 10% while utilizing the learning results. The efficiency and adequacy indicators were close to the desired value.

Climate change has many impacts on all environmental processes and society. In this study, three models selected from Coupled Model Intercomparison Project Phase 6 (CMIP6) including ACCESS-CM2, HadGEM3-GC31-LL, and NESM3 are validated. The best model (i.e. ACCESS-CM2) is selected to simulate the climatic parameters of the Sari Station using the latest emission scenarios called “shared socioeconomic pathways (SSP).” The LARS-WG is adopted for downscaling, and two emission scenarios SSP2-4.5 and SSP5-8.5 are used for two periods 2041-2060 and 2081-2100, respectively. Several statistical tests are conducted including F-test, T-student, Kolomogrov-Smirnov, coefficient of determination (R2), and root mean square error (RMSE) to validate the LARS-WG model. The verification results indicate the efficiency of the LARS-WG model. The Man-Kendal and Sen’s slope tests are adopted to determine the trend of climatic observational parameters. In general, the results show that the average temperature change increases in the range of 1.16-4.09 °C and also the average annual rainfall increases by 24-36 percent. The Sen’s slope results in terms of maximum and minimum temperatures show an ascending trend in this parameter, but it is descending in the rainfall. Since long-term climate change is one of the factors affecting groundwater and surface resources, it is necessary to develop proper management strategies for the future, preserving ecosystems, and adapting humans to these changes.

Water resources carrying capacity (WRCC) is a major component of resource and environmental studies and it is a management concept aimed at supporting sustainable socioeconomic development on a regional scale and catchment areas. Failure to pay attention to concepts such as the carrying capacity in the country's planning has led to the ineffectiveness of most programs. For this purpose, in the present study, it has been tried to use the simulation-optimization approach to determine the water resources carrying capacity in a pilot basin (Tashk-Bakhtegan Basin), considering the economic, environmental and Water resources in the historical periods (1985-2014) and terms of climate change (2045-2015) should be considered. In this regard, the Water and Soil Assessment Tool (SWAT) and the Genetic Algorithm are used. For this purpose, the outputs of three general circulation atmosphere models under RCP 2.6, 4.5, 8.5 scenarios have been used to assess climate change in this study. The results of the study indicate overloading of water resources due to increased crop area in all studied periods. Also, the water resources carrying capacity due to climate fluctuations and climate change in the examined period (1985 - 2045) has been declining, and from 2.6 billion cubic meters in the period (1985-2006) to 1.9 billion cubic meters. The most pessimistic climatic conditions are reduced.

The application of modeling is an appropriate alternative for field experiments that save time and cost. SALTMED is a generic model for modeling plants response to water and salinity stress. This study was done to evaluate the performance of SALTMED model for wheat plant in an arid area in Birjand, South Khorasan Province. The treatments include water stress (50, 75, 100 and 120 percent of water requirement) and salinity stress (1.4, 4.5 and 9.6 dS/m) in three replications. The statistical indices of measured and predicted yield showed the normalized root mean square error (NRMSE) less than 10 percent and the coefficient of determination (R2) equal to 0.99 and 0.96 for model calibration and validation, respectively. The model could also simulate the temporal variation of evapotranspiration and soil salinity profile during the growing season accurately. Therefore, according to the results, SALTMED is an accurate model to predict the yield and plant reactions of wheat under different water and salinity stress levels in the arid areas.

Drip irrigation systems are a proper technique to supply water for plants in the root zone. The management of this method relies on the science of water distribution in the volume of wet soil. Simulation models can be used to obtain this valuable knowledge. In this study, simulation of sand column in the root zone of apple tree under drip irrigation system was done to determine the optimal depth of the sand column in three various soil textures to investigate how water is uptake by the roots, water consumption, evaporation rate and deep penetration using The HYDRUS-2D model was examined. The results of this study showed that in the loam soil texture when the depth of the sand column is in the range of 10-15 cm and in the silty loam soil texture of the sand column to a depth of 5 to 10 cm, the rate of infiltration, water consumption and evaporation will be significantly less than the maximum so that the rate of deep penetration in the silty loam soil texture has decreased by 55% and in the loam soil texture by 35% compared to the maximum state. and finally, the studied scenarios showed that in sandy loam soil texture, due to the lightness of soil texture, the use of sand columns will not create an improving situation.

Limited water resources and low productivity of water consumption in agricultural sector, as the largest water consumer, necessitate performance improvement of irrigation networks. One of the necessary measures to do this is to use a systematic and comprehensive approach to evaluate and improve the performance of irrigation systems. The MASSCOTE approach is a comprehensive approach for modernizing medium to large-scale irrigation systems in terms of improving water delivery performance. MASSCOTE helps evaluate and prepare modernization programs in a step-by-step manner. In this research, the performance evaluation and improvement of Gotvand irrigation network was evaluated using the MASSCOTE approach. Based on the obtained results, the participation of users and the integration of their opinions and logical demands in the management of Gotvand Network, can be the solution to many problems. Establishment of water consumer association will reduce the problems related to water abstraction violations, and make it easier for users to access and regulate their contracts. Modifying the conventional method of water distribution, by volumetric distribution method creates a good capacity to reduce water losses and improve productivity in the network. According to the calculations, the annual supplied water, leakage and drainage of the network are 1209.5, 113.2 and 771 million cubic meters, respectively. Based on the network water balance, the evapotranspiration rate of crops was estimated at 325 million cubic meters, and the net irrigation requirement was calculated using meteorological information, was 389 million cubic meters, which is 64 million cubic meters less than the evapotranspiration rate. According to the results of MASSCOTE, in order to improve the network performance, the water balance should be improved to better maintain crop water requirement. It is recommended to change the cultivation pattern to a lower water consume pattern, and to reform the irrigation methods, and network management structure.

Khoy plain is one of the main industrial and agricultural centers in West Azerbaijan province that the water requirement for agriculture, industry and drinking water is generally supplied by groundwater. Therefore, the quality of available water seems very important in this area. Groundwater quality is generally dependent on hydrogeochemical processes that regnant the water resources system. For this purpose, in order to better understand the hydrochemical processes in Khoy plain aquifer, graphical and multi-variable statistical methods were used to interpret the results obtained from the analysis of 54 samples taken in September 2016 from groundwater resources. The results of the Piper diagram and the expanded Durov diagram shows that the groundwater type in the region is mostly calcium and magnesium carbonate, sodium chloride and the mixed type. In hierarchical cluster analysis, the samples are placed in two main clusters and five sub-clusters. The Stiff graphs identified eight general groups with saline, calcareous, basaltic, igneous and calcareous composition, Saline shale composition, shale and lime composition (Marne) and mixed type. The results of the factor analysis method suggested a three-component model for the data. In the first component, sodium, chloride, sulfate, bicarbonate, calcium and magnesium were interdependent; in the second component, nitrate and arsenic were linked; while in the third component, iron was partially related to the others. The first and third factors have geogenic sources and the second factor shows both geogenic and anthropogenic sources for groundwater contaminants.

Research on flood predicting models is one of the first steps in reducing flood damage and managing future floods in catchments. The aim of this study was to evaluate flood susceptibility in Birjand plain catchment through four machine learning models including support vector machine (SVM), J48 decision tree, random forest (RF) and Adaptive neuro fuzzy inference system (ANFIS). Therefore, in order to implement and validate the mentioned models, a list of flood-prone areas in the study area was prepared (42 flood-prone locations). In addition, 19 hydrogeological, topographical, geological and environmental criteria affecting flood occurrence in the study area were extracted to be used to predict flood susceptibility map. The results showed that the highest accuracy was related to the RF model (0.845) and the lowest accuracy was related to the SVM model (0.791). In addition, the validation of the results using the ROC curve showed that the most accurate values of flood susceptibility belong to the RF model (AUC = 0.958). The results of this study can be used to manage vulnerable areas and reduce flood damage.

Increasing water consumption along with the arid climate of Iran, has caused increasing pressure on groundwater resources and has made attention to strategic planning of water resources as a necessity. In this research, the strategic planning process of Esfarayen plain aquifer, which is one of the plains of the central desert basin of Iran, has been studied. For this purpose, a SWOT analysis was performed for the plain and its strengths, weaknesses, opportunities and threats were identified. These factors were systematically analyzed using Buckley Fuzzy Analytic Hierarchy Process (FAHP) and based on this analysis, the prior type of strategies were proposed. In SWOT analysis, five factors were identified for each group of strengths and weaknesses and seven factors were identified for each group of opportunities and threats. The results of systematic analysis of SWOT factors showed that the share of two groups of opportunities and weaknesses in higher priority factors was more than the two groups of strengths and threats, so that the share of opportunities, weaknesses, threats and strengths in the first half of the list of factors was 71, 60, 43 and 20 percent of the factors in these groups, respectively. Therefore, it is suggested that in selecting appropriate strategies for the future of groundwater in Esfarayen plain, priority should be given to WO strategies. Strategies that try to improve and eliminate weaknesses within the system by using the opportunities available in the external environment.

The use of optimization-simulation tools is one of the effective approaches that can play a significant role in analyzing water resources management scenarios. In this study, using MODSIM water resources planning model, the effect of different management scenarios in water scarcity conditions on water allocation planning in Balekhlichai river catchment and also the water level of Ardabil plain aquifer was investigated. Calibration and validation of the model were performed by considering the surface flow hydrograph of the basin outlet and the aquifer hydrograph using the data of the statistical period 2000-2014. Then the return flow coefficients were estimated by trial and error. The values of root mean square error and Nash-Sutcliffe efficiency coefficient in the calibration and validation period indicate the good performance of the model in simulating surface and groundwater flow and water balance components of catchment. After ensuring the accuracy of the model simulation, various management scenarios including population growth scenario (S), irrigation efficiency change (S1) and cultivation pattern and irrigation efficiency changes (S2) were examined. The results showed that under scenarios S, S1 and S2, the groundwater level drop will be equal to 8.41, 3.36 and 2.31 meters, respectively. Also, under scenarios S, S1 and S2, the percentage of agricultural demand supply in the Yamchi irrigation network from the reservoir will be equal to 38, 43 and 48 percent, respectively. Therefore, by applying water resources management scenarios, it is possible to prevent a sharp drop in the water level of the Ardabil plain aquifer in the future years and take an effective step in balancing groundwater.

In Iran’s sustainability puzzle, the role of human time activities, specifically in agriculture, has long been overlooked. For this reason, we applied the MuSIASEM analytical tool on Aras river basin, as a case study, in order to analyze its socio-ecological development during 2006-2016. Our results show that the biophysical pressure both on water and energy pillars. Energy metabolic rate (EMR) and Water metabolic rate (WMR) both were shifted 34%, and 21% during the decade of analysis. The household and paid work sectors both have experienced an increase of 83% and 108% in their EMR and WMR, respectively. For assessing the underlying socio-economic factor, we continued the analysis into the lower level compartments of the societal hierarchy. In agriculture, industry and service sectors, while there was a reduction of 28%, 36% and 29% in human time investments, EMR and WMR were increased by 64%, 84 and 123 for energy, and 74% and 105% for water. We conclude the result with generating composite indicators in agriculture based on the concept of metabolic processor. This shows that a crop like irrigated legume consumed 7 times more water, 9 times more land, 6 times more energy compared to fruits in one ton of their output. Also, legumes brought 37% more net added value with 5 times human time investment compared to fruits.

Improving the performance of water distribution systems in the agricultural sector is essential to increase arable crops production by considering surface water volume and energy consumption. Therefore, the main objective of the current research is to evaluate performance of practical alternatives in modernization projects in order to improve the performance of surface water distribution systems and to quantitatively evaluate their performance based on the water-food-energy nexus. The current operational management of the Rudasht Irrigation Network located in Isfahan, was simulated under normal and water shortage scenarios. Then the impact of two modernization methods including an improved manual operation and an automatic control system by using the Model Predictive Control (MPC) on the improvement of surface water distribution was investigated. In order to investigate the operational methods, eight indicators of surface water delivery, energy consumption, surface water productivity, food productivity, energy productivity, surface water economic productivity, energy economic productivity and food economic productivity were used. In the current status (Manual Method) under normal and water shortage scenarios, the values of water-food-energy nexus index were estimated 0.41 and 0.07, respectively. By improving the operational method to improved manual operation method, under normal and water shortage scenarios, the values of water-food-energy nexus index were estimated 0.46 and 0.09, respectively. The results of MPC method showed that this method has the best performance with 0.94 and 0.38 in normal and water shortage scenarios, respectively. The proposed evaluation approach can be used as an appropriate evaluation method to evaluate and prioritize modernization options of agricultural water distribution systems.

Mismanagement of shared water resources may lead to political instability, increasing the vulnerability of the social, environmental, and economic sectors, developing violent conflicts, and ultimately undermining human security. Due to its significance, various efforts and studies have been conducted to address water conflicts. “Blue peace" is one of the novel approaches that has been proposed to manage water conflicts. The main goal of "blue peace" is to apply the potential of investing in shared water resources as a way to peacebuilding. The "blue peace" approach has recently been welcomed in West Asian countries for water conflicts management. Accordingly, a comprehensive understanding of the blue peace approach and its theoretical foundations is necessary to ensure the compatibility of these foundations with the conditions governing water subsystems and hydropolitical issues in the region. It has led to the formation of the present study. Accordingly, in this study, the application of this approach in international water relations and its place in water interactions in the Middle East has been investigated by using library resources and applying an analytical approach. The results reveal that the blue peace is a reductionist approach that does not pay attention to the hidden factors affecting the water conflicts and will not lead to effective dealing with these conflicts in general as well as water conflicts in the Middle East in particular.