Journal of Water and Soil Conservation
Year:2019 | Volume:26 | Issue:4 |Papers Count:19

Background and Objectives: Rivers discharge variations, variable rainfall regimes and drought are important reasons for using the water resource management tools in multi reservoir operation. Heuristic optimization methods can be used with different fitness functions; they can be applied for a wide range of water resource management problems specially reservoirs operation systems. Gravitational search algorithm (GSA) is an evolutionary optimization algorithm based on the law of gravity and mass interactions. In this paper, the ability of this algorithm is investigated for solving the well-known benchmark functions, hydropower-reservoir and ten-reservoir operation system. Materials and Methods: For the verification of new evolutionary algorithm, three well-known benchmarks of Bukin6, Rosenbrock, and Sphere were optimized with gravity search algorithm and the results were compared with the outcome of well-developed genetic algorithm (GA) and global optima solutions. Then, hydropower-reservoir operation of Karon4 reservoir was optimized with GSA and compared with the results of GA and global solutions. The global solution was obtained from linear programing solving method by using Lingo software. Finally, the ability of GSA was investigated in large scale water resource management problems. In this regard a ten-reservoir system operation was optimized with both GSA and GA and their results were compared with the global solution. It should be noted that the results were reported in different ten runs for three types of problems to ensure that the results are true. Also the function evaluation values of GSA and GA were equal for all optimization problems. Results: The ability of GSA in optimizing of different types of problems are demonstrated with showing the solving results of well-known benchmark functions. The results of Bukin6, Rosenbrock and Sphere problems were close to global optima solutions compared with the outcome of the welldeveloped genetic algorithm results (GA). In single-reservoir hydropower operation, the average values of the objective function were equal 1. 218 and 1. 746 with the GSA and GA, respectively. The global solution equals to 1. 213. Over all, the mean optimum solutions in GSA are better than that of obtained for GA in hydropower-reservoir and ten-reservoir operation problems about 44% and 8% respectively. Conclusion: The results demonstrated the applicability and efficiency of the proposed algorithm in solving the well-known benchmark functions and water-resource optimization problems such as hydropower-reservoir and ten-reservoir operation systems. It is indicated that GSA solutions in different runs are close to the global optima and the algorithm is converged more rapidly than the genetic algorithm.

Background and Objectives: Rivers have always been transformed in their evolutionary path by the erosion of the beaches and river bends as well as sedimentation in other parts that is an unnecessary change for the inhabitants of the rivers. Submerged vanes technique has been used for strengthening river bed, protection of river banks, decreasing erosion in the river bend, preventing penetration of river bed sediments to intake structures, correcting river cross section in the adjacent bridge bases. In the present research using an experimental model by changing different parameters related to submerged vanes, the way of transferring bed load was examined in a separate section. Materials and Methods: The objective of this research is examination of the effect of submerged vanes on load convey in a separate section. For this purpose, the middle part of the flume was considered for creating separated and broadened sections. From the beginning of the flume 0. 7 m with original width of the flume was considered as slowing down current for establishing a uniform current. After that, two glass boxes with 4 m length, 0. 075 m width were used for decreasing flume width in higher part of the experimental cross section. Then, 1. 5 m length with original width of flume was considered as experimental cross section. From the end of the experimental section to the end of the flume, the conditions of the upstream canal were repeated. After finishing experiment, the rate of sediment progression is recorded in experimental section. Also, after finishing experiment, the experimental section is drained and using laser meter device in a 5×3 matrix, the topography of the sediments in experimental section is set. In these experiments, dimensions, angle, arrangement and length distance of submerged vanes change and its effect on vane performance were examined. Results: Examining the effect of vane dimensions on the transfer bed load, indicated that by increasing submerged vane dimensions, submerged vane performance parameter is also increased; in such a way that. it increased from 10 to 46 percent with increasing the dimensionless length from 0. 19 to 0. 38 in dimensionless height of 0. 31. By increasing the ratio of the dimensionless length, the width distance between vanes is decreased and causes increase in effect domain of whirling currents and this causes whirling movement of sediments around submerged vanes and not forming sediment beds. This causes dispersion and accumulation of sediments around submerged plane and decreases the speed of transferring bed load. For detecting vane performance in different arrangements, eight experiments were conducted. submerged vane performance parameter was higher than zero in all arrangements indicates decreasing bed load transfer and also decreasing bed load progression distance in experimental cross section relation to the observing state. The more number of vanes in Z and parallel arrangement and influence of vortex flows cause that sediment transport velocity is decreased. Generally, experiment parameter varies between 7 to 25 percent. For detecting the effect of installation angle on submerged vanes performance, experiments included six angles. The results indicated that all of the installation angles have positive performance and the submerged vanes in 90 degrees in relation to approaching current showed the highest performance than other installation angles of submerged vanes that was 23 percent. Conclusions: In general, we can conclude that installation of submerged vanes in experimental phase causes change in progression velocity of sediments and change in sediment distribution pattern. Also the results indicated that increasing dimensions of submerged vanes causes decrease of sediment transfer and increase of sediment accumulation around the first row vanes. According to the results of arrangements, in convergent arrangement with 30 degrees to approaching current, the submerged vanes indicated the best performance. Also, the chess arrangement does not have a satisfactory performance due to the relatively width distance in double rows of the vanes.

Background and Objectives: One of the main issues in water quality management is the determination of thermal layering followed by nutritional levels in reservoirs of dams and other water structures. Determination of thermal stratification is done using qualitative models. To select a water quality model, there should be an exchange between the complexity of the model, the reliability, the cost of operation and the time available. Determining the parameters of a nutritional index such as total phosphorus and total nitrogen concentration in the lake, the average and maximum chlorophyll a concentration, and the amount of dry algae using these equations requires the least qualitative data and less time and cost compared to complicated computer modeling. In the current study, water quality of Mahabad dam reservoir located in West Azarbaijan province was investigated using CE-QUAL-W2 model, which is an efficient software for the analysis and qualitative analysis of water reservoirs and lakes. According to the results, the Mahabad Dam reservoir has a roughly strong summer stratification, which begins in late April and reaches its peak in August, with the onset of autumn and a decrease in the amount of incoming radiation to the stratified reservoir, leads to mixing so that in December, the complete mixing takes place in the reservoir. In terms of the Total Soluble Solids (TDS) level, it can be stated that the trend towards depth changes is rising, so that the maximum concentration is throughout the year at the bottom of the reservoir. The changes in dissolved oxygen relative to the depth of water in the reservoir are also reducing; these changes start from June and continue until last summer so that the concentration of dissolved oxygen in the substrate reaches zero during this time of year, which eventually produces unpleasant color and odor in the reservoir. Materials and Methods: Mahabad storage dam is a dike dam on the Mahabad River, west of Mahabad city in the West Azerbaijan province. Mahabad Dam has a trifling capacity of 197 million cubic meters and 172 million cubic meters of useful capacity. In addition to supplying drinking water to Mahabad, more than 12 thousand hectares of agricultural land in the city are under its coverage. The dam also has a hydroelectric power plant. Construction began in 1968 and the dam was completed in 1970. In this research, a two-dimensional CE-QUAL-W2 model was used to simulate nutritional (eutrophic) in Mahabad Dam. Then, the geometry of Mahabad Dam reservoir was introduced to the model. For this purpose, it was produced cross-sectional profiles along the reservoir's line at specified intervals and obtained information by measuring the profiles at depths of two meters using the topographic maps of the dam reservoir and the AUTOCAD software, collecting data entered to depth gauge. To investigate the sensitivity analysis, the following items were used: 1. Windscreen coefficient (WSC) 2. Light-to-water penetration coefficient (EXH2O) 3. Temperature Sedimentation Coefficient (TSED) 4. Solar absorption coefficient (BETA) 5. Viscosity coefficient of vortex Horizontal (AX); Horizontal Swing Diffuser (DX); Friction Coating Friction (FRICC). Results: The results were summarized as follows after the accomplished research. The coefficient of wind cover during the layering process has a significant effect on the temperature variations in the sublayer. As the wind influences on the lake, thermal inequality moves toward mixing. During the complete mixing of the reservoir with an increasing coefficient, the temperature of the water decreases to 4 degrees Celsius. But, the effect of this parameter during the mixing of the reservoir is not significant. The thermal difference between sublayer and the top layer is 2 to 3 degrees Celsius. Since the mixing season occurs in cold seasons from year to year, so the light, the high parameter will not affect the increase in reservoir water temperature. Therefore, the effect of the parameter can be ignored during the mixing phase. As the BETA coefficient increases, the reservoir flows goes toward mixing. Since this coefficient does not place a noticeable error in the thermal profile. The results of calibration of the model with respect to the thermal profile show that applying suitable coefficients for sensitive and effective parameters can be used to better the environmental conditions governing the region, including hydrological, hydraulic and meteorological conditions effective into the software environment. It is effective and can play a significant role in the better implementation of output and observational data. With the escalation of thermal layering, salinity layering also occurs, and the peak of this layer occurs simultaneously with the thermal layering in August, and after that, as the summer progressively decreases the degree of salinity and ultimately the reservoir will be fully mixed in terms of salinity in the first autumn. Conclusion: In this study, the CE-QUAL-W2 model was used to simulate the eutrophication in Mahabad Dam reservoir. The results show that the reservoir of Mahabad Dam has a summer layering cycle, so that by end April, with increasing air temperature, the thermal layers were gradually found in the reservoir and peaked in the middle of summer. By passing the summer season and entering the cold seasons, the layered formation is gradually adjusted so that it occurs completely in the reservoir in December. Mahabad Dam is located in a cold climate so that winter temperatures fall below 4 ° C. Therefore, winter layering (inverse layering) is expected to occur in the reservoir. Also, the amount of variation in concentration (TDS) at depth is influenced by the thermal layering in the reservoir and the process of its variation is the reversal of temperature variations. The concentration of dissolved oxygen in water (DO) is also expected to decrease as the depth increases during layering.

Background and Objectives: The most distinguished effect of dams is change in the hydrologic regime of its downstream areas, which can be attributed to permanent supply flow and changes in the level of groundwater. The assessment of groundwater level changes is an important issue in analyzing hydrogeological time series of aquifers. Considering the different performance of effective factors in budget and hydrology in the catchment area of ShahreChay plain, it is necessary to review the trend analysis, which is complicated. Investigating temporal and spatial variations of groundwater levels in planning and managing sustainable water resources in arid and semi-arid regions is very importance. The purpose of this study was to evaluate the changes in trend of groundwater level of the aquifer piezometers in the ShahrChahi before and after the construction of the reservoir with the use of nonparametric methods of Mann-Kendal, the Sen's slope, Pattit, Boishand and comparind with the result of the MODFLOW software. Materials and Methods: The methodology of this research was based on library, field, and statistical methods. In this study, 10 stations in ShahreChay aquifer were used to study the groundwater level changes from 15 years (1381-1396). Ground water level trend at all stations were evaluated annually and at minimum and maximum water levels of the aquifer. The groundwater model is provided using the Modflow code in the GMS software. In order to investigate the longitudinal groundwater slope changes, the Kriging method was used in GIS 10. 5 software. Results: The researches show that the trend of ground water level changes in the 80% of piezometers was negative and a failure occurred in the time series in 2007-2008. At the stations closer to ShahrChay Dam, it is usually the year of jumping from 2007 to 2008. It is usually the year of jumping after 2007, 2008, or 2009 at far and near the riverside and far off the rivers. In Modflow software, with using piezometric wells and other studies to predict the level of groundwater level in the stable state of the dam calibration and prediction was performed. Data from June 2002 were used to prepare the model in a steady state Modflow software was used to predict the level of groundwater level in the steady state of the dam calibration and prediction. For the years 2003 to 2005, groundwater level was predicted with less error. Continuing calculations, the groundwater level of observation by 2017 is less than predicted. Also, the study of changes in 15 years isopotential lines indicates a decrease in the slope of the basin due to the lack of nutrition due to the construction of the dam. Conclusion: The results show the effect of reducing the surface water level caused by the dam construction. One of the reasons is the water storage in the dam at flood time. How to use the stored water in the crop season conditions that are directly used before construction the dam the flood distributed in area and causes an increase in the level of ground water that construction dam haven't been caused the recharge in the groundwater.

Background and Objectives: Base flow is an important component of flow hydrograph, which feeds by ground water or shallow subsurface flow, Sub surface flow and plays an important role in ecological function of a river. Identification of base flow contribution provides a basis to assess the watershed response and information on base flow availability and contributions is needed to develop water quantity and water quality management strategies in watershed scale. Also, the separation of the base of the important factors in hydrologic modeling and increase the accuracy of the model calibration in rainfall-runoff prediction. Comparison of different watersheds based on flow recession and low flow components can provide useful information regarding the storage characteristics and flow recharge. Also, the base flow contribution amount can be used in the analysis of environmental flow assessment and river flow health condition. Base flow component strongly affected by flow extraction through the flood plain wells which can be a source of uncertainty in the base flow separation by well-known numerical methods. The aim of this study was to compare graphically and recursive digital filtering techniques in base flow separation and selection of appropriate methods to estimate the base flow contribution in number of rivers over Ardebil Province. Materials and Methods: The base flow was estimated on daily basis using three graphical methods, including, 1) Fixed time interval, 2) Sliding time interval, 3) Local minima and six recursive digital filters including, 1) One-parameter algorithm, 2) Bughton two-parameter algorithm, 3) IHACRES three parameter method, 4) Lynne and Hollick, 5) Chapman algorithm and 6) Exponentially Weighted Moving Average methods. The results of these methods were compared with the recession analysis method as a reference. Estimated and analysis the results of base flow methods were compared for a 22-year period (1989-2011) for which stream flow data were available in 5 river gauge station in different ranges of flow rates over Ardabil Province. Results: According to the results and the comparison of graphical and filtering methods of base flow separation, it was found that the accuracy of graphical methods is not acceptable (with negative and less than unity values) according to Nash-Sutcliffe efficiency criteria. Accordingly, the performance of Fixed time interval method according to Nash-Sutcliffe efficiency criteria-0. 04 did not give a good result in the study area. While, Two-parameter Boughton and Oneparameter algorithms are most suitable methods in estimating the base flow component of hydrograph with 0. 88 and 0. 86 efficiency criteria respectively in the study area. Conclusion: The results showed that graphical methods had not satisfactory results, but the digital filtering techniques based on signal processing theory had high accuracy in separating the flow hydrograph to speed and delayed components. The estimated base flow hydrographs by recursive digital filter methods showed good agreement overall with the recession analysis method. As a concluding remark, the recursive digital filters are more suitable methods in the study area with nonlinear nature complying the sequence of discharge data time series with respect to linear graphical methods. The suggested appropriate methods can be used to low flow regional analysis, hydrologic modelling and determination of the base flow contribution in daily flow hydrograph data in the study region.

Background and Objectives: Drought is one of the most complex and dangerous natural disasters that changes both in space and time. Global warming has intensified such extreme events in recent years. Thus, the use of drought indices that consider both the effects of precipitation and temperature, as well as the use of joint spatio-temporal methods, which are the extensions of spatial statistics, can probably lead to better drought monitoring and thereby increasing the accuracy of predictions. The data correlation structure is determined by the spatio-temporal covariance functions in these methods. The aim of this study is to use and compare a number of spatio-temporal variograms for predicting and spatio-temporal mapping of drought by using the 12-month SPEI index. Materials and Methods: In this research, the monthly rainfall and temperature data of 48 stations in the northeast of Iran during the statistical period of 1981-2012 were used to calculate the SPEI index in a 12-month time scale. The exploratory analysis of the data was studied in terms of stationarity and isotropy assumptions. The data were divided into two groups of training and experimental data of 2012. The separable, metric, sum-metric and product-sum spatio-temporal covariance functions were fitted to determine the best combination of spherical, linear and exponential variograms for each of the spatial and temporal variograms on training data. The best model was selected using the MSE and MSPE statistical criteria, and the required parameters were estimated. Finally, using spatio-temporal kriging, the experimental data were predicted, mapped, and compared with the map of the observed values. Cross-validation of spatio-temporal and purely spatial models was done via COR, ME, MAE and RMSE statistical criteria by using 25 and 47 neighborhoods. Results: The test of the stationary of spatio-temporal data showed the spatial stationary. Drawing of the average time series data showed a decreasing trend, which was modeled by a simple regression with the use of SPEI index values as dependent variable and time as an explanatory variable, and the data were detrended. The spatial variogram in four directions of 0° , 45° , 90° and 135° did not show a significant difference between the four variograms and the assumption of isotropy was therefore accepted. The separable, metric, sum-metric and productsum models were used to determine the correlation structure of data. The comparison of models by means of MSE criteria showed that product-sum and sum-metric models have less error as compared with the other two models. Comparison of these two models in the prediction of unobserved values selected the product-sum model as the better model with the linear variogram for both the space and time via the MSPE criteria. After estimating the model parameters and using spatio-temporal kriging, the SPEI values were predicted for the experimental data and their spatio-temporal maps were plotted. The similarity of the map of the predicted values and that of observed values indicated the good performance of the model in predicting the unobserved values. Cross-validation of spatio-temporal and purely spatial models also showed that the performances of various models were very close to each other. Conclusion: The results of this study showed that the product-sum spatio-temporal covariance model has a good ability to predict the unobserved values as compared to other models, and with the aid of these models, the values of the desired variable can be predicted in any spatial location and at any time scale. Also, cross-validation of the models showed that the different spatio-temporal and purely spatial models do not differ significantly from one another, and the precision of the models have not increased as compared to the purely spatial state.

Background and Objectives: In the recent years, increase of temperature due to increase of greenhouse gases have led to anomaly in the Earth climate system. Due to the importance of climate change and its effects, and in order to plan for adaptation to climatic variations, prediction of atmospheric variables have been done by scientists using different models. The objectives of this study were to analyze the annual rainfall and temperature trends, compare the results of fifth report of Intergovernmental panel with each other and determining the changes in rainfall and temperature in future periods compared to the base period at the annual and monthly scale, and estimated water requirement of date palm in Ahwaz area. Materials and Methods: In this research, downscaling method was done using SDSM model by using fifth report of Intergovernmental panel on climate change (IPCC) under new emission scenarios. Climate Change models under new three models scenarios namely RCP2. 6, RCP4. 5 and RCP8. 5 under three future periods: near-century (2010-2040), mid-century (2041-2070) and latecentury (2071-2099) were investigated and compared for Ahwaz station. Daily rainfall observations, average, minimum, and maximum temperatures for the period 1966-2001 were inputs of model. Results: The results of the output of the downscaling methods showed that in the future periods, based on the all three studied scenarios, the temperature increase and precipitation will decrease in Ahvaz station. In the different scenarios, the lowest temperature rise will be in June with 0. 95 degrees Celsius under RCP 8. 5 and the highest temperature rise in September will be 3. 96 degrees Celsius under RCP 4. 5 during 2011-2040. The lowest average annual temperature rise will be 1. 96 degrees Celsius under RCP 8. 5 scenario and the highest average annual temperature rise was 2. 57 degree Celsius under RCP 4. 5 during 2011-2040. The lowest temperature rise in December will be 3. 13 degrees Celsius under RCP 2. 6 and the highest temperature rise in September with 5. 57 degrees Celsius under RCP 4. 5 during 2041-2070. The lowest average annual temperature rise will be 3. 18 degrees Celsius under RCP 2. 6 scenario and the highest average annual temperature rise will be 4. 65 degree Celsius under RCP 8. 5 during 2041-2070. The lowest temperature rise will occur in January with 1. 58 degrees Celsius under RCP 2. 6 and the highest temperature rise in September with 6. 62 degrees Celsius under RCP 8. 5 during 2071-2099. The lowest average annual temperature rise will be 4. 27 degrees Celsius under RCP 2. 6 scenario and the highest average annual temperature rise will be 5. 99 degree Celsius under RCP 8. 5 during 2071-2099. The results of water requirement using CropWat 8 software showed that the required water content in the period 2040-2011 in the scenario (RCP2. 6) would decrease by 0. 4 and increase 5-8% under two other scenarios. The required water requirement for 2041-2070 showed 15-19% increase and for 2071-2099 showed 25-28% increase. Conclusion: Due to the increase in temperature and the decrease in rainfall during the upcoming periods, the water requirement for Date palm will increase in Ahwaz region.

Background and Objectives: Drought stress is the most important environmental factor limiting the growth and development of plants around the world, as growth retardation due to drought stress is reported more than other environmental stresses. Sesame due to its resistance to drought and heat is of great importance in the development of agriculture in arid and semi arid regions during summer planting. The purpose of this research was to investigate the effect of drought stress by applying different levels of T-Tape drip irrigation and identification of superior cultivar based on stress indices. Materials and Methods: In order to study and evaluate drought stress indices in drip irrigation method, yield, grain yield components, oil yield, seed oil percentage and grain water use efficiency were tested in 2018-2019 in Behbahan Agricultural Research Station. The experiment was conducted as split plots in randomized complete block design with 3 replications. The main factor included water levels in drip irrigation at four levels of 40, 60, 80 and 100% of water requirement from the beginning of flowering stage and the sub factor including varieties in two levels including local of Behbahan and Shevin. For comparing the results of the measured and calculated results, Pearson correlation coefficients were used for all measured or calculated parameters. Results: Comparison of the average water use efficiency of irrigation and cultivar interactions showed that 100% water requirement and local Behbahan cultivar with water use efficiency of 0. 222 kg/m3 of sesame seeds were superior treatments. Average water consumption in one year of experiment in 40, 60, 80, 100% water requirement and control (surface irrigation) treatments were 0. 35, 41. 4, 47. 8, 54. 2 and 65. 1, respectively. The results of Pearson correlation coefficient showed the highest correlation of 1000 grain weight with 0. 9305 with grain yield index, which indicates the effective role of 1000 seed weight gain in increasing grain yield. Due to the high values of stress sensitivity (SSI) and tolerance (TOL) values in the local cultivar Behbahan compared to the Chevine cultivar and also the low rates of STI, MP, GMP, HM, YI and YSI indices in Behbahan's local cultivar compared with Shevin, Behbahan's local cultivar can as the best treatment for drought stress. Conclusion: Increasing plant height significantly correlated with increasing the number of seeds per capsule. The most significant correlation between number of seeds per capsule, as one of the important components of yield with plant height and plant height, with consumed water volume shows the important role of optimum management of deficit irrigation in sesame crop. The yield under tension of local Behbahan sesame variety was closer to Shevin cultivar than non-stressed yield and this factor was effective in increasing the TOL index in local Behbahan sesame variety relative to Shevin. A variety of Sesame can be considered as resistant to drought stress that its TOL index correlation coefficient is more negative. The identical trend of changes in the MP index led to the introduction of this index of the most insensitive stress index and the TOL index as the most resilient indicator for stress variations. The TOL index classifies the two investigated varieties sesame according to their performance variations. The lower the variation, the sesame variety will show more stability under stress conditions.

Background and Objectives: Nowadays, the necessity of dealing with strategic agricultural production such as wheat in stressful environments is an indispensable necessity for achieving maximum potential for food supply. Fluorescent Pseudomonads bacteria are one of the most important group of beneficial soil rhizobacteria that increase the yield of plants with numerous growth-promoting properties Materials and Methods: This research was carried out to screen 15 Fluorescent Pseudomonads isolates, isolated from rhizosphere soil of dry farming wheat, in terms of PGP traits such as 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, indole-3-acetic acid (IAA), Siderophore, solubilization of inorganic insoluble phosphates (Tricalcium phosphate: TCP) and hydrogen cyanide (HCN) (under non-saline and saline conditions), salinity resistance, drought resistance using polyethylene glycol (PEG 6000) (with osmotic potentials of-5,-10 and-15 bar). Results: All 15 isolates had the ability to grow at different drought levels. At the salinity levels of 4 and 10% sodium chloride (NaCl), only 10 and two isolates had the ability to grow, respectively. All of these isolates were capable of dissolving TCP and producing ACC-deaminase, IAA, siderophore and 9 isolates capable of producing HCN. In the presence of salinity of 4% NaCl, all isolates were able to solubilize TCP, while only 8, 13, 6, and 4 isolates were able to produce ACC-deaminase IAA, Siderophore and HCN, respectively. Conclusion: Considering the fact that a considerable amount of Pseudomonas fluorescent isolated from rhizosphere of wheat in this study were able to grow well in salinity of 4%, and also the studied bacteria at different levels of drought stress, in osmotic pressure of-15 Bar or 37. 62% polyethylene glycol (PEG 6000) were able to grow. In addition to salinity and drought resistance, these bacteria were able to produce plant growth promoting components (PGPs) in the presence and absence of salinity. Specially, the results of this study showed that some native isolates of the dry farming soils of the country were able to produce the ACC-deaminase enzyme, although under salinity stress of 4% sodium chloride salt this ability was significantly reduced (46. 6%) and even in some isolates stopped production of this enzyme. Therefore, based on the results of this study, it can be concluded that wheat rhizosphere soil of dry farming can be a suitable source for isolating Pseudomonas fluorescent bacteria, some of these isolates have the ability to maintain their growth promoting properties in saline conditions. In addition, the use of such bacteria (phosphate solubilizing pseudomonads) can reduce some of the limitations of wheat production in the drylands, as the use of fertilizers in dry conditions increases soil salinity. However, their application as bio-fertilizer requires further greenhouse and field tests.

Background and Objectives: Weirs are widely used to measure flow, water deviation and flow control in open channels. So far, most of the weirs used in the diversion dams were linear. In this study, the effect of sediment properties transmitted in the main channel and intake channel has been studied by changing the weir shape from linear to duckbill with magnification 2 and 3. Materials and Methods: The research was carried out at the Hydraulic Laboratory of the Water Engineering Department of Bu-Ali Sina University. The experiments were carried out in flume lengths of 10 meters, width of 83 cm and height of 50 cm. weirs, gate and intake channels with accessories and reservoir of sediment collection were also designed and added to the collection. For testing, non-adherent sediment particles with a grain size of approximately the uniform size and with a diameter of 0. 35 mm were used. Experiments were carried out with a layer of sediments of thickness of 4 cm and slope of 0. 005 and in two discharges of 40 and 60 liters per second. At first, intake gate and sluice way was closed and a flow with a small discharge entranced until the flow passed on the weir. Then, the discharge increased to 60 or 40 liters per second and intake gate was opened to a certain amount and the experiments were carried out for a certain period of time. Afterward, the entered sediments into the intake channel and also the accumulated sediment in the mesh of the end of main channel were collected, dried and weighted, and the concentration of sediments entering the intake channel and downstream of sluice way were calculated. Results: The results showed that in the discharge of 40 and 60 liters per second and weir with a magnification of 1, the concentration of sediments deposited into the intake channel (Csin*6*10-6) was 0. 25 and 0. 65, respectively, which will be equal to 0. 65 and 2. 9, respectively, by increasing the magnification of the overflow to 3. By increasing the intake discharge ratio from 0. 3 to 0. 4, these values for magnification 1 would be 0. 75 and 1. 7, respectively, and for magnification 3 would be 0. 9 and 1. 5, respectively. In discharge of 60 liters per second and the intake discharge ratio of 0. 25, with increasing sluice gate discharge ratio from 0 to 0. 1, the sediment concentration in the intake channel increased from 0. 25 to 1. 2 for weir with magnification of 1 and from 2. 45 To 7. 1 for weir with magnification of 3, respectively. By increasing the intake discharge to 0. 4, these values vary from 2 to 5. 1 for magnification of 1 and from 4. 8 to 11 for magnification of 3, respectively. Along with the increase in the magnification ratio of the weir, the concentration of sediments deposited into the intake channel in equal intake discharge ratio increases. The increase in intake discharge ratio and the increase of sluice gate discharge ratio also increase the concentration of sediments deposited into the intake channel. The same applies to the sluice gate. This means that increasing the magnification, increasing discharge, increasing the intake discharge ratio of and increasing sluice gate discharge ratio will increase the concentration of sediment input into the sluice gate. Conclusion: Increasing the magnification reduces the flow head and also reduces the flow depth in the upstream, and as a result, velocity and shear stress rate of the flow increases, which results in the transfer of more sediment to the downstream and, consequently, to the intake channel. Increasing the opening of the intake gate and, consequently, increasing the intake discharge rate, increases the concentration of sediments deposited to the intake channel, However, increasing the weir magnification has no Significant influence on efficiency (the sediment concentration ratio of the intake channel to the main channel). But increasing the sluice gate discharge ratio leads to a decrease in the efficiency of the concentration of sediments entering the intake. So that the efficiency has been changed by increasing the discharge rate from 0. 25 to 0. 4, from 2. 8 to 2. 3 for weir with magnification 1 and from 3. 3 to 2 for weir with magnification of 3.

Background and Objectives: Simulation of groundwater is very important in order to groundwater table prediction, hydrogeological and management studies, construction of structures, agricultural use, and access to high quality groundwater. In recent decades, artificial intelligence models have been tested for simulation of aquifers due to the complex and nonlinear properties of groundwater systems. The purpose of this study is comparison of the different models of artificial intelligence (artificial neural network, multi-layer perceptron, radial basis function and neuro-fuzzy) and its composition with geostatistics methods for modeling of the groundwater table in the Sarakhs plain. Investigation of recent studies shows that simulation of groundwater level with artificial intelligence methods in different regions has different results. Materials and Methods: Sarakhs County with more than 5000 Km2 area is located in 60° 30' to 61° 15' eastern longitude and 35° 55' to 36° 40' northern latitude. Sarakhs Plain ُs aquifer is unconfined type and shaped from a layer of alluvial. In this research, groundwater level data of 18 wells, rainfall and potential evaporation in statistical period (1992-2016) were used. The affected area of each climatology station was determined by Thiessen ُs method and climate data of each station generalized to wells which situated in related polygon. The artificial intelligence models that used in this study were Multi-Layer Perceptron (MLP), Radial Basis Function (RBF) and Neuro Fuzzy (NF) and geostatistics methods were Kocriging, Kriging and Inverse Distance Weighting. 70 percent of the input data was used for training of models and the remaining 30 percent was used to test them. To assess the results of simulations with Artificial Intelligence models, the criteria of correlation coefficient (R), Mean Absolute Error (MAE) and Coefficient of Determination (R2) and for evaluation of geostatistics method the criteria of Root Mean Square Error (RMSE) and Mean Square Error (MSE) were used. Results: The results showed that the multi-layer perceptron model is more accurate than other models, according to R=0. 77, R2=0. 62 and MAE=0. 80. To determine the best geostatistical model, for spatial prediction of the groundwater level, the results of multi-layer perceptron model were used as input data. The results showed that Kriging method with RMSS=1 and RMS=0. 066, is better model to spatial simulation of groundwater level in Sarakhs plain and based on Kriging method, the maps of groundwater level in each year was designed. Assessment of these maps showed that the most decline of groundwater level is in the north parts of Skaraks plain and south part of this Palin has a little declining of groundwater level. Conclusion: The combination of the MLP model and the Kriging interpolation method is a suitable and low cost solution for simulation of the groundwater level in the Sarakhs Plain. It is suggested that if possible more dependent variables be used to increase the accuracy of artificial intelligence models. Also, for better prediction of groundwater level, the other artificial intelligence models with different algorithms should be used.

Background and Objectives: Zinc-released (Zn) in the rhizosphere soil is the primary factor that affects bioavailability of Zn. To investigate the effect of root activity on Zn release in a polluted soil at different harvesting times, a greenhouse experiment was conducted using rhizobox. Materials and Methods: Soil sample was collected from the 0– 30 cm depth of a calcareous soil from agricultural fields located in the Zanjan province, Iran. In order to study the effect of maize root exudates on the Zn release using a rhizobox. The rhizobox was divided into three sections, including a central zone for plant growth (20 mm), near rhizosphere zones (20 mm), and non-rhizosphere zones (40 mm). Eight seeds were sown per rhizosphere zone and subsequently thinned to two plants. Plants were harvested 30, 60 and 90 days after germination. This research was conducted in a factorial design, with 3 replications, three levels of time (30, 60 and 90 day) and three zones classified based on their distance from root. The kinetics of Zn release in non-rhizosphere and rhizosphere soil was determined by successive extraction with DTPA-TEA in a period of 1 to 528 h at 25± 1 C. Results: The results showed that The results showed that with increasing time, the cumulative released of Zn increased. Also, the amount of cumulative released of Zn in the rhizosphere soils were significantly (P<0. 05) lower than near rhizosphere and non-rhizosphere soils at 60 days after planted, due to plant uptake. There were also significant differences between harvesting times. The mean of Zn released in the bulk, near root and the rhizosphere soils were 278. 5, 269. 18 and 259. 7 mg kg-1, respectively at 60 days after planted. Comparisons of R2 and SE values indicated that the power function and first-order kinetic equations described the reaction rates fairy well, as evidenced by the high coefficients of determination and low standard error of the estimate. In addition, the parameter b in power function was <1 in all samples, indicating that the Zn released rates were decreasing with time. The best model for describing extraction data for bulk and rhizosphere soils was the power function kinetic equation. Conclusion: The results of this research revealed that Zn release characteristics that are helpful to estimate the Zn supplying power of soils in the maize rhizosphere, which is different from the bulk soil. Also, the amount of zinc released has been influenced by the different times of the crop period, which indicates that during the plant growth period, the release rate of the elements varies over time.

Background and Objectives: Soil moisture is one of the key variables which by controlling evapotranspiration processes influences the water cycle and heat exchange between the earth and the atmosphere. The amount of soil moisture is also important for hydrological, biological and biochemical cycles. With the help of soil moisture information in regular intervals, the degree of drought development can be determined in regions with dry climates. Furthermore, continuous monitoring of soil moisture in agricultural areas can help to plan irrigation of crops effectively. Soil moisture is also used to identify areas susceptible to fire in forest areas. Therefore, monitoring of soil moisture is important in any regions and different time periods. Due to factors such as lack of uniformity in physical properties of soil, topography, land cover, evapotranspiration and rainfall, soil moisture is known as a variable factor in spatial and temporal intervals. Therefore, the use of conventional and traditional methods for soil moisture determination (such as gravimetric and neutron probe) is not appropriate to understand the spatial and temporal variation of this parameter in large scales. To resolve this problem in past two decades, remote sensing technology (especially in visible/infrared spectrum) widely used to estimate of soil moisture indirectly. The objective of this study was to estimate surface soil moisture using Normalized Difference Moisture Index (NDMI), Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST). Materials and Methods: For this purpose, Landsat 8 satellite imagery was downloaded at the same time as ground sampling. The samples were transferred to the laboratory and soil moisture was measured by weighted method. Then, using the expert software such as ArcGIS, the indices were estimated and the values of these indicators were transferred to SPSS software for statistical regression. In this study, a PTF were obtained to predict soil moisture condition using LST and NDVI and NDMI derived from Landsat 8 data. Multiple linear regression method was used to derive the PTF. After derivation of the pedotransfer function, the accuracy of the derived PTF was evaluated. This research was carried out in the Dehzad area of Izeh city of Khuzestan province. Results: Comparison between measured and predicted soil moisture values indicated that the PTF had good prediction (R2=0. 78), Coefficient of Residual Mass (CRM), Mean Absolute Error (MAE), Modified Coefficient Efficiency (E), Modified Index of agreement (d) also showed that the model had good performance (CRM=0. 001, MAE=0. 0013, E=0. 9998 and d=0. 9999). Furthermore, a soil moisture map was obtained for the study area. The result indicated that Normalized Difference Moisture Index (NDMI), Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST) can be used to predict soil surface moisture content successfully. Conclusion: The result of this research has been presented by a PTF and in the form of soil moisture map. The soil moisture map simulated by this model can predict 78% of soil moisture variation in the region.

Background and Objectives: The importance of water as a living environment is not covered by anyone. The bottlenecks caused by population growth and pressure on water resources have made it imperative to conserve these resources. Benzene is an aromatic compound with the formula C6H6. This substance is highly toxic and carcinogenic and is one of the pollutants in the refinery wastewater. The inadequate disposal of such wastewater and no reduction of its pollutants have created many environmental problems. For this purpose, the purpose of this study was to synthesize a porous nano-absorbent agent using chitosan as an inexpensive and environmentally friendly adsorbent for removing benzene from aqueous solutions and purifying contaminated waters. Materials and Methods: Chitosan nanoparticles were made from chitosan powder made by Sigma Aldrich and 1% acetic acid solution. To characterize the physical, chemical and structural properties of chitosan nanoparticles, X-ray diffraction (XRD), infrared spectrometer (FTIR) and scanning electron microscopy (SEM), the effect of different pH parameters, initial concentration of benzene solution, absorbent dose and time Contact checked. The concentration of benzene is determined by the UV-Vis Array spectrophotometer apparatus of Photonix Ar 2015 at 254 nm and analyzed using Excel and SPSS software. Results: According to the results, the optimum amount of benzene adsorption was obtained at pH 4. By increasing or decreasing the pH of the solution, the efficiency of benzene removal decreased. Also, with increasing contact time from 5 to 120 minutes, the efficiency of benzene removal decreased from 96. 86 to 89. 28%. By increasing the initial concentration of benzene, the removal efficiency had an upward trend and the highest removal percentage was obtained at a concentration of 70 mg/l, equal to 78. 57%. Also, the results showed that by increasing the absorbent dose, the removal efficiency of benzene decreased and the highest percentage of removal in the absorbent dose was 0. 01 g, 82. 85%. In optimal conditions, the highest percentage of benzene removal was determined to be 85. 66%. Conclusion: The results of this study showed that nanochitosan adsorbent has a high efficiency in adsorption of benzene from aqueous solutions. Since nanochitosan is of natural origin, it can be used as an environmentally friendly and inexpensive absorbent to remove aromatic compounds from aqueous solutions.

Background and Objectives: The evaluation of biological parameters of soil quality plays an important role in assessing the land management and sustainability of agricultural systems. For this purpose, the biological properties of soil quality, which are sensitive to farming are measured and investigated. The aim of the present study is to evaluate the biological changes forest soil quality after converting to the paddy field and determining the most sensitive properties to disturbance of an ecosystem and the creating a minimum set of data from these parameters using the factor analysis method. Materials and Methods: The present study was performed in Poplar research station in Guilan Province. The soil samples collection were done in both natural forest and closest paddy field from five different depth (0-20, 20-40, 40-60, 60-80 and 80-100 cm). The data were analyzed as a factorial test in a completely randomized design with three replications. The factors including the type of land use in two levels and soil depth in five levels were studies in three replications. Therefore, the statistic population of the present study was 10 treatments (5×2=10) with three replications (totally 30 test units). In the study, the microbial respiration, the mineralization percentage of carbon, the microbial biomass carbon, microbial fraction, and the metabolic coefficient of the samples were measured and the sensitivity index to each feature was calculated. The data were analyzed using SAS software. Mean comparison of parameters of Duncan’ s test and factor analysis using principal component analysis method were performed. Results: The results of the study showed that any land use changes from forest to paddy field led to increase the mineralization percentage of carbon and the metabolic coefficient by 28 and 21% respectively. However, microbial biomass C (61%), microbial respiration (31%), and basal respiration (49%) were reduced. Sensitivity index (SI) indicated that microbial biomass is more sensitive than other parameters to land use. The use of principal component analysis (PCA) showed that two factors could explain more than 70% of the variance in microbial biomass and carbon mineralization percentage and more than 60% of the variance in the amount of carbon mineralization, basal respiration, and a metabolic fraction (quotient). These parameters represent the maximum communality estimation, and the microbial fraction showed the minimum relative importance among the estimates of the total communality values. Conclusion: The change in land use from forests to the paddy fields had an adverse effect on the biological parameters of soil quality. This reduces soil health and the potential for carbon sequestration in the soil. Therefore, cultivation in these lands exacerbates soil degradation and stopping the process results in longer recovery and resilience time.