Showing 240 results for Model
M.j. Zareian, R. Seraj Ebrahimi, H. Dehban,
Volume 28, Issue 3 (10-2024)
Abstract
In the present study, the impact of climate change on maximum temperature and daily precipitation in 16 weather stations was investigated in the Sefidrood Basin from 2023 to 2052. 10 AOGCM models related to the sixth IPCC Assessment Report (CMIP6) were ranked based on their ability to simulate temperature and precipitation in the historical period (1980 to 2014). Then, the maximum temperature and daily precipitation outputs of the best model at each weather station were extracted using the LARS-WG downscaling model under three emission scenarios SSP126, SSP245, and SSP585 from 2023 to 2052. The Mann-Kendall test (95% confidence level) was also used to investigate the trend of changes in the average maximum temperature and maximum daily precipitation. The results showed that different AOGCMs have different accuracies in simulating temperature and precipitation in different regions of the basin, and their accuracies in simulating temperature were better than simulating precipitation. In general, the IPSL-CM6A-LR and HadGEM3-GC31-LL models had the best performance in simulating maximum temperature and precipitation, respectively. Results also indicated that the mean maximum temperature will increase between 0.9 and 2.8 °C in different emission scenarios. Also, the mean maximum daily precipitation will change between -8.6 and 7.17 mm in different emission scenarios.
M. Amiri, E. Fazel Najafabadi, M. Shayannejad,
Volume 28, Issue 3 (10-2024)
Abstract
Piano key weirs are a type of non-linear weir that have a higher discharge coefficient than similar linear weirs. These hydraulic structures have a lightweight foundation and a simple structure is designed and installed on dams and drainage channels. Due to the high efficiency of these weirs, the investigation of downstream scour and ways to reduce it has been the focus of engineers in recent years. In the present study, a trapezoidal type C piano key weir, three discharges, and three tailwater depths were used. Two obstacles with heights of 0.02 and 0.04 meters were also used at the end of the weir exit keys. The results showed that the presence of an obstacle reduces scour at the toe of the weir. The amount of reduction in scour at the toe of the weir was greater in the weir with a larger obstacle height than in the weir with a smaller obstacle height, and in both cases was less than in the simple weir. The presence of an obstacle reduces the maximum depth of scour and moves the distance of the maximum depth of scour away from the toe of the weir. In the weir with obstacle heights of 0.02 and 0.04 meters, compared to the weir without an obstacle, the amount of maximum scour depth is approximately 16.4% and 26.9% less, and the distance of the maximum scour depth is approximately 8.7% and 19.1% more than the weir without an obstacle. The scour index in weirs with obstacles is less than in weirs without obstacles, which can reduce the risk of weir overturning. The lowest value of the scour index was observed in the weir with an obstacle height of 0.04 meters, which is approximately 41.2% less than the weir without an obstacle.
M.a. Abdollahi, J. Abedi Koupai, M.m Matinzadeh,
Volume 28, Issue 3 (10-2024)
Abstract
Today, the problems related to floods and inundation have increased, particularly in urban areas due to climate change, global warming, and the change in precipitation from snow to rain. Therefore, there has also been an increasing focus on rainfall-runoff simulation models to manage, reduce, and solve these problems. This research utilized SewerGEMS software to explore different scenarios to evaluate the model's performance based on the number of sub-basins (2 and 8) and return periods (2 and 5 years). Additionally, four methods of calculating concentration time (SCSlag, Kirpich, Bransby Williams, and Carter) were compared to simulate flood hydrographs in Shahrekord city. The results indicated that increasing the return period from 2 to 5 years leads to an increase in peak discharge in all scenarios. Furthermore, based on the calculated continuity error, the Kirpich method is preferred to estimate the concentration-time in scenarios with more sub-basins and smaller areas. For the 2-year return period, a continuity error of 4% was calculated for the scenario with 2 sub-basins, while for the 5-year return period, the continuity error was 19%. On the other hand, the SCSlag method is preferred to estimate the concentration-time in scenarios with fewer sub-basins and larger areas. For the scenario with 8 sub-basins, a continuity error of 16% was calculated for the 2-year return period, and 11% for the 5-year return period.
M. Neisi, M. Sajadi, M. Shafai Bejestan, J. Ahadiyan,
Volume 28, Issue 3 (10-2024)
Abstract
Side weirs are hydraulic structures employed in irrigation and drainage channels as diversion devices or head regulators. The increasing efficiency of the structure of side weirs for constant head has been one of the concerns of researchers in the last decade. The use of different forms of sharp crest, labyrinth, piano key, and increasing the length of the overflow by changing the geometry of the crest have been investigated. In this research, a new type of triangular-shaped side weir has been studied in the laboratory under different hydraulic conditions in sub-critical flow conditions. The results demonstrated that by inclining the crests of the triangular side weir, the amount of vortex created at the entrance of the opening was reduced. So the discharge coefficient and the flow volume over the side weir showed an increase of up to 27% and 48%, respectively, compared to the normal triangular and rectangular side weirs. Also, after analyzing the data, a non-linear equation was presented to estimate the discharge coefficient with the dimensionless parameters of the ratio of the upstream depth to the weir height (y1/p) and the upstream Froud number (Fr1) with an accuracy of ±15% and NRMSE=0.134.
M. Tajsaeid, M. Gheysari, E. Fazel Najafabadi, R. Jafari, E. Seyfipurnaghneh,
Volume 28, Issue 3 (10-2024)
Abstract
Soil moisture is one of the important and determining factors for plant growth, the rate of evaporation and transpiration, and water management in the field. Therefore, its measurement has special importance. The surface soil has a great diversity in soil moisture and different methods were used to measure this property. Due to the problems of contact methods of soil moisture measurement, remote sensing has gained attention because of the possibility of analyzing and monitoring soil moisture on a large and global scale. In this research, satellite data and moisture measured in selected fields located in Hormoaz Abad Plain have been analyzed and compared. Sentinel-2 satellite data have been analyzed using the Google Earth Engine system. The results of this research showed that the use of triple indices in the OPTRAM model to estimate moisture is not very accurate, but the use of the EVI plant index has provided better results than the other two indices.
M. Ranjbari Hajiabadi, J. Abedi Koupai, M.m. Matinzadeh,
Volume 28, Issue 4 (12-2024)
Abstract
Urban runoff is a serious issue due to urbanization and climate change. Therefore, paying attention to rainfall-runoff simulation models is important to manage and reduce adverse consequences. In this research, the performance of the SewerGEMS software was examined by studying different modes based on the number and area of sub-basins. Two modes, consisting of nine and seventeen sub-basins, were evaluated with varying durations of rainfall of 6 and 12 hours. Additionally, the performance of three methods for calculating concentration time (Kerpich, Brnsby-Williams, Carter) was compared to simulate flood hydrographs in Minab City. The results showed that the total volume of produced runoff in the nine sub-basins was 4% higher than in the seventeen sub-basins. The maximum runoff peak flow in the nine sub-basins was also 20% higher than in the seventeen sub-basins. Furthermore, the Brnsby-Williams method exhibited the least software continuity error among the three calculation methods for concentration time. On the other hand, the Carter method had the highest continuity error. The concentration time calculated by this method in some sub-basins exceeded the 6-hour duration of rain. A t-test was performed to compare the peak discharge data obtained from the Kerpich and Barnesby-Williams methods. The results indicated a significant difference between the data from the two methods at a 95% confidence level (p<0.05). Considering that the Kerpich method is suitable for calculating concentration time in small basins, it was used to compare the nine and seventeen sub-basins. Based on the findings, it was observed that merging the sub-basins and reducing their number from seventeen to nine resulted in an increase in the total volume of produced runoff from approximately 123,839 cubic meters to 128,446 cubic meters, as well as an increase in the maximum peak flow of runoff from about 2.400 m3/s to 2.884 m3/s. This demonstrates an increase in both the total volume and maximum peak discharge of the runoff.
F. Safari, H. Ramezani Etedali, A. Kaviani, L. Khosravi,
Volume 28, Issue 4 (12-2024)
Abstract
Climatic factors play an important role in the growth and development of plants and affect agriculture. The tolerance threshold of plants for each of these factors is limited. Any change in these factors can directly and indirectly have significant effects on agricultural production. Meanwhile, temperature stress is one of the most important damaging phenomena that causes many problems for production and yield. In this research, the time of occurrence of temperature stress with a statistical period of 44 years (1980-2023) and the relationship between air temperature with yield and biomass were investigated. According to meteorological data, June, July, and August were known as the hottest months of the year. On the other hand, the most heat waves were observed in July and August in the years 1997, 2014, and 2018, which led to a decrease in the quality of the product or the loss of the plant. According to the model evaluation results, the accuracy of the model in simulating days to flowering and days to maturity was confirmed using R2 (0.8 and 0.51) and NRMSE (15.36 and 7.12). Also, the model was simulated for the studied fields with deviation percentages of 1.92, 5.65, 4.94, 1.58, 0.96, and 1.49%, respectively. It showed that the model had a satisfactory performance and could be used for maize production planning. Next, the relationship between temperature, yield, and biomass was investigated, and there was a negative and significant relationship between temperature, yield, and biomass at the 99% confidence level.
H.r. Owliaie, A.r. Salehi, Gh.r. Zareian,
Volume 28, Issue 4 (12-2024)
Abstract
The spatial distribution of soil characteristics is a fundamental factor for planning sustainable agriculture. Geostatistical methods are widely used to determine the spatial variability of soil characteristics in unknown locations. This research was carried out to evaluate the geostatistical methods for zoning some characteristics of the Darnagan area including agricultural (crop and horticultural) and pasture land uses in the southwest of Shiraz. 134 surface soil samples were collected with a grid pattern from three different land uses, and some of their fertility characteristics were measured. The results based on precision criteria revealed that exponential co-kriging was the best method for interpolating P, J-Bessel for K and Fe, stable model for Ca and Mn, tetra spherical model for N and Mg, Gaussian model for Zn, and rational quadratic model for Cu. The weak spatial structure was obtained for Zn, medium for N, K, and Mn, and strong for other variables. According to spatial distribution maps, 96, 28, and 24% of the studied area are deficient in nutrients N, P, and K, respectively. Concerning micronutrient elements, 78% and 63% of the region are deficient in Fe and Zn, respectively. The statistical comparison of the studied characteristics indicated a significant difference in P, K, Fe, Mn, Ca, Mg, and CEC amounts in different land uses.
R. Daneshfaraz, M. Majedi Asl, T. Omidpour Alavian,
Volume 29, Issue 1 (4-2025)
Abstract
Weirs play a crucial role in flood management and dam safety, accounting for a significant portion of the construction costs of dams. The selection of floods with long return periods for flood design is of utmost importance. However, in some cases, increasing the weir capacity by widening it may be impossible due to topographical limitations. One solution to enhance the flow capacity of weirs is the application of labyrinth weirs. These weirs increase the effective length of the weir crest within a given width, allowing for the passage of higher flow rates while maintaining similar hydraulic conditions. In this study, the hydraulic performance of labyrinth weirs is investigated using the Flow3D numerical model and laboratory data. Since laboratory experiments are time-consuming and costly, employing numerical simulations to achieve more accurate and reliable results for evaluating the hydraulic behavior of labyrinth weirs is prioritized. The results of the simulations indicate that the Flow3D software, utilizing statistical parameters such as R², DC, and RMSE, achieves values of (0.9805, 0.9725, and 0.0142), respectively. This demonstrates its capability to model the flow passing through weirs with high accuracy. The obtained values of the discharge coefficient in Flow3D show a high agreement with the laboratory data from Crookston. The approximate alignment of these results indicates the high accuracy of the numerical model. Additionally, in comparison to different discharges, the relative computational error observed for flow rates of 0.35, 0.6, and 0.44 (cubic meters per second) was approximately 0.5 percent, while for flow rates of 0.3, 0.4, and 0.57, the corresponding errors were 8, 6, and 4 percent, respectively. The results indicate that these tools can be effectively utilized in precise hydraulic analyses and the optimization of weir designs, irrigation systems, and fluid dynamics phenomena.
M. Zarinibahador,
Volume 29, Issue 1 (4-2025)
Abstract
The calcium carbonate equivalent (CCE) in soil is one of the most important soil properties. Predicting the amount of calcium carbonate equivalent in soil is essential for sustainable soil fertility management. The present study aimed to digitally map calcium carbonate equivalent using auxiliary environmental variables, Landsat 8 satellite images, and predictive models and to present the best models in the Badr watershed in the south of Qorveh district. In the first phase, a geomorphologic map was created using a geologic map and based on the ZINC method in a geographic information system environment. In the second phase, the location of 125 survey profiles was determined using the Latin hypercube technique, and the calcium carbonate equivalent of the soil horizons was measured by acid titration. The auxiliary variables included derivatives of the digital elevation model, remote sensing indices from the Landsat 8 satellite, and a geopedological map. The principal component analysis (PCA) method was used to select suitable auxiliary variables. In the third phase, the modeling was carried out, digital maps of the soil classes and properties were created, and the models were evaluated. Two different cases were investigated in this study to estimate the calcium carbonate equivalent of the soil. In the first case, artificial neural network models, decision tree analysis, random forest, and the K-nearest neighbor model were used for prediction. The multiple linear regression model was also used to combine the results of the models. Among the models used to predict the equivalent amount of calcium carbonate using the 10-fold cross-validation method, the multiple linear regression (MLR) model had the highest prediction accuracy with a coefficient of determination of 0.796 and a mean square error of 6.514. In the 5-fold cross-validation method, the K-nearest neighbor (KNN) model had the highest predictive accuracy with a coefficient of determination of 0.9845 and a root mean square error of 2.1258. Due to the spatial nature of the 10-fold cross-validation method, the use of this method is preferable to the 5-fold cross-validation method. In addition, the most important auxiliary variables in order of importance to predict the calcium carbonate equivalent in soil were the carbonate index, slope direction, geomorphology, the base level of the catchment network, and the slope of the catchment.
F. Zolfaghari, S. Eslamian, A.r. Gohari, M.m. Matinzadeh, S. Azadi,
Volume 29, Issue 2 (7-2025)
Abstract
Drought represents one of the most critical natural disasters, exerting profound impacts on agriculture, society, the economy, and water resources. Various indices are used to monitor drought and its effects. This study aims to monitor drought in the Zayandeh-Rud Basin using the Standardized Precipitation Index (SPI), the Standardized Precipitation-Evapotranspiration Index (SPEI), the Evaporative Demand Drought Index (EDDI), the Palmer Drought Severity Index (PDSI), and the Reconnaissance Drought Index (RDI). All these indices are based on potential evapotranspiration, incorporating parameters such as precipitation, temperature, relative humidity, wind speed, and sunshine duration. These five indices were calculated and evaluated during the statistical period of 1993–2023 for meteorological stations in Isfahan, East Isfahan, Kabootarabad, Daran, Shahreza, Najafabad, and Mobarakeh. After calculating the indices and using spatial zoning maps, the studied stations were compared in terms of these indices. The continuity of dry and wet periods, as well as the intensity of droughts and wet spells, was analyzed. Subsequently, drought intensities during different years in these stations were ranked using the TOPSIS model based on factors such as precipitation, potential evapotranspiration, and station elevation. The results showed that in stations with a dry climate (such as Isfahan, East Isfahan, and Shahreza), drought occurrences (as indicated by higher rankings) have been consecutive over multiple years. Comparing the performance of the indices in the studied stations using spatial zoning maps revealed that the intensity of droughts and wet spells in regions with dry and semi-dry climates was not very significant. However, in areas with humid climates, the fluctuations in drought and wet spell intensities were quite substantial. The findings indicate that the PDSI and EDDI indices are more suitable for evaluating drought in dry climates.
Ali Akbarian Khalilabad, Hojat Karami, Seyed Farhad Mousavi,
Volume 29, Issue 3 (10-2025)
Abstract
The reduction of soil permeability due to the sedimentation of suspended particles is a significant challenge to the efficient operation of artificial recharge systems. In this study, the effects of sediment concentration (0.5, 2, and 4 g/L), soil particle size, and vertical distribution on clogging processes were investigated using laboratory soil column experiments. The results showed a two-phase decrease in permeability: a rapid initial drop caused by the blockage of coarse pores during the first 10 minutes, followed by a second phase where the system reached a relative equilibrium. Higher sediment concentrations led to a faster decline and lower equilibrium values of permeability. Fine-grained soils, despite having lower initial permeability, demonstrated greater resistance to clogging, while coarse-grained soils experienced more severe reductions. Vertical analysis indicated that the most significant permeability loss occurred at a depth of 40-50 cm, while deeper layers showed increased permeability due to the limited penetration of suspended particles. These findings can inform the selection of appropriate materials, the design of subsurface layers in recharge basins, the prediction of system lifespan, and the regulation of sediment load in inflows to enhance the efficiency and sustainability of artificial recharge systems.
Masoumeh Golestani, Sayed Farhad Mousavi, Hojat Karami,
Volume 29, Issue 3 (10-2025)
Abstract
Groundwater is a vital resource for meeting drinking, agricultural, and industrial needs in arid and semi-arid regions of Iran. In this study, quantitative and qualitative changes in groundwater in the Garmsar Plain were modeled using GIS, MODFLOW, and MT3DMS software during the period 2011-2013. Spatial and climatic data were comprehensively processed and prepared in the GIS environment, and groundwater flow was simulated using the MODFLOW model, and water quality changes were analyzed using the MT3DMS model. After validation with field data from 2012 to 2013, the model showed acceptable accuracy with statistical indicators of mean absolute error (MAE) in the range of 0.4 to 0.5 meters and root mean square error (RMSE) between 0.5 and 0.6 meters. The modeling results showed that a 15% increase in water withdrawal led to a decrease in the water table of up to 8 meters, a constant withdrawal led to a decrease of 7 meters, and a 15% decrease in withdrawal led to a decrease of 5 meters in the water table. From a quality perspective, the decrease in withdrawal improved the quality of irrigation water but increased the concentration of some pollutants, which requires the development of effective management strategies to protect groundwater resources. The findings of this study illustrate the importance of sustainable exploitation and smart management of groundwater resources in the Garmsar Plain.
Mohammad Shayannejad, Elham Fazel Najafabadi, Fahimeh Hatamian Jazi,
Volume 29, Issue 3 (10-2025)
Abstract
Regarding the increasing need for water resources and the decline of surface water resources, awareness of these resources is a crucial need in planning, developing, and protecting them. This research was conducted to model the water quality index (the most widely used feature of determining water quality) using machine learning models (Random Forest and Support Vector Machine) in the Zayandehrood River. Regarding the large number of water quality indices, the NSFWQI index was used in this study. First, this index was calculated, and then, input data, including water quality characteristics of 8 stations over 31 years, and the river water quality index were used. In this research, 80% of the data was used in the training stage, and the remaining 20% was used in the evaluation stage. The optimal model was selected based on the evaluation criteria, including R2, CRM, and NRMSE. The results showed that the Support Vector Machine algorithm (0.931 < R² < 0.982, 1.321
Amir Mahjoob, . Fouad Kilanehei, Kheirollah Khademi,
Volume 29, Issue 4 (12-2025)
Abstract
One of the most significant hydraulic issues in determining the opening of river bridges is the lack of flow choking due to a reduction in the width of the flood passage. In this paper, determining the required opening for flow passage at a bridge location has been investigated using the concept of specific energy, one-dimensional, and three-dimensional flow modeling. First, the maximum encroachment of the embankments on the sides of the bridge in the river has been determined in such a way that it does not change the flow situation upstream of the bridge, using the concept of specific energy. The dimensions obtained for the bridge opening have been simulated numerically in two one-dimensional and three-dimensional models, and the flow condition at the bridge site and upstream has been evaluated and compared. The results showed that the one-dimensional numerical model predicts, on average, 67 percent higher amount of afflux than the three-dimensional model, while the maximum shear stress obtained from the one-dimensional model is, on average, 33 percent lower than that of the three-dimensional model. The effect of the bridge skewness on the amount of afflux and other hydraulic parameters of the flow, including bed shear stress and maximum velocity, has also been investigated using a three-dimensional model. The afflux was obtained at a 19.2 percent of normal depth at a skew of 40 degrees.
Nasrin Zamani, Jahangir Abedi Koupai, Saeid Eslamian, Afshin Soltani,
Volume 30, Issue 1 (3-2026)
Abstract
Water scarcity has made the agricultural water footprint a critical measure for sustainable resource management, particularly in water-stressed regions such as Iran. This index depends on various factors, including climate, crop yield, dietary habits, and irrigation/agricultural efficiency, which can be estimated more rapidly using modeling approaches. The SSM-iCROP2 model is a simulation model that has been parameterized and evaluated for over 30 crop species in Iran and has been widely used in studies related to crop yield. Since sugar is a key energy source in the food basket, sugarcane occupies vast cultivated areas in the country. Sugarcane is primarily grown in Khuzestan province. This study aimed to apply the aforementioned model to estimate the blue and green water footprint of this strategic crop, using upscaling methods for both potential and farmer-managed conditions from 1992 to 2022. The results showed that the total water footprint of sugarcane (sum of blue, green, and gray water footprints) was 2,251 and 3,134 cubic meters per ton for potential and actual (farmer) conditions, respectively.
Amir Mahdi Bayat, Mohammad Shayannejad, Mahmood Akbari,
Volume 30, Issue 1 (3-2026)
Abstract
Mathematical models are a suitable tool for surface irrigation design. The EDOSIM model, as a surface irrigation simulation-optimization model, utilizes simulation with the volume balance model and meta-heuristic optimization. In this study, with the aim of improving the simulation of the advanced phase in the EDOSIM model, the Full Hydrodynamic model was replaced by the Volume Balance model for furrow irrigation design, leading to the development of the EDOSIM-HD model. The Saint-Venant equations were discretized using the implicit Preissmann’s finite difference scheme and transformed into a set of nonlinear equations in the form of a system of equations. The resulting system of equations was linearized using the Newton-Raphson method and solved using the Sparse matrix method. The results were compared with the SIRMOD software to validate the simulation. Using the particleswarm solver of the MATLAB software optimization toolbox, the inflow rate as a decision variable was used to optimize the hydraulic objective function consisting of efficiency, adequacy, and uniformity. The results in the experimental field showed that in the initial simulation with an inflow rate of 1.4 lps, important irrigation times, infiltration volume, performance indicators, profiles, and hydrographs showed a deep percolation loss of about 50 percent of water. Also, the results of the EDOSIM-HD model were closer to the Hydrodynamic model of the SIRMOD software than the EDOSIM model. By optimizing and increasing the optimal flow rate (1.8 lps) compared to the initial inflow rate, the advance, cut-off, depletion, and recession times were reduced, and the required infiltration time remained unchanged. The reduction in infiltration volume was also achieved by applying higher inflow rates in less time. All performance indicators also moved closer to their optimal state. Except for Tail Water Ration (TWR), which showed a slight increase of 11 percent (due to higher inflow rate), was negligible compared to the sharp 22% reduction in Depth Percolation Ratio (DPR), and 10% increase in Application Efficiency (Ea). Totally, according to the performance indicators obtained in the validation with the SIRMOD, the simulation of the EDOSIM-HD model was better than in the EDOSIM model in the advanced phase of furrow irrigation design
Seyed Mohammad Mirhashemi, Mohammad Shayannejad, Mahmood Akbari,
Volume 30, Issue 2 (7-2026)
Abstract
Proper estimation of soil water infiltration parameters and Manning roughness coefficient is one of the influential factors in the correct design and evaluation of surface irrigation systems. The EDOSIM model, as a surface irrigation simulation-optimization model, uses a combination of simulation with the Volume Balance model and meta-heuristic optimization. In the evaluation part of this model, the Elliott-Walker two-point method is used to estimate the parameters of the Kostiakov-Lewis infiltration equation. In this study, the Manning coefficient and parameters of the Kostiakov-Lewis infiltration equation were calibrated in furrow and border irrigation using observational advance data. This was done through three methods: Volume Balance model with constant shape coefficients (VB-CC), a combination of Volume Balance and Zero Inertia models (VB-ZI), and Volume Balance model with variable shape coefficients (VB-VC), using a total of 10 data series of border and furrow irrigation evaluation. Then, the ability to calibrate the infiltration parameters and roughness coefficient using a superior method was added to the EDOSIM model. The results showed that the VB-CC model had the best calibration accuracy and precision in 10 farms, according to the average statistical indices R2=0.998, NRMSE=2.4%, and MBE=-0.06. The VB-ZI and VB-VC methods underestimated the advance length even with calibrated values. The use of the VB-CC model instead of the Elliott-Walker two-point method in the EDOSIM model increased the accuracy of simulation and optimization by reducing (improving) the objective function from an average of 0.34 to 0.13 in border irrigation and from an average of 0.86 to 0.36 in furrow irrigation. Therefore, it is recommended to use the VB-CC calibration method in the EDOSIM model as a powerful tool for optimal operation of surface irrigation systems.
Mehdi Naderi Khorasgani, Zahra Ghanavati Behbahani, Rohollah Fattahi, Hossein Samadi Brojeni,
Volume 30, Issue 2 (7-2026)
Abstract
Water erosion is a great issue in Iran, and due to a lack of reliable and sufficient data for the recognition of vulnerable areas, using models is inevitable. This study was designed for the evaluation of the MPSIAC model in the subbasin of Goharbaran in Chaharmahal va Bakhtiari province. The sediments of the reservoir were surveyed and measured after exhausting the water. Landsat-8 data were applied to study land use changes on soil erosion. During intensive fieldwork, 37 surficial (0-20 cm) soil samples were collected and, after pretreatment, were used for some soil physical and chemical analyses. For the determination of 9 MPSIAC factors, we used library, field, and laboratory data. Multitemporal analysis showed that the quality of rangelands has increased, and the surface area of orchards was doubled within 20 years (1994-2014). Sensitivity analysis indicated that the MPSIAC model was highly sensitive to the river erosion factor, while the least sensitive factor was soil. The sensitivity of the model to the runoff specific peak and soil silt percentage was also very high. Application of the MPSIAC model showed that 48% of soils were in moderate and 36% of soils were in severe sediment yield rate classes. Results of sediment measurements indicated that the specific sediment yield was 11.76 t.ha-1.y-1 during 26 years (1988-2014), while the forecasted value by the MPSIAC model was 5.97 t.ha-1.y-1 Despite others' findings, a lower estimation of the model revealed the need for MPSIAC model calibration before using it in similar environments.
Fatemeh Jafarian, Khoshnaz Payandeh, Ahad Nazarpour, Ali Gholami, Kamran Mohsenifar,
Volume 30, Issue 2 (7-2026)
Abstract
The steel industry plays an important role in the release of toxic pollutants, including heavy metals, into the environment. The present descriptive-applied study was conducted in 2022 to identify the sources of heavy metal emissions in surface soils in the vicinity of a steel industry using positive matrix factor and chemical mass balance models. Soil samples (50 samples) were systematically collected from four areas within the steel plant, and a control area of 15 km was established. Five main sources, including the earth's crust (factor 1), vehicles (factor 2), steel industry (factor 3), biomass (factor 4), and other sources (factor 5), were identified as the main factors of heavy metals in the positive matrix factor model. Cobalt, nickel, and zinc had the highest mean concentrations with values of 14.5, 1.21, and 0.92mg kg-1, respectively. Cadmium and Lead showed the lowest concentrations with values of 0.02 and 0.10 mg kg-1 in samples inside and outside the Khuzestan Steel Company area, respectively. Comparing the contribution of different sources in the release of heavy metals in the identified factors showed that the steel industry, other sources, earth's crust, vehicles, and biomass accounted for 24, 23, 19, 18, and 16 percent in the positive matrix factor model and 23, 22, 20, 18, and 17 percent in the chemical mass balance model, respectively. The positive matrix factor and chemical mass balance models showed that there was a high level of soil contamination with heavy metals in the vicinity of the Khuzestan Steel Company in Ahvaz city.
