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.
Kimia Akhavan, M. Heidarpour, N. Pourabdollah,
Volume 28, Issue 3 (10-2024)
Abstract
One of the ways to improve the characteristics of the hydraulic jump in the stilling basin is to use natural and artificial roughness. Recently, due to the advantages of immersed plates compared to other non-continuous artificial roughness, such as the smaller number of these and the vanes' ability to design their geometry and arrangement, it has been approached more. In this article, the effect of submerged vanes with three contact angles of 45°, 75°, and 90° has been investigated on the improvement of the characteristics of a hydraulic jump and its effect on parameters such as the depth ratio, relative length, energy loss rate, and bed shear force coefficient has been evaluated. The results of this research showed that the average effect of submerged vanes on reducing the depth ratio, jump length, and roller length compared to the classical mode is 9.4%, 24.6%, and 28.4%, respectively and the average relative energy loss is 5.5% compared to the classical state and maximum relative energy loss at the angle of 90 degrees of submerged vanes is 6.5%. Considering these results and other conditions such as ease of construction and use, stabilization, and reduction of economic costs among the available choices of sunken vanes, the angle of incidence of 75° is a suitable option for the optimal design of the stilling basin.
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. Barahimi, A.r. Sehhat, H. Kavand, S. Parvizi,
Volume 28, Issue 3 (10-2024)
Abstract
Today, many countries, including Iran, face natural hazards such as ground subsidence, drought, floods, and acute water shortage. Lack of correct management of underground water resources leads to many of these natural hazards. Artificial recharge of aquifers is one of the solutions proposed in the world to deal with these natural hazards, especially ground subsidence. The quantitative and qualitative effects of the effluent treatment plant on the Damaneh Daran Aquifer recharge were investigated in this research. The results showed that aquifer recharge through the distribution of effluents in the Damaneh Daran River has a positive effect on increasing the water level and releasing effluents in the river will enhance the water level in a larger radius regardless of the quality of the effluents. Based on the result of the present study, it is suggested that all the effluent treatment plants be allocated to aquifer balancing in the future. In the part of replacing wastewater with active wells, due to the lack of wells with industrial and green area use in this region, provided advanced wastewater treatment, all wastewater should be replaced with active wells in the agricultural area.
S.m. Abtahi, M. Khosroshahi,
Volume 28, Issue 4 (12-2024)
Abstract
Today, wind erosion and dust are an environmental crisis, not just in desert areas but also in the entire country, and putting many costs. The combat against wind erosion in many desert areas by using oil mulches and the cultivation of compatible plants started in the 40s. However, the use of petroleum in addition to mulching the environmental problems, due to the high costs of purchase, displacement, and dispersion, is not economical. Therefore, the performance of non-oil and chemical mulch on dunes was investigated in Kashan. The research on fertilizer application of mulch under a completely randomized design includes: control (no mulch), a polymer mulch, potas, Fars, Paya, and Akrilik at 3 reps (3 sand hills) and the amount of erosion (with the help of the embedded indices in the hills), the survival of plants cultivated in the form of cuttings and seedlings, the percentage of humidity and temperature of each iteration were measured and variance analyses were performed. Field surveys and the results of the statistical analysis showed that the strength resistance of Fars, Paya, and Akrilik is almost the same. Observation of wood indices showed that Fars, Paya, and Akrilik mulches have almost the same strength in terms of wind resistance (almost no wind resistance). Fars mulch after 8 months of spraying showed small fractures due to the loss of flexibility. The study of soil temperature statistics showed that the treatments under mulch had no significant temperature difference compared to the control treatment. A comparison of soil moisture data indicated a high moisture percentage in the potash mulch treatment. The survival rate of cultivated plants was higher in Paya and Akrilik treatments. According to the results, Akrilik, Paya, and Fars mulch are recommended for sand fixation. One of the limitations of research in desert areas is the uncontrollability of environmental and human conditions. So, it is recommended to close the entire mulching area and use a mobile wind tunnel device at the project site to determine the wind slavery at different speeds.
A.r. Vaezi, F. Besharat, F. Azarifam,
Volume 28, Issue 4 (12-2024)
Abstract
The temporal distribution pattern of rainfall can play a role in the production of runoff and soil loss during rainfall. This study investigated four rainfall patterns: uniform, advanced, intermediate, and delayed rainfall under field conditions. The rainfall height in all rainfall patterns was 20 mm. In the uniform rainfall pattern, a constant rainfall intensity (40 mm h-1) was used and in the non-uniform rainfall patterns, a maximum rainfall intensity of 40 mm h-1 was applied for a 15-minute duration. The experiments were carried out in 60 cm × 80 cm plots on a hillslope with a slope gradient of 9% at three replications. Rainfall patterns were set up on the plots in five events with an interval of one week. The results showed a significant difference between rainfall patterns in runoff and soil loss (p<0.01). This difference was due to the destruction of surface soil structure and the reduction of water infiltration rate, especially during peak time of rainfall intensity (40 mm h-1). The highest runoff occurred in the delayed rainfall (3.43 mm) while, the highest soil loss (61.47 g m-2) was observed in the intermediate rainfall, which was associated with the peak intensity of rainfall at the end of the rainfall and its role in the destruction of the soil structure on the one hand, and the loss of infiltration rate on the other hand. Variation of runoff and soil loss from one event to another indicated that soil loss is in line with runoff production in uniform rainfall, while soil loss did not follow runoff in other rainfalls. Soil loss in these rainfalls was affected by both runoff production and availability of erodible soil particles. These results revealed the necessity of studying the rainfall intensity distribution pattern for accurate prediction of soil erosion and determining soil loss variation event by event in the semi-arid region.
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. Afsharipour, M.r. Sharifi, A. Motamedi,
Volume 28, Issue 4 (12-2024)
Abstract
Drought monitoring in snowy basins requires modifications in common drought indices, called snow drought indices. The latest developed snow index is SZIsnow. The SZIsnow index calculating with special algorithm requires access to the values of 22 different climatic and physical variables, including soil moisture at a depth of 0 to 10 centimeters, soil moisture at a depth of 100 to 200 centimeters, air temperature, water equivalent to snow, runoff from snow melting, snowfall, rainfall, total precipitation rate, evaporation and transpiration, wind speed, surface runoff, groundwater runoff, potential evaporation, air pressure, relative humidity, net latent heat flux, ground heat flux, net sensible heat flux, evaporation from bare soil, evaporation from the canopy, and potential evapotranspiration. So far, the mentioned index has been calculated only on a continental scale. Drought monitoring at the basin scale is important as one of the management aspects of water resources. On the other hand, due to the lack of sufficient information to estimate the mentioned parameters, the use of information from global databases will be a solution. Therefore, in this research, while introducing the process of calculating the SZIsnow index, in the Dez catchment area, extracting the required parameters of the index in a time scale of 3, 6, and 12 months and a period of 41 years (1982 to 2023) using data GLDAS and then drought monitoring of the basin was studied. The results showed that the new SZIsnow index is a multi-variable index that provides the possibility of calculating the index due to the existence of parameters that lack ground observations and on the other hand, the availability of the reliable GLDAS database. Also, the results showed that in the time steps of 3, 6, and 12 months, July at -0.59, June at -0.45, and October at -0.35 had the highest amount of drought, respectively.
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.
M. Kouhdaragh, M. Majedi Asl, T. Omidpour Alavian, N. Nobahari, M. Ayami Lord,
Volume 28, Issue 4 (12-2024)
Abstract
Dams, as man-made artificial structures, play a significant role in providing water in various sectors, including agriculture, industry, electricity generation, and flood control. Various soil compounds such as sand, clay, and stone are used for the construction and establishment of earth dams. In this research entitled "Investigation and analysis of Seepage flow and hydraulic gradient in the body and foundation of Alaviyan earth dam using SEEP/W software", the effects of Seepage flow and hydraulic gradient in the body and foundation are investigated. This research analyzes the details of this process using SEEP/W software and analyzes the obtained results. Theoretical foundations related to Seepage flow and hydraulic gradient in earth dams and their importance in the stability of dams are discussed as one of the most important issues of civil engineering. Methods of controlling water seepage from earth dams include the use of seals, walls made with grout mortar, impermeable cores, metal shielding, and impermeable blankets upstream of the dam. In this study, drains, seals, and clay blankets are used as water seepage control methods. The results show that the use of a watertight wall reduces the amount of Seepage because this wall prevents water from flowing through the body of the dam. In general, this research ends by providing quantitative results and recommendations to improve the stability of dams and reduce the possibility of risks caused by seepage flow and hydraulic gradient, and the important elements that should be considered in the design and construction of earth dams. Reviews. In this study, the effects and performance of earth dams have been investigated using finite element methods, and the performance of dams has been evaluated. GEOSTUDIO finite element software was used for modeling. The results of modeling include the investigation of parameters such as phreatic lines, the effect of the water level behind the dam, the clay blanket, and the water seal. Also, the leakage rate from the dam has been extracted and analyzed for different states defined in the model.
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.
S. Zandi, S. Borumandnasab, M. Golabi,
Volume 28, Issue 4 (12-2024)
Abstract
Quinoa, a nutritionally rich crop with remarkable adaptability to unfavorable environments, exhibits a high tolerance to salinity. Reusing agricultural drainage water is a natural and important method in drainage management that increases farmers' income, sustainable production, and food security. The objective of this study was to investigate the effects of irrigation with agricultural drainage water, salinity stress, and water deficit on the yield and yield components of quinoa (Titicaca) under salinity levels of 2, 10, 15, and 20 dS/m and irrigation levels of full irrigation, 80%, and 60% of the crop water requirements. The experiment was conducted with three replications using a split-plot design with a randomized complete block design (RCBD) at the experimental farm of the Faculty of Water and Environmental Engineering at Shahid Chamran University of Ahvaz, during the fall and spring seasons of the years 2022 and 2023. The water requirement of Qinoa was determined gravimetrically by measuring soil moisture before each irrigation and increasing it to field capacity. The experimental treatments were imposed after seed germination and from the start of cultivation. The plants were harvested and transported to the laboratory for drying and yield component analysis upon physiological maturity. The results revealed that salinity stress had a more pronounced impact on reducing quinoa yield and yield components compared to water stress. The highest and lowest grain yields were observed in the autumn season, reaching 5.45 and 1.8 t/ha under the treatments of S1I1 and S4I3, respectively. Similarly, in the spring season, the highest and lowest grain yields were 3.87 and 0.73 t/ha under the same treatments, respectively.
A. Keshavarz, R. Modarres, S.a.r. Gohari,
Volume 28, Issue 4 (12-2024)
Abstract
This study was conducted to present rangeland bioclimatic zoning for Iran based on the changes in the power spectrum of the average monthly Net Primary Production (NPP) of the rangelands of Iran. Fluctuations of the mean monthly power spectrum of the NPP signal of rangelands of Iran from 2000 to 2022 were analyzed using the Power Spectrum Density (PSD) method in the frequency band between 0-100 Hz. In 24 bioclimatic subzones, there are four common periods in all sites at frequencies of 0 (no change is repeated), 8.34 (3.59 days), 16.66 (1.80 days), and 25 (1.2 days) Hz observed, which shows that the major data changes occur in those periods and that the NPP changes of Iranian rangeland are more influenced by global and regional effects than local effects. The maximum power of these spectra is concentrated in high time scales. Therefore, cycles with lower frequency (higher time scale) are more important than cycles with higher frequency (shorter time scale) and show that the changes of NPP in Iranian rangelands have long-duration cycles under climate fluctuations. In the present research, Iran was classified into 5+1 rangeland bioclimatic zones using the results of the monthly mean power spectrum of the NPP signal of rangelands, the Wards clustering method, and the Euclidean square distance. It seems that this method provides a proper match between biological boundaries and climate. Pearson correlation coefficient was used to investigate the coherence of rangeland bioclimatic regions within each homogeneous group. Correlation results showed a significant spectral density similarity within groups at the significance level of 0.01% between rangeland bioclimatic regions, especially in the second and fifth clusters.
M. Niroubakhsh, A.r. Masjedi, M. Heidarnejad, A. Bordbar,
Volume 28, Issue 4 (12-2024)
Abstract
The application of flip bucket and triangular launchers with different shapes has been given more attention due to safety and better energy consumption to protect the downstream bed of water structures, as well as economic benefits compared to other energy consumers. The objective of this research was to investigate the energy loss of the passing flow in the dentated flip bucket and dentated triangular sill spillways in laboratory and numerical conditions. Physical and numerical modeling was used in a rectangular flume with a length of 9 meters, a width of 0.5 meters, and a height of 0.5 meters, flip bucket, and triangular spillways with dentated with specific dimensions according to the USBR standard in different discharges intensities in laboratory and numerical conditions. The amount of energy loss in the dentated flip bucket spillway was 71.4% and the dentated triangular sill spillway was 74.8% in laboratory conditions, which showed that the dentated triangular sill spillway has a better performance in terms of energy loss than the flip bucket and triangular spillway. The results showed that the shape of the spillway geometry and the presence of the dentated at the end of the structure is an important and influential factor in the amount of energy loss of the currents passing through the dentated flip bucket and dentated triangular sill spillways, which causes more broken and compressed flow lines and, as a result, an increase in speed at the moment. The launch and finally the relative loss of energy is more downstream of the structure. After determining the better performance of the dentated triangular sill spillway in energy loss, the numerical simulation of the dentated triangular sill spillway was performed using the numerical calculation method in Flow-3D software. The results of the analyses indicated that the amount of energy loss in the dentated triangular sill spillway in the numerical calculations was 87.5%, which showed the alignment and correctness of the tests performed with the laboratory conditions.
E. Jafari Nodoushan, A. Shirzadi,
Volume 28, Issue 4 (12-2024)
Abstract
The rapid and complex movement of sediments in rivers and coastal areas with highly erosive and unsteady flows presents river engineers with numerous problems in the geomorphology of alluvial rivers. Accurately predicting these complex processes in the water-sediment system (a multiphase, dense, granular flow system) is still a major challenge for mesh-based models. Due to the ability of meshless Lagrangian methods to model large deformations and discontinuities, meshless Lagrangian methods can provide a unique way to deal with this complexity. In the current research, the capabilities of the weakly compressibility moving particle semi-implicit (WC-MPS) model in soil-fluid interaction modeling are developed to enable the modeling of sediment transport and erosion effects behind coastal walls. In this method, granular material is considered a non-Newtonian and viscoplastic fluid. The 𝜇(I) rheological model has been used to predict the non-Newtonian behavior of the granular phase. To verify the application of the present model in simulating the interaction of liquid and solid phases, first, the widely used problem of dam break on an erodible bed was modeled. The NRMSE model was calculated to be approximately 6%, which indicates the efficiency and accuracy of the target model in this problem. At the end, the scouring of coastal walls was simulated by the WC-MPS method using 𝜇(I) rheology model. Investigations show that the processes related to erosion and scouring can be well modeled using the current Lagrangian method. The numerical results show excellent agreement with the laboratory measurements. It should be noted that the mean error of the mentioned model is estimated to be 10%.
Y. Sabzevari, S. Eslamian,
Volume 28, Issue 4 (12-2024)
Abstract
This study aims to investigate the possibility of hydrological simulation of the Azna-Aligoudarz area, which is located in the upper reaches of Karoun Bozorg basin and in the east of Lorestan province. To carry out this research, the daily meteorological data related to the Aligoudarz synoptic station and the rainfall of Kamandan and Dareh Takht rain gauge stations in the period of 1991-2023, the observational discharge related to the Marbareh hydrometric station in the period of 1991-2021, soil map, land use and digital elevation map of Azna-Aligoudarz basin was used. The period of 1991 and 1992 was considered for warm up the model, the validation period from 1993 to 2016, and the validation period from 2017 to 2021. Based on the simulation done in this area, the model had weakness in simulation. After the initial simulation, the model was calibrated. After analyzing the sensitivity of different parameters, 22 effective parameters were selected and the model was calibrated. The evaluation results showed that the NSE value of 0.60 and 0.56 and the R2 coefficient value of 0.61 and 0.78 respectively were obtained for the calibration and validation stages. Based on the coefficients obtained in both calibration and validation stages, it was found that the model had a satisfactory accuracy in the hydrological simulation of Azna-Aligoudarz area.
T. Mohammadi Arian, G. Rahimi, R. Khavari Farid,
Volume 29, Issue 1 (4-2025)
Abstract
Heavy metal pollution is considered a serious risk to the environment and human health due to its toxicity and indestructibility. Measuring and monitoring little concentration (even lower than the detection limit of the device) in the case of dangerous and biostable pollutants such as cadmium in natural water samples is a necessity. Solid-phase extraction using carbon adsorbents is the most efficient and common method of pre-concentration of heavy metals from environmental samples. The carbon adsorbent used in solid phase extraction must have favorable physical and chemical characteristics, along with low cost and biocompatibility. In this research, Aphanocapsa cyanobacterial cells were used as a cheap precursor to make a microscale absorbent using the hydrothermal method. The qualitative and absorption characteristics of this adsorbent were evaluated using instrumental analysis tests and chemical tests based on cadmium. The absorbent is made in the form of relatively spherical particles (with a size of less than 10 micrometers) with a rough surface and a specific surface area of 382.02 square meters per gram. The efficiency of cadmium absorption of absorbent was in a wide range of pH (3 to 8) and more than 90% due to the buffering effect. The absorbent surface was rich in oxygen and nitrogen functional groups, such as hydroxyl, isothiocyanate, and carbonyl. The cadmium absorption isotherm was the best fit with the Freundlich nonlinear model, and the cadmium absorption rate was the best fit with the pseudo-second-order nonlinear model. The calculation variables related to the Freundlich model, including the inverse of the absorption intensity, showed that the adsorbent has a great tendency to absorb low concentrations of cadmium. Cadmium had the most and least competition for absorption on the adsorbent with alkali metal cations and heavy metal cations, respectively. The resistance of the adsorbent against the increase of ionic strength and the concentration of competing cations was equal to 4 and 20 mg/liter, respectively. The washing efficiency of the adsorbent loaded in the adsorbent-to-solution ratio (1:1000), at a normal concentration of 0.3 and a volume of 160 microliters of detergent (nitric acid), reached its maximum value. According to the findings of this research, the carbon adsorbent originating from the cyanobacterium Aphanocapsa can be an efficient adsorbent to use in the solid phase extraction of cadmium to reduce environmental pollution due to its unique properties.
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. Naderi Khorasgani, R. Amiri, A. Karimi, J. Mohammadi,
Volume 29, Issue 1 (4-2025)
Abstract
The soils of the Shahrekord plain, part of the Beheshtabad watershed subbasin in Shahrekord County, Chaharmahal va Bakhtiari province, have been used for crop production and domestic animal feeding for centuries, yet the soil quality of this plain has been overlooked. Therefore, assessing the quality of Shahrekord plain soil is essential. This research aimed to evaluate the physical soil quality of the plain using soil quality indices such as the Integrated Quality Index (IQI) and Nemoro Quality Index (NQI). A randomized compound sampling strategy was employed, and 106 surficial (0-25 cm) soil samples were collected during intensive fieldwork. Following pretreatments of the soil samples, several key soil characteristics were measured using standard methods, which were compiled into a Total Data Set (TDS) and used to calculate IQITDS and NQITDS. The minimum effective data set (MDS) was selected, and weights for the quality indices were determined using TDS and Principal Component Analysis (PCA). The minimum data set included the soil sand percentage, soil organic matter percentage, mean weighted diameter of aggregates, soil moisture at field capacity, bulk density, soil reaction, and electrical conductivity. The soil quality at each sample site was assessed using the indices and data sets, TDS and MDS. Geostatistical techniques and ordinary kriging methods were utilized to map soil quality. Results indicated that the soil quality of rangelands was significantly higher than that of cultivated soils (irrigated and drylands). Additionally, approximately 71% of the soils were classified as very low, low, and medium quality, highlighting the need for monitoring and managing such soils.
S. Ashkevari, S. Janatrostami, A. Ashrafzadeh,
Volume 29, Issue 1 (4-2025)
Abstract
In this study, a conceptual model based on dynamic systems was developed to optimize the management of water, land, and agricultural production (tea and rice) in the irrigation zones of the Sefidroud irrigation and drainage network. To understand the behavior of the network and create a simulation model of the system, a dynamic systems modeling approach was employed, and the simulation was conducted using MATLAB/Simulink. Subsequently, the optimization model of the studied system was developed as a multi-objective model using a genetic algorithm. Various management scenarios were implemented through the weighting of the objective functions. The results showed that selecting the best response from multi-objective optimization models depends on the weighted values of the objective functions, and by changing these values, decision-makers can provide various responses to complex optimization problems. The optimization model determines the cultivated area and water allocation in such a way as to minimize water scarcity and maximize crop performance through different weighting combinations. Furthermore, the findings indicate that the canals of the irrigation network play a crucial role in meeting water needs, and equitable water allocation is essential to prevent excessive extraction and negative consequences, such as saline intrusion and land subsidence. The study demonstrates that the best solutions are contingent upon local conditions and decision-makers' policies. To achieve maximum economic benefits and address water needs, it is suggested to use a weighting combination close to (w1=1,w2=2). Ultimately, this model assists managers and decision-makers in minimizing water scarcity in the region by adjusting cropping levels and optimizing the use of available water resources.
