فصلنامه علوم و مهندسی آبیاری
سال چهل و هفتم شماره 4 (زمستان 1403)

In order to compare of WinSRFR and SIRMOD software in simulating furrow irrigation performance, a field experiment was carried out in the Jayedar Plain. Five different furrow irrigation methods including conventional furrow irrigation (CFI), surge irrigation with on/off cycle ratios of 1 and 0.5 (SFI1-1 and SFI1-2, respectively), fixed alternate irrigation (FFI) and variable alternate irrigation (AFI) were investigated. A total of 15 irrigation evaluations were performed at the initial, middle, and end of the growing season by measuring inflow rate, cutoff time, outflow rate, infiltration and advance time. The length and spacing of experimental furrows were 120 and 0.75 m and the inflow and cutoff times at the initial (3rd irrigation), middle (6th irrigation), and end (9th irrigation) were 0.28 L/s and 240 min, 0.42 L/s and 360 min, 0.35 L/s and 300 min, respectively. The WinSRFR 3.1 and SIRMOD software were calibrated, assessed, and compared using field measurements based on the zero-inertia model. WinSRFR and SIRMOD softwares demonstrated a strong correlation between the measured and simulated values of runoff, infiltration and advance time (coefficient of determination of (0.9984, 0.9976), (0.9908, 0.9932 ) and (0.9449, 0.9331), respectively. The relative error values of WinSRFR and SIRMOD Software in estimating runoff, infiltration and advance time were (2.96, 3.15), (3.03, 3.30), (2.09, 2.46) respectively. Both software overestimates the runoff (λ=1.0296 in WinSRFR and λ= 1.0315 in SIRMOD) and the advance time (λ=1.0209 in WinSRFR and λ= 1.0246 in SIRMOD). The WinSRFR software underestimates infiltration (λ=0.9697) but SIRMOD software overestimates infiltration (λ=1.0333). The results of this study show that AFI is a more suitable method for maize irrigation in the study area. The WinSRFR software has an advantage over the SIRMOD software in simulating furrow irrigation performance due to its higher ability and the use of a wide range of input parameters.

Groundwater is one of the most important sources of freshwater supply in arid and semi-arid regions. The purpose of this research is to investigate the chemical quality of Kabul's groundwater using statistical description methods, statistical classification, quality indices, graphical methods, and also to examine the spatial variations of effective physicochemical parameters of 54 bore wells water using geostatistical methods with the help of GIS tools. The chemical quality evaluation shows that due to the influence of rivers on Kabul's groundwater, a large part of the city's groundwater quality is of the Mg-  and Mg-Ca-  types, which is considered inappropriate for industrial use based on the International Association of Hydrogeologists method . The United States Salinity Laboratory diagram shows that the groundwater in this city is in the average range, C3S1, and in some cases good and inappropriate for agricultural and irrigation purposes. In terms of drinking, according to the Schuler diagram, water quality is salty the groundwater in the region is categorized as brackish for drinking purposes, with moderate conditions in some areas. The spatial variations of key physicochemical parameters influencing the quality of Kabul's groundwater were analyzed using various interpolation methods. Then, using the mutual evaluation criterion, the best variogram model was selected to draw the estimation map. The results show that for the zoning of EC, TH, TDS, , , and  parameters, the inverse distance weighting method, and for , ,  the indicator kriging method were appropriate. The estimation maps of the spatial variations of effective parameters on Kabul's aquifers show that the groundwater quality is moderate towards the west of Kabul and becomes suitable as it progresses towards the west. In contrast, the quality of groundwater decreases from the center of the city towards the east, and the salinity of the water has increased.

This study investigated the optimal management and allocation of irrigation water under different flow scenarios focusing on economic water productivity (EWP) index.  In this study, the aim was to allocate and distribute water between networks and lower crops of Maroon reservoir dam The multi-stage stochastic programming method was used to develop the optimization model under three scenarios of arid, normal and wet years in two management modes and the results were compared with the traditional management figures. For this purpose, hydrometric data was sourced from the Marun network station for the 2006–2016 periods. Finally, the results of the second run provided a better irrigation program with a 19% increase in the total area under cultivation  and a 7% increase in objective function profit. Moreover, the highest mean EWP in the three scenarios was obtained in the second run for the North network at 9% more than the first run.

The stability and flow rate of earth dams are influenced by several factors, including geometric characteristics, material permeability, and the height of water upstream. To effectively understand the behavior of unsaturated soils in earth dams, it is essential to apply the principles of unsaturated soil mechanics, given the complexities involved. Neglecting uncertainties in geotechnical assessments can lead to incorrect estimates of safety factors for dam slope stability. This research investigates the impact of unsaturated soil conditions on seepage discharge and the safety factor for the downstream of the earth dam under varying scenarios, with a focus on the Seydon Dam in Khuzestan province, Iran. The findings indicate that modeling the dam's soil as a saturated-unsaturated system decreases the computed flow rate through the dam and enhances the downstream slope's safety factor in both probabilistic and deterministic analyses. Additionally, a sensitivity analysis reveals that the earth dam shell's parameters significantly influence downstream slope stability. Spatial variation analysis further indicates that accounting for spatial changes in soil parameters can decrease the safety factor of the downstream slope compared to a standard assessment.

Today, in many parts of the world, water and soil resources are facing the threat of salinization. Several researches has been done for the desalination of water and soil resources. One of these proposed solutions is leaching. There are several leaching methods which should be studied for each area. The present paper studies the saline soil of Nazarabad area, Iran using two types of saline and conventional water of the region and three different volumes of water (one, three, and five times the pore volume) in both continuous and alternate modes under frozen and non-frozen conditions with three replications. Then, the movement of salt was simulated by the MACRO model. The amount of salinity in drain water was measured during the experiments. The results showed that the conventional water managed to reduce soil salinity and solute concentration in the leaching experiments. Accordingly, the frozen treatments continuously irrigated with conventional water outperformed other treatments in terms of achieving minimum soil salinity (ECe<1 dS/m). Similarly, less water can be used in these treatments to reach the minimum ECe according to the irrigation scheduling predicted by the MACRO model i.e. 3.5 pore volume. At last, it was found that these soils did not require CaCl2 for correction.

The transport of sediment in rivers is a crucial aspect of hydraulic engineering and environmental management. This study focuses on suspended sediment transport in the Balaroud River, a significant tributary of the Dez River in northern Khuzestan Province, Iran. We evaluated various sediment transport equations, including those by Rouse (1937), Lane & Kalinske (1941), Brooks (1958), Bagnold (1966), and Yang (1996), to determine the most accurate model for estimating suspended sediment load in this river. Data spanning from 2007 to 2020, collected from the Khuzestan Water and Power Authority (KWPA), were analyzed to compare these models against measured sediment loads. The Rouse method proved to be the most reliable, achieving approximately 80% accuracy in estimating suspended sediment load. The modified Yang equation followed with about 60% accuracy, while accuracy for Brooks' method was around 49%. Conversely, the Bagnold (1966) and Lane & Kalinske (1941) models demonstrated significantly lower accuracies of 21% and 12%, respectively. The study reveals that Rouse and Yang equations align better with the Balaroud River's conditions, marked by its sandy substrate and the influence of the Balaroud dam on flow dynamics. The findings underscore critical discrepancies among the evaluated equations and the necessity for case-specific assessments to enhance sediment transport predictions. This research highlights the importance of selecting models tailored to the unique characteristics of each river system for effective sediment management and environmental conservation. Recommendations include prioritizing the Rouse equation for similar rivers and pursuing further research to develop models suited to diverse sediment transport dynamics.

Side weirs are important components in irrigation and drainage systems, used for controlling and diverting flow. Given the advantages of side weirs in converging channels, improving the hydraulic performance of these structures is essential. This study aims to enhance the hydraulic performance of converging side weirs through the installation of a side vane. Numerical simulations were conducted using the Flow-3D software with various turbulence models, and the results were validated against experimental data ( ). In this study, three different angles for side vane installation (60, 90, and 120 degrees) at two positions, upstream and downstream of the weir, were investigated. The results showed that installing the side vane at the upstream position of the weir with a 60-degree angle led to a 32% increase in the diversion flow compared to the control scenario (without side vane). The analysis revealed that the reduction in flow velocity downstream of the side weir and the creation of a low-velocity zone around the side vane contributed to more effective flow guidance toward the weir, thereby increasing its efficiency. The practical application of the results of this research is the improvement of converging side weir design and their enhanced efficiency in managing water flows.

Different interpolation methods, each with their own strengths and weaknesses, are used to temporal and spatial estimation of precipitation. The accuracy of this estimate depends on the density of point data measured at rain gauge stations. In this study, the effects of the rain gauge network density on the accuracy of different interpolation methods were investigated in producing a monthly precipitation zoning map for the Samian catchment in Ardabil, Iran. The effectiveness of Bayesian Kriging, Completely Regularized Spline, Local Polynomial, Inverse Distance Weight, Ordinary Kriging, Ordinary Co-Kriging, Simple Kriging, Simple Co-Kriging, Spline with Tension, Thin Plate Spline and Universal Kriging interpolation methods was evaluated in two gauges density scenarios using evaluation criteria over 2011-2013. It was found that Inverse distance weight and Bayesian kriging methods had the best performance for the first scenario with high gauge density (16 Stations) and the second scenario with low gauge density (11 Stations), respectively. Moreover, analysis of variations in indicators across scenarios revealed that reducing the rain gauge network density by 30% improved evaluation metrics in only 40% of cases. Bayesian Kriging and Completely Regularized Splines were introduced as the preferred methods for improving evaluation indices change, and Local polynomial and simple co-Kriging methods were selected as the superior methods for improving evaluation indices quantity.