نشریه رویکردهای نوین در مهندسی آب و محیط زیست
سال دوم شماره 1 (پیاپی 3، بهار و تابستان 1402)

In order to evaluating effects of irrigation with saline-sodic water, we conducted three infiltration experiments in clay-loam soil in end-close furrow. We were using 5cm water depth every week, which had EC=12 ds/m and SAR=32. Experiments were done with volume-index method in end-close furrow in third, sixth and tenth irrigation. Therefore infiltration speed and cumulative infiltrations curves were fitted in different times with Kostiakov and Philip models. Results showed that great decrease in infiltration rate was happened since irrigation with saline-sodic water in experiment. Therefore infiltration rate decreased 40.6 and 68 percent from third irrigation to sixth and sixth to tenth irrigation, respectively. So using saline-sodic water can decreased infiltration rate up to 81 percent in 50 days. Evaluation of the simulation results of test data again Kostiakov &loese and Philip model data with RMSE and MBE parameters showed that these models could simulate soil infiltration rate changes good under the effect of irrigation with saline-sodic water. Also simulation accuracy was increased at the end of experience time than initial and mead time infiltration tests

Population of the world is growing day by day, this will create a situation in which that the water natural resources is becoming limited. According to the classification of the International water Management Institute (IWMI), Iran is one of those countries which by the year 2025 will face a deep major water deficit.There fore, it is clear for us that we must keep in our mind, to use the water natural resources in the best possible manner. Sugarcane is one of the major crops of the tropical and semitropical climatical areas which it has been cultivated in the province of Khouzestan since the ancient times. high share of water use efficiency specially during the warm season growth in this area. The irrigation system for sugarcane crop in this study was the furrow irrigation system. This research project was conducted to varity the effectiveness of the shape furrow irrigation method for the application efficiency of the sugarcane plantations in the province of Khouzestan and the Karun Agro-Industry, Inc with three different treatment depths of 30 Cm, 22 Cm, and 16 Cm respectively, and with three replications to study the above mentioned subject. The three different above mentioned treatments had been shown by the letters A,B,C .For making these furrows for treatments A,B we had used bulldozer (with rotary chain – D6 Model) ; and for making furrows for treatment C, we had used tractor (with high flatation tire – John Deer Model) with a furrower which its’ wings had been modified.

Local scour at the bridge piers is one of the most important factors threatening the stability of the bridges constructed on the rivers. This issue is mainly due to wake and horse shoe vortices. One of the key factors which intensify the local scour depth in bridge pier and usually is not considered is the accumulation of wooden debris in front of the pier. Many bridges have been unstable or collapsed due to this problem. By accumulation of wooden debris in front of bridge piers, the effective flow area around the piers is decreased and hence the flow velocity will be increased which led to increasing of the scour depth to several times of the normal conditions. There are limited relationships or approaches for estimating the scour depth in the case of debris accumulation at the bridge piers. In this study using experimental data of two laboratory flumes and based on the well-known equation of CSU, dimensionless equations have been presented for prediction of the scour depth in the presence of rectangular and triangular wooden debris. The optimum values of the coefficients and exponents of these new equations have been determined using optimization techniques. The modified CSU equation has suitable and acceptable results in both calibration and validation phases. The maximum percentage of error for the proposed equation is 10.1 and 8.4 in calibration and validation phases, respectively. Also, the mean error of this equation is 2.2 and 2.8 percent, respectively.

Numerical Study on Vortices in Collision of Flow with Circular, Square, Triangular, and Pentagonal Barriers of Different DiametersStructures constructed on rivers induce downstream oscillating vortices. These vortices apply oscillating loads on the structure and harm its stability. This paper carried out numerical simulations in SOLIDWORKS to explore the effects of the barrier shape and size on the load applied by the vortex on structures constructed in water streams. It was found that a reduction in the barrier size diminished the vortices. The highest Strouhal number was calculated to be 5.2 at a Reynolds number of 5000 and a barrier diameter of 0.09. The maximum downstream vortices were induced by the triangular barrier, and the maximum Strouhal number occurred to be 7.8 at a velocity of 0.4 and a barrier diameter of 0.05. The maximum vortices induced by the square barrier occurred at a barrier diameter of 0.05. Keywords: Strouhal number, Reynolds number, Barrier, Physical model, Oscillation

The present study was conducted in order to evaluate and compare the quality of underground water resources (springs and wells) in the eastern part of Gorgan Plain in terms of potability and irrigation in a 10-year period. In this research, the results of chemical analysis of 14 wells and 8 springs were used. Water quality index (WQI), Schuler's diagram and some criteria and standards were used to evaluate the quality of drinking water sources. Electrical conductivity, corrosion ratio, magnesium ratio, sodium absorption ratio, soluble sodium percentage, permeability ratio and overall ratio were used in the irrigation section. Then, the zoning of some effective parameters and indicators in each section was done in the GIS environment using the IDW method. Based on the WQI index, the quality of all springs and wells on the edge of the highlands is in the excellent category, but as you move away from the plain, the quality of some wells varies from good to poor. Based on the concentration of some hydrochemical parameters, standards and Schuler's diagram, except for one remaining well, the studied water sources are of suitable quality for drinking. In the irrigation sector, based on the Wilcox diagram, sodium absorption ratio, salinity risk, residual sodium carbonate index and overall ratio, water from wells in the west of the region should be used with caution. In general, the quality of spring water in both drinking and irrigation sectors is much better than well water.

The decline in water level of Lake Urmia is one of the regional environmental crises. One of the measures to rehabilitate Lake Urmia is the inter-basin water transfer from the Zab Basin to Lake Urmia through the Kani-Sib tunnel. The aim of the present study is the hydraulic and hydrological investigation of the water transfer project from Kani-Sib Dam to Lake Urmia. To achieve this goal, the water transfer from the Zab basin to Lake Urmia was simulated in the form of three scenarios (empty reservoir, half-full reservoir and full reservoir) for 10-years period and evaluated hydrologically and hydraulically. Solving the water balance equation with the intervention of the hydraulic relations of the tunnel water transfer flow and dam peak overflow was investigated in the MATLAB software environment on a daily basis. The results of the present study revealed that the outlet of the tunnel will be less than the amount determined in the Urmia lake reclamation headquarters program (600 MCM). It should be noted that the transferable volume of water (with 100% efficiency) in the dry hydrological period (similar to 77-78 year) will be around 190 MCM. In addition, in the case of high water (similar to 82-83 year), the tunnel outlet will be around 767 MCM.

In this study, experiments were performed to investigate the relative energy losses in two models of simple triangular and toothed overflow made of fiberglass in four different landings at three depths of 100%, 90%, and 80%. The effective variables in this study were the landing number and the bottom depth at the end of the hydraulic jump. The results of this study showed that at three downstream depths, energy losses decrease with increasing landing number. Also, energy losses in the free projectile mode are higher than in the other two modes due to the full development of the hydraulic jump. In the general comparison mode, the performance of a toothed triangular overflow is better in energy dissipation than in the toothed mode, due to the fracture and compression of the flow lines in contact with the teeth at the end of the overflow projectile. In general, the use of teeth at the end of the overflow projectile causes energy loss in the conditions of 100% of the bottom depth in the toothed triangular overflow compared to the simple triangular overflow by an average of 7%, and in the conditions of 90% and 80% of the bottom depth by about 8% and 10%, respectively.

The purpose of this study was to investigate CropSyst model accuracy in simulating winter Alvand variety of wheat grain yields under different irrigation regimes. In this study, the CropSyst model was calibrated and evaluated for winter Alvand variety of wheat in the Eghlid region, Fars Province, under different irrigation treatments of 50, 75, and 100% of the field capacity. The agreement coefficient and normalized mean square error of calibrated model using Presley-Taylor evapotranspiration (ET) equation were 0.97, 11.4. The performance of the CropSyst was acceptable. Different irrigation regimes resulted in the difference in product performance and the min performance was obtained from the 50 percent regime. The productivity was different every year and the maximum yield was gained from 100% irrigation regime. Simulation error was minimum at 100% regime. Time of maturity was increased from 100 to 75 and 50% regime. Maximum of dry biomass and performance (ton/hectare) was obtained in 100% irrigation regime, and the minimum was obtained from 75% irrigation regime in the third year, so the performance of 50% regime was more than 75% in the third culture year. It could be from the complicated interaction of water, climate, soil, and plant in different years. The CropSyst can be used for winter Alvand wheat production simulation under different irrigation regimes (with no fertilizer deficit and no salinity).

Drought is one of the main and repeated features of different climates and also one of the environmental events and an integral part of climate fluctuations. Monitoring systems are very important in developing plans to deal with drought and its management, and for this reason, available quantitative indicators are used to express this phenomenon. Since these indices are calculated pointwise, it is necessary to process them spatially. In this regard, mediation methods including geostatistics are used. The analysis and how the meteorological drought changes over time, as well as the ability of kriging, cokriging, image distance weighted (IDW) and radial function (RBF) methods, were evaluated in the spatial analysis of meteorological drought in the entire Karun large watershed. Drought analysis was done using rainfall data from 58 rain gauge stations and 11 synoptic stations with a statistical period of 30 years in the period from 1987 to 2016 using the standardized precipitation index (SPI). Then drought maps were prepared and evaluated. The obtained results showed that the lowest value of the root mean square error (RMSE) related to the cokriging method with a value of (0.32), and the radial function method with a value of (0.34), and this method is considered the best method for the year 2013 is Also, in the year 2008 most stations were involved in very severe drought and year 2000, most stations were involved in severe drought. The results showed that the Cokriging method has higher accuracy than other methods in drought zoning.

One of the most important types of erosion that causes widespread land degradation is gully erosion which has many changes in different climates. In this study, environmental factors such as soil type information layers, Lithology, land use, NDVI, precipitation, Drainage density and distance to drainage and climate type were obtained using GIS for Sarab Halil watershed of Kerman province. Then, using PCA method, the most important environmental factors were identified and finally, using entropy maximum model, the map of the areas prone to gully erosion was obtained using environmental factors. The results showed that the most important environmental factors affecting gully erosion in the study area are climate, lithology, precipitation and soil type. Map of susceptible areas of gully erosion to environmental factors showed that environmental factors in east, south and southeast have more effects on reducing gully erosion and increase to the center of watershed and north and west of the watershed and the effects of environmental factors in increasing gully erosion increase. Meanwhile, the AUC in calibration modes of entropy maximum model was 0.861 and in validation mode was 0.837. Therefore, the entropy maximum model showed excellent ability to predict prone areas to gully erosion and the model is assumed to be excellent.

The main goal of this research is management and comprehensive planning to optimally use the available water resources of Karde dam, using the WEAP model, and supply the demand in the agriculture and drinking sectors, considering the growth of their needs in the future. For this purpose, Karde Dam was first simulated in the environment of WEAP model and the model was implemented for basic conditions and seven different scenarios of development plans. According to the results obtained for the reference scenario, this dam alone does not respond to all the needs defined completely in the horizon of the project, except by applying management measures in the form of scenarios, which will reduce water consumption in different sectors of demand. Among these scenarios are demand management, increasing irrigation efficiency, using both at the same time in one scenario, changing or reducing the cultivation pattern, etc. As a result, by applying the low irrigation scenario and increasing the efficiency at the same time, it is possible to reduce the lack of water demand by 37% compared to the reference scenario, and the reservoir storage volume in this scenario increases by 25% compared to the reservoir storage volume in the reference scenario.

Clogging and blockage of water transmission pipelines is one of the problems that reduce discharge downstream by creating various sediments. The aim of this study was to identify and remove the constraints caused by sediment in the water transmission lines of Sarcheshmeh copper complex to agricultural lands of downstream areas. First, the formed sediment was identified through XRF and XRD experiments and then optimized by using different concentrations of 30, 35, 40, 45 and 50% sodium hydroxide to remove the sediment. The results of sediment analysis showed that the predominant hardened sediment around the inner wall of the pipelines is calcium sulfate. The results of titration of the remaining solution from laboratory reactions also showed that 10 to 21% of sodium hydroxide with a concentration of 30 to 50% is used to separate more than 80% of the sediment adhering to the pipelines, which is 50% in real conditions. Also, the optimal amount of sodium hydroxide in this study was about 35% in 72 hours for complete separation of sediment from pipelines. However, due to the availability of sodium hydroxide with a concentration of 31% in the market and the no need to dilute its higher concentrations in the operating conditions, the proposed amount of sodium hydroxide for the removal of Sarcheshmeh copper pipeline to downstream 31% with an efficiency of more than 87% estimated.