Journal of Irrigation Sciences and Engineering
Year:2019 | Volume:42 | Issue:2 |Papers Count:17

Climate change represents changes in the climate within the earth's atmosphere and its consequences in different parts of the planet. Changes in temperature and rainfall patterns have a great influence on the quantity and quality of water resources, especially in arid regions such as Iran, and consequences of this change on water resources are undeniable. This effect is reported to be on general circulation of the atmosphere, temperature, and precipitation. General atmospheric circulation models are the basis of all studies on climate change phenomena (Su et al., 2016). Because of the large network of these models and the low spatial resolution, some microscopic phenomena in general atmospheres cannot provide an accurate approximation of the climate conditions of the area; therefore, their output should be left to meteorological station’ s micro-scale (Perkins et al., 2007)...

Along with the numerous developments and facilities for constructing large dams, there is a need for developing design and construction methods for systems that can correctly discharge the floods. Weirs refer to any barrier across a channel that raises the flow level and accelerates the flow when flowing over it (Abrishami and Hoseini, 2011). Piano key weirs are the newest type of long-crest weirs and one of the best solutions for modifying the existing weirs. Reducing the energy of the flow over the weirs before their transfer downstream is a solution for preventing possible damage to the structure itself and downstream structures as well as the excess costs incurred by the builders of hydraulic structures due to constructing strong protective structures (Katourani, 2012). Lempè riè re and Ouamane (2003) described the piano key weirs and stated their advantages compared to other conventional nonlinear weirs as the ability to place the weir in the crest of the reservoir dam and thus increasing the specific flow rate. Erpicum and Machieles (2011) compared the energy dissipation between two different geometries for a piano key weir and a spillway weir. Concerning the application of a block, the tests and results obtained by the US Land Renewal Organization indicate that using large blocks that separate the flow jet and create turbulence can effectively dissipate the kinetic energy of the current...

Flood is one of the most dangerous and destructive phenomena which endangers people’ s lives and properties all around the world. According to statistics of a 30-year period (1974-2003), about 2162 major floods have occurred which constitute 34% of the world's disasters (Tajbakhsh and Khodashenas, 2012). Floods are frequent and ruinous in Iran due to severe weather condition. Several factors intensify the risk of flood in urban areas including urbanization, land use changes, inappropriate drainage systems, and impermeable area development (Sabeti, 2011). Likak has faced numerous floods due to high rain density, high rate of urban development, unsafe and unproductive urban development, ignoring safety criteria in developing urban areas, road watering issues, inefficient drainage systems, and inefficacious water channels. Water channels and drainage issues have never been evaluated in this town. Applying an effective runoff management plan is the ultimate solution for the problem of flood in Likak. Storm Water Management Model (SWMM) is one of the most reliable and prevailing models for evaluating and managing the urban runoff issue. SWMM is a dynamic rainfall-runoff simulator which can be used for simulating the quantity and quality of the run-off for a single raining event or continuous long-term rains (Gironas et al, 2010). Yu et al. (2014) adapted and calibrated SWMM to Jinan, a typical piedmont city in China. Fourteen storms were used for model calibration and validation, finally verifying large-scale applicability of the model to piedmont cities. Results of this study verified that SWMM is applicable to large-scale cities....

Scarcity of water resources in the entire country is more serious in the northern provinces like Golestan. Therefore, farmers have to use saline water or waste waters. One way to adapt to this condition is to use unconventional water such as Caspian Sea water, with lower salinity as compared with water from free seas, for common crops like soybean. Thus feasibility of using Caspian Sea water that has integrated with narrow common water and the calibration of Aquacrop model under the effect of salinity and water stress for soybean crop in Golestan province are more important. The Aquacrop model assumes a linear relationship between the biomass yield (BY) and crop transpiration one one hand and water productivity (WP) value on the other (Steduto and Albrizio, 2005). This model, as compared to other crop models, requires minimal input data and its new version 4. 0 (June, 2012) has a salinity module which was used in this research to simulate the grain yield (GY) and WP of soybean under deficit and saline water irrigation. Furthermore, the AquaCrop model has not often been tested to simulate the yield of soybean under saline conditions in the semi-arid climate of Golestan province. This study aims at evaluating the efficiency of AquaCrop model in soybean yield simulation. The results are to be used for optimizing water consumption under water and saline stress. To this end, an experiment was carried out at the research farm of Gorgan University of Agricultural Sciences and Natural Resources...

Water scarcity is a major constraint in the development of rice farming in some parts of the world. In many areas, the volume of water consumed in the field and during the growing season of rice is usually more than the actual requirement due to traditional flood irrigation. In the province of Khuzestan, irrigation water requirement is potentially high due to the coincidence of rice cultivation with the beginning of hot months of the year. In traditional irrigation management, regular water entry and exit from the basins is commonly used to reduce water temperature and create a cool environment for plant development. This system causes a lot of water losses. It seems that a change in the irrigation method of rice fields is necessary. The application of new technologies, such as pressurized irrigation systems, can be an appropriate approach to reduce future problems related to increasing water shortages. In this regard, the study of pressurized irrigation systems has been considered as one of the strategies for reducing water consumption and increasing water productivity in rice cultivation in the research program. Result of a research in Pakistan about water use efficiency and economic feasibility of growing rice with sprinkler irrigation showed that the application of this system increased the yield of rice by 18%, while the water consumed was 35% less than the traditional irrigation system (McCauley, 1990)...

Today, the problems of water scarcity, limited water resources, high volume of evaporation, and water losses have highlighted the importance of ways to reduce the rate of evaporation from small and large reservoirs. In order to increase water supplies, reducing losses through evaporation have been investigated both in theoretical aspects and in practical applications in a number of countries (Ali et al., 2011; Barnes, 2008; Coleman, 2000). One of the most important methods for water conservation is the application of chemical films for reducing evaporation from open water resources such as reservoirs, lakes, and the like (Craig et al., 2007). These applications are especially important in arid and semiarid areas for the purpose of reducing evaporation rates from water surfaces. Most materials suggested by researchers for reduced evaporation have been the fatty alcohols containing 14 to 22 carbon atoms, such as Tetradecanol (C14), Pentadecanol (C15), Xadecanol (C16), Heptadecanol (C17), Octadecanol (C18), Nonadecanol (C19), Eicosanol (C20), Heneicosanol (C21), and Docosanol (C22). The two most favoured compounds used for evaporation control are Hexadecanol (C16H33OH) and Octadecanol (C18H35OH) although more complex variants are currently in development since they offer high resistance to water evaporation. In fact, small flakes of the solid alcohol spread spontaneously to form monolayers with a high molecular packing density (Manges and Crow, 1966). In this study, a new chemical method has been used to reduce the rate of evaporation. A new combination is made from polyvinyl butyral resin and Hexadecanol and Octadecanol as two fatty alcohols to reduce of evaporation from surface water sources and wastewater tailings dam of Sarcheshmeh Copper Complex...

The explorers consider the study of water flow in saturated and unsaturated soils to determine the seepage, pore pressure, uplift force, and hydraulic gradient in the design of dams. Numerical simulation is a rapid low-cost method for the study of soil water flow, which has recently been increased. Many investigators have described approximate methods, based on Dupuit assumptions, to locate the surface of seepage and seepage discharge for different tailwater positions. In order to reduce the seepage discharge and, consequently, flow energy reduction passing the dam, various actions such as the construction of clay core, trench and grout certain, and clay cover on the reservoir floor have been considered. Despite all the measures taken to prevent the movement of water in the embankment dam, water always penetrates the downstream parts due to the permeability of the materials. Drainage systems are designed to collect and direct seepage of water to downstream areas, keeping the dam’ s riffle slope dry to decrease the hydroscopic pressure and increase the stability of the embankment dams. Horizontal drains are widely used in homogeneous embankment dams with an average height. In this study, Richards equation was desecrated in two-dimensional and unsteady conditions using an unstructured triangular finite volume algorithm and a computer model developed to simulate seepage in saturated-unsaturated soils. In this model, Van Genuchten equation or other functions can be used to calculate hydraulic conductivity in unsaturated soil for the simulation of flow...

Nowadays, the world is facing increasing population and demand for food as well as shortage of fresh water supplies (Mangus et al., 2016). Deficit irrigation (DI) and urban wastewater utilization are two management solutions for the purpose of reducing fresh water consumption in agriculture. Due to the shortage of irrigation water resources and the increase of the area under cultivation, farmers in the northern part of Isfahan (viz., Borkhar), Iran, employ these two strategies. Precise irrigation planning could be of help in preventing water stress and optimum performance in plants. Water stress is considered one of the most important plant stresses, which is the most common and limiting factor for yield (Jackson et al., 1981; Scherrer et al., 2011; Zia et al., 2013). Since 1970, canopy temperature has been accepted as an indicator of water stress because plants under stress close their stomata for preserving water and reducing stomatal conduction, decreasing transpiration, and increasing leaf temperature (Ballester et al., 2013). One of the most reliable indicators is the crop water stress index (CWSI). Several studies have been conducted on irrigation scheduling using leaf surface temperature measurements. (Candogan et al., 2013; Orta et al., 2003). The difference in air temperature and leaf area was calculated from the difference in vapour pressure for different irrigation treatments in soybean and watermelon plants. Also, sorghum was studied by O’ Shaughnessy et al. (2010) in different irrigation systems and the crop water stress index (CWSI) was calculated. Mangus et al. (2016) examined the water stress index of corn in four stages of plant growth; their results showed that in the third stage of corn growth (i. e., in the flowering stage), the surface temperature of the leaf was higher and that the plant used the most energy for cob growth and thus shrinking transpiration from the plant. Based on the aforementioned studies, this study sought to compute the water stress index (CWSI) under irrigation treatments in the climate of North Isfahan in order to identify the irrigation time...

The separation zone in the entrance of intake channel has no effect on flow discharge but it reduces the effective cross-sectional area of the intake, as well as the bed load, which enters the intake due to low velocity flow deposits in this area. Therefore, knowing the dimension of the separation zone in the lateral intake is very important. One of the methods to control sediment transport to a lateral intake is to use submerged vanes in front of an intake mouth. Azizi et al. (2012) evaluated the effect of cuts on the leading edge of vanes on local scour and the performance of submerged vanes in lateral distribution of sediments. Abbasi and Maleknejad Yazdi (2014) carried out some researches about the impact of sill and submerged vanes on sediment laden flows at lateral intake in straight channels. According to the results, the dimension of the separation zone depends on intake ratio and intake angle, and the effectiveness of froud number in the main channel is negligible. In the present study, different shapes of submerged vanes used in Azizi et al. ’ s (2012) study were employed to measure the dimension of the separation zone in a bend-shaped flume and the obtained results were compared with the results of Abbasi and Maleknejad Yazdi’ s (2014) studies...

The yield of rainfed crops depends on climatic parameters, plant genetic characteristics, soil type and agricultural operations (Hosaini et al., 2007). Among these factors, climatic variables have a stochastic nature. Therefore, it is important to investigate the effect of the mentioned parameters on the variability of the crop plants yield. The correct identification of the climatic conditions will help farmers to timely sow and supply plant requirement during the growing season (Azizi and Yarahmadi, 2003). Also, predicting the yield of strategic plants (such as wheat) will be possible via identify and quantify the effects of the important climatic variables on crop production in each region (Bazgeer and Kamali, 2008). Kurdistan is one of the most important rainfed agricultural regions in Iran. Bijar, with a production about 123, 000 tons of rainfed wheat per year, is one of the most important regions to product rainfed wheat in Kurdistan. The maximum and minimum yield of rainfed wheat in Bijar during a 25-year period has been between 1380 and 213 (kg/ha), respectively (Anonymous, 2015). This large range of yield changes has had a significant impact on the region's economy. The present research was carried out with the aim of identifying important climatic factors in Bijar region and developing a model for estimating rainfed wheat yield based on these factors. The results of this research can be useful in developing quantitative and qualitative agricultural products and sustainable use of resources...

Increased production per unit volume of consumed water requires more precise planning in selecting the appropriate irrigation method for the optimal use of available water resources in the agricultural sector. The province of Khuzestan has been ranked third with 13. 8 percent of the total date production of the country. Therefore, using pressurized irrigation methods with the goal of optimal utilization of water resources is inevitable. This research was carried out with the aim of investigating the possibility of utilizing subsurface drip irrigation systems in date orchards and determining the most suitable irrigation treatments in terms of yield and water use efficiency for Kabkab cultivar. Mohebbi and Alihoori (2013), in a study conducted with four irrigation treatments including surface irrigation and drip irrigation with 75% and 100% cumulative evaporation of class A evaporation pan in Hormozgan province, showed that despite different amounts of water in treatment irrigations, there was no significant difference in fruit yield, vegetative traits, and shading surface. The highest and lowest water use efficiency was obtained from drip irrigation treatment with 75% water and surface irrigation treatment with water content equal to 100% cumulative evaporation from class A evaporation pan. Therefore, irrigation with drip irrigation method and 75% cumulative evaporation from class A pans were recommended for irrigation of palm groves. The results of Mohebi’ s (2005) study on comparing the effects of two equivalent amounts of water, 75% and 100% evaporation of class A pan in two methods of drip irrigation and surface irrigation on the growth and development of the palm cultivar Peeyaram showed that, among different treatments, there were significant differences in vegetative growth indices such as the number of leaflets, the trunk diameter, and the shading surface...

using mathematical programming models for determining appropriate cropping patterns has recently attracted a lot of attention. The agricultural sector is one of the most important and powerful economic sectors of the country. In the last ten years, its contribution to gross domestic product has been around 18% on average. The method of linear programming has been widely used in the fields of land allocation and determination of optimal cultivars since the 1960s. The purpose of linear programming is to maximize or minimize the objective function by considering a number of constraints and decision variables simultaneously. Fuzzy scheduling allows decision-makers to interfere with non-explicit data and data parameters in models. Compared to other models of math planning, it is more applicable and more flexible to be used in optimization problems and in determining the optimum crop cultivation patterns. Moreover, the results are more reliable (Rastegaripour and Sabouhi, 2009). Mir Karimi et al. (2016) investigated the optimal cultivar pattern in the city of Amol using the ideal planning and taking into account the goals of reducing fertilizer use by seven percent. Their results showed a one-percent reduction in pesticides to protect the environment and a reduction of 93% of water use for the conservation of scarce water resources and sustainable agricultural development. In this study, a fuzzy utopian planning model with three equal weight patterns, different weights, a decreasing weight and an incremental weight for ideals and water resource constraints are designed, taking into account environmental and economic objectives. The main objective of this research is to optimize water and land resources in Hamadan province. First, we introduced a weighted fuzzy goal programming model (WFGP). Using this model, optimum cultivating model for farmers in Hamadan was determined, considering their income goals, environmental goals and sustainability of water resources of the region. Subsequently, the allocation between irrigation water inputs and land surface was calculated considering equal weights, different weights and different decreasing weights for the desired goals...

Due to the climatic conditions of Iran, the limitations of irrigation resources, and low irrigation efficiency in traditional methods, on the one hand, and the existence of arenas for the development of blue land and the increasing need for food, on the other, application of pressurized irrigation methods as one of the most effective ways to optimally use existing water resources is inevitable (Baradaranhazave et al., 2006). In recent years, the methods of irrigation under pressure, especially the classic sprinkler irrigation with travelling sprinklers have, in general, been used in Fars province, and in the city of Eghlid, in particular. The purpose of the present study was to determine the efficiency of the system after the implementation of the system, the maximum irrigation efficiency of the system, and its difference with the amount available in field conditions...

One of the important issues in assessing climate change using the output of General Circulation Models (GCMs) is their uncertainty so that the outputs of a model in a region may vary with another model in the same region. Disregarding the uncertainty of these models reduces the accuracy of the final outputs (Ashofteh and Massah, 2012). Various methods have been developed to analyze and reduce the amount of uncertainty. Among the methods used to investigate the uncertainty of the output of GCMs, one can mentioned the weighted means of observation, Wilcoxon Signed Rank test, Bootstrap confidence-interval estimation technique, Box Plot method, and the cumulative frequency distribution function. Accordingly, the present study, while predicting the temperature, precipitation and drought variables in Golestan province for the future 30 years via two general circulation models including ECHO-G and HadCM3, examined the uncertainty of these models by weighted means of observation and Box Plot methods. Also, statistical analysis of data by analysis of variance and mean comparison tests are among other goals of this research...

To control scour, it is first necessary to examine the scouring mechanism and the flow patterns around the abutment. By constructing of the abutment, the approaching flow pattern around it is disturbed. In addition, this brings about an increase in the average flow velocity due to narrowing, and the three-dimensional patterns of the flow are formed around the bridge abutment, which is the main cause of the local scour around the structure. To protect the bridge from scouring, two measures have been developed in the past; a) the direct methods and b) the indirect methods, which modify the flow pattern and reduce the power of vortex vortices. One can mention the use of roughness, sluts, submerged vanes and immerse vanes. One of the problems in using submerged vanes is the scouring formed around these structures because these vanes are placed on the bed and the three-dimensional patterns around them form and cause the scour around the vanes and eventually lead to their destruction. On the contrary, immerse vanes are located above the bed and their destruction from bed scouring is impossible. Application of immerse vanes was first studied by Shafai-Bejestan et al. (2016) in order to control the scouring of the outer river banks in a 180 degree flume bend. Their results showed that by installing the immerse vanes on the outer bank of the bend, the amount of scour depth decreases in the area of the outer bank toe. On the other hand, the use of these vanes to control the scour of the bridge abutments has not been studied so far. Therefore, the present research has been carried out. In this study, the immerse vanes with four different distances, each with four different flow conditions, were tested to determine the most appropriate distance between the plates...