Journal of Irrigation Sciences and Engineering
Year:2020 | Volume:42 | Issue:4 |Papers Count:16

Groundwater is the main source of potable water for more than 1. 5 billion people throughout the world, including arid and semi-arid regions like Iran. Literature review showed that there is no use of the dimensional similitude and physical modelling for estimating seepage from channels and its effect on the groundwater, yet. Thus, in order to better understand this phenomenon, the current study aimed at investigating the effects of infiltration and seepage on the groundwater recharge at different water level depths. Numerous studies have been conducted to assess the groundwater recharge, such as Yin et al. (2011) that utilized some methods such as the water table fluctuation method and the Darcian flux and water balance method in China. Similarly, using data from some irrigation projects and piezometric level data, Ochoa et al. (2013) evaluated the effects of seepage on the groundwater recharge in New Mexico. Moreover, Demlie (2015) compared the water balance method and the chloride mass balance method to quantify and investigate the groundwater recharge in Ethiopia. In the current research, the earth channel of Boldaji with loamy soil, located in Borujen city, Chaharmahal and Bakhtiari province, was chosen as the prototype. The dimensions of such a channel were transmitted to laboratory models at soil mechanics lab at Shahrekord University. Using dimensional similitude equations, 9 discharges (40-161 l/s) and 4 water-table depths (0. 75, 0. 8, 0. 85 and 0. 9 m from soil surface) were converted to the applicable discharges of the model. The results of the laboratory physical model showed that the infiltrated water raised the groundwater 3. 5-11 cm. The values of recharged groundwater were, in turn, calculated by means of water balance method and the results showed no suitable estimates of such a method for the trapezoid and triangle crosssections...

Introduction Infiltration is considered as one of the most important soil parameters in the design and evaluation of furrow irrigation systems. Water is infiltrated through the wetted perimeter when it reaches a given point in the furrow until it recedes. The depth of infiltrated water at a given point, therefore, is a function of opportunity time, wetted perimeter, and soil intake characteristics (Oyonarte et al., 2002). Thus, in-depth knowledge of how the initial (e. g. initial water content) and boundary conditions (such as water head and wetted perimeter) of a furrow can act on the infiltration process is essential. Previous studies show that cumulative infiltration in furrow irrigation is highly affected by the water head and initial water content. In furrow irrigation, water infiltration into the soil is two-dimensional, both vertically and laterally (Bautista et al. 2014). Gravity forces are dominant in vertical infiltration, while suction forces dominate horizontal/lateral infiltration. Suction forces largely depend on soil matric potential, which is a function of the soil texture and structure, and play an important role in soil moisture retention, sorptivity, essential for plant growth, and lateral infiltration. Knowledge of lateral infiltration and edge effect is essential for designing furrow irrigation systems because many researchers have found that more than 60% of total infiltrated water is through the side walls of furrows. Several studies have been carried out to determine how initial and boundary conditions may affect the cumulative and lateral infiltration in furrow irrigation, but the combined effect of water head and initial water content on infiltration process is not investigated yet. Therefore, the main objective of this study is to investigate the combined effect of various initial (i. e., irrigation interval or initial water content) and boundary (i. e., water level or the wetted perimeter) conditions on the cumulative and lateral infiltration...

Introduction Awareness of the important moisture points is crucial for irrigation studies on the farm, but measuring this information in a direct way is very costly and time consuming. Therefore, several models and relationships have been developed as Pedotransfer functions which indirectly predict the hydrological properties of the soil using readily available soil data with the aid of a series of proper mathematical relationships (Nguyen et al., 2015). Since the measurement of important moisture points is a time consuming, costly and difficult work, many attempts have been made in order to use simpler soil properties such as texture, the amount of organic matter, and bulk density. Pedotransfer functions are indeed predictive functions which establish relationship between the soil’ s readily available and latency data (e. g., the percentage of sand, silt and clay, bulk density and organic matter) including the parameters of the moisture curve (field capacity and permanent wilting point) (Botulla et al., 2013). Moreover, the functions that can be successfully implemented in an area may not have suitable adaptations in another area with real values. There are several methods for obtaining Pedotransfer functions, among them are linear regression (LR), artificial neural networks, fuzzy adaptive-neural inference, and support regression vector...

Introduction Rainfall is among the most important climatic factors affecting the rainfed cultivation. Thus, in order to maintain water consumption in current agriculture, with the view of water resources management, the country needs to convert some irrigated land areas to rainfed cultivation in the near future. Indeed, it is necessary to conduct an analytical study on rainfed agriculture and identify appropriate areas for rainfed agriculture in the country, especially in Urmia Lake basin. Principal component analysis (PCA), K-Means and Ward have been already used to assess climate regionalization in different regions such as Spain (Diaz and Rodrigo, 2004), Greece (Kitsara et al, 2005), central-northeastern region of Mexico (Pineda-Martinez et al, 2007), Luanhe basin (Hassan and Ping, 2012) and Iberian Peninsula (Parracho et al, 2015). This study was, thus, intended to study the regionalization of the eastern part of Urmia Lake basin on the basis of the precipitation and yield of rainfed wheat using PCA, K-Means and Ward methods. To that end, the maps were drawn in the GIS environment and three methods of clustering were compared. Finally, using the clustering of precipitation and rainfed yield, wheat cultivability was investigated in the eastern part of Urmia Lake. To that end, the daily rainfall dataset of 26 rain gauge stations were used and the yield of rainfed wheat was considered during the period. Then, PCA, K-Means and Ward clustering were performed and the results were compiled. The homogenousity of the resulting clusters were analyzed by H and S statistical tests and homogeneous clusters were drawn in the GIS environment. The analytical factor coefficients to the main components, through K-Means clustering method, showed that the clusters point of view, precipitation and rainfed yield were more consistent and the results were close to each other...

Introduction Iran is the fourth world producer of figs with an average of 75, 833 tons from 1993 to 2013 (FAO, 2016). Estahban area provides about 90% of dried fig in Iran (Jafari, Abdolahipour-Haghighi and Zare, 2012). The rainfed fig orchards in this area have been extremely affected by severe drought in recent years, leading to 10% to 80% reduction in fig trees and fruit in 2010, respectively (Jafari, Abdolahipour-Haghighi and Zare, 2012). For this reason, the tendency to apply supplemental irrigation in Estahban fig orchards has increased in previous years. However, the lack of information about the amount, timing, and application position of supplemental irrigation to achieve efficient use of water in this area makes it difficult to deal with this issue in the study area. The main objective of this study was, thus, to investigate the effect of different amounts and times of supplemental irrigation at different distances from tree trunk on soil water variation, quantity of fruits, and fig growers’ income under drought conditions...

Introduction Bridges constructed across rivers are among the most important structures, especially during and after flood events. Bridge piers are exposed to some hazardous factors such as local and contraction scour hydrodynamics. The lower prediction of maximum scour depth can cause bridge failure, while over-prediction leads to a very costly project. The appropriate estimation of maximum scour depth around bridge piers is, thus, necessary. In some bridges, more than a single pier is considered during the design phase, and the interaction between the adjacent piers makes the situation very different. The flow structure and scour process around a group of bridge piers are, indeed, very different from a single bridge pier. Many researchers have studied the scour around single and/or multiple-column bridge piers. For instance, studying the scour depth for a group of piers, Mahjub et al. (2014) reported that the maximum scour depth around the second bridge pier was less than that of the upstream pier, while the scour depth around the third pier was lower than that of the first and second piers. Moreover, Daneshfaraz et al. (2014) investigated the effect of pier slots on the maximum scour depth around the two-column bridge piers. The results that the slot reduced the maximum scour depth compared to the piers without a slot. In this paper, the flow and bed topography around a group of piers was studied experimentally...

Introduction Khuzestan plain as one of the fertile regions in Iran is suffering from some problems such as soil salinity and water deficit. The most important irrigated crop in Khuzestan is wheat and its average yield in the southern parts of Khuzestan reaches 2 to 3 t ha-1, . Irrigation management and optimal conditions, however, should be provided to reduce both water and salinity stresses in the crop yield in the region. To introduce the best irrigation schedule for wheat in the study area, we applied the AquaCrop model to simulate the irrigation scheduling for the crop. The aims were to (1) calibrate and validate the model, (2) determine the appropriate irrigation scheduling for wheat to improve water productivity and increase grain yield, and (3) also evaluate the performance of the model...

Introduction Being vulnerable to food shortage, tomatoes are dependent on nitrogen fertilizer for their growth and crop yields (Zomorrodi, 2006). In effect, there is a close relationship between the amount of nitrogen fertilizer consumed and the accumulation of nitrate, which poses a threat to consumer health (Mousavi Fazl, 2005). The accumulation of nitrate in tomatoes has a considerable negative effect on its quality and increase the amount of toxic substances in tomatoes (Malakuti et al., 2005). The results of many studies show that the appropriate combination of nitrogen fertilizer treatments and the irrigation regime in such a way that the plant encounters a certain level of water stress during a particular period or throughout the growing season may lead to the maximum efficiency of water usage in the plant (Bagheri et al., 2016). Zomorrodi (2006) examined the effect of deficit irrigation on the quantitative and qualitative characteristics of tomatoes. The results showed that the effects of irrigation water on vitamin C, acidity and soluble solids were significant. Khorramian (2015) also studied different levels of drip irrigation with the supply of 40, 70 and 100% water requirement on the yield and water use efficiency in tomatos. The findings of this study showed that maximum yield was obtained from drip irrigation with 100% water level, while 40% water level treatment had the highest water use efficiency.

Introduction Reduction of water resources in arid and semi-arid areas requires the application of management methods to achieve optimal performance. With the logical application of saline water as a source of irrigation water, we can supply a part of the crop water requirement (Hamdy, A., Abdel-Dayem, S. and Abu-Zeid, M., 1993), using various applicable management techniques. The optimal management is, in turn, considered as the use of conjunctive irrigation. Two commonly used solutions include mixing salty and fresh water to obtain water with the optimal salinity; and also the periodic application of fresh and salty water (Amer, 2010; Aslam, & Prathapar, 2006). In effect, salt mainly enters the surface layers of the soil through irrigation and the solute moves vertically from the unsaturated to the saturated zone and towards the groundwater. In turn, the SWAP model is often used to simulate the solute transfer in soil. However, field measurement of the solute concentration changes is very difficult in soil profiles. A simulation model can, thus, be used to estimate the accumulation of solutes in the soil profiles. (Van Dam, Huygen, & Wesseling, 1997)...

Introduction One of the most important problems arising after the construction of a dam is sedimentation in the dam’ s reservoir. In turn, one of the phenomenon that may affect the sedimentation is density currents. A density current is, indeed, the movement of a fluid through another one that has a different density. If there was saline stratification in the vertically downward direction in the reservoir of the static fluid, density current occurs as interflow. Kao (1977) derived the flow diffusion velocity along a common surface between two homogeneous fluids based on Bernoulli's theory. Likewsie, Ungarish (2012) and Sahuri et al. (2015) conducted studies on the interflow density current...

introduction Rainfall is the main motivator in the hydrologic cycle of the basin and it is an element of meteorological phenomena undergoing severe changes in time and place. The suitability of density and distribution of rain gauges in the rain gauge networks of each area is an effective step in the success of the water plans, regional projecting and effective use of the information (Karamouz et al., 2010). Many researchers have shown that the geostatistical prediction method provides better estimates of the regional rainfall than the traditional methods. Tanaka and Putthividhya (2013) used the geostatistical method to assess the quality of the rainfall estimation in the Basin of Chao Phraya. They tried to calculate the difference between the rainfall data and the results obtained from the above methods by plotting Thiessen Network and the co-ordinate lines by nverse Distance Weighting and Ordinary Kriging methods. They also examined the correlation between the height, humidity and temperature with the recorded rainfall values. The findings showed that height had a significant correlation with Monsoon rainfall, while humidity and temperature correlated with the monthly rainfalls. Yang and He (2013), using the super innovative firefly algorithm concluded that this algorithm is more suitable than the optimal search strategy. Considering the problems of Urmia Lake located in the northwest of Iran, comprehensive studies with an inclusive approach to the problems in this basin are considered necessary. Indeed, it is necessary to concentrate more on the process used in the design of the rain gauge networks and begin to redesign the existing networks in order to refine and complete them...

Introduction The control of local scour around the piers and bridge abutments has been recognized as an issue of considerable importance due to the structural damage of bridges. Many methods have been already proposed by several researchers to tackle this problem, including methods that change the pattern of flow around the piers, such as sacrificial piles (Melville and Hadfield, 1999; Chabert and Engeldinger, 1956), Submerged vanes (Lauchlan, 1999; Grimaldi et al., 2009a), Slot (Chiew, 1992; Grimaldi et al., 2009b), and collars (Zarrati et al., 2006; Alabi, 2006). In addition to the above methods, other methods have been developed to protect the bed against the scour, including the use of riprap around the pier (Parola, 1993; Graziano et al., 1990), sandy bags, gabions, and geotextiles. The sacrificial piles are, indeed, the piers with smaller diameters than the bridge piers, which divert the flow from the bridge pier leading to the reduction of the scour potential. The efficiency of the sacrificial piles in controlling the scour depends on the number and diameter of the piles, the degree of submergence, the arrangement, their relative placement against the piers, the distance between the piles, the distance between the piles and the piers as well as their angles to the flow (Melville and Hadfield, 1999). According to these methods, many studies have been carried out on the effect of the sacrificial piles in reducing the bridge piers scour. However, the use of submerged piles with different degrees of submergence has been less considered. Since the length of sacrificial piles has an effect on the degree of submergence, the length of the sacrificial piles is effective in scouring, as well. In effect, the present study focuses on the scouring around bridge piers by using 2 different arrangements with and without using the sacrificial pile groups at the upstream of the pier...

Introduction Groundwater is one of the most important water resources on earth, and water salinity studies are very important for the protection and planning of water resources, especially in arid and semiarid areas such as Iran. Groundwater currently accounts for more than 90 percent of Iran’ s total drinking water consumption. This water resource is less susceptible to bacterial pollution and evaporation than surface water, and hence it is more important than surface water...

Introduction Regarding water scarcity and climate change in Iran, it is necessary to choose an appropriate model for water resources management. To study the effects of climate change, the outputs of AOGCMs Models were used (Lane et al., 1999). Downscaled weather data using LARS-WG model were then used in the watershed simulation model to estimate the streamflow and crop water requirement so as to evaluate the effects of climate change. Hydrologic models were, indeed, needed to simulate the streamflow, and input to the watershed simulation model so as to estimate water supply in the watershed. WEAP model can be used for investigating and simulating the water system performance under the influence of climate and management scenarios. (Tarek et al., 2017). The purpose of this study was, thus, to investigate the climate change impacts on the amount of streamflow to water supply into the Sattarkhan reservoir as well as the allocation of water in Aharchay watershed...

Introduction The construction of structures such as spur dikes in open channels and rivers is done to control the coastal erosion or water guidance and diversion. Scouring due to changes in the pattern of flow around the structure may result in instability and structural insufficiency, and if designed improperly, it may lead to complete degradation. Thus, the flow pattern and scour depth around the spur dike should be carefully considered. In effect, the type of spur dike used in each project, depending on its usage in the flow path, the depth of scouring and economic considerations must be carefully selected. The open gabion spur dike is one of the most affordable ones and is of high quality in terms of efficiency and ease of construction...