فصلنامه علوم و مهندسی آبیاری
سال چهلم شماره 4 (زمستان 1396)

For the simulation of soil water flux, the relationships between the soil hydraulic conductivity, water content and pressure head are required. The relationship between soil water content ( with soil pressure head [h( ] and hydraulic conductivity [K( )] are usually obtained by fitting experimental equations. Describing these relationships, the experimental equations such as van Genuchten (van Genuchten, 1980) have been used. Zand-Parsa and Sepaskhah, (2004) proposed a new method for prediction of the soil hydraulic conductivity function [K( ) based on specific liquid-vapor interfacial area around the soil particles and Zand-Parsa (2006) improved this method for a more straightforward and efficient numerical technique for prediction of function.
The different equations of h ( and K ( ) have three to five soil hydraulic parameters, which vary considerably in different soil groups. For measurements of the soil hydraulic parameters, laboratory and field methods are time consuming and require excessive financial costs; hence, inverse methods have been used by many researchers. Estimation of the soil hydraulic parameters with using the inverse method is usually less costly and time-consuming than the direct methods, especially for in situ characterization of large sites. Soil hydraulic parameters can be predicted using the inverse method, which are the combination of the numerical model with an iteration algorithm, and genetic algorithm for parameter estimation values (Kamali and Zand-Parsa (2016); Mahbod and Zand-Parsa (2010). For a given initial and boundary conditions and soil hydrauic parameters, Richards’ equation can be solved with numerical methods.
In this study, soil hydraulic parameters were estimated by inverse method based on the soil-water characteristic curve of van Genuchten (1980) method, the function of soil hydraulic conductivity- water content obtained by the method of liquid- vapor interfacial area around the soil particles (Zand-Parsa, 2006).

Soil moisture measurement is very important for better irrigation system management. One of the indirect methods for measuring the soil moisture content is to use Theta Probe device. Although the use of Theta Probe has many advantages over the other methods of measuring moisture content, but according to research conducted in most regions of the world, it has been shown that changes in the physical and chemical properties of the soil, and in general, all that affect the dielectric constant of the soil, cause an error in the accuracy of the measurement of moisture content with this device. Among the physical and chemical properties of the soil, the tissue type, the amount of clay contained in the soil, and electrical conductivity (EC) are the three main factors influencing the calibration of the Theta Probe system (Sarani and Afrasiab, 2012). The aim of this study was to investigate the effect of soil texture, irrigation water salinity (EC), and sodium absorption ratio (SAR) on the accuracy of Theta Probe device.

Improper usage of unqualified water in agriculture has triggered salinity in many areas. The area of saline lands as a result of aquatic agriculture has increased 44.5 million hectares until 2005 in Iran (Banai et al., 2005). As a result of Soil salinity over the plant tolerance threshold, excessive accumulation of salt in the root zone can be a serious threat to plant growth (Silsepour and Rashidi, 2008). Reducing plant growth indices such as leaf and vegetation decreases evapotranspiration (Shani and Bengal,2005). Subsequently, the decline in plant growth will reduce crop production in many plants (Kaman et al,2008). Sorghum due to physiological characteristics such as drought tolerance, salinity, water use efficiency higher than other forage plants, relatively high yield, desirable quality, and its ability to maintain as dry forage, especially silage has a special value in arid and semi-arid regions (Zarbin and Thomas,2003). Tabatabaei and Anagli (2012) examined the effect of salinity on sorghum in the germination stage. Their study results showed, Sorghum of KFS2 cultivar is introduced as salinity tolerant sorghum due to the highest amount of germination in saline conditions. Sistan is one of the important areas for the development of sorghum in the country and in terms of cultivating corn and forage Sorghum has the fifteenth place among the provinces of the country(Binam,1388). The lack of water in Sistan plain is a serious issue. The only water source in the area is the Hirmand River, which originates from the Baba mountains of Afghanistan. The region's water crisis is due to water shortages in this river. so that, the lack of hydrometeorological water has led to the destruction of the region's agriculture. Therefore, planning for the best use of water resources is essential and inevitable. By choosing proper method for managing salty water, product performance reduction can be prevented as much as possible and reduce non-salt water demand, and by the obtained results it is possible to plan properly to increase the agricultural production in special circumstances (salinity restriction). Therefore, this study was conducted to investigate the effect of saline water management methods on yield and yield components of sorghum.

Providing safe conditions for water pipelines or other fluids on erodible beds is an important issue in the field of hydraulic engineering. Studies show that the installation of a plate called Spoiler on top of the pipeline increases the amount of the erosion around the pipe and its self burial stimulation. Most studies about spoiler have been done on a fixed pipe, but in reality, when the scouring hole underneath the pipe is deep enough, the pipe begins to lower as a result of the weight, at when the pipe reaches the bottom of the scour hole, the erosion process stops and then the pipe is covered with sand and buried. The self burial phenomenon has not been studied with the use of a spoiler in the case of actual displacement of the pipe, and due to the fact that the studied pipes have been fixed, the transitional and sedimentary phases have not been observed. Considering the role of pipe displacement in changing the scouring profile, the study of the spatial phenomenon of the pipe during displacement and observing the actual effect of the spoiler on the self burial performance and its effective parameters are necessary. In this study, this phenomenon has been studied experimentally.

The idea of using canoe-fishway was first proposed by Hassinger (2002) and was experimentally conducted in the hydraulic laboratory of the Kassel University. Hassinger and Kraetz (2004) presented the general principles of the canoe-fishway design.
The idea of this new development was driven by the thought that a great number of thin and elastic rough elements on the one hand show a good performance in energy dissipation, and on the other hand, allows a man-driven boat to pass without being damaged. The brushes should be both firm enough to provide energy loss necessary to help fish climb easily and flexible enough to allow boats to pass through without being damaged and after the boats passing, the brushes will come back to their original state. About half of the experiments in running these facilities focuses on their application as only a fishway and the other concentrate on a hybrid structures as a canoe-fishway. Figure 1, shows an example of such fishway type (Hassinger., 2009).
In recent years, the development of studies and the construction of rubber dams within walking distance to the sea on the rivers in the north of the country, necessitate the need for constructing the environmentally friendly fishway. Constructing rubber dams near the sea disrupted the fishermen commuting and thus has created social tensions (Hedayati et al., 2012).
Hedayati et.al (2012) designed a canoe-fishway on Tajan rubber dam in Mazandaran province and compared it with the classic vertical slot fishway.
In this study, given the importance of creating environmentally friendly fishway on rubber dams in Mazandaran province and the problems created for small fishing boats travelling on Tajan River, first the laboratory canoe-fishway model was prepared by taking into account the fish biological parameters in Tajan, Then the depth and flow velocity were evaluated.

One of the important factors which has led to reduction of the sugarcane yield is short-term water stress either in growing season or in the meantime of two sequence irrigation events. Therefore, studying and monitoring of crucial parameters of sugarcane water content (canopy temperature, soil moisture and vegetation moisture) is essential. The main objectives of present study are monitoring the effective parameters of sugarcane water content, and consequently determining the correlation between two different methods for determining irrigation schedule which are based on the canopy temperature and the leaf sheath moisture measurement, in order to have an efficient irrigation scheduling as well as determining the time and the amount of irrigation, accurately.

Selecting a model that simulate the runoff with high accuracy and less error, can be helpful in favorable management of water resources plans and increasing the performance of these plans. Also, increasing the accuracy of runoff simulation in the basins with no meteorological data, is of great significance in efficient management of water resources in these basins.

The most common way to dissipate the water kinetic energy at the downstream of weirs , gates at chutes is to use the hydraulic jump. Hydraulic jump is a phenomenon that alters the flow regime of the state of supercritical to the subcritical with dissipating much of the flow kinetic energy and to prevent possible downstream scour of the structure. Development of the downstream scour hole of the hydraulic jump stilling basins can cause failure of the structure itself , which has been the interest of the researchers in the past. The extension of new roughened bed basin is essential to pursue and complete what previous researchers concluded for these basins.Safe and an economical design of hydraulic structures, an estimation of the maximum scour depth, and to minimization the scour dimensions is the interest of the researchers. Therefore, in this study the effect of placing the six-legged concrete elements under different lengths was investigated investigated. Covering the river bed downstream of the spillways and gates with these roughened and permeable elements can decrease the stilling basin length and expected less scour depth. These elements are tight together and placed on the bed. The covered length of the bed is equal to the length of jump on these elements. However, there is possibility in which few rows of the downstream elements are escaped because of the edge failure and therefore the roughened bed length is shortened. The main purpose of this study was to see how much exactly would be the magnitude of downstream scour depth if the covered length is decreased. .

Distribution pattern of the river bed particles grading creates important issues in investigation of the hydraulic, geomorphological and ecological behavior of the river.. For example, surface grain-size variability is crucial for illustrating sediment transport (Hoey and Ferguson, 1994; Russ, 1999; Joyce et al., 2001).
Particle size characteristics that are dependent on particle size distribution are estimated in different ways, such as sieving method, sampling techniques in the field, photographic print method, and the other methods that have been suggested so far (Aberle and Nikora, 2006). The most prevalent method is the sieving method that obtains particle size distribution curve using cumulative weight of passing aggregation,.. It is obvious that, measurement of the particle size distribution based on field methods are time consuming, overwhelming and non-economic, so developing a fast and accurate method for measuring the particle size distribution of the river bed has a significant effect on civil and environmental engineering. Nowadays, this process is possible using image processing methods to automatically extract particle size using digital images of river bed. Various methods have been reported which aim to provide robust and automated estimates of grain size from images, falling under two broad categories classified by (Buscombe et al., 2010) as, respectively, ‘geometrical’ and ‘statistical’. Both techniques require imagery where the smallest grains are resolved by at least a few pixels. Statistical methods characterize grain size using a measure sensitive to image texture. These approaches have used autocorrelation (Warrick et al., 2009), semi variance or one of the several other methods, including fractals (Buscombe, 2013) and grey-level co-occurrence matrices. Geometrical methods use image processing techniques (principally, threshold and segmentation) to isolate and measure the visible axes (or portions of whole axes) of each individual grain (e.g. Graham et al., 2005; Chang &Chung, 2012). This research showed that new methods of image processing have an adequate potential to replace with previous traditional methods. Also, the percentage of human bias in methods such as field sampling or Sticky layer is very high for sampling of the Armor layer of the river bed, while the image processing method has enough power to take all the details and analysis of the data and it has a desirable accuracy compared to traditional methods.
This research, with using image processing toolbox in MATLAB software, tried to improve the detection filters and finally determined the size distribution of sedimentary particles of armor layer in the alluvial river bed.

Spur dikes are one of the coastal protection methods. Bandal- like is a local type of spur dikes that would be constructed to improve the water depth for navigation in alluvial rivers. This is a new type of spur dike that is a combination of permeable and impermeable spur dike. The goal of this study was to investigation the effect of Bandal-like spur dike submergence on bed topography. For this purpose, Bandal-like was tested with 3 submergence ratios of (1/16,1/65,2/15) and different hydraulic conditions (0.22,0.235,0.26 and 0.29 Froud number) in mild 90 degree bend. The result show that by increasing of the submergence ratio, scouring around Bandal-like increase too. Also, the results showed that by increasing of the Froude number and densiometric Froude number, the maximum scour depth increases too The investigation of the maximum scour showed that the location of scouring does not match the shear stress pattern in mild bends.

Due to the impact of various factors, selecting the best irrigation method for different conditions of the field has become a complex issue (Montazar and Behbahani, 2007). In this study, the best irrigation system selection among the sprinkler systems (including solid set, hand move, wheel move, traveling gun, center pivot, and linear move), trickle systems (including row crop drip, drip, and bubbler) and surface irrigation systems (including basin, border strip and furrow) was done using Charles Burt scoring method (Burt et al., 1999) for Famenin, Qahavand and Razan plains of Hamadan province. Scoring of the systems were performed based on some related properties such as the type of production, type of water source, climate, land, soil, social structure and, conditions of the studied regions. According to the results, the best choices and suitable irrigation methods among the mentioned systems based on their priority in the studied area were; solid set, drip tape and basin methods in sprinkle, trickle and surface irrigation systems respectively. Despite increasing the labor costs due to sprinkler’s displacement, the solid set method with moveable sprinklers due to less investment was selected as an appropriate and advisable system. If surface irrigation system is identified as the suitable choice for an area, the use of low pressure distribution networks and gated pipe systems can improve the irrigation efficiency and reduce the infiltration losses, which should be considered in projects.

Beach-bound plates are used to control the erosion of the walls of rivers and beaches. The nose of the plates has always been subject to scour due to the flow contact with the structure. Different factors are effective in reducing the scour. Recent research has shown that coastal and beach-bound triangular slotted panels have played an important role in reducing the scour around the nose. In this study, in order to investigate the effect of the angle, the triangular slab (slit area = 10% of the effective surface area of ​​the plate) was used at different angles of (23, 30, 40 and 60 degrees) in arched flume. Experiments were conducted under different hydraulic conditions (landing numbers 287/0, 304/0 and 322/0). The results showed that the maximum scour depth at the 23 and 40-degree angles was the lowest and the highest, respectively. The maximum stacking height is proportional to the maximum scour depth. By increasing of the angle of the plates up to 40 degrees, the maximum scour depth is farther away from the outer curve and drops sharply at an angle of 60 degrees.
One of the issues in river engineering is erosion in the walls of rivers and coasts, due to the direct connection of the flow with the wall. The pattern of velocity distribution in the arc indicates the concentration of areas with maximum velocity in the lower arch and in the vicinity of the outer wall. Spoons are considered as protective structures that are used to reduce the erosion and improve the stabilization of the riverside wall. But, on the other hand, the location of the spillway in the flow path and the direct impact of the flow on the structure leads to local scouring around the nose of the spillway and, as a result, will eventually destroy the structure. It is noteworthy that the coastal triangular board of the modified state of the protective structures (in terms of appearance, degree of submergence, There is a gap in the page) for A. Judd minimum depth of scour around the nose page. . In a study by Boyan et al. (2010), in a single-seater survey of coastal triangles, the effective method for restoring river banks is to install these panels at low angles (20 and 30 degrees) and in the coastline. Therefore, due to the limited research done on the beach-bound plates, in a leading research with the installation of single-skeletal triangles attached to the coast at different angles, the angles of their placement on the topography of the bed in the 90-degree arc have been studied.

Developing of techniques for regional flood frequency estimation in ungauged sites is one of the foremost goals of contemporary hydrology. The flood frequency evaluation for ungauged catchments is usually approached by deriving suitable statistical relationships (models) between flood statistics and basins characteristics. Already, several equations have been presented to estimate the flood frequency in different areas such as Karkheh basin. However, due to the complexity of this phenomenon, the relationships have not been capable to simulate the flood frequency with desired accuracy. Accordingly, in this study, in addition to the regression method has been used in the previous studies, the ANN and ANFIS models are applied. In fact, these are a type of black box models without any knowledge of processes within the system, in which inputs are converted into outputs (or output). This situation indicates that this type of new models is actually similar to the regression relations, however, there is further flexibility in adjusting the weights and thus can be used as a replacement to multivariate regressions.

Usually protective structures are often used in coastal area and river or sea sides. In most cases, these structures are retaining walls which used to prevent the river sides erosion . Due to the contact of structures with the local soil , the study of soil interaction with structures and lateral pressure of soil is very important. Hence, the effect of particle size and compaction of backfill behind the wall is studied as an elastic analysis of wedge of body motion cantilever retaining wall in this article.

Development of irrigation and drainage networks is known as one of the most effective approaches for the optimal use of limited water resources (Abbasi., 2011). But many of the constructed networks suffer from different problems which raised from different reasons. Rahimi et al. (2011) categorized these reasons as; poor design, improper construction operation, low quality of construction materials, poor operation and maintenance, and geotechnical problems of the subgrade materials. Stilling basins are commonly used structures in order to dissipate the energy in downstream of chutes. In general, a hydraulic jump would be created at the end of the chute. The B-type hydraulic jump takes place on the positively inclined plane of a chute under particular conditions. In this condition, determination of the secondary depth and the length of the roller is essential for protecting the structures. Since there is no proper analytical method to solve the momentum equation for the mentioned condition, using of different smart techniques such as artificial intelligence was considered recently. Caralo et al. (2011) developed different models for determination of the flow characteristics for B-type hydraulic jump. Dusan etal. 2012 presented a neo- Fuzzy system for predicting the weir coefficient. Akib etal. (2014) predicted the scouring depth by using of neo- Fuzzy system. Azamathulla et al. (2012) developed a neo-fuzzy system for prediction of the sediment transport. In this research, the application of two intelligence methods including Neuro - Fuzzy Inference System and fuzzy inference system were investigated.