Journal of Irrigation Sciences and Engineering
Year:2019 | Volume:42 | Issue:1 |Papers Count:17

In this study, a methodology is presented in which hydraulic relationships including mathematical formulas for the variations of the flow area, the wetted perimeter and the flow top width with the depth are computed by inverse solution of the Saint-Venant equations. The main focus is on the comprehensiveness and applicability of the method in practical conditions. Also, one application of the presented method in the case of flood routing is presented. In the context of river hydraulics, inverse modeling usually refers to the estimation of the Manning roughness coefficient via calibration process or identifying boundary conditions by measuring the flow properties inside the domain i. e. water level or flowrate records ( Ding and Wang, 2005, Fread and Smith, 1978, Khatibi et al., 1997, Nguyen and Fenton, 2005). Inverse problems are often inherently ill-posed; and this leads to some difficulties in solving them in comparison with forward problems. Some essential issues must be considered in solving inverse problems including solution existence, solution uniqueness and solution stability (Hansen, 1998). The underlying idea of the present research is to identify the mathematical formulas of geometric-hydraulic relationships for river cross sections. In this case, the unknown parameters are determined in the functional form by inverse solution of the Saint-Venant equations. The proposed model is validated using hypothetical and real test cases; and in each case the actual and identified geometric-hydraulic relationships are compared. Additionally, application of the method is showed for the case of hydraulic flood routing in conditions where no information is available about river cross sections; and water level data records are used instead of river cross sections data...

Rivers have long been considered as one of the most important sources of water supply. Flooding during flood events causes irreparable damage. Therefore, some methods such as the protection of river banks against erosion are considered to control the flood. One of the methods for protecting the rivers and controlling their erosion is the use of groynes. Groyne is a structure that uses rock, sand, etc. to slow down the process of erosion and prevent ice-jamming, which in turn aids navigation. and generates suitable environmental conditions for aquatic organisms in different conditions and in different parts of the river. According to the importance of groynes, a detailed and three-dimensional study of turbulent flow and the intensity of turbulence extension in these structures is of prime importance. In the present research, three-dimensional turbulent flow was completely studied using ADV advanced velocimeter in straight, L-and T-shaped groynes in a straight canal with a rigid substrate and 20% contraction of the groynes in the canal’ s width by collecting numerous data points, and the turbulent extension was studied in three-dimensions, which is one of the novel charactersistics of this research...

With urban developments and the aging of urban water distribution pipes their demand for repair and maintenance is rapidly grown. There are several factors that affect the performance and leakage in water and wastewater distribution networks (Ameyaw and Chan, 2016). By increasing the water leakage from pipes and wastewater depletion from houses to the injection wells, water level under the city ground is rising and saturation condition will be created near the underground infrastructures. In recent years, local uplifting of subsurface water level in metropolises created different challenges over water and wastewater systems with multiple damage effects (Baah et al., 2015; Qiu et al., 2016). İ n recent two decades, the rising of groundwater table in Kerman city have caused several challanges over the water and wasetwaer infrustructures. İ n the ancint zone of the Kerman city, water level come up to 3 meter under the groundsurface and is interacted with several underground structures and basment flooding. The rising water table have several destructive effects over the urban infrastructures. The main purpose of the present study is to investigate the effects of rising subsurface water level in Kerman city by using an AHP based damage prioritization to depict the relative importance or urgency of a damages of water level rising over infrastructures...

Surface water quality is largely influenced by physical processes, chemical and biological processes such as weathering of minerals, rocks, climate and precipitation amount. Human activities (domestic and industrial wastewater, atmospheric sediment, irrigation return flow, etc. ) also can reduce the quality of surface water and disrupt using it for drinking, industrial and agricultural consumption. The investigation of saturation index changes is useful to determine the different stages of the evolution of hydro chemical and chemical reactions to control the water chemistry. The control processes of water chemistry including physical, chemical and biological processes, structural, geological and mineralogical composition of the host rocks, and human activities such as household and industrial wastes, excessive use of chemicals and pollution emissions of wastewater tanks can effectively affect the surface water chemistry. Hierarchical clustering methods are appropriate methods for data analysis of water samples which are applied to assess the water quality data and the possibility of sample hydrochemical grouping having the highest importance of the statistical viewpoint in hydrology, hydrogeology and geology. In this study, Azna river water quality has been investigated based on the major elements and heavy metals. Results showed that the reactions due to area formations are the factor that affects the major elements and heavy metal in the surface waters of area...

Desalination plants dispose with the wastewater feed via channels and pipelines. The behavior of dense flows discharged into receiving water body is very important, thus prompting researchers to conducted numerous studies on the behavior of flows from surface and submerged dischargers. Among the scholars focusing on submerged dischargers, Zeitoun et al. (1972), Cipollina et al. (2005), and Bleninger and Jirka (2008) investigated submerged negatively buoyant jets in horizontal, vertical, and oblique discharge conditions and obtained results on flow trajectory and dilution rate. Furthermore, Researchers have also delved into surface dischargers. Using numerical modeling, Kassem et al. (2003) inquired into the effects of different parameters of an outflow, a bed, and receiving ambient water on the properties of dense flows discharged through inclined and divergent channels. Kotsovinos (2000), Papakonstantis and Christodoulou (2010), Kaye and Hunt (2004) experimentally examined the spreading of dense flows caused by the impingement of submerged jets on a horizontal plane. Papakonstantis and Christodoulou (2010) concentrated on negatively buoyant circular jets and vertical and horizontal positively buoyant jets, reporting that the dense flow in negatively buoyant jets and vertical positively buoyant jets has a circular outer boundary. The authors also observed that radial distance from the impingement point to the outer boundary of flow is related to time by a power of 0. 5. As previously stated, understanding the behavior of dense flows discharged into receiving ambient water is highly important. Correspondingly, this study explored the spreading of dense horizontal flow over the bed of deep and stagnant ambient water...

Saturated hydraulic conductivity is a vital soil propriety in controlling infiltration and runoff, drainage, extracting pesticides, and herbicides from soil profile and transfer them to ground water. The auger-hole method is the most famous and the most common method to measure the hydraulic conductivity (K) that have been used normally for years. Using this method is possible where the water table is high and in a one-meter range from the soil surface. In the measurement of saturated hydraulic conductivity some problems occur when the water table of the soil is very deep. In arid and semi-arid areas especially in summer, the water table is so low making it impossible to use ideal methods. To determine the hydraulic conductivity rates of soils above the water table, different methods are used. These methods have always been faced with weakness in theoretical bases or practical problems as well as being time consuming and costly. One of these methods is the shallow well pump-in test which is the most adaptable method used for this purpose. However, a new method has been developed to measure the hydraulic conductivity above water table which is called the Guelph Permeameter method. As the Guelph method was introduced by Reynolds and Elricks (1985), great changes have been made in this field, and due to the strong theoretical bases, being less time-consuming and cheaper to perform, Guelph method attracted lots of attention. The aim of this research was to calibrate the Guelph Permeameter for the measurement of saturated hydraulic conductivity using the Shallow Well Pump-in Test (SWPT) method at an experimental farm in Shahid Chamran University of Ahvaz. This research examines the calibration of Guelph Permeameter method by using shallow depth pumping test method for a loam soil in this region...

Preventing water penetration and seepage control is of prime importance in hydraulic structures projects. Recent studies show that 30% of dam failures are due to the seepage from dam’ s body or foundation. Seepage control inherently is controlling potential energy of water molecules causing seepage and related losses. Constructing a core with low rate of permeability can considerably control seepage from dam body. So foundation seepages are significantly more than body seepages. Foundation seepage control is done to prevent uplift and piping, two phenomena which led to dam failure. One of the methods for controlling seepage from bottom of earth dams which are mounted on alluvial foundation with high rate of permeability, is utilizing a covering layer with low permeability on bed of river, bottom of reservoir (in upstream) and connecting it to central core of dam. In fact, the role of such methods and mentioned covering layer is lengthening flow path for increasing potential losses and decreasing water energy which is terminated to decrease penetrated water and related losses. This covering layer is called clay blanket. One of the longest upstream impermeable blankets is executed in Tarbela dam in Pakistan with 140 m height. This blanket has 1400 m length and its thickness is 1. 52 m at the dam (WCD, 2000). Khalili and Amiri (2015) investigated cutoff effect in reducing leakage, exit gradient and uplift, both experimentally and numerically analyze by software GEOSTUDIO and referring that the results of the software are in acceptable agreement with the experimental results. Tayfu et al. (2005) used Finite Element Method (FEM) and Artificial Neural Network (ANN) models for flow through Jeziorsko Earth fill Dam in Poland. This case study offers insight into the adequacy of ANN as well as its competitiveness against FEM for seepage prediction through an earth fill dam body. Ahmed and Sattar (2014) used Gene expression models (GEP) for prediction of dam failure and results showed the superiority of the developed GEP models over existing regression-based models...

Destruction of bridges caused by scour and other natural phenomenon brings about financial and life losses. Hence, researchers have been studied extensively the scour mechanism and methods of scour countermeasure. Usually scour at bridge occurs both around piers and abutments. Melville (1992)'s study showed that 70 percent of the failure of bridges in New Zealand was due to the abutment scour. Studies conducted on the failure of 383 bridges in the United States showed that in 25% of them the pier scour, and in 72% of them the damage was due to abutment scour (Kayatrak, 2005). The main cause of the abutment scour is due to complex flow vortices which developed around the abutment. Therefore, during the past decades many measures have been developed to protect the bed material against erosion. These techniques can be categorized in two types of covering methods and flow altering techniques. Design guidelines for some of these mitigation techniques can be found in Melville and Coleman (2000). For existing bridges the common practice is to use armoring materials around bridge abutment. Riprap, gabions, rectangular concrete blocks and tetrahedron frames concrete elements are the most effective material for covering and stabilizing the bed around the bridge abutments. In rivers with high flood discharge, the covering material are subject to high flow velocities and therefore large size of rocks have to be used. When the site construction is far away from mountain area or large sizes of the rocks are not available or too costly to transport, other material should be applied. In the present study, a new concrete element-six – legs concrete (SLC)-beside using of smaller size of rocks have been studied to find out the best combination for protecting bridge abutments against scour...

Water and nitrogen are two main factors of plant production. Water scarcity is one of the most important challenges in the production of agricultural products in arid and semi-arid regions, as in most parts of Iran. A great deal of research has been done on the interaction between water and nitrogen and has shown that irrigation and nitrogen treatments interact with the yield. So far, various models have been developed to simulate plant performance in response to different levels of water and nitrogen. The FAO organization has provided the AquaCrop model. This model simulates yield performance in response to water consumption. The effect of nitrogen deficiency on yield in the latest versions of the AquaCrop model (versions 4 and 5) is carried out using semi-quantitative method. In this method, nitrogen deficiency is assumed to be based on four parameters: 1-Normalized water productivity (WP*), 2-maximum canopy cover (CCx), 3-The Canopy growth coefficient (CGC) and 4-Canopy decline coefficient (CDC). The hypothesis of this research is that there is a relationship between the four above parameters and nitrogen fertilizer for corn, and from them, we can determine the values of four parameters for each fertilizer level and use them in the AquaCrop model. Therefore, the first goal of this study was to determine the equations between nitrogen fertilizer and the four above parameters. The second goal of this study was to evaluate the accuracy of the AquaCrop model for simulating the response of corn to nitrogen fertilizer using parameters derived from the equations defined in the first part...

Hydraulic structures that change the flow pattern around themselves may cause local scouring, since changing the flow characteristics (velocities or turbulence) can lead to changes in sediment transport capacity. The difference in height between the upstream and downstream bed levels of the river-intersecting structures will form a vertical waterfall in the tail-water that plays an important role in grade-control structures. An example of these structures is the Balaroud inverted siphon structure in Dez irrigation and drainage network in the south of Andimeshk county, Khuzestan province, Iran. Various experimental studies on downstream scour of hydraulic structures are available in the literature. The main objectives of this study were to investigate the scour process, estimating the maximum depth and location of the scour hole, and evaluating the maximum height and location of the sedimentary mound at the downstream of the grade-control structure. In this study, the experimental data obtained by the previous researchers was used, and the equations were reviewed and re-written using the D’ Agostino and Ferro (2004) studies in order to improve the accuracy of the existing relationships. In the next step, the hydroinformatic science and the soft computing technique were used to achieve more accuracy for the relationships of the hole’ s characteristic and the sedimentary mound in alluvial ducts containing non-cohesive sediments...

Drought is one of the extreme events that can impact vast areas gradually over time. Also understanding the implications of climate change on drought is important for water resources management in order to manage the available water resources in the basin appropriately. Having better understanding of drought condition, drought indices were developed. Several drought indices are used for identifying and quantifying droughts that among them the standardized precipitation index (SPI) provides proper results. Based on each drought indices, drought characteristics can be calculated namely drought duration and drought severity. Drought characteristics are highly correlated to each other. Trusting on one of the drought characteristics for managing the water resources may lead to inappropriate understanding of drought condition. Therefore, it is important to notice all characteristics together by using a joint distribution function that among them copula function is prevalently used in hydrology studies. Several studies were examined the impact of climate change on the drought conditions by using different drought indices in many basins in the word and Iran (Bazrafshan et al., 2015, Kouchaki ei al. 2007, Mahsafar, 2011, Eghtedarnejad et al., 2016, Naserzadeh and Ahmadi, 2012, Hoffman et al., 2009, Kirono et al., 2011, Selvaraju and. Baas, 2007, Lee et al., 2013, Serinaldi et al., 2009, Mirabbasi et al., 2013). There have been many studies which using copula function in order to compute the return period of the drought (Abbasian et al., 2014, Golian, 2010, Serinaldi et al., 2009, Mirabbasi et al., 2016, Maddadgar and Moradkhani, 2011, Chen et al., 2011)...

While there are several types of salts in the soil, salts that have higher solubility in water are dissolved and removed from the soil, But salts with low solubility in soil, sediment layers hard to cause clogging in the soil or in their coverage. Among the salts in soils of the arid and semi-arid areas, three compounds of calcium carbonate (with solubility of 0. 013 gr/lit), magnesium carbonate (with solubility of 1. 9 gr/lit) and calcium sulfate (with solubility of 2. 5 gr/lit) salts, usually are found in these areas and have low solubility. Among the mentioned compounds, magnesium carbonate accumulation in soil is very low, while calcium carbonate and calcium sulfate salts concentration are found higher and can cause clogging by the sequential deposition. The amount of calcium carbonate in the soils of arid regions may reach up to 80 percent of soil weight. It provides the conditions for rapid deposition and a layer of rigid form and clogging the system (FAO, 1973). This experiment was conducted in order to analyze the application of sugarcane bagasse in controlling the clogging of the agricultural sub-surface drain envelopes...

Recognizing and studying the drought phenomenon with regard to the affecting factors led to better understanding of this phenomenon and paved the way for short-term and long-term planning in relation to encountering, controlling and predicting of this phenomenon. Since to determine the severity, duration, and frequency of drought, is need to determine the drought by using indicators, drought monitoring is essential and researchers have always followed the use of indicators for drought monitoring as a management and planning tool. Drought monitoring is one of the prime factors in drought management. Monitoring systems have important roles in creating the drought plans and its management. Therefore, due to this importance and taking into account the ecological and geographical conditions of Lake Urmia during recent years, the study and monitoring of drought for the above area is necessary. Therefore, the purpose of this study was to investigate the drought characteristics and calculate the three (SPI, PNI, CZI) drought indexes and comparing their efficiency and accuracy in the Western Azerbaijan province, as well as evaluating the time trends of their changes over the entire province...

Spillway gates are used to increase water depths on power generating turbines, regulate the flow passing the spillway and augment the safety of the dam and its installations during flooding. Inappropriate performance, inaccuracy in determining the proper dimensions and sudden opening of the spillway gate(s) causes vibration, overtopping, instability in the dam, and also damages to the dam's body, its installations and even downstream areas. Regarding the rainfall reduction, adjusting reservoir level, increasing water pressure on power generating turbines and proper use of water inside the reservoir, determining the accurate dimensions of the gate and making smart spillway gate(s) are required. Using the technique of linearizing the equations of discharge passing spillway and water level inside the reservoir and the point of equilibrium of the incoming and outgoing discharge hydrograph, the dimensions of the spillway gate are carefully designed and constructed in accordance with the environmental conditions and its installation site. By smarting the spillway gate and determining its precise dimensions, it will be possible to control floods remotely, manage water consumption, save manpower and reduce visual error...

There are various models for flood prediction that are based on different conceptual basis. The current SCS-CN model is a well-known model in this field that is widely used in Iran and other countries. Recent researches focuses on improvement of this model and improve its efficiency but it is necessary to evaluate the improved models for catchments of Iran. The objective of this study is the comparison of current SCS-CN and developed Mishra-Singh (One Parameter) models for flood hydrograph and peak estimation using data of five catchments in Golestan province...