مجله مهندسی آبیاری و آب ایران
پیاپی 36 (تابستان 1398)

In this study, the potential of Support Vector Machine (SVM (in the prediction of peak outflow due to dam failure was evaluated. Huge volume deposited behind dam may cause a large casualty in case of sudden release of it to downstream. Head and volume of water at the time of failure were considered as inputs to SVM model. To train these models, 70% of 112 gathered data from literature was used as training subset and the rest 30% was used to test the model as test subset, at the same time these two subsets were selected in a way to be statistically similar. After studying four SVM models with different kernel functions, i.e. Linear, Polynomial, Radial Basis Function and Sigmoid, it was found that SVM with Radial Basis Kernel function outperforms other models. Results of the statistical evaluation of the proposed model are satisfying with R2=0.96, RMSE=0.03 for training phase and R2=0.94, RMSE=0.05 for the test phase. A comparison was made between some conventional empirical equations and the proposed model in which results shows proposed SVM model surpasses empirical equations in predicting peak outflow due to embankment dam failure.

The use of appropriate emitters, such as perforated-pipe in the subsurface irrigation system, improves the efficiency of these systems. In present study, the best hydrodynamic conditions of the permeation environment, optimal hydraulic conditions of the orifice, and interaction between the orifice hydraulic and the surrounding environment are investigated. For this purpose, the conditions of flow and outflow resistance of the 16 mm polyethylene pipe with 1, 2.5, 5, 8 and 10 mm orifice were conducted in two modes (with and without geotextile cover) in a clay soil and 12 mm gravel in the pressure 0.25, 0.5, 0.75, 1, 1.25, 1.5, 1.75 and 2 atmospheres are investigated. The experimental results were compared with two-way ANOVA and the characteristic curves of different orifices were fitted with pressures in all experiments.
The range of the values of R2 and the power of the discharge-pressure equation was Obtained 99% -93% and 0.41-0.63, respectively. The experimental results showed, using gravel around the buried orifice in the soil in all the diameters reduced the flow resistance, increased water outflow of the orifices and increased flow turbulence, conversely, using the geotextile increased the flow resistance and it was observed that in the 1 and 2.5 mm orifices, geotextile envelopment in soil and gravel have significant difference with the normal state. Based on the results of the use of 1 mm orifice in all environments and 2.5 mm orifice in the soil environment with or without the geotextile cover, had the best performance and other orifices are not recommended

Rivers discharge prediction in condition of situation appearance of compound channel is one of the important parameters in the flood and rivers engineering.in this investigation compound channel discharge has been predicted by using data drivens such as artificial neural network and support vector machines (calissification, regression) and also empricial method of channel divided by vertical division.For this purpose collected 150 expremental data frome 6 scientific source. this data divided to four categories twenty five percent by using k fold cross validation.in each modeling in data driven approaches, model testing performed by one group of data.After averageing of the same results in each data driven approach, the results showed the superiority of the SVR method .this method  has maximom of  , NS(equal to respectively 0.92875,0.898075) and has minimum of RMSE,MAPE (equal to respectively 0.08435( ),23.89%) and also has percentage maximom of relative superiority of RMSE than artificial neural network was performed more successful than other methode in the compund channel discharge prediction.

In this research, the efficiency of Neuro-Fuzzy System was evaluated for estimating runoff in the mountainous area of the Haraz watershed. The goal is to create a model with proper functions and membership degrees that can properly estimate the relationship between rainfall and runoff in either basin or watershed. Thus, to predict the amount of runoff, 44 different combinations of rainfall, temperature, evaporation, flow rate and antecedent precipitation index with lag time entered to an ANFIS model during the period of 32 years as a daily data. Among the different combinations of input, the structure of rainfall and mean temperature of current day with moisture index and flow rate of 1-day ago was selected as the appropriate model. The results of t-test for determining the significant difference showed that there is no significant difference between ANFIS and MLR methods. The ANFIS system with a two degree triangular membership function with RMSE=2.67, VE=4.16, R2=0.98 and EF=0.97 compared to the MLR with RMSE=2.83, VE=4.55, R2=0.94 and EF=0.92 during the test period, has a better performance in rainfall-runoff modeling of the mountainous area of the Haraz watershed.

Sedimentation by gravity is a common, highly applicable separation method for the suspended solid particles of water and wastewater. Sedimentation basin is an important component of every water treatment process. Due to high maintenance costs of these basins, up to about 30% of all costs in a water treatment plant, optimum performance of settling basin is very significant. In order to improve the efficiency of the basin, engineers have proposed various methods, among which, “changing the geometry along with installation of baffle in the basin” is economic and has attracted the attention of researchers. In the present paper, numerical simulation was made by using Flow3D software and RNG k-ε turbulence model for a flow consisting of settlement particles in the rectangular settlement basin by a finite volume method (FVM). This study aims at numerical simulation of the hydraulic flow in settling basins with various baffle configurations, and finally, obtaining the best geometry for the baffle. Considering the relative consistency of the numerical model results and the experimental data, the numerical simulation results were validated using the Flow3D model. The results showed that the flow in the settling basin is severely affected by the baffle. According to the studied models, it is clear that the baffles installed with lower height and closer to the basin inlet and baffles with high height and far away from the basin inlet have the most effective case on the settlement efficiency.

Friction factor as an index for flow resistance depends on grain size and bed forms in coarse-bed rivers. A wide range of particle sizes located in these rivers causes development of the armor layer and cluster structures, which have great effects on friction factor. In this study, coupling effects between the armoring process and the friction factor due to an armor layer have been investigated. Therefore, considering logarithmic velocity distribution characteristics, the total friction factor was determined. Then, grain friction factor was determined by the Keulegan and the Shields parameter methods and results were compared. Finally, form friction factor was determined by subtracting the grain friction factor from the total one. Analysis of results showed that the friction factor is rather independent of grain-size distribution of the material forming the bed and the major controlling parameter is the slope of the energy grade line. These unexpected results are due to the coupling of the friction factor with the incipient motion problem and the rearrangement of the grains of the coarsest fraction in the armor layer. Also, the results showed that making and development of the armor layer accompanied with clusters of particles caused an increase in the relative roughness of the bed and a reduction in the relative submergence resulting an augmentation in flow resistance and bed stability. Field observations demonstrated that rivers could change the critical Shields stress due to making equal mobility of coarse and fine sediments.

The precise estimation of reference crop evapotranspiration (ETo) has a significant role in improving water management in field and irrigation management. Different methods are available for ETo estimating. The FAO-PM equation is the most reliable method for ETo estimating, but this method requires large input data that is not fully measured in most meteorological stations. Also, the measured data lacks enough precision, especially in developing countries. Therefore, the researchers have used the empirical equations with minimum input data. In this study, the daily values of ETowere calculated at the synoptic station of Mashhad using Priestley-Taylor, Hargreaves, the FAO-PM proposed method by the lack of data and two forms of the Valiantzas equation. Then, the calculated values were compared with FAO Penman Monteith (PM) method. In this paper, new models for estimating ETo were presented by lack of wind speed and relative humidity data by modifying two forms of the Valiantzas equations. The results showed that by the lack of wind speed and relative humidity data, the modified Valiantzas model had the highest accuracy compared with the other methods. It was showed that the R2, RMSE and MAE indices were 0.85, 1 and 1.26 mm per day, respectively. Also, the results showed that the modified Hargreaves method had the highest accuracy when only temperature data is available.

This study was carried out to study and analyze the effect of time-scale changes on chaotic range of discharge of upstream and downstream stations of Zayandehrud Dam Reservoir, trend of changes in the correlation coefficient of flow and forecast horizon for 43 years (1971-2013). Also, the relationship between correlation dimension and forecast horizon is determined over time. For this purpose, discharge of hydrometric stations of Eskandari, Ghale Shahrokh, Pole Zamankhan and Pole Kaleh have been used in four daily, 3, 5, and 7-day time scales. As a first step, the time delay and embedding dimension of the system are calculated using the method of average mutual information and the nearest false neighbors. Then, fractal dimension of the system is estimated using the correlation dimension method. Then, using the Lyapunov's exponent, the prediction horizon is estimated in the chaotic series. Results revealed that flow rate at a 5-day scale has a random behavior at Pole Zamankhan station and at a 7-day scale at the Pole Zamankhan and Eskandari stations and is chaotic in other time scales. Eskandari, Ghale Shahrokh and Pole Zamankhan stations have low chaos at all chaotic scales. At Pole Kaleh station, the flow rate is low in chaos at daily scale and has average chaotic domain at 3, 5 and 7-day scales. According to the other results, by increasing the time scale, the correlation dimension increases and the forecast horizon decreases. On the other hand, according to the Lyapunov exponent, the upstream stations of Zayandehrud Dam Reservoir have more prediction horizon than downstream stations in all time scales.

One of the main challenges hindering optimal water resources management is the problem of optimal exploitation of dam reservoirs. Different methods have been used for optimization problems, but since conventional optimization methods are unable to solve complicated optimization problems, the metaheuristic algorithms are increasingly focused on. As such, the present study uses a genetic metaheuristic algorithm for optimizing Chah-Nimeh water wells of the Sistan region. The main objective is to optimally allocate the water of Chah-Nimeh reserves to users in the Sistan region using a genetic algorithm in the context of managerial scenarios with an emphasis on the scenario of dust stabilization. The results of the genetic algorithm show that in the first year, the optimal discharge rate is 20.3531 million m3 and the demand is 98.3121 million m3, so 77.959 million m3 of the demand is unsatisfied. The results reveal that the genetic algorithm could give a proper optimal answer. Furthermore, it is found that in dust stabilization scenario, shortly after the implementation of the scenario, the discharge will not be possible for the agricultural sector anymore (by 2010).

Evaluation of a system needs a combination of indicators that can show their current situation and future. Multilayer aquifers are more complicated due to different recharge and discharge processes of each layer. This paper aims to evaluate sustainability of phreatic and confined layers of an alluvial aquifer in Golestan province. The relevant data includes monthly precipitation of 19 rain gauges, groundwater level of the phreatic layer in 19 observational wells and piezometric level of 19 wells in the confined layer. In this paper combination of eleven indices that selected according to available data in the region, is used to assess sustainability. Results show in spite of detecting no significant trend in the precipitation data, there is descending trend in the water table of phreatic layer and piezometric level of confined one. Aquifer sustainability index of phreatic and confined layers are 0.89 and 1.01, respectively, that means unsustainability of both layers and worse condition of confined layer. Of course unsustainability of the confined layer has been covered by existed non-renewable groundwater resources. According to groundwater abstraction development index equal to 0.26, implementation of water resources development plans is allowed with considering limitations in terms of water quantity and quality. Also 2.82 as the aquifer recovery potential index revealed if driver factors change toward providing sustainable conditions, both layers can be recovered soon. It can be concluded that the region is facing water scarcity that is a limitation to economic development and human health and well-being.

Water is as the primary input in the production function of agriculture, industry, and mining, as an intermediate commodity in tourism, services, and commerce, as a commodity in the consumer basket of households and as the most important factor in the environmental sector. it is also perhaps the most important commodity- Social and environmental factors. Considering the increasing demand and the decrease in water supply, which leads to the scarcity of water, especially groundwater, the impact of this variable on economic growth and its reciprocal relationship is highly regarded by economists. The purpose of this study was to evaluate the kernel causality between extraction of groundwater resources and economic growth using the Nadaraya-Watson regression model and the generalized correlation coefficient for Iran's economy from 1982 to 2015. The results of the research show that although Granger's causality indicates that there is no relation between water consumption and GDP, the generalized correlation coefficient and nonparametric regression show the existence of unidirectional kernel causality from consumption of water to GDP. Therefore, the drop in groundwater levels and the depletion of groundwater aquifers can greatly affect economic growth.

Several indicators have been proposed by researchers for the study of drought, each of which having certain strengths and drawbacks depending on the regional conditions and parameters affecting drought. In recent years, RDI has received greater attention as it accounts for precipitation and evapotranspiration, and is sometimes used as the basis for comparison of drought severity and the assessment of its potential damage at the national level. The present research examines RDI index along with benefits, drawbacks and problems of zoning and generalization of findings at the national level to provinces. For this purpose, the statistics derived from synoptic stations of Yazd province was utilized and after calculating RDI for each station, a comparison was drawn with the results presented in the national RDI map for the same time period. The results of this study provide technical points and considerations for calculating and zoning RDI at the national scale and generalizing findings to provincial levels, with special emphasis on Yazd province. It also offers relevant executive suggestions for improving the precision of drought zonation studies and methods across the country, which have been discussed in details

Pollution of drinking water is one of the fields of important concern to environmentalists. Water quality is an indicator of health and welfare of a community. In this research, the concentration and mapping of some quality parameters of drinking water in Malayer city were evaluated using statistical and GIS techniques The study populations were drinking water distribution networks of Malayer. For this purpose, the city divided into several areas so that covered the total urban area. A total of 50 drinking water samples were taken from the drinking water distribution network, during May 2016. The various parameters such as, pH, Electrical conductivity (EC), cations (Na, K), and anions (NO3) were measured. The concentration of nitrate was measured by spectrophotometry and sodium and potassium by flame photometer. The mean values of measured parameters were nitrate 27.61 mg/l, pH 6.79, electrical conductivity 0.69 dS/m, potassium 0.41 mg/l, and sodium 1.37 mg/l.The range ofnitrate levels from obtained samples varied between 19.34 and 47.83 mg/l. All measured parameters for drinking water samples from Malayer were observed to be lower than the WHO standard and the national standard of Iran. With regard to GIS maps, the concentrations of NO3, Na and EC were higher in northern and northwest regions. One the reasons for the high concentration are unsafe disposal of municipal wastewater. In order to prevent the increase of nitrate in the drinking water distribution network, doing of some actions such as no discharge of municipal wastewater to water sources and wastewater treatment seems to be necessary. With attention to the classification of polluted waters with nitrate 20-45 mg/l, drinking water of Malayer city were regarded polluted.

Traditional Surface irrigation is one of the common irrigation methods due to its simplicity. In this method, by removing the part of the transfer channel wall, water enter to the furrows but sometimes a simple structure called siphon also is used. This research has been done to evaluate two traditional and structural(siphon) surface irrigation methods in Moghan agricultural research station in 1396. For this purpose, two plots of farm were selected and in the first part traditional surface irrigation method was used and in the second part, the siphon structure was used for corn cultivation. The results of the research showed that in ten times irrigation, amount of water consumed in the structural method is 1251 cubic meters less than the traditional method. Also, the mean water velocity during furrows in structural irrigation method is 0.18 (m/min) more than traditional method. Water use efficiency and irrigation efficiency were respectively 1.01 and 61% in traditional irrigation method and 1.2 and 71% in structural irrigation method also crop yield in two methods was approximately the same. In general we can say that despite the crop yield equality, structural irrigation method is better than traditional method due to water saving and increasing irrigation efficiency.

In order to setting the time of irrigation of the sesame plant using a evaporation pan, an experiment was conducted for two years and three replications in the major cultivations of country (Bushehr, Darab and Jiroft) Irrigation treatments were I0 (irrigation based on conventional harvest), I1 (Irrigation interval based on 90 mm cumulative evaporation from class A evaporation pan), I2 (Irrigation interval based on 120 mm cumulative evaporation from class A evaporation pan class A evaporation pan), I3 (Irrigation interval based on 150 mm cumulative evaporation from class A evaporation pan), I4 (Irrigation interval based on 180 mm cumulative evaporation from class A evaporation pan), I5 (Irrigation interval based on 90 mm cumulative evaporation from class A evaporation pan until beginning of flowering and 180 mm cumulative evaporation from class A evaporation pan after flowering) And I6 (Irrigation intervals based on 180 mm cumulative evaporation from class A evaporation pan until beginning of flowering and 90 mm cumulative evaporation from class A evaporation pan class A evaporation pan class A evaporation pan after flowering).The results showed that Sesame did not have much susceptibility to water stress before flowering.at all points of the project and can be set the Irrigation intervals based on 180 mm cumulative evaporation from class A evaporation pan (about 12 days) But this irrigation program at the beginning of the flowering Reduces performance significantly And Irrigation should be ased on 90 mm cumulative evaporation from class A evaporation pan (approximately 7 days)