1. Introduction; Researchers have suggested different equations for river bank profile, such as trigonometric, parabolic, exponential equations, etc [1]. In this research, a laboratory study has been conducted in a straight reach of sand-bed river in order to validate ten types of river bank profile equations. For this purpose, several stable channel geometry and especially experimental observations for channel bank shapes were compared with theoretical bank profiles and then the mean standard error of each equation was calculated and according to the results the closer ones were identified.

Background and Objectives: The bed forms or in the other word, bed irregularities are structures that form due to stream flow and they have direct impact on roughness and flow resistance in sand bed rivers. Bed forms have different shapes and forms in sand bed rivers. Since river discharge and flow velocity are totally affected by roughness, accurate prediction of the shape of the bed is of great importance. Due to the influence of different parameters in the formation of the river bed form, it is difficult to determine the governing equations and the mathematical models with sufficient precise. Today, the use of artificial intelligence systems has expanded as a new way of analyzing water resources issues. The objective of this research is to introduce a method that can be used to predict the shape of the river bed with high precision. Materials and Methods: In the present study, in order to obtain better results and to reduce the dispersion of data, the data were randomly divided into two parts of the training (70%) including 1647 laboratory data and test (30%) containing 560 laboratory data. The decision trees were coded on the data of the test section in the WEKA programming environment and finally calibration was performed on the data by using Random Forest and Random Tree algorithms. Then, the experimental methods of Van Rijn, Engelund and Hansen and Simons and Richardson were implemented on test data. Results: Evaluation of the results were done using root mean square error (RMSE), Correctly Classified Instances and Roc area under curve. The results showed that the best performance reached by Random Forest algorithm for experimental data with statistical criteria of CCI=85 (%), RMSE=0. 17, ROC=0. 97. On the other hand, by examining the results of empirical methods, it was determined that for laboratory data, van Rijn method has better performance with the results of CCI=64 (%), RMSE=1. 07. Among different environmental variables of discharge, width, depth, slope of the channel, average diameter of sediment particles and temperature for laboratory data were the most important parameters in predicting bed forms. Conclusion: In this research, the superiority of soft computing models was evident compared to the empirical methods in modeling and prediction of the bed form and the models performed in the VKA environment were better. Basically, because of the formation of the river bed form is depended on several factors and also because of its complex nature, the prediction of this phenomenon is very difficult and sometimes with high errors. Since artificial intelligence methods are used to analyze issues that do not explicitly describe the nature of the problem, so many of the issues of bed form can be solved with these methods.

1-Introduction: Fluvial and aeolian processes are important factors in changing the surface of morphology in the Earth. When rivers and sand dunes meet, the transportation of sediment between them can lead to one of the systems or both of them change. With their connection between river sediment and wind systems there would be lots of reactions, but very little has been studied. According to the previous studies in Iran, river and wind systems have been studied separately. Whereas ground-level processes rarely interact with each other, there is so many important proofs that river and wind processes simultaneously are interacting. The interaction between these two processes is important for mantaining the purposes of an intergrated management of fluvial and aeolian systems, considering the wide vastness of Iran’ s effect by wind and river erosion. This research is the first inventory of interactions between rivers and sand dunes with the aim of systematically analyzing of the interactions between fluvial and aeolian geomorphology and determining the dominance of Fluvial and aeolian systems in different environments....

Considering its Gobiidea and feeding fish sturgeon Caspian Sea highest main and the need to fecundity this fish, this study was done in Babolroud and Tajan rivers in Mazandaran. In order to conduct the study, 197 Sand goby we were caught using an Electros choker machine (V300-200) in the spring of 1390, which was the spawning season, at the Tajan River (Sari) and Babolrood (Babol).103 fish which had not spawned were analyzed. According to the results of the study, the highest average standard length of fish 96.99 ± 1.43, body weight 25.01±9.83 g, gonad weight 1.39 ± 1.03 g and absolute fecundity 952.19 ± 8.49 number of egg fish belonged to sand goby in Tjan and the least average of standard length 74.12 ± 1.38 mm, weight 11.03 ± 7.23 g, gonad weight 0.61 ± 0.27 g and 684.53 ± 2.24 numbers of egg were reported for Sand goby on the babolrod river. The maximum and minimum averages of relative fecundity were respectively 76.96 ± 3.65 and 39.39 ± 2.65 Sand goby in Babolroud and Tajan Rivers. The highest mean of egg diameter 1.11 ± 0.28 mm gonad somatic index 7.44 ± 5.05% belonged to sand goby in Babolroud river and the lowest, percentages were respectively 1.06 ± 0.28 mm and 5.66 ± 3.10 for the sand goby in BabolroUd. According to the measured biometrics and fecundity factors of the rivers, there is no significant difference between the two (p>0.05).

In recent decades, various formulas have been developed to achieve a better evaluation of the characteristics of rivers and natural channels. In this article we compare some of well-known classical methods in estimating stable sections are compared. Also two non-linear functions have been used to design the width and depth of canals and sand bed rivers with the formulations which have been obtained from 70 natural canals in North-America. Genetic Programming (GP) and Group Method of Data Handling (GMDH), two methods in soft computing family, have been used in this research.Finally these methods have been compared with three general methods in designing stable canals. In this modeling, in addition to flow parameters like discharge (Q), sediment quality as average bed particles diameters (D50), and channel slope (S) have been used. The results show that GMDH is more accurate than other methods. Finally sensitivity analysis has shown the effect of each parameter used in the best model.

Background: Rivers are having a major role in crop cultivation, power generation, and sand used for mining and construction. Materials and Methods: The gamma ray spectrometer was used to estimate uranium, thorium, and potassium (238U, 232Th, 40K), and its average is tabulated. Related parameters like absorbed dose (D), Annual Effective Dose Equivalent (AE), and also hazard indices (H) to assess radiation exposure. Additional parameters like radium equivalent (Req), radioactive heat production (RHP), Excess Lifetime Cancer Risk (ELCR), Alpha (Iα, ), and Gamma Index (Ig), Annual Gonadal dose (AGD) are computed and correlated with the related parameters to understand radioactive penetration to the living things. Results: This study exhibits the radioactive contaminants in Cauvery are in control by comparing to the world average except for C20. The average radiological risk of the Palar river is slightly higher and site no. 6 shows three times the world average. Conclusion: This radioactive pollution can cause serious health effects for the people living in and around those two sites (C20 and P7) who are highly exposed to radiation, which leads to harmful effects on living things.

Generally, the origin of coastal sands is river basins and influence of dynamic waves and currents along the coastline are distributed. The case study in this research is middle part of the shore line of Caspian Sea between Haraz River and Babolrood with approximate length of 60 kilometers. The purpose of this research is to determine the direction and amount of sand currents that distributed along the coastline. To achieve this goal, wind data, discharge and sediment of rivers and topographic and geological maps, are used as the main tools and data. In addition, during the field work more than 20 samples of sand taken from the shore line and using survey by granolometery techniques. Then analyses by assessment of sands size and the wave characteristics by analytical methods with Gradistat 4.0 software between them, communicate between directions of sand current during the coastline. To control the results, the wave tank model to compare current levels of sand in the swash zone was used. Also to assess the direction of sands movement by the waves along the shoreline sand samples was colored in the selected sites, the amount of their distribution was controlled. The results show that the dominant directions of wave was, West, North West and North, respectively and current distribution caused by sand and towards the East than the average distance from the river mouth sand particle diameter is smaller. Factors such as discharge of rivers and discharge of sediment and resistance of formation in basins determine as directly the volume of transfers of sand along the coastline sensitive.

Appropriate estimates of flows for different return periods are important for floodplain management in designing canal, bridges, culverts and levees. In general, there are two common approaches to determine design flows at ungaged sites: Rainfall-runoff models, which are often costly and time consuming, and regression models, in which design flows of various return periods are related to watershed characteristics such as drainage area, topographic features, soils and climate. In the present study, bank full-geometry data as well as flashiness index are used as effective independent variables in regression models to evaluate design flows relationships at 41 stream flow-gauging sites in Gara-Gum basin of Khorasan-Razavi province located in an arid and semiarid region. The bank full geometry regression is found to be useful to predict design flows and comparable with flow estimates developed by traditional approaches for ungaged sites in the same basin. As, in three stations in this study area, the error in computations, compared with the method of frequency analysis, was 8% for bank full hydraulic geometry relationship.

In this research, the phenomenon of stress relaxation in unreinforced and reinforced sandy soil with geotextile layer has been studied using a large-scale direct shear test. To investigate the effect of shear speed and soil density on the amount of resistance loss due to stress relaxation, two shear speeds of 0.5 and 5 mm/min and two relative densities of 35% and 60%, respectively, loose and medium density, have been used. All samples have been tested in direct shear test under vertical stress of 100 kPa. The results show that the amount of resistance loss due to stress relaxation depends on the shear stress level, soil density, presence of a geotextile layer in the soil and shear speed. In such a way that by increasing the level of shear stress and shear speed and by decreasing the density of sand and also with the presence of a geotextile layer in soil, the amount of resistance loss due to stress relaxation increases.