Rivers have a complicated، various condition in the diverse environment as studied by hydrology، geomorphology، hydraulics، ecology and engineering. River geomorphology studies the river process and landforms and examines the evolution of the river''s landscape، which can play an important role in identifying river channel characteristics and behavior. Designs with river engineering enable precise examinations of rivers leading to declines in property damage. In this study we initially determined the type of river style. Then، with three degrees of freedom، the channel morphology، plan form، river bed characteristics، capacity for adjustment، and relevant geoindicators for each degree of freedom for each river style were determined. Next، we interpreted the river''s evolution by using ergodic reason to assess whether irreversible geomorphic change occurred. The geomorphic recovery potential of each reach was determined by assessing the connectivity of the reaches and interpreting limiting factors and pressures. In the LavijRud catchment eight river styleswere identified. More steep headwaters have intact condition and gorges، low sinuosity planform with discontinuous floodplain and high energy with gravel bed river styles have a high river recovery potential. Cut-fill، bedrock controlled with discontinuous floodplain and confined with occasional pocket floodplain river styles have moderate river recovery potential. Confined with slump bank river style have a low river recovery potential and their conditions are degraded. Results show that river styles in this catchment also have respectively 65% high، 28% moderate and 7% low river recovery potential. Management prioritization of each river style observed the river''s geomorphic conditions and recovery potential.

Morphological river models are designed to provide physical insight into the morphological response and to assist river engineers and managers in the design, operation and maintenance of river systems. Here deterministic modeling weak for a dynamic and stochastic of nature river environment. Specially, these could not predict the exact shape of the river bed, Specially e.g. for braided river because the bed level variability and variations in cross-sectional. Since a stochastic model approach copes with the variability of system behavior of the time, therefore need for Stochastic modeling on the location of morphological changes in rivers and variations in river bed seems necessary. Many large rivers in the world have recently undergone through a great deal of morphological changes, Which has led to the development of local scouring, therefore, it has become an important problem for the river engineering. The change of river morphology is evaluated by braid parameter in braided rivers. A decrease in braid parameter results in a braided channel changes to meandering. As a result, local scouring process is accelerated. Since Process of the changes in river cross section are usually caused by change in water and sediment discharges or by river works. Moreover, river gradient plays a key role in channel morphological changes therefore In this research, local scouring relationship with river morphologic changes are investigated by stochastic modeling in braided rivers based upon for parameters such as maximum water, sediment discharges, river bed gradient river and bed elevation. The model was then tested by data obtained from Yahagi river in Japan. That the month Maximum Stream flow data is predicted by time series models (ARIMA) and three sediment transport equation were used to calculate the bedload such as Bagnold, Meyer-peter and Einstien Brown. predicted results show If calculate the bedload with the Bagnold equation, this model could predict significantly in cross-sectional and local scour depth, predict river morphological changes.

In current effluent discharge standards of the most countries such as Iran, self-purification capacity of rivers have not been considered. These standards developed a similar effluent discharge standard for all of the rivers without considering hydrological and hydraulic conditions of rivers.
In this paper in order to show the importance of self-purification capacity and differences between the rivers, in developing effluent discharge standard, two rivers- Gheshlagh River in Kurdistan and Sabzkooh River in Chaharmahal Bakhtiari- as samples were selected., and with applying Qual2kw model, current Iran effluent discharge standards were used to simulate the state of each river. The simulation showed that compliance with this standard maintain an appropriate qualitative condition of Gheshlagh River but in Sabzkoh River, due to the large number of pollution sources, these standards not only does not help to maintain the water quality but will have a very negative impact on water quality. Then Using simulation of river quality, the authorized appropriate limit based on self-purification capacity and the number and type of pollutants were estimated and showed that to develop accurate and efficient standards the self-purification capacity, the number of pollution sources, the amount of waste load and other different conditions of rivers also should be considered.

Since the ownership of border rivers is not entirely in the hands of a certain country, exploiting and employing these rivers have been always a controversial issue within many governments. Hirmand Border River which originates from Kabul West Mountain and pours into Hamoun pond after traveling 1050 Km has been of the legal issue between Iran and Afghanistan since assigning the Paris agreement in 1857.
This paper seeks to answer this question that what are the legal aspects of exploiting Hirmand River, and what principles dominate the international rivers in terms of international law? Thus, based on different approaches to the dominant lawful regime on international rivers, the present paper based on statutory rules, practice and votes of international courts, and government approachesaims to recognize the dominating principles on international rivers and apply them to Hirmand River. Ultimately, this study suggests that the international law principles of international rivers have accepted “the principle of limited territorial sovereignty” on international rivers. And in accordance with international laws principles, rivers whose basins are located in another country, the upstream country cannot change or drift the route of that river or any other act which does harm to downstream countries.

River terraces are important components of natural landscape, and among the key elements in the study of geomorphic features of river phenomena in regional and local scale as well as trend of river power changes in relation to different factors in the course of time. These phenomena, as river forms, represent the level of flowing waters in the past and river performance in response to changes in the characteristics of several factors. Regarding the activity of processes. and influenced by changes and disturbances in conditions, the river sometimes has to cut its bed and create benches parallel with its longitudinal profile. The river terraces, which provide successive changes in beds of river flows, are in fact considered the best means for surveying the past history of regions in terms of the type of changes and rivers’ reaction to such changes in different times. Considering such an important feature, these phenomena are among the topics discussed in different sciences of the earth, especially geomorphology and soil science. For soil sciences, the terraces are: smooth surfaces with mild slopes formed by heterogeneous pebbles whose presence along the rivers provides a relatively stable place for soil formation. For geomorphology, river terraces, as the most important geomorphologic forms, are results of the operation of water flows which have been formed by fluctuations and changes in various factors, such as changes in the energy of morphodynamic factors. River terraces formed and developed by alternation of the processes of destruction and sequestration in the rivers are usually seen as slope cuts on either side of the rivers’ banks or only on one side of them. Generally, it can be said that the formation of terraces around the bed of rivers suggests adjustments and changes in longitudinal profile of rivers in response to changes in the type and amount of exchanges related to the location, special time and evolution of longitudinal profile of river in order to adapt to the new conditions. Despite the importance and major influence of tectonic activities on river alluvia and formation of terraces, research in this area has been very trivial. The difference in the shape of channels and variation in the response of rivers to such activities (due to difference in flow rate, type and amount of bed load) have possibly been the main reasons for complexity of the subject and, as a result, a decrease in the number of studies in this field

The new and modern scientific field of river engineering integrates hydraulics with hydrology-geomorphology and investigates and discuss water movement in rivers. In order to prevent damages caused by river flood, probable floods must be predicted using appropriate methods. Moreover, identifying river morphology (river erosional landforms) can help us noticeably in recognizing and preventing damages.
The present article identifies erosional landforms in Chenar-e Rahdar River and produce a map for different forms of river erosion using geographic information system, remote sensing and dispersion of different erosional landforms in this river along with sedimentation areas

Introduction The Monitoring on route changes trend and geometric pattern of rivers is essential for identifying and evaluating eventual problems and risks in order to maintain and optimize utilization of natural resources and it is among the priorities of Geomorphology Studies. The purpose of this study is analysis of affecting factors in Kalghan Chai River and Assessment of river power and effects on the river morphology influenced by human actions is changing the river shape. The Kalghan Chai Basin is part of the Ghezel Ozen basins, which is the Garango River is its main drainage. This is located at the position 28° 46 to 30 46 east longitude and 34 37 to 46 37 north latitudes on the eastern slopes of the Sahand Mountains. In this research, studied region is range between Kalghan Dam to connect Garango River.

Material and methods In study in order to achieve research goal were used techniques and different methods, materials of research are include of Satellite Image, Topographic map, Geological map, flow Hydrological data, data provided from Dem and field data. In this research were used methods of River Power Analysis, River specific power, Sinuosity Index, Central angle, Route Sinuosity in order to channel pattern and dynamic analysis. In order to study the river power and its effect on the erosivity, River discharge was calculated in different return periods. Then the river power was calculated by the following equation: The flow power can also be expressed in units of the bed surface if the width of the river (W) is divided, Therefore, in order to express the power of the river at any point, it is necessary to calculate the special power of the river, is calculated by the following equation:ω=γQS/W
To study the shape and pattern of the river, coefficients Sinuosity Index, Central angle, Route Sinuosity were used. Then the Sinuosity Index size for each arc was calculated by the following equation:The center angles of the arches on each of the intervals were calculated using the following equation
The sinuosity of the river route was also calculated using the following equation:
Results and discussion The analysis of the characteristics of river meandering on the basis of Sinuosity Index showed that the Sinuosity Index of the study area was 1.31. And more than 90% of the curvature range is from 1.05 to 1.5, and the curvature is more than 1.5, 89% of the meandering of the study area. There are no curvatures of less than 1.05 and no more than 2 in any of the studied meanders. Therefore, the pattern of the river in study area is sinuosity. The sinuosity analysis of the river interval also showed that of the 20 interval studied, there is no Meandering interval, And 7 interval are straight pattern the rest of the interval has a sinuosity pattern. River Power Analysis showed which has the maximum River power of the Sections 20, 21 and 22, the lowest of river power are at Sections 11, 12, 13, 14 and 15. The lowest of specific river power in the sections of 19, 21 and 6. And the maximum river power in the section of 9.
Conclusion Results indicated that forming of channel pattern and dynamic in studied area was controlled by hydrological processes cased flow and sediment discharge, lithological resistance of river bed and sides and the role of human factors for capture and occupation of the river bed to create gardens and farms as well as at some sections the main factor shaping is the Chanel of removal of sand from the river bed. The results of flood power and specific power analysis showed by reducing the width of the river crossing, river power increases, and the flood power depends on morphological characteristics of the river The results of this study can be used to identify of interval Maximum River power and interval affected by river erosion.

Every natural river has an capacity to assimilate wastes; this is referred to as the river's self purification capacity. DO content is usually an important water quality index. The water quality of a polluted river can be improved either by increasing the river's self purification capacity or by reducing the amount of waste loading the river receivers. Traditional physically based water quality models do not evaluate separately a receiving river's purification ability and the effect of waste loading; thus, these models are not ideal analytical tools for water quality management. This paper introduces and discusses an alternative river water quality modeling approach based on the linear systems theory. Steady-state-system response matrix is a means to summarize the interactions of loadings and responses for linear water quality models. BOD-DO variation in a receiving river has been investigated by following traditional physically based water quality models. A simple physically based river BOD-DO model was derived by Streeter and Phelps (1925) based on their Ohio River water pollution study. The Streeter-Phelps model has been used by sanitary/environmental engineers for many years to evaluate the waste assimilative capacity of a receiving river; it provides a basis on which the treatment requirement for wastewater discharged into the river can be determined. The BOD-DO variation in a time-variable river system with a dispersive effect is traditionally solved by numerical methods. In this study, physical parameterization method is used. Using this method, the system impulse response function of a receiving river can be determined by solving the governing equation of the corresponding physically based model with a Dirac delta function input. This modeling approach is an extension of Green's function techniques that solve a linear differential equation. In a linear systems model, a receiving river's patura-purification capacity is represented completely by the model's impulse response function, whereas the amount of waste loading the river receives is represented by the model's input function. The Enhanced Stream Water Quality Model (QUAL2E) is a comprehensive and versatile stream water quality model. In this paper a river was simulated with QUAL2E. Then a response matrix was built for determination of DO deficiency in any point of river.

Rivers as one of the most important sources of fresh water consumed industrial, agricultural and urban areas have special importance. Challus River as one of the rivers of Mazandaran province residential areas and agricultural pass and eventually flows to the Caspian Sea is of importance. Therefore, comprehensive research done about the pollution in terms of quantity and quality and use of management tools such as mathematical and computer models to determine the trend and forecasting river water quality and pollutant load to determine the damage and offer solutions for improving the quality of the type. In this study, the measured data and statistics about the water quality at four stations of the river and compare them with existing standards status of this river were studied. Self-purification river model with soft ware QUAL2K New Profile quantitative and qualitative input river and wastewater in the two low water season and high water, was built and calibrated. Then it convey wastewater to the standard profile (with respect to effluent discharge standards, the Department of Environment) discharge to surface waters of the river with the new situation use its software and the user in different areas and rivers were determined to limit its quality standards available for agriculture, livestock and seafood consumption. The result was the conclusion that power has been low river Self-purification increase in organic nitrogen wastewater with new is of considerable. The results indicate that the Self-purification of river low by increasing organic nitrogen influent wastewater. Also, by increasing of inorganic phosphorus during the rise of water level in the river phosphorus and organic phosphorus river water. The nitrate level in the river during high water season which decrease trend due the dinitrification and release of N2 is. But in low water season nitrate initially fixed at the end cause influx of sewage to where the base flow is low and pollutants will be increased. While low levels of nitrate indicate that it was contaminated by fertilizers discharge into the river. The main problem at the end of the river in new modeling and urban domestic waste water was diagnosed. Creation of networks residential wastewater and to introduce the treatment methods keep the river water quality to be safe.

Kashkan River is one of the important and water logged tributaries of Karkheh River which collects waters of a vast area of ​​Lorestan province. This river at the south-west part of Poldokhtar in a region known as the Gel-Sefid River is joined to Seymare River and creates Karkheh River. Length of Kashkan river is about 270km، and the water basin area of this river at upstream of Kashkan - Poledokhtar station is 9400 km2. This river due to its morphological and meandering characteristics and even in some floodplain points is arterial. There exists the problem of side erosion and displacement of river plan. Since، finding the appropriate technical method requires the recognition of the river behavior and effective geometric and hydraulic factors on the erosion and sedimentation process، therefore in the present research، topographic maps and satellite images have been used for reviewing and studying the temporal variations of Kashkan river plan. For this purpose، through performing a field survey and comparison of the new and old plan of the river by GIS software، the variation of river was investigated during a 52 years period and critical periods waere identified. Also the meander characteristics of the river and development rate of meandering in the current status in 49 of river bends at the reach of 108 km، between Varpo; and Teymorabad were investigated. The results showed that 6% of bends are undeveloped، 51% are developed and 43% are more developed. Finally، with respect to the geometrical characteristics of the river and using empirical relationships، the rate of bank erosion at critical reach in the future was anticipated. The prediction results show that at، Upper Kalho and Chrkhstan، river will move 657 m. Also at Khatere، Doab، Dovale Bozorg and at upstream of Chame Pelk، its movement will be 1035m and 1297 m respectively to stabilize it naturally.