نوع مقاله : مقاله پژوهشی
1 دانشیار ژئومورفولوژی، دانشکده جغرافیا، دانشگاه خوارزمی
2 استاد ژئومورفولوژی، دانشکده جغرافیا، دانشگاه تهران
3 استادیار ژئومورفولوژی، دانشکده جغرافیا، دانشگاه تهران
4 استادیار اقلیم شناسی، دانشکده جغرافیا، دانشگاه پیام نور سقز
5 دانشجوی دکتری مخاطرات ژئومورفولوژی، دانشکده جغرافیا، دانشگاه خوارزمی
عنوان مقاله [English]
Understanding the Attributes and Interactions of Forms and Processes Governing River Systems that Understand the Behavior of Rivers in Temporal and Spatial Bounds The importance of developing conceptual models for the environment is of particular importance. There are rivers. In this study, the stability of the Gadar River waterway based on the Nanson and Knight models is evaluated to evaluate the dynamic behavior of the Gadar river and its effect on the river bed changes based on the Nanson and Knighton designs. The aim of this study. The research method is a descriptive-analytical one. Required parameters were extracted from hydrometer station statistics, fieldwork, topographic maps, land use maps, Google Earth application and Auto Cad, WMS9.1, Smada and ARC GIS software. This model divides the Anabench rivers into six classes based on flow power parameters, bed load size, particle size, lateral displacement, islet length to channel ratio. In the range of type five and index of the degree of coherence and vertical increase of islands and sinusoidal ducts are in the range of type one. The islands have grown more rapidly in the arterial and direct intervals because of the greater widths than in the other, and in the Meander interval between the Kiel-Sheen heights to the low-lying village. In the third period, the sediment type of the riverbed and the valley where the river flows is erodible and the width of the riverbed is high, but in the first period, the sediment and bedrock are of the erosion resistant formations. Either there were fewer river changes or very little change. The Gadar River is similar to any of the six tributary tributary rivers and, in general, this channel is not fully coherent with the Nanson and Neyton designs.
Rivers are one of the best geomorphic landscapes of the earth, where the link between the system of forces and the forms of roughness can be clearly understood. Studying the morphological pattern of rivers is essential for understanding current conditions and their potential for future changes, and only then can their natural responses to natural changes or actions resulting from the implementation of remediation schemes be possible. It predicted the direction and fixation of the edges and recognized the extent of their displacement and variations in their dimensions and patterns. In the northwestern part of the country, developed river systems play an essential role in the geomorphological developments of the region. The study area is located in the city of Ashnoye in northwest of the country. The purpose of this study was to investigate and evaluate the dynamic behavior of the Gadder River and its effect on river bed changes based on Nanson and Newton designs.
Data and Methods
The research process involved collecting data, field studies, generating information layers and adapting them to the status quo, analyzing each layer to investigate the role of the Gadder River morphodynamics in canal stability and evaluation based on the model. Nanson and Nathan. To evaluate the Gadder River based on this model parameters such as flow power, bed load size and size, particle size of the boundaries, lateral displacement ratio, islet length to channel width, coherence rate and vertical islet and channel sinusitis Used. Finally, the role of each of the variables was identified as influencing factors in the stability of the Gadder River.
Results and discussion
In areas where the conduit turns into an anchor, the slope of the upstream stream is minimized and changes noticeably. At the end, when the slope decreases sharply, the river changes into an arterial one. More than 95 percent of the coarse-grained sediments are due to the high river discharge to carry the coarse-grained sediments and to the greater adhesion of the riverbanks that are prone to coarse-grained sediments.
The erosion of the river bed (Push Abad village to Darband village) was also observed in the sections where the sediment type was erodible (third interval). In areas where the sediment type is bedrock-resistant, there have been fewer or very minor river changes, such as the first section. The arterial and direct intervals have increased more than other intervals due to the greater width and in the meandering interval between the Kilehin heights to the village of Hazrat Zaza. The fluctuations and changes in the sinocyte coefficient of the river Gadar were lower in the first interval due to the first mountainous interval due to the river route. In the second and third intervals, the rate of sinocytic coefficient increased in the year 1396 compared to the year 1395, indicating a complex increase in the rivers in these two intervals, resulting in a change in river morphology in these intervals. The comparative results based on the evaluation and the parameters of the Gadder River in different types of design indicate that the Gadder River has similarities with each of the six types of Anabench rivers and, in general, this channel coincides with the Nanson and Knighton designs. Do not match perfectly.
The Gadar River islands have grown more in arterial and direct intervals due to their greater width than in other meandering intervals, between the Kileen Heights to the lowland village. In the third period, the sediments of the riverbed and the valley where the river flows are erodible and the width of the riverbed has been displaced for most of the length of this section about 10 to 15 meters. However, during the first period, the sediment type of the riverbed is a type of erosion resistant formations. In the specific and local formation of this anterarchic arterial pattern, neotectonics played the most important role as a locus-setting regulator. The locally developed set of these factors has been a factor in the complete non-conformity of the Gadder River with the Nanson and Newton designs.