| چکیده انگلیسی مقاله |
Introduction and Goal
Understanding the role and influencing factors of soil erosion is crucial for effective management and recognition of erodible land areas. Watershed management is one of the most sensitive and complex types of resource and production management. The fractal dimension can be used to examine the complexity of data and simplify complex natural phenomena. This tool enables generating fractal patterns to assess the morphological behavior and power of watersheds. This research focused on the connection and interplay between the morphological characteristics of the watershed and the fractal dimension in the creation of runoff and sediment.
Materials and Methods
In this research, the necessary data were obtained from the statistics of the country in the water measuring and observation stations of the watershed. The base maps were utilized to determine the watershed characteristics. The calculation of the fractal characteristics was done in Fractalyse 2.4 software by utilizing the box counting method. The factor analysis method was used to identify 85 features related to watershed. In this research, for further analysis, the size of annual runoff and sediment was investigated using different return periods. Therefore, 5 different scenarios were considered based on the homogeneity of the watershed, climatic characteristics, physical and morphological characteristics of the watershed, physical and climatic characteristics simultaneously, and fractal characteristics of the watershed. The correlation between estimated irrigation and sediment size (with different return periods) and different morphological features was also carried out.
Results and Discussion
The results of the factor analysis technique showed that among the 85 parameters related to the watershed, 18 are the effective parameters of the area, the slope area is 8-12 and 12-20%, the area of the east slope in 9 directions, the length of the 100-m level lines in the watershed, the total length of the stream , the concentration time base Kirpich method, elevation difference, fractal of 200-m level lines, deviation from the moisture standard, temperature difference, average slope, net slope of the main stream, average temperature, average moisture, average precipitation, elongation coefficient and fractal of the basin environment. Also, the fractal dimension of the 200-m horizontal lines and the fractal dimension of the watershed environment were able to significantly explain the overall changes in discharge and sedimentation. This finding explained well the role of fractal characteristics in the relationship between irrigation and sedimentation.
Conclusions and Suggestion
Based on the results of this research, it was found that almost all the effective factors in estimating discharge and sedimentation in large watersheds are summarized in the area and fractal of the watershed environment, and these two features justify the most changes in discharge and sedimentation. Therefore, with the reduction of the area of watersheds, the role of other factors such as the direction of the slope, the net slope of the waterway, etc., is more evident in explaining the changes, and it can be said that dividing large watersheds into smaller watersheds is the best measure to control the erosion and runoff of watersheds. Implementing watershed management measures in these small sub-watersheds is the next step. The reduction of watershed area in most relationships is sufficient to justify up to 70% of sediment changes. This research findings should be utilized by users and beneficiaries to implement watershed development and management programs. |