Investigation of Fractal Dimension Variations on Basin Characteristics (Case Study: Shirkuh Yazd Watersheds)

Fractal geometry, known as the mathematical language of nature, can serve as an appropriate quantitative tool for studying various geomorphological phenomena and modeling numerous complex natural features. The primary fractal characteristic analyzed in this context is the fractal dimension, which is significant for understanding behavior and predicting changes in different geomorphic features. The purpose of this research is to determine and analyze the fractal dimension using fractal geometry theory and the Horton-Strahler branching method in three watersheds of Shirkuh Yazd region. For this purpose, formations present in the region, including shale and marl, limestone, and granite, were initially classified, and their fractal dimensions were determined at various resolutions. Consequently, each watershed and its subsidiary branches were ranked, and fractal dimensions were calculated based on branch lengths. The results indicated that the fractal dimension could be effectively utilized to assess changes within basin formations. Specifically, findings revealed that among the studied watersheds, the highest fractal dimension belonged to the shale and marl formations. The fractal dimensions calculated at size one with a resolution of ۳۰۰ dpi were ۱.۷۵۰ for shale and marl, ۱.۷۴۶ for limestone, and ۱.۷۳۶ for granite formations, respectively. Additionally, an increase in size and resolution led to an increase in the basin fractal dimension, though this change maintained a constant ratio across different basins. Thus, it can be concluded that the fractal dimension can be employed to distinguish various geological formations within a watershed.

Keywords:

Drainage network , Marl , Fractal , Geomorphology , Horton , Geological Formations