Morphometric Indication of Dykes Network Control on Drainage Development in the Amaravati River Basin, Northern Maharashtra

Abstract Drainage basin development in hard rock and basaltic terrains is strongly directed by subsurface structural elements, particularly dyke intrusions, yet the quantitative assessment of their influence on drainage organization and geomorphic development remains inadequate in many parts of the Deccan Volcanic Province. The Amaravati River Basin, situated within the Nandurbar–Dhule dyke swarm region of North Maharashtra, represents a structurally complex landscape where drainage patterns appear to be significantly controlled by dyke-induced lineaments. The dominant problem addressed in this study is to evaluate how dyke networks impact drainage morphology, basin geometry, and geomorphic maturity through systematic morphometric analysis. The Amaravati River Basin covers an area of 760.47 km² and contains 64 mapped dykes with a cumulative length of 569.07 km, resulting in a dyke density of 0.75 km/km². The basin exhibits a sixth-order drainage network comprising 2448 stream segments with a total stream length of 2131 km. The methodology integrates remote sensing, GIS-based spatial analysis, and quantitative morphometric techniques. Drainage networks were delineated from topographic maps and digital elevation models and classified using the Strahler stream ordering system. Dyke attributes—including strike, length, thickness, density, and aspect ratio—were analyzed using rose diagrams, histograms, scatter plots, and regression models to understand structural trends and emplacement characteristics.. The results indicate a distinct structural control of dyke systems on drainage morphology. Dyke orientation analysis reveals a dominant East–West to ENE–WSW trend, with a mean strike of N82°, reflecting a consistent regional stress regime during dyke emplacement. Morphometric indices reveal a moderately to highly dissected basin, with a bifurcation ratio of 4.57, drainage density of 2.8 km/km², and drainage intensity of 1.15, indicating structurally guided drainage development. Basin shape parameters—form factor (0.40), elongation ratio (0.71), and circularity ratio (0.36)—suggest an elongated basin configuration influenced by dyke-controlled topography. Relief parameters, including a ruggedness number of 1.49, dissection index of 0.81, and hypsometric integral of 0.47, indicate a late youthful to early mature stage of geomorphic evolution. The study concludes that dyke networks show a leading role in directing stream orientation, basin geometry, and geomorphic development in the Amaravati River Basin, emphasizing the necessity of integrating structural analysis with morphometric evaluation for understanding drainage evolution in dyke swarm terrains.