Study on Drainage Network Pattern and Morphometric Analysis by Using Hydrology Support Algorithm

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Abstract The degree of accuracy in the extraction of the drainage network and morphometric analysis of the basin plays a vital role in assessing geomorphological characteristics and hydrological processes. The extraction of the exact flow network from SRTM-DEM quantifies the drainage network, and morphometric parameters, which is the main objective of this study. The Thamirabarani river basin in Tamil Nadu, India is taken as the study area. The stream order threshold algorithm is used for stream rasterization to get the pattern of the basin’s drainage network. The hydrology-based algorithm uses a different range of threshold values to determine the stream pattern, which is comparable to the stream vectors of the toposheet. The drainage network distribution with a threshold value of 10000 gives many minor streams which imply dissimilarities with the stream network of toposheet, whereas the threshold value of 20000 shows remarkable similarity to an existing river system. The model with threshold 20000 provides a Stranhler-based drainage network with a basin area of 5664.52 km2. The basin is the fifth-order stream network with many lower-order streams. The drainage pattern is resulted in dendritic and sub-dendritic. The morphometric parameters of the basin are evaluated with the help of an aspect, slope, and contour. The slope of the study area is flat in the east and steeper in the west, along the area of Western Ghats. A bifurcation ratio ranges from 1.05 to 2.42, indicating that the drainage network is not influenced by structural disturbances in that area. The comprehensive evaluation of flow patterns along with morphometric properties obtained from this study provides data support for estimation of the volume of water in the basin, reservoir operation, and construction of hydrological structures. Also, this result can be used to compute watershed attributes normally used in hydrologic and water resources studies. The hydrology-based algorithm can be employed in other river basins to extract drainage network patterns.