Drainage Morphometric Analysis of the Nagavathi Watershed of Dharmapuri District, Tamil Nadu, India Using SRTM Data and GIS

GIS and Remote sensing have proved to be a resourceful tool in the explanation of drainage pattern for water resources management and its planning. The identification of morphometric characteristics based on a Geographic Information System (GIS) was carried out in the Nagavathi watershed, Dharmapuri District. The quantitative drainage morphometric parameters was carried out for the Nagavathi watershed by estimating their (a) Linear aspects like Stream number, Stream order, Stream length, Mean stream length, Stream length ratio, Bifurcation ratio, (b) Aerial aspects like Drainage density, Stream frequency, Texture Ratio, Elongation ratio, Form factor, Circularity index, Length of overflow, Constant of Channel maintenance, Drainage texture, Compactness coefficient and (c) Relief aspects like Basin relief, Relief ratio, Ruggedness number, Gradient ratio, Melton ruggedness ratio, Slope,  relative relief, Shape Factor and Leminscate.  The drainage area of Nagavithi watershed is 482 sq. Km. the main drainage patterns is dendritic to sub-dendritic drainage. The Nagavathi watershed was classified as a fifth order drainage watershed, whereas micro watershed was classified as an eight in the watershed. Stream order of the watershed was predominantly controlled by structural and lithological controls of various drainage patterns and their stream orientations were identified to evaluate the direction and controlling factors in drainage network. The drainage density in the area has been found to be low which indicates that the area possesses highly permeable soils and low relief. The bifurcation ratio varies from 0.8 to 43.1. The elongation ratio of  Microwatersheds  varies  from  0.13  to  0.43, indicates  Microwatersheds  fall  under elongated  pattern. This study would help the local people to utilize the resources for planning rainwater harvesting and watershed management