Morphometric Analysis of Nanjannad Hill Watershed in South India using Geographical Information System

Watershed is a natural geohydrological unit that allows surface runoff to a particular point or outlet, Morphometric analysis plays a vital role in the proper planning and development of the watershed. Morphometric analysis of the Nanjannad watershed is carried out using integrated approach of remote sensing and GIS techniques. The present study attempted to determine the morphometric characteristics of Nanjannad watershed of Ooty, Tamil Nadu. Geographical information system (GIS) is used to evaluate linear, areal and relief aspects of morphometric parameters. The drainage area of the watershed is 434 ha, the watershed is a Fourth-order drainage basin, and the lower order streams are mostly dominating in the watershed. Physiography, rainfall and lithology of the location control the stream orders. The development of stream segments in the watershed area is affected by rain, slope of the watershed varies from 0 to 87%. The mean Rb of the entire watershed is 4.38, indicating that geological structures do not influence the drainage pattern much. The whole watershed elongation ratio is 0.67 showing the majority of the area has Moderate relief and a steep slope, Relief ratio values implies that the discharge of the Nanjannad watershed is high and groundwater potential is meager, the moderate value of drainage density, stream frequency and drainage intensity, indicates that runoff is more likely to cause water logging. This work can be used as input to evaluate hydrology and water resources and will be helpful for integrated watershed planning.