Comparative analysis of two geologically similar and meteorologically distinct river basins of the Peninsular India

Abstract

Morphometric and hypsometric parameters provide insight into the drainage and erosional behavior of a river basin. In this work, the morphometric parameters, planforms, and hypsometry of the drainage basins of two rivers, namely, the Chaliyar River and the Thamirabarani River, originating from the windward and leeward sides respectively of the Western Ghats in Peninsular India were analyzed to compare its drainage and erosional characteristics. Geologically, both the river basins share a common lithology; however, the precipitation pattern in these two river basins is very different. The average annual precipitation in the Chaliyar River Basin is significantly higher when compared to that of the Thamirabarani River Basin. Also, the precipitation season and the temporal distribution of precipitation are different in these river basins. Mann–Kendall trend analysis of annual precipitation data for the period 1990 to 2014 for both the basins did not exhibit any significant trend. Linear, areal, and relief parameters of both the river basins exhibit considerable similarity. Hypsometric analysis of the two river basins showed that both the rivers are in the equilibrium or monadnock stage, implying that erosion is relatively less in both the river basins. From the study, it is concluded that there is no significant impact of precipitation on the drainage and erosional patterns of these river basins, but it was driven by the underlying lithology of the basins.