Eco-Hydrological Footprint of a River Basin in Western Ghats

Eco-Hydrological footprint of a river basin refers to the hydrologic regime for sustaining vital ecological functions considering the appropriation of water by biotic components (including humans). It provides crucial information about the ecological status of a river, while addressing the divergence from natural conditions of the actual hydrological regime. Thus, this highlights the implicit relationship of hydrologic regime in meeting the demand of the biota. Unplanned developmental activities have altered the catchment integrity which has threatened the regional water security due to the conversion of perennial streams to seasonal ones. This has necessitated prudent catchment management strategies to maintain the ecological water requirements so as to maintain the aquatic and terrestrial biodiversity and to sustain water resources. The skewed strategies oriented mainly towards societal benefits have led to large-scale degradation of the landscape. Large-scale alterations of the landscape structure have led to erosion in the ecosystem supportive capacity that plays a major role in sustaining the hydrological regime. Insights of eco-hydrological footprint in the catchment would aid in formulating policies to sustain the hydrologic regime and natural resources. The current study focuses on the assessment of the eco-hydrological footprint in the Kali River of central Western Ghats, Karnataka. Land use dynamics assessment using the temporal remote sensing data of four decades reveal decline of evergreen forest cover from 61.8 percent to 37.5 percent in the Kali river basin between 1973-2016. Computation of eco-hydrological indices shows that the sub-catchments in the Ghats with higher proportion of forest cover with native species has a better eco-hydrological index as against the plain. This highlights the vital ecological function of a catchment in sustaining the hydrologic regime when covered with the vegetation of native species. The presence of perennial streams in sub-catchment dominated by native vegetation compared to the seasonal streams in the catchment dominated by anthropogenic activities with monoculture plantations. Eco-Hydrological Status/Hydrological footprint reflected similar results as that of the eco hydrological index demonstrating the role of forests in maintaining the hydrological regime. Inter annual water budgeting across sub basins showed that the Ghats and Coastal areas are sustainable with perennial waters in the river as against the plains in the east which showed deficit of resource indicating water stress.