Eco-Hydrological Footprint of a River Basin in Western Ghats

Conclusion

Kali River catchment physical integrity is altered with the implementation of unplanned developmental projects such as the construction of series of dams, Kaiga nuclear power plant, Dandeli paper mill, etc. leading to large-scale land cover changes evident from the decline of forests from 84.6 percent (1973) to 54.9 percent (2016) and the reduction of evergreen forests from 61.7 percent to 38.5 percent. These structural alterations of the land-scape in the basin have altered the natural hydrologic regime. Assessment of water footprint indicates the re-quirement of 2309 million cubic meters for the societal and livestock demand, 3779 million cubic meters for ter-restrial ecosystems, and environmental flow of 987 mil-lion cubic meters (to sustain aquatic biota). The terrestrial demand is met by percolated water in the hypo-morphic zone, supply in the basin would be function of surface and subsurface flows which accounts 3292 million cubic meters. Eco-hydrological footprint emphasizes the role of forests on infiltration and evapotranspiration capabilities. Sub-basins with higher forest cover had higher eco-hy-drological index supplementing that the availability of water can satisfactorily maintain the demands, where sub-basins dominated by monoculture had low index indicates water scarcity. Hydrological footprint shows sustained water supply catering societal and environmen-tal demands in the catchment dominated by native forest cover of endemic flora. Inter-annual variability of supply and demand footprints indicate that the sub-basins be-tween coasts and Ghats are with perennial river streams, whereas the transition zones between Ghats and plains towards the eastern portions showed a deficit of water for 6 to 10 months with intermittent and seasonal flow. Occurrence of streams with 12 months flow in the eco-logically sensitive region (1 and 2) confirms of linkages of hydrologic regime with the ecological sensitiveness of a region. This highlights that streams are perennial in the catchment with forest cover > 70 percent and with higher endemic plant species confirming the linkage between ecology and hydrology with the land use dynamics in the catchment. This provides invaluable insight to the need for integrated approaches in the river basin management in an era dominated by mismanagement of river catch-ment with the enhanced deforestation process, inappro-priate cropping, and poor water efficiency. The premium should be on conservation of the remaining evergreen and semi-evergreen forests, which are vital for the water se-curity (perennial streams) and food security (sustenance of biodiversity). There still exists a chance to restore the lost natural evergreen to semi-evergreen forests through appropriate conservation and management practices. Current management practices adopted by 20th century civil engineers has been contributing to the erosion of water retention capability in the catchment with severe water scarcity, evident from 279 districts in the country reeling under droughts during the last three consecutive years. The current study provides insights of the role of forests with native species in maintaining the hydrolog-ical regime while sustaining the local demand, which is useful in the watershed (catchment / basin) management by the respective government agencies.

 

 
Citation :T.V. Ramachandra, S. Vinay, S. Bharath, A. Shashishankar, 2018. Eco-Hydrological Footprint of a River Basin in Western Ghats. Yale Journal of Biology and MEDICINE 91 (2018), pp.431-444.
* Corresponding Author :
Dr. T.V. Ramachandra
Energy & Wetlands Research Group, Centre for Ecological Sciences, Indian Institute of Science, Bangalore – 560 012, India.
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