Impact of climate change on water availability across western ghats

Abstract

The present study entitled “Impact of climate change on water availability across Western Ghats” was taken up at the Energy and Wetlands Research Group, Indian Institute of Science, Bangalore during 2014-‘15 with the objectives of analyzing the changes in surface air temperature and rainfall across the Western Ghats along the Coast, Ghat and Plain regions and visualizing the likely scenario in land use and water availability in two selected basins viz., Karamana Basin (Thiruvananthapuram, Kerala and Sita Basin, Udupi, Karnataka) under the projected climate change scenario. The data required for the study were obtained from the Directorate of Economics and Statistics, Government of Karnataka, website of NOAA, website of Hydrology Department, University of Princeton and from the publications of the Central Government Department and the concerned State Departments. The study revealed that the rainfall over the Western Ghats as a whole doesn’t reveal any trend from 1901-2010 while it is not so at the regional level. However, the maximum and minimum temperatures along the Western Ghats showed an increasing trend from 1948- 2010. The trend was similar at regional level except in the plains of the Northern Western Ghats which showed a marginal decrease in the mean maximum temperature. Both the representative river basins viz., Karamana in Thiruvananthapuram district and Sita in Udupi district have undergone changes in the land use pattern which altered the water balance of the basin along with the change in population since last two decades from 1990 to 2010. The Karamana Basin suffered a deficit in the available water owing to the low rainfall received in the basin in comparison to the huge demand of water and the situation tend to aggravate with an increase in water demand and decrease in rainfall over the basin. But, Sita basin receives abundant rainfall which caters to the needs of the basin which rules out the water deficit in the basin unless in case of occurrence of moderate to severe drought.