Hydrological impacts of climate change in a humid tropical river basin

Cheangath Gangadharan Madusudhanan, T.I. Eldho, D.S. Pai

Wednesday 1 july 2015

8:45 - 9:00h at North America (level 0)

Themes: (T) Extreme events, natural variability and climate change, (ST) Hydrological extremes: floods and droughts

Parallel session: 8I. Extreme events - Flood Drought

Humid tropics are extremely vulnerable to climate change due to the fragile and diversely rich ecosystems and high human dependence. This becomes exacerbated and confounded in river-delta regions where both natural and human systems have limited adaptive capacity. The present work looks into the hydrological impacts of climate change in an unimpaired river basin in the Western Ghats of South India. The applicability of a macroscale land surface, Variable Infiltration Capacity (VIC), model in assessing the hydrological impacts of climate change in a high rainfall tropical river basin is investigated. The model is validated at a finer resolution of 0.25 degree and is found to be skillful in simulating the observed runoff at daily scale. The model is calibrated with detrended climate data and is further used to assess the hydrological impacts under a given landuse. The study highlights sensitivity of the hydrological impacts to temporal scales. However, the observed changes in the climate has insignificant impact on flow regimes at all temporal scales. The drastic change in the baseflow regime has wider implications for agriculture, industry, aquatic life and overall water availability in the region.