Climate change impact on fluvial flooding in the Indian sub-basin: A case study on the Adyar sub-basin

• Published in: PloS one 2019-05, Vol.14 (5), p.e0216461
• Main Authors: Ramachandran, Andimuthu, Palanivelu, Kandasamy, Mudgal, B V, Jeganathan, Anushiya, Guganesh, Sankar, Abinaya, Balu, Elangovan, Arunbabu
• Format: Article
• Language: English
• Subjects: Case reports; Climate Change; Climate models; Computer simulation; Earth Sciences; Ecology and Environmental Sciences; Emergency preparedness; Environmental aspects; Environmental impact; Environmental Monitoring; Environmental risk; Flood frequency; Flood mapping; Flood peak; Flood risk; Flooding; Floods; Forecasting; Future climates; Geomorphology; Global climate; Global climate models; Global temperature changes; Greenhouse effect; Hazards; Hydraulics; Hydrologic data; Hydrologic models; Hydrology; India; Intergovernmental Panel on Climate Change; Internet; Models, Theoretical; Precipitation; Predictive Value of Tests; Rain; Rainfall; Rainfall data; Rainfall intensity duration frequencies; Research and Analysis Methods; River basins; Rivers; Social Sciences; Statistics; Watersheds
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0216461

Flooding is one of the most disastrous global hazards, which has been occurring more frequently in recent times. It is observed that climate change is likely to increase the intensity and the frequency of floods and river basins have become more vulnerable to fluvial flooding. In this study, the impact of climate change on fluvial flooding was analyzed over the Adyar sub-basin. This study applied statistically downscaled Global Climate Model (GCM) data in a CMIP5 dataset of IPCC Assessment Report 5 (AR5). Based on the performance to simulate the observed climate, four GCMs, namely, cesm1-cam5, mpi-esm-mr, ncar-ccsm4, and bnu-esm, for RCP 4.5 were selected for projections of the future scenario. The Intensity-Duration-Frequency (IDF) curves for the past and future scenarios were derived from the IMD-observed and GCM-projected rainfall data. Integrated flood modeling was performed with hydrologic (HEC-HMS) and hydraulic (HEC-RAS) models. Finally, in order to visualize the inundation areas according to the future climate projection, flood inundation maps were prepared geospatially using the ArcGIS software. For the 100-year return period, the results predict that the peak discharge for the future climate scenario would increase by 34.3%-91.9% as compared to the present climate scenario. Similarly, the future projections show an increase in the flooded area ranging from 12.6% to 26.4% based on GCMs. This simulation helps in understanding the flood risk over the Adyar sub-basin under the changing climate and the requirement for the regulation of developmental activities over the flood-prone areas.