Development of a method to identify change in the pattern of extreme streamflow events in future climate: Application on the Bhadra reservoir inflow in India

• Published in: Journal of hydrology. Regional studies Vol. 9; no. C; pp. 236 - 246
• Main Authors: Pichuka, Subbarao, Prasad R, Rajendra, Maity, Rajib, Kunstmann, Harald
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.02.2017; Elsevier
• Subjects: Bhadra reservoir; Climate change; Downscaling; Extreme events; GCM; HEC-HMS; SDSM; Streamflow; GCM; Climate change; HEC-HMS; Extreme events; Downscaling; Bhadra reservoir; Streamflow; SDSM
• ISSN: 2214-5818; 2214-5818
• DOI: 10.1016/j.ejrh.2016.12.084

Bhadra basin (1968km2), located in peninsular India, is considered for demonstration. A general framework to assess the impact of climate change on the pattern of daily extreme streamflow events is proposed. Whereas, the impact is confirmed in the recent literature for most of the hydrologic variables at monthly/seasonal time scale, assessment and quantification at finer time scale, e.g. daily, is challenging. Complexity increases for the derived hydrologic variables, such as soil moisture and streamflow as compared to primary hydrologic variables, such as precipitation. The proposed general framework is demonstrated with the daily inflow to the Bhadra reservoir. Different statistical limits of extremes are defined and change in daily extreme pattern (number and magnitude) in the future (2006–2035) is assessed with respect to the baseline period (1971–2000). Demonstration of the proposed methodology with the inflow to Bhadra reservoir reveals that the daily extreme events are expected to increase in number with the increase in the threshold of the extreme. For a particular threshold, the average magnitude of the extreme events in the future is found to be higher as compared to the baseline period. However, for monthly totals the case is not the same − it remains almost similar. The methodology, being general in nature, can be applied to other locations in order to assess the future change in streamflow and other derived variables.