Climate Change Impacts on Extreme Flow Measures in Satluj River Basin in India

A major impact of climate change is likely on the frequency and magnitude of extreme flow events. Hydrological systems have traditionally been designed on the assumption that the available flow records for a location reflect stationary climatic conditions. In view of the recent climate change, the assumption of stationarity in the flow records cannot be justified. Design of hydrological systems is, therefore, likely to be more reliable if the impacts of potential climate change on extreme events are considered. This paper investigates trends in extreme flow measures for a set of streamflow gauging stations in Satluj River Basin in India. Linkages of extreme flow measures with large scale climate indices have also been identified. The analysis includes an exploration of the types of trends that may occur in an extreme flow record, which include changes in the timing of extreme events, and changes in the extreme event magnitudes. Several extreme flow measures including the high flow and low flow magnitudes and their dates of occurrence have been analyzed for the detection of trends using Mann-Kendall non parametric test. The results reveal more trends than would be expected to occur by chance for various measures of extreme flow characteristics. The data has been found to exhibit changes in both the magnitude and the timing of extreme flow events. Analysis of extreme flow measures presented herein is likely to lend credibility to recent climate change modeling efforts, and would help detect climate change impacts on hydrological regime.