Assessing the nature of rainfall variability on hydrological response in Mayurakshi river basin under changed climate scenario

Abstract

Climate Change has become a widely discussed topic world wise. The adverse effects of changing climate on hydrological processes and water resources have received much attention. During the period 2000-2015, there have been significant changes in precipitation in India compared to the last 100 years. This is a sign of climate change in India. A comprehensive and detailed understanding and clear assessment of the impact of climate change on India's water resources is important to reach definitive conclusions. In this present study, spatial-temporal rainfall trends & variability assessment as well as hydrological modelling was done to assess the rainfall variability on hydrological response under change climate scenario. The rainfall variability was analysed by Coefficient of variation(CV),Precipitation concentration index(PCI) & Standard anomaly index(SAI). The rainfall trends were evaluated using the Mann-Kendall(MK),Sen’s slope estimator(SSE)and the ITA method which is a latest technique to detect trends and for hydrological modelling arc SWAT had been used with SUFI 2 algorithm. Highest rainfall was found in monsoon in all rainfall stations and high variability of rainfall was seen in the winter season. The ITA approach is more accurate in recognizing several hidden significant rainfall trends. The hydrological model was calibrated with observed river discharge data for 2011-2013 and validated for 2014-2016,2008-2013 was the warm up period. the values of statistical parameters(R², NSE, and PBIAS) which had been used for evaluating the SWAT model performance analysis where are 0.56,0.61 and -7.9 respectively and in the case of validation, the values are 0.63,0.66, and -14.2 respectively. Based on the calibration and validation findings, the model satisfactorily simulated the streamflow which was observed in the Mayurakshi River Basin. The calibrated model might be used to assess the impact of climate change as well as LULC on water resources in the upcoming days. the findings of this study may be used to plan and manage water resources, as well as analyse and manage the effects of climatic risks such as floods & droughts.