Spatio-Temporal Variability and Trend Analysis of Changing Rainfall Patterns Over Upper Bhima Sub-Basin, Maharashtra, India

Abstract

The objective of the research is to use spatio-temporal variability and trend analysis to examine how the rainfall pattern is changing in the Upper Bhima Sub-basin of Maharashtra, India. To achieve this objective, rainfall data was analyzed for monsoon and annual timescale using CHRS precipitation data. The study considered five agro-climatic zones viz. Western ghat zone, Transition zone I, Transition zone II, Water scarcity zone and Assured rainfall zone within the watershed. This work analyses the pattern, distribution and trend behavior of rainfall for the period from 1983 to 2018. Since more than 85% of precipitation occurs during monsoon, the analysis has been performed for monsoon season and annual average precipitation data. Statistical summary like the mean, standard deviation and coefficient of variation and inferential statistics like linear regression and standardized anomaly were utilized for the analysis. The Mann–Kendall non-parametric test is used to analyze the trend of precipitation in different agro-climatic zones and the Sen’s slope estimator is used to analyze magnitude of the trend. Spatial variation of the rainfall is analyzed and studied in geographical information system (GIS) environment. The effect of changing climate and regional environment on the spatial and temporal variation of rainfall is clearly noticeable in this study. Climate change strongly affects the agriculture activities where irrigation mainly depends on monsoon precipitation. Hence, policymakers and stakeholders should give importance to proper design and adopting area specific approaches to reduce the adverse effects on crop production at regional level. Rainwater harvesting and advancement in present irrigation facilities could be taken as best possible options in the areas having scarce and more inconsistent rainfall.