Vol. 12, Issue 7 (2023)

Author(s):
Kamlesh Kumar Sahu, Surendra Kumar Chandniha, GK Das and Harithalekshmi V

Abstract:
The uncertainty in occurrence of rainfall is a serious concern nowadays. There is an urgent need in studying the variability associated with rainfall in the context of changing climatic conditions. Proper understanding of variability of rainfall in spatial and temporal scale is crucial for crop and water resource planning and preparation of contingency plans. Chhattisgarh is an agrarian state where dependency of agriculture on rainfall is having great importance. In this context the spatio temporal variability of rainfall has been analyzed in this study in block level. Monthly gridded rainfall data of the 149 blocks of Chhattisgarh State was collected for a period of 1901 to 2020 (119 years) from the India Meteorological Department (IMD). Initially, long term statistics have been quantified in terms of mean, minimum, maximum, standard deviation, coefficient of variation, skewness, and kurtosis for annual, pre monsoon, south west monsoon, post monsoon and winter season. The spatial maps have been created using Inverse Distance Weighted (IDW) technique of interpolation in ArcGIS 10.6. The study was done at block level which offeres better understanding of rainfall variability over the state. The average annual rainfall over the state from 1901 to 2020 was 1366 mm which ranged from 1094 mm (Chhuikhadan block of Chhattisgarh Plains) to 1620 mm (Jagdalpur blockck of Bastar Plateau). The co efficient of variation of annual rainfall over Chhattisgarh was 24%. Among the four seasons, the maximum rainfall was noticed during monsoon season (1140 mm) with the smallest value of coefficient of variation (24%). The minimum amount of rainfall was seen during winter season (40 mm) while maximum amount of co efficient of variation was seen during pre monsoon season (123%). Among the three agro climatic zones, maximum value of average rainfall was noticed in Bastar Plateau (1482 mm) followed by northern hills zone and Chhattisgarh Plains. The study showed how the annual and seasonal rainfall showed variation over different blocks of Chhattisgarh. The findings of the study gives useful information for effective planning of water resources and crops in various regions of the state.