Spatio-temporal rainfall distribution and trend analysis of upper Godavari basin, India

Abstract

This current research analyzed the spatio-temporal trends and variability of monsoon season and month-wise rainfall for 26 tehsils in the upper Godavari basin (UGB) of Maharashtra, India. An attempt has been evaluated on rainfall data (1998–2023) obtained from the Department of Agriculture, Maharashtra. To assess the basic trends of the rainfall data statistical techniques, i.e., mean monthly and monsoonal rainfall, standard deviation (SD), and non-parametric method such as Mann–Kendall (MK) trend test, furthermore, simple linear regression (SLR) equation has been applied. Rainfall variability has been examined using the coefficient of variation (CV), and analyzed data has been incorporated into the GIS environment to prepare various maps. The MK analysis revealed an insignificant decreasing trend, especially in June, which suggests a declining trend in rainfall quantity. In contrast, an insignificant increasing trend has been noticed in September which interprets that maximum rainfall occurred in this month in the UGB. In the monsoon season, most of the places denoted no trend, while Dindori (Z = 2.51) and Akole (Z = 1.76) tehsils show significant increasing trends but a drastic decline in the Igatpuri tehsil (Z = − 2.65) The rainfall has been seen to increase towards the west due to the block posed by the Western Ghat to the east-flowing monsoon wind. This study also revealed the monsoon rainfall varied between 93% (Ahmednagar tehsil) and 25% (Aurangabad tehsil) and monsoon month-wise maximum variability (154%) at Ahmednagar in September and minimum (29%) at Igatpuri in July. The approach adopted in this paper identified the micro-level rainfall distribution, trend, and variability which will be greatly advantageous for sustainable water resource management.