Probability analysis of annual rainfall and identification of deficit rainfall in left bank canal command of upper Bhima basin of Maharashtra

Rainfall of Pune district of Maharashtra is highly variable and about 80–90% of precipitation falls in monsoon period resulting in frequent drought and flood situation. Therefore, probability analysis of rainfall is essential to know the distribution and behavior during critical crop growth period for optimal crop production. Dependable rainfall at different probability levels (20% to 100%) of monthly rainfall data of 13 raingauge stations of the left bank canal command of Upper Bhima basin viz., Urali, Loni Karbol, Kasurdi, Taju Project, Yewat, Dahitane, Bhigwan, Madanwadi, Pondewadi, Kedgaon, Patas, Pimplegaon and Daund for the period from years 1975 to 2002 was conducted. Further, the dependable rainfall at 20% (Pwet), 50% (Pavg) and 80% (Pdry) probability have been used to calculate the deficit rainfall in each station from January to December and it is observed that cumulative maximum deficit rainfall recorded at Pimplegaon of 563.50 mm/year (maximum deficit rainfall of 187.30 mm month⁻¹ noticed in 07) and cumulative minimum deficit rainfall recorded at Patas of 42.50 mm year⁻¹ (minimum deficit of 0.02 mm month⁻¹ has been recorded for the station Patas in 02). Annual dry year rainfall and annual dry year effective rainfall for each sub command viz., BM48, BM49, BM50, BM51, BM61 and BM68 falling in canal command were calculated and result showed that maximum dry year rainfall and corresponding effective rainfall of402.70 and 355.80 mm respectively were observed in sub command BM50 and minimum in BM61 as 228.90 mm and 208.90 mm. From this study, it has been concluded that due to uncertainty of rainfall, probability analysis and dry year rainfall would be able to provide a guideline for efficient irrigation water management and irrigation planning in canal command under moisture stress situation through adoption of improved moisture stress varieties and proper crop selection which facilitate to moisture enhancement during critical growth stages of crops under rainfed situation.