Analysis of rainfall data for storage and irrigation planning in humid south-eastern plain of Rajasthan in India

Abstract

A study was carried out to analyze the rainfall data for storage and irrigation planning under humid south-eastern region of Rajasthan using a time series record for 32-year (1980-2011) periods. It was observed that most of the years under observation were having adequate rainfall for all round the year crop production provided the water were collected during the rainy season. The area received 921.5 mm annual rainfall out of which 92% occurred during southwest monsoon (June-September) season. Of the total study period of 32 years, 19% were drought years, 66% were normal years and the remaining 15% were the abnormal years. The annual rainfall during the period showed negative trend (-6.955 mm/year). It showed decreasing trend (-7.782 mm/year) during the month of August and positive trends with 0.864, 3.909 and 1.192 mm/year, respectively, during month of June, July and September. The analysis generally showed that water deficit appeared during the period of November up till May and rain water was excess during the period of June up till September. During these months, rain water can be stored with the help of rainfall harvesting system. If only 50% of total rain water is collected, it forms approximately 44.16 lacs litres of water on a unit hectare basis of land. This rainfall water will be adequate for all rounds the year crop production with conservation of rain water and judicious use of rain water resources.