Modeling, Probability Analysis and Forecasting of Rainfall in Betwa River Basin in Bundelkhand Region, India

Abstract

Daily rainfall data of 41 years (1975-2015) of MP and UP districts covered under the boundary of Betwa river basin of Bundelkhand region have been considered to analyse the long term average and its temporal variability on seasonal and annual basis by using MK test and Sen’s estimator, and annual rainfall forecasted by using ARIMA model for five year period from 2016 to 2020. The average annual rainfall in the Betwa river basin was 958.6 mm with 25.1 percent coefficient of variation indicating thereby that the annual rainfall was not much stable over the years. Upper to middle region of basin received more average annual rainfall than middle to lower region of the basin. Hamirpur, Tikamgarh, Raisen, Bhopal, Shivpuri, Chhatarpur, Jalaun, Mahoba, Ashoknagar, Lalitpur, Sagar and Vidisha annual rainfall time series shows negative trend while Jhansi annual rainfall shows positive trends. These trends are tested for seasonal rainfall for districts seasonal rainfall at 5%level of significance. All station shows insignificant positive and negative trend in winter season rainfall followed by pre monsoon, SW monsoon and post monsoon season rainfall. The rate of decrease in the annual rainfall for districts covered under Betwa river basin except Jhansi varied 1.57 to 13.12 mm/yr and for Jhansi rate of increase in annual rainfall was estimated to be 0.4387 mm/yr. Using Weibull’s (extreme value type III) method weekly rainfall for monsoon season was predicted at 50, 75, and 90 percent probability levels. The average annual rainfall time series is forecasted for the period 2016 to 2020 at 80% and 95% prediction intervals. Results of this study can be helpful in the planning, development and management of present and future plan in the Betwa river basin