Prediction of Water Deficit by Probability Models for Varanasi Region in Uttar Pradesh

The water deficit of various frequencies is required for irrigation planning in rainfed areas. The value of water deficit is needed for computing the depth of irrigation for supplementary irrigation to rainfed crops during the dry spell periods. Prediction of annual maximum water deficit value for the same return periods were computed by Gumbel, Log normal, and Log Pearson Type -III distributions and also used as normal distribution. The probability distribution with lowest value of chi-square (X2) was selected as the best probability distribution. The statistical comparison by Chi-square test for goodness of fit clearly indicated that Gumbel distribution was the best probability model for predicting weekly maximum water deficit for Varanasi region.