The article deals with the study of the dependence of return collector-drainage water from the large irrigated areas on the volume of water withdrawal for irrigation purposes and the total area of crops. The task is solved in the context of irrigated lands in the Bukhara region of Uzbekistan. Three variants of calculation were performed using an objective method of equalizing and normalizing correlations. Equations of normalized regression are obtained that characterize the relationship between the collector-drainage runoff, the volume of water intake from the Amu-Bukhara canal and the area of irrigated land. Their total multiple correlation coefficients are rather high. Based on the third variant of these equations, a calculated nomogram was plotted. The accuracy of the nomogram was assessed. The results showed that it can be used both for calculation and forecast of collector-drainage runoff from the large irrigated land areas in arid zones.