Abstract <p>Based on the well-known fact of the short-term period of metamorphosis of amphibiotic insects during their emergence directly out of the water body surface, the author proposes a method for estimating the rate of such emergence from lotic systems based on drift collections. The calculation takes into account the area of the bottom site (1 m²) adjacent to the observation section. The problem of the discrepancy between the efforts spent on data collection and the meager volume of data obtained is considered, which is especially relevant when working in small watercourses, where the emergence of some species is scattered and low-intensive.</p>