In order to develop measures for the rational use and protection of water resources, information on the characteristics of water bodies is needed. The flow of water in the river is the most important hydrological characteristic, which is used in various calculations. In practice activities, the determination of the calculated hydrological characteristics is carried out quite often in conditions of insufficient data from hydrometric observations or in their complete absence. This article presents the results of restoring a number of average annual discharges of the Prokhladnaya River, the catchment area of which occupies the southwestern part of the Kaliningrad region. The Instruch River was chosen as an analogue river, which meets the requirements set forth in the regulatory documents. The obtained data on the average annual discharges of the Prokhladnaya River are of great importance, since the Prokhladnaya River basin plays an important role in the water management complex of the region.