<p>The article presents a review of studies into the influence of filtration processes on earthen dams and dependence of these cases on the operating mode of reservoirs. Nowadays, there are about 70 reservoirs in Uzbekistan, about 95% of which are controlled by earthen dams. One of the main current problems in these reservoirs is a process of filtration from the dam body. Of course, during operation of these hydraulic structures, it is of particular importance to accurately maintain the curve of filtration depressions in the dam body and study their effect on it. To explore this process, full-scale field studies were carried out and long-term data of the research object were statistically analyzed. To determine the change in the filtration depression curve from the body of the Сhimkurgan reservoir dam, measurements were made (from 2015 to 2023) using data from piezometers of the PK-40 reservoir dam. Findings retrieved from the field studies were processed by means of the Midas GTS NX program, a modern information technology, and the results achieved by the program were further compared with those retrieved from the field studies. The comparison showed that the rate of the filtration process from the reservoir dam is mainly affected by filtration waters from the floor of the structure. This is explained by the picket of the PK-40 dam, when checked according to the reservoir design, it coincides with the previous river bed.</p>