As a case study of the Prypiat Left Bank Drainage System of the Chornobyl Exclusion Zone, the probable onset of the multi-aqueous phase of water content in the frame of the full hydrological cycle at the end of 2022 was estimated for the entire region of Polissia. The attributes of such a process are: 1) a relative increase in the total amount of atmospheric precipitation for the period of September-October-November-December in 2022 compared to the same period in previous years within the entire left-bank part of the Prypiat River catchment basin (according to the ERA5 dataset); 2) the increase in the watering rate of the drainage system territory – both the interdam section and the area located to the northeast of the old dam (this is evidenced by an analytical comparison of the results of the thematic interpretation of Sentinel-2 image data for 02. 05.2023 and satellite data acquired by the various sensors for April-May of previous years); 3) the established facts of heavy rains that occurred in April 2023 in the studied region, flooding, submergence of the large areas, freshet in its territory in April-May of the same year.
          As a result, compared to the period 2015-2021, i.e., already after the termination of the permanent operation of the polder pumping station in the area of the left bank polder, in 2022 the level of 90Sr activity, which according to calculations could have been removed with the runoff from this territory, increased significantly – 4 times more as compared to 2021 and 20 times more compared to 2020. Therefore, considering the above hydrometeorological factors, the prediction regarding the increase in the level of 90Sr activity, which will be carried out with the runoff from the area of the left-bank polder to the Prypiat River, both in 2023, and in the following 2-3 years is substantiated.