О климатобусловленных и антропогенных изменениях взаимодействия поверхностных и подземных вод в Центрально-Черноземной зоне России

The ongoing climate warming is leading to changes in groundwater supply and discharge into rivers. In the Don River basin, the influence of various anthropogenic factors is added to the climate-related factors of surface and groundwater interaction. These include presence of tens of thousands of ponds in the upper parts of the hydrographic network, intensive overgrowth of small rivers, and irretrievable withdrawal of water resources growing with economic development. Since water exchange between groundwater and surface water bodies is dependent on their hydraulic connection, the response of groundwater level regime, its flow, and discharge into rivers to climate change and economic activities in the catchments varies. The water flow regulation system in this region was designed for a previous “quasi-stationary” climatic period. At present, with warming winters, the spring flood has significantly decreased. with its volume now almost equivalent to the regulating capacity of existing ponds. Therefore, the proportion of water retained in the upper links of the hydrographic network has increased, not only due to ponds but also because of the intensively overgrown beds of small rivers. As a result of these factors, coupled with the increasing irretrievable water resources withdrawal from the basin due to regional economic development and rising water consumption for greater crop yields across large areas, the groundwater drainage base in the rivers is being lowered. This has led to a continuous decrease in river levels since the early XXI century. In the future, this decline in groundwater levels may result in the degradation of the upper links of the hydrographic network, an increased risk of the aeration zone “drying up”, and a reduction of moisture content in the productive meter layer of soil with subsequent reduction of yields in the chernozem zone.