Климатические и не климатические факторы формирования стока в бассейне реки Битюг

As a result of the study, the peculiarities of trends in changing the characteristics of the regional water balance have been revealed on the example of the Bityug River basin, which is a large tributary of the Don River. Significant changes have occurred in the inflow and outflow components of the water balance, as well as in the ratio of surface and groundwater in the territory under consideration.

The amount of effective precipitation causing surface runoff decreased by ~18 % and the annual runoff layer of the Bityug River by 10−20 mm. The total runoff layer of the spring flood of the Bityug River decreased by an average of 1.6 times. The effect of increasing winter runoff due to the increase in the melt component and winter liquid precipitation, improvement of groundwater supply in winter as a result of increased infiltration capacity of soils reached its limit by 2007, caused by prolonged low-water periods, after which there is a decrease in river and groundwater levels.

The duration of the period between the minimum fall-winter and minimum pre-spring water levels and the period of highest groundwater recharge decreased by 29−30 days on average, indicating accelerated depletion of groundwater storage during the off-season period of the year due to decreased recharge.

Significant intra-seasonal changes in the regime of snow accumulation and snowmelt have occurred. The duration of the locking layer has decreased 2−3 times since the 1990s. According to observations at the Kamennaya Steppe water balance station, the moisture content of the upper meter layer has decreased by 35−40 mm on average in the last decade. The main reasons for the observed changes are intra-annual redistribution of precipitation and increase in air temperature, as a result of which the duration of the period of evaporation from the soil surface has increased.

Since 1981, the annual groundwater supply of the Bityug River has become comparable to the maximum runoff and even exceeds it in some years after 2007. The contribution of annual groundwater supply of rivers to the annual runoff has increased since 1980 by 1.7−2 times. 

Intensive anthropogenic load of different nature on surface and water bodies prevents their restoration after water deficit periods.