Contemporary Trends in River Flow, Suspended Sediment Load, and Soil/Gully Erosion in the South of the Boreal Forest Zone of European Russia: The Vyatka River Basin

Abstract

Recent decades in the north of the East European Plain have been characterized by significant changes in climate and land use/cover, especially after the collapse of the USSR in 1991. At the same time, the hydrological consequences of these changes, especially changes in erosion processes and river sediment load, have been studied insufficiently. This paper partially covers this existing knowledge gap using the example of the Vyatka River basin. Draining an area of 129,000 km2, the Vyatka River is among the largest rivers in the boreal forest zone of European Russia. Cultivated land occupies about one-fifth of the river basin area; about three-fourths is covered by taiga forest vegetation. The results of state long-term hydrometeorological monitoring and information on land use/cover made it possible to reveal contemporary (since the 1960s) hydrological and erosion-intensity trends and their drivers within the greater (96%) part of the river basin. There has been a statistically insignificant increase in water discharge in the Vyatka River basin during recent decades. This is due to a statistically insignificant increase (for the entire basin studied) in the spring snowmelt-induced floodwater flow and a statistically significant rise in the discharge in the year’s warm and cold seasons. The main reason for the detected trends is increased precipitation, including heavy rainfall during the warm season. In contrast to this, the total annual suspended sediment load of the river (especially that which was snowmelt-induced) and, consequently, soil/gully erosion intensity have experienced a significant decrease in recent decades (up to 58% between 1960–1980 and 2010–2018). Land-use/-cover changes (a reduction of cultivated land area and agricultural machinery, a decline of livestock in pastures) following the collapse of the Soviet Union are considered the main reasons for this decrease. The most noticeable changes in water discharge, suspended sediment load, and erosion intensity were observed in the most agriculturally developed southwest and south parts of the Vyatka River basin. All the above trends may be considered with a high probability to be representative for the south sector of the taiga zone of the East European Plain.

Denudation and geomorphic change in the Anthropocene; a global overview.

“…In the basin of the Vyatka River, one of the largest rivers in the boreal forest zone of the East European Plain (Russia), the river's suspended sediment load has decreased by almost 40% over the past 60 years due to a nearly 47% reduction in the area of cultivated land in its basin (Gusarov et al, 2021). Based on field, hydrological and modelled data, it was concluded that a reduction in surface runoff during the snowmelt period, an increase in the proportion of arable land under perennial grasses, and a decrease in the area of cultivated land, are key factors in reducing soil loss in river basins within the forest, forest steppe and steppe zones of the East European Plain (Mal'tsev et al, 2019;Gusarov, 2019).…”

Prediction of the Amount of Sediment Deposition in Tarbela Reservoir Using Machine Learning Approaches

“…The recent decades in the north of the East European Plain have been characterized by Gusarov et al [22] with notable shifts in climate and land cover in the Vyatka River basin. Török et al [23] used the most popular empirical model's application range.…”

Runoff of Water and Its Quality under the Combined Impact of Agricultural Activities and Urban Development in a Small River Basin

“…This was due to increased economic activity within the watersheds, as well as significant climate change. During two or three centuries of the intensive development of watersheds for agricultural needs, the rivers have become heavily silted, although, after the collapse of the USSR in 1991, a significant decrease in the intensity of erosion and river runoff of suspended sediments was noted in the forest steppe zone of European Russia [62]. Under the conditions of the active intensification of soil erosion in watersheds, the main part of the floodplain-although it is regularly flooded with water and grows due to the vertical accumulation of sediments-is nevertheless not eroded and is not renewed by a concentrated channel flow of water.…”