Variability of the slope component of sediment balance for the erosion-channel system in anthropogenically transformed basin of a small river

The paper presents the study of spatiotemporal variability of surface sediment flow and the assessment of its influence on suspended sediment yield in the outlet section of a small river basin, i.e. the upper part of the Vorskla River (Belgorod Oblast), with an area of 1,85 thousand km². Time series of average annual suspended sediment yield from 1960 till 2021 were analyzed according to the data for the Kozinka – Vorskla gauging station (116 km from the river source). High heterogeneity of the sediment yield was found, during the period under review it decreased by 6,7 times (according to average values, from 0,27 to 0,04 kg/s). It was found that the   surface (basin) component predominates in the sediment balance, which is predominately soil matter eroded from the arable lands of the agriculturally developed catchment areas. The content of suspended sediment in river runoff has a greater response to changes in the intensity of snowmelt erosion than the rainfall one. However, a critical decrease in the snowmelt runoff layer caused by the climate changes of recent decades has led to   a decrease in the contribution of snowmelt erosion to annual soil losses. As a result, suspended sediment yield in the outlet section of the river has decreased. A quantitative assessment of rainfall erosion rates using the WaTEM/SEDEM model showed that the main source of sediment is plowed areas; annually 228,8 thousand tons   of soil matter are removed from the arable lands. At the same time, 76 thousand tons enter the river network, i. e. 66% of soil material mobilized by rainfall runoff accumulates within the catchment area. The dynamics of river flow regulation by ponds is considered. To date, sediment yield from 62% of the catchment area is intercepted by ponds. Over the past 40 years, the interception area of solid runoff has increased by 30%, and the volume of sediments entering the unregulated river network has decreased by 47%. The ponds and the upperlying gully network hold 61,4 thousand tons of sediments, which is 81% of the surface erosion in the basin. Thus, the climate-related decrease in snowmelt runoff from the catchment area, combined with the reduction of water yield during floods and the water management measures to regulate river flow by ponds, has resulted in a sharp reduction of suspended sediment discharge since the 1980-s and their further gradual decline.

1. Barabanov A.T., Petelko A.I. Faktory sklonovogo vesennego stoka na serykh lesnykh pochvakh v Tsentral’noi lesostepi [Factors of slope spring runoff on gray forest soils in the central forest-steppe], Vestn. Mosk. un-ta, Ser. 5, Geogr., 2023, vol. 78, no. 4, p. 18–27, DOI: 10.55959/10.55959/msu0579-9414.5.78.4.2. (In Russian)

2. Batista P.V., Laceby J.P., Davies J. et al. A framework for testing large-scale distributed soil erosion and sediment delivery models: Dealing with uncertainty in models and the observational data, Environmental Modelling & Soft ware, 2021, vol. 137, art. 104961, DOI: 10.1016/j.envs-oft.2021.104961.

3. Bezukhov D.A., Golosov V.N., Panin A.V. Otsenka koeffitsienta dostavki nanosov malykh vodosborov v lesostepnykh i stepnykh raionakh Vostochno-Evropeiskoi ravniny [Evaluation of the sediment delivery ratio of small watersheds in forest-steppe and steppe regions of the Russian plain], Izv. Rossiiskoi akademii nauk, Ser. geograficheskaya, 2019, no. 4, p. 73–84, DOI: 10.31857/S2587-55662019473-84. (In Russian)

4. Buryak Z.A., Narozhnyaya A.G., Gusarov A.V., Beylich A.A. Solutions for the spatial organization of cropland with increased erosion risk at the regional level: A case study of Belgorod Oblast, European Russia, Land, 2022, vol. 11, no. 9, art. 1492, DOI: 10.3390/land11091492.

5. Chizhikova N., Yermolaev O., Golosov V. et al. Changes in the regime of erosive precipitation on the European Part of Russia for the period 1966–2020, Geosciences, 2022, vol. 12, art. 279, DOI: 10.3390/geosciences12070279.

6. Erozionno-ruslovye sistemy [Fluvial systems], R.S. Chalov, A.Yu. Sidorchuk, V.N. Golosov (еds.), Moscow, INFRA-M Publ., 2017, 697 p. (In Russian)

7. Fomicheva D.V., Zhidkin A.P., Komissarov M.A. Multiscale estimates of soil erodibility variation under conditions of high soil cover heterogeneity in the northern forest-steppe of the Central Russian Upland, Eurasian Soil Sci ence, 2024, vol. 57, no. 2, p. 325–336, DOI: 10.1134/S1064229323602895.

8. Golosov V.N., Zhidkin A.P., Petelko A.I. et al. Field verification of erosion models based on the studies of a small catchment in the Vorobzha River Basin (Kursk oblast, Russia), Eurasian Soil Science, 2022, vol. 55, no. 10, p. 1508–1523, DOI: 10.1134/s1064229322100040.

9. Gusarov A.V., Sharifullin A.G. Sovremennaya eroziya i stok vzveshennykh nanosov na stepnom yugo-vostoke Russkoi ravniny (bassein r. Samara) [Contemporary erosion and suspended sediment yield within river basins in the steppe of the southeastern part of the Russian Plain: A case study of the Samara River basin], Izv. Rossiiskoi akademii nauk, Ser. geograficheskaya, 2019, no. 1, p. 37– 51, DOI: 10.31857/S2587-55662019137-51. (In Russian)

10. Ivanov V.A., Chalov S.R. Otsenka balansa nanosov rek Ob’ i Enisei [Sediment budget assessment of the Ob and the Yenisei rivers], Geomorfologiya, 2021, vol. 52, no. 3, p. 79– 89, DOI: 10.31857/S0435428121030056. (In Russian)

11. Kanatieva N.P., Krasnov S.F., Litvin L.F. [Recent changes of climate factors of erosion in Northern Povolzie], Eroziya pochv i ruslovye protsessy [Soil Erosion and Channel Processes], R.S. Chalov (еd.), Moscow, MSU Publ., 2010, vol. 17, p. 14–27. (In Russian)

12. Kornilova E.A., Lisetskii F.N., Rodionova M.E. Gidroekologicheskie osobennosti reki Vorskly (rossiiskii uchastok) v kontekste prirodno-khozyaistvennykh izmenenii [Hydroecological features of the Vorskla River (Russian section) in the context of natural and economic changes], Regional’nye geosistemy, 2023, vol. 47, no. 4, p. 550–568, DOI: 10.52575/2712-7443-2023-47-4-550-568. (In Russian)

13. Kozlov D.N., Zhidkin A.P., Lozbenev N.I. Tsifrovoe kartografirovanie erozionnykh struktur pochvennogo pokrova na osnove imitatsionnoi modeli smyva (severnaya lesostep’ Srednerusskoi vozvyshennosti) [Digital mapping of soil cover eroded patterns on the bassis of soil erosion simulation model (northern forest-steppe of the Central Russian Upland)], Byulleten’ Pochvennogo instituta imeni V.V. Dokuchaeva, 2019, vol. 100, p. 5–35, DOI: 10.19047/0136-1694-2019-100-5-35. (In Russian)

14. Kumani M.V., Shulgina D.V., Kiselev V.V. Mnogoletnyaya dinamika osnovnykh elementov stoka rek v predelakh Tsentral’nogo Chernozem’ya [Long-term dynamics of the main elements of river flow within the Central Chernozem region], Regional’nye geosistemy, 2021, vol. 45, no. 4, p. 617–631, DOI: 10.52575/2712-7443-2021-45-4-617-631. (In Russian)

15. Lebedeva M.G., Lupo A.R., Chendev Y.G. et al. Changes in the atmospheric circulation conditions and regional climatic characteristics in two remote regions since the mid-20th century, Atmosphere, 2019, vol. 10, no. 1, art. 11, DOI: 10.3390/atmos10010011.

16. Lisetskii F. Water resources of rivers and erosion-accumulation processes, Biosc. Biotech. Res. Comm., 2022, vol. 15, no. 4, p. 1–3, DOI: 10.21786/bbrc/15.4.1.

17. Lisetskii F.N., Buryak Zh.A., Marinina O.A. Geomorfologicheskaya asimmetriya raznoporyadkovykh rechnykh basseinov (na primere Belgorodskoi oblasti) [Geomorphological asymmetry of river basins belonging to different orders (based on the Belgorod region)], Uchenye Zapiski Kazanskogo Universiteta, Seriya Estestvennye Nauki, 2018, vol. 160, no. 3, p. 500–513. (In Russian)

18. Maltsev K., Yermolaev O. Assessment of soil loss by water erosion in small river basins in Russia, Catena, 2020, vol. 195, art. 104726, DOI: 10.1016/j.catena.2020.104726.

19. McCool D.K., Foster G.R., Mutchler C.K. et al. Revised slope length factor for the universal soil loss equation, Transactions of the ASAE, 1989, vol. 32, no. 5, p. 1571– 1576, DOI: 10.13031/2013.31192.

20. Moszherin V.V. [Division of suspended sediment runoff from rivers of Northern Eurasia into channel and basin components and its geomorphological interpretation], Regional’nye issledovaniya prirodno-territorial’nykh kompleksov [Regional studies of natural-territorial complexes], V.V. Sirotkin, R.R. Denmukhametov (еds.), Kazan, Med-doc Pybl., 2012, p. 93–100. (In Russian)

21. Rompay van A., Verstraeten G., Oost van K. et al. Modelling mean annual sediment yield using a distributed approach, Earth Surface Processes and Landforms, 2001, vol. 26, no. 11, p. 1221–1236, DOI: 10.1002/esp.275.

22. Yermolaev O.P., Mukharamova S.S., Maltsev K.A. et al. Geography and geoecology of Russia in the mosaic of river basins, Geography and Natural Resources, 2023, vol. 44, no. 3, p. 208–214, DOI: 10.1134/S1875372823030046.

23. Zhidkin A., Gennadiev A., Fomicheva D. et al. Soil erosion models verification in a small catchment for different time windows with changing cropland boundary, Geo derma, 2023, vol. 430, art. 116322, DOI: 10.1016/j.geoderma.2022.116322.

24. Web sources

25. Bulygina O.N., Veselov V.M., Razuvayev V.N. et al. Opisaniye massiva srochnykh dannykh ob osnovnykh meteoro logicheskikh parametrakh na stantsiyakh Rossii [Description of the array of urgent data on the main meteorological parameters at stations in Russia], URL: http://meteo.ru/data/basic-parameters/ (access date 03.02.2025).

26. Rechnyye basseyny Yevropeyskoy Rossii [River basins of European Russia], URL: https://bassapr.kpfu.ru/map-bender/application/bassepr (access date 03.02.2025).