Makhinov A. N., Makhinova A. F.

Influence of high floods on the dynamics in floodplain islands of the Amur River P. 158 -168.

UDC 556.166:551.435.122(282.257.5)

DOI 10.37724/RSU.2023.80.3.016

 

Abstract. It is well-known fact that the floodplain of the Amur River in the lower reaches is represented mainly by insular floodplain massifs of various morphology and sizes. The largest islands in their marginal parts are transformed as a result of erosion of the banks and appearance of new, rapidly overgrowing spits and side bars. Small islands in the channel are teardrop-shaped and migrate down the river. The research provides data on the depth and duration of flooding of floodplain massifs in various parts of the lower reaches of the Amur River. It has been established that during the largest floods, the flooding of the main part of the plain surface lasts 50–70 days, with water depth of 3–4 m. The main varieties of accumulative formations are high near-channel swells (10–15 m wide) and sandy plumes in the coastal parts of the floodplain (up to 60 m wide and hundreds of meters long along the river basin). Morphological and morphometric characteristics are given, as well as features of their formation in various parts of floodplain massifs. It is shown that during high floods, uneven sedimentation occurs on the floodplain, which has various effects on the transformation of the relief and the composition of floodplain deposits. It was shown that erosion activity on the surface of the floodplain, even in areas of deep linear hollows, does not manifest itself due to the extremely dense topsoil, held together by the roots of perennial highly productive grasses. However, significant areas of floodplain banks of the river are subject to intense erosion. The average and maximum speed of coast erosion was determined.

 

Keywords: Amur, floodplain, large floods, floodplain flooding, floodplain sedimentation.

 

Bibliography 

 

  1. Golubtsov G. B., Chalov R. S. Comparative hydrological and morphological analysis of the islands of complexly branched channels of the upper Ob and middle Lena. Vestnik Udmurtskogo universiteta. Ser. “Biologiya. Nauki o Zemle” [Bulletin of the Udmurt University. Series “Biology. Earth Sciences”]. 2020, vol. 30, iss. 2, pp. 164–174. (In Russian).
  2. Danilov-Danilyan V. I., Gelfan A. N. Extraordinary flooding in the Amur river basin. Vestnik Rossiyskoy akademii nauk [Bulletin of the Russian Academy of Sciences]. 2014, vol. 84, iss. 9, pp. 817–825.
    (In Russian).
  3. Kim V. I., Shamov V. V. Characteristics of solid runoff in the middle  reaches of the River Amur. Geokhimicheskiye i ekologo-biogeokhimicheskiye issledovaniya v Priamurye: sb. st. [Geochemical and ecological-biogeochemical studies in the Amur region: collection of articles]. Vladivostok, Dalnauka Publ., 2000, iss. 10, pp. 186–191. (In Russian).
  4. Makhinov A. N., Pozdnyakov A. V., Ushakov A. V. Mechanism of the formation of mobile islands in riverbeds (on the example of the Amur River). Geografiya i prirodnye resursy [Geography and Natural Resources]. 1986, iss. 4, pp. 25–30. (In Russian).
  5. Makhinov A. N., Chalov R. S., Chernov A. V. Directed sediment accumulation and channel morphology of the Lower Amur. Geomorfologiya [Geomorphology]. 1994, iss. 4, pp. 70–78. [In Russian].
  6. Makhinov A. N.  Sovremennoye relyefoobrazovaniye v usloviyakh allyuvialnoy akkumulyatsii [Modern relief formation under conditions of alluvial accumulation]. Vladivostok, Dalnauka Publ., 2006, 232 p. (In Russian).
  7. Makhinov A. N. Eolian landforms in the floodplain of the Amur River. Geomorfologiya [Geomorphology]. 2017, iss. 2, pp. 52–62. (In Russian).
  8. Chalov R. S. Complexly branched channels of lowland rivers: conditions of their formation, morphology and deformations. Vodnyye resursy [Water resources]. 2001, vol. 28, iss. 2, pp. 166–171. (In Russian).
  9. Chalov R. S. Ruslovedeniye: teoriya, geografiya, praktika [Studies of river channels: theory, geography, practice]. Moscow, USSR Publ., 2008-. Vol. 1: Channel processes: factors, mechanisms, forms of manifestation and conditions for the formation of river channels. 2008, 608 p.; vol. 2: Morphodynamics of river beds. 2011, 960 p. (In Russian).
  1. Egozi R., Ashmore P. Experimental analysis of braided channel pattern response to increased discharge. Geophysical Research Earth Surface. 2009, pp. 941–962.
  2. Large Rivers. Geomorphology and Management. Ed. by Avijit Gupta. Singapore, John Wiley & Sons, 2008, 689 p.
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