STRUCTURAL AND MORPHOMETRIC ANALYSIS OF THE 3RD ORDER RIVER BASINS OF THE ILIMPEYA-NIDYM HIGH TRAP PLATEAU (KRASNOYARSK KRAI)
T.N. Geis1,2, M.Yu. Opekunova3, A.V. Bardash3, A.S. Prokushkin2
1Institute of Space and Information Technologies, Siberian Federal University, Krasnoyarsk, Russia
2V.N. Sukachev Institute of Forest, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, Russia
3V.B. Sochava Institute of Geography, Siberian Branch, Russian Academy of Sciences, Irkutsk, Russia
Keywords: Central Siberian Plateau, river basins, Strahler stream order, structural and morphometric indices, type of basin functioning, geoinformation systems
Abstract
The structural and morphometric analysis of small rivers of the middle reaches of the Nizhnyaya Tunguska River, draining the Ilimpeya-Nidym high trap plateau located within the Central Siberian Plateau, was carried out using nine drainage basins as an example. To determine the morphometric characteristics of the streams we used scenes from the global digital elevation model FABDEM ver. 1-2. The standard method of processing a digital elevation model in ArcGIS Desktop 10.1 was applied as an algorithm for constructing hydrological networks, based on the morphometric analysis of river basins (Horton analysis, implemented in the A. Strahler’s stream coding system). Using the simplest structure of the basin organization of the Ganalchik River as an example, the article considers in detail the erosion network of streams of the 3rd order subbasins, which is characterized by significant variability of the main structural and morphometric indicators. For the study area, in general, a wide variation in the values of structural indices and morphometric characteristics was revealed. The observed deviations of the structural basin indices from the modal values reflect the regional specifics of the geological and geomophrological structure of the territory and result from the layering of relief characteristic of the Ilimpeya-Nidym trap plateau, high tectonic fragmentation at elevations of 600-800 m, and the presence of traces of mountain-valley glaciation. In particular, it was found that the rivers under study have weak dissection of the river network in the middle and upper reaches, and the study area is dominated by basins with uneven distribution of sediments along the main channel due to the middle and lower reaches with the most stable proportion of the 3rd order channels. The predominant basins among all 3rd order basins of the studied rivers are those with such types of functioning as transit basins with a tendency to accumulation and storage basins, which account for 37 and 29 %, respectively.
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