DOI: 10.5593/SGEM2016/B31/S12.072


Y.Fedorov, A. Ovsepyan , V.Savitskiy , A. Zimovets ,I Dotsenko
Wednesday 7 September 2016 by Libadmin2016

References: 16th International Multidisciplinary Scientific GeoConference SGEM 2016, www.sgem.org, SGEM2016 Conference Proceedings, ISBN 978-619-7105-61-2 / ISSN 1314-2704, June 28 - July 6, 2016, Book3 Vol. 1, 553-560 pp

Small rivers are among the most vulnerable components of the Earth ecosystems. Because of their size, shallow depth and low water circulation, they have a relatively low level of self-purification capacity, it is also true that they form the basis of the hydrographic network, considerably determines an originality of water composition and water biocenoses, forming of hydrological, biological and biochemical mode of middle and large rivers.
The article analyzes the results of field research of one of the small rivers of the Onega Bay of the White Sea.
River Kyanda is a tributary of Onega Bay of the White Sea. The uniqueness of this river is the availability of the wide strip of marshy land areas overgrown with reeds in the maritime coastal zone. These sites are separated from the riverbed by a sandy riparian shaft. At high tide the sea water percolates through sandy sediments and accumulates in them. During low tide, water accumulated in sandy sediments gradually infiltrates in river stock waters, thereby increasing their salinity. The article deals with the distribution of values of salinity, density, dissolved oxygen, pH and redox potential in the Onega Bay waterbody, the river Kyanda and its stream tributaries during the four phases of the water regime – high tide, low tide, arriving and decreasing water. In addition, the relationship between these parameters was analyzed.
The analysis of physical and chemical parameters of water allowed to identify the main consistent patterns and processes occurring in the mixing zone of the river, with the significant influence of tidal processes. Studies of salinity and marine origin salt content is established the influence of tidal events up until the closing target (village Kyanda). Dynamics of salinity and the proportion of sea salts in the composition of river waters are measured and described. It is significantly higher during the maximum high tide compared to the maximum outflow, it takes place approximately at a distance of 6 km from the marine edge of the delta. It is established that after the completion of this target there is a substantial reduction in the salinity value and the proportion of marine salts in river waters, as well as smoothing differences between the values of these indicators during high and low tides. Redox potential of water in river Kyanda is investigated: in July and August the river water was characterized by relatively low values of Eh and was generally undersaturated for oxygen content. This may indicate that the prevalence of organic matter degradation of its products. The discovered high salinity of Kyanda river waters during the decreasing water confirms the thesis, claiming an important role of the processes of return of sea water accumulated in floodplain sediments along with the river flow during the high tide. Such large-scale and comprehensive investigations are first-time-performed for the small rivers of the Onega Bay.

Keywords: small rivers, Onega Bay of the White Sea, physical and chemical characteristics of water, mixing zone, river Kyanda