Coastal Processes in the Russian Baltic (Eastern Gulf of Finland and Kaliningrad Area)
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Downloaded from http://qjegh.lyellcollection.org/ by guest on October 8, 2021 Research article Quarterly Journal of Engineering Geology and Hydrogeology https://doi.org/10.1144/qjegh2020-036 | Vol. 54 | 2020 | qjegh2020-036 Coastal processes in the Russian Baltic (eastern Gulf of Finland and Kaliningrad area) Daria Ryabchuk1*, Alexander Sergeev1, Evgeny Burnashev2, Viktor Khorikov1, Igor Neevin1, Olga Kovaleva1, Leonid Budanov1, Vladimir Zhamoida1 and Aleksandr Danchenkov3,4 1 A.P. Karpinsky Russian Geological Research Institute, 74 Sredny pr., St Petersburg 199106, Russia 2 State Budgetary Institution of Kaliningrad Region “Baltberegozaschita”, Khutorskaya st. 1, Svetlogorsk 238560, Russia 3 Shirshov Institute of Oceanology, Russian Academy of Sciences, 36 Nahimovskiy prospekt, Moscow 117997, Russia 4 I. Kant Baltic Federal University, 14 Nevskogo A. str., Kaliningrad 236016, Russia DR, 0000-0003-2266-8688; AD, 0000-0002-1710-3757; AD, 0000-0002-1710-3757 * Correspondence: [email protected] Abstract: The results of both onshore and offshore monitoring of the coastal zone in the Russian Baltic reveal the high intensity and recent acceleration of coastal dynamics caused by an increasing frequency of extreme hydrodynamic events and anthropogenic impacts on the diverse geology. Stable coasts dominate in the eastern Gulf of Finland, but the local rate of shoreline recession is up to 2.0 m a−1, reaching 5 m in one extreme storm event. The coastal zone of the Kaliningrad area is diverse. The western coast of the Sambia Peninsula is controlled by anthropogenic influences linked to the exploitation of geological resources. The beaches advance when the supply of artificial sediments from opencast amber mines increases, whereas the shoreline retreat reaches 10–20 m a−1 when the input is interrupted. Active landslides and beach degradation dominate along the northern coast of the Sambia Peninsula. Large areas of pre-Quaternary deposits, outcrops and boulders in the nearshore provide evidence of sediment deficiency offshore. The coastal geological hazards are dependent on climate. A comprehensive understanding of the main trends in climate change is important for predicting and mitigating future damage to the coastal infrastructure and for selecting adaptation strategies. Thematic collection: This article is part of the Mapping the Geology and Topography of the European Seas (EMODnet) collection available at: https://www.lyellcollection.org/cc/EMODnet Received 11 February 2020; revised 18 May 2020; accepted 2 July 2020 The Baltic Sea is an intra-European, transboundary water basin. The Baltic, to +10 mm a−1 at the top of the Gulf of Bothnia (Harff et al. surrounding regions are densely populated and the drainage area is 2017). The impact of waves on the coastal zone of the Baltic Sea highly developed economically (Fig. 1b). Geological mapping of differs significantly depending on the geographical position, the floor of the Baltic Sea is one of the most interesting and shoreline configuration and wave fetch. challenging tasks in the EMODnet-geology project because the The coastal zone of the Russian Baltic consists of two distinct seamless maps are compiled by ten partner institutions from nine areas: the easternmost part of the Gulf of Finland and the SE Baltic countries, each with a long history of different mapping approaches within the Kaliningrad area (Fig. 1b). The southern coast of the and classification techniques. From the perspective of the Russian Gulf of Finland experiences similar processes to the EMODnet-geology Work Package 4 (Coastal Behaviour), the adjoining Estonian shores, whereas the skerries of the NW resemble most remarkable feature of the Baltic Sea is its great variety of much of the Finnish coast of the Gulf. The coasts in the Kaliningrad coastal types. These are a result of differences in the geological area consist of the high cliffs of the Sambia Peninsula and two structure of the various regions of the Baltic area and the diversity of significant sediment accretion bodies: the Vistula Spit, shared with land movement, with sinking southwestern and uplifting north- Poland to the SW, and the Curonian Spit, the northeastern half of eastern coastal areas (Harff et al. 2011). The main geological which lies in Lithuania. Both segments of the Russian Baltic are features of the Baltic Basin are controlled by its position between characterized by intense coastal erosion, with a wide spectrum of the Fennoscandian crystalline shield, represented by Precambrian landslides evident on the coastal cliffs of the Sambia Peninsula. magmatic and metamorphic rocks, and the East European Platform, The coastal areas and beaches of the two parts of the Russian characterized by Phanerozoic sedimentary cover, the thickness of Baltic are highly valuable from the perspective of both recreation which increases by up to several kilometres from NE to SW (Šliaupa and nature protection and are under great pressure from anthropo- and Hoth 2011). The hard metamorphic and magmatic rocks of the genic activity. The urgent need for an effective coastal protection Scandanavian Shield outcrop along the northern coasts of the Gulf strategy is recognized by the local authorities and is in the early of Finland, the Gulf of Bothnia and the western Baltic Proper. stages of development. Such a strategy needs to be based on a clear Quaternary deposits are widespread along the southern Baltic scientific understanding of natural coastal processes, taking into coasts, but, in the areas where these are eroded, the coastal cliffs are consideration both marine and geological factors and identifying the composed of relatively easily erodible Ordovician and Devonian (in main trends in the current and future evolution of the shoreline. Estonia) and Paleogene–Neogene (in the SE Baltic, including the Our work aimed to identify the main trends in the evolution of the Kaliningrad area) sedimentary rocks. The rates of glacio-isostatic coastline and to calculate the rates of shoreline retreat or advance, rebound along the Baltic coast vary from −1.5 mm a−1 in the SE mapping the coastal geology and identifying hotspots of coastal © 2020 The Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License (http://creativecommons.org/ licenses/by/4.0/). Published by The Geological Society of London. Publishing disclaimer: www.geolsoc.org.uk/pub_ethics Downloaded from http://qjegh.lyellcollection.org/ by guest on October 8, 2021 2 D. Ryabchuk et al. Fig. 1. (a) Morphogenetic classification and coastal dynamics of the Eastern Gulf of Finland. The measuring points are points of retrospective analyses of coastal escarpments and beach positions based on remote sensing data (rates in units of ma−1); relict uplifted Holocene marine terraces are terraces formed during the maximum of Holocene transgressions (Lake Ancylus and the Littorina Sea) and are mostly covered by sand; coastal types are morphogenetic coastal types (see Table 1). (b) Location map of the study area. FPF, St Petersburg Flood Protection Facility. erosion. Our aim was to link the occurrence of different lithologies dynamics of the Kaliningrad Region have been continued since with different coastal behaviours, revealing the natural and 1972 by the Agency of Coastal Engineering, later reorganized as the anthropogenic driving forces of coastline dynamics, and to Bureau Baltberegozashita (Boldyrev et al. 1990; Ryabkova 2000; propose a strategy for coastal management and protection. Boldyrev and Ryabkova 2001). There is a long history of previous research in this region, with the Hydrological studies carried out by the ABIO RAS from 1980 to first scientific investigation of the geology and coastal processes of the late 1990s classified the near-bottom currents from the shoreline the SE Baltic published at the beginning of the twentieth century. to the outer boundary of the coastal zone and determined the Abromeit et al. (1900) described the geomorphological features of existence of sediment transport towards the east (Babakov 2002). the coastal zone and the problem of dune stability. Tornquist (1914) The most recent overview of the coastal geology was presented by considered the problems of sediment drift and the impact of storms Zhindarev et al. (2012). on the Curonian Spit. Based on field observations during the winter The Laboratory of Coastal Systems of ABIO RAS has conducted storm of 9–10 January 1914, he showed that the coastal system may coastal monitoring studies along the shores of the Kaliningrad area lose twice as much material during a single extreme storm event as it since the year 2000. Numerous annual cross-shore profiles have accumulates over a whole year. Data on the geological structure of been measured using permanent concrete benchmarks as fixed the Quaternary deposits and erratic blocks of Cretaceous rocks near points to calculate the rates of coastal erosion (Bobykina and the Curonian Spit were published in 1919 (Wichdorff 1919). Boldyrev 2008). The coastal zone and nearshore bottom dynamics The first map of the Quaternary deposits of the Kaliningrad of the Curonian Spit were analysed by Zhamoida et al. (2009). Region was compiled by Vereisky in 1946 (Vereisky 1946). The geology and geomorphology of the Eastern Gulf of Finland Complex hydrogeological investigations between 1958 and 1967 (EGoF) coasts have been studied since the 1920s (Yakovlev 1925; enabled the development of onshore geological, hydrogeological Markov 1931). Coastal