The Black Sea basin is a unique and very complex environment in the World Ocean as a result of its evolution, location and history. This is the reason why in the last years there is an increasing scientific interest in deciphering the processes and mechanisms governing this area. Besides the well-known environmental problems of the basin related to pollution, eutrophication, overfishing and loss of biodiversity, erosion (as a result of storminess, sea level rise and human interventions) is affecting many coasts around the Black Sea.This paper deals with an evaluation of the erosion hazards along the Black Sea coasts, (through an in-depth and well-grounded scientific analysis of a comprehensive database of multiple sources), together with the discussion of erosion management issues at basin scale (through literature review and risk perceptions analysis related to planning strategies, protection measures, legislation and administrative implementation). For this endeavour, we have computed a Coastal Sensitivity Index (CSI) at 1-km spatial scale for more than 4000 sectors around the Black Sea, taking into consideration geological-geomorphological and physical characteristics of each sector through the following parameters: type of coast (coastal geomorphology and lithology), coastal slope (from shoreline to 20 m depth), shoreline changes in the last 33 years, wave incidence (the angle between the shoreline and the dominant storm waves), significant wave height during storm conditions and relative sea level rise. The results for each parameter are detailed and statistically presented and are finally aggregated into CSI. Results showed circa 19% (800 km) of the Black Sea coasts are undergoing serious erosion, affecting mostly the coastlines of Romania (37%), Ukraine (29%) and Georgia (26%). The most sensitive sectors to erosion are superposed on the areas with relatively high storm waves and incidence angles: the deltaic coastlines of the main deltas (Danube, Kizilirmak, Yesilirmak, Sakarya, Rioni, Enguri, Kodori, Chorokhi) of the Black Sea, the low-lying areas along the lagoons, limans, coastal barriers and spits from Kalamitsky, Odessa and Karkinitsky Bays (Dniester, Tendrovskaya and Dzharlygachskiy areas), Chornomorske - Yevpatoriya area (in Crimea), Taman - Anapa (in Russia) and Karasu - Karaburun (in Turkey) and the rocky areas Gelendzhik - Tuapse (in Russia), Sevastopol - Cape Meganom (in Crimea) and Inebolu - Eregli (in Turkey). These highly sensitive sectors cover extensive areas along the coastlines of Russia (57%), Georgia (46%), Turkey (44%), Romania (43%) and Ukraine (35%).Implications of coastal erosion management in the Black Sea riverine countries (with different coastal legislation, EU/non-EU regulations and directives etc.) are discussed, emphasizing the main problems and shortcomings. Some guidelines for coastal erosion management in the specific case of the Black Sea are listed at the end of the paper. Despite the complicated regional geo-political context, common framework of coastal erosion management for the entire Black Sea basin is needed at all levels (political, administrative, academics and research) through cross-border cooperation related to legislation, regulations (integrated approaches for Marine Spatial Planning and Coastal Zone Management), research and academic programs, coastal zone monitoring, management/planning (prioritization of protection works and promotion of soft engineering measures) and public participation.

A model of an artificial beach is proposed for protecting a seacoast subjected to erosion under significant storm surge impact. The beach profile properties are based on the Dean equilibrium profile. It is shown that coarser sand yields a greater total beach width, but requires a greater volume of berm material. At the same time, this results in decreased loss of material to longshore sediment transport. The results of applying the model to three sectors of eroded coast in the Kurortny District of St. Petersburg (eastern Gulf of Finland) recommend the use of medium-grained 0.3-0.5 mm sand to construct the artificial beach. In this case, the width of the dry beach section would be about 80-140 m, while the volume of berm material would be (1.3-3.2) x 10(2) m(3) per one meter of coast length depending on the sediment deficit for a given coastal sector. To minimize the relative loss of material, it is suggested to construct a beach no less than 1 km in length; in this case, more than half the initial beach volume would be retained even after 30 years. Modeling of extreme storm impact leads to the conclusion that the designed beach profiles are only slightly deformed and can retain their resources for many years.

It is shown that behavior of a multiple-bar system during a storm can be described with a model assuming that bars move toward the sea at almost the same mean rate, while the depths over the bars increase in accordance with the local bed slope. Analysis of the suspended-sediment balance over the bar crest yields an expression for the bar movement rate, which demonstrates a very strong dependence on the ratio of wave height to depth above the bar crest. When the empirical criterion of bar activity [11] is used, the proposed model can assess bar displacement during storm impact and predict the poststorm bed profile. Comparison with published field data leads to the conclusion that the computed and observed storm-induced deformations of barred beach slopes are satisfactorily consistent.

A model is developed for predicting the sand shore profile formed by storm event impact. The model takes into account the cumulative effect of elementary processes responsible for changes in the nearshore relief and relies on both the law of conservation of mass and the adopted geometrical scheme for the coastal profile. The latter is approximated by analytical curves, the properties of which are related to the acting wave parameters. The morphological consequences of a given storm are determined by the concept of effective wave height taking into account the temporal structure of the storm cycle and, in particular, the relative duration of the storm decay phase. The model is verified by published observation data obtained for the US Atlantic and Pacific coasts.

An analysis of the variability of wave climate and energy within the Black Sea for the period 1960-2011 was made using field data from the Voluntary Observing Ship Program. Methods using wavelet analysis were applied. It was determined that the power flux of wave energy in the Black Sea fluctuates: the highest value is 4.2 kW/m, the lowest is 1.4 kW/m. Results indicate significant correlations among the fluctuations of the average annual wave heights, periods, the power flux of wave energy, and teleconnection patterns of the North Atlantic Oscillation (NAO), the Atlantic Multi-decadal Oscillation (AMO), the Pacific Decadal Oscillation (PDO) and the East Atlantic/West Russia (EA/WR). It was revealed that, in positive phases of long-term periods of AMO (50-60 years) as well as PDO, NAO, and AO (40 years), a decrease of wave energy was observed; however, an increase in wave energy was observed in the positive phase of a 15-year period of NAO and AO. The positive phase of changes of EA/WR for periods 50-60, 20-25, and 13 years led to an increase of wave energy. The approximation functions of the oscillations of the average annual wave heights, periods, and the power flux of wave energy for the Black Sea are proposed.

Storminess variability is of key importance for many marine applications, naval and coastal engineering. Studying the evolution of this phenomenon along with large-scale atmospheric connections patterns and ability to predict them is crucial in the context of problem of global climate change. Based on field data and numerical simulations correlation of storminess with teleconnection patterns in different regions of the Black Sea was studied. It was shown that numerical simulations could be used for climate variability analysis if processed properly.

Analysis of the dynamics of coastal relief during long time scales allows us to define differences and general trends in the evolution of different coastal types. Long-term dynamics of various coastal profiles was explored on the basis of cartographic data and individual field measurements for different types of sandy beaches located in the northern and northwestern coasts of the Black Sea. The variability observed in the coastal underwater profile dynamics can be associated with various factors as: long-term variability of sediment budgets, bed dynamics due to storm intensity and relative sea level changes as a result of tectonic conditions. The results suggest a relative stability of the outer border of the dynamic zone defined by wave regime during the analyzed period. © 2017 IEEE.