The spatio-temporal variability of individual storm waves in the coastal zone is studied. Wave chronograms were presented as sums of the first and second harmonics with amplitudes slowly varying in time, which are envelopes for the waves of the corresponding frequency bands. The amplitude-frequency structure of individual waves was estimated from the variations in the amplitude of the envelopes. Bi-spectral analysis was applied to estimate the phase composition of the waves. It is shown that, in the initial stage of transformation, the fluctuations of the waves of the first and second harmonics are synchronous. The amplitudes of the second harmonics are proportional to the squared amplitudes of the first harmonics. Thus, a simple model is possible for the description of individual waves based, for example, on the generalization of the Stokes theory. As the waves approach the coast, the ratio of the amplitudes of the first and second harmonics in individual waves varies in time chaotically, thus it is not possible to describe individual waves on the basis of a simple model. The main cause of the chaotic variation of the amplitudes is the backward transfer of energy from the highest harmonics to the first harmonics due to the sub-near resonant triad interaction close to the resonance. The phase composition of individual waves depends on the distance propagated by the waves and on the stage (main or backward) of the energy exchange between the nonlinear harmonics.

The study investigates cross-shore outer sand bar dynamics in an open-coast non-tidal beach at the Bulgarian Black Sea due to wave climate. On seasonal to short-term (1–2 years) time scale, monthly field measurements of the outer bar profiles were related to respective modeled nearshore wave data. Hereby, seaward-shoreward bar migration was examined depending on the wave forcing, wave non-linearity, wave transformation scenarios, storms and direction of wave incidence. Analysis revealed that intra-annually highly non-linear waves were responsible for outer bar displacement, while the direction of migration depended on wave period, duration of conditions with wave steepness >0.04, angle of approach and total duration of storms. Short-term bar evolution was mainly governed by wave height and storms’ parameters as the angle of approach and duration. The correlation between the outer bar location and wave height annual variations initiated the first for the explored Black Sea region examination of possible connection between wave height’s temporal fluctuations and the variability of climatic indices the North Atlantic Oscillation (NAO), the Atlantic Multi-decadal Oscillation (AMO), the East Atlantic Oscillation (EA), the Arctic Oscillation (AO), the East Atlantic-Western Russia (EA/WR) and the Scandinavian (SCAND) patterns. According to the results the inter-annual outer bar location may vary depending on periods of maximum annual wave fluctuations, which in turn predominantly depend on indices the EA (4–5, 10–11, 20–30 years), the EA/WR (2–4, 9–13 years) and the NAO (15 years).

This deliverable presents the generation of EUNIS habitat maps for Europe as a whole and for each of the pilot areas in REST-COAST. Subsequently, it presents the assignment of semi-quantitative scores for the contribution of each EUNIS (sub)habitat to the five key ecosystem services applying the rank scale 0 (none), 1 (very low contribution), 2 (low contribution), 3 (medium contribution), 4 (high contribution) to 5 (very high contribution). It also describes the assignment of the IUCN Red List of Habitats to each of the depicted EUNIS (sub)habitats in the pilot areas. And finally, to assess coastal system behaviour and restoration effects on ecosystem services and biodiversity gains under climate change, a homogenised score card methodology is presented to overcome the problem of comparing minor changes (some percents) with major changes (tens of percents) in the total scores for ESS or BDV in each pilot area.

Storms and related disasters are phenomena producing coastal hazards and endangering human life and occupation. The study evaluates coastal receptors’ exposure and their vulnerability to storm-induced flooding hazard along Varna regional coast in Western Black Sea, Bulgaria. The assessment is performed employing the Coastal Risk Assessment Framework (CRAF) developed within EU FP7 RISC-KIT project. It constitutes a screening process that allows determination of susceptible alongshore sectors (hotspots) by assessing relevant hazard intensities, hazard extents and potential receptors’ exposure vulnerability within them by means of coastal indices approach. The ultimate goal is to evaluate potential risk posed by flooding in support to coastal managers, decision and policy makers. Assessment of coastal receptors’ exposure vulnerability is done by exposure indicators approach, using hazard intensities and flooding extents relevant to return period of 100 years. The approach consists of combining several indicators into a single index, thereby allowing a rapid comparison of coastal sectors. Five types of receptors are considered to formulate the relevant exposure indicators: Land Use, Population, Transport, Utilities and Business, which subsequently are combined into an Overall Exposure Indicator to evaluate potential direct and indirect impacts. Results show that the most vulnerable to coastal flooding in terms of exposure are coastal sectors located within Varna Bay, comprising port and industry facilities with regional, national and international significance.