New Storm Breaches in the Context of Non-Tidal Inlet Dynamics: Storm Bettina (2023), Black Sea Coast, Ukraine

Davydov, O.V., Buynevich, I.V., and Shvets, O.M., 2024. New storm breaches in the context of non-tidal inlet dynamics: Storm Bettina (2023), Black Sea coast, Ukraine. In: Phillips, M.R.; Al-Naemi, S., and Duarte, C.M. (eds.), Coastlines under Global Change: Proceedings from the International Coastal Symposium (ICS) 2024 (Doha, Qatar). Journal of Coastal Research, Special Issue No. 113, pp. 1031–1035. Charlotte (North Carolina), ISSN 0749-0208. Non-tidal breaches and inlets remain relatively unstudied coastal landforms. Along the northern coast of the Black Sea, Ukraine, an intense storm resulted in record breaching along the Tendra-Dzharylgach Barrier (TDB) complex, which has been the subject of recent research due to its unique inlet (prorva) morphodynamics and evolution. The periodicity of prorva formation corresponds to the frequency of intense storms, with breaching phases recurring at ∼40-year intervals. Their overall function and longevity depend on a combination of hydrodynamic forcings and morphosedimentary responses, some similar to their microtidal (wave-dominated) counterparts. The lifespan of individual breaches ranges from days to decades, with more stable inlets exhibiting many general morphological elements of their tidal equivalents, in this case a channel terminating in two surge deltas. Historic and cartographic databases have been integrated with >25 years of field research, however due to recent military occupation of the TDB in 2022, remotely sensed data emerged as a primary means of analyzing recent trends (inlet closure) and the new breaching phase. In November 2023, storm surge from a cyclonic system, locally named Storm Bettina, raised the seaside water level by 1.1-1.3 m and generated 3.3-3.7-m-high waves (max: > 9 m), while the bayside experienced a lowering of 0.3-0.5 m. This resulted in extensive overwash and breaching of narrow central barrier segments (average elevation ∼1.0 m) updrift from recurved distal ends. Prior to the storm, two prorvas were active, both along Tendra Spit. Bettina produced ten new breaches along the Tendra Spit (6), Dzharylgach Spit (3), and Ustrichne (Oyster) Lake baymouth barrier (1). This event was one of the largest on record, exceeding the six breaches produced by the November 1981 storm. Due to limited access to the study sites, satellite databases and communications with residents will be invaluable for documenting the evolution of new breach sites.