# Analysis of the Accessibility of the Swinoujscie-Szczecin Fairway for Deep-Draught Ships
## 5 Summary  
An analysis of the results for Swinoujscie, I Tor Gate, Chelminek, and Szczecin shows:  
* the highest probable numbers of expectations per year for vessels with maximum draught occur in Swinoujscie ranging from 2.18 for the permitted water level of 465 to 5.28 for the permitted water level of 475;
* the average waiting (duration) times for admissible water levels are comparable for the examined water levels from 465 : 475 and are, respectively, for Swinoujscie from 7.31 h to 8.30 h, for Trzebiez from 10.15 h to 14.65 h, and for Szczecin from 13.79 h to 17.96 h.  
Taking into account the possibility of a daily waiting time of four ships per year with draught T = 11.2 m caused by low water levels, it is possible to assume that the permissible lowering of the water table level in the Swinoujscie-Szczecin fairway for bulk carriers, tankers, and LPG carriers with maximum draught entering the ports of Szczecin, Police, and Skolwin (designed) is equal to:  
\[\Delta\text{h}=0.25\text{ m}\]  
In the long term, the accessibility of the Swinoujscie-Szczecin fairway may be influenced by ongoing environmental changes. Sea-level rise could gradually increase the average water depth, potentially improving access for deep-draught vessels. However, extreme weather events, such as storm surges or prolonged low-pressure systems, may lead to more frequent or severe fluctuations in water levels, temporarily reducing navigability. Additionally, sedimentation processes in the Szczecin Lagoon and river sections may require more frequent dredging to maintain the designed depth. These factors underscore the importance of ongoing hydrological monitoring and adaptive management of fairway parameters in the context of climate change. The outcomes of this study may assist in operational decisions at the port level, especially during periods of low water. The presented modelling approach can be integrated into decision-support tools to assess whether incoming vessels with specific draughts should proceed or wait. By incorporating real-time water level data, the method may contribute to dynamic traffic scheduling, reducing delays and optimizing port throughput. Furthermore, the identification of critical \(\Delta\)h thresholds can inform policy decisions regarding acceptable risk levels, dredging priorities, and investment in fairway monitoring infrastructure. The methodology adopted in this study relies primarily on the statistical analysis of historical water level records and the application of a deterministic threshold-based model to evaluate fairway accessibility. While this approach provides a clear framework for assessing \(\Delta\)h-based entry conditions for \"maximum vessels\", it has certain limitations. The model does not account for interannual hydrological variability, potential long-term changes in bathymetry, or sediment dynamics that may alter the under-keel clearance (UKC) and affect fairway depth over time. Additionally, meteorological extremes (e.g., storm surges, droughts) and climate-induced trends are not explicitly included. These factors could be integrated into future analyses through the use of probabilistic models, real-time bathymetric monitoring, or hydrodynamic simulations. Expanding the methodology to incorporate such variables would allow for a more comprehensive and realistic assessment of the long-term navigability of the Swinoujscie-Szczecin waterway, particularly under scenarios of climate change and increased maritime traffic. Comparative Estuarine Case StudiesTo provide broader context for the analysis of fairway accessibility, selected European river estuaries with similar operational characteristics were reviewed. In the case of the Sulina Channel in the Danube Delta, which connects Romanian inland ports (e.g., Galati, Braila) with the Black Sea, access is limited by fluctuating water levels, sedimentation, and river discharge dynamics [39].