Storm-Surge Induced Water Level Changes in the Odra River Mouth Area (Southern Baltic Coast)

Halina Kowalewska-Kalkowska

doi:10.3390/atmos12121559

Abstract

The Odra River mouth area is a region of the Southern Baltic coastal zone especially prone to the influence of storm surges. In the present study, the height and extent of the Baltic storm surges, and temporal offsets of the respective maximum water level occurrences in the Odra River mouth area were explored using cross-correlation, cluster analysis and principal component analysis. The analyses were based on hourly water level readings retrieved from water gauging stations located along the lower Odra reaches and at the coasts of the Szczecin Lagoon and the Pomeranian Bay during storm surge years 2008/2009–2019/2020. The analysis of mutual relationships between water levels during storm surges indicated that the extent of marine influence on the lower Odra River and within the Szczecin Lagoon was variable during the studied surge events, and dependent on meteorological conditions (the strongest during the sustained occurrence of wind blowing from the northern sector), discharge from the Odra River catchment (the strongest at low discharge), ice conditions on the lower Odra (suppressing the storm surge propagation upstream), and general sea level in the Pomeranian Bay (stronger at high sea levels). The strongest correlation between sea levels at Świnoujście and water levels in the Szczecin Lagoon and the lower Odra was found at a 6–7 h offset. The extent of storm surges usually reached 100 km up the lower Odra channels, less frequently reaching 130 km away from the sea.

Highlights

The analysis of mutual relationships occurring between water levels during storm surges in years 2008/2009 to 2019/2020 showed that storm surges along the Pomeranian
Bay coast (Southern Baltic) determine the water level variability in the Odra River mouth area, involving the Lower Odra River network and the Szczecin Lagoon, and the height and extent of the surge, as well as the temporal offset of the maximum water level occurrence in this region, depend mostly on the character of the sea level changes driven by meteorological conditions, and on the overall Baltic Sea level, discharge from the Odra
The extent of storm-surge induced water level changes within the lower Odra River and in the Szczecin Lagoon depended on the distance from the sea but varied during the studied surge events and depended on the meteorological conditions, discharge from the Odra River catchment, ice conditions on the lower Odra and generalized sea level in the Pomeranian Bay

Summary

Introduction

Storm surges generated by tropical cyclones and mid-latitude low-pressure areas [1]. Are potentially hazardous natural phenomena, as they carry a risk of flooding, and pose an ecological threat to numerous coastal areas of the world. They cause enormous material losses and cause large numbers of casualties. Storm surges are recorded in estuaries and coastal lagoons of the nearly tideless Baltic Sea, for instance on the Neva River [12], the Curonian Lagoon, and the Nemunas River [13], on Vistula Lagoon [14], and in the Vistula River delta [15,16], as well as on the Szczecin

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Conclusion