Sea Level Rise Impact on Compound Coastal-river Flood Risk in Klaipeda city (Baltic coast, Lithuania)

Due to climate change, extreme floods are projected to increase in the 21st century in Europe. As a result, flood risk and flood related losses might increase. It is therefore essential to simulate potential floods not only relying on the historical but also include future projecting data. Such simulations can give necessary information for development of flood protection measures and spatial planning. This paper analyzes the risk of compound flooding in the Dane River under different river discharge and Klaipeda Strait water level probabilities. Additionally, we examined how water level rise of 1 meter in the Klaipeda Strait could impacts Dane River floods in Klaipeda City. Flood extent was estimated with Hydrologic Engineering Center's River Analysis System (HEC-RAS) and visualized with ArcGIS Pro. Research results show that the rise of the water level in the Klaipeda Strait has a greater impact on the Central part of Klaipeda City, while the maximum discharge rates of the river—on the Northern upstream part of the analyzed river section. Sea level rise of 1 m could lead to the increase of area affected by Dane floods up to three times. Floods can cause significant damage to the infrastructure of Klaipeda Port City, urbanized territories in the City Center and residential areas in the Northern part of the City. Our results confirm that, in the long run, sea level rise will significantly impact the urban areas of the Klaipeda City situated to Baltic Sea coast.