Pupienis, D., Jonuškaitė, S., Jarmalavičius, D., and Žilinskas, G., 2013. Klaipėda port jetties impact on the Baltic Sea shoreline dynamics, Lithuania.

Port of Klaipėda is Lithuanian Baltic Sea harbour, which construction began in 1835. From 1835 to 2002, Klaipėda port gate (jetties and Klaipėda port entrance channel) saw several stages of reconstruction. Within the last reconstruction works of Klaipėda port gate in 2002, the southern and northern port jetties were extended reaching 1300 m and 1400 m respectively, and the entrance channel was dredged to the depth of 14.5 m. The objective of this paper is to determine the tendencies of shoreline variations in the northern part of Klaipėda harbour, at the Melnragė, on the basis of the analysis of cartographic material from different periods (1835–2010), as well as monitoring data on coastal dynamics (1996–2012) and by applying empirical mathematical functions: the parabolic bay equation. The analysis of cartographic material showed that in the northern part of Klaipėda port at Melnragė (within a sector of 2 km), from 1835 until the end of 19^th century shoreline was advancing seaward, and from the beginning of the 20^th century until 2002 shoreline was slowly retreating. Since 2002 shoreline erosion has begun, which has particularly intensified in the recent years, i.e. 2010–2012. From 1878 to 2002, the greatest shoreline retreat ranged from 30 to 150 m, whereas in the last two years, shoreline has retreated from 20 to 30 m. It was determined based on field data analysis that the shoreline in the northern part of Klaipėda port develops in accordance with the parabolic bay equation. Also, on the basis of the parabolic bay equation, it was found out that after the jetties' reconstruction (2002) in 2012 the beach static equilibrium was reached. The extension of the northern jetty as well as its new deflection angle determined the change of wave diffractions point position, and consequently led to shoreline retreat and beach bay formation at Melnragė.