Natural and human control of the coastal development. Baltic sea, Lithuania
Sea coast - a geomorphic system that maintains its stability through the exchange of sand between its individual elements. As environmental conditions change, the shore system changes by adapting to maintain its stability. Natural processes such as sea level fluctuation and extreme storms cause continuous shoreline change. Feedback effects create natural elements inhibiting external factors altering shore stability. There is a relative equilibrium between natural factors and the shore and in the absence of sudden changes the shore system retains its quasi-stability over a long period of time. This is reflected in the development of the Baltic Sea coast at Lithuania in the 20th century. During this period, of naturally developing coastline did not experience drastic changes. Both the position of the shoreline and the change in the volume of sand on shore did not undergo catastrophic changes. Everything changes radically when a human intervenes in natural processes by starting to develop economic activities on the shore. Especially significant changes occur during the construction or reconstruction of hydro-technical structures. In the case of Lithuania, the hydro-technical structures that caused the biggest changes were the jetties of Klaipeda and Šventoji ports and the pier of Palanga. Since the shore sand transfer resultant at the Lithuanian nearshore is directed from south to north, the resulting barrier cats this drift, disrupting the free circulation of sand along the shore and forcing sand to accumulate on the southern side of the jetty. Meanwhile, on the north side of the jetty, when the sand supply is lost, the coast begins to retreat. These changes are exacerbated by the deepening of the Klaipeda port cana