Application of shore sediments accumulated in navigation channel for restoration of sandy beaches around Pärnu City, SW Estonia

Abstract

Sandy beaches high in recreation value provide 16% of over 4,000 km long shoreline of Estonia. The shore processes associated with climate change have remarkably accelerated over the last decades. Many sandy shores have suffered from strong erosion including an excellent former beach at Valgeranna. The jetties, which were built in the 1860s to protect the navigation channel of Port Pärnu from choking, have prevented the natural sediment transport along the coast from south to north. At the same time, the sandy beach in Pärnu is expanding and part of the sand accumulates with strong storms also in between the jetties reducing the width of the shipping channel. The channel needs regular dredging but the dredged sediment has been taken far away to the open sea and accumulated on the seabed so far. The current paper addresses the possibilities of using that sand for beach restoration in destructed and eroded areas. An overview of the applied methods and measurements during the field studies are given. The results of modelling the processes of wave activity and sediment transport are discussed. Recycling of shore sediments is an important measure in sustainable coastal zone management. Different options and scenarios are analysed in order to find out the most reasonable ways to bring the sand back onto the beaches and stabilize the natural processes. Support from the state by working out respective laws and regulations would be motivating as well.