Coastal erosion Poland
The Polish coastline is 1032 km long, but about 500 km excluding the coastline of the Szczecin and Vistula Lagoons. Of this 500 km, some 420 km is fringed with wide sandy beaches backed by dunes, about 80 km are cliff shores (1). The strengthened section of the coast, including cliffs and dunes, is some 137 km (2). The number of erosion-prone areas is higher than that of accumulation areas; most of the coastline is classified as stable, however, with only minor changes (+/- 50 m per 100 years) (1).
The Baltic Sea is practically non-tidal; tidal range is 6 cm for the Polish coast. … Two basic shore types exist: dunes and barrier beaches, and cliffs. Cliffs comprise about 100 km of the coastline and are cut into Pleistocene sediments (3).
Poland’s coast can be split into three different areas reflecting major physiographic and economic differences along the Polish coast (3):
- Area I mainly covers the Odra Estuary (and the conurbations of Szczecin and Swinoujscie).
- Area II encompasses the western and central-eastern dunes, cliffs, and the open sea barrier beaches (including the Hel Peninsula).
- Area III covers the Vistula Delta (and the conurbations of Gdansk, Sopot, and Elbag).
The analysis of the south Baltic coastal changes during the late 19th and 20th century has revealed the intensification of erosive phenomena within all elements of the coastal system. In addition to an increase of sea level rise over the last decades, the occurrence of storm surges has become more frequent—an effect associated with changes in atmospheric circulation. These phenomena have caused the intensification of erosive changes and the increasing necessity of protection of affected shore segments (3). The highest storm surges associated with the inflow of water from the North Sea, causing severe erosion and flooding, were recorded in 1874 (1.96 m above Mean Sea Level) and in 1913/1914 (1.95 m above MSL) (1).
Currently, the total length of coast threatened by moderate and high erosion amounts to about 208 km, approximately 41.5% of the open sea coast. This includes the important Hel Peninsula. It is expected that over 70% of the shore length would be subjected to moderate to great erosion threats in the future. Over the next decades we can expect that the most threatened shore segment will be located in the Vistula outlet region and at many coastal segments of the central coast (3).
Erosion is increasing in Poland (8). While sea level rise contributes to a background recession of the Polish coast, the increased rate of coastal change mainly reflects the increasing number of storms from the westerly and northwesterly sectors and direct human influence. In the west and centre of the Polish coast, large disturbances to the littoral drift occurred because of the extension of harbour breakwaters at Kolobrzeg, Darlowo, Ustka, and Leba, which were constructed in the second half of the 19th century. These port breakwaters have significantly interrupted the predominantly easterly sediment transport. After construction of the breakwaters, accretion cones formed updrift (to the west), although these are currently decreasing in size because of a lack of new sediment input. This downdrift starvation has led to the development of erosive bays with a longshore length of 3 to 47 km (3).
The regions with the highest threats are associated with the spits of coastal lagoons, the Hel Peninsula, and the coastal lowlands near the harbours, and in the area of the Szczecin Lagoon and, most particularly, the Vistula Delta (3).
Area I mainly comprises agricultural land. In this area, the western part of the Polish coast, erosion is not a big issue. In Poland protective investments against sea level rise should mainly be undertaken along the west and east coasts, where economically justified, while along the central coast, only more localised protection would seem appropriate (3).
The central region of Area II is subject to intensive erosion over the last few decades (exceeding 5–7 m/y from 1971–1983) (7), which makes it one of the most vulnerable stretches along the Polish coast. Infrastructure measures have been taken, however, to improve the preservation of natural values and reduce the risk of storm-induced flooding. … The highest percentage (27%) of threatened Polish coastal natural area (unique on a European scale) is located in the region of the Slowinski National Park (3).
The Hel Peninsula, a large spit separating the Gulf of Gdansk from the open sea, is most vulnerable, and will become a small island if no protection measures are applied. It is 72 km in length, and the spit locally narrows to 100–200 m. The erosion rate from 1971 to 1983 was assessed as medium (0.5–1 m/yr). … This will require significant protection measures in the form of beach nourishment and local dikes. … The cliff coasts are the sources of sediment for maintaining the budget of the coastal sediments; therefore, only cliff segments whose defence is absolutely necessary should be protected (3).
Area III is the most vulnerable area for economic reasons when compared with the other coastal regions in Poland. … Full prevention measures should be considered to prevent any loss of this important industrial, scientific, and cultural centre of northern Poland. The existing dykes will become too low under the projected climate change scenarios (3).
Protective systems have already been developed for about 26% of the Polish coastline. About 98 km of the coast are fronted by groynes, while 41 km are protected by light and heavy revetments. The highest level of coastal protection exists along the 126 km long Jaroslawiec–Swinoujscie part of the Polish open coastline, where coastal defence structures extend over 71 km. The Hel Peninsula, Gulf of Gdansk, is protected along 34% of its length (3).
Between the 1900s and 1940s, groynes were the main type of protection used along with some light and heavy revetments. … At the end of the 1970s artificial nourishment was introduced, and this is now the established methodology used to protect 56 km of shoreline (3).
Coastal flood protection in Poland is designed for a 100 year return period of storm flood levels (4).
Full protection of the Odra estuary requires preservation of the polders on the periphery of the estuary. … All existing polder dykes must be adapted to the projected situation, and many new dykes must be constructed. … Wharves in ports and urban areas must also be raised (3).
Depending on the sea level rise scenario, in total 107 - 280 km of new dykes must be constructed in Area I. The lengths of upgraded dykes are 243-324 km. The cost of full protection in Area I is estimated between US$0.5 billion and US$2 billion, i.e., generally less than 10% of the value of the lost property and land (3).
To protect the most important places in Area II, new polders are required together with new facilities such as pumping stations, drainage, and other infrastructure, while older polders must be redesigned. … Finally, the full protection option for Area II embodies the construction of more than 200 km of new dykes as well as the upgrade of up to 290 km of dykes, depending on the sea level rise scenario. These dykes are partly required around the coastal lakes and partly along the rivers to protect adjacent coastal lowlands (3).
Depending on the sea level rise scenario, 13-52 km of new dykes, and the upgrade of 600-647 km of existing dykes are required. A substantial part of the urban area of Gdansk is in the hazard zone under average sea level rise and should be protected by a system of dykes, including along the water canals that connect the port and city with the sea. Moreover, the system should include storm gates at the mouth of Martwa Wisla and improvement of drainage and pumping systems. … Regular monitoring will be necessary on the most threatened coastal segments including those associated with the newest investments in the coastal zone, such as the landfall of optical fibre lines and gas pipelines (3).
The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Poland.
- Furmańczykk, K. (2013)
- Przyscłość (2006), in: Furmańczykk, K. (2013)
- Pruszak and Zawadzka (2008)
- Ministry of the Environment and the National Fund for Environmental Protection and Water Managementof the Republic of Poland(2010)
- Pruszak (2000), in: Pruszak and Zawadzka (2008)
- Zawadzka (1999), in: Pruszak and Zawadzka (2008)