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HYDRODYNAMICAL AND GEOLOGICAL INVESTIGATIONS OF POSSIBLE DEEP HARBOUR SITES IN NORTH-WESTERN SAAREMAA ISLAND: OVERVIEW AND CONCLUSIONS

2001; Estonian Academy Publishers; Volume: 7; Issue: 2 Linguagem: Inglês

10.3176/eng.2001.2.02

2228-0820

Jüri Elken, J Kask, Tarmo Kõuts, U Liiv, R Perens, Tarmo Soomere,

Oceanographic and Atmospheric Processes

Saaremaa is the largest Estonian island located to the west of Estonian mainland.A new deep harbour, need for which is stated in the Saaremaa County development plan, is possible only in the north-western part of the island that is environmentally sensitive and belongs partly to the area of Vilsandi National Park.This part of the island is known as wintering area of Steller's Eider and the sanctuary for seals.Environmental impact assessment of the harbour site selection indicated environmental risks at all the considered sites.Discussion of the assessment results led to additional hydrodynamical and geological investigations of the three harbour location alternatives on the Tagamõisa Peninsula: Undva (Uudepanga Bay), Suuriku-Kuriku (entrance of Tagalaht Bay), and Vaigu (central part of Tagalaht Bay).The investigations contained geological and hydrographic field work and modelling of currents and waves.The results revealed that due to dominating cyclonic circulation and small current speeds in the Uudepanga Bay, the risk of oil pollution from the Undva harbour to nearby Vilsandi National Park is rather low.The risk of polluting Steller's Eider wintering area in the north from the harbour site is somewhat higher, but still small.Vaigu has a favourable wave regime, but the bedrock is covered by a sand layer amounting to 10 m thickness.The waves exceed critical value for sand movement frequently, indicating the need for repeated dredging of ship channels.In addition, contaminant dispersal from Vaigu has the worst pattern.Suuriku-Kuriku has been found the most suitable location for the deep harbour.The expected tough wave regime is not so critical because the high-wave wind directions are rather seldom.As a location of the deep harbour, Undva was found somewhat less favourable and Vaigu considerably less favourable.