Abstract
An Environmental Impact Assessment (EIA) of a planned 150 MW offshore wind farm at Horns Rev has been carried out for the marine biology and sea bottom in the area, and includes vegetation and benthic fauna. The study forms part of a total EIA of the planned offshore wind farm. This EIA study has been drawn up in accordance with the guidelines laid down by the Ministry of Environment and Energy in the publication, 'Guidelines for preparation of EIAstudies for offshore wind farms. Horns Rev is situated off Blaevands Huk, which is Denmark's most westerly point. It is a shallow reef with water depths between 2 and 9 metres and is primarily composed of sand, gravel and pebbles. The area designated for the wind farm lies directly south of Horns Rev and is dominated by sand with a median particle size of 0.3 mm. Along the edges, towards areas of greater depth, the particle size increases. There are areas of fine sand in the deepest area, and in isolated pockets within the proposed wind farm site. The sediment is characterised by a very low (<1%) organic matter content. On the basis of the expected impact from the establishment of the wind farm, it is not deemed necessary to carry out special programmes during the construction phase for monitoring of the environmental-biological conditions. A monitoring and control programme is recommended during the production phase in order to follow the copper concentration in bivalves, or alternatively to initiate recovery or elimination of the copper-laden waste. A control programme is recommended during the production phase in order to follow the establishment and succession of the fouling community on the wind turbine foundations and scour-protecting revetments.