Yunlin Offshore Wind Farm is located at least 3km from the proposed Major Wildlife Habitat of Taiwanese White Dolphin; nevertheless, the increasing number of vessels within the Project area as well as underwater construction, i.e. piling during construction would emit underwater sound.
Therefore, the level of the underwater sound from the pile driving and possible influence on the Taiwanese White Dolphin was assessed. The results show that the direct impact on the Taiwanese White Dolphin in the Major Wildlife Habitat area appears to be minor after mitigation measures are taken.
The Project chose the best technical standard available worldwide to reduce the high noise level during offshore work, including:
- The area of Major Wildlife Habitat for Taiwanese White Dolphin is avoided by the ships or crossed by the shortest route and at a reduced speed
- A combination of two noise mitigation systems (NMS) that have been successfully tested in Europe - Double Big Bubble Curtain (DBBC) and Hydro Sound Damper (HSD) - are used in the Yunlin project during each piling process to always comply with the limit of 160 dB SEL
- A progressive piling process will be adopted: starting from low to maximal intensity.
- The entire piling period will be controlled by hydrophones to monitor the emitting of underwater sound.
- Furthermore an intensive marine mammal monitoring is carried out by trained observers to detect the absence or presence of marine mammals. When marine mammals are observed around the piling location, the piling process is stopped until the marine mammals have left the area
- In order to minimize nighttime noise impact to Taiwanese White Dolphin, no pile-driving operations are permitted from two hours prior to dusk to dawn.