| Summary: | 碩士 === 國立臺灣大學 === 工程科學及海洋工程學研究所 === 106 === According to 4C Offshore, Taiwan Strait has the largest wind energy in the global offshore wind speed rankings. This area sustains wind energy throughout the year and provides favorable conditions for the development of offshore wind farms (OWFs). However, parts of the planned locations for the potential OWF are close to the habitat of the Chinese White Dolphin (Sousa chinensis). The huge underwater noise of marine engineering and long-term operation noise may cause behavioral effect and hearing impairment on marine mammals. Therefore, the research has two parts. Firstly, the large-area simulation of pile driving noise in Changhua County, Taiwan. The noise assessment is carried-off mainly 750 meters from the piling locations, where the cumulative noise level effect is evaluated in the assessment area which is also a habitat of the Chinese White Dolphin. The sound exposure level (SEL) and the cumulative sound exposure level with auditory weighting function for mid-frequency cetaceans in 24 hours (SELMF,24hr) are included in the noise impact assessment criteria. Secondly, the long-term underwater operation noise monitoring and data analysis of the offshore wind farm in Zhunan Township, Miaoli County. The actual measured data is used as the source level and simulation for the impact zone of multiple offshore wind turbines operating in the offshore of Changhua.
The underwater noise simulation includes using the Range-dependent Acoustic Model (RAM) to predict the influence of pile driving noise on conservation zone. The simulation results show that the overall noise impact range of southern Changhua offshore is larger than that of the northern and the cumulative effect may cause the behavioral effect. Mainly due to the different sediments, second because of the terrain; hence should be considered in noise reduction or away from the Chinese white dolphin habitat.
The long-term operating noise mainly has two fundamental frequency at 20 Hz and 27 Hz. The main operational frequency band is at the center frequency of 160 Hz and the maximum energy reaches up to 142 dB in the frequency range 10 Hz to 1000 Hz. This study will provide an assessment during the construction and operational period to mitigate the impact on marine mammals, and expected that it will strike a balance between eco-conservation and renewable energy development.
|
|---|
