In the United States, developers are required to measure sound levels during offshore wind farm construction. Regulators use this information to compare against predictions from pre-project acoustic modeling and to manage expectations for subsequent piles. Scaling laws can help make predictions about sound levels by making adjustments to certain input parameters (e.g., water depth, pile size, etc.), which is a much simpler process than full acoustic propagation modeling. Here, two new scaling laws were developed using data from acoustic measurements taken during the installation of 85 piles in US waters. One was based on the cumulative sound exposure level over full installations and the other on all single-strike metrics. Full installation and all single-strike acoustic measures showed positive correlations with water depth and pile penetration depth. For single-strike metrics, “loud” statistics (maximum, 5%, and 25% exceedance levels) were positively correlated with the maximum strike energy and negatively correlated with average strike energy, whereas “quiet” statistics (75% and 95% exceedance levels) were positively correlated with the average and negatively correlated with maximum strike energy. “Loud” acoustic metrics were influenced more by the maximum single-strike energy, while “quiet” metrics were influenced more by the average energy. Even after applying these equations to compensate for the input variables, there was still considerable variability in acoustic metrics across installations, suggesting that there are other important factors influencing sound levels that were not accounted for here.

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Analysis of Measured Impact Pile-Driving Noise Associated with US Offshore Construction for Regulatory Oversight

  • Alexander S. Conrad,
  • Erica Staaterman,
  • Shane Guan

摘要

In the United States, developers are required to measure sound levels during offshore wind farm construction. Regulators use this information to compare against predictions from pre-project acoustic modeling and to manage expectations for subsequent piles. Scaling laws can help make predictions about sound levels by making adjustments to certain input parameters (e.g., water depth, pile size, etc.), which is a much simpler process than full acoustic propagation modeling. Here, two new scaling laws were developed using data from acoustic measurements taken during the installation of 85 piles in US waters. One was based on the cumulative sound exposure level over full installations and the other on all single-strike metrics. Full installation and all single-strike acoustic measures showed positive correlations with water depth and pile penetration depth. For single-strike metrics, “loud” statistics (maximum, 5%, and 25% exceedance levels) were positively correlated with the maximum strike energy and negatively correlated with average strike energy, whereas “quiet” statistics (75% and 95% exceedance levels) were positively correlated with the average and negatively correlated with maximum strike energy. “Loud” acoustic metrics were influenced more by the maximum single-strike energy, while “quiet” metrics were influenced more by the average energy. Even after applying these equations to compensate for the input variables, there was still considerable variability in acoustic metrics across installations, suggesting that there are other important factors influencing sound levels that were not accounted for here.