Assessing Underwater Noise Impact From Marine Projects

Abstract A substantial number of marine infrastructural projects result in increased environmental impact on marine fauna during the construction and operational stages of the projects. A significant part of this impact is due to excessive noise. The absence of standard methods of underwater noise assessment and prediction increase the risk of unacceptable change to the marine environment as a result of offshore anthropogenic activities. Generally, the auditory systems of marine species are different from that of humans, however it is typical to attempt to extend the same approaches as used for human settings to marine ecosystems. The justification of such approaches is not provided, however it is well understood from a practicability perspective. Construction operations such as pile driving and dredging may result in significant noise increase and irreversible impact on marine species. This paper reviews relevant regulatory documents and summarizes considerations that are typically used to setting relevant underwater criteria for construction and operational noise. It also suggests approaches to groups of acoustic criteria that may be used to control and minimize underwater noise impact. General methods of modelling underwater noise impact are reviewed as a part of planning for marine projects and identifying the need for noise mitigation measurements and preparation of relevant construction and operation plans. These approaches may be used to identify relevant noise criteria and submit environmental effect statements to attain regulatory approvals.