Page 42: of Marine Technology Magazine (November 2021)

DESIGN UNDERWATER NOISE MITIGATION

LESSONS LEARNED IN

SETTING UNDERWATER

RADIATED NOISE TARGETS:

A BC FERRIES CASE STUDY

By Greg Peterson BC Ferries, Director of Engineering, Chanwoo Bae, BC

Ferries, Engineering Manager (Naval Architecture), and Derek White,

Vancouver Fraser Port Authority, ECHO Program Project Manager n a typical year, the waters surrounding British Colum- life, including the southern resident killer whales (SRKW), bia’s Port of Vancouver host approximately 3,000 deep sea which have been listed as endangered in Canada since 2003.

commercial vessels and 19 of the 35 ferries operated by With vessel-generated acoustic disturbances identi? ed by

I BC Ferries, one of the largest ferry operators in the world. Fisheries and Oceans Canada as one of four key threats to the

These waters are also home to a wide variety of aquatic wild- SRKW, the Vancouver Fraser Port Authority launched the En- hancing Cetacean Habitat and Observation (ECHO) Program in 2014 to better understand and manage the impacts of com- mercial vessel traf? c on at-risk whales, with a particular focus on vessel-generated underwater noise.

In moving towards this goal, in 2015, the ECHO Program began monitoring underwater noise through a cabled hydro- phone system installed in the Strait of Georgia, near the inter- national shipping lane. The hydrophone system continuously measured underwater noise, showing that peak noise levels strongly correlated with BC Ferries’ ferry schedule between

Tsawwassen and Nanaimo (Figure 1). This initial study com- pelled BC Ferries—one of the ECHO Program’s founding ad- visory working group members--to undertake research to bet- ter understand the underwater noise contributions of its ? eet.

MEASURING AND SETTING TARGETS FOR

UNDERWATER NOISE LEVELS

Between 2015 and 2017, BC Ferries contracted dedicated vessel sound trial measurements in addition to measurement

FIGURE 1: Sound Pressure Levels measured in the opportunities via the shipping lane hydrophone system. As

Strait of Georgia during a typical day.

part of this baselining effort, an unusual trend was noted 42 November/December 2021

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