October 2019 — Virginia, United States

Client: Chesapeake Tunnel Joint Venture

An acoustic measurement study to determine the underwater sound levels produced by DTH (down-the-hole) hammering, a new technology for creating casings for installing dock piles. Measurements were obtained with three bottom-mounted flow-shielded moorings at Thimble Shoal along the Chesapeake Bay Bridge Tunnel in Virginia. The sound footprint was determined for DTH hammering, both with and without bubble curtain mitigation, and compared to regulatory thresholds for onsets of behavioural disturbance and injury to marine mammals. The results suggest that only behavioural disturbance is possible.

June 2019 — Western Australia

Client: Advisian

A modelling study of underwater sound levels in Mermaid Sound associated with proposed development of the Scarborough Project Nearshore Component at the Pluto LNG field to assist in understanding the potential acoustic impact on key regional receptors including marine mammals, fish, and turtles. The study considered the driving of subsea piles which may be required to assist with pipelay operations close to the Pluto LNG facility, inside Mermaid Sound, and compared the sound levels against multiple effects criteria.

October 2018 — Western Australia

Client: Rio Tinto

A detailed review of the literature and international regulations and guidelines on impact assessment for pile driving noise for Rio Tinto’s Cape Lambert Port A Marine Structures Refurbishment Project. Includes a review of marine fauna present in the area and summarizes new or updated regulations and guidance relating to pile driving and other relevant noise sources since 2011 from jurisdictions in Australia, North America, and Europe.

A collaborative report with ERM.

March 2018 — British Columbia, Canada

Client: Hatfield Consultants

Appendix 18.18 – Underwater Acoustic Modelling Report

Predictive modelling of underwater noise from pile driving to inform the environmental impact assessment for the construction of a four-lane bridge across the Fraser River to connect the cities of Surrey and New Westminster, British Columbia. Pile driving noise is transmitted from the pipe pile through river sediments and sheet pile wall, and into the water. Sound levels and ranges to acoustic thresholds in water that may result in injury to valued ecosystem components such as fish (e.g. sturgeon and Pacific salmon) were reported.