Underwater noise

Underwater noise assessment & modelling

Port expansions, dredging, offshore wind, defence activity and marine construction all generate underwater noise. Regulators, stakeholders and the community expect that noise to be understood and managed. Resonate helps you do that. Marine acoustics is complicated – winds, tides, seabed, temperature, and density cause sound to propagate, travel, reflect differently. We understand this complexity. At Resonate, we measure, model and assess underwater noise, making it simple to secure approvals, comply with conditions and protect marine life.

Our acoustic engineers have been on the high-tide mark for underwater noise, since well before it was a mainstream requirement in Australia. Our team have held expert roles on the Ichthys Project Dredging Expert Panel and also led the technical development of the South Australian Underwater Piling Noise Guidelines (2012). This was the first guideline in Australia to tackle one of the most significant sources of underwater noise.

That experience sits behind every underwater noise assessment we deliver.

In 2023, we helped redevelop the Underwater Piling and Dredging Noise Guidelines (2023) for the SA Department for Infrastructure and Transport. From this extensively peer-reviewed update, the guidelines were expanded to include underwater noise from dredging and accounted for effects on fish and marine turtles, including the development of a Marine Fauna Noise Threshold Calculator. We have written about what the changes mean for projects here.

SEASOUND, for underwater noise modelling

Sound behaves differently in water than in air. It can travel faster and carry further, shaped by depth, seabed and temperature. Consequently, land-based assumptions about how far noise travels, and how loud it is when it arrives, risk overstating or understating its impacts. Either outcome costs a project: overly conservative conditions on one side, and potential additional mitigation measures on the other.

Leveraging our extensive inhouse experience in marine acoustics over decades, Resonate has developed an industry-leading underwater noise modelling tool, SEASOUND. SEASOUND predicts how noise propagates through the real underwater environment. In line with industry standards, it accounts for water depth, bathymetry and seabed type, identifying where noise crosses the thresholds that matter for marine fauna. We can model source activities common to a variety of marine projects, including impact and vibratory pile driving, dredging, airgun surveys, and vessel movements.

SEASOUND assessments hold up against current criteria, including the NOAA Technical Guidance (2018 and 2024 updates) for marine mammals and the Popper et al. (2014) guidelines for fish and turtles. Results are weighted and cumulative by hearing group, which matters because the difference between a single pile strike and a full piling campaign is where under-assessment most often occurs. We can output mapped contours and safety zones that can be provided directly to regulators and stakeholders, and exportable data for your EIS or management plan.

Because we develop and maintain SEASOUND ourselves, we can adapt it to unusual activities, species or regulatory settings rather than fitting your project to a fixed template.

Our underwater noise services include:

Baseline and long-term underwater noise monitoring, using our own in-house logging equipment deployed on site for extended periods
Noise modelling for construction and operational phases of offshore and nearshore developments
Impact assessment against injury, behavioural and cumulative exposure thresholds
Safety zone and shutdown distance design for piling, dredging and underwater blasting

Compliance monitoring and comparison against approval conditions
Advanced signal processing and propagation modelling
Ship noise, radiated noise and vibration
Environmental impact statements, management plans and peer review
Expert evidence and contribution to government policy and guidelines

Project experience

Our experience in marine acoustics spans Australian and international waters, across ports, defence, energy and coastal infrastructure. Representative projects include:

Nuclear Submarine Construction Yard EIS (SA)
Northern Water Project EIS (SA)
Darwin Shiplift and Darwin Naval Base EIA (NT)
Groote Island Wharf Infrastructure (NT)
Granite Island Causeway Replacement, underwater and airborne noise monitoring and management (SA)
Port Bonython Jetty remediation, hydro-blasting underwater noise modelling, assessment and validation (SA)

Mardie Project (WA)
Boskalis SPV (WA)
Southern Launch Rocket Facility EIS (SA)
Adelaide Desalination Plant (SA) and Victorian Desalination Project EES (Vic)
INPEX Ichthys LNG Project (NT/WA), including the Ichthys Project Dredging Expert Panel
North Haven Marina dredging and Kingscote piling underwater noise monitoring (SA)
Port Ambrose Deepwater Port and Hudson River piling (USA), and seabed survey ESIA work in Honduras

Research

We publish our methods and results so they can be tested by peers. Our recently published work on underwater noise includes Measurement and Mitigation of Underwater Noise from Piling in Shallow Water Environments (Coasts & Ports 2025), and papers on piling vibration prediction methods, underwater noise from impact driving of small piles, and cutter suction dredge noise in shallow water. For more information on our marine acoustics publications, click here.

If your project is in, on or near the water, we’re here to help. Early advice on underwater noise broadens the available options for management and simplifies approvals. Contact us today to speak to an acoustic consultant.