The value of the seas and the seabed as a natural resource has increased greatly
over recent years, with the number and scale of marine activities increasing in
proportion. Many of man's offshore activities cause underwater noise. This may include
noise from sources such as ship movements, to the extreme levels of underwater noise
generated during piling and the use of explosives underwater. Activities that generate underwater
sound in the marine environment have the potential to impact upon marine receptors.
Kongsberg Maritime has engineers and scientists experienced in working in the
offshore environment, and in measuring and assessing underwater noise to stringent
standards dictated by specific customer and government requirements.
We offer high data rate, underwater noise recording systems to measure noise
in the offshore environment. These systems use calibrated hydrophones, traceable
to international standards, together with signal conditioning amplifiers and digital
data acquisition systems.
Underwater Noise Recording Equipment
Kongsberg Maritime’s underwater noise recording equipment has been specifically
developed for rapid deployment at incremental ranges to monitor and measure noise
in and around offshore civil engineering and military activities. By measuring noise
at many different ranges from the source (transect method), the propagation loss
of the underwater noise in a particular environment can be measured and subsequently
modelled. The equipment can be hand portable, and has been ruggedised for deployment
in the offshore environment.
Underwater Noise Analysis
In support of underwater noise assessment activities Kongsberg Maritime are able
to undertake the following services:
- Estimation of Source Level and frequency content of underwater noise from
offshore construction activities including pile-driving, drilling, seismic surveys,
wellhead severance, cable trenching and pipeline laying, underwater blasting,
boat movements and shipping, and aggregate suction dredging.
- Modelling of underwater sound propagation using narrowband and broadband
acoustic propagation models.
- Modelling of underwater noise in the region of sonar and civil engineering
and estimation of impact zones for marine mammals, fish and human divers. Modelling
and measurements are usually undertaken using broadband peak, or peak to peak
level, RMS Sound Pressure Level and Sound Exposure Level, and weighting scales
such as the M-Weighting and dBht for species of marine mammal, fish and human
- Offshore data collection programmes to obtain calibrated measurements, from
background sea noise levels to those encountered during underwater blasting.
- Measurement of baseline (background sea noise), construction and operational
noise to regulatory standards. Estimation of any impact zones or zones of audibility
for fish and marine mammals by comparison with species hearing thresholds and
background sea noise.