The first ever noise study in harbours

At Haven Dredging, we’re proud to lead the sector, spearheading new innovations and developments, and conducting valuable research to make improvements in our maritime processes for the good of the wider environment.

Our innovative hydrodynamic dredger, Tiamat, was developed as a viable solution for maintenance dredging and agitation dredging, whilst raising awareness around environmental issues as a result of these more traditional methods in the port and dredging community. It also provides businesses with the opportunity to choose a more responsible, sustainable and economical method of dredging.

In the world’s first ever study into agitation dredging noise in harbours, we were keen to understand more about the impact of Tiamat on marine life below the surface. We know the significant benefits – environmentally, financially and for resourcing – and through our extensive research and development during trials in Tiamat’s development, we know how it works underwater and have an understanding of how marine life interacts with it and near it, but we wanted to know more.

We teamed up with the environmental hydraulics consultancy, HR Wallingford, to conduct a comprehensive survey, modelling and measuring the marine noise of Tiamat. The noise levels were examined and analysed against a traditional, Trailing Suction Hopper Dredger (TSHD), at Harwich Harbour, in Essex, UK, in April and May 2023.

We used the US-based, National Oceanic and Atmospheric Administration’s guidance of approximate sound pressure level (SPL) thresholds at 180 dB for whales and 190 dB for seals.

We are delighted to confirm that Tiamat has been confirmed to be below the safe levels for marine mammals and fish, and is significantly quieter than a small TSHD.

When being pulled by a small workboat, the noise level of Tiamat was around 170 decibels (dB), while a 3,500 cubic meter TSHD, was around 185 dB. It is noted in the study, Measurements of Tiamat and TSHD Noise Disturbance: “The measured sound pressure levels emitted from Tiamat (and the Bella workboat) are below the levels associated with direct injury to marine mammals.” It also states that fish are also unlikely to be hurt.

As well as being quieter, Tiamat provides a cleaner and greener method of maintenance dredging, that is easy to deploy, adaptable and at a lower cost.

We are committed to working with nature, for nature and to sustain nature. The results of this study are testament to the years of research and field testing that has been put in to creating Tiamat.The full report is available upon request. For more information about Haven Dredging and Tiamat’s many benefits, please visit www.havendredging.com.