Underwater Sound
The increase in activity at the North Sea has led to an increase of underwater sound. Construction of wind farms, seismic surveys, and maritime transport are the most notable sound sources that disturb marine life. We use underwater sound measurements to map the impact of these activities.
We are specialised in performing underwater sound measurements at sea. Over the past years we have performed measurements during the construction of various wind farms and during seismic surveys. We also perform measurements to characterise the source level of vessels. The measurement data is used as input for our Tritonic propagation model. We measure the presence of marine mammals in our project area using Passive Acoustic Monitoring (PAM) combined with visual observations (MMO).
Measuring underwater sound
We have a comprehensive range of acoustic measurement instruments for measuring underwater noise levels, either autonomously or in real time, and for detecting marine mammals.
We deploy these instruments on the seabed using bottom frames or perform measurements from (installation) vessels. Using our own internationally benchmarked analysis algorithms, we quickly and accurately analyse and report underwater noise levels. This can be done in real time during piling activities or afterwards when analysing data from research projects.
Installation of PAM Frames for Ecowende
We conduct ecological monitoring over a period of seven years at 14 locations in and around the Ecowende wind farm (see inset). The video below shows what the installation of a monitoring frame from an offshore installation vessel looks like.
Test installation of one of the 14 inner and outer frames near the Hollandse Kust West offshore wind farm
Measuring underwater sound
We have a comprehensive range of acoustic measurement instruments for measuring underwater noise levels, either autonomously or in real time, and for detecting marine mammals.
We deploy these instruments on the seabed using bottom frames or perform measurements from (installation) vessels. Using our own internationally benchmarked analysis algorithms, we quickly and accurately analyse and report underwater noise levels. This can be done in real time during piling activities or afterwards when analysing data from research projects.
Plaatsing Ecowende PAM Frames
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» Underwater sound measurements, e.g. piling activities, seismic surveys, shipping. » Monitoring marine mammals, e.g. density and distribution of harbour porpoises and other species.
View our underwater sound measurement projects
Effects of Dredged Material Disposal in the Eems
The navigational channel between the Eemshaven and the North Sea needs to be dredged regularly to remain accessible to seagoing vessels. The dredged sediment is disposed of at various disposal sites, which may have an impact on the local ecology. To assess these effects, flow conditions and sediment concentrations were measured at a disposal site during sediment disposal operations. Based on these measurements and a numerical modelling study, WaterProof assessed whether sediment disposal at location P0 could have significant adverse effects on the ecology.
Research into Scour Pits
Offshore wind farms use different types of foundations depending on the site conditions. The most commonly used foundation types are monopiles, gravity-based structures and jacket foundations. In collaboration with Leo van Rijn, WaterProof investigated the expected dimensions of scour pits around offshore wind turbine foundations. The study combined physical scale experiments carried out in WaterProof’s flow and sediment basin with numerical modelling.
Impact of EMF and Underwater Sound on Harbour Porpoises
Export cables are used to connect offshore wind farms to onshore substations, from where the electricity is fed into the national power grid. Electromagnetic fields (EMF) are generated around buried export cables as a result of the electrical current flowing through them. These EMF may potentially affect marine life. The magnitude of these fields and their potential impact are still largely unknown. We therefore work with several partners on different measurement and research projects to better understand and assess these effects. Research into the potential relationship between EMF and harbour porpoise presence within the Borssele offshore wind farm is one example.
