US-based TDI-Brooks has completed a large survey campaign offshore New York and New Jersey. Between January 2023 and February 2024, the company conducted an extensive site investigation program in two offshore wind blocks in state and federal waters.
TDI-Brooks carried out various tasks at different stages, such as geophysical surveys, UHRS detailed surveys, archaeological identification surveys, light geotechnical coring, and benthic sampling.
The projects involved surveying in excess of 20,000 line-km of analog and either single or multi-channel seismic lease blocks and cable routes along the coasts of New York and New Jersey.
The goals, determined by the collected data, were to assess the conditions of the seabed and sub-seabed, which may include potential risks (geohazards or man-made hazards) that could impact the installation of wind turbines and subsea cables in the future.
TDI-Brooks utilized three survey vessels, namely the R/V BROOKS McCALL, R/V MISS EMMA McCALL, and M/V MARCELLE BORDELON.
The geotechnical survey involved 150 pneumatic vibracores (pVCs) and over 150 Neptune 5K cone penetration tests (CPTs) gathered from both lease areas and along the offshore cable route (OCR).
Along with multiple export cable route surveys, a reconnaissance survey covering the entirety of the lease area with 150-meter spaced survey lines was conducted, followed by a more detailed archaeological survey with 30-meter spaced lines.
Survey sensors including dual head multibeam sonar, side scan sonar, sub-bottom profiler, UHRS seismic, single-channel seismic, and Transverse Gradiometer (TVG) were utilized.
The investigations involved two main areas of focus. The first area included measuring variations in water depth and slope changes, examining the morphology (composition of the seabed and lithology in the formations below in relation to local geology), identifying any natural or man-made obstructions on or below the seabed, such as rock outcrops, channels, depressions, gaseous fluid features, debris (natural or manmade), wrecks, industrial structures, cables, and others.
The second area focused on assessing any shallow geohazards that could affect the sites and future deep geotechnical soil studies within the top 100 meters beneath the seabed.
According to TDI-Brooks, the collection of data plays a vital role in determining the optimal location and design for offshore projects such as wind farms.
The company revealed in February 2023 that it won a geophysical, geotechnical, and benthic sampling survey contract to study seabed conditions within the project lease area and potential export cable routes off the US East Coast.
In terms of other news coming from TDI-Brooks, the company’s new research vessel, RV Nautilus , arrived in March on the US East Coast after undergoing a retrofit campaign. There the vessel will perform offshore wind work.