The reconnaissance level survey was followed by detailed geophysical, geochemical, and geotechnical investigations along multiple candidate submarine gas pipeline routes. The surveyed routes covered 28 miles connecting Salem with Weymouth via Beverly Harbor, Salem Sound, Massachusetts Bay, Nantasket Roads, and the Weymouth Fore River. The multi-phase investigation provided data to characterize the seafloor near-subbottom stratigraphy and supported permitting, design, and construction activities.

The geotechnical investigation (vibratory coring) was accomplished using OSI’s 37’ x 16’ trailerable coring platform R/V CanDu to acquire all project geotechnical cores allowing significant project cost savings.

Post-construction, numerous mappings were done using subbottom profiling, side scan sonar, magnetometer, hydrographic, and ROV surveys to assess the route.