Original article by Sarah Waters
Thunder Bay National Marine Sanctuary
Adapted by David Fitch
Communications Specialist at the Great Lakes Observing System
Part of the Great Lakes Bottom Mapping Working Group newsletter. Subscribe here.
Watch the recorded webinar about mapping Thunder Bay here.
The ice had barely retreated from the coast of northern Lake Huron in spring of 2019 when a group of researchers converged in Rogers City, Michigan.
They were there to map unexplored areas of Thunder Bay National Marine Sanctuary (TBNMS) and potentially discover new shipwrecks and natural features such as sinkholes, fish habitats, and interesting geological formations.
During the two-week expedition, researchers mapped areas using a multibeam sonar system aboard an autonomous surface vehicle called ASV BEN (Bathymetric Explorer and Navigator) from the University of New Hampshire’s Center for Coastal and Ocean Mapping.
Piloted by crewmembers on shore and using sonar and GPS, BEN collected data about the lake bottom that can be used to create high-resolution maps. The expedition also served as a test case, helping engineers improve BEN for future uses.
Researchers aboard the R/V Storm, operated by NOAA Great Lakes Environmental Research Lab, conducted mapping and surveying in adjacent areas of the lake. Sponsored by NOAA’s Office of National Marine Sanctuaries, this project was the first partnership between Thunder Bay National Marine Sanctuary and Ocean Exploration Trust.
These expeditions help to provide baseline information that will help the sanctuary better understand and protect these underwater shipwreck sites and can be used to produce lake floor habitat maps of coastal and benthic ecosystems. The sanctuary’s tenfold expansion in 2014 to encompass 4,300 square miles means that Thunder Bay now contains 99 new shipwreck sites and potentially 100 more that have yet to be discovered.
Mapping is set to continue when BEN hits the water again in May of 2021.
In addition, NOAA’s National Centers for Coastal Ocean Science (NCCOS) and TBNMS recently completed a mapping prioritization study that will help guide future lakebed mapping, research, and exploration efforts in sanctuary waters in Lake Huron. The study gathered the most urgent mapping needs from 24 local experts in order to identify common mapping priorities and better understand the resources of the sanctuary. Find the full report of the study here.
This project was explored at the Lakebed 2030 webinar on August 10, 2020.
Find the original story from NOAA Sanctuaries here.
Above: ASV BEN (Bathymetric Explorer and Navigator) is a custom prototype built by SV Global Unmanned Marine System for University of New Hampshire’s Center for Coastal and Ocean Mapping. BEN has a state-of-the art seafloor mapping system that can map depths reaching 650 feet. Photo by Ocean Exploration Trust
A processed bathymetry map of the lakebed in Thunder Bay National Marine Sanctuary using data collected by R/V Storm. Varying colors indicate different heights of interesting lakebed features (heights are exaggerated to make the features easier to see). Image by Ocean Exploration Trust/NOAA 
A processed bathymetry map shows the Lake Huron bottomlands in Thunder Bay National Marine Sanctuary using data collected by BEN. Varying colors indicate different heights of interesting lakebed features (heights are exaggerated to make the features clearer). This type of map may be used to characterize lakebed and habitats, as well as plan future exploration. Image by Ocean Exploration Trust/University of New Hampshire-Center for Coastal and Ocean Mapping
