NOAA returns to the Great Lakes to chart critical waters

To address a data gap in a key part of the USA's nautical navigation infrastructure, the NOAA ship Thomas Jefferson is back in the Great Lakes. Western Lake Erie, a high-traffic corridor for commercial and recreational vessels, has not seen a hydrographic survey since the 1940s. That data gap represents a navigational liability across one of the most active stretches of the Great Lakes marine transportation system.

This season, the Thomas Jefferson and its crew are mapping western and central Lake Erie and eastern Lake Ontario, with additional survey work planned inside Lake Ontario National Marine Sanctuary to identify critical habitats. The deliverables feed NOAA's broader portfolio of nautical navigation products and services, the infrastructure that keeps vessels safe, fishing operations efficient, and the region's ocean economy on sound footing.

Addressing the mapping gap

The Great Lakes are the least mapped region of the United States, and the gap is significant. Only 17% of the lakefloor has been mapped at high density, with much of the remaining chart data dating back decades. Modern high-density bathymetric surveys produce a fundamentally different quality of information, enabling detailed analysis that supports navigation safety, resource management and the growing blue economy throughout the region.

NOAA is addressing that gap from multiple directions. Navigation response teams deploy each year alongside larger vessel operations to survey priority areas, and this year their focus includes Thunder Bay National Marine Sanctuary, western Lake Erie, Braddock Bay and vicinity in New York, and Green Bay along the Michigan and Wisconsin shoreline. The surveys contribute to both the Lakebed 2030 collaborative mapping initiative and the Great Lakes Restoration Initiative's habitat mapping programme, advancing a long-term effort to bring comprehensive, high-resolution coverage to a freshwater system of extraordinary regional and national importance.

The Thomas Jefferson will be joined this summer by a DriX H-8 uncrewed surface vehicle operating near Oswego, New York, adding autonomous survey capacity to the mission. The DriX carries high-resolution multibeam sonar capable of mapping the seafloor and detecting objects throughout the water column and along the bottom. Rather than operating fully autonomously, the system runs under a supervised autonomy model in which a NOAA pilot remains engaged at all times and retains the ability to assume direct control when needed. The vehicle can sustain operations for up to four days before returning to shore for routine checks and refuelling, making it a practical force multiplier for a mission covering expansive survey areas.