This product has been produced by the St. Lawrence Global Observatory and includes data and services provided by the Canadian Hydrographic Service of Fisheries and Oceans Canada. The incorporation of data sourced from the Canadian Hydrographic Service of Fisheries and Oceans Canada within this product does NOT constitute an endorsement by the Canadian Hydrographic Service or Fisheries and Oceans Canada of this product.”

The Dynamic vertical clearance is the distance between the obstruction and the surface of the water for the indicated date and time.

This distance is computed using the charted vertical clearance reduced to chart datum and corrected for water level forecast or prediction.

The Dynamic vertical clearance is computed using water level forecast for periods under 30 days. Beyond this period, water level prediction is used.

A description of technical terms can be found in this glossary.