Mariners are advised that the International Lake Ontario St. Lawrence River Board (Board) has ordered that outflows from Lake Ontario through the St. Lawrence River be increased in stages in order to help alleviate flooding conditions around Lake Ontario. The Board may release flows as high as 9,910 cubic meters per second (cms) at first and then to 10,200 cms. The Seaways plan to continue operations at these outflows. These flows will create velocities higher than normal in the navigation channels and variations in the normal current patterns may occur. Mariners are advised to take these conditions into account when transiting the Montreal-Lake Ontario Section. As a result of the high flows and effective immediately, no meeting or passing will be allowed in the following critical areas:
  • American Narrows, between Sunken Rock Shoal, U.S. LT 189 and Rock Island Light, U.S. LT 213
  • Brockville Narrows, between buoys 138 and 147
  • Wiley Dondero Canal, between CIP 9 (buoy 56) to mooring cells below Copeland Cut
Mariners are to adjust their speeds accordingly to accomplish this. Mariners should exercise caution when navigating in areas of high cross currents such as Galop Island, Toussaint Island, Ogden Island, Copeland Cut and South Cornwall Channel (Polly’s Gut). The Board will continue to assess water level and flow conditions to determine if further flow increases will be required. If the Board determines that it is necessary to increase outflows to above 10,200 cms, it will be necessary to suspend navigation intermittently prior to which another Notice will be issued. Mariners are reminded that there is a zero tolerance for ship’s draft in excess of the maximum permissible draft, as per Seaway Notice No. 8. Mariners are to operate at the lowest safe speeds to minimize their wake, particularly when navigating close to shore. Speed limits outlined in Montreal- Lake Ontario Notices to Shipping Nos.14 and 15 remain in effect. Information on outflows will be provided in special radio messages as required and these messages will be posted on our Great Lakes-Seaway website. Mariners are invited to provide feedback to the Traffic Control Centers on navigation conditions encountered due to the higher than normal outflows.