; and (2) in a year in which the Great Lakes are not open to navigation because of ice of a thickness that occurs on average only once every 10 years, the Coast Guard shall keep channels and harbors in the Great Lakes open to navigation at least 70 percent of the hours that commercial vessels transit ice-covered waterways. (c) Report to Congress Not later than July 1 of each year, the Commandant shall submit to Congress a report on the icebreaking operations conducted by the Coast Guard in the Great Lakes for the most recent fiscal year for which data are available. (d) Coordination with industry The Commandant shall coordinate Great Lakes icebreaking operations with operators of commercial vessels. (e) Icebreaking in Canada (1) In general The Coast Guard shall not break ice in Canadian harbors or bays unless the requirements of subsection (b) will be met during such activity. (2) Waiver authority The Commandant may waive the prohibition in paragraph (1) on a case-by-case basis upon the approval of the Secretary for such waiver and notification to Congress of such waiver. (f) Definitions For the purposes of this section: (1) Commercial vessel The term commercial vessel means any privately owned cargo vessel of at least 500 tons operating in the Great Lakes during the winter season. (2) Great Lakes The term Great Lakes has the meaning given such term in section 118 of the Federal Water Pollution Control Act ( 33 U.S.C. 1268 ). (3) Ice-covered waterway The term ice-covered waterway means any portion of the Great Lakes in which commercial vessels operate that is 70 percent or greater covered by ice, but does not include any waters adjacent to piers or docks for which commercial icebreaking services are available. (4) Open to navigation The term open to navigation means navigable to the extent necessary to meet the reasonable demands of commerce, minimize delays to passenger ferries, extricate vessels and persons from danger, prevent damage due to flooding, and conduct other Coast Guard missions as required. (5)