TWO TREATMENTS OF SHORE EROSION IN EXTREME FLOODS ON U.S. GREAT LAKES

Robert J. Hallermeier

Abstract


This investigation addresses empirical evidence on wave action and shore erosion during extreme floods on Great Lakes coasts. Historical information shows that record coastal floods on the Great Lakes usually involve moderately extreme storms during relatively brief intervals with overall lake level much above the long-term average. The 100-year flood on U.S. lakeshores appears most likely to be accompanied by coastal wave heights with recurrence interval of about: three years on the four upper Great Lakes; or one-half year on Lake Ontario. Shore changes during the 100-year flood seem susceptible only to a coarse statistical estimate because available studies reveal Great Lakes erosion to be extremely variable in onset and amount. Two simplified erosion treatments are outlined here, one applying average annual recession rate for a locality, and the second, an empirical relationship originally developed for seacoast storm effects. The latter treatment appears verified by evidence from a Lake Michigan study, and such estimates of episodic erosion cross section are much lower than for extreme events on U.S. seacoasts.

Keywords


shore erosion; extreme flood; Great Lakes

Full Text: PDF

Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.