Initiation and evolution of gullies along the shoreline of Lake Huron

Over one hundred gullies are deeply incised into Algonquin Bluff along the eastern shoreline of Lake Huron. Aerial photographs between 1930 and 1992 were used to measure temporal changes in area and length of a sample of forty-four gullies. Regression analysis shows that gully area and length have increased in a linear fashion, and that gully initiation occurred in the nineteenth century. Gully initiation coincides with deforestation and settlement of the area. Surface drainage was redirected into drainage ditches, concentrating the flow and enhancing gully erosion. Natural processes associated with climatic fluctuations are probably insufficient to cause gully initiation, but may contribute to ongoing gully expansion.