Geological Diagram of Portage Dam Site

Portage Dam 1--medium.jpg
Portage Dam 2--medium.jpg

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Geological Diagram of Portage Dam Site


Beginning in 1890, recurring attempts were made to construct a dam in the Genesee River gorge so as to control flooding in the city of Rochester and generate electricity. After failed efforts at Mt. Morris, in 1896 attention turned to a site at Portageville and the state legislature authorized creation of the Genesee River Company.

William P. Letchworth was alarmed at the project's potential impacts, and by 1906 he had enlisted the aid of the American Scenic and Historic Preservation Society. These two diagrams were created by that organization as part of a multi-prong resistance to the dam project--along grounds of historical & environmental uniqueness of the gorge, and in this case its geological infeasibility.

The two diagrams appear with their original captions, the gist of which is to show that a proposed canal already had rejected the site because of its sandy composition. Remarks following the diagrams are offered by Prof. A. W. Grabau of Columbia University: "A break in this dam of quicksand such as is sure to occur from undermining by seepage if the lake is created, would carry the resultant flood into the present Genesee gorge near the Lower Falls and through the outer gorges to the flats below Mount Morris. It would not be difficult to estimate which of the villages of the flats would hr wiped out of existence. Probably few would escape. Unless it can be shown that a dam of quicksand from half a mile to a mile in length and 2,000 feet across, and extending 70 feet below the floor of the valley which it dams, can hold in check a lake 15 miles long and 118 feet deep and about a mile in width, and containing 15,000,000,000 cubic feet of water, the project will have to be abandoned."

The Portageville Dam project finally was rejected in 1911, although on grounds of economic "infeasibility" rather than geological unsoundness or historical preservation.


Green, Andrew Haswell (1820-1903)
Hall, Edward Hagaman (1858-1936)


American Scenic and Historic Preservation Society




Cooper, Ken


Item originally appeared in "Annual Report of the American Scenic and Historic Preservation Society," vol. 13 (1908): following p. 34. Scanned image, from the University of Florida George A. Smathers Library, courtesy of The Internet Archive.

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