Technical World Magazine, March, 1909.

Conquering the Hell-Gate of the Lakes

By Len.G. Shaw

…

Using Stony Island, a marshy tract some few acres in extent, as a starting point, the contractors began construction of the largest cofferdam ever undertaken. Dredges were used in casting up the walls of rock and clay, taken from the river bed at various points in the new channel where excavation in the old way was comparatively easy. An area 2,800 feet in length and with an average width of 1,600 feet was enclosed by a wall some forty feet through at the base, reaching ten feet above the surface of the river, and at the top being wide enough to permit the laying of a narrow gauge railroad track if desired.
…

With the water out of the cofferdam, excavating was undertaken. Great towers, more than one hundred feet in height, and mounted on tracks permitting their being moved wherever desired, were erected 720 feet apart, being connected by cableways capable of sustaining a weight of ten tons, and on which ran ten-ton "skips" or trays, operated by compressed air and manipulated so that they could be dumped in midair without the slightest delay.

Channelers were put at work, these knife-like devices cutting courses through the rock lengthwise of the channel and some six feet apart. At regular distances across the proposed channel holes were drilled at angles, filled with dynamite, and the charge exploded. Then the sixty-five ton steam shovels were put in operation loading the skips, and the task of gouging out a channel through the solid Niagara limestone was well under way.

This channel is actually part of the border between the United States and Canada. Looks like they cut the island in half right down the border!

If you transit this channel at night it looks just like an airport runway being so straight and lighted at the margins.