of the Great Cataract above. With the water head of 100 feet thus created, and a storage reservoir six miles long behind the dam, the discharge of the Great Lakes would generate a power that for volume, constancy, and low cost of development has no equal in the world, not even at the present Fall of Niagara. Such a dam near Lewiston and Queenston would create another Niagara Cataract with two-thirds the height of the present, and with a volume equal to that of both the American and the Horseshoe Falls.

An indirect result of the great power development at this dam might well be to prevent multiplication of the canals, pipe lines, and tunnels that now threaten to reduce Niagara River to a stream of uncertain width at the center of the Canadian channel, and to entirely dry up the American Fall.

To fully appreciate the advantages of power development by means of the proposed dam, as compared with developments at other points along Niagara River, it is necessary to study the nature of this remarkable stream from lake to lake.

Fall of the River

Niagara, perhaps the most famous river in the World, is the only natural outlet of the Great Lakes, Superior, Michigan, Huron, and Erie, whose com

BRIDGE OVER THE RAPIDS NEAR WHIRLPOOL.

bined area is 90,000 square miles. By a course 36 miles long the river discharges the outflow of the four upper lakes into Lake Ontario, and falls 328 feet on its way. It may thus be seen that of the entire descent from Lake Erie to

is 7 miles, and another 7 miles brings the river to its outlet in Lake Ontario.

The mean surface elevation of Lake Erie is 573 feet above tide water, and the descent of Niagara River to the foot of the Falls is 228 feet, so that the pool just below in the Gorge is 345 feet above tide level. At Lewiston, a little down stream from the foot of the escarpment, the river level is 245 feet above tide water, or substantially that of Lake Ontario. This gives Niagara a fall of 100 feet between the foot of the Cataract and Lewiston.

From crest to foot the mean height of the American Fall is about 165, and of the Horseshoe Fall 158 feet. The remainder of the drop of 228 feet between Lake Erie level and the foot of the Cataract occurs in the rapids of the upper river, on each side of Goat Island, and in its quiet stretch from Buffalo. Much of the descent of the lower river is concentrated in the two series of rapids that extend from about a mile above to a mile below, the Whirlpool, with a total fall of about 80 feet. At its head on Lake Erie Niagara River is about 2,500 feet wide. One mile above the Falls the width of the river is approximately 5,000 feet, and this narrows to about 1,000 feet at the American and 3,000 feet at the Horseshoe Falls.

feet on long stretches below, the river shows great variations in depth as well as in the velocity of its current. Between Lake Erie and the Falls the deepest part of the river channel runs west of Grand Island, east of Navy Island, and nearly coincides with the point of greatest recession at the crest of the Horseshoe Falls. In its upper, navigable portion the greatest depth of this channel is about 20 feet, and at the crest of Horseshoe Falls it is known to be as much as 16 feet, because a ship drawing that amount of water was carried over the Great Cataract by misadventure, some years ago.

In contrast with this moderate depth of water in the upper river, the pool at the foot of the Falls and the channel 1,000 feet wide that extends nearly to the cantilever bridge, a mile down stream, is 200 feet deep. Along this part of the river the descent and current are comparatively small. Beneath the cantilever and the steel arch railway bridges the river channel narrows to half its width above, decreases in depth to about 90 feet, and the water begins its downward rush to the Whirlpool. In that mysterious caldron whose lesser width is 1,200 feet, and whose unknown depth is estimated.

at 400 feet, Niagara River changes its direction of flow by ninety degrees, and then starts on its descent along the lower rapids.

The rapids above the Whirlpool where the descent is most precipitous have an estimated depth of only forty feet, and the depth of water in those below the Whirlpool is thought to be 60 feet. By the time the river passes Lewiston and Queenston the depth of water is again as much as 100 feet, and this is maintained to its mouth on Lake Ontario. Along the entire seven miles of Niagara Gorge from the Falls to Lewiston rise the continuous and often perpendicular walls of limestone and shale, fully two hundred feet high, that might easily form the sides of a great storage reservoir. In the seven miles of gorge from the Falls to the Escarpment there are only two important indentations of its rocky sides. One of these is the Whirlpool and its Ravine, and the other is the Devil's Hole, a smaller ravine, on the New York side, where the Seneca Indians ambushed and massacred a British supply train, in 1763. In both of these ravines the sides rise rapidly to the level of the top of the Gorge, and they simply add a little.

to the capacity of the reservoir that might be created by a dam between Lewiston and Queenston.

Variation in Head

Such a storage reservoir is the one thing needed to make Niagara an ideal power stream, by maintaining a practically constant head of water for the wheels of generating stations. Strange as it may seem, the heads of water now available at plants that draw their supplies from the upper river and discharge them at the foot of or a little below the Falls are subject to rather large fluctuations. These changes in heads of water of course affect the capacity of each pair of wheels, besides making necessary a large range of regulation to maintain. constant speeds.

A number of causes contribute to changes in both the head and volume of Niagara water about the Falls. Lake Erie is very shallow in comparison with the other four Great Lakes, having a maximum depth of only about 84 feet, and a strong east or west wind piles up its waters in one end while lowering them at the other. Apart from the action of the wind, the water level at the east end of Lake Erie where it flows into the

Niagara River has a variation of four feet. The East wind is known to lower the lake at the head of Niagara River as much as seven feet, and a west wind has at times an equal though opposite effect. Wind alone may thus produce a very large increase or decrease in the height and volume of Niagara River above the Falls. If the seven feet reduction in lake level, due to an east wind, happens to coincide in time with. the four feet reduction brought about by other causes, the water level at the head of Niagara River may be lowered eleven feet. As the deepest part of the Niagara channel near the Lake is only about 20 feet, it seems that the normal discharge of water may at times be increased or decreased fully one-half.

The possibility of extreme fluctuations. in the discharge of Niagara River is illustrated by the fact that within the memory of living men the American Falls has been entirely dried up during a strong east wind, so that one might walk across the bed of the river from the New York Bank to Goat Island. Another cause serves to multiply any changes in the head of water between the crest and foot of the Falls, due to the Lake Erie level, and that is the great