THE FORMATION OF THE EMBAYMENT AT DUFFERIN ISLANDS
I have come to the conclusion that the place where the falls at Niagara are now located was actually below ground level in the warm period before the last ice age. This was because the so-called Niagara Falls Moraine, having been deposited in the area by glacial movement in ice ages and seen today as the high ground on the Canadian side by the falls, extended further eastward in the warm period prior to the last ice age.
The key to understanding how we can know this is the embayment at Dufferin Islands, some distance upstream from the falls on the Canadian side. This is one thing about Niagara natural history that really stands out as requiring special explanation. What was it that could have formed the so-called "embayment" at Dufferin Islands? Looking on a topographical map or satellite photos, the embayment looks just about identical in both size and shape to the whirlpool in the Niagara Gorge. The only difference is that the whirlpool is much deeper.
Here is the map and satellite imagery link that I use: http://www.maps.google.com/ .
Just what created the embayment at Dufferin Islands? The whirlpool in the Niagara Gorge is what the river carved out for itself in order to make a abrupt change of direction, in that case because it met the looser fill of the St. David's River Gorge that had been buried by the last glacier. The lower Niagara River that carved the whirlpool is much narrower than the upper river at Dufferin Islands. Therefore, it had much more force concentrated on a limited area.
THE EMBAYMENT AT DUFFERIN ISLANDS COULD NOT HAVE BEEN FORMED BY ANY WATER DIVERSION FROM THE RIVER
As far as I can see, there is absolutely no sign of anything in the upper river, above the falls, near Dufferin Islands that would have diverted the very powerful stream of water southwestward that would have been required to carve out this embayment. Some people may say that something which formerly existed in the upper river near Dufferin Islands diverted the flowing water to carve the embayment. After careful thought, I cannot believe that for five reasons.
First, there is absolutely no trace of anything in the upper river near the embayment at Dufferin Islands which would cause such a diversion. If there was, it would have to have been made of very solid rock to divert the powerful stream to carve the embayment without out being worn away itself. If it was made of such solid rock and had been large enough to cause such a diversion, we should clearly see some remains of it today, yet we do not. The so-called Green Cascade, the low waterfall above the main falls that you can get near at the outermost of the Three Sisters Islands, stretches right across the river and points at Dufferin Islands, but that is a drop rather than a barrier and would in no way divert a narrow, powerful stream of water at Dufferin Islands. The Green Cascade can be seen in the satellite imagery as the white line of the Upper Rapids that is furthest east from the brink of the falls.
Second, we can see that the entire terrace on which Queen Victoria Park is now located was carved by flowing water after having been compacted by ice sliding westward across the slope of the rock strata. But that terrace bears no resemblence to the embayment at all. The park terrace follows a very wide curve, the embayment, a very tight curve.
Third, remember that until a few thousand years ago, the water level in the upper river near Dufferin Islands was at a much higher level than it is now, as a lake instead of a river. It began to drop only when the falls, eroding it's way southward, broke through the ridge at Hubbard's Point, causing the former Lake Tonawanda to drain. Simple physics tells us that in this case, the fast flow of water in the upper river, around what is now Dufferin Islands, would be mainly at the surface of the then-lake. The water at depths would be more stationary.
Thus, even if there was something in the river to divert the water to carve the embayment, it would not have had sufficient force to do so because the volume of water in the river would have been too large relative to the amount going over the falls to have had much force. At this time it was called Lake Tonawanda, not the Niagara River. The fact that it was called a lake implies clearly that the water was flowing very slowly or not at all.
Fourth, there is actually another mass in the upper Niagara River that diverts fast-flowing water. It is known as Goat Island. Yet, we see no sign of any kind of embayment forming on the shore of the mainland around Goat Island.
Fifth, it may be said that it would take a lesser force of water to carve the embayment at Dufferin Islands than to carve the whirlpool because the embayment is carved into a glacial moraine of relatively loose debris while the whirlpool is carved into solid rock. Yet, this is not accurate. The whirlpool in the gorge formed when the falls, eroding it's way southward, met the buried St. David's River Gorge from the previous warm era between the glaciers. The very reason that the river abruptly changes direction at this point is that the glacial debris filling the former river gorge was much looser than the surrounding rock layers.
Therefore, the whirlpool must have been carved from much the same type of material as the embayment at Dufferin Islands. Since the embayment is similar to the whirlpool in size and shape, we can logically conclude that it took fast-flowing water of similar velocity and volume to carve both.
The whirlpool in the Niagara Gorge is, of course, much deeper than the embayment at Dufferin Islands. But that can easily be explained by the hard layer of Lockport dolostone that causes the falls to exist. As the falls cuts it's way backward through the underlying limestone strata, this hard upper layer gradually breaks off in pieces so that a waterfall forms instead of a long and sloping rapids. The whirlpool was carved below this layer while the embayment was carved above this layer and was prevented from eroding deeper by this layer.
So, how did the embayment at Dufferin Islands form then? It is obvious that the embayment was once a whirlpool and we know that a whirlpool forms when a narrow and fast-flowing river has a reason to suddenly change direction. If the angle of the change of direction is great enough, a whirlpool is carved out to accommodate the water's abrupt change of direction.
THE FORMER ST. DAVID'S RIVER AND THE EMBAYMENT AT DUFFERIN ISLANDS
One glance at a map shows us that the course of the former gorge of the St. David's River, which the present Niagara River began following when it encountered the buried former gorge at what is now the whirlpool, also forms a line with the Green Cascade and Dufferin Islands. On Goat Island, it can be seen that there is a dip in the ground level in a line that continues from the Green Cascade. My conclusion then, is that the embayment at Dufferin Islands was once part of the St. David's River in the previous warm era before the last ice age.
However, that obviously cannot be a complete answer. Dufferin Islands does not look like a river gorge, it is an embayment or a former whirlpool. It must have been where a fast-flowing river once changed direction. A river formed, carrying water from what is now Lake Erie, flowing southwest along the approximate route of what is now Packard Road in Niagara Falls, NY. This was the warm era before ours and so the former Lake Tonawanda was not there. Since Niagara Falls, NY was originally named Manchester, after the industrial city of Manchester, England, I wish to name this the Manchester River.
The reason that this river took such a roundabout route is that we know that the Niagara Falls Moraine once extended much further eastward, and this drainage would have had to go around the moraine. The river changed direction in order to change the flow from the southwestward slope of the underlying rock layers in the area to the northward direction to empty into what is now Lake Ontario, and the whirlpool that formed to accommodate the sudden change of direction formed the present Dufferin Islands Embayment. The rest of the river flows from there to the Niagara Escarpment at the Ontario village of St. David's. The Manchester River is actually the branch of this river upstream from what is now Dufferin Islands.
That is the most logical, in fact the only logical, reason I can think of for the formation of the embayment.
WHY DID THE DUFFERIN ISLANDS EMBAYMENT FORM WHERE IT DID?
But then the next question is why the embayment at Dufferin Islands formed where it did. If we can see that the river at the area of the falls today occupies the valley that I have pointed out as the Niagara Valley that now hosts the falls, why didn't the St. David's River in the previous warm era, before the last ice age, also occupy that valley. Why would this embayment form some distance upstream from the lowest point of the valley?
There is a very simple and obvious answer. The Niagara Falls Moraine, seen today as the high ground on the Canadian side by the falls, extended further eastward. The St. David's River, downstream from it's change of direction at Dufferin Islands ran along the edge of the moraine. This line is marked today by the Green Cascade, extending across the Niagara River from Dufferin Islands, and the extending dip in the ground level on Goat Island, adjacent to the "Three Sister islands" and in a line with the Green Cascade.
The great masses of ice during the last ice age, sliding across the westward slope of the rock layers in the area, pushed the soil of the moraine westward to where it is now as the high ground on the Canadian side. It is this slope that creates the rapids above the falls, and can be easily seen on the American side around the falls area. In the posting "Why Are There Two Falls At Niagara"?, I explained how one such berg of ice must have slid down the southward slope in the LaSalle area of Niagara Falls, NY, carved Burnt Ship Creek on Grand Island, then slid along the westward slope to carve the ground away where the American Falls would later form.
So, this scenario provides a neat explanation of how the mysterious embayment at Dufferin Islands was formed and how it connects to what we know as the former St. David's River and why it is some distance upstream from where the low point of the valley which hosts the falls lies. This was at the edge of the Niagara Falls Moraine, and this means that what is now the falls was below ground level before the moraine was compacted to it's present position by the westward sliding movement of glacial ice across the rock strata of what is now the Upper Rapids at the end of the last ice age.
THE ADAMS POWER PLANT FOREBAY
The old Adams Power Plant, in Niagara Falls NY, has been in the local news recently. This was the world's first large-scale alternating current generating plant, according to the article on www.wikipedia.org "Adams Power Plant Transformer House".
The thing that has long caught my attention about this former power generating plant, most of which is no longer standing, is that the remaining section of it's forebay, through which water entered from the Niagara River to generate electricity by falling through a tunnel to the level of the lower river below the falls, points directly to the embayment of Dufferin Islands on the Canadian side of the river. This forebay can easily be seen in the satellite imagery on the U.S. side, between the river shore and a highway, some distance east of the eastern end of Goat Island.
The forebay of the power plant, most of which has been filled in but can be seen in one of the photos in the Wikipedia article, is located exactly where we would expect the Manchester River, the section of the St. David's River upstream from the embayment at Dufferin Islands, to have been. Water flowed along this route to the embayment at Dufferin Islands, where it changed direction and continued along the St. David's River through what is now the whirlpool and to the escarpment at the village of St. David's. This drainage route still exists across Niagara Falls, NY, althgough much reduced in water volume. After the last ice age and the draining of the former Lake Tonawanda, it was manifested again as Gill Creek.
My speculation is that when the Adams Power Plant was built, in 1895, the builders made use of a line along which the rock strata had been eroded away by this former river in order to speed construction of the forebay. This could be the reason that the power plant was located exactly where it was.
There was precedence in the area, during the Nineteenth Century, of making use of existing natural waterways in canal construction. The Erie Canal was dug as far as Tonawanda Creek, and then the creek became the canal. The two separated at North Tonawanda, near the Niagara River. Tonawanda Creek flowed into the river while the Erie Canal continued toward Buffalo along what is now the broad stretch of Niagara Street in Tonawanda (where Tops is located). The canal ran right alongside the river, with one of the canal's towpaths separating the two, until the canal was filled in as far as the towpath to form Niawanda Park. The Erie Canal continued from there, to Buffalo, along the route which is now occupied by the Interstate 190 Highway.
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