When the Erie Canal was opened, was any drop in the water level of the Hidson River or Lake Erie noticed? Would something like this be taken into account before the construction of such a canal?
I assume the Panama Canal, connecting two oceans, was not going to have a significant (if any) impact on the water levels of the Atlantic or Pacific, but for smaller bodies of water, are any studies performed?
I know Lake Erie is huge, so I’m assuming no study was done, yet the water that was needed to fill the canal was significant and had to come from somewhere.
Or was the water in the canal insignificant to impact the levels of the Hudson or Lake Erie?
There’s actually an eight inch difference in height between the level of the Atlantic and Pacific sides of the Panama Canal. The Suez canal has about a 4 foot height difference – something known in the ancient world.
the Erie Canal actually goes up and down several times in its course – the canal crosses rivers on its own bridges (“aqueducts”). One of these still exists in Rochester, for instance, although the canal itself was long ago re-routed south of the city, and is still used as a bridge over the Genessee.
So the canal has always required locks to adjust the canal height, and these were taken into account when building the canal.
The causes for height differences even in sea-level canals are difference in temperaturem, salinity, tides, and Coriolis forces. Fascinating stuff. In river canals, of course, the rivers change height as they flow downhill. Water flows through canals, as well.
What you probably wanted to ask about was the Chicago Sanitary & Ship Canal, which allows water to flow out of Lake Michigan-Huron and eventually into the Mississippi River. Not long after the canal was opened in 1900, reversing the flow of the Chicago River, the other Great Lakes states sued over the “Chicago Diversion,” and a drop in the lake level was noted. A lock at the mouth of the Chicago River was finished in 1938 to control the outflow of fresh water from Lake Michigan.
We now believe the lake water levels vary quite a bit over a period of several decades, and in fact the level is now the lowest in recorded history, much lower than the drop that prompted the limitation on diversion.
Suez canal has no significant flow even though it has no locks. This explains why ancient canals didn’t develop into a river and then straight or gulf…
in fact the ancient canals clogged up and became forgotten.
Panama canal has locks.
The Panama Canal does not directly connect the two oceans, so the question does’t apply. The central section is made up of the freshwater Lake Gatun, which is 85 feet above sea level. Ships are raised and lowered from sea level to the lake by means of locks.
However, even if the canal was at sea level it wouldn’t cause any change in relative sea level. There would be a flow of water from one ocean to the other because of tidal and other differences (the Pacific being on average a few inches higher than the Atlantic in this area), but the flow would be trivial compared to the volume of the oceans.
was the Chicago Sanitary & Ship Canal, which allows water to flow out of Lake Michigan-Huron and eventually into the Mississippi River. Not long after the canal was opened in 1900, reversing the flow of the Chicago River, the other Great Lakes states sued over the “Chicago Diversion,” and a drop in the lake level was noted. A lock at the mouth of the Chicago River was finished in 1938 to control the outflow of fresh water from Lake Michigan.