Posted this earlier, but got one of those Gateway Timeouts, so it must’ve not made it.
Anyway. is it true that in a certain area the Rhine does flow upstream? I should know this being German-American, but it’s one of those factoids which has eluded me, i’m afraid.
Tidal forces can cause a river to briefly change flow near the mouth but I think it’s pretty safe to say the Rhine doesn’t flow upstream or uphill. I’ve heard the same said about the normally dry Santa Cruz river in Arizona and think the misconception stems from the fact that the river flows north which is less common. In any event it always flows downhill.
I don’t understand exactly how a river could flow upstream, but here’s an interesting site on rivers that flow north. It does mention the Rhine as flowing in a northerly direction from Switzerland.
What the heck? I really don’t get that site, lel. What is in any way weird about a river flowing north? All other things being equal, there should be just as many rivers flowing north as flowing south, east, west or any point in-between.
Where on earth do these people get their ideas? Am I “higher up” here in London than the Pyrenees, just because I’m nearer the top of a world map? :rolleyes:
Somebody better inform Cecil that the War Against Ignorance is going to need a whole lot longer…
I grew up beside the Macleay River in northern NSW, 26 nautical miles from the mouth. The river flowed east when the tide was falling and west when the tide was rising, therefore reversing direction about four times per day. (Last time I was there it wasn’t flowing at all, but that’s because of the drought.)
However, it is impossible by definition for a river to flow upstream, since downstream is defined to be the direction it is flowing.
20 miles from the mouth of the Cape Fear the river switches direction also.
There is a rumor that the salt water can even slip upstream under the fresh water flowing downstream! Water flowing both ways in a river, what’ll they think of next? (This I’ve wondered about for years, anybody know if this is a real phenom?)
Weeks, I think your story about salt water under the fresh has some basis in fact. I think the salt water would be denser and tend to “sink” if there weren’t some factors that caused turbulent flow and mixing. I know that in the open ocean there are different layers of water with different salinity. The boundaries between these layers are called Haloclines, IIRC.
Well the fact is the salt water does flow under the fresh just like you said. The Army Corps of Engineers deepens the channel of the Cape Fear occaisionally ( deeper every time) allowing the salt water to make its way farther and farther up the river.
This throws whole ecosystems out of whack.
The first to take the hit are stands of Bald Cypress trees (think: Pogo) along the rivers edge. They cant take it. The trees back in the woods away from the river seem to do better, but they’re goners , too.
Like a domino chain, you can guess the rest.
Can the river flow both directions at the same time? That’s the rumor I hear, but it’s never been more than that. It would make sense that during a heavy rising tide where the ocean REALLY has a point to make, combined with a swollen river, say from rains, where the rivers’ point is equally timely, the phenomenon would have to exist.
From a purely logical standpoint, there’s obviously nothing weird about it. But, as the site points out, since almost all maps have North at the top, we subconsciously think of North as being “up.”
I know it’s not rational, but when I was in Egypt a couple of years ago, I was often confused about which way the Nile was flowing, because I found it hard to shake the “North is up” feeling. Spending a day and a night on a felucca got me in better touch with the river, and helped clear the cobwebs from my brain!
Technically the Mississippi River flows uphill. The delta end of the river is further from the center of the earth than is the mouth because the of the equatorial bulge of the earth. Centrifugal effect, or force if you will, is what does the job.
Growing up near the Fox river in WI we wre told only the Fox, the Nile, and one other river flowed north. Obviously this is untrue.
I also heard that this was for “navigatable” rivers, but the Fox river is* only navigatable because of the lock and dam system.
Brian
*or rather, was. The locks have mostly shut down partially due to sea lamprey issues, and also because they were not worth the expense.
I know that at certain times of the day on the Potomac one can drift a canoe upriver from the monuments to Georgetown, which would be great if I could catch any damned fish there. DC is about 108 miles from the Chesapeake by the Potomac. If I read that page right, the mean tide range is still just shy of three feet all that way upriver. Still, I don’t discount the possibility that the free ride I was catching was actually due to a very slight upriver breeze.
Tonle Sap lake is partially fed from May to October by the Tonle Sap river. After the rainy season ends, the same river reverses direction and empties part of the lake into the Mekong watershed.
I think it’s possible that the Rhine could do something similar to the Tonle Sap, at irregular times when rainfall is scarce inland but plentiful in the Netherlands. It is, after all, Low Country, and the rivers flow very slowly to begin with.
Darn, I should have remembered the Tonlé Sap, seeing as I’m going to be in Cambodia next month and taking a boat along that very river. I remember reading in the guidebook that the Mekong, when in full flood, overwhelms the Tonlé Sap, making it reverse its flow, but for some reason this thread didn’t trigger the connection…
I don’t remember ever reading anything similar about the Rhine, though.
Growing up in Florida, we were taught the same thing about the St. Johns River. I wonder how many times this lie has been changed to fit local circumstances. What’s scary is that even through high school, many of my friends clung onto this fact, even though even a cursory look at an atlas will tell you it’s wrong. After all, what about all those rivers flowing into the Arctic Ocean?
speculation It’s probably due to places wanting to associate themselves somehow with the glory of the Nile, which is afterall the world’s longest river. “Sure, our pissant river may not be big, but just like the Nile, it flows north. How many rivers can claim that?”