I found myself loosely using that expression until a estuarine ecologist friend of mine, in the precision of a true scientist, corrected my language:
"Water flows downhill most of the time, but it flows 'down gradient' all of the time" he would say ... light-heartedly but also with insistence.
His case in point was Herring River Estuary.It's located up on the outermost arm of Cape Cod, tucked up in Wellfleet Harbor and reaching up into Cape Cod National Seashore. He spent a good chunk of his career working to restore tidal flow to its upper reaches, which historically had been blocked off by a dike.
What other instances come to mind?
The beach for one (as shown in the video clip above), where the tide rolls water up on the beach front, riding the momentary wave of an breaking swale, or the Central Arizona Project sending water uphill to Phoenix and Tucson by way of pumps and a canal.The paradox of "water flowing uphill but also down gradient" is resolved.
But more broadly speaking (and as proven in the video), doesn't water always find its way back to the sea.
I would say yes, most of the time.
But more broadly speaking (and as proven in the video), doesn't water always find its way back to the sea.
I would say yes, most of the time.
11 comments:
Gee, it still don't totally understand it. Coming from Holland, living below sea level, i kind of understand. But hoe does saying 'down gradiant' solve that problem?
Hering reversed the flow of the Chicago River in the early 1900s without pumps. I am not sure of the engineering behind it, but somehow he must have changed the gradient.
Do I have this right? Water can be MOVED up a gradient by pumps or the tide, but always FLOWS down a gradient.
Very interesting video. The information is very useful. Have a nice weekend.
Thanks for your comments.
J- It's a bit of a fine distinction to be sure. The difference is that downhill is usually set in stone, but down gradient can be hydraulically altered. Holland could be the premiere example. I am sure they use pumps to keep water on the other side of the levees.
S- That's another great example, and to think it was done without pumps. That's possibly one of the top 10 "hydraulic engineering" wonders of the world.
G- In the moment in time that it does it, water never betrays its urge to move "down gradient" ... usually down hill is down gradient, but not always.
A- Thanks, it's the sort of fine point that hydrologists can endlessly discuss, so hopefully its useful towards that ends.
Well --from a mountain gal from TN, About 99% of the time I see moving water, I think it is going DOWN. I guess I've seen some cascades and waterfalls where there are sloped areas along the way where the water goes UP, but it's the force that causes that to happen.. Hmmmmmm--interesting stuff!!!
Betsy
Well, there are the exceptions to every rule - Capillary action will cause water to "flow" against gravity and gradient. Course that's not a river...
I wonder if this is the same thing as a "reversing falls"? I'm sure there's lots of them, but the most famous one I'm aware of is in New Brunswick, Canada - it's a tidal thing.
Thanks for your comments.
B- That's another good example, even in rip-roaring rapids you see areas of back flow where water nonsensically flows lazily backwards before being drawn back into the main current. That water is flowing "down gradient" on a micro scale before finding its way back into the main stem and back down hill.
D- I didn't think of that one, you see it all the time in clay laden soils, and well known among the soil scientists.
D- Reversing falls! Now that's something I'd like to see.
It took me a second to get it but I got it. :-)
It's one of the finer points of hydrology, but also a fun one -- and one that's sure to generate some good discussion among water folks.
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