A river close to where I live only occasionally breaks the sandbank to enter the ocean. Yet only 10km upstream it is a vibrant perennial waterfall (30m drop). Where does all this water go if near the estuary mouth it’s mostly still and essentially stagnant?
Could just be evaporation or that it does reach the ocean, through the porous sand near the coast, or it could be that the water is being extracted at various points for irrigation or to be purified for humans to consume.
A river is a narrow channel going fast, while an estuary as a wide open area with slow water movement. So when the river flow reaches the estuary level the water just spreads out into the estuary at a much slower pace. Same volume of water just the difference of narrow and fast verses wide and slow. The river does not push through the estuary because there is not enough volume of water in that specific river.
I’m not a hydrologist, but I assume that is what is happening.
It’s flowing under the sand into the ocean …
There is also the possibility it enters into caves, or into a different sort of aquifer other than the sand dunes. (there might be porous rock.)
Also , these coastal lagoons can be very long, are you sure there is no actual waterway to the sea ? There migth be a man made canal carrying the flow.
This. I’m sure the river’s water is reaching the sea through a number of subsurface channels.
How large is the body of stagnant water? Especially how long measured parallel to the coast?
Waitasec.
I thought estuaries are ocean-to-ocean (not just oceans?) side burp things, and rivers are “non-ocean”-to-ocean things.
I’m having difficulty following.
ETA: Knowledgebase of Leo Bloom consists almost entirely of “the East River outside my window (NYC) is not a river but an estuary.”
I used to live in Missouri, karst country, with many underground caverns. I could follow a small stream for miles as it headed for the Meramec River. But before it got there, it ended in shallow pools where no water appeared to flow, but there always was inflow to the pools. I’m pretty sure it soaked into the ground, into caves, then came out on the other side of the hill in the river.
The upstream source of this river was another cave where someone had built a grotto over a spring. So the river came out of the ground then went back in a few miles later.
Leo: What is an estuary?
Estuaries are “river-ocean-interface” things. Estuary - Wikipedia
AIUI water extraction from rivers is a serious issue in some parts of the world. Isn’t the Aral Sea a poster-child for this?
I think you mean the former Aral Sea.
Thank you to Muffin and naita.
Carry on.
All right, wise guys, maybe I am the only one who had to look up “karst.” If so, I’m impressed (not unusual in observing knowledge of GQ posters…).
Then there’s the Okavango River:
…and as usual a US Federal Agency forgets there’s a whole karst in US Territory that happens to just not be in one of the &^%#~* 50. Sigh write to some Deputy Secretary again…
Are you saying that they didn’t karst their net far enough?
Maybe Puerto Rico was just tufa.
There’s no need to be snarky. PR shouldn’t have to put up with that schist.
Tufa.
Go ahead. You throw it, I’ll look it up.