# A perennial river not breaking into the sea....why? **URL:** \ **Category:** Factual Questions\ **Created:** [April 23, 2017, 10:12am UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055 "2017-04-23T10:12:27Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![kambuckta](https://avatars.discourse-cdn.com/v4/letter/k/53a042/32.png) [@kambuckta](https://boards.straightdope.com/u/kambuckta)\ **Post date:** [April 23, 2017, 10:12am UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/1 "2017-04-23T10:12:27Z")
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? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [April 23, 2017, 11:11am UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/2 "2017-04-23T11:11:10Z")
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. ---
**Author:** ![davida03801](https://avatars.discourse-cdn.com/v4/letter/d/b5e925/32.png) [@davida03801](https://boards.straightdope.com/u/davida03801)\ **Post date:** [April 23, 2017, 11:30am UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/3 "2017-04-23T11:30:12Z")
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. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [April 23, 2017, 12:50pm UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/4 "2017-04-23T12:50:49Z")
It’s flowing under the sand into the ocean … ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [April 23, 2017, 2:21pm UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/5 "2017-04-23T14:21:45Z")
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. ---
**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\ **Post date:** [April 23, 2017, 2:37pm UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/6 "2017-04-23T14:37:05Z")
> [@watchwolf49](#): > > It’s flowing under the sand into the ocean … This. I’m sure the river’s water is reaching the sea through a number of subsurface channels. ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [April 23, 2017, 3:14pm UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/7 "2017-04-23T15:14:04Z")
> [@kambuckta](#): > > 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? How large is the body of stagnant water? Especially how long measured parallel to the coast? ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [April 23, 2017, 3:32pm UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/8 "2017-04-23T15:32:08Z")
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.” ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [April 23, 2017, 3:40pm UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/9 "2017-04-23T15:40:48Z")
> [@Isilder](#): > > 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.) 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. ---
**Author:** ![Muffin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/muffin/32/4341_2.png) [@Muffin](https://boards.straightdope.com/u/Muffin)\ **Post date:** [April 23, 2017, 3:46pm UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/10 "2017-04-23T15:46:17Z")
Leo: [What is an estuary?](http://oceanservice.noaa.gov/facts/estuary.html) ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [April 23, 2017, 4:38pm UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/11 "2017-04-23T16:38:39Z")
> [@Leo\_Bloom](#): > > 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.” Estuaries are “river-ocean-interface” things. [Estuary - Wikipedia](https://en.wikipedia.org/wiki/Estuary#Lagoon-type_or_bar-built) ---
**Author:** ![Quartz](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/quartz/32/267_2.png) [@Quartz](https://boards.straightdope.com/u/Quartz)\ **Post date:** [April 23, 2017, 5:02pm UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/12 "2017-04-23T17:02:28Z")
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? ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [April 23, 2017, 5:16pm UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/13 "2017-04-23T17:16:23Z")
> [@Quartz](#): > > 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. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [April 23, 2017, 5:16pm UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/14 "2017-04-23T17:16:34Z")
Thank you to **Muffin** and **naita**. Carry on. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [April 23, 2017, 5:21pm UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/15 "2017-04-23T17:21:21Z")
> [@Musicat](#): > > I used to live in Missouri, karst country, with many underground caverns. … 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…). [US Geological Survey everything-on-karsts page.](https://water.usgs.gov/ogw/karst/) ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [April 23, 2017, 9:41pm UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/16 "2017-04-23T21:41:55Z")
Then there’s the Okavango River: > [@](#): > > Discharging to an endorheic basin, the Okavango does not have an outlet to the sea. Instead, it empties into a swamp in the Kalahari Desert, known as the Okavango Delta or Okavango Alluvial Fan. ---
**Author:** ![JRDelirious](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jrdelirious/32/9531_2.png) [@JRDelirious](https://boards.straightdope.com/u/JRDelirious)\ **Post date:** [April 23, 2017, 10:55pm UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/17 "2017-04-23T22:55:51Z")
> [@Leo\_Bloom](#): > > 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…). > > [US Geological Survey everything-on-karsts page.](https://water.usgs.gov/ogw/karst/) …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… ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [April 23, 2017, 11:08pm UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/18 "2017-04-23T23:08:42Z")
> [@JRDelirious](#): > > …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 _tu_fa. ---
**Author:** ![friedo](https://avatars.discourse-cdn.com/v4/letter/f/8edcca/32.png) [@friedo](https://boards.straightdope.com/u/friedo)\ **Post date:** [April 24, 2017, 2:21am UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/19 "2017-04-24T02:21:03Z")
> [@Riemann](#): > > Are you saying that they didn’t karst their net far enough? > Maybe Puerto Rico was just _tu_fa. There’s no need to be snarky. PR shouldn’t have to put up with that schist. ---
**Author:** ![Leo\_Bloom](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/leo_bloom/32/10377_2.png) [@Leo\_Bloom](https://boards.straightdope.com/u/Leo_Bloom)\ **Post date:** [April 24, 2017, 2:56am UTC](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055/20 "2017-04-24T02:56:44Z")
[Tufa](https://en.wikipedia.org/wiki/Tufa). Go ahead. You throw it, I’ll look it up. [Next page](https://boards.straightdope.com/t/a-perennial-river-not-breaking-into-the-sea-why/785055.md?page=2)