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I'm curious if there are any saltwater rivers on Earth. These would presumably arise if a saltwater lake had a river outlet to the ocean.

However, all the saltwater lakes I looked at (Caspian Sea, Dead Sea, Great Salt Lake Utah), apparently don't have any river outlets.

Do any exist? And the obvious follow up, why or why not?

Edit: For the purposes of this question, undersea flows don't count. They are fascinating, but I'm interested if any "regular surface rivers" exist as saltwater rivers.

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    $\begingroup$ Well, if the saltwater lakes leaked water, they would get progressively less and less salty. To get a salty lake, you need a mechanism to increase the concentration of salt, which means more salt must be coming in than leaking out - which means most of the water must be lost through something that doesn't lose the salt as well; in the cases you mentioned, this is evaporation. However, there are salty marine currents, if you count those as "rivers" :) $\endgroup$ – Luaan Oct 3 '16 at 12:00
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    $\begingroup$ Define "saltwater". There are some fairly salty rivers in the western U.S., but none as salty as seawater. For instance, the Pecos River measures as high as 5,000 ppm in places, whereas seawater is 35,000 ppm. $\endgroup$ – hatchet - Reinstate Monica Oct 3 '16 at 18:00
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    $\begingroup$ @hatchet That's starting to sound more like it. For comparison, what is the salinity of a more "normal" river like the Mississippi or Nile? $\endgroup$ – DrZ214 Oct 4 '16 at 22:46
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    $\begingroup$ Midwest rivers would be in the 100 to <400 ppm. The Nile is 250 ppm at Aswan Dam (higher at the delta). This is according to various reports you can google up on the web. $\endgroup$ – hatchet - Reinstate Monica Oct 5 '16 at 0:10
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    $\begingroup$ @hatchet Okay I just looked up the Caspian Sea too, which says salinity 1.2% (1200 ppm?). If that's the case then definitely the Pecos River would count. However, you said "in places"? What places along the river are 5000 ppm? Is it like that for a majority of its length? $\endgroup$ – DrZ214 Oct 5 '16 at 1:12

18 Answers 18

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The water in any river draining the sea is infinitely recycle-able (from rain replenishment), whereas the salt from any terrestrial source is not. So salty rivers, if any, won't exist permanently. Saltwater lakes gain their salinity precisely because they have no outlet, so salt just gets concentrated by evaporation. I don't think there are any truly saline rivers throughout their entire length.

The nearest approximations I can think of are:

  • Rare ephemeral runoff from emergent salt domes in desert areas.
  • Freshwater rivers that drain into arid areas where combined evaporation and infiltration gradually reduces the flow to zero. These are more 'very brackish' than truly saline. The Amu Darya in Uzbekistan is one such example. I don't know the salinity of the Jordan as it enters the Dead Sea, but the river is reduced to almost nothing, whilst there are hypersaline springs, and sewage effluent from Amman draining into it.
  • The only river I can think of that is very highly mineralized from source to sea is only about 3 kilometres long. It is an unnamed river from the volcanic crater on Savo Island, in the Solomon Islands (Southwest Pacific). It is also acidic and boiling hot - quite literally, for most of it's length.
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    $\begingroup$ Great answer especially due to all those examples. Thanks. $\endgroup$ – DrZ214 Oct 3 '16 at 8:45
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    $\begingroup$ One more category of not properly a river would be tidal flows, which can be pretty strong and appear like rivers in some areas. $\endgroup$ – gerrit Oct 3 '16 at 10:39
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    $\begingroup$ Do the undersea saline flows like en.wikipedia.org/wiki/Black_Sea_undersea_river count? $\endgroup$ – Tim Brigham Oct 3 '16 at 14:35
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    $\begingroup$ @TimBrigham For the purposes of this question, they don't count. I'll make an edit to the OP. I'm interested in "regular surface rivers" only. $\endgroup$ – DrZ214 Oct 4 '16 at 22:42
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    $\begingroup$ This is a great answer, but I unaccepted it because there are so many other answers with at least one good example too. $\endgroup$ – DrZ214 Oct 6 '16 at 1:32
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The already accepted answer is already covering the "real" answer as far as I'm concerned, and while you won't find many (any?) saline rivers in the traditional sense, we do have underwater "rivers" that kiiiiind of but not quite fit the bill. They're not saline rivers as I expect you envision, but I figure they could be an interesting "by the way though" answer to the question anyway.

One good example is The Black Sea undersea river. The actual article in which it is originally posted seems to be unaccessible right now, so adding a more "prosaic" description of it:

It stems from salty water spilling through the Bosphorus Strait from the Mediterranean into the Black Sea, where the water has a lower salt content. This causes the dense water from the Mediterranean to flow like a river along the seabed, carving a channel and deep banks. 'It flows down the sea shelf and out into the abyssal plain much like a river on land,"

A 3-D radar image, using false color, of the undersea river channel where it enters the Black Sea from the Bosphorus Strait.

So much water flows through the Black Sea undersea river that it is estimated to possibly being the sixth largest river in the world.


Another, perhaps more visually impactful example might be the Cenote Angelita in Mexico, and although this isn't a river at all, it looks very much like one. The Cenote Angelita is a heavily saline mass of water found at the bottom of a fresh water cave, with a layer of Hydrogen Sulfate separating the two watermasses, snaking around in cracks and layers that make it look like a river. As far as I understand it, the waters here are essentially static and unmoving, which has caused the heavier saline water to sink to the bottom, while the fresh water lies on top. Essentially the same as when you put oil in a cup of water.

Cenote Angelita

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    $\begingroup$ According to other sources it's an HSO₄- (hydrogen sulfate, an aion) layer and not H₂S (hydrogen sulphide, a poisonous gas) $\endgroup$ – klanomath Oct 5 '16 at 7:54
  • $\begingroup$ Hum. Seems there's a lot of confusion on what it is, googling it around a bit i see some sources claim it's Sulfate, others it's sulphide. I can't imagine you would be wrong though, sulfate is a liquid and sulphide is a gas (at those temperatures), so I will amend the answer. Certainly seems overwhelmingly likely that sulfate is correct. $\endgroup$ – Kim André Kjelsberg Oct 5 '16 at 8:12
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    $\begingroup$ As a chemical oceanographer I can respond to the sulfate/sulfide debate. Stagnant high-salinity (dense) bottom water loses sulfate (normally 0.028 molar, or 8% by weight of sea salt) to sulfate-reducing bacteria, who want its oxygen. The reaction is H2SO4 -> 2 O2 + H2S (although the actual mechanism is much more complicated). This means that below ~200 m the Black Sea is poisonous to everything but anoxic bacteria. See Oxic, Suboxic and Anoxic Conditions in the Black Sea for oceanography. $\endgroup$ – becula Oct 8 '16 at 10:29
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    $\begingroup$ This place looks surreal... thanks for posting!! $\endgroup$ – Mehrdad Oct 8 '16 at 23:07
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The Pecos River in Texas, USA may arguably fit the description of a "saltwater river". A point of argument is what is considered to be "saltwater". For comparison, here are some bodies of water and their salinity.

  • 35,000 ppm Pacific and Atlantic Ocean
  • 13,000-23,000 ppm Black Sea
  • 12,500 ppm Caspian Sea
  • 10,000 ppm Baltic Sea

Note though, that salinity varies based on where, and at what depth you measure it. For example, the Baltic Sea has salinity as low as 5,000 to 8,000 ppm at the surface of the central basin.

At its saltiest, the Pecos River is reaching the lower end of the range above. Different sources give different threshold between the definitions of freshwater, brackish water, and saline water. Most would probably deem the Pecos as brackish (which would describe the Baltic Sea by the same standard), but it is salty enough to be a problem for human use. There are a number of sources that discuss the issue of the Pecos River and its salinity, but I'll direct you to this one, and quote a little from it

The Pecos River is among the saltiest rivers in North America with salinity levels regularly exceeding 7,000 ppm at the Texas and New Mexico border and 12,000 ppm near Girvin, Texas. High salinity in the river has adversely affected the stability and biodiversity of the riparian ecosystems, as well as, the economic uses of the river and reservoirs.

In general, natural sources of salt throughout the watershed cause the Pecos to be salty.

If you look at the slides in this presentation you'll see that different measurement locations range from around 1,000 ppm to 12,000 ppm (it gives measurements in mg/l, but that is roughly equivalent to ppm). It also gives historical measurement graphs for some select stations. The presentation also highlights that there is a history of efforts to engineer a reduction of the river's salinity.

The source of the Pecos River's saltiness is not so much surface salt as it is subsurface sources in the form of saline aquifers that feed the river through salt springs, for example. This research paper suggests that although the Pecos was naturally salty, the activities of man have increased the salinity. The major activity is irrigation, through two mechanisms. One is the diversion of water for irrigation, which allows increased evaporation in the fields, and irrigation water that returns to the river with more concentrated salt content. The other is the depletion of freshwater aquifers through pumping. The Pecos watershed overlays both saline and freshwater aquifers, both of which have historically contributed to the riverflow. Man has ignored the saline aquifers, but heavily pumped the freshwater aquifers, reducing their contribution to the river, but not the contribution of the saline aquifers.

This report is also good, and goes into much detail about the sources, both natural and human, of the Pecos River's salinity.

The upper reaches of the Red River in Texas overlay the same formation that creates saline conditions in the Pecos River. The streams and springs that form the source of the Red River are quite salty, and it is only further downstream, after dilution from other freshwater inputs that the Red River loses its high salinity. As this USGS fact sheet says:

Salinity is the greatest limitation on water use in the Red River Basin and is largely the result of naturally occurring salt springs in parts of the upper reaches of the basin (Keller and others, 1988). The salt sources contribute water with large (relative to potable water) concentrations of dissolved solids, principally chloride. At certain times and locations, the salinity of streams in the basin exceeds that of seawater (Keller and others, 1988).

Salty bed of Little Red River, a tributary of Red River, Texas (Wikipedia)

Salty bed of Little Red River, a tributary of Red River, Texas (Wikipedia)

There are salty rivers in various places on Earth, but they are primarily found in arid regions. Since much of their flow comes from groundwater (which may be much saltier than rainfall), and evaporation from the river surface is high, it seems reasonable to me that they would be more likely to be saltier than rivers in wet regions that have large contributions from rainfall, and less net evaporation. These factors are magnified by human activities such as irrigation which happens in arid regions, but less so in areas of ample rainfal.

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    $\begingroup$ Thanks. natural sources of salt throughout the watershed cause the Pecos to be salty. Can you elaborate on this because it seems to be an antidote or counterexample as to why saltyrivers hardly exist. Maybe a good follow up question is why surface salt seems to be so rare or just doesnt wash into rivers via their watersheds for some reason. $\endgroup$ – DrZ214 Oct 6 '16 at 1:35
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    $\begingroup$ @DrZ214 - I've added some additional information that may at least partially address the points in your comment. I added another source which I've summarized, although it may understate the salinity of the river prior to human development, as it provides little more than slim anecdotal evidence to support that point. Nevertheless, the case that irrigation can increase river salinity is hard to dispute. $\endgroup$ – hatchet - Reinstate Monica Oct 6 '16 at 19:50
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Water from the Caspian sea, with a salinity of 1.2%, is constantly flowing into Garabogazköl, where the water eventually evaporates and leaves the salt behind. Of course, the situation is not indefinitely stable, as the depression is eventually going to be filled with salt. But at the time writing, water is still flowing like a river through the very narrow inlet:

Garabogazköl

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Here in New York City we have a salt "river". It is called the "East River" and it separates part of Long Island (Brooklyn and Queens) from the island of Manhattan and the mainland (The Bronx).

Indeed it looks a lot like a salt river:

East River

From a hydrology perspective it is not a river tho, it is actually a saltwater estuary.

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  • $\begingroup$ The East River isn't even a "river", its just called that, because it connects to the ocean at both ends. Other tidal estuaries such as Chesapeake Bay are better candidates, because they actually have a river at one end. $\endgroup$ – Spencer Nov 16 at 23:48
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I live near a river named Salz, flowing both warm and salty on the north slope of the Pyrenees south of Carcassonne. In historical times it was boiled dry for salt. See Les Sources de Salz

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There are salt water rivers in different places of the world where ground water flows in contact with salt layers.

There is a river in Catalonia named Ribera Salada (meaning salty river in Catalan). My translation from Catalan Wikipedia:

It gets its name because one of its originating currents - Fred river - comes from sources in Triassic lands with a high content of salts. The river is salty enough that its waters had been used for long time in Cambrils to obtain salt.

However, Ribera Salada is actually salty just in part of its course, since mixing with other freshwater currents makes it brackish or nearly freshwater.

Ribera Salada in Castellar de la Ribera. Image from Wikimedia Commons. Credits here.

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Here in Western Australia we have many salt water streams running through farmland affected by dry land salinity. It's a huge problem where land cleared for agriculture has experienced rising water tables effectively bringing salt to the surface. This salt is washed into the creeks by rain and these streams are essentially salt saturated - far saltier than seawater. The streams generally only flow during winter though. Huge tracts of land are no longer arable because of the extreme salinity.

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  • $\begingroup$ Interesting. Are you saying that clearing land leads to rising water tables? Why would that be? $\endgroup$ – AllInOne Oct 7 '16 at 16:15
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    $\begingroup$ The trees that previously occupied the land consumed vast amounts of groundwater. With the imbalance of ingress vs consumption with many millions of trees cleared, the water table rose. It's a well documented situation here in Western Australia and also South Australia. To be honest I assumed it'd be a world-wide issue but I guess it's not. Our wheat farms are typically on a very large scale (like 10000 acres or more for the larger ones) and when these areas were initially cleared they were virtually completely stripped of all trees in huge tracts. We now have millions of acres of bare land. $\endgroup$ – cogsy Oct 8 '16 at 4:21
  • $\begingroup$ Wellington Dam, in south west Western Australia, used to be a fresh water dam when first constructed in 1933, but since 1990 it has been abandoned as a fresh water source due to salinity levels arising from dry land salinity. $\endgroup$ – Fred Nov 12 at 17:18
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There is an area with several salt rivers and wide salt streams that exists in Russia - it's in Yakutia (Sakha Republic), part of Siberia.

Water of Solyanka River (flowing in to the great Lena River) contains 21 g of salt per liter, some neighboring streams can contain up to 70 g of salt per liter of their water...

According to science, millions years ago this territory was covered by a large sea. Later, due to uplift of the crust it was divided into many salt lakes in numerous cavities. And after the water has dried up - large stratum of salt remained inside the earth. So modern rivers and streams flowing through this stratum are fully saturated with salt.

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    $\begingroup$ Could you add some references please? $\endgroup$ – L.B. Oct 5 '16 at 19:53
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    $\begingroup$ I would like to read more about River Solyanka too. The wiki aticles (in both english and russian) dont mention its salinity. $\endgroup$ – DrZ214 Oct 6 '16 at 1:37
  • $\begingroup$ @DrZ214 Solyanka's salinity would range somewhere betweem 5000 and 10000 ppm, depending on the cook. $\endgroup$ – the-wabbit Oct 6 '16 at 7:16
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    $\begingroup$ @L.B. Unfortunately I can't find any good English language reference about this, only in russian. It's hard to find source of something in Internet but all russian references to this story presents it as 'well known fact'. $\endgroup$ – Sergey Oct 6 '16 at 16:22
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    $\begingroup$ @Sergey I see. Could you add one or two of the Russian references? Then if someone wants to read about it they could use a translator. :) $\endgroup$ – L.B. Oct 6 '16 at 18:45
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The Werra – a natural river – had and up to a certain degree still has at least a brackish water body. A portion of the salt content of the river comes from natural leaching, the greater part is passed by nearby potash industry.

Heringen (Heringen with the Werra between mine and city. The picture was shot from the Monte Kali)

The legal threshold value in the 1940s was a salinity of about 0.5%. The value was often exceeded. Later in the 1960's the underground dumping of the by-products was ceased and all the brine ended in the Werra. The salinity rose up to 4.0%.

The ocean like salinity terminated the former (almost) freshwater habitat and changed it to brackish water habitat with a very low biodiversity: e.g. only one invertebrate (of former 60 -100) survived and two invertebrate halophile aliens were introduced.

After the German reunification potash mining (a lot of mines were in the former GDR) declined and stricter limits were introduced. The salinity limits now are ~0.5 % and will be reduced to ~0.3% until 2019. The actual salinity seems to be ~0.33% (Source: Werra-Versalzung Gutachten p44/45).

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Beyond the answers above, here is a small river near Berca, Romania, where active mud volcanism and salt diapirism are widespread, explaining the high salinity of this water.

my own pictureSalty river. Note box for scale. (My own picture, geotagged)

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Here in Norway we are mighty proud of "Saltstraumen"(meaning Salt Stream)

Again, not technically a river, but a narrow strait connecting the ocean to a wider fjord behind it.

As the tides go in and out, Saltstraumen does too. It is the world's strongest tidal current.

Wikipedia link.

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There is also a hypersaline periodic water flow, which although a few times more saline than sea water, I might be hesitant to call a river. However, due to its high salinity (well above everything else mentioned here), I thought it was worth mentioning.

It is called Blood Falls. It is the periodic draining of a brine reservoir under the Tylor glacier in the Dry Valleys of Antarctica.

blood falls

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    $\begingroup$ @Imtherealsanic Thanks for the edits. It is much appreciated and help me to learn too :-) $\endgroup$ – Camilo Rada Feb 26 '18 at 0:08
  • $\begingroup$ No problem! Anything for the benefit of another! :D $\endgroup$ – Eevee Feb 26 '18 at 0:09
  • $\begingroup$ Tried to make additional improvements. Note that you link to the Dry Valleys file appears to have been a local link on your hard drive and not a web link? I changed it to Wikipedia for the time being. Thanks for good/interesting answer :-) $\endgroup$ – JeopardyTempest Feb 26 '18 at 6:23
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Świna (note that while english wikipedia lists it as a river, both german and polish wikipedias are more ambiguous, for example polis wiki descirbes it as a "strait" of the Baltic sea): Świna (Wikipedia).

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There are specific rivers that sometimes flow inward called Tidal Bores.

A great example of a Tidal Bore is the Amazon River.

pororoca

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From my country there is indeed a saltwater river in the north western state of Rajasthan - Luni river. It is not salty from the point of it's origin but does become salty as it flows downstream.

Here is a more complete description of the Luni river -

Luni River basin facts.

Looking at this book - Contributions to the ecology of halophytes one wonders on the accumulation of salt in these arid basins. Considering the basin is in proximity to the Great Rann of Kutch there were earlier conjectures that the atmosphere carried the salts as either particles or sprays of sea water. Wider acceptance of the origin of salt these days is due to the atmospheric decomposition of feldspathic rocks and leaching by rain water.

It is probably the only river of consequence in the Western part of Rajasthan which forms part of the Thar desert

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NOTE: Okay, I'm trying again to answer this question. I'll make sure to back it up with accurate information this time :)

There is a river in Arizona called the Salt River. In the article linked, it states the river is 'special' because It's salty.

There are known to be more than just the Salt River; but there's an example of a saltwater river for you :)

If you're still questioning my response, please read the article liked for more information.

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    $\begingroup$ Not bad. You are making progress. Hope you forget the reputation part and just focus on content as many have advised $\endgroup$ – gansub Feb 26 '18 at 16:25
  • $\begingroup$ @gansub I don't just create good posts just for the reputation, I post them for the benefit of others willing to learn from them. Although I do try to keep my reputation from falling as much as I possibly could. $\endgroup$ – Eevee Feb 26 '18 at 20:40
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There is a saltwater River in India called Luni river Luni (also known as Lonari, Lavanavari, Lavanavati, Salt river) is a river in Rajasthan. It originates in the Pushkar valley of the Aravalli Range, near Ajmer, passes through the southeastern portion of the Thar Desert, and ends in the marshy lands of Rann of Kutch in Gujarat, after travelling a distance of 495 km.

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    $\begingroup$ Already covered it in my answer about Luni $\endgroup$ – gansub Nov 11 at 6:48

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