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Would a salt flat be near a river?

I have a world with a Nile River-like region and within a few miles, perhaps 10-20, I have a massive salt flat. The arable land of the river brushes up against eastern edge of the salt flat but all the other "borders" are surrounded by a Sahara-like desert. Is this realistic?

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    $\begingroup$ Can it be a salt-water river? Tunisia's great Chott's (mega salt flats) drained saltwater rivers. $\endgroup$ – Mikey Jan 28 '16 at 0:41
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Salt flats are generally formed where ancient oceans, seas or even lakes have become cut off and water can only evaporate out of them. The Dead Sea is a current example, as is Great Salt Lake in Utah.

So sometime in the past, your river might have drained into a low lying area without access to the sea and the waters evaporated away, leaving the salt beds. At some more recent time in geological history, an earthquake or other geological change changed the course of the river, opening a channel to the sea.

Alternatively, the sea itself could have had an arm leading into the region which was cut off from the rest of the sea due to some geological event, eventually leaving great salt flats as the water evaporated away (which would be of greater extent and depth than those left by a more recent salt lake). The river's path could have moved closer to the salt flat over the ages, so its position today is a fortunate coincidence. A thousand years from now, the river could actually be running through the salt flat, washing the salt back into the sea.

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  • $\begingroup$ The salt flat is on the edge of a desert and is supposed to be an old dried lake. If I am understanding you correctly, it IS possible to have a river run next to a salt flat due to elevation or time changing water flow. Am I following? $\endgroup$ – Dynas Aug 29 '15 at 1:53
  • $\begingroup$ You are following perfectly. Great Salt lake in Utah is the remnants of Lake Bonneville, which drained out near the end of the last ice age. $\endgroup$ – Thucydides Aug 29 '15 at 12:45
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There are salt flat regions near the Nile itself. Perhaps the largest is the Qattara Depression.

The great bitter lake, now flooded with seawater as part of the Suez Canal, was once a salt flat. During the building of the Suez Canal, a small parallel canal called the Sweetwater Canal was built to supply fresh water to the area. The water came from the Nile via Lake Timsah.

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If the surface evaporation rate is high enough then yes, look at field salting in California, the river could supply the salt directly in a sandy environment or simply supply the moisture to wick salt from deeper deposits.

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As has been covered in other answers - salt flats are generally in depressions. This makes the situation where very slightly salty river water goes in, but never out, likely.

Whilst less likely, a salt and sulfur rich crater lake could have been made in a old caldera. Hot springs push the hot brine to the surface where they dried mostly before making it back to the nearby river. Doesn't quite fit your narrative though.

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