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Comment by ChuckMcM | Hacker News Reader

The California aqueduct (444 miles, 714km) would like to have a word :-).

Basically built for the same reason, the central valley of California was mostly arid but the top soil was good for agriculture. The underground aquifer was a limit on how much farming (and of what type) could be done.

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There are indeed several man-made rivers longer then this so it's unclear what the editors were thinking with this headline.

The longest one that I know of is the Grand Canal in China, which begain construction approx. 1400 years ago. https://en.wikipedia.org/wiki/Grand_Canal_(China)

Whilst it could be that the editor or author are technically wrong it’s also quite possible that they might be technically correct and were just arguing semantics here.

As far as geography/geology/hydrology goes rivers have a specific definition which the grand canal might not fit especially as one big system since afaik it extends and connects to multiple rivers and the water doesn’t flow in a single direction into a larger body of water.

Each contiguous part of the Grand Canal only flows in one direction, it would be impossible for it to work otherwise.

You do have a point though that this new river in Egypt may be the 'largest' on some other metric.

The issue isn’t direction but rather having multiple branches as a river only includes channel(s) going downstream from a single point. Without that definition a river’s length would be the length of every river connected to it.

Thus the Mississippi and Ohio river are considered different rivers even though their waters mix and both flow downstream through the same channel.

https://en.wikipedia.org/wiki/Ohio_River, https://en.wikipedia.org/wiki/Mississippi_River

According to this definition then Iraq’s man-made river (Saddam’s river) is longer at 565 km. the official role of the river was to collect irrigation water from Mesopotamia fertile land all the way to the Persian Gulf, though the real reason Saddam built it was to dry the Arab Marshes as it was difficult to contain the rebels in the marshes. https://ar.wikipedia.org/wiki/%D8%A7%D9%84%D9%85%D8%B5%D8%A8...

I thought most of that 565km distance was an existing waterway.

In English: https://en.wikipedia.org/wiki/Draining_of_the_Mesopotamian_M...

I think the distinction the authors are making - correctly or not, I’m not sure, plenty of rivers don’t flow to the sea - is this artificial river flows into the sea, not into other canals or rivers.

The grand canal connects the Yellow and Yangtze rivers, for example.

Maybe it is by total volume or flow rate

I don't think a canal that's split by locks would qualify as a river that's running in one direction all the way

I don't think locks are the reason it wouldn't count. Otherwise the Thames would end at Teddington.

So you're saying these Egyptians are in de nile?

Sarcasm like this is technically against HN policy but this made my day. Thanks for the laugh.

That is not sarcasm. Not all jokes are sarcasm.

I have been to the cloak room and got your coat.

Lines like that are best kept in your Dad-a-base.

>There are indeed several man-made rivers longer then this so it's unclear what the editors were thinking with this headline.

There's one underground that's even longer: https://en.wikipedia.org/wiki/Delaware_Aqueduct

Currently China is building a new project: https://en.wikipedia.org/wiki/South%E2%80%93North_Water_Tran... which I believe is larger.

An aqueduct isn’t a river. While the exact definition may seem vague the use of multiple pumping stations along the Californi aqueduct are one obvious difference.

Ex: https://en.wikipedia.org/wiki/Edmonston_Pumping_Plant, https://en.wikipedia.org/wiki/Dos_Amigos_Pumping_Plant, etc.

It's unclear that the river in the article is a river in the conventional sense, either: it seems to be routed underground for long stretches of tunnel at points.

(The longest tunnel in the world is also a water tunnel, and supplies NYC with water[1].)

[1]: https://en.wikipedia.org/wiki/Delaware_Aqueduct

Natural rivers will sometimes flow underground: https://en.wikipedia.org/wiki/Subterranean_river

The Erie Canal (362.9 mi) is not as long as the California aqueduct nor the Grand Canal in China but it is also longer than the "man made river" of the article, and IT HAS A SONG, and a good one at that.

Libya's Great Man-Made River (1,750mi, 2,820km) [0] would like to have a few more words :-). [0] https://en.m.wikipedia.org/wiki/Great_Man-Made_River

Let's nitpick then. It says: "According to its website, it is the largest underground network of pipes (2,820 kilometres (1,750 mi))[3] and aqueducts in the world.".

It could concievably have no pipe longer than 114 km.

Also if it's underground it's not a river?

https://en.wikipedia.org/wiki/Subterranean_river

That's a heck of an aquifer. Libya is pumping 2.4 km^3 a year from the estimated 150,000 km^3 reserve.

This will act like a river as it does flow into the med and will create a new delta (hence the name).

Even the Romans (Byzantine if you wish) built the aqueduct of Valens supplying Constantinopole with fresh water over 426km so yeah I'm also not sure what is this so impressive. And anyway, if the Egyptian one stays uncovered as the pictures show it, I wonder how much water will it have left on a hot day (which are almost all) when it approaches destination.

Doesn't California also contain the largest earthen dam or something to that extent? It's not as impressive as the Hoover dam or the Three Gorges dam but it's still huge from what I understand.

Largest in the US at least.

Fairly recently it decided to shorten it's own spillway a bit though. Shortly afterwards it gained a whole lot of concrete.

Juan Brown has a very comprehensive series on that excitement[0]

[0]https://www.youtube.com/watch?v=Wikin2TJ7b0&list=PL6SYmp3qb3...

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