Talk:List of rivers by length

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	List of rivers by length is a former featured list candidate. Please view the link under Article Milestones below to see why the nomination failed. Once the objections have been addressed you may resubmit the article for featured list status.
Article Milestones Date Process Result June 20, 2005 Peer review Reviewed June 26, 2005 Featured list candidate Not promoted February 27, 2007 Featured list candidate Not promoted Current Status: Former featured list candidate

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My goal is to create lists of rivers sorted by different characteristics of the rivers. As example, I am using the lists of countries, also sorted by different characteristics. I also want to add tables with these data to all rivers, containing information of ranking as well as the data themselves. Unresolved issue: should tribituaries be included? Gerritholl 08:45, 23 Aug 2004 (UTC)

For drainage area, it doesn't make that much sense, because the area always applies to a whole river system. But for other characteristics, such as length, tributaries should be included. Chl 02:23, 13 Nov 2004 (UTC)

Contents 1 Sorting of table doesn't work properly 2 Longest river 3 Centering 4 Definition of length 5 Removed information / missing rivers 6 re: historical Amazon drainage 7 Length of Yellow River 8 Historical rivers 9 Evaporating 10 Discrepancies

[edit] Sorting of table doesn't work properly

Sorting the table by discharge yields 63,166 (Purus) > 6,915,000 (Amazon). Obviously, the software has problems with the commas. By the way, is this sorting feature a dedicated Wikipedia software? 14:59 (UT), 24 Mar 2007

[edit] Longest river

The Nile article states that it in fact is the longest, I think it would be better if this list actually reflected the respective articles. Phoenix2 03:08, 20 Jun 2005 (UTC)

[edit] Centering

In response to Cburnett's edit summary, "Revert: *exactly* what looks off-center?", the central table listing the color key for the continents (which was the entire point of the exercise). Placing that table and the two images into a larger table, per your edit, creates three cells, and the central cell is centered. The problem, though, is that the continent table is still left-aligned within its cell; at high resolution, this becomes quite jarring. Compare its placement to the centered text immediately above it. The proper solution is to add centering to the continent table's style. --Cryptic (talk) 00:30, 22 Jun 2005 (UTC)

Thanks for the information and the new continent colour key. Phoenix2 17:22, 22 Jun 2005 (UTC)

[edit] Definition of length

This section should be a separate page, since the issues apply to rivers of any length, not just the longest. It's also just a list of questions with no answers beyond "it's hard/impossible". If it's hard, what's the solution? If it's impossible, what are the workarounds? Does the National Geographic or the like have a list and, if so, what methodology did they use?

• multiple sources: the Mississippi-Missouri point is not about how it's hard to determine length, it's about how the channel may not have a single name throughout its length. This makes no difference to the calculations; just use the longest channel, as stated
• seasonal changes: as per multiple sources, longest is surely the rule here?
• I don't think fractal dimension applies to mid-channel measurement. Does anyone use bank measurement? Which of the two banks?
• multiple arms: as per multiple tributaries.
• length through a lake: What are the options? straight line/deepest channel/ current flow? Can somebody find out?

According to the 1983 Edition of the Guinness Book of Records, the Nile-Amazon controversy does not refer to the vague general points in the section, but specifically to whether to include the Tocantins River estuary south of Marajó as part of the length of the Amazon. Most geographers say no, because the water flows from the Tocantins into the Amazon and not vice-versa. The "Some believe a fair statement is that the Nile is the longest in the world, while the Amazon is the strongest." comment suggests the dispute is motivated by chauvinism more than science. Joestynes 4 July 2005 10:23 (UTC)

OK, you are addressing a whole bunch of issues here... Let's see...

1) Methodology used by other publications such as NG. I have never seen a source that uses a single, well-defined methodology. Everyone uses different primary sources for rivers from different parts of the world, and each source uses a slightly different methodology. For a lot of rivers there aren't any measurements available, only estimates.

2) Mississippi-Missouri. You are right that measuring the length of a river and defining which source to measure from are really two different issues, but this is getting a bit subtle. Most encyclopedias don't even bother to explain what the difference between the Mississippi and the Mississippi-Missouri is, and why one would want to consider the M-M instead of the Mississippi. It would be great if we can find a wording to make it clearer.

3) The discussion about fractal properties is somewhat misleading. All it means is that you need to get maps that are precise enough. If you have a map that is precise enough, a river is *not* fractal, because you measure in the middle of the river. It would be fractal if you chose to measure along the banks, but why would you do that?

4) Multiple arms and measuring through lakes: What is usually done is to measure the shortest distance from source to mouth. The reason is that otherwise, one can arbitrarily increase the length of a river, as your Amazon/Tocantins example shows. If a river has an island, one could even do a few loops around the island while measuring if one wants to maximize the length... ;) For lakes, this means that the shortest line from inflow to outflow that does not leave the lake should be measured. IOW, it's the shortest route you can take in a boat (assuming the river is navigable). Considering things like depth and current is rather unpractical because those are not known in most places.

5) Nile versus Amazon: sure, there is always chauvinism involved. But there have been new data from the Amazon since 1983, supposedly its headstreams are longer than previously thought. I don't have details though. That does not change the fact that, no matter which mouth you look at, there is no definite point where the Amazon ends. There is necessarily some arbitrariness involved in deciding where the estuary ends and where the ocean starts.

--Chl 4 July 2005 16:17 (UTC)

[edit] Removed information / missing rivers

If one compares the article with the version from May [1], two things are noticeable:

• It looks much prettier now. The table format seems well-designed and useful. That's good.
• A lot of information was removed. The list used to have about 150 rivers and has about 40 rivers now. That's not good.

I understand that it's a lot of work to prettify a list like this, but I don't think it should be a reason to remove information. I would suggest to add the old information back in the old format even if it's ugly, and then gradually adapt it to the pretty format.

Missing rivers: the current list, which goes down to 2000 km, is missing several rivers that are over 2000 km and were in the old version, e.g. the Lower Tunguska or the Red River (Mississippi watershed). I am not sure what happened here.

Comments? --Chl 4 July 2005 16:55 (UTC)

Missing river: I believe the Australian River, Cooper Creek/Barcoo River with the tributaries Alice and Thompson Rivers should be added to the list of rivers greater than 1000 km in length. The overall length is approximately 1400 km. The Barcoo rises in Central Queensland, and flows to Lake Eyre. When it joins the Thompson River, it becomes Cooper Creek.

Comments? --Parminter 18 April 2006 09:50 (UTC)

Added that and the Georgina. Kmusser 21:01, 28 April 2006 (UTC)

[edit] re: historical Amazon drainage

"The Amazon basin formerly drained westwards into the Pacific Ocean, until the Andes rose and reversed the drainage." Is this so? I thought that the basin had drained into the (proto-)Carribean before the rising northernmost portion of the Andes blocked that route... I'm not 100% sure of that though. Herostratus 01:06, 28 May 2006 (UTC)

[edit] Length of Yellow River

There are two versions of the length of yellow river, 4350 km and 5500 km. Majority of the sources I can find (including Encyclopaedia Britannica) put length of Yellow River to be 5464 km, which means 6th longest river. Shall we change the number to 5464 or at least put this different aspect under the Notes. Wang ty87916 00:31, 24 August 2006 (UTC)

[edit] Historical rivers

I don't understand the section about "longest rivers that probably existed in the past." The title alone is a clue that there might be something wrong here. I am tempted to just remove it. Thoughts? --Dmz5 04:11, 9 December 2006 (UTC)

[edit] Evaporating

Does a river literally evaporate in the dictionary sense of the word? I don't understand this reference. I understand the concept that the river does not reach a body of water, but what actually happens to said river?--Dmz5 05:30, 9 December 2006 (UTC)

In some cases, yes. The already low river volume is slowly reduced wetting the river sediments. Evaporation from the water surface and the sediments ensures that the water flows no farther. In some cases some water will be sinking into the aquifer but we can say that the last of the water in the river is the water trapped in the surface sediments and evaporating, so evaporating is correct. In other cases, the last of the water is diverted for agriculture. For examples, see Rio Grande, Colorado River, Darling River. An odder one is the Okavango River which simply ends in an inland delta. Rmhermen 05:54, 9 December 2006 (UTC)

Thanks! I know this isn't the topic of this article, but I was confused by that statement. If nobody minds I'm going to add some of that explanation to the article.--Dmz5 07:03, 9 December 2006 (UTC)

Completely evaporating is actually fairly common for intermittent rivers in drier areas, there are at least a couple on the list - I think the Shebelle is probably the longest that ends this way without major diversions for agriculture. Intermittent rivers really ought to have its own article. Kmusser 17:08, 9 December 2006 (UTC)

[edit] Discrepancies

The lengths for the world's longest rivers differ considerbly in different Wikipedia articles. The longest rivers list in the River entry also differs from the List of rivers by length entry. AreDaval 02:58, 4 January 2007 (UTC)