What is the steepest gradient that a canal can be traversable without locks? The 2019 Stack...

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What is the steepest gradient that a canal can be traversable without locks?



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For a civilization that depends heavily on canals for transportation, what limits are there on how steep canals can before they flow too fast to traverse? I know that barges were normally pulled by animals upriver, if winds were unfavorable, so would the maximum slope of the canal depend on how strong the beasts of burden are? It would be neat to be able to calculate the slope in like meters dropped per kilometer in a general sense.










share|improve this question











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  • 14




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    Going downstream, you could go all the way to 90 degrees if you wanted to. White water rafting with cargo.
    $endgroup$
    – Tim B II
    2 days ago






  • 13




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    You can be the first on the pulleys to lift the barge back up the cliff.
    $endgroup$
    – GiruŠatuku
    2 days ago






  • 10




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    It isn't having to go uphill that would be the problem. The real problem would be the speed of the water rushing downhill. As soon as that speed gets anywhere near the speed of your boat, your're not going to go anywhere. And it doesn't take much of an angle to make water flow quickly. If you can notice a slope, you're not going to be sailing up it. The Mississippi is long and navigable, and it rises only .12m per kilometre. That's .012%. The purpose of locks is to eliminate the slope.
    $endgroup$
    – Ray Butterworth
    2 days ago






  • 3




    $begingroup$
    This seems to be what you want : lmnoeng.com/Channels/trapezoid.php
    $endgroup$
    – Ville Niemi
    yesterday






  • 24




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    The problem is never how hard it is to pull barges upstream, the problem is always how to keep the canal filled with water. If the canal has any amount of appreciable slope water will flow downhill. Where does the water come from?
    $endgroup$
    – AlexP
    yesterday


















15












$begingroup$


For a civilization that depends heavily on canals for transportation, what limits are there on how steep canals can before they flow too fast to traverse? I know that barges were normally pulled by animals upriver, if winds were unfavorable, so would the maximum slope of the canal depend on how strong the beasts of burden are? It would be neat to be able to calculate the slope in like meters dropped per kilometer in a general sense.










share|improve this question











$endgroup$








  • 14




    $begingroup$
    Going downstream, you could go all the way to 90 degrees if you wanted to. White water rafting with cargo.
    $endgroup$
    – Tim B II
    2 days ago






  • 13




    $begingroup$
    You can be the first on the pulleys to lift the barge back up the cliff.
    $endgroup$
    – GiruŠatuku
    2 days ago






  • 10




    $begingroup$
    It isn't having to go uphill that would be the problem. The real problem would be the speed of the water rushing downhill. As soon as that speed gets anywhere near the speed of your boat, your're not going to go anywhere. And it doesn't take much of an angle to make water flow quickly. If you can notice a slope, you're not going to be sailing up it. The Mississippi is long and navigable, and it rises only .12m per kilometre. That's .012%. The purpose of locks is to eliminate the slope.
    $endgroup$
    – Ray Butterworth
    2 days ago






  • 3




    $begingroup$
    This seems to be what you want : lmnoeng.com/Channels/trapezoid.php
    $endgroup$
    – Ville Niemi
    yesterday






  • 24




    $begingroup$
    The problem is never how hard it is to pull barges upstream, the problem is always how to keep the canal filled with water. If the canal has any amount of appreciable slope water will flow downhill. Where does the water come from?
    $endgroup$
    – AlexP
    yesterday
















15












15








15


1



$begingroup$


For a civilization that depends heavily on canals for transportation, what limits are there on how steep canals can before they flow too fast to traverse? I know that barges were normally pulled by animals upriver, if winds were unfavorable, so would the maximum slope of the canal depend on how strong the beasts of burden are? It would be neat to be able to calculate the slope in like meters dropped per kilometer in a general sense.










share|improve this question











$endgroup$




For a civilization that depends heavily on canals for transportation, what limits are there on how steep canals can before they flow too fast to traverse? I know that barges were normally pulled by animals upriver, if winds were unfavorable, so would the maximum slope of the canal depend on how strong the beasts of burden are? It would be neat to be able to calculate the slope in like meters dropped per kilometer in a general sense.







transportation rivers






share|improve this question















share|improve this question













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share|improve this question








edited 18 hours ago









smci

1798




1798










asked 2 days ago









GiruŠatukuGiruŠatuku

12219




12219








  • 14




    $begingroup$
    Going downstream, you could go all the way to 90 degrees if you wanted to. White water rafting with cargo.
    $endgroup$
    – Tim B II
    2 days ago






  • 13




    $begingroup$
    You can be the first on the pulleys to lift the barge back up the cliff.
    $endgroup$
    – GiruŠatuku
    2 days ago






  • 10




    $begingroup$
    It isn't having to go uphill that would be the problem. The real problem would be the speed of the water rushing downhill. As soon as that speed gets anywhere near the speed of your boat, your're not going to go anywhere. And it doesn't take much of an angle to make water flow quickly. If you can notice a slope, you're not going to be sailing up it. The Mississippi is long and navigable, and it rises only .12m per kilometre. That's .012%. The purpose of locks is to eliminate the slope.
    $endgroup$
    – Ray Butterworth
    2 days ago






  • 3




    $begingroup$
    This seems to be what you want : lmnoeng.com/Channels/trapezoid.php
    $endgroup$
    – Ville Niemi
    yesterday






  • 24




    $begingroup$
    The problem is never how hard it is to pull barges upstream, the problem is always how to keep the canal filled with water. If the canal has any amount of appreciable slope water will flow downhill. Where does the water come from?
    $endgroup$
    – AlexP
    yesterday
















  • 14




    $begingroup$
    Going downstream, you could go all the way to 90 degrees if you wanted to. White water rafting with cargo.
    $endgroup$
    – Tim B II
    2 days ago






  • 13




    $begingroup$
    You can be the first on the pulleys to lift the barge back up the cliff.
    $endgroup$
    – GiruŠatuku
    2 days ago






  • 10




    $begingroup$
    It isn't having to go uphill that would be the problem. The real problem would be the speed of the water rushing downhill. As soon as that speed gets anywhere near the speed of your boat, your're not going to go anywhere. And it doesn't take much of an angle to make water flow quickly. If you can notice a slope, you're not going to be sailing up it. The Mississippi is long and navigable, and it rises only .12m per kilometre. That's .012%. The purpose of locks is to eliminate the slope.
    $endgroup$
    – Ray Butterworth
    2 days ago






  • 3




    $begingroup$
    This seems to be what you want : lmnoeng.com/Channels/trapezoid.php
    $endgroup$
    – Ville Niemi
    yesterday






  • 24




    $begingroup$
    The problem is never how hard it is to pull barges upstream, the problem is always how to keep the canal filled with water. If the canal has any amount of appreciable slope water will flow downhill. Where does the water come from?
    $endgroup$
    – AlexP
    yesterday










14




14




$begingroup$
Going downstream, you could go all the way to 90 degrees if you wanted to. White water rafting with cargo.
$endgroup$
– Tim B II
2 days ago




$begingroup$
Going downstream, you could go all the way to 90 degrees if you wanted to. White water rafting with cargo.
$endgroup$
– Tim B II
2 days ago




13




13




$begingroup$
You can be the first on the pulleys to lift the barge back up the cliff.
$endgroup$
– GiruŠatuku
2 days ago




$begingroup$
You can be the first on the pulleys to lift the barge back up the cliff.
$endgroup$
– GiruŠatuku
2 days ago




10




10




$begingroup$
It isn't having to go uphill that would be the problem. The real problem would be the speed of the water rushing downhill. As soon as that speed gets anywhere near the speed of your boat, your're not going to go anywhere. And it doesn't take much of an angle to make water flow quickly. If you can notice a slope, you're not going to be sailing up it. The Mississippi is long and navigable, and it rises only .12m per kilometre. That's .012%. The purpose of locks is to eliminate the slope.
$endgroup$
– Ray Butterworth
2 days ago




$begingroup$
It isn't having to go uphill that would be the problem. The real problem would be the speed of the water rushing downhill. As soon as that speed gets anywhere near the speed of your boat, your're not going to go anywhere. And it doesn't take much of an angle to make water flow quickly. If you can notice a slope, you're not going to be sailing up it. The Mississippi is long and navigable, and it rises only .12m per kilometre. That's .012%. The purpose of locks is to eliminate the slope.
$endgroup$
– Ray Butterworth
2 days ago




3




3




$begingroup$
This seems to be what you want : lmnoeng.com/Channels/trapezoid.php
$endgroup$
– Ville Niemi
yesterday




$begingroup$
This seems to be what you want : lmnoeng.com/Channels/trapezoid.php
$endgroup$
– Ville Niemi
yesterday




24




24




$begingroup$
The problem is never how hard it is to pull barges upstream, the problem is always how to keep the canal filled with water. If the canal has any amount of appreciable slope water will flow downhill. Where does the water come from?
$endgroup$
– AlexP
yesterday






$begingroup$
The problem is never how hard it is to pull barges upstream, the problem is always how to keep the canal filled with water. If the canal has any amount of appreciable slope water will flow downhill. Where does the water come from?
$endgroup$
– AlexP
yesterday












6 Answers
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A canal with a gradient and a flow is a river. And navigatable rivers are pretty much flat. Taking a nearby river (the Medway) and measuring the change in height from the coast to the point at which it becomes essentially unnavigatable gives an average gradient of 0.0003 or about 30cm per kilometer. Wider rivers have lower gradients. The Mississippi has a gradient of about 1cm per km, yet still flows pretty quickly



If you have a flowing canal, you need a constant source of water. This is why canals use locks. Don't design canals as rivers, unless you already have a river to redirect through it.






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  • 4




    $begingroup$
    And here I was going to suggest canals filled with high-viscosity fluid, thus greatly diminishing the flow rate. Just coat your barges with some magic fluid-phobic material so there's no friction resistance.
    $endgroup$
    – Carl Witthoft
    yesterday






  • 46




    $begingroup$
    @CarlWitthoft Traditionally one uses the highly viscous fluid called asphalt for this, I'm just not sure if wheels count as magic friction reducing material...
    $endgroup$
    – mlk
    yesterday






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    If you have two bodies of water at different heights, then the higher one will supply the water.
    $endgroup$
    – Acccumulation
    yesterday






  • 1




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    Having a flowing canal isn't a goal, it's an unfortunate consequence of having to move between two bodies of water at different heights.
    $endgroup$
    – Brilliand
    yesterday






  • 2




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    @Acccumulation And what happens when that body of water is empty?
    $endgroup$
    – immibis
    yesterday



















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The Suez Canal is an artificial waterway of about 190 km in length running across the Isthmus of Suez in northeastern Egypt which connects the Mediterranean Seas with the Gulf of Suez, an arm of the Red Sea. It has no locks, because the Mediterranean Sea and the Gulf of Suez have roughly the same water level and is thus the world's longest canal without locks. (Source)



Karakum Canal without locks in Russia is the longest canal in the world with a total length of 1400 kilometer. It was built in 1954 and completed in 1967 having a length of 840 kilometers and further extended in 1970 and 80s up to Caspian Sea coast making its total length of 1400 kilometers. (Source)




To answer your question, 0°.



The differences in "sea level altitude" between the sources and destinations of these bodies varies naturally according to the tide, but the canals are dug such that those variations are accommodated within the canal — which can only be done when the source and destination altitudes are fundamentally equal.



There is obviously some small amount of ascent/descent or the canals/rivers used for cargo transport wouldn't have a current. But that ascent/descent need not (and almost always is not) a condition of the path being traveled by the cargo ships. For example, the Mississippi has nearly all of its descent in its northern most reaches. By the time you get to the majority of shipping in the southern U.S., it's basically flat. The current is caused by water pressure from the north.






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  • 4




    $begingroup$
    I don't think the OP is asking about sea canals; more the medieval style "river canals". They definitely have different water levels across the length of the canal, though obviously, they also used a lot of locks. 2° is the kind of grade that already gives trouble to rail traffic, I'd expect a navigable river/canal system would be substantially below 1°, especially without powered boats. Many navigable rivers have gradients in tens of centimeters per kilometer. And of course, even if a gradient is technically possible, at some point land traffic is going to be more economical anyway.
    $endgroup$
    – Luaan
    yesterday






  • 4




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    @jwenting uh, yeah you could. Literally all rivers have that. And what are canals if not redirected rivers or lakes?
    $endgroup$
    – Hobbamok
    yesterday






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    @Hobbamok you could not, unless you want to drain one end of the canal into the other. A river has something where the water originates, or it'd run dry. Canals with a grade would drain whatever is at their high point into whatever is at their low point. Which can drain entire lakes.
    $endgroup$
    – jwenting
    yesterday






  • 5




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    1 degree is a 1:60 gradient, or 16m per km - that's around 100 times steeper than most navigable rivers.
    $endgroup$
    – Robin Bennett
    yesterday






  • 4




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    "The current is caused by water pressure from the north." [citation needed] This isn't a pipeline.
    $endgroup$
    – Yakk
    yesterday





















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The gradient should be 0, UNLESS the high end of the canal has a flow rate high enough to compensate for the amount of water being drained from it by the canal into the low end.



Which for any decent sized canal would be a lot indeed and probably make the upstream end of the canal hazardous for shipping because of the rapids.



This is simple physics. Water (as any liquid really) want to establish equilibrium, meaning the surface wants to be flat and level. Thus it flows from high to low until equilibrium is established, both vessels having the same water level.



The only way to thus have a canal with one end higher than the other without an artificial barrier (a lock) in it is to ensure that the high end gains water as fast as the canal can drain it.



In theory of course you could calculate the exact drainage and pump water out of the low end at that rate, back into the high end. But locks would be much easier, cheaper, and more reliable.






share|improve this answer









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  • $begingroup$
    * where "flat" and "level" are non-technical terms referring to the imperceptible curve that water follows to maintain an equal gravitational potential...
    $endgroup$
    – JCRM
    yesterday










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    You don't need a pump, if natural processes are filling it up. And even if there's a net flow, it can still take years to level off, if the flow is small enough and the volume is large enough.
    $endgroup$
    – Acccumulation
    yesterday






  • 2




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    @Acccumulation A canal dependent civilisation, requires functional canals. Investing in a Canal that would suffer at the hands of intermittent weather, or potentially would ruin the already established network of canals is a bad investment. It would be like investing in a rail line which would work fine for the next 10 years except for droughts, and will prevent any trains on linked rails from running after that. Requiring either a massive refurbishment program or new technology to fix.
    $endgroup$
    – Kain0_0
    21 hours ago










  • $begingroup$
    @Kain0_0 I'm taking the the desire for flow to be motivated by out-of-universe plot reasons, and not an in-universe desire of the characters. And according to this article, it would take the Amazon six years to empty a body of water the size of the Mediterranean Sea. So if you had a canal with a flow one hundredth of the Amazon, it would take six hundred years. And with rain, it wouldn't suffer at the hand of intermittent weather, since it would take six hundred years of drought to empty it.
    $endgroup$
    – Acccumulation
    12 hours ago



















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Your only limiter is how much your beasts of burden can drag up river. This is less dependent on slope than it is on the speed of flow and shape of the hull. Personally I'd favour double hulled boats if your channel is wide enough, they cut through water pretty well while giving you width for cargo space. Whereas a similar single hull would probably need to be a long thin boat in a heavy current.






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$endgroup$









  • 1




    $begingroup$
    So, the more hydrodynamic the boat hull is, the easier it is to be pulled through the water. That sort of makes sense.
    $endgroup$
    – GiruŠatuku
    yesterday






  • 4




    $begingroup$
    The limiter is that the water will flow out of your canal at the bottom end leaving it empty of water, unless it is refilled at the top, in which case it is a river.
    $endgroup$
    – rghome
    yesterday






  • 3




    $begingroup$
    If you're talking about a catamaran, they're generally referred to as twin-hulled. "Double hull" generally refers to a hull inside a hull.
    $endgroup$
    – Acccumulation
    yesterday






  • 2




    $begingroup$
    @Acccumulation maybe where you come from, over here no, and I'm Polynesian, we invented these vessels over 2000 years ago.
    $endgroup$
    – Kilisi
    23 hours ago










  • $begingroup$
    @Kilisi "Hull" is not a Polynesian term. While "double hull" can refer to catamarans, "twin-hulled" is significantly less ambiguous.
    $endgroup$
    – Acccumulation
    12 hours ago



















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I wonder if Tesla valve-shaped channel would work for you. It can make flow 10-100 times slower than unimpeded one, so I guess in theory 1/10 gradient would become possible. But it works best with pulsed flow and when covered so I am not sure if it would work in this case.






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    0












    $begingroup$

    If your canal empties into the Bay of Fundy, you've got fifty feet of vertical displacement to work with, thanks to the tides.



    You can achieve whatever angle you might fancy by varying the length of your canal.






    share|improve this answer









    $endgroup$














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      6 Answers
      6






      active

      oldest

      votes








      6 Answers
      6






      active

      oldest

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      active

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      active

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      53












      $begingroup$

      A canal with a gradient and a flow is a river. And navigatable rivers are pretty much flat. Taking a nearby river (the Medway) and measuring the change in height from the coast to the point at which it becomes essentially unnavigatable gives an average gradient of 0.0003 or about 30cm per kilometer. Wider rivers have lower gradients. The Mississippi has a gradient of about 1cm per km, yet still flows pretty quickly



      If you have a flowing canal, you need a constant source of water. This is why canals use locks. Don't design canals as rivers, unless you already have a river to redirect through it.






      share|improve this answer









      $endgroup$









      • 4




        $begingroup$
        And here I was going to suggest canals filled with high-viscosity fluid, thus greatly diminishing the flow rate. Just coat your barges with some magic fluid-phobic material so there's no friction resistance.
        $endgroup$
        – Carl Witthoft
        yesterday






      • 46




        $begingroup$
        @CarlWitthoft Traditionally one uses the highly viscous fluid called asphalt for this, I'm just not sure if wheels count as magic friction reducing material...
        $endgroup$
        – mlk
        yesterday






      • 1




        $begingroup$
        If you have two bodies of water at different heights, then the higher one will supply the water.
        $endgroup$
        – Acccumulation
        yesterday






      • 1




        $begingroup$
        Having a flowing canal isn't a goal, it's an unfortunate consequence of having to move between two bodies of water at different heights.
        $endgroup$
        – Brilliand
        yesterday






      • 2




        $begingroup$
        @Acccumulation And what happens when that body of water is empty?
        $endgroup$
        – immibis
        yesterday
















      53












      $begingroup$

      A canal with a gradient and a flow is a river. And navigatable rivers are pretty much flat. Taking a nearby river (the Medway) and measuring the change in height from the coast to the point at which it becomes essentially unnavigatable gives an average gradient of 0.0003 or about 30cm per kilometer. Wider rivers have lower gradients. The Mississippi has a gradient of about 1cm per km, yet still flows pretty quickly



      If you have a flowing canal, you need a constant source of water. This is why canals use locks. Don't design canals as rivers, unless you already have a river to redirect through it.






      share|improve this answer









      $endgroup$









      • 4




        $begingroup$
        And here I was going to suggest canals filled with high-viscosity fluid, thus greatly diminishing the flow rate. Just coat your barges with some magic fluid-phobic material so there's no friction resistance.
        $endgroup$
        – Carl Witthoft
        yesterday






      • 46




        $begingroup$
        @CarlWitthoft Traditionally one uses the highly viscous fluid called asphalt for this, I'm just not sure if wheels count as magic friction reducing material...
        $endgroup$
        – mlk
        yesterday






      • 1




        $begingroup$
        If you have two bodies of water at different heights, then the higher one will supply the water.
        $endgroup$
        – Acccumulation
        yesterday






      • 1




        $begingroup$
        Having a flowing canal isn't a goal, it's an unfortunate consequence of having to move between two bodies of water at different heights.
        $endgroup$
        – Brilliand
        yesterday






      • 2




        $begingroup$
        @Acccumulation And what happens when that body of water is empty?
        $endgroup$
        – immibis
        yesterday














      53












      53








      53





      $begingroup$

      A canal with a gradient and a flow is a river. And navigatable rivers are pretty much flat. Taking a nearby river (the Medway) and measuring the change in height from the coast to the point at which it becomes essentially unnavigatable gives an average gradient of 0.0003 or about 30cm per kilometer. Wider rivers have lower gradients. The Mississippi has a gradient of about 1cm per km, yet still flows pretty quickly



      If you have a flowing canal, you need a constant source of water. This is why canals use locks. Don't design canals as rivers, unless you already have a river to redirect through it.






      share|improve this answer









      $endgroup$



      A canal with a gradient and a flow is a river. And navigatable rivers are pretty much flat. Taking a nearby river (the Medway) and measuring the change in height from the coast to the point at which it becomes essentially unnavigatable gives an average gradient of 0.0003 or about 30cm per kilometer. Wider rivers have lower gradients. The Mississippi has a gradient of about 1cm per km, yet still flows pretty quickly



      If you have a flowing canal, you need a constant source of water. This is why canals use locks. Don't design canals as rivers, unless you already have a river to redirect through it.







      share|improve this answer












      share|improve this answer



      share|improve this answer










      answered yesterday









      James KJames K

      9,1022044




      9,1022044








      • 4




        $begingroup$
        And here I was going to suggest canals filled with high-viscosity fluid, thus greatly diminishing the flow rate. Just coat your barges with some magic fluid-phobic material so there's no friction resistance.
        $endgroup$
        – Carl Witthoft
        yesterday






      • 46




        $begingroup$
        @CarlWitthoft Traditionally one uses the highly viscous fluid called asphalt for this, I'm just not sure if wheels count as magic friction reducing material...
        $endgroup$
        – mlk
        yesterday






      • 1




        $begingroup$
        If you have two bodies of water at different heights, then the higher one will supply the water.
        $endgroup$
        – Acccumulation
        yesterday






      • 1




        $begingroup$
        Having a flowing canal isn't a goal, it's an unfortunate consequence of having to move between two bodies of water at different heights.
        $endgroup$
        – Brilliand
        yesterday






      • 2




        $begingroup$
        @Acccumulation And what happens when that body of water is empty?
        $endgroup$
        – immibis
        yesterday














      • 4




        $begingroup$
        And here I was going to suggest canals filled with high-viscosity fluid, thus greatly diminishing the flow rate. Just coat your barges with some magic fluid-phobic material so there's no friction resistance.
        $endgroup$
        – Carl Witthoft
        yesterday






      • 46




        $begingroup$
        @CarlWitthoft Traditionally one uses the highly viscous fluid called asphalt for this, I'm just not sure if wheels count as magic friction reducing material...
        $endgroup$
        – mlk
        yesterday






      • 1




        $begingroup$
        If you have two bodies of water at different heights, then the higher one will supply the water.
        $endgroup$
        – Acccumulation
        yesterday






      • 1




        $begingroup$
        Having a flowing canal isn't a goal, it's an unfortunate consequence of having to move between two bodies of water at different heights.
        $endgroup$
        – Brilliand
        yesterday






      • 2




        $begingroup$
        @Acccumulation And what happens when that body of water is empty?
        $endgroup$
        – immibis
        yesterday








      4




      4




      $begingroup$
      And here I was going to suggest canals filled with high-viscosity fluid, thus greatly diminishing the flow rate. Just coat your barges with some magic fluid-phobic material so there's no friction resistance.
      $endgroup$
      – Carl Witthoft
      yesterday




      $begingroup$
      And here I was going to suggest canals filled with high-viscosity fluid, thus greatly diminishing the flow rate. Just coat your barges with some magic fluid-phobic material so there's no friction resistance.
      $endgroup$
      – Carl Witthoft
      yesterday




      46




      46




      $begingroup$
      @CarlWitthoft Traditionally one uses the highly viscous fluid called asphalt for this, I'm just not sure if wheels count as magic friction reducing material...
      $endgroup$
      – mlk
      yesterday




      $begingroup$
      @CarlWitthoft Traditionally one uses the highly viscous fluid called asphalt for this, I'm just not sure if wheels count as magic friction reducing material...
      $endgroup$
      – mlk
      yesterday




      1




      1




      $begingroup$
      If you have two bodies of water at different heights, then the higher one will supply the water.
      $endgroup$
      – Acccumulation
      yesterday




      $begingroup$
      If you have two bodies of water at different heights, then the higher one will supply the water.
      $endgroup$
      – Acccumulation
      yesterday




      1




      1




      $begingroup$
      Having a flowing canal isn't a goal, it's an unfortunate consequence of having to move between two bodies of water at different heights.
      $endgroup$
      – Brilliand
      yesterday




      $begingroup$
      Having a flowing canal isn't a goal, it's an unfortunate consequence of having to move between two bodies of water at different heights.
      $endgroup$
      – Brilliand
      yesterday




      2




      2




      $begingroup$
      @Acccumulation And what happens when that body of water is empty?
      $endgroup$
      – immibis
      yesterday




      $begingroup$
      @Acccumulation And what happens when that body of water is empty?
      $endgroup$
      – immibis
      yesterday











      13












      $begingroup$


      The Suez Canal is an artificial waterway of about 190 km in length running across the Isthmus of Suez in northeastern Egypt which connects the Mediterranean Seas with the Gulf of Suez, an arm of the Red Sea. It has no locks, because the Mediterranean Sea and the Gulf of Suez have roughly the same water level and is thus the world's longest canal without locks. (Source)



      Karakum Canal without locks in Russia is the longest canal in the world with a total length of 1400 kilometer. It was built in 1954 and completed in 1967 having a length of 840 kilometers and further extended in 1970 and 80s up to Caspian Sea coast making its total length of 1400 kilometers. (Source)




      To answer your question, 0°.



      The differences in "sea level altitude" between the sources and destinations of these bodies varies naturally according to the tide, but the canals are dug such that those variations are accommodated within the canal — which can only be done when the source and destination altitudes are fundamentally equal.



      There is obviously some small amount of ascent/descent or the canals/rivers used for cargo transport wouldn't have a current. But that ascent/descent need not (and almost always is not) a condition of the path being traveled by the cargo ships. For example, the Mississippi has nearly all of its descent in its northern most reaches. By the time you get to the majority of shipping in the southern U.S., it's basically flat. The current is caused by water pressure from the north.






      share|improve this answer











      $endgroup$









      • 4




        $begingroup$
        I don't think the OP is asking about sea canals; more the medieval style "river canals". They definitely have different water levels across the length of the canal, though obviously, they also used a lot of locks. 2° is the kind of grade that already gives trouble to rail traffic, I'd expect a navigable river/canal system would be substantially below 1°, especially without powered boats. Many navigable rivers have gradients in tens of centimeters per kilometer. And of course, even if a gradient is technically possible, at some point land traffic is going to be more economical anyway.
        $endgroup$
        – Luaan
        yesterday






      • 4




        $begingroup$
        @jwenting uh, yeah you could. Literally all rivers have that. And what are canals if not redirected rivers or lakes?
        $endgroup$
        – Hobbamok
        yesterday






      • 3




        $begingroup$
        @Hobbamok you could not, unless you want to drain one end of the canal into the other. A river has something where the water originates, or it'd run dry. Canals with a grade would drain whatever is at their high point into whatever is at their low point. Which can drain entire lakes.
        $endgroup$
        – jwenting
        yesterday






      • 5




        $begingroup$
        1 degree is a 1:60 gradient, or 16m per km - that's around 100 times steeper than most navigable rivers.
        $endgroup$
        – Robin Bennett
        yesterday






      • 4




        $begingroup$
        "The current is caused by water pressure from the north." [citation needed] This isn't a pipeline.
        $endgroup$
        – Yakk
        yesterday


















      13












      $begingroup$


      The Suez Canal is an artificial waterway of about 190 km in length running across the Isthmus of Suez in northeastern Egypt which connects the Mediterranean Seas with the Gulf of Suez, an arm of the Red Sea. It has no locks, because the Mediterranean Sea and the Gulf of Suez have roughly the same water level and is thus the world's longest canal without locks. (Source)



      Karakum Canal without locks in Russia is the longest canal in the world with a total length of 1400 kilometer. It was built in 1954 and completed in 1967 having a length of 840 kilometers and further extended in 1970 and 80s up to Caspian Sea coast making its total length of 1400 kilometers. (Source)




      To answer your question, 0°.



      The differences in "sea level altitude" between the sources and destinations of these bodies varies naturally according to the tide, but the canals are dug such that those variations are accommodated within the canal — which can only be done when the source and destination altitudes are fundamentally equal.



      There is obviously some small amount of ascent/descent or the canals/rivers used for cargo transport wouldn't have a current. But that ascent/descent need not (and almost always is not) a condition of the path being traveled by the cargo ships. For example, the Mississippi has nearly all of its descent in its northern most reaches. By the time you get to the majority of shipping in the southern U.S., it's basically flat. The current is caused by water pressure from the north.






      share|improve this answer











      $endgroup$









      • 4




        $begingroup$
        I don't think the OP is asking about sea canals; more the medieval style "river canals". They definitely have different water levels across the length of the canal, though obviously, they also used a lot of locks. 2° is the kind of grade that already gives trouble to rail traffic, I'd expect a navigable river/canal system would be substantially below 1°, especially without powered boats. Many navigable rivers have gradients in tens of centimeters per kilometer. And of course, even if a gradient is technically possible, at some point land traffic is going to be more economical anyway.
        $endgroup$
        – Luaan
        yesterday






      • 4




        $begingroup$
        @jwenting uh, yeah you could. Literally all rivers have that. And what are canals if not redirected rivers or lakes?
        $endgroup$
        – Hobbamok
        yesterday






      • 3




        $begingroup$
        @Hobbamok you could not, unless you want to drain one end of the canal into the other. A river has something where the water originates, or it'd run dry. Canals with a grade would drain whatever is at their high point into whatever is at their low point. Which can drain entire lakes.
        $endgroup$
        – jwenting
        yesterday






      • 5




        $begingroup$
        1 degree is a 1:60 gradient, or 16m per km - that's around 100 times steeper than most navigable rivers.
        $endgroup$
        – Robin Bennett
        yesterday






      • 4




        $begingroup$
        "The current is caused by water pressure from the north." [citation needed] This isn't a pipeline.
        $endgroup$
        – Yakk
        yesterday
















      13












      13








      13





      $begingroup$


      The Suez Canal is an artificial waterway of about 190 km in length running across the Isthmus of Suez in northeastern Egypt which connects the Mediterranean Seas with the Gulf of Suez, an arm of the Red Sea. It has no locks, because the Mediterranean Sea and the Gulf of Suez have roughly the same water level and is thus the world's longest canal without locks. (Source)



      Karakum Canal without locks in Russia is the longest canal in the world with a total length of 1400 kilometer. It was built in 1954 and completed in 1967 having a length of 840 kilometers and further extended in 1970 and 80s up to Caspian Sea coast making its total length of 1400 kilometers. (Source)




      To answer your question, 0°.



      The differences in "sea level altitude" between the sources and destinations of these bodies varies naturally according to the tide, but the canals are dug such that those variations are accommodated within the canal — which can only be done when the source and destination altitudes are fundamentally equal.



      There is obviously some small amount of ascent/descent or the canals/rivers used for cargo transport wouldn't have a current. But that ascent/descent need not (and almost always is not) a condition of the path being traveled by the cargo ships. For example, the Mississippi has nearly all of its descent in its northern most reaches. By the time you get to the majority of shipping in the southern U.S., it's basically flat. The current is caused by water pressure from the north.






      share|improve this answer











      $endgroup$




      The Suez Canal is an artificial waterway of about 190 km in length running across the Isthmus of Suez in northeastern Egypt which connects the Mediterranean Seas with the Gulf of Suez, an arm of the Red Sea. It has no locks, because the Mediterranean Sea and the Gulf of Suez have roughly the same water level and is thus the world's longest canal without locks. (Source)



      Karakum Canal without locks in Russia is the longest canal in the world with a total length of 1400 kilometer. It was built in 1954 and completed in 1967 having a length of 840 kilometers and further extended in 1970 and 80s up to Caspian Sea coast making its total length of 1400 kilometers. (Source)




      To answer your question, 0°.



      The differences in "sea level altitude" between the sources and destinations of these bodies varies naturally according to the tide, but the canals are dug such that those variations are accommodated within the canal — which can only be done when the source and destination altitudes are fundamentally equal.



      There is obviously some small amount of ascent/descent or the canals/rivers used for cargo transport wouldn't have a current. But that ascent/descent need not (and almost always is not) a condition of the path being traveled by the cargo ships. For example, the Mississippi has nearly all of its descent in its northern most reaches. By the time you get to the majority of shipping in the southern U.S., it's basically flat. The current is caused by water pressure from the north.







      share|improve this answer














      share|improve this answer



      share|improve this answer








      edited yesterday

























      answered 2 days ago









      JBHJBH

      48k699227




      48k699227








      • 4




        $begingroup$
        I don't think the OP is asking about sea canals; more the medieval style "river canals". They definitely have different water levels across the length of the canal, though obviously, they also used a lot of locks. 2° is the kind of grade that already gives trouble to rail traffic, I'd expect a navigable river/canal system would be substantially below 1°, especially without powered boats. Many navigable rivers have gradients in tens of centimeters per kilometer. And of course, even if a gradient is technically possible, at some point land traffic is going to be more economical anyway.
        $endgroup$
        – Luaan
        yesterday






      • 4




        $begingroup$
        @jwenting uh, yeah you could. Literally all rivers have that. And what are canals if not redirected rivers or lakes?
        $endgroup$
        – Hobbamok
        yesterday






      • 3




        $begingroup$
        @Hobbamok you could not, unless you want to drain one end of the canal into the other. A river has something where the water originates, or it'd run dry. Canals with a grade would drain whatever is at their high point into whatever is at their low point. Which can drain entire lakes.
        $endgroup$
        – jwenting
        yesterday






      • 5




        $begingroup$
        1 degree is a 1:60 gradient, or 16m per km - that's around 100 times steeper than most navigable rivers.
        $endgroup$
        – Robin Bennett
        yesterday






      • 4




        $begingroup$
        "The current is caused by water pressure from the north." [citation needed] This isn't a pipeline.
        $endgroup$
        – Yakk
        yesterday
















      • 4




        $begingroup$
        I don't think the OP is asking about sea canals; more the medieval style "river canals". They definitely have different water levels across the length of the canal, though obviously, they also used a lot of locks. 2° is the kind of grade that already gives trouble to rail traffic, I'd expect a navigable river/canal system would be substantially below 1°, especially without powered boats. Many navigable rivers have gradients in tens of centimeters per kilometer. And of course, even if a gradient is technically possible, at some point land traffic is going to be more economical anyway.
        $endgroup$
        – Luaan
        yesterday






      • 4




        $begingroup$
        @jwenting uh, yeah you could. Literally all rivers have that. And what are canals if not redirected rivers or lakes?
        $endgroup$
        – Hobbamok
        yesterday






      • 3




        $begingroup$
        @Hobbamok you could not, unless you want to drain one end of the canal into the other. A river has something where the water originates, or it'd run dry. Canals with a grade would drain whatever is at their high point into whatever is at their low point. Which can drain entire lakes.
        $endgroup$
        – jwenting
        yesterday






      • 5




        $begingroup$
        1 degree is a 1:60 gradient, or 16m per km - that's around 100 times steeper than most navigable rivers.
        $endgroup$
        – Robin Bennett
        yesterday






      • 4




        $begingroup$
        "The current is caused by water pressure from the north." [citation needed] This isn't a pipeline.
        $endgroup$
        – Yakk
        yesterday










      4




      4




      $begingroup$
      I don't think the OP is asking about sea canals; more the medieval style "river canals". They definitely have different water levels across the length of the canal, though obviously, they also used a lot of locks. 2° is the kind of grade that already gives trouble to rail traffic, I'd expect a navigable river/canal system would be substantially below 1°, especially without powered boats. Many navigable rivers have gradients in tens of centimeters per kilometer. And of course, even if a gradient is technically possible, at some point land traffic is going to be more economical anyway.
      $endgroup$
      – Luaan
      yesterday




      $begingroup$
      I don't think the OP is asking about sea canals; more the medieval style "river canals". They definitely have different water levels across the length of the canal, though obviously, they also used a lot of locks. 2° is the kind of grade that already gives trouble to rail traffic, I'd expect a navigable river/canal system would be substantially below 1°, especially without powered boats. Many navigable rivers have gradients in tens of centimeters per kilometer. And of course, even if a gradient is technically possible, at some point land traffic is going to be more economical anyway.
      $endgroup$
      – Luaan
      yesterday




      4




      4




      $begingroup$
      @jwenting uh, yeah you could. Literally all rivers have that. And what are canals if not redirected rivers or lakes?
      $endgroup$
      – Hobbamok
      yesterday




      $begingroup$
      @jwenting uh, yeah you could. Literally all rivers have that. And what are canals if not redirected rivers or lakes?
      $endgroup$
      – Hobbamok
      yesterday




      3




      3




      $begingroup$
      @Hobbamok you could not, unless you want to drain one end of the canal into the other. A river has something where the water originates, or it'd run dry. Canals with a grade would drain whatever is at their high point into whatever is at their low point. Which can drain entire lakes.
      $endgroup$
      – jwenting
      yesterday




      $begingroup$
      @Hobbamok you could not, unless you want to drain one end of the canal into the other. A river has something where the water originates, or it'd run dry. Canals with a grade would drain whatever is at their high point into whatever is at their low point. Which can drain entire lakes.
      $endgroup$
      – jwenting
      yesterday




      5




      5




      $begingroup$
      1 degree is a 1:60 gradient, or 16m per km - that's around 100 times steeper than most navigable rivers.
      $endgroup$
      – Robin Bennett
      yesterday




      $begingroup$
      1 degree is a 1:60 gradient, or 16m per km - that's around 100 times steeper than most navigable rivers.
      $endgroup$
      – Robin Bennett
      yesterday




      4




      4




      $begingroup$
      "The current is caused by water pressure from the north." [citation needed] This isn't a pipeline.
      $endgroup$
      – Yakk
      yesterday






      $begingroup$
      "The current is caused by water pressure from the north." [citation needed] This isn't a pipeline.
      $endgroup$
      – Yakk
      yesterday













      6












      $begingroup$

      The gradient should be 0, UNLESS the high end of the canal has a flow rate high enough to compensate for the amount of water being drained from it by the canal into the low end.



      Which for any decent sized canal would be a lot indeed and probably make the upstream end of the canal hazardous for shipping because of the rapids.



      This is simple physics. Water (as any liquid really) want to establish equilibrium, meaning the surface wants to be flat and level. Thus it flows from high to low until equilibrium is established, both vessels having the same water level.



      The only way to thus have a canal with one end higher than the other without an artificial barrier (a lock) in it is to ensure that the high end gains water as fast as the canal can drain it.



      In theory of course you could calculate the exact drainage and pump water out of the low end at that rate, back into the high end. But locks would be much easier, cheaper, and more reliable.






      share|improve this answer









      $endgroup$













      • $begingroup$
        * where "flat" and "level" are non-technical terms referring to the imperceptible curve that water follows to maintain an equal gravitational potential...
        $endgroup$
        – JCRM
        yesterday










      • $begingroup$
        You don't need a pump, if natural processes are filling it up. And even if there's a net flow, it can still take years to level off, if the flow is small enough and the volume is large enough.
        $endgroup$
        – Acccumulation
        yesterday






      • 2




        $begingroup$
        @Acccumulation A canal dependent civilisation, requires functional canals. Investing in a Canal that would suffer at the hands of intermittent weather, or potentially would ruin the already established network of canals is a bad investment. It would be like investing in a rail line which would work fine for the next 10 years except for droughts, and will prevent any trains on linked rails from running after that. Requiring either a massive refurbishment program or new technology to fix.
        $endgroup$
        – Kain0_0
        21 hours ago










      • $begingroup$
        @Kain0_0 I'm taking the the desire for flow to be motivated by out-of-universe plot reasons, and not an in-universe desire of the characters. And according to this article, it would take the Amazon six years to empty a body of water the size of the Mediterranean Sea. So if you had a canal with a flow one hundredth of the Amazon, it would take six hundred years. And with rain, it wouldn't suffer at the hand of intermittent weather, since it would take six hundred years of drought to empty it.
        $endgroup$
        – Acccumulation
        12 hours ago
















      6












      $begingroup$

      The gradient should be 0, UNLESS the high end of the canal has a flow rate high enough to compensate for the amount of water being drained from it by the canal into the low end.



      Which for any decent sized canal would be a lot indeed and probably make the upstream end of the canal hazardous for shipping because of the rapids.



      This is simple physics. Water (as any liquid really) want to establish equilibrium, meaning the surface wants to be flat and level. Thus it flows from high to low until equilibrium is established, both vessels having the same water level.



      The only way to thus have a canal with one end higher than the other without an artificial barrier (a lock) in it is to ensure that the high end gains water as fast as the canal can drain it.



      In theory of course you could calculate the exact drainage and pump water out of the low end at that rate, back into the high end. But locks would be much easier, cheaper, and more reliable.






      share|improve this answer









      $endgroup$













      • $begingroup$
        * where "flat" and "level" are non-technical terms referring to the imperceptible curve that water follows to maintain an equal gravitational potential...
        $endgroup$
        – JCRM
        yesterday










      • $begingroup$
        You don't need a pump, if natural processes are filling it up. And even if there's a net flow, it can still take years to level off, if the flow is small enough and the volume is large enough.
        $endgroup$
        – Acccumulation
        yesterday






      • 2




        $begingroup$
        @Acccumulation A canal dependent civilisation, requires functional canals. Investing in a Canal that would suffer at the hands of intermittent weather, or potentially would ruin the already established network of canals is a bad investment. It would be like investing in a rail line which would work fine for the next 10 years except for droughts, and will prevent any trains on linked rails from running after that. Requiring either a massive refurbishment program or new technology to fix.
        $endgroup$
        – Kain0_0
        21 hours ago










      • $begingroup$
        @Kain0_0 I'm taking the the desire for flow to be motivated by out-of-universe plot reasons, and not an in-universe desire of the characters. And according to this article, it would take the Amazon six years to empty a body of water the size of the Mediterranean Sea. So if you had a canal with a flow one hundredth of the Amazon, it would take six hundred years. And with rain, it wouldn't suffer at the hand of intermittent weather, since it would take six hundred years of drought to empty it.
        $endgroup$
        – Acccumulation
        12 hours ago














      6












      6








      6





      $begingroup$

      The gradient should be 0, UNLESS the high end of the canal has a flow rate high enough to compensate for the amount of water being drained from it by the canal into the low end.



      Which for any decent sized canal would be a lot indeed and probably make the upstream end of the canal hazardous for shipping because of the rapids.



      This is simple physics. Water (as any liquid really) want to establish equilibrium, meaning the surface wants to be flat and level. Thus it flows from high to low until equilibrium is established, both vessels having the same water level.



      The only way to thus have a canal with one end higher than the other without an artificial barrier (a lock) in it is to ensure that the high end gains water as fast as the canal can drain it.



      In theory of course you could calculate the exact drainage and pump water out of the low end at that rate, back into the high end. But locks would be much easier, cheaper, and more reliable.






      share|improve this answer









      $endgroup$



      The gradient should be 0, UNLESS the high end of the canal has a flow rate high enough to compensate for the amount of water being drained from it by the canal into the low end.



      Which for any decent sized canal would be a lot indeed and probably make the upstream end of the canal hazardous for shipping because of the rapids.



      This is simple physics. Water (as any liquid really) want to establish equilibrium, meaning the surface wants to be flat and level. Thus it flows from high to low until equilibrium is established, both vessels having the same water level.



      The only way to thus have a canal with one end higher than the other without an artificial barrier (a lock) in it is to ensure that the high end gains water as fast as the canal can drain it.



      In theory of course you could calculate the exact drainage and pump water out of the low end at that rate, back into the high end. But locks would be much easier, cheaper, and more reliable.







      share|improve this answer












      share|improve this answer



      share|improve this answer










      answered yesterday









      jwentingjwenting

      1,91258




      1,91258












      • $begingroup$
        * where "flat" and "level" are non-technical terms referring to the imperceptible curve that water follows to maintain an equal gravitational potential...
        $endgroup$
        – JCRM
        yesterday










      • $begingroup$
        You don't need a pump, if natural processes are filling it up. And even if there's a net flow, it can still take years to level off, if the flow is small enough and the volume is large enough.
        $endgroup$
        – Acccumulation
        yesterday






      • 2




        $begingroup$
        @Acccumulation A canal dependent civilisation, requires functional canals. Investing in a Canal that would suffer at the hands of intermittent weather, or potentially would ruin the already established network of canals is a bad investment. It would be like investing in a rail line which would work fine for the next 10 years except for droughts, and will prevent any trains on linked rails from running after that. Requiring either a massive refurbishment program or new technology to fix.
        $endgroup$
        – Kain0_0
        21 hours ago










      • $begingroup$
        @Kain0_0 I'm taking the the desire for flow to be motivated by out-of-universe plot reasons, and not an in-universe desire of the characters. And according to this article, it would take the Amazon six years to empty a body of water the size of the Mediterranean Sea. So if you had a canal with a flow one hundredth of the Amazon, it would take six hundred years. And with rain, it wouldn't suffer at the hand of intermittent weather, since it would take six hundred years of drought to empty it.
        $endgroup$
        – Acccumulation
        12 hours ago


















      • $begingroup$
        * where "flat" and "level" are non-technical terms referring to the imperceptible curve that water follows to maintain an equal gravitational potential...
        $endgroup$
        – JCRM
        yesterday










      • $begingroup$
        You don't need a pump, if natural processes are filling it up. And even if there's a net flow, it can still take years to level off, if the flow is small enough and the volume is large enough.
        $endgroup$
        – Acccumulation
        yesterday






      • 2




        $begingroup$
        @Acccumulation A canal dependent civilisation, requires functional canals. Investing in a Canal that would suffer at the hands of intermittent weather, or potentially would ruin the already established network of canals is a bad investment. It would be like investing in a rail line which would work fine for the next 10 years except for droughts, and will prevent any trains on linked rails from running after that. Requiring either a massive refurbishment program or new technology to fix.
        $endgroup$
        – Kain0_0
        21 hours ago










      • $begingroup$
        @Kain0_0 I'm taking the the desire for flow to be motivated by out-of-universe plot reasons, and not an in-universe desire of the characters. And according to this article, it would take the Amazon six years to empty a body of water the size of the Mediterranean Sea. So if you had a canal with a flow one hundredth of the Amazon, it would take six hundred years. And with rain, it wouldn't suffer at the hand of intermittent weather, since it would take six hundred years of drought to empty it.
        $endgroup$
        – Acccumulation
        12 hours ago
















      $begingroup$
      * where "flat" and "level" are non-technical terms referring to the imperceptible curve that water follows to maintain an equal gravitational potential...
      $endgroup$
      – JCRM
      yesterday




      $begingroup$
      * where "flat" and "level" are non-technical terms referring to the imperceptible curve that water follows to maintain an equal gravitational potential...
      $endgroup$
      – JCRM
      yesterday












      $begingroup$
      You don't need a pump, if natural processes are filling it up. And even if there's a net flow, it can still take years to level off, if the flow is small enough and the volume is large enough.
      $endgroup$
      – Acccumulation
      yesterday




      $begingroup$
      You don't need a pump, if natural processes are filling it up. And even if there's a net flow, it can still take years to level off, if the flow is small enough and the volume is large enough.
      $endgroup$
      – Acccumulation
      yesterday




      2




      2




      $begingroup$
      @Acccumulation A canal dependent civilisation, requires functional canals. Investing in a Canal that would suffer at the hands of intermittent weather, or potentially would ruin the already established network of canals is a bad investment. It would be like investing in a rail line which would work fine for the next 10 years except for droughts, and will prevent any trains on linked rails from running after that. Requiring either a massive refurbishment program or new technology to fix.
      $endgroup$
      – Kain0_0
      21 hours ago




      $begingroup$
      @Acccumulation A canal dependent civilisation, requires functional canals. Investing in a Canal that would suffer at the hands of intermittent weather, or potentially would ruin the already established network of canals is a bad investment. It would be like investing in a rail line which would work fine for the next 10 years except for droughts, and will prevent any trains on linked rails from running after that. Requiring either a massive refurbishment program or new technology to fix.
      $endgroup$
      – Kain0_0
      21 hours ago












      $begingroup$
      @Kain0_0 I'm taking the the desire for flow to be motivated by out-of-universe plot reasons, and not an in-universe desire of the characters. And according to this article, it would take the Amazon six years to empty a body of water the size of the Mediterranean Sea. So if you had a canal with a flow one hundredth of the Amazon, it would take six hundred years. And with rain, it wouldn't suffer at the hand of intermittent weather, since it would take six hundred years of drought to empty it.
      $endgroup$
      – Acccumulation
      12 hours ago




      $begingroup$
      @Kain0_0 I'm taking the the desire for flow to be motivated by out-of-universe plot reasons, and not an in-universe desire of the characters. And according to this article, it would take the Amazon six years to empty a body of water the size of the Mediterranean Sea. So if you had a canal with a flow one hundredth of the Amazon, it would take six hundred years. And with rain, it wouldn't suffer at the hand of intermittent weather, since it would take six hundred years of drought to empty it.
      $endgroup$
      – Acccumulation
      12 hours ago











      1












      $begingroup$

      Your only limiter is how much your beasts of burden can drag up river. This is less dependent on slope than it is on the speed of flow and shape of the hull. Personally I'd favour double hulled boats if your channel is wide enough, they cut through water pretty well while giving you width for cargo space. Whereas a similar single hull would probably need to be a long thin boat in a heavy current.






      share|improve this answer









      $endgroup$









      • 1




        $begingroup$
        So, the more hydrodynamic the boat hull is, the easier it is to be pulled through the water. That sort of makes sense.
        $endgroup$
        – GiruŠatuku
        yesterday






      • 4




        $begingroup$
        The limiter is that the water will flow out of your canal at the bottom end leaving it empty of water, unless it is refilled at the top, in which case it is a river.
        $endgroup$
        – rghome
        yesterday






      • 3




        $begingroup$
        If you're talking about a catamaran, they're generally referred to as twin-hulled. "Double hull" generally refers to a hull inside a hull.
        $endgroup$
        – Acccumulation
        yesterday






      • 2




        $begingroup$
        @Acccumulation maybe where you come from, over here no, and I'm Polynesian, we invented these vessels over 2000 years ago.
        $endgroup$
        – Kilisi
        23 hours ago










      • $begingroup$
        @Kilisi "Hull" is not a Polynesian term. While "double hull" can refer to catamarans, "twin-hulled" is significantly less ambiguous.
        $endgroup$
        – Acccumulation
        12 hours ago
















      1












      $begingroup$

      Your only limiter is how much your beasts of burden can drag up river. This is less dependent on slope than it is on the speed of flow and shape of the hull. Personally I'd favour double hulled boats if your channel is wide enough, they cut through water pretty well while giving you width for cargo space. Whereas a similar single hull would probably need to be a long thin boat in a heavy current.






      share|improve this answer









      $endgroup$









      • 1




        $begingroup$
        So, the more hydrodynamic the boat hull is, the easier it is to be pulled through the water. That sort of makes sense.
        $endgroup$
        – GiruŠatuku
        yesterday






      • 4




        $begingroup$
        The limiter is that the water will flow out of your canal at the bottom end leaving it empty of water, unless it is refilled at the top, in which case it is a river.
        $endgroup$
        – rghome
        yesterday






      • 3




        $begingroup$
        If you're talking about a catamaran, they're generally referred to as twin-hulled. "Double hull" generally refers to a hull inside a hull.
        $endgroup$
        – Acccumulation
        yesterday






      • 2




        $begingroup$
        @Acccumulation maybe where you come from, over here no, and I'm Polynesian, we invented these vessels over 2000 years ago.
        $endgroup$
        – Kilisi
        23 hours ago










      • $begingroup$
        @Kilisi "Hull" is not a Polynesian term. While "double hull" can refer to catamarans, "twin-hulled" is significantly less ambiguous.
        $endgroup$
        – Acccumulation
        12 hours ago














      1












      1








      1





      $begingroup$

      Your only limiter is how much your beasts of burden can drag up river. This is less dependent on slope than it is on the speed of flow and shape of the hull. Personally I'd favour double hulled boats if your channel is wide enough, they cut through water pretty well while giving you width for cargo space. Whereas a similar single hull would probably need to be a long thin boat in a heavy current.






      share|improve this answer









      $endgroup$



      Your only limiter is how much your beasts of burden can drag up river. This is less dependent on slope than it is on the speed of flow and shape of the hull. Personally I'd favour double hulled boats if your channel is wide enough, they cut through water pretty well while giving you width for cargo space. Whereas a similar single hull would probably need to be a long thin boat in a heavy current.







      share|improve this answer












      share|improve this answer



      share|improve this answer










      answered yesterday









      KilisiKilisi

      13.8k12261




      13.8k12261








      • 1




        $begingroup$
        So, the more hydrodynamic the boat hull is, the easier it is to be pulled through the water. That sort of makes sense.
        $endgroup$
        – GiruŠatuku
        yesterday






      • 4




        $begingroup$
        The limiter is that the water will flow out of your canal at the bottom end leaving it empty of water, unless it is refilled at the top, in which case it is a river.
        $endgroup$
        – rghome
        yesterday






      • 3




        $begingroup$
        If you're talking about a catamaran, they're generally referred to as twin-hulled. "Double hull" generally refers to a hull inside a hull.
        $endgroup$
        – Acccumulation
        yesterday






      • 2




        $begingroup$
        @Acccumulation maybe where you come from, over here no, and I'm Polynesian, we invented these vessels over 2000 years ago.
        $endgroup$
        – Kilisi
        23 hours ago










      • $begingroup$
        @Kilisi "Hull" is not a Polynesian term. While "double hull" can refer to catamarans, "twin-hulled" is significantly less ambiguous.
        $endgroup$
        – Acccumulation
        12 hours ago














      • 1




        $begingroup$
        So, the more hydrodynamic the boat hull is, the easier it is to be pulled through the water. That sort of makes sense.
        $endgroup$
        – GiruŠatuku
        yesterday






      • 4




        $begingroup$
        The limiter is that the water will flow out of your canal at the bottom end leaving it empty of water, unless it is refilled at the top, in which case it is a river.
        $endgroup$
        – rghome
        yesterday






      • 3




        $begingroup$
        If you're talking about a catamaran, they're generally referred to as twin-hulled. "Double hull" generally refers to a hull inside a hull.
        $endgroup$
        – Acccumulation
        yesterday






      • 2




        $begingroup$
        @Acccumulation maybe where you come from, over here no, and I'm Polynesian, we invented these vessels over 2000 years ago.
        $endgroup$
        – Kilisi
        23 hours ago










      • $begingroup$
        @Kilisi "Hull" is not a Polynesian term. While "double hull" can refer to catamarans, "twin-hulled" is significantly less ambiguous.
        $endgroup$
        – Acccumulation
        12 hours ago








      1




      1




      $begingroup$
      So, the more hydrodynamic the boat hull is, the easier it is to be pulled through the water. That sort of makes sense.
      $endgroup$
      – GiruŠatuku
      yesterday




      $begingroup$
      So, the more hydrodynamic the boat hull is, the easier it is to be pulled through the water. That sort of makes sense.
      $endgroup$
      – GiruŠatuku
      yesterday




      4




      4




      $begingroup$
      The limiter is that the water will flow out of your canal at the bottom end leaving it empty of water, unless it is refilled at the top, in which case it is a river.
      $endgroup$
      – rghome
      yesterday




      $begingroup$
      The limiter is that the water will flow out of your canal at the bottom end leaving it empty of water, unless it is refilled at the top, in which case it is a river.
      $endgroup$
      – rghome
      yesterday




      3




      3




      $begingroup$
      If you're talking about a catamaran, they're generally referred to as twin-hulled. "Double hull" generally refers to a hull inside a hull.
      $endgroup$
      – Acccumulation
      yesterday




      $begingroup$
      If you're talking about a catamaran, they're generally referred to as twin-hulled. "Double hull" generally refers to a hull inside a hull.
      $endgroup$
      – Acccumulation
      yesterday




      2




      2




      $begingroup$
      @Acccumulation maybe where you come from, over here no, and I'm Polynesian, we invented these vessels over 2000 years ago.
      $endgroup$
      – Kilisi
      23 hours ago




      $begingroup$
      @Acccumulation maybe where you come from, over here no, and I'm Polynesian, we invented these vessels over 2000 years ago.
      $endgroup$
      – Kilisi
      23 hours ago












      $begingroup$
      @Kilisi "Hull" is not a Polynesian term. While "double hull" can refer to catamarans, "twin-hulled" is significantly less ambiguous.
      $endgroup$
      – Acccumulation
      12 hours ago




      $begingroup$
      @Kilisi "Hull" is not a Polynesian term. While "double hull" can refer to catamarans, "twin-hulled" is significantly less ambiguous.
      $endgroup$
      – Acccumulation
      12 hours ago











      1












      $begingroup$

      I wonder if Tesla valve-shaped channel would work for you. It can make flow 10-100 times slower than unimpeded one, so I guess in theory 1/10 gradient would become possible. But it works best with pulsed flow and when covered so I am not sure if it would work in this case.






      share|improve this answer











      $endgroup$


















        1












        $begingroup$

        I wonder if Tesla valve-shaped channel would work for you. It can make flow 10-100 times slower than unimpeded one, so I guess in theory 1/10 gradient would become possible. But it works best with pulsed flow and when covered so I am not sure if it would work in this case.






        share|improve this answer











        $endgroup$
















          1












          1








          1





          $begingroup$

          I wonder if Tesla valve-shaped channel would work for you. It can make flow 10-100 times slower than unimpeded one, so I guess in theory 1/10 gradient would become possible. But it works best with pulsed flow and when covered so I am not sure if it would work in this case.






          share|improve this answer











          $endgroup$



          I wonder if Tesla valve-shaped channel would work for you. It can make flow 10-100 times slower than unimpeded one, so I guess in theory 1/10 gradient would become possible. But it works best with pulsed flow and when covered so I am not sure if it would work in this case.







          share|improve this answer














          share|improve this answer



          share|improve this answer








          edited 21 hours ago

























          answered 22 hours ago









          VashuVashu

          2,668414




          2,668414























              0












              $begingroup$

              If your canal empties into the Bay of Fundy, you've got fifty feet of vertical displacement to work with, thanks to the tides.



              You can achieve whatever angle you might fancy by varying the length of your canal.






              share|improve this answer









              $endgroup$


















                0












                $begingroup$

                If your canal empties into the Bay of Fundy, you've got fifty feet of vertical displacement to work with, thanks to the tides.



                You can achieve whatever angle you might fancy by varying the length of your canal.






                share|improve this answer









                $endgroup$
















                  0












                  0








                  0





                  $begingroup$

                  If your canal empties into the Bay of Fundy, you've got fifty feet of vertical displacement to work with, thanks to the tides.



                  You can achieve whatever angle you might fancy by varying the length of your canal.






                  share|improve this answer









                  $endgroup$



                  If your canal empties into the Bay of Fundy, you've got fifty feet of vertical displacement to work with, thanks to the tides.



                  You can achieve whatever angle you might fancy by varying the length of your canal.







                  share|improve this answer












                  share|improve this answer



                  share|improve this answer










                  answered yesterday









                  RogerRoger

                  3,135420




                  3,135420






























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