On the Genshtab (Генштаб) Soviet military maps, I can read that this ford through the stream Вертный has a stony bottom, a depth of at most 4 dm, and a width of 29 m (under typical circumstances)¹. That is indeed fordable. It also indicates that the flow velocity is 0.6, but I can't find anywhere what unit the velocity is in. I've found an English language legend as well as a more detailed Russian language legend — screenshot below — but neither appears to describe the units. I would expect it to be km/h, but it might be m/s, which is a factor 3.6 different. What unit is it in? I'm starting to learn Russian but I don't understand enough yet to find this information.

Genshtab legend

I'm sure the quantity is speed and not total flow, because this small mountain stream (15 metre wide, 0.5 metre deep) has 2.5 speed units, whereas this river downstream (1310 metre wide, 10 metre deep) has 0.4 speed units.

¹These maps are awesome… where else in the world can you find such detail on topographic maps? Sorry, that's not my question here but I just wanted to say that :)

  • I read no Russian but a further possibility is the volume flow in cubic metres per second - this is how river flows are often measured elsewhere – Chris H Jan 19 at 20:04
  • @ChrisH No, it must be speed: this small stream in the mountains has 2.5, whereas far downstream near the mouth of the main river the value is 0.4. – gerrit Jan 19 at 21:25
  • good, that helps. Your example in the question just happened to be plausible in those units. Of course depth and speed matter directly for fording, in a way that total flow doesn't - but total flow matters for other things. – Chris H Jan 19 at 21:45
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    @ChrisH I've edited the information into the question. – gerrit Jan 19 at 21:55
  • @gerrit I don't see any fords on the map link you've provided - 29/0.4K does describe the river, but it doesn't mean there's any ford. Fords it's a "бр." supplied with details. – Usurer Jan 20 at 9:52

It's meter per second. See the more detailed legend explanation at this huge pdf

The text means "Arrows that show rivers' flow direction (0.2 is a speed of the flow in m/s)"

enter image description here

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    Good ifnd! Only now I realised that a later legend item in the more succinct legend that I found does indicate that flow speed is in m/s, so I could have guessed that the earlier legend item does, too. – gerrit Jan 20 at 10:44

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