River width (Tiryiki and Shoshenstar)

[Segev]

It occurs to me that I may have been running the width of these rivers wrong. I’ve been treating it as something that you can reach either shore of in a few rounds, but these are major rivers, sluggish and wide enough to show up on a map where hexes are small on paper but represent ten miles.

How wide is a reasonable median or mode width? Should being caught in a water encounter mean you’re either stuck in the boats or definitively very close to one particular shore?

On the other hand, should it be less than a hundred feet wide so that “getting lost on an offshoot” makes more sense?

[Aett_Thorn]

Well, like most rivers, they’re probably of varying width, with some wide, flat areas, and some narrow but deep channels. But just because it is a major river doesn’t mean that it needs to be like the Mississippi. I would think that these rivers would be more like the Merrimack in NH and Mass, which powered the beginning of the Industrial Revolution. Maybe a few hundred feet wide at max, but most of it is less than 100 feet wide. Towards the start of it, there are places you can walk across, and others that are only about 50 feet wide but very deep.

[bid]

Remember that rivers become "infinitely wide" when you beach on a sandbar.:smallbiggrin:

If there are rapids upstream, silt will accumulate and form islands and channels where the flow becomes sluggish.

But yeah, the main channel might skirt an island or you may take a side channel that has a faster flow until you pick the wrong side of an island.

Also, look at https://en.wikipedia.org/wiki/Thousand_Islands for example.

[Segev]

Alright; that actually sounds like I'm not too far off on how I've been treating it. Thanks!

[Bigmouth]

The Amazon during the raining season is 26 miles across at its widest. Wow. 6.8 miles in dry season
The widest spot in the Mississippi is 2 miles across. (not counting the lakes it forms in Minnesota) This is of course a modern number with the great river completely tied up in levees and other flood control. I haven't found out how big it used to get. Still looking.
Nile: 7.5 km.
Danube: 5.5 km.
Potomac 11 miles
Delaware 300 YDs where Washington crossed.

Most modern rivers are highly controlled, but before that they would fluctuate a lot given how wet the weather was. The little creek I grew up on would routinely go from 20 feet across to a well over 100 yards across when there were heavy rains. Your river widths would depend on a lot of things, but personally big rivers are going to be several hundred yards across at a minimum. I usually go bigger of course, because everything is bigger in fantasy settings as a general rule.

[Laserlight]

Most major rovers aren't all that wide. The Seine is a couple hundred meters, the middle Rhine is a bit more, the Mississippi at Vicksburg is a bit over 1km. I mean, if you're swimming, that's a long way, but it's not "can't see the other side".

The St Lawrence is about 30 miles wide at Matane and gets wider from there, but that's unusual.

[Tiadoppler]

Keep in mind: crossing a river can be really miserable and dangerous. You're slow, wet, covered in mud, slipping on rocks you can't see, fighting against the current.


Shallow water (6 inches to 1 foot) is difficult terrain (costs 2 feet of movement to move 1 foot).

Fast shallow water (6 inches to 1 foot) is difficult terrain and requires Strength saving throws (DC 10) each turn to stay upright, if you move on that turn.

Medium water (1-3 feet) requires 2 extra feet of movement (costs 3 feet of movement to move 1 foot).

Fast medium water (1-3 feet) requires 2 extra feet of movement and requires Strength saving throws (DC 15) each turn to stay upright. If you fall prone in fast medium water, you are carried 10 feet downstream. If you hit a rock or other obstruction during this movement, you take 1d6 bludgeoning damage.

High water (3-5 feet) requires 3 extra feet of movement (costs 4 feet of movement to move 1 foot).

Fast high water (3-5 feet) requires 3 extra feet of movement and requires Strength saving throws (DC 20) each turn to stay upright. If you fall prone in fast high water, you are carried 30 feet downstream. If you hit a rock or other obstruction during this movement, you take 3d6 bludgeoning damage.

5+ feet of water requires swimming checks as usual. If you are swimming in a current, you are not connected to the ground and are carried by the current automatically. Each round that you swim in fast moving water, you are carried 40 feet downstream. If you hit a rock or other obstruction during this movement, you take 4d6 bludgeoning damage.


Note: when you're in high water, you can choose to swim (and be at the mercy of the current), or wade (which is slower). If you're wading, you can keep some of your gear dry by holding it out of the water.




The gist of it is:
Crossing fast moving rivers is frigging dangerous. Swimming into rocky rapids is absurdly dangerous. I live near a famous and beautiful river, and every couple weeks someone gets caught in the rapids and is trapped, injured or killed. Crossing rivers isn't quick or easy, and even crossing a minor stream can be challenging.

Safe fords and bridges are strategically important for a reason.



If you want an amusing video of someone wading across a large river, here you go.
Man crossing river races against a car (Top Gear). (https://youtu.be/nkL3l4bT5OU?t=260)

[Lunali]

Looking at those specific rivers on the map, I'd say at their narrowest they're probably 30-50 feet across, at their widest, miles. For most of the trip, I'd treat them as a couple hundred feet across.