Thread: need help from the river police

No, not geologically possible. Crossroads are roads, not rivers. Rivers do not make cross roads. Two rivers can merge together from two different sources, but they can not split apart and go to the sea in two different directions. Rivers can't do that.

GP

I'm not on the River Police, but ...

It'd be possible across one particular geological era if you were to get your bedrock elevations right. It's all just a matter of gravity. Rivers flow downhill. Just make sure the elevation of the terrain runs from high to low along the length of each river, and make sure the elevations are equal where the city is. Simple!

Eventually, erosion would alter the system, given enough time and lack of interference by terrain engineers.

Eeep, the River Police say no. I won't argue. I'm scared of incarceration.

I think what he means is that the city is considered a crossroads for trade. the picture shows the river bends coming close to each other but not touching.

It looks like the question is more along the lines of wether it's possible for two separate rivers to come close enough without merging that a city could be built so it touched the banks of each one.

Sounds geologically unlikely, but I've seen some pretty strange things on google earth

Is it possible if the rivers do not touch, as Coyotemax suggests its possible, but as Toff suggests, unless you constantly engineer otherwise, that geologic situation is temporary at best. A crossroads location wouldn't last more than a century.

Interesting idea, perhaps you could have the rivers further apart and nearly connected via a canal, but naturally rivers could not do this for very long.

GP

It's possible, just not likely or stable in geological terms. Here in the USA there are two rivers that touch and then diverge (the Mississippi and Atchafalaya). However, the junction isn't stable and requires lots of human intervention to keep them apart. This might be the case in your map. Or the distance between the rivers might be a couple of miles (still not stable geologically) and the river controls the ridge between them.

The attached images show one possible landscape configuration. It would have required two intersecting faults, one down each of the major river segments. A major earthquake would force up that final ridge that forces the rivers down each side. Note that the larger the map, the easier it is to justify the river configuration (that is, 100 feet between the rivers is highly unlikely, while 10 miles is no problem at all).

10 miles between banks isn't too bad, if there was a landing point at the bend of each, it's not so far from the city that it coulnd't be used as a central location for goods beng shipped overland at that point between the two rivers. (ok, i know there are grammar problems with that sentence, heh)

Depending on how active either of the faults are, that could add some interesting challenges to the region too

Thanks for all the quick responses guys, all comments have been helpful

Originally Posted by Coyotemax

10 miles between banks isn't too bad, if there was a landing point at the bend of each, it's not so far from the city that it coulnd't be used as a central location for goods beng shipped overland at that point between the two rivers. (ok, i know there are grammar problems with that sentence, heh)

Depending on how active either of the faults are, that could add some interesting challenges to the region too

This is pretty much what I was thinking. The city is meant to be a parallel to the city of Rome, and is the centre of a similar empire. A distance of say 10 miles between rivers makes it reasonable that settlements would form to take advantage of the proximity between the rivers, and could form a city important enough to form the keystone for a continent-spanning empire.

I also figured that any such formation would be unstable, and as such would require constant human intervention (which would be an understandable endeavor to protect such an important feature).

What sort of landscape would be most reasonable in this situation though? I was thinking a hilly landscape, with the city built on a series of hills that hold the two rivers apart. The city would have initially been two cities, one built on the bank of each river and connected by roads, that have since grown together and become a single entity.

If there was some very strong rock, this situation could last a while though? I am thinking thousands of years. Maybe more. It takes a long time for a river to wear down stone and carve a path through it I think.
So throw some strong rock into the hills and you are golden