I'm not sure wether this question qualifies for being of enough "academic merit" to ask for a translation, but I'll give it a try:
This small sentence occurs in this dialogue, just to give you the context in case you should be interested in it: https://www.docdroid.net/XKwQVeB/img-20170404-0003-new.pdf.html
=> ええ、道の横を川が流れているんです。 So, as I understand it, the sentence says that the river flows across the horizontal (axis?) of the street. Is that correct? I'm really confused by this way of expressing that A crosses B. Since it feels very complicated and unnatural to me, I'm afraid that I don't understand it correctly, even more so because in context of the dialogue, they don't really pick up that information further down.
This also poses a problem for me because を appears in a function I didn't really encounter so far. When used in context of directions, I found it as a marker for going along something "道を行く" or inside of something "公園を散歩する", sometimes also in the function of crossing something like 交差点を渡る。 But this feels like a mix because its like going along the horizontal of the street... Oo
It simply feels weird xD