mainly because most Dark Age battles feature rivers in some way shape or form. Probably because water features provided naturally boundaries between territories so were inevitably the place where armies clashed as expansionist Warlords came into conflict.
Anyway, a rummage round in the loft unearthed a resin river set I have a dim recollection of buying many moons ago for games of Warmaster.
these bits are actually the narrower pieces from the set, and may originally have been intended as a stream fro 28mm games.
Some rough drybrushing and the liberal application of flock and shiny gloss varnish and I have something for my Dux Bellorum forces to paddle across.