I'm currently trying out some house rules for rivers in Hordes and Heroes and thought would share the ideas.
I've tried the rules for rivers as set out in the book, but have found they have a heavy impact on game flow when wanting to use longer stretches of river. The main reason for this is the impact they have on movement- having to stop before entry, then stopping again on entry, before being able to then move off. I had already scrapped the rule of stopping in an adjacent hex to the river before being able to enter on the next round- instead just using the same rule for woods, etc of just stopping when entering.
I have now trialled rules for shallow sections of river- these allow for any unit to cross at these points- but the unit must still stop on entry. Units fight as normal although units fighting from the bank against a unit in the shallow section of river has a +1 combat bonus. This has worked well in recent games. I've included some photos of the latest game table. The shallow river is marked with brown scatter. You can see that not all of the river is shallow, and there are also still bridges which allow for a speedy crossing.