One thing that is guaranteed to alter the dynamics of a wargames battlefield is a river. Most gaming systems have some concept of dangerous terrain rivers usually fall slap bang into the middle of that particular category. In other words, if a river splits your table in half, then the game is likely to end up all being about one side crossing the river and the other attempting to repel any river crossings. There are so many ways you can build terrain around a river - is it a wooded river valley? A steep sided rocky gorge? A gentle rolling plain? Is there perhaps a hamlet there ? Whatever way you choose to set out your terrain around the river, the best kind of river to have is a sectional one. That is, the river itself is made up of a number of pieces of terrain that can fit together in different ways. I'd suggest you'd want straight pieces and gentle curves - that way you can alter the layout of the river and other terrain on your gaming table between games. Rivers always make for interesting games in my opinion - even if they are fordable, there is always the chance of losing troops and equipment in the crossing. If they can't be crossed like that, and you have a bridge - then the game will likely turn on taking that bridge or defending it at all costs.
Rivers can be made with suitably cut and painted sections of MDF or hardboard, using cut polystyrene foam, acrylic decorators filler or similar to make the banks. A coat of gloss varnish will make for a good water effect. Alternatively, you can use any of the specialist water effects that you can buy, made specifically to use in making wargames scenery. A thin layer of this looks very effective. Add some small rocks in the flow of the river and use filler to make the foam of water rushing round them - let your imagination run wild! If this all seems like too much hard work, you can buy ready made river sections that just need painting, or sometimes even ready painted too.
Whatever way you go, I'd suggest adding a river to your wargames scenery collection.
Wargames Terrain 6 28mm Blood Lava River Warhammer LOTR Kings Of War
Time Remaining: 9d 11h 41m
Buy It Now for only: $28.84
Wargame Terrain 1 Grey stone Rocky River or stream made for wargames trains++
Time Remaining: 8d 11h 59m
Buy It Now for only: $27.99