I'm a no traps man, myself, so I suppose I'll have to just watch my imports and attract some migrants instead. Well, I'm not completely no traps, but I prefer the man made stuff, like channel flooding. *thinks* I could probably knock up a quick and dirty channel retractable bridge, with a ramp up.
Leave the channel empty till the Orcs come then flood it and extend the bridge, covering both exit ramps from the channel...
It'd require timing, but it should work, right?
I thought about making some Orc graphics but I haven't looked into the graphic tilesets yet. Plus I've been a bit busy which has cut into my DF time. But if nobody beats me to it I'll get around to it soon.