pigs and water (river and swamp)? how to fence?

I want to put some pigs on a swampy/marshy area. The problem is how to fence it because the ground is so wet - some is mud, some is standing water, it's all covered with tussocky grass. I'm not sure about getting fence posts in there solidly enough for wire fencing, and with electrical I am worried about clearing an area well enough to keep it from grounding out. One side of the area is a very steep old railway embankment fenced off with a solid fence which is two strands of barbed wire. I don't know if they'd be able to get under the wire, or if they would try to climb the bank (my brother who has experience with pigs reckons probably not but isn't totally sure). The other side, if they got out of whatever fence I manage to erect, is a small river, 6-8 feet across and 2-5 feet deep. Would they swim this? How worried would I need to be about that? My plan is to get weaners and keep them in a small paddock on a raised dry area for a while until they are used to 'homebase' and a bit bigger, then give them access to the swampy area. But I am concerned about how to keep them in a contained area of the swamp. Any advice appreciated!

This may be off-topic but I read somewhere on these forums that Bill Mollison said that you can raise 40 pigs on an acre of cattail. So that might be a good option for taking advantage of the wet conditions and having excellent pig feed.

Maybe if you do willow-fencing thick enough to hold back pigs in a few years? Willow could grow in wetland and hold its place I think.

I wouldn't bet on the barbed wire keeping pigs confined. What I would probably do if it were me is keep the pigs out of that area until they are large enough to be confined to 2-3 strands of electric wire (and well trained to the electric fence). The fewer wires needed the higher off the ground they can be which makes fencing off a paddock a lot easier. If you do use electric wire make sure to keep it well away from the barbed wire so there is no chance of somebody (person or pig) getting stuck on the barbs and getting shocked repeatedly. As far as I know pigs are quite capable swimmers so I wouldn't expect the river to be much of a barrier.

On the other hand my pigs (Large blacks and now Ossabaws) have turned everywhere they go into something resembling a WWI battlefield so I am a bit jaded on "pastured pork", but every pig is different and pork is tasty so give it a shot. Let me know if I can be of further help.