I came across this video, by an American. He's quite unique for a yank - saw instead of axe, wool blanket, something like hoochy cord instead of paracord, basic usable knives, everyday clothing etc. He makes a shelter and a pretty good one using strong large plastic bags, and a small tarp the size of a hoochy. He makes the bed off the ground in case of a downpour. I would have gone much simpler (and quicker), like the Australian army hoochy setup. There were a ton of dead leaves where he was. I would have set up the hoochy between two trees, quick and easy and low, like the army. Maybe one or two inches higher than normal off the ground (the low sides of the hoochy). I would have made a bed of leaves in the hoochy, like 4" or 6" high - it would probably compress down to 2". Then lay the plastic bags on top of the leaf bed. The idea is, even if it runs, and water runs under the hoochy, you're still above it on the bed of leaves, the water runs under the leaves. Ideally though you'd set up on a bit of a mound if you could. The sides of the hoochy need to be the right height - too high off the ground and water running off the hoochy sides can splash up, or even get blown in if it's windy. I've set up my tent on a swamp once - it was a swampy plain with lots of high grasses, but rock only a couple of inches under the soil - hence no where for the water to go. I just picked a huge tall grassy area and flattened it out a bit. Set up my tent on top of it. The floor of the tent was nearly half way up the inside of the tent, until I lay on it. I was sleeping on about 2" of water, but dry. I could hear a million mozzies tormented by my presence but unable to get in
Emergency shelter Actually, saw another video of his with a better idea than what I suggested; fill the heavy duty large plastic bags with leaves and use them for a mattress.