Have you checked whether the water is flowing over bedrock? The Catskills are all rock. I live here. The streams by me flow in a swale situation, the lowest point between two hillsides in the forest. When it spreads out into a marshy area, it's where the land gets more flattened out. If you want a stream, you might have to build one by excavating rock or building up the edges with rocks.

I've seen people build wooden bridges on trails here, that get you across the watery areas. That would be easier to build. Heavy rains can wash them out in a day, though.

Try gardening in the Catskills...haha. You need raised beds with trucked-in soil and lots of tall fencing that goes underground with quarter inch hardware wire at the bottom. But I do love it here. It is SO beautiful.