The green grass in the swamp area was made from a product called "pot topper" that I bought in Michaels craft store. It is designed to place on top of plant pots as a decorative covering. These toppers are cheap but they have a base underneath that needs to be removed so that the "grass" will nestle down on the layout, and that base is a pain to separate from the grass part. The toppers are round and about 6" in diameter so I needed several to cover the swamp area. There are natural segments in the grass part so it looks like dirt patches among the grasses. I added a few sagebrush trees to simulate dead trees, and added a few "dead logs" among the grass. There are a number of waterfowl and other birds in the swamp area, as well as an owl, snakes, frogs, etc. The small critters area really hard to see unless you look closely.
In the photo above you can see the steam that runs though the swamp. There is a decaying narrow gauge boxcar that fell off the trestle long ago and projects up above the water. In front of the boxcar is a rowboat with a young man rowing his sweetheart along the stream. The stream comes into the swamp area from beyond the stone pier on the left.
Above is a shot looking down at the swamp area showing the separations between the grass.
I also installed swamp sounds made by Fantasonics which I have installed on a Dream Player which is a solid state device with various options for playing sounds. Up until this sound installation I had been installing cheap CD players to play other Fantasonics sounds. In addition to the Dream Player I have a power supply designed and built by my late friend Gordon North which will support up to 5 Dream Players and, on a separate side, a supply to handle structure lighting on the layout.
Above on the right is the power supply and on the left is an amplifier for the speakers since I was using unpowered speakers. The speakers are ported out the fascia under the swamp area with one on each side of the layout corner and about 8" from the corner. That way when you stand at the corner you hear a stereo swamp sound - really neat.
The water in the stream was made with Envirotex two part epoxy resin which I prefer to the other products I have tried, including Magic Water and the Woodland Scenics product. I poured the stream several years ago and it is doing fine except I managed to mess it up a little while working on the swamp so I will be refreshing it next year.